RU2444583C2 - Multicomponent fibre - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: multicomponent fibre contains at least two elongated fibre bodies, where the first fibre body consists of a first material containing a phase change material, and the second fibre body consists of a second material and surrounds the first fibre body. The phase change material is in an initial form. The first material contains a viscosity modifier selected from polyolefins having density in the range of 890-970 kg/m³, determined at room temperature according to ISO 1183-2, and melt flow rate in the range of 0.1-60 g/10 min, determined at 190°C with a load of 21.6 kg according to ISO 1133.

EFFECT: high latent heat and strength of the fibre.

24 cl, 8 dwg, 11 tbl, 6 ex

Description

The present invention relates to multicomponent fibers containing phase transition material, to textile materials and fabrics (e.g., knitted fabrics, woven and nonwoven fabrics) containing multicomponent fibers, and to absorbent articles containing multicomponent fibers.

The human thermoregulation system aims to maintain a constant body temperature and skin temperature in an interval that is different in different parts of the body. Comfortable skin temperatures are in the range of 28-33ºC. Outside the specified interval, the human body is uncomfortable.

The human body regulates the rate of heat exchange with the environment by regulating the blood flow of the skin. Sweat (heat loss by evaporation) or chills (heat) results in large deviations in body temperature.

The ability and effectiveness of the human thermoregulation system is quite limited. Putting on or removing clothes helps the body stay within comfortable temperatures at various levels of activity and environmental conditions for long periods of time. However, it is not always appropriate or possible to wear or remove clothing in a culturally acceptable manner, or it may be physically impossible or difficult. This applies in particular to clothes like underwear or absorbent articles. Clothing and absorbent products with built-in temperature-regulating properties are able to maintain comfort without putting on or taking off clothes. Such clothes and absorbent products reduce the discomfort caused by the accumulation of sweat / moisture, as well as chills, which is quite unpleasant.

The integration of phase transformation materials ((MFP) (PCM)) into clothing is one way to achieve thermoregulating properties. When skin temperature rises, the MFP melts and absorbs the heat released from the skin. Then, when the temperature drops, the MFP crystallizes and the stored heat is released again. Thus, fluctuations in skin temperature can be suppressed, and the temperature is maintained in a comfortable area. Not only products in the form of clothing and absorbent products can benefit from the introduction of MFPs, but also textile materials used, for example, for bedding, pillowcases, blankets, furniture, car seats and shoes.

MFP-introducing textile materials can also be used in residential and institutional applications, such as carpets and drapes, to even out temperature fluctuations between day and night and therefore reduce energy costs for heating (night time) and air conditioning (day time) )

The most used method of introducing MFP into textile materials is to coat the tissues with a polymer binder containing MFP in microcapsules. The effect of thermal control is determined by the mass of the coating. In addition, the number of microcapsules that can be introduced into the coating is limited, so that the effect of thermal control is limited. In addition, the use of microencapsulated MFP as part of the coating has several disadvantages, in addition to the above problems and the high cost of microcapsules. Properties like air permeability and moisture permeability deteriorate, which negatively affects thermal comfort. In addition, the increase in the introduction to the coating gives a stiff and less elastic fabric, which is less comfortable to wear. Also, by the presence of a coating, surface properties like wetting can be impaired. This is especially important when it comes to training sportswear or absorbent products, since the desired property of such products is the ability to transport human body fluids to the surface of the fibers.

The disadvantages associated with coatings can be avoided by introducing MFP microcapsules into the fibers. The input gain is that microcapsules are more reliably bonded to the fibers and can withstand washing. The introduction of microcapsules is possible in acrylic fibers spun from a solution and cellulose fibers spun from a solution, but the thermal efficiency is quite low (less than about 10 to 30 J / g), since the amount of MFP that can be introduced is limited by factors such as spinnability and sufficient fiber strength.

The predominant synthetic fiber used today is polyester, which is obtained by melt spinning. The introduction of microcapsules into standard melt-spun fibers is still limited for several reasons. Microcapsules must be able to withstand high temperatures and shear forces occurring in the melt spinning process. Other reasons are capsule size (1-10 microns) and the fact that the particulate filler will extremely increase the melt viscosity, making melt spinning of thin fibers very difficult.

Upon receipt of fibers with the content of the MFP, the task is to obtain the highest possible temperature-controlled effect on the unit load of the MFP. In order to achieve a quick exchange of energy between the skin of the human body and the MFP introduced into the fiber, any unnecessary interference should be minimized. In addition, in order for the MFP content to be as high as possible in the fibrous material, any excess component of the material should be minimized.

If MFP is to be used in melt-spun fibers without being microencapsulated, i.e. in its original form, it must be closed in fiber. The solution is to use multicomponent fibers with a core / cladding structure or the so-called island-in-sea structure, so that the MFP is trapped inside the fibers. However, a number of difficulties must be overcome.

In “Effect phase change material content on properties of heat-storage and thermo-regulated fibers nonwoven”, Indian Journal of Fiber & Textile Research, Vol. September 28, 2003, pp. 265-269 describes a method for spinning fibers containing phase transformation material in its original form. The core / sheath fibers were melt spun with n-eicosan (as MFP) and a mixture of polyethylene and ethylene-propylene copolymer in the core. The shell was made of polypropylene. The tested maximum MFP content was 21 wt.%, And the latent heat of fibers 32 J / g was achieved. However, only about 50-60% of the theoretically possible latent heat was realized, indicating that a significant part of the MFP in the fiber core is not involved in melting / crystallization.

In addition, WO 02124992 A1 discloses that MFP in its original form is used in spinning fibers. But the examples show phase transformation material not encapsulated in microcapsules, and examples with unencapsulated phase transformation material are not considered.

WO 2006/086031 A1 describes the use of modified forms of ethylene-propylene copolymers and polar copolymers (for example, a copolymer of ethylene and vinyl acetate) to facilitate dispersion of the phase transformation material in the core material. Fibers having a high phase transformation material content and high latent heat values are not considered.

No. 7,160,612 B2 also discloses that MFP in its original form can be used in spinning fibers. Latent heat and fiber strength are unsatisfactory.

US 2007/0089276 A1 describes melt-spun multicomponent fibers introducing MFP in its original form. Latent heat is not considered.

US 7241497 A1 discloses a multicomponent fiber containing a temperature-controlled material dispersed therein. Latent heat and fiber strength are unsatisfactory.

Phase conversion polymer materials are also used for spinning fibers, but although such a phase conversion material has a higher viscosity than low molecular weight hydrocarbon waxes, and therefore mixing with a viscosity modifier is not required, they are not very effective because they have fairly low latent heat values.

Thus, there is a need for fibers containing high amounts of phase transformation material, where the fibers have high latent heat combined with good mechanical strength. Such fibers have not yet been described.

Thus, there is a need to develop multicomponent fibers containing phase transformation material, with good latent heat effect and high strength. The aim of the present invention is to solve the above problems.

The present invention relates to a multicomponent fiber containing at least two elongated fiber bodies, where the first fiber body consists of a first material containing phase transformation material, and the second fiber body consists of a second material and surrounds the first fiber body. The phase transformation material is unencapsulated or in its original form, and the first material contains a viscosity modifier selected from polyolefins having a density in the range of 890-970 kg / m ³ as measured at room temperature according to ISO 1183-2, and the melt flow rate in in the range of 0.1-60 g / 10 min, as measured at 190ºC with a load of 21.6 kg according to ISO 1133.

In addition, the present invention relates to a textile material containing multicomponent fibers.

A fabric containing multicomponent fibers is also contemplated according to the present invention.

In addition, the present invention relates to an absorbent article containing multicomponent fibers.

The invention is illustrated in the drawings, where:

in figures 1 a) -d) shows a cross section of various variants of multicomponent fibers according to the present invention.

In figures 2 and 3 shows a cross section of other variants of multicomponent fibers according to the present invention.

Figure 4 shows a sanitary napkin according to an embodiment of the present invention.

The figure 5 presents a cross section of a sanitary napkin from figure 4.

