RU2465381C2 - Bicomponent fibers, textile sheets and their use - Google Patents

Abstract

FIELD: textiles, paper.

SUBSTANCE: bicomponent fibers contain aliphatic polyester or a mixture of aliphatic polyesters, which form the first component, and polyolefin or a mixture of polyolefins, which form the second component. Polyolefin contains auxiliary material improving its biodegradation. Textile sheets include these bicomponent fibers and are comparable by mechanical properties to textile sheets based on polyolefin, while they are decomposed more efficiently under the action of microorganisms than the textile sheets based on polyolefin.

EFFECT: enhanced biodegradability, to textile sheets such as nonwoven materials comprising these fibers, which can be used in personal care products.

16 cl, 3 tbl, 2 ex

Description

Field of Invention

The present invention relates to bicomponent core-clad fibers with improved microbial degradability. Textile sheets incorporating these fibers can be used in various applications, such as textile or industrial applications. Preferably, the textile sheets are obtained as non-woven materials that can be used in personal care products.

Level of invention

Biodegradable fibers and textile sheets obtained from them are known. One approach to improving biodegradation is the use of polymers, which are known to exhibit improved biodegradability compared to, for example, polyolefins. Another approach to improve the biodegradation of polymers is to add agents that improve the rate of biodegradation of the polymer when used.

Patents JP-A-2007-197857 and US 6197237 disclose spunbond comprising fibers of a mixture of a polyolefin and polylactic acid or a mixture of a polyolefin, an aliphatic polyester polymer and a coupling agent for both polymers. The polyolefin is present in the form of microphases in the polymer matrix of an aliphatic polyester.

US 2006/0159918 A1 discloses biodegradable fibers showing storage stability. These fibers stretch and / or curl and include a biodegradable polymer, such as an aliphatic polyester, such as polylactic acid, and show an initial strength of at least 1.5 g / denier, which remains virtually unchanged during storage for 120 days in environmental conditions.

JP 2006-030 905 A discloses a sound absorber which consists of a fiber structure material made of short polylactic acid fibers, which are a bicomponent fiber made of high molecular weight polylactic acid and low molecular weight polylactic acid. In addition, the short fiber of polylactic acid can be made in the form of a core-shell type with a polylactic core and an aromatic polyester shell.

JP 2000-054 227 A discloses a polyolefin-based conjugate fiber consisting of a first component, which is a polymer based on a polyolefin, such as polyethylene, and a second component, which is a polymer based on polylactic acid, or a mixture of selected polymers in which the second component is positioned so as to partially be visible on a portion of the fiber surface. Various configurations of bicomponent fibers are disclosed, for example, of a core-shell type having a core-polyolefin and a shell of said second component.

Improving the biodegradability of polyolefins by adding an auxiliary substance that accelerates the rate of decomposition during use is disclosed, for example, in the following documents: JP2004-182 877 A; JP 2005-255 744 A; JP 05-345 836 A; KR 1002-88 054 B; KR 10-1995-0113 175 B; KR 10-2001-0113 577 B; KR 10-2003-0071 175 B; US 3903029 A and WO 2001-39 807 A.

Excipients for improving the decomposition rate of polyolefins in use are commercially available. Examples of such substances are Envirocare (Envirocare (Ciba)), Addiflex (Addiflex (Add-X Biotech AB)) and ECM 6.0204 (ECM Biofilms).

While known products can already satisfy the requirements of biodegradation by microorganisms, these products are often not optimal in other aspects. Non-woven materials made from polylactic acid, for example, often have high shrinkage or a narrow heat-binding window. Non-woven materials made from polyolefins can avoid these shortcomings, but they are derived from oil and gas, and not from renewable primary products.

