KR101167757B1 - High-strength, light non-woven of spunbonded non-woven, method for the production and use thereof - Google Patents

Abstract

The present invention relates to a high strength lightweight nonwoven fabric processed into a spunbonded nonwoven fabric, in particular for use as a reinforcing or reinforcing material, the high strength lightweight nonwoven fabric comprising one or more layers of melt-spun synthetic filaments The filament is cured by high energy water jets, whereby the high strength lightweight nonwoven contains a thermally activatable binder, the binder being provided in the form of one or more thin layers over a layer of melt-spun filaments. Moreover, this invention describes the manufacturing method of such a high strength lightweight nonwoven fabric.

Description

High-strength lightweight nonwoven fabric processed with spunbonded nonwoven fabric, manufacturing method and use thereof {HIGH-STRENGTH, LIGHT NON-WOVEN OF SPUNBONDED NON-WOVEN, METHOD FOR THE PRODUCTION AND USE THEREOF}

The present invention relates to a high-strength lightweight nonwoven fabric processed from a spunbonded non-woven fabric, wherein the high-strength lightweight nonwoven fabric is comprised of melt-spun synthetic filaments cured by high energy water jets. It includes more layers. Moreover, this invention relates to the manufacturing method and use of such a nonwoven fabric.

The present invention aims to provide a high strength lightweight nonwoven fabric processed from a spunbonded nonwoven fabric, which is characterized by high initial modulus as well as high strength. High initial modulus reduces the likelihood of an initial draft and the resulting width skipping in conventional production processing steps.

This object is achieved by a nonwoven fabricated from a spunbonded nonwoven having all the features of claim 1. The method for producing a nonwoven fabric according to the invention processed into a spunbonded nonwoven fabric is described in claim 12 and the preferred use of the invention is described in claim 16. Preferred embodiments of the invention are described in the dependent claims.

In accordance with the present invention, a high strength lightweight nonwoven fabric processed into a spunbonded nonwoven fabric comprises one or more layers of melt-spun synthetic filaments cured by high energy water jets, wherein the high strength lightweight nonwoven fabric is a thermally activatable binder. And the binder is provided in the form of one or more thin layers over the layer of melt-spun filaments.

Interlacing yarns by high energy water jets results in a number of very weak cohesive bonds across the cross section of the nonwoven. All of the above bonds, which only depend on the interfacial aggregation mode, are inherently very weak, and in any case weaker than the strength of such bonded yarns. The sufficiently high forces formed during the production processing step act on the spunbonded nonwovens cured in this manner, so that the weakly cohesive bonds produced by water jet curing are individually loaded without damaging the yarns that are made up. Is released. Only when all the threads are distributed in a sufficiently wide periphery and remain intact in the direction of the load will the sum of the weak individual bond strengths take effect and the nonwoven will have a high strength.

Initial elasticity is specified as low initial modulus in the power-expansion diagram. In practical use, there is a length draft associated with the corresponding width skip under the corresponding load. This length draft makes it difficult or often impedes the application of such a water jet method in cured spunbonded nonwovens.

As a result, the problem of raising the initial modulus becomes a priority technical problem.

Surprisingly, in addition to water jet bonds, by applying one or more thin layers processed with a binder over a layer of melt-spun synthetic filaments. It can be seen that additional bonds (or points of bonding) between the spunbonded nonwoven filaments are controlled through a combination of subsequent water jet curing, drying and activation of the binder. Thus, a unique combination occurs by a very small number but significantly stronger adhesive bonds and a very large number but weakly cohesive manner.

The large number of thin spunbonded nonwoven filaments, coupled by the additional joining points described above, help the nonwoven to have high modulus values and sufficient dimensional stability for enlargement. The nonwoven fabric according to the invention does not require additional measures for dimensional stabilization such as, for example, stress control in enlarged machining. Such an effect, in particular, leads to speculation that some of the binder may be caused by high energy water jets to penetrate deep into the nonwoven sheets to form bonding points there.

The nonwovens according to the invention may also be formed of one or multiple layers of spunbonded nonwovens and binders. Other additional sheets may also be provided as long as such additional sheets have meaning in the individual application.

Suitable binders are in particular low melting point thermoplastic polymers, in which case such thermoplastic polymers preferably have their melting temperatures sufficiently lower than the melting temperatures of spunbonded nonwoven filaments. The melting temperature is preferably at least 10 ° C., particularly preferably at least 20 ° C. lower than the melting temperature of the spunbonded nonwoven filaments, so that the spunbonded nonwoven filaments are not damaged during thermal activation.

Preferably the low melting thermoplastics also have a wide softening range. The advantage of this wide softening range is that the thermoplastic polymer used as binder can already be activated at lower temperatures than at its effective melting point. From a scientific point of view, the binder can be sufficiently flexible and then adhered to the filaments to be bonded, without necessarily having to completely blend. In this way the degree of bonding between the spunbonded nonwoven filaments and the binder in the activation step can be controlled.