Figure 6 schematically shows a cross section of the downstream portion of a die for bicomponent core / sheath fibers.

7 is a diagram of a typical method for producing a multicomponent fiber according to the present invention.

The figure 8 presents a graphical dependence of the complex viscosity at 190ºC and 10 rad / s from wt.% RT27 for various mixtures of polyethylene and RT27. RT27 is a paraffin wax obtained by Rubitherm GmbH, Berlin, Germany.

Definitions

The degree of drawing (DR) is defined as the ratio of speed (V2 / V1) in the drawing method in the solid state, i.e. DR = V2 / V1. V1 represents the speed of the filament after drawing the melt. V2 is the speed after drawing in the solid state.

For this material composition, the titer is an indirect measure of the diameter of the filament and is expressed in units of g / 1000 or 10,000 m of filament (tex or dtex, respectively).

Tear resistance is a measure of the strength of the filament (the maximum force held by the filament during the tensile test divided by the titer of the filament) and is expressed in units of cN / tex.

The modulus of elasticity is a measure of the stiffness of the filament and is calculated as the force at 1% strain divided by the titer of the filament and is expressed in units of cN / tex.

MFR melt flow rate is the inverse of the molecular weight of a polymer. Those. for a given polymer, MFR decreases with increasing molecular weight.

MFP efficiency here means the ratio obtained by dividing the heat of fusion of the first material containing MFP by the heat of fusion of pure MFP and the mass fraction of MFP in the first material containing MFP. MFP efficiency is expressed as a percentage and calculated using the equation:

MFP efficiency = ΔH _{cm /} (w _MFP · ΔH _MFP ) · 100,

where ΔH _cm is the measured heat of fusion of the first material containing MFP (MFP + viscosity modifier), w _MFP is the mass fraction of MFP and ΔH _MFP is the measured heat of fusion of pure MFP.

Here, thermal efficiency is understood as the ratio obtained by dividing the heat of fusion of a multicomponent fiber by the heat of fusion of pure MFP and the mass fraction of MFP in a multicomponent fiber containing MFP. Thermal efficiency is expressed as a percentage and is calculated using the equation:

Thermal efficiency = ΔH _{fiber /} (w _MFP · ΔH _MFP ) · 100,

where ΔH _fiber is the measured heat of fusion of a multicomponent fiber containing MFP, w _MFP is the mass fraction of MFP and ΔH _MFP is the measured heat of fusion of pure MFP.

A textile material is an elastic material consisting of a network of natural and / or artificial fibers, often called threads or yarns. The yarn is obtained by spinning the original woolen fibers, linen, cotton or other material on a spinning disk to produce long strands known as yarn. Synthetic yarn is also available in the form of filament yarn. Textile materials are molded by weaving, knitting, crocheting, knitting or knitting fibers together. Textile materials can be made of many materials. These materials come from four main sources: animal, vegetable, mineral and synthetic.

The fabric is a textile material. The word “fabric” is commonly used in textile industries (such as designing and sewing clothes) as a synonym for textile material. However, there are subtle differences in these terms. "Textile material" refers to any material made of interwoven fibers. “Fabric” refers to any material made by weaving, knitting, crocheting or stapling. It can usually be said that fabrics are fiber-containing products having a significant surface occupying space relative to their thickness. Nonwoven products are also included in this definition.

Non-woven fabrics are fabrics that are neither woven nor knitted, for example, canvas. They are usually made by laying staple fibers together in the form of a sheet or canvas and then fastening them mechanically (as in the case of the canvas when weaving them with serrated needles, so that the interfiber friction results in a strong fabric), glue or thermally (using a binder (in the form of powder , paste or polymer melt) and melting the binder on the canvas with increasing temperature). Another manufacturing technique involves direct thermal bonding of melt-spun fibers. Melt spun nonwovens are produced in one continuous process. The fibers are spun and then directly distributed in the canvas by reflectors, or they can be directed by air currents. Several options for this approach are available. Melt-spun nonwoven materials are combined with nonwovens obtained by the aerodynamic method, together forming them into a layered product called SMS (melt-spun — aerodynamically spun-melt). Aerodynamically spun nonwovens have fibers of extremely thin diameters, but are not durable fabrics. Melt spun nonwovens are thermally bonded or resin bonded.

In the following, the expression “core material” is sometimes used instead of the expression “first material”, and the expression “sheath material” is sometimes used instead of the expression “second material”.

The expression "initial form" is intended to mean that in the manufacture of multicomponent fibers, the MFP is introduced in its original form, i.e. The MFP is not encapsulated, the MFP is not transferred onto or by other material that is solid at the die temperature during spinning of a multicomponent fiber, as it impregnates a porous structure, where the structure is solid at a die temperature during spinning of a multicomponent fiber. Thus, it is believed that the MFP is in its "original form" despite the fact that it is mixed with a viscosity modifier in the manufacture of multicomponent fibers.

The present invention relates to multicomponent fibers having thermoregulation properties by introducing phase transformation material.

Multicomponent fibers thus have the ability to absorb and release heat while maintaining a constant temperature. Multicomponent fibers can be used in various products to ensure thermoregulatory properties. Products, such as clothing or absorbent products worn close to or in contact with the skin of the user, give the user a comfortable feeling. If, for example, a part of the garment or the upper layer of the absorbent article contains multicomponent fibers according to the present invention, the garment or article can even out fluctuations in skin temperature so that it is maintained in a comfortable area. When worn near the user's body, multicomponent fibers will contribute to a comfortable sensation of the user during various physical activities, fluctuations in environmental conditions or when the skin temperature undergoes fluctuations in normal temperature due to, for example, emotional impact or during the circadian rhythm. If the top layer in the absorbent article contains multicomponent fibers according to the present invention, the article can absorb heat from the user, causing the user to sweat less.

This is particularly preferred if a dense product with low vapor transmission is used in contact with the user's body in order to avoid moisturizing the user's skin. Moisture on the skin of the user is a problem in terms of both absorbent products and textile materials, which can lead to skin problems.

The present invention, therefore, relates to a multicomponent fiber 10, as shown in figure 1, containing at least two elongated fiber bodies 11, 12, where the first fiber body 11 consists of a first material containing phase transformation material, and a second body fiber 12 consists of a second material and surrounds the first fiber body 11, where the phase transformation material is in its original form and the first material contains a viscosity modifier selected from polyolefins having a density in the range of 890-970 kg / m ³ as defined but at room temperature according to ISO 1183-2, and the melt flow rate in the range of 0.1-60 g / 10 min, determined at 190ºC with a load of 21.6 kg according to ISO 1133.

The expression "initial form" means that the MFP is introduced in its original form in the manufacture of multicomponent fibers, i.e. Since the MFP is unencapsulated, the MFP cannot be transferred onto or by other material that is solid at the die temperature during spinning of a multicomponent fiber, as it impregnates a porous structure, where the structure is solid at a die temperature during spinning of a multicomponent fiber. Thus, it is believed that the MFP is in its "original form" despite the fact that it is mixed with a viscosity modifier in the manufacture of multicomponent fibers.

It was found that polymers having a melt flow rate in the range of 0.1-60 g / 10 min, determined at 190 ° C. under a load of 21.6 kg, are suitable as viscosity modifiers in a multicomponent fiber. Many of the effective MFP materials are low molecular weight compounds, and such compounds have low viscosity at the considered processing temperatures (180-300ºC). In order to obtain multicomponent fibers with a sheath material, the second material having a higher viscosity at the processing temperature, the inventors have now found that if the phase transformation material is mixed with a polyolefin having a melt flow rate in the range of 0.1-60 g / 10 min., a fiber is obtained having high latent heat and which is durable. Polyolefin is a viscosity modifier that increases the viscosity of the first multicomponent fiber material. It has been found that a low amount of viscosity modifier can be used having a melt flow rate in the range of 0.1-60 g / 10 min, which is an advantage for thermal efficiency in terms of specific latent heat and at the same time ensures full use of internal specific latent heat of fusion / crystallization of the material of the phase transformation. If a value above 60 g / 10 min is used, the viscosity will be too low and the mixture will not be able to be processed into fiber. The mixture will be “watery”, i.e. very liquid. A value lower than 0.1 g / 10 min viscosity modifier can lead to twisting of the fibers, and it may be impossible to spin the fiber.