Due to the lack of fossil resources, products made from alternative plastics are becoming increasingly important now. Such alternative plastics include polymers made from renewable resources, or even polymers that are biodegradable by microorganisms or compostable. Typically, these plastics are classified as “biodegradable plastics”. Typical examples of such plastics are starch, cellulose or polylactic acid (PMA). PMK combines the benefits of renewable resources and the ability to decompose by microorganisms, offering a balanced eco-balance. Disposing of waste generated by such biodegradable plastics can be done by composting. Due to the biodegradation process, such materials will completely decompose to carbon dioxide, water and biomass. In this way, waste can be managed by composting or digging in the garbage; no heat treatment is necessary. In the melt spinning method, PMK is known as plastic with good processability. Threads with a wide fineness range can be spun. However, some weaknesses can be noted: the temperature window for the binding of PMC fibers is narrow. Thus, typically, the strength of nonwovens is lower than that known for conventional nonwovens made from polyester or polypropylene. Additionally, the high shrinkage of PMK nonwovens should be considered. The disadvantages of non-woven materials PMC can be overcome, for example, when the PMC in the fiber is coated. For example, bicomponent filaments can be made containing biodegradable plastic (such as PMC) in the core and ordinary plastic (such as polyolefin) in the shell. Such bicomponent filaments offer a wider temperature bonding window. Also, shrinkage of nonwoven materials can be successfully reduced in this way. Unfortunately, the benefits of non-woven materials made from a two-component yarn with biodegradable plastic in the core and polyolefin in the shell are combined with a loss of biodegradability or composting. The polyolefins in the shell are non-degradable plastics, protecting the biodegradable plastic in the core of the threads. Therefore, the decomposition process is slowed down, or at least hindered.

SUMMARY OF THE INVENTION

One of the objectives of the present invention is to provide fibers and textile sheets containing these fibers, which include a high proportion of renewable primary products and show the properties of, for example, a temperature binding window or shrinkage of polyolefin fibers and textile sheets made from it.

Another objective of this invention is to provide fibers and textile sheets containing these fibers that are readily biodegradable.

Another objective of this invention is to provide fibers that can be produced on conventional spinning equipment using process parameters already used in the production of polyolefin fibers.

Further objectives of this invention will become apparent from the following description.

In one embodiment, the present invention relates to bicomponent fibers comprising an aliphatic polyester or a mixture of aliphatic polyesters as a first component, and comprising a polyolefin or a mixture of polyolefins as a second component and comprising an effective amount of an excipient in the second component that improves the biodegradability of said polyolefin.

In another embodiment, the invention relates to textile sheets comprising the aforementioned bicomponent fiber.

Surprisingly, it was found that biodegradable fibers are formed that exhibit properties similar to polyolefin fibers, combining melt-spun polymers as a first component, for example, in the core of a bicomponent core-sheath fiber, and polyolefins with selected excipients as a second component, for example , in the sheath of a bicomponent fiber core-sheath.

DETAILED DESCRIPTION OF THE INVENTION

The polymer component of the core of the bicomponent fibers according to the invention is an aliphatic polyester or a mixture thereof. In addition, the first component may contain additives, such as fillers, pigments, matting agents, processing agents, antistatic agents or excipients to improve the biodegradability of microorganisms.

The aliphatic polyester of the first component is a biodegradable, synthetic, melt-spun polymer.

The term "biodegradable" is used in the present description to define a product that decomposes or decomposes under environmental conditions. Thus, a product is considered biodegradable from the point of view of this description if the decrease in tensile strength and / or peak elongation of said product is at least 50%, preferably at least 70% of their initial value, if subjected to accelerated aging test for six days using a dry chamber at 80 ° C. Such a test procedure for a biodegradation process is described in US patent 2007/0243350 A1.

The polymer of the first component is obtained from an aliphatic component having one carboxyl group (or its derivative forming a polyester, such as an ester group) and one hydroxyl group (or its derivative forming a polyester, such as an ether group), or obtained from a combination an aliphatic component having two carboxyl groups (or its derivative forming a polyester such as an ester group) with an aliphatic component having two g droksilnymi groups (or a derivative thereof, forming the polyester, such as an ether group).

The term "aliphatic complex polyester" covers, along with complex polyesters, which are made from aliphatic and / or cycloaliphatic components, exclusively also polyesters which contain, along with aliphatic and / or cycloaliphatic units, aromatic units, as long as they do not affect adversely on the biodegradability of these polyesters.