Other disadvantages associated with the use of low viscosity materials in melt spinning, such as backflow and leakage in screw extruders and gear pumps, are also prevented by mixing the phase transformation material with a polyolefin having a melt flow rate in the range of 0.1-60 g / 10 min Then the first material has a viscosity high enough to be processed at the process temperature.

In addition, the viscosity modifier may have a density of more than 920 kg / m ³ , preferably more than 950 kg / m ³ , determined at room temperature according to ISO 1183-2.

The phase transformation material is compatible with the melt viscosity modifier, although it is released into the pure phase upon cooling. It is preferable to use a viscosity modifier with a high density. The modifier effect will be higher and a lower amount will be required. This gives a more efficient use of the internal specific heat of fusion per gram of phase transformation material. Can be obtained such a high efficiency of the MFP, as 90% or more, as described in example 2.

The viscosity modifier may have a melt flow rate in the range of 0.1-50 g / 10 min, preferably 0.1-20 g / 10 min, more preferably 0.1-10 g / 10 min, as determined at 190 ° C. under a load of 21, 6 kg according to ISO 1133. The lower the melt flow rate used for the viscosity modifier, the lower the viscosity modifier required to bring the viscosity of the first material containing the phase transformation material to a level adequate for processing the first material into a multicomponent fiber. This is also shown in Example 1 below. In addition, in Example 1, it was considered that an MFR below 10 g / 10 min is sufficient to reduce the viscosity modifier concentration in the first material to less than about 30 wt.% With an increase in viscosity in the range of standard polymer grades used for spinning fibers from the melt. The first material may further comprise additives that are conventional for use in the manufacture of fibers. In addition, a compatibilizer may be included in the first material in order to improve the boundary layer between the first fiber body and the second fiber body.

The phase transformation material may have a latent heat of at least 100 J / g and preferably at least 140 J / g. The indicated values are good for obtaining fibers having latent heat, which is effective and which gives thermoregulatory effects.

In addition, the first MFP containing material may have an MFP efficiency as defined by the ratio ΔH _{mixture /} (w _MFP · ΔH _MFP ) · 100, which is at least 90, expressed in%, preferably at least 95 % High MFP efficiency means that MFP is used in an efficient manner. High efficiency is provided, for example, by the density of the viscosity modifier and the MFR viscosity modifier.

In addition, the multicomponent fiber containing the phase transformation material may have thermal efficiency as defined by the ratio ΔH _{fiber /} (w _MFP · ΔH _MFP ) · 100, which is at least 60, expressed in%, preferably at least 70%, more preferably at least 75%.

High thermal efficiency means that the MFP is used in an efficient manner. High efficiency is provided, for example, by the density of the viscosity modifier, the MFR viscosity modifier and the choice of the second material.

In addition, the viscosity modifier is present in an amount of less than 50 wt.%, Preferably less than 40 wt.% And more preferably less than 30 wt.%, Calculated on the total weight of the first fiber body. When the amount of viscosity modifier can be kept low, high latent heat can be obtained in the core. This may depend on the MFR value and viscosity modifier density.

In order to obtain high latent heat, the MFP may be present in an amount of more than 50 wt.%, Preferably more than 60 wt.% And more preferably more than 70 wt.%, Calculated on the total weight of the first fiber body.

The first material contains phase transition material and a viscosity modifier in an amount of at least 90 wt.% Together, calculated on the total weight of the first material. The inventors have found that in order to obtain fibers, it is necessary that there are no unnecessary elements in the first material. This is possible since there is no need for encapsulated materials or other supporting materials, such as porous structures, in which MFP is absorbed.

According to the present invention, the phase transformation material is selected from hydrocarbon waxes with a melting point in the range of 20-50 ° C, preferably in the range of 25-45 ° C, and more preferably in the range of 27-40 ° C. The indicated temperatures are suitable when considering the thermoregulatory material used to thermoregulate the medium near or in close contact with human skin.

The phase transformation material is selected from linear hydrocarbon waxes. Preferred hydrocarbon waxes are n-octadecane, n-nonadecane, n-eicosan, n-geneukosan, or mixtures thereof. These waxes have melting points that are suitable according to the present invention. These hydrocarbon waxes have a heat of fusion of about 200 J / g in their pure form. However, for economic reasons, it may be preferable to use less pure materials having lower heat of fusion, but which are much cheaper.

The viscosity modifier may be polyethylene. The viscosity modifier is soluble in the phase transformation material at temperatures above the melting point of the viscosity modifier, which is polyethylene. In addition, very good results are obtained for multicomponent fibers containing a polyethylene viscosity modifier. Polyethylene may have a density of more than 950 kg / m ³ . This is good for phase separation of the phase transformation material from the viscosity modifier, as discussed above.

The multicomponent fiber has a latent heat of at least 20 J / g, preferably at least 30 J / g, and most preferably at least 40 J / g, as determined by the DSC method in the range of 0-50 ° C.

The fiber has a strength above 10 cN / tex, preferably above 15 cN / tex and most preferably above 20 cN / tex. The indicated strength values are very good for multicomponent fibers containing phase transformation material. Since high latent heat can be obtained in the core, i.e. in the first material, the core can make up a smaller part of the fiber and the sheath can be thicker, which makes the fiber more durable. Thus, the high efficiency of the latent heat of the MFP in the multicomponent fiber and the low concentration of the viscosity modifier in the first material in order to achieve adequate melt processing according to the present invention make it possible to obtain strong fibers.

According to the present invention, a multicomponent fiber is also considered in which the ratio between the viscosity of the first material and the second material meets the condition 0.1 <viscosity 1 / viscosity 2 <10, where viscosity 1 is the complex viscosity at an angular frequency of 10 rad / s of the first material containing MFP, and viscosity 2 is the complex viscosity at an angular frequency of 10 rad / s of the second material, where the viscosity is determined at the extrusion temperature used in the melt spinning process, i.e. at the set die temperature.

With the indicated ratio, it is possible to obtain multicomponent fibers in a spinneret. Under the above condition, problems associated with coextrusion, compression and pumping of devices such as screw extruders and gear pumps are prevented. Since the phase transformation material has a low viscosity, the viscosity modifier increases the viscosity of the first material, thus making it possible to achieve the above value and therefore making it possible to obtain multicomponent fibers. The choice of the MFP and the viscosity modifier and the second material in accordance with what is discussed in the present description, gives the considered ratio of viscosity.

The multicomponent fiber may also contain a second material, which is a fiber-forming polymer that does not dissolve in the phase transformation material at temperatures above the melting temperature of the fiber-forming polymer or softening temperature in the case of an amorphous polymer. The efficiency of the MFP can then be higher, since the MFP will be used to a higher degree, if not hindered by the presence of a second material dissolved in the material of phase transformation. If the second material does not dissolve in the phase transformation material, the phase transformation material does not dissolve in the second material. This avoids the problems related to the migration of low molecular weight MFP. Such problems can be smell, loss of MFP (also during washing / washing of objects containing multicomponent fibers) and sticky / greasy surfaces of fibers.

For all multicomponent fibers obtained in the examples, the thermal efficiency of multicomponent fibers is more than 70%, except when the second material is polypropylene. In fibers in which the second material is polypropylene, the efficiency is lower. However, such fibers are very good compared to fibers of this type that can be obtained today. Lower efficiency may depend on the fact that polypropylene can be dissolved in the phase transformation material. It can also lead to some leakage of the phase transformation material. This can be a problem for fabrics used, for example, in clothes that are washed and used for a long time. However, when fabrics are used in disposable products, this is not an inevitable problem.

For applications of the multicomponent fibers of the invention in objects that need to be washed regularly (for example, clothes and home textiles), it can be achieved that continuous migration of MFPs from fibers will greatly degrade their thermal efficiency over time and with washing cycles. For disposable products (e.g. wipes), MFP migration should not be an inevitable problem.

The second material may contain polymers selected from polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, a lactic acid polymer; polyamides such as PA-6, PA-66, PA-11 and PA-12; polycarbonate, polyoxymethylene, polyacrylates (e.g. PMMA), polyvinylidene difluoride or polypropylene. These polymers, in addition to polypropylene, do not dissolve in the phase transformation material, which is an advantage for the fibers. For example, migration and leakage of phase transformation material is prevented. Any of the preferred second materials may be combined with any of the preferred phase transformation materials and viscosity modifiers.

The fiber may comprise at least one or more first fiber bodies and at least one or more second fiber bodies. Any of the first materials and any of the second materials can be used in the first and second fiber bodies. The first materials may have a different composition, which the second materials may also have.

The present invention also relates to a textile material comprising a plurality of multicomponent fibers, as described herein. The textile material may have a latent heat of at least 10 J / g and preferably at least 20 J / g.

In addition, the present invention relates to a fabric containing multicomponent fibers, as described in the present description. The fabric may have a latent heat of at least 10 J / g and preferably at least 20 J / g.

In addition, the present invention relates to an absorbent article containing fibers, as a material containing many multicomponent fibers, as described in the present description. The fibers used in a textile material, fabric, or absorbent article may have any of the properties as discussed above.

Some variants of multicomponent fibers are shown in figures 1-3. Elongated fiber bodies can be arranged in various configurations. The core / sheath fibers, for example, are shown in Figure 1 a) -d), which shows a cross section of the fibers. Various multicomponent fibers 10, 20, 30 and 40 are shown. The first fiber body, i.e. a core 11, 21, 31 and 41 is shown surrounded by a second fiber body 12, 22, 32 and 42, i.e. a sheath which is surrounding and surrounds the core 11, 21, 31 and 41. However, other embodiments comprising more than one first fiber body and / or more than one second fiber body are also encompassed by the present invention. The figure 1 shows the round and three-petal cross-sectional shape of the fibers. According to the present invention, a number of other regular and irregular cross-sectional shapes are also encompassed by the present invention. Such forms can be, for example, oval, rectangular, square, multi-petal, pentagonal, trapezoidal, triangular, wedge-shaped, etc. In addition, the shape of the first fiber bodies may also be shaped as discussed for the fibers above.

The multicomponent fiber 10 in figure 1 a) will be described further below with the showing of all variants of figure 1 that are similar to each other. The first fiber body 11 is located in the fiber and is surrounded by the second fiber body 12. The first fiber body 11 consists of a material containing phase transformation material. The first core body of the fiber 11 is arranged concentrically with the second fiber body to form the sheath 12. A similar fiber is shown in FIG. 1 b), but the core 21 is larger than the core 11 in FIG. 1 a). The core 31 in FIG. 1 c) is eccentric with the second fiber body 32. The fiber 41 in FIG. 1 d) is tri-petal in shape.

The figure 2 presents a multicomponent fiber 50, in which the first bodies of the fiber 51 are located in the configuration of the island-in-sea. Thus, in this embodiment, more than one first fiber body is considered. A second fiber body 52 surrounds the first fiber bodies 51, which form “islands” in the second fiber body, i.e. "sea".

One or more additional fiber bodies surrounding the first fiber body, consisting of a material containing phase transformation material, may also be included in a multicomponent fiber according to the present invention. Additional fiber bodies may consist of the same or different material.

The multicomponent fiber 60 in FIG. 3 is an example that comprises at least a third fiber body in addition to at least one first fiber body and at least one second fiber body. The fiber comprises first fiber bodies 61 consisting of a first material and a second fiber body 62 consisting of a second material. In addition, the fiber contains third bodies of fiber 63, consisting of a third material. The third material may also contain phase transformation material and a viscosity modifier. In the first and third materials, various phase transformation materials and viscosity modifiers can be used. The third material may be selected according to characteristics as defined above for the first material. However, for the first and third materials used in the same multicomponent fiber, the characteristics are not the same. All of the above options may contain materials, as defined above for multicomponent fibers.

If the multicomponent fibers need to be stronger, additives such as nanoclay can be added to the second material. Nanoclay work as a hardening material. An additional advantage of introducing nanoclay into the second material is that the permeability of low molecular weight compounds can be reduced (winding path for diffusion), i.e. lower MFP migration through the second material.

Furthermore, the present invention relates to an absorbent article, such as a diaper, sanitary napkin, incontinence article, panty liner, protective layer, etc., comprising multicomponent fibers as described above. Multicomponent fibers can be used in a nonwoven material, for example, used as a top layer in an absorbent article. This gives a comfortable feeling to the user.

The absorbent article may comprise a non-woven material as an upper layer, where the non-woven material contains multicomponent fibers according to the present invention and, in addition, a lower layer and possibly intermediate layers, as described below. An embodiment in the form of a sanitary napkin 401 is shown in Figure 4, where the sanitary napkin contains a nonwoven fabric containing the multicomponent fibers of the present invention as the top layer 402. Also included is a bottom layer, which is not shown here, and possible intermediate layers, as described below.

The top layer can consist entirely of multicomponent fibers according to the present invention, the top layer can also be a traditional top layer made from a wide range of materials, such as woven and non-woven materials (for example, non-woven canvas from fibers). Suitable woven and non-woven materials may consist of natural fibers (e.g., wool or cotton fibers), synthetic fibers (e.g., polymer fibers such as polyester, polyamide, polypropylene or polyethylene fibers), or from a combination of natural and synthetic fibers with multicomponent fibers according to the present inventions mixed with the above fibers. When the top layer contains non-woven canvas, the canvas can be made by a wide range of known technologies. For example, the canvas may be melt-spun, obtained by carding machines, obtained by the wet method, obtained by the aerodynamic method, hydro-bound, obtained by combinations of the above methods or the like.

The top layer may contain at least 50 wt.%, Preferably at least 65 wt.% And most preferably at least 70 wt.% Of multicomponent fibers. With a low ratio of multicomponent fibers, these fibers can be concentrated on the side of the upper layer facing the owner in order to enhance the thermoregulatory effect of these fibers.

Figure 5 shows a cross section of the absorbent article of Figure 4. The bottom layer 501 may consist of an elastic film, for example, a polymer film. Examples of polymeric materials in a film are polyethylene (PE), polypropylene (PP), polyester or some other suitable materials such as a hydrophobic non-woven layer or a laminate of a thin film and non-woven material. These types of material are often used in order to obtain a soft and fabric-like surface on the lower layer 501. The lower layer 501 can be “breathable” so that it allows steam to pass through, although also preventing liquid from entering. Breathable materials can consist of porous polymer films, non-woven laminates obtained from melt-spun layers or aerodynamically, and laminates obtained from porous polymer films and non-woven materials.

The lower layer may have an adhesive attachment in the form of glue rollers, for example, on the side of the lower layer, which is facing away from the upper layer, to secure them in panties, trousers or sweatpants. Release material may be applied over the adhesive in order to protect the adhesive when the product is not in use.

The absorbent article may also comprise an absorbent core 502 or a structure between the upper layer 503 and the lower layer 501. The absorbent core 502 may consist of one or more layers of cellulosic fibers, for example, cellulosic fluff pulp, airborne, dry defibrillated or compressed pulp. Other materials that may be used include, for example, absorbent non-woven material, foam, synthetic fiber or peat. In addition to cellulosic fibers or other absorbent materials, the absorbent core may also contain superabsorbent materials, so-called SAPs (superabsorbent polymers), which are materials in the form of fibers, particles, granules, films or the like. Super absorbent polymers are inorganic or organic materials that are capable of swelling in water and are insoluble in water, which show the ability to absorb at least 20 times their own weight in an aqueous solution containing 0.9 wt.% Sodium chloride. Organic materials that are suitable for use as a super absorbent material may include natural materials such as polysaccharides, polypeptides and the like, as well as synthetic materials such as synthetic hydrogel polymers. Such hydrogel polymers may include, for example, alkali metal salts of polyacrylic acids, polyacrylamides, polyvinyl alcohol, polyacrylates, polyacrylamides, polyvinylpyridines and the like. Other suitable polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, copolymers of isobutylene and maleic anhydride, and mixtures thereof. Hydrogel polymers are preferably readily crosslinkable to ensure that the material remains substantially insoluble in water. Preferred superabsorbent materials are also surface crosslinkable, such that the outer surface of the shell of the superabsorbent particles, fibers, spheres, etc. has a higher crosslink density than the inside of the super absorbent material. The proportion of superabsorbent materials in the absorbent core may be 10-90 wt.% Or preferably 30-70 wt.%.