Polymers derived from an aliphatic component having one carboxyl group and one hydroxyl group are alternatively referred to as polyhydroxyalkanoates (PHA). Examples thereof are polyhydroxybutyrate (PHB), poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly (hydroxybutyrate-co-hydroxyhexanoate) (PHBG), polyglycolic acid (PGC), poly (epsilon-caprolaction) (PCL) and preferably polylactic acid (PMA).

Examples of polymers obtained from the combination of an aliphatic component having two carboxyl groups with an aliphatic component having two hydroxyl groups are polyesters derived from aliphatic diols and from aliphatic dicarboxylic acids, such as polybutylene succinate (PBSU), polyethylene succinate, polyethylene succinate, (PBA), polyethylene adipate (PEA), poly (tetramethylene adipate terephthalate) (PTMAT).

The polymer component of the second component of the bicomponent fiber according to the invention is a polyolefin or a mixture thereof. In addition, the specified second component should contain at least an effective amount of excipient, which improves the biodegradability of the polyolefin. In addition, the second component may contain other additives, such as fillers, pigments, matting agents, processing aids and / or antistatic agents.

The polyolefins used as the material of the second component are usually derived from alpha olefins. Examples of polyolefins are any form of polyethylene (PE), such as low density polyethylene (LDPE), high density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE) and polyethylene ultra-low density (ULDPE), or polypropylene (PP) in any form, poly (1-butene), poly (1-pentene) or poly (4-methylpent-1-ene). In addition to homopolymers, copolymers are also included. Examples thereof are copolymers of ethylene with one or more copolymerizable alpha olefins, copolymers of propylene with one or more copolymerizable alpha olefins, preferably copolymers of ethylene and / or propylene with higher 1-olefins, such as 1-butene, 1-pentene, 1 -hexene, 1-heptene, 1-octene, 4-methylpent-1-ene or 1-decene.

Further representatives of the polyolefins are mixtures of polyolefins and / or polyolefins which contain sites obtained by grafting unsaturated monomers with a double bond onto a polyolefin base.

The polyolefin of the second component contains an auxiliary substance that promotes the biodegradation of the specified polyolefin. These excipients are known to those skilled in the technology, as highlighted in the section "Level of invention".

Preferably, Envirocare (Envirocare (Ciba)), Addiflex (Addiflex (Add-X Biotech AB)) and ECM 6.0204 (ECM Biofilms) products may be used.

The bio-degradable excipient of the polyolefin preferably contains a microbial nutrient, preferably starch, an inorganic particulate compound such as calcium carbonate, and a transition metal salt such as iron, manganese, cobalt or copper carboxylate. Examples of such excipients are found in US patent 2007 / 0243350A1.

The amount of excipient that promotes the biodegradation of the polyolefin can vary widely. Because commercial considerations usually use as low quantities as possible to ensure that the desired degree of biodegradability of the polyolefin is obtained. If a higher amount of this excipient is used, the upper limit is set by the spinning process used in the formation of the bicomponent fiber. Thus, any amount of this excipient can be used, as long as it does not slow down the process of fiber formation.

The preferred excipient used in the bicomponent fiber production method of this invention is used as a masterbatch (concentrate) with a polyolefin as a carrier polymer.

The amount of masterbatch used in the fiber production method of this invention is within the range of 0.5-10% by weight, preferably 1-6% by weight, more preferably 3-5% by weight, based on the total number of sheath forming components .

Concentrations of excipients promoting the biodegradation of the polyolefin within the specified masterbatch are within the range of 0.075-1.5 wt.%, Based on the total number of masterbatch.

A preferred masterbatch used in the fiber production method of the invention contains 25-85 wt.% Polyolefin and a biodegradation aid that includes 1-30 wt.% Starch, 2-50 wt.% Calcium carbonate and 0.5-15 wt.% metal salt. Interest refers to the full composition of the masterbatch.

The total amount of excipient promoting the biodegradation of the polyolefin in the second component is usually within the range of 0.005-0.5 wt.%, Preferably 0.01-0.3 wt.%, More preferably 0.03-0.25 wt. .%, calculated on the total number of components forming the second component.

Preferred bicomponent fibers of the invention have a first component, a PMA polymer, preferred as a core-sheath fiber core.