The absorbent core may contain layers of various materials with different characteristics in terms of their ability to receive liquid, ability to distribute liquid, and storage capabilities. The absorbent core more often does not go in the longitudinal direction and can be, for example, rectangular, T-shaped or in the form of an hourglass. The hourglass-shaped core is wider in the front and back parts than in the connecting part to ensure efficient absorption, while at the same time, the design facilitates the molding of the product close to or around the wearer, resulting in a better fit around the legs.

The absorbent article may also include a transfer layer between the top layer and the absorbent core. The transfer layer is a porous elastic material and may contain one or more of the following: curling, packing, fiber web obtained on a carding machine, super absorbent particles or super absorbent fibers. The transfer layer has a high ability to instantly receive liquid and is capable of temporarily storing the liquid before it is absorbed by the adjacent absorbent core. The transfer layer may cover all or parts of the absorbent core.

The upper layer, the lower layer and any intermediate layers are sealed at the edges of the product, which can be accomplished, for example, by heat welding or in some other traditional way.

The absorbent article may also contain “wings” on its sides. It may also contain elastic in order to provide better contact with the body when the product is worn, as well as reduce leakage.

Components of an absorbent article, which may predominantly contain or entirely consist of multicomponent fibers according to the present invention, are side plates, tapes and other components that are in contact with the wearer's skin during use of the absorbent article.

A textile material containing multicomponent fibers according to the above is also contemplated according to the present invention. Textile material is preferably used in clothing. Thermostatic multicomponent fibers are especially interesting for use in sportswear, workwear and underwear. In this type of application, the multicomponent fibers of the invention can also be blended with other types of fibers, such as synthetic fibers, cotton, wool and rayon. This may be advantageous in terms of good moisture transfer and / or absorption of the latter type of fiber, contributing to the comfort of the sock. Clothing also includes patient care products, such as sheets, bathrobes, face masks and hats, spacers in jackets, etc.

All characteristics related to multicomponent fibers can also be applied to fibers in a fabric, in an absorbent article, and in a textile material.

When phase transformation material is used in multicomponent fibers, the strength of the fibers may be lower compared to fibers not containing phase transformation material. To improve the strength of, for example, a non-woven material containing multicomponent fibers according to the present invention, fibers having high strength can be mixed with multicomponent fibers according to the present invention to obtain a non-woven material.

The same applies when multicomponent fibers are used in textile material. In the preparation of yarns for textile material, part of the filaments used to make yarns can be filaments that are more durable than filaments containing phase transformation material.

In addition, the present invention relates to a method for producing a multicomponent fiber 605 (see figure 6, which shows a section of a nozzle plate assembly 601), comprising at least two elongated fiber bodies 606, 607, where the first fiber body 606 consists of a first material 602, and the second fiber body 607 consists of a second material 603 and surrounds the first fiber body 606, where the method comprises:

a) obtaining a first material 602 by mixing the phase transformation material with at least a molten viscosity modifier,

b) cooling the mixture to a hardened mixture,

c) processing the hardened mixture into a dispersed form,

d) providing second material 603,

e) introducing a first material 602 and a second material 603 into a fiber extrusion die assembly and

f) extruding the first material 602 and the second material 603 so as to form a multicomponent fiber 605, in which the second material 603 surrounds the first material 602.

In the figure, all stages are not shown.

All materials described above can be used to produce multicomponent fibers according to the present invention.

The present invention will now be described with the help of the following examples.

experimental part

Methods

Density is determined according to ISO 1183-2.

Melt Flow Rate (MFR)

The ability of polymer melts to flow through a capillary mouthpiece under load is determined according to ISO 1133. MFR provides information on both molecular weight and processability of polymers. The melt flow rate (MFR) is defined as the mass of polymer in grams flowing for 10 minutes through a capillary of a certain diameter and length under applied pressure using specified alternative gravimetric loads for alternative specified temperatures. The measurements in this work were performed at 190ºC using a load of 21.6 kg and using a capillary with a diameter of 2.095 mm and a length of 8.0 mm.

Rheological tests

Rheological tests are carried out using a Bohlin rheometer with a controlled voltage of the type “cone-and-plate” (CS Melt) in the variant of oscillation (the amplitude of the sinusoidal shear strain was 1%). The diameter of the plate is 25 mm and the cone angle is 5.4 °. During heating and testing, the sample chamber is purged with nitrogen. In this way, curves showing the value of the complex viscosity (in units of Pascal · second (Pa · s)) with respect to the angular frequency in units of radians per second (rad / s) are recorded.

DSC analysis

Thermal properties are examined using a Perkin Elmer DSC 7 differential scanning calorimeter. In the first scan, the sample is heated from 0ºC to 50ºC at a rate of 10ºC / min. After annealing at this temperature for 1 min, the sample is cooled to 0ºC at a rate of 5ºC / min. The heating rate in the second scan is 10ºC / min. Unless otherwise stated, peak melting points and heat of fusion (calculated by the area under the peak of melting and the mass of the sample) refer to the second scan from 0 to 50ºC. The heat of fusion in units of Joule per gram (J / g) is calculated by dividing the melting energy (the area under the melting peak) by the mass of the sample.

Tear resistance and titer

The fiber properties (titer, tensile strength and elastic modulus) are determined using a Vibrodyn (Lenzing) tensile testing apparatus. The sample length is 20 mm and the test speed is 20 mm / min. Before testing, the samples are conditioned at 20ºC and 65% relative humidity for at least 24 hours. For this material composition, the titer is an indirect measure of the filament diameter and is expressed in units of g / 1000 or 10000 m of filament (tex or dtex, respectively). Tear resistance is a measure of the strength of the filament (the maximum force held by the filament during the tensile test divided by the titer of the filament) and is expressed in units of cN / tex. The modulus of elasticity is a measure of the stiffness of the filament and is calculated as the force at 1% strain divided by the titer of the filament and is expressed in units of cN / tex. Elongation is a measure of strain at break.

Preparation of polymer-wax mixtures

The polymer granules / powder is melted with wax in a heated oven with slow stirring. The oven is heated to approximately 180ºC. During heating, the polymer particles gradually melt and the wax begins to migrate into particles, which gradually swell in size. After some time (5-30 minutes, depending on the type of polymer, the size of the polymer particles and the size of the load), the swollen polymer particles coalesce into a viscous melt. Then the polymer-wax mixture is cooled to room temperature. To further ensure a homogeneous mixture of wax and polymer, the solid mixture is loaded into a heated Brabender mixer (180 ° C) and the melt is homogenized for 5 minutes at a speed of 50 rpm. After the melt is homogenized in a Brabender mixer, the material is allowed to cool, where then the material is crushed into granules with a size of approximately 2-4 mm. The first material can be obtained and can be stored until a multicomponent fiber is obtained. Thus, all stages should not be carried out directly one after another.

Bicomponent Fiber Spinning

The melt spinning of the fibers is carried out using an ESL laboratory spinning machine, see figure 7. The die 705 is designed to melt the bicomponent fibers of the sheath / core, see figure 6. The materials for the sheath and core are melted separately using two 25 mm extruders 701 and 703 , which, in turn, are supplied with power by two gear pumps 702 and 704, figure 7. Two gear pumps 702 and 704 supply power to the die 705. The speed of the extruders is automatically controlled by a feedback control system with a channel providing constant pressure at the inlet of the gear pump 702 and 704. A cross section of the die plate assembly is shown in Figure 6. The first material 602 and the second material 603 are loaded into the die plate assembly forming a bicomponent fiber 605 having a core 606 and sheath 607. Also shown is a transverse a cross-section of a bicomponent fiber 605 showing a core 606 and a sheath 607.

The following is a more detailed description of the spinning mill in FIG. 7. The various elements in FIG. 7 are:

701. An extruder for a first material containing phase transformation material

702. Gear pump for a first material containing a phase transformation material

703. The extruder for the second material

704. Gear pump for the second material

705. Extrusion head (die)

706. Pick-up roll

707. Pairs of exhaust rollers

708. Pairs of exhaust rollers

709. Pairs of exhaust rollers

710. Winding device

The volumetric flow rate of the material of the shell and the core is set by the corresponding speeds of gear pumps. Mass flow rate can be calculated from the volumetric flow rate and material density at the processing temperature. In all experiments, the total (sheath + core material) volumetric flow rate is kept constant at 24 cm ³ / min. By controlling the speeds of gear pumps for shell and core materials, various shell / core filament ratios can be achieved.

After exiting the die 705, the filaments 711 are first stretched (reduced diameter) in the molten state (melt drawn) during simultaneous cooling. The degree of drawing at the stage of drawing the melt between the hole of the die 712 and the pick-up roller 706 is determined by the ratio V1 / V0, where V0 is the average melt velocity in the holes of the die 604 (Figure 6) (total volumetric flow divided by the total area of the holes) and V1 is the linear speed of the take-off roller 706. In the second stage, the solidified filaments are additionally stretched between several pairs of tuned exhaust rollers 707, 708, 709 on the melt drawing line. The degree of drawing (DR) in the solid drawing method is aetsya ratio DR = V2 / V1, where V1 represents the linear speed of the roller 706 and the selecting V2 represents the linear speed of the last pair of exhaust rollers 709. In a manner drawing in the solid state dramatically increases fiber strength. In practice, there are many possible variations in the method of spinning the melt, schematically shown in figure 7. For example, drawing in the solid state can be carried out in a separate stage. For some materials (for example, PET), the stage of drawing in the solid state may be omitted if the degree of drawing V1 / V0 is sufficiently high, corresponding to sampling speeds in the range of 5000-7000 m / min. In this case, a satisfactory strength is developed through the voltage introduced by crystallization already in the process of drawing the melt.

Phase Transformation Materials

Examples of some hydrocarbon waxes that can be used as MFPs are presented in Table 1.

Table 1
Properties of the phase transformation of some well-known linear chain hydrocarbons Phase Transformation Material The number of carbon atoms (n) Melting point (ºC) Heat of Fusion (J / g) n-octadecane eighteen 28,2 242 n-nonadecane 19 32.1 187 n-eicosan twenty 36.6 246 n-geneukosan 21 40,2 200

Table 2 shows the melting temperature and heat of fusion of some commercial MFPs supplied by Rubitherm Technologies GmbH, Berlin, Germany. It should be noted that the results of the Applicant's own measurements are presented.

table 2
Melting point and heat of fusion of some commercial hydrocarbon MFPs Grade Melting point [ºC] Heat of Fusion [J / g] R27 28 150 R31 thirty 146 R35 34 150

Examples

Example 1

Different amounts of viscosity modifier in the form of polyethylene materials (high density polyethylene) are mixed with RT 27 (hydrocarbon wax manufactured and supplied by Rubiterm GmbH in Germany, see table 2). The melt flow rate of polyethylene materials is determined by the method described in the "Melt flow rate" section. The mixing of the viscosity modifier and polyethylene is then carried out according to the method described in the section "Obtaining polymer-wax mixtures". Then the viscosity of the various mixtures is investigated in accordance with the methodology of the section "Rheological tests". The angular frequency of 10 rad / s, used for comparison, is selected with approximate correspondence with the wall shear rate in a cylindrical pipe with a diameter of 2.5 mm, as shown in figure 6.

The results are presented in figure 8 in the form of a graph showing the value of the complex viscosity at 190ºC and 10 rad / s with respect to wt.% RT 27. It is shown that the lower the melt flow rate of the polyethylene, the smaller the amount of polyethylene needed to obtain high viscosity. Thus, the low melt flow rate of the viscosity modifier will increase the viscosity of the first material. For a given polymer, the lower the MFR of the polymer viscosity modifier, the smaller the amount of viscosity modifier needed to achieve a given viscosity.

The shaded area in Figure 8 gives an indication of the shear viscosities of typical polymer grades (e.g., polypropylene, polyamide, polyester) intended for melt spinning at their respective processing temperatures. Again, an angular frequency of 10 rad / s is taken for comparison.

In this particular example (hydrocarbon wax mixed with polyethylene as a viscosity modifier), in order for the first material containing MFP to reach a viscosity in the range of the second material, with which it must be coextruded to produce multicomponent fibers of the invention, it is seen that approximately 50 wt.% Polyethylene with MFR = 120 to bring the viscosity to an acceptable level (darkened area in figure 8). If the MFR is reduced to 8, only 25-30 wt.% Is required. When choosing ultra-high molecular weight polyethylene (UVMPE) having an MFR <0.1, only 10-15 wt.% Is required as a viscosity modifier.

However, it was experimentally found that the extrusion of a mixture of RT 27 with 10-15 wt.% UHMWPE through a capillary with a shear rate of 10 s ^-1 gives a strong destruction of the melt, a phenomenon well known to specialists in the field of polymer extrusion. This is confirmed by spinning a bicomponent fiber (core / sheath configuration) using the first material containing MFP (RT 27 mixed with 10-15 wt.% UVMPE) and spinning a melt of grade PP (HG 245 FB obtained by Borealis) as the second material . The molten filaments emerging from the openings of the die are twisted strongly, and spinning of the fiber is not possible. This type of melt fracture is sometimes called “elastic turbulence” and is probably caused by the very high elasticity imparted by the very long molecular chains of the UHMWPE polymer. Thus, the limit of the MFR of the polymer, which can be used as a viscosity modifier, is reduced.

Example 2

The MFP efficiency of a polymer containing MFP, in terms of its amount of latent heat (heat of fusion / crystallization), is considered in Table 3. The polymer containing MFP corresponds to the first material in a multicomponent fiber. RT 31 hydrocarbon wax is mixed with various polyolefins, which is carried out in accordance with the procedure described in the section "Obtaining polymer-wax mixtures", and the heat of fusion in the range of 0-50ºC is measured using DSC in accordance with DSC analysis, as discussed above.

Table 3 Material % Wax, wax (RT 31) ^d Heat of fusion, J / g MFP efficiency,% FS1560 (HDPE) ^a 65 93.7 99,4 MFR ^e = 9 ^e 70 100.5 99.0 Density = 956 kg / m ³ 75 108.7 100.0 80 120,4 103.8 BL0521 (HDPE) ^a 65 88.7 94.1 MFR ^e = 2.5 ^e 70 94.8 93,4 Density = 952 kg / m ³ 75 102.3 94.1 80 112.8 97.3 FL1500 (HDPE) ^a 65 - - MFR ^e = 8 ^e 70 - - Density = 950 kg / m ³ 75 - - 80 105.5 91.0 EZP2207 (LLDPE / Butylene) ^b 65 - - MFR ^e > 65 ^eh
MFR ^f = 0.7 ^f 70 85.7 84,4 Density = 922 kg / m ³ 75 - - 80 102.9 88.7 Elvaloy 3117 AC (ethylene butyl acrylate copolymer, EBA) ^with 65 - - MFR ^e > 80 ^eh
MFR ^f = 1.5 ^f 70 85.9 84.6 Density = 924 kg / m ³ 75 - - 80 98.2 84.6 HE445FB (PP) ^a 65 - - MFR ^e > 80 ^eh
MFR ⁹ = 11 ⁹ 70 84.2 82.9 Density = 903-910 kg / m ³ 75 - - 80 99.9 86.1 RT31 ^d one hundred 145 one hundred ^a Supplier - Borealis
^b Supplier - Equate
^d Supplier - Rubitherm
^e g / 10 min, as determined at 190 ° C with a load of 21.6 kg according to ISO 1133
^f g / 10 min, as determined at 190ºC with a load of 2.16 kg according to ISO 1133
^g g / 10 min, as determined at 230ºC with a load of 2.16 kg according to ISO 1133
^h not determined by Applicant, estimated level
- experiment not completed

High MFP efficiencies were obtained. In the case of the polyethylene family, material FS1560 with the highest density shows the highest efficiency relative to the heat of fusion. As can be noted, one sample (20% FS1560) exceeds 100% MFP efficiency.