Further, preferred bicomponent fibers of the invention have a second component, polyethylene and / or polypropylene, preferred as a core-sheath fiber sheath.

In another preferred embodiment according to the invention, the biodegradability aid of the polyolefin comprises starch and a salt of a transition metal compound.

In a further preferred embodiment according to the invention, the first component of the bicomponent fiber comprises a filler, preferably an alkaline earth metal carbonate, particularly preferably calcium carbonate.

The bicomponent fibers of the invention may be infinite fibers (filaments) or fibers of finite length (staple fibers). The bicomponent fibers of this invention typically have denier between 1 and 10 dtex (decitex). But it doesn’t matter, and smaller or higher denier can be provided. Preferred fiber diameters are greater than 10 microns, preferably between 10 and 20 microns.

The bicomponent fibers of the invention may contain various polymer sites in any form. Examples have a core-shell, side-by-side or island-in-sea configuration. Core-shell configurations are preferred.

The bicomponent fibers of the invention may have a cross section of any shape. Examples of cross sections are found in the book “Fibers, 2. Structure” (Ullmann Encyclopedia); Hearle J., “Fibetrs, 2. Structure” (Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH: 2002, 1-85). Examples of preferred cross-sections are circular, ellipsoidal, tri-or multi-angle or tri-longitudinal or multi-longitudinal.

The amounts of the first component and the second component can vary widely. The intervals of the first component are from 10 to 90 wt.%. The intervals of the second component are from 90 to 10 wt.%. These percentages refer to the total amount of fiber. Preferably, the amount of the first component is higher than the amount of the second component, for example, 55-90 wt.% Of the first component, such as the core, and 45-10 wt.% Of the second component, such as the shell.

The bicomponent fibers of the invention can be converted into textile sheets or into other forms of fiber strands, such as secondary staple yarns or cords.

A textile sheet comprising fibers of the invention may be of any nature. Examples of this are fabrics, knitwear, knitted fabrics, nets, clutches, or preferably non-woven materials.

The textile sheets of the invention may be in the form known to those skilled in the art. Non-woven materials, for example, can be formed by wet laying or dry laying. Examples of these methods are carding processes for the production of carded fabric and spunbond processes for the formation of spanbond materials (spunbond). These latter nonwovens are preferred.

The production of textile sheets according to the invention usually includes the following stages:

a) subjecting the bicomponent fiber of this invention and, optionally, together with other strands, such as staple fibers or yarns, to textile technology for forming sheet materials to obtain a primary textile sheet, and

b) optionally subjecting said primary textile sheet to stabilization treatment known in the art.

Depending on the type of textile technology for forming sheet materials, such as weaving or knitting, a sufficiently stable primary textile sheet is obtained. In this case, step b) is optional, but may be performed. Thus, in these cases, the primary textile sheets can represent the final textile sheets.

In other types of textile technology for forming sheet materials, such as the formation of nonwoven materials, usually, the resulting primary textile sheet is not sufficiently stabilized. In most of these cases, step b) is mandatory. Thus, in these cases, the primary textile sheets must be further processed to lead to the final textile sheets.

In addition to non-woven materials, including or consisting of fibers according to this invention, layers of non-woven materials made from other materials may be present. These multilayer nonwoven materials also form the subject of the present invention.

In addition, the textile sheets along with the fibers of the invention may contain additional strands made of other materials, such as other polymers. These additional strands made of other materials may be present in any form, such as staple fibers, threads or yarn. Examples of polymers forming such additional strands are cellulose, starch, proteins and / or synthetic polymers such as polyesters, polyamides or polyacrylonitrile.

The primary textile sheets described above can or should be stabilized after the sheet forming process in a known manner. This stabilization treatment may be mechanical processing by the action of needles and / or hydroweaving, or it may be stabilization by gluing the fibers forming the primary textile sheet, for example by adding adhesive to the primary textile sheet, and / or heat treatment of the primary textile sheet to cause the fibers to stick together and / or any fiber binder components that may be further included in said primary textile sheet.