Example 3

In the following examples, the core material corresponds to the first material, and the sheath material corresponds to the second material according to the present invention.

In this example, a group of bicomponent fibers with a sheath / core structure is prepared as described above in the “Melt Spinning of Bicomponent Fibers” section. The core material is a mixture of 70 wt.% RT27 and 30 wt.% HDPE (FL1500, supplier - Borealis). The shell is PP (HG 245 FB, supplier - Borealis). The parameters of the spinning from the melt are presented in table 4.

Table 4 Gear pump speed, rpm
(core) 3-6 Gear pump speed, rpm
(shell) 7-4 The total flow rate, cm ³ / min 24 Screening roll, m / min 250 Lower roller, m / min / Temperature, ºC 275/80 Average roller, m / min / Temperature, ºC 625/90 Top roller, m / min 750 Extraction degree (V2 / V1) 3.0 Extruder temperatures, ºC
(core / sheath) 170, 180, 190 / 190,200,210 Gear pump temperatures, ºC
(core / sheath) 210/210 The temperature of the die, ºC 210

Some fiber properties are presented in table 5.

Table 5 Core / Ratio
shell (in relation to mass) wt.% MFP Heat of Fusion [J / g] Thermal Efficiency [%] Caption [dtex] Elastic modulus [cN / tex] Tear Resistance [cN / tex] Elongation [%] 0/100 * 0 - - 11.0 270 29th 196 30/70 21 11.6 37 10.5 141 16 126 40/60 28 16,2 39 10,2 130 eleven 73 50/50 35 33.3 63 10.7 126 8.4 47 60/40 42 43.8 70 9.5 142 7.6 34 * One component fiber

Properties are determined using the methods discussed above at the beginning of the experimental part.

The thermal efficiency of multicomponent fibers is expressed as the ratio ΔH _{fiber /} (w _MFP · ΔH _MFP ) · 100. As can be seen from table 5, thermal efficiency increases from 37 to 70% with an increase in the shell / core ratio from 30/70 to 60/40, which corresponds to an increase in the MFP content from 21 to 42 wt.% With respect to the total fiber mass. Thermal efficiency below 60% is considered low, which means that a significant part of the introduced MFP does not participate in the melting process.

The low efficiency is probably due to the migration of hydrocarbon wax from the core to the shell, where it dissolves in the amorphous parts of polypropylene. This is also due to the fact that polypropylene dissolves in hydrocarbon wax. If this occurs, the thermal efficiency will be partially lost, since the MFP, dissolved in the amorphous parts of the polyolefin, has a low tendency to crystallization. For applications of multicomponent fibers of the invention in objects that need to be washed regularly (for example, clothes and home textiles), it can be assumed that the continuous migration of MFPs from fibers will greatly degrade their thermal efficiency over time and with washing cycles. For disposable products (such as wipes), MFP migration may not be a problem.

Example 4

In the following example, a group of bicomponent fibers with a sheath / core structure is prepared as described above in the “Melt Spinning of Bicomponent Fibers” section. The core material is a mixture of 35% RT31, 35% RT35 and 30 wt.% HDPE (FL1500, supplier - Borealis). The casing is PET (GL-BA 6105 with a characteristic viscosity of 0.61, measured according to ASTM D4603, supplier - TWD Polymere, Germany). The parameters of the spinning from the melt are presented in table 6.

Table 6 Gear pump speed, rpm (core) 4-6 Gear pump speed, rpm (shell) 6-4 The total flow rate, cm ³ / min 24 Screening roll, m / min 250 Lower roller, m / min / Temperature, ° C 275/80 Middle roller, m / min / Temperature, ° C 625/80 Top roller, m / min 750 Extraction degree (V2 / V1) 3.0 Extruder Temperature ° C
(core / sheath) 170,200, 210 / 280,300,290 Gear pump temperature, ° C
(core / sheath) 230/280 Die temperature, ° C 280

The properties of the fibers are presented in table 7.

Table 7 Core / Ratio
shell (in relation to mass) wt.% MFP Heat of Fusion [J / g] Thermal Efficiency [%] Caption [dtex] Elastic modulus [cN / tex] Tear Resistance [cN / Tex] Elongation [%] 30/70 21 23.8 78 10.3 388 21 80.5 40/60 28 31.8 78 14.8 244 15.9 138.4 50/50 35 45.9 90 12.8 226 13.6 165.2

The thermal efficiency of fibers with polyethylene terephthalate (PET) in the shell (78-90%) is significantly higher than for fibers with PP in the shell (37-70%), see example 3 above. This can be explained by the fact that non-polar hydrocarbon waxes do not dissolve in more polar PET and vice versa. For applications of multicomponent fibers of the invention in which it is important to prevent the loss of MFP through the sheath by migration / diffusion, it is preferable that the second material forming the elongated fiber body surrounding the fiber body containing the phase transformation material is a fiber-forming polymer that does not dissolve in the phase material transformations at temperatures above the melting temperature of the fiber-forming polymer (or softening temperature in the case of an amorphous polymer). The fiber strength is very good for bicomponent fibers containing phase transformation material in quantities according to the above.

Example 5

In the following example, a group of bicomponent fibers with a sheath / core structure is prepared as described above in the “Melt Spinning of Bicomponent Fibers” section. The core material is a mixture of 35% RT31, 35% RT35 and 30 wt.% HDPE (FL1500, supplier - Borealis). The casing is PET (GL-BA 6105 with a characteristic viscosity of 0.61, measured according to ASTM D4603, supplier - TWD Polymere, Germany). The parameters of the spinning from the melt are presented in table 8.

Table 8 Gear pump speed, rpm (core) 5 Gear pump speed, rpm (shell) 5 The total flow rate, cm ³ / min 24 Screening roll, m / min 150, 300 Lower roller, m / min / Temperature, ºC 175,325 / 80 Average roller, m / min / Temperature, ºC 600, 1200/80 Top roller, m / min 750,1500 Extraction degree (V2 / V1) 5 Extruder temperatures, ºC (core / sheath) 170,200,210 / 280,300,290 Gear pump temperature, ºC (core / shell) 230/280 The temperature of the die, ºC 280

The properties of the fibers are presented in table 9.

Table 9 The ratio of core / shell (relative to weight) wt.% MFP Heat of Fusion [J / g] Thermal Efficiency [%] Caption [dtex] Elastic modulus [cN / tex] Resistance
tear strength [cN / tex] Extension
ratio [%] 40/60 28 33,2 82 11.7 578 26.8 38.7 40/60 28 32,4 80 7.1 570 26.2 28,2

The strength of the multicomponent fibers of the invention can be further increased by increasing the degree of drawing during melt spinning, as shown in the example where two groups of fibers are obtained with DR = 5 and a different titer. The materials are the same as in example 4, in which DR = 3, and the tensile strength is higher in example 5 for a core / shell ratio of 40/60 compared to example 4 with the same core / shell ratio of 40/60. Fibers with preserved thermal properties are obtained with significantly higher stiffness (modulus of elasticity) and strength (tensile strength) when the degree of drawing increases.

Example 6

In this example, polyamide is used as the second material. A group of bicomponent fibers with a sheath / core structure is prepared as described above in the “Melt Spinning of Bicomponent Fibers” section. The core material is a mixture of 75 wt.% Pure n-eicosan (supplier - Roper Thermals, USA) and 25 wt.% HDPE (FS 1560, supplier - Borealis). The sheath material is a fiber spinning grade PA-6 (Ultramid BS 703), the supplier is BASF, Germany. The measured heat of fusion of pure n-eicosan is 240 J / g. The parameters of the spinning from the melt are presented in table 10.