Other known methods for processing textile sheets can be performed during or after their production. For example, textile sheets can be subjected to printing processing, or textile sheets, preferably non-woven materials, can be embossed on at least one of their surfaces, for example, by the action of a profiled calendering drum to give a surface pattern and additional curing of selected parts of the textile sheet caused by the adhesion of a melt of elementary fibers in places of processing a textile sheet.

One advantage of the bicomponent fibers of this invention is that they can be processed with sheet forming techniques known from the production of polyolefin textile sheets without changing process parameters in connection with known sheet production methods.

The textile sheets of the present invention typically have a specific gravity of 10-200 g / m ² , preferably 15-50 g / m ² .

The textile sheets of the present invention can be used for personal care applications, for example, baby care products (diapers, wipes), for women (pillows, sanitary towels, tampons), for adults (incontinence products), or for cosmetic applications (pillows )

The invention also relates to the use of the aforementioned textile sheets in medical applications, for example, as protective clothing or as an operating coating, or in cleaning products. In addition, the aforementioned textile sheets can be used in filtration products, for acoustic protection, in automotive applications, as geotextiles, as a coating in agriculture, as a plant propagation pot, as non-woven materials for sheets including seeds and / or nutrients, as a bag, for example, as a shopping bag or as frost protection.

The following examples explain the invention without limiting it.

Comparative Example 1

A nonwoven material was obtained by melt-spinning two-component fibers with a core-sheath configuration and spunbond formation with a basis weight of 15 g / m ² in a pilot plant. The core weight is 75% and the shell weight is 25%. The core was made of PMK, and the shell was made of polypropylene. Neither the core nor the shell contained additives.

Comparative Example 2

Follows the methodology of Comparative Example 1, but produce spanbond with a basis weight of 26 g / m ² .

Comparative Example 3

Follows the procedure of Comparative Example 1, but 10% by weight calcium carbonate (Omyalene 102M) based on the weight of the core is used in the PMC core.

Comparative Example 4

Follows the methodology of Comparative Example 1, but produce spanbond with a basis weight of 26 g / m ² .

Example 1

A nonwoven material was obtained by melt-spinning two-component fibers with a core-sheath configuration and spunbond formation with a basis weight of 15 g / m ² in a pilot plant. The core weight is 75% and the shell weight is 25%. The core was made of PMK, and the shell was made of polypropylene. The core contained 10% by weight, based on the weight of the core, calcium carbonate (Omyalene 102M). The casing contained 3% by weight based on the weight of the casing, a biodegradation promoter (Addiflex HE).

Example 2

It follows the procedure of Example 1, but produce spanbond with a basis weight of 26 g / m ² .

The following table summarizes the spunbond data prepared in Comparative Examples 1-4 and in Examples 1-2.

Example Core material Additive core ^one)  (the weight.%) Sheath material Additive Shell ^one)  (the weight.%) Base weight (g / m ² ) C1 PMK Calcium Carbonate (10) PP - fifteen C2 PMK Calcium Carbonate (10) PP - 26 C3 PMK Calcium Carbonate (10) PP - fifteen C4 PMK Calcium Carbonate (10) PP - 26 one PMK Calcium Carbonate (10) PP Decomposition promoter (3) fifteen 2 PMK Calcium Carbonate (10) PP Decomposition promoter (3) 26 ¹⁾ Omialn 102M (Omia) ²⁾ Addiflex NOT (Add-X)

Decomposition Tests

To test the decomposition of nonwoven samples, a thermal aging test was performed. The heat aging test was recommended by Add-X (supplier of Addiflex additives) and compares well with composting tests.

Samples of nonwoven materials were cut to perform tensile and elongation tests and samples were placed in a dry chamber at 80 ° C. After several days of treatment, tensile properties were measured.

The results are shown in the following tables.

Example PR / MN ^one)  before processing (N) PR / MN ^one)
across
1 day
term-
processing (N) PR / MN ^one)
across
2 days term
processing (N) PR / MN ^one)
across
4 days term
processing (N) PR / MN ^one)  across
6 days heat treatment (N) PR / MN ^one)  across
10 days term
processing (N) C1 thirty 29th 28 thirty 28 29th C2 67 67 66 66 64 66 C3 fourteen 13 13 fourteen 13 fourteen C4 31 32 32 31 thirty 31 one 12 12 eleven eleven 2 one 2 31 31 32 thirty 10 four ¹⁾ Machine tensile strength, PR / MN

Example Elongation at peak load before processing (%) Elongation at peak load after 1 day of heat treatment (%) Elongation at peak load after 2 days of heat treatment (%) Elongation at peak load after 4 days of heat treatment (%) Elongation at peak load after 6 days of heat treatment (%) Elongation at peak load after 10 days of heat treatment (%) C1 58 44 42 42 43 40 C2 65 51 51 49 fifty 49 C3 25 19 19 twenty 19 eighteen C4 40 31 thirty 29th 28 28 one 24 twenty eighteen eighteen 2 one 2 38 29th thirty 28 four 2

The discussion of the results

Spunbond (non-woven synthetic fabric) obtained from two-component fibers PMK-PP, showed tensile strength, which remained almost unchanged during heat treatment. The elongation values immediately decreased within one day, but remained virtually unchanged afterwards.

Spunbonds obtained from bicomponent PMK-PP fibers and containing a filler of calcium carbonate in the core showed the same behavior as unfilled samples. But the addition of filler greatly reduced the tensile strength and elongation of the untreated samples.

Spunbonds obtained from PMK-PP bicomponent fibers and containing a filler of calcium carbonate in the core and containing an auxiliary decomposition accelerator substance in the shell showed the same tensile strength and elongation properties as filled samples prior to heat treatment. After heat treatment for 4 days or more, the tensile and elongation strengths decreased significantly, indicating that the spunbond was deteriorating. Finally, some of these samples disintegrated upon contact.

These results demonstrate that it is possible to obtain a fully biodegradable bicomponent nonwoven fabric PMK-PP showing the tensile properties of known nonwoven materials.

Claims (16)

1. A bicomponent fiber having denier between 1 and 10 dtex and comprising an aliphatic polyester or a mixture of aliphatic polyesters as a first component, and comprising a polyolefin or a mixture of polyolefins as a second component, and comprising in the second component an effective amount of an auxiliary substance that improves the ability to biodegradation of said polyolefin. 2. The bicomponent fiber according to claim 1, which is in the configuration of the core-shell, in which the first component forms the core, and the second component forms the shell. 3. The bicomponent fiber according to claim 1, wherein the first component is made from polylactic acid. 4. The bicomponent fiber according to claim 1, wherein the second component comprises polyethylene or polypropylene. 5. The bicomponent fiber according to claim 1, wherein the biodegradable excipient of said polyolefin comprises starch and a salt of a transition metal compound. 6. The bicomponent fiber according to claim 1, wherein the first component comprises an alkaline earth metal carbonate, preferably calcium carbonate. 7. A textile sheet comprising a bicomponent fiber according to claim 1. 8. The textile sheet of claim 7, wherein said textile sheet is a nonwoven material. 9. The textile sheet of claim 8, wherein the non-woven material is spunbond. 10. The textile sheet according to claim 7, in which, in addition to the bicomponent fibers, other fibers are present, preferably fibers selected from the group of polyolefin fibers, viscose fibers, polyester fibers and polyamide fibers. 11. The use of bicomponent fiber according to claim 1 in a personal care product. 12. The use of a textile sheet according to claims 7-10 in a personal care product. 13. The use according to claim 11, in which the personal care product is a diaper, wiping, pillow, sanitary towel or tampon. 14. The use according to claim 12, wherein the personal care product is a diaper, wiping, pillow, sanitary towel or tampon. 15. The use of the bicomponent fiber according to claim 1 for medical use, in cleaning products, in filtration, for acoustic protection, in automotive applications, as geotextiles, as an awning in agriculture, as a plant propagation pot, as a non-woven sheet material, including seeds and / or nutrients, like a bag or as a coating to protect against frost. 16. The use of a textile sheet according to claim 7 for medical use, in cleaning products, in filtration, for acoustic protection, in automotive applications, as geotextiles, as an awning in agriculture, as a plant propagation pot, as a non-woven material for sheets, including seeds and / or nutrients, like a bag or as a coating to protect against frost.