Table 10 Gear pump speed, rpm (core) 4-5 Gear pump speed, rpm (shell) 6-5 The total flow rate, cm ³ / min 24 Screening roll, m / min 250 Lower roller, m / min / Temperature, ° C 275/60 Middle roller, m / min / Temperature, ° C 625/65 Top roller, m / min 750 Extraction degree (V2 / V1) 3.0 Extruder temperatures, ° C (core / casing) 140, 170, 190 / 240,270,280 Gear pump temperature, ° C (core / shell) 240/270 Die temperature, ° C 270

The properties of the fibers are presented in table 11.

Table 11 Core / Ratio
shell (in relation to mass) wt.% MFP Heat of Fusion [J / g] Thermal Efficiency [%] Caption [dtex] Elastic modulus [cN / tex] Tear Resistance [cN / tex] Extension
ratio [%] 34/66 25.5 48 79 13 160 33 37 43/57 33 65 82 11.8 165 27 44

In this example, thermal efficiency is also high. This is probably due to the fact that the more polar PA-6 is insoluble in non-polar hydrocarbon waxes. For clarity, non-polar hydrocarbon waxes are also insoluble in the more polar PA-6. The strength of the fibers is good even at the degree of drawing 3. When using MFP with high heat of fusion (240 J / g in this example), HDPE with high density (956) and low MFR (9) (with high MFP efficiency and low concentration HDPE (even with the facilitation of good processability)) as a polymer viscosity modifier and sheath material with low solubility of hydrocarbon wax MFP strong multicomponent fibers (27-33 cN / tex) with high heat of fusion (48-65 J / g) can be obtained already with average content AANII MFP 25-33 wt.% relative to the total weight of fibers.

For all multicomponent fibers, with the exception of those where the second material is polypropylene, the thermal efficiency of multicomponent fibers is more than 70%. This may depend on the fact that polypropylene can be dissolved in the phase transformation material. Then the phase transformation material is not used equally. It can also lead to some leakage of the phase transformation material. This can be a problem for fabrics used, for example, in clothes that are washed and used for a long time. However, when fibers are used in disposable products, this is not an inevitable problem.

The examples show that the multicomponent fibers according to the present invention have good latent heat, good MFP efficiency, good thermal efficiency, high strength and are easy to obtain.

Claims (24)

1. A multicomponent fiber (10, 20, 30, 40, 50, 60), containing at least two elongated fiber bodies (11, 21, 31, 41, 51, 61; 12, 22, 32, 42, 52 , 62), in which the first fiber body (11, 21, 31, 41, 51, 61) consists of the first material containing the phase transformation material, and the second fiber body (12, 22, 32, 42, 52, 62) consists of the second material and surrounds the first fiber body (11, 21, 31, 41, 51, 61), characterized in that the phase transformation material is in its original form, the first material containing a viscosity modifier selected from polyolefins having a density in the range e 890-970 kg / m ³ as determined at room temperature according to ISO 1183-2, and a melt flow rate in the range of 0.1-60 g / 10 min as determined at 190 ° C under a load of 21.6 kg according to ISO 1133. 2. The multicomponent fiber according to claim 1, characterized in that the viscosity modifier has a density above 920 kg / m ³ , preferably above 950 kg / m ³ , as determined at room temperature according to ISO 1183-2. 3. The multicomponent fiber according to claim 1 or 2, characterized in that the viscosity modifier has a melt flow rate in the range of 0.1-50 g / 10 min, preferably 0.1-20 g / 10 min, more preferably 0.1- 10 g / 10 min, as determined at 190 ° C under a load of 21.6 kg according to ISO 1133. 4. The multicomponent fiber according to claim 1, characterized in that the phase transformation material has a latent heat of at least 100 J / g and, preferably, at least 140 J / g 5. The multicomponent fiber according to claim 1, characterized in that the multicomponent fiber contains the first material having an MFP efficiency, as defined by the ratio ΔH _mixture / (w _MFP · ΔH _MFP ) · 100, at least 90%, and more preferably at least 95, where the ΔH _mixture is the heat of fusion of the first material containing the MFP, and w the _MFP is the mass fraction of the MFP in the first material containing the MFP, and the ΔH _MFP is the heat of fusion of pure MFP. 6. The multicomponent fiber according to claim 1, characterized in that the multicomponent fiber has thermal efficiency, as defined by the ratio ΔH _fiber / (w _MFP · ΔH _MFP ) · 100, at least 60, expressed in%, preferably at least , 70%, more preferably at least 75%, where ΔH _fiber is the measured heat of fusion of a multicomponent fiber containing MFP, and w _MFP is the mass fraction of MFP, and ΔH _MFP is the measured heat of fusion of pure MFP. 7. The multicomponent fiber according to claim 1, characterized in that the viscosity modifier is present in an amount of less than 50 wt.%, Preferably less than 40 wt.%, And more preferably less than 30 wt.%, Calculated with respect to the total weight of the first fiber body . 8. The multicomponent fiber according to claim 1, characterized in that the MFP is present in an amount of more than 50 wt.%, Preferably more than 60 wt.%, And, more preferably more than 70 wt.%, Calculated with respect to the total weight of the first fiber body. 9. The multicomponent fiber according to claim 1, characterized in that the first material contains a phase transformation material and a viscosity modifier in an amount of at least 90 wt.% Together, calculated with respect to the total weight of the first material. 10. The multicomponent fiber according to claim 1, characterized in that the phase transformation material is selected from hydrocarbon waxes with a melting point in the range of 20-50 ° C, preferably in the range of 25-45 ° C, and more preferably in the range of 27-40 ° FROM. 11. The multicomponent fiber according to claim 1, characterized in that the phase transformation material is selected from linear hydrocarbon waxes. 12. The multicomponent fiber according to claim 1, characterized in that the viscosity modifier is polyethylene. 13. The multicomponent fiber according to claim 11, characterized in that the viscosity modifier is polyethylene with a density above 950 kg / m ³ . 14. The multicomponent fiber according to claim 1, characterized in that the fiber has a latent heat of at least 20 J / g, preferably at least 30 J / g, and most preferably at least 40 J / g, as determined by the DSC method in the range of 0-50 ° C. 15. The multicomponent fiber according to claim 1, characterized in that the fiber has a strength above 10 cN / tex, preferably above 15 cN / tex, and most preferably above 20 cN / tex. 16. The multicomponent fiber according to claim 1, characterized in that the ratio between the viscosity of the first material and the second material satisfies the condition 0.1 <viscosity 1 / viscosity 2 <10, where viscosity 1 is the complex viscosity at an angular frequency of 10 rad / s of the first the material containing the MFP, and viscosity 2 is the complex viscosity at an angular frequency of 10 rad / s of the second material, where the viscosity is measured at the extrusion temperature used in the process of spinning from the melt, i.e. at the set die temperature. 17. The multicomponent fiber according to claim 1, characterized in that the second material is a fiber-forming polymer that does not dissolve in the phase transformation material at temperatures above the melting temperature of the fiber-forming polymer or softening temperature in the case of an amorphous polymer. 18. The multicomponent fiber according to claim 1, characterized in that the second material contains polymers selected from polyesters and polyamides. 19. A multicomponent fiber according to claim 1, characterized in that the fiber contains at least one or more first fiber bodies (51) and at least one or more second fiber bodies (52). 20. A multicomponent fiber according to claim 1, characterized in that the fiber contains at least one or more first fiber bodies (61), at least one or more second fiber bodies (62) and at least one or more than third fiber bodies (63), which are composed of a third material. 21. A textile material containing multicomponent fibers according to any one of claims 1 to 20. 22. A fabric containing multicomponent fibers according to any one of claims 1 to 20. 23. The fabric according to item 22, wherein the fabric has a latent heat of at least 10 J / g, preferably at least 20 J / g 24. An absorbent article containing multicomponent fibers according to any one of claims 1 to 20.

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