Preferably, the low melting point thermoplastic polymers are substantially polyolefins, in particular polyethylene, copolymers containing large amounts of polyethylene components, polypropylene, copolymers containing large amounts of polypropylene components, copolyesters, in particular polypropylene terephthalates and / Or polybutylene terephthalate, polyamide and / or copolyamide. When selecting suitable polymers with low melting points, the requirements for future typical applications must be considered.

The weight ratio of the low melting point polymer, based on the total weight of the nonwoven fabric, is preferably at least 7%. If the ratio of the molten adhesive is very low, this will result in very low initial modulus amplification and, in some circumstances, will not be sufficient for future use.

Preferably the weight ratio is 9% to 15% by weight. If it exceeds 15% by weight, in some cases, the negative effect of a very large number of strong adhesive bonds on the tear strength may be predominant.

However, the use of molten adhesive at lower rates of less than 7% per se can be included in the present invention as it is particularly desirable for certain applications.

The low melting point polymer can be present, for example, in the form of fibers or fibrils. As the fibers, bicomponent fibers can be used in particular, in which case the low melting components are thermally activatable binders.

The present invention makes it possible to use less denier filaments for spunbonded nonwoven filaments. In this case, excellent strength and sufficient covering power are achieved even with a small weight per unit area. The fiber denier is preferably 0.7 to 6 dtex. The advantage of fibers having deniers of 1 to 4 dtex is that not only good surface covering is ensured as well as sufficient overall strength when the weight per unit area is average.

The nonwovens according to the invention preferably comprise filaments made of polyester, in particular polyethylene terephthalate, and / or polyolefins, in particular polypropylene. Such materials are particularly suitable because the materials are made of a large amount of crude raw material, which is always available in sufficient quantity and quality. Polypropylene as well as polyester is well known for its utility in fiber and nonwoven fabrics.

Matrix fiber polymers, for example polyethyleneennaphthalat (PEN) and / or copolymers in addition to polyethyleneterephthalat (PET) to meet specific needs for industrial nonwovens such as high initial modulus and / or stiffness and / or UV stability and / or alkali stability. And / or mixtures of PET and PEN may also be used. Compared to PET, PEN is characterized by a higher melting point (about + 18 ° C) and a higher glass temperature (about + 45 ° C).

Suitable methods for producing the nonwovens according to the invention include the following processing steps:

a) placing one or more layers of synthetic filaments using a spunbonded nonwoven process;

b) providing at least one thin layer of thermally activatable binder;

c) dispensing the binder using high energy high pressure water jets and curing the spunbonded nonwoven filaments;

d) drying

e) a heat treatment step for activating the binder;

The production of spunbonded nonwovens, ie the spinning of various polymers, in particular synthetic filaments of polypropylene or polyester, is the same as in the prior art, such as attaching the polymers with irregularly oriented nonwovens on a carrier. Large industrial devices with a width of 5 m or more can be purchased from many companies. The large industrial devices can use one or multiple spinning systems (spinning beams) and can be set to the desired output. Hydroentangling systems in water jet curing are also prior art. Such devices may also be widely provided by a number of manufacturers. The same is true for dryers and winders.

Thermally activatable binders may be provided using a variety of methods, for example by powder coating, in the form of a dispersion. However, the binder may be provided in the form of fibers or fibrils, preferably by a melt-blown method or an airlaying method. The methods are also well known and variously described in the literature.

An advantage of the melt-blown method or the dispersion integration method is that it can be arbitrarily combined with spinning systems for spunbonded nonwoven filaments.

As is known from DE 198 21 848 C2, the water jet cure draws 5% of the initial modulus measured longitudinally as a stress and reaches a longitudinal intrinsic strength of preferably 4.3 N / 5 cm per gram of area. And at least 0.45 N / 5 cm per g area unit g / m 2. Thus, sufficient strength of the spunbonded nonwoven fabric is ensured and the distribution of the binder inside the spunbonded nonwoven layer is sufficiently well ensured.

In the sense of the present invention, activation means generating the binding points using a binder, for example, generating the binding point by melting or melting of a low melting point polymer used as the binder. In addition to drying, heat treatment for activation is also carried out at a temperature so low that damage of the spunbonded nonwoven filaments is reliably prevented, for example, through melting or melting. For economical reasons the drying and thermal activation step of the binder is preferably carried out in one running step.

Various types of dryers may be used, such as tenters, conveyor driers or surface dryers, for drying and activating low melting polymers, but drum dryers are preferred. The drying temperature can be adjusted to the melting temperature of the polymers with a low melting point in the last step and can be optimized accordingly. In this case in particular the total melt ratio of the binder can be taken into account. In the case of such binders with a significantly broader softening range, no physical manipulation of the melting point is necessary. Rather, within the softening range, the optimization of the binding effect is already satisfied. Thereby, undesirable local problems such as adhesion of the binding components to the parts of the machine and over curing can be avoided.

The nonwovens according to the invention are particularly suitable as coating carriers, reinforcing materials or reinforcing materials because of their very good strength and high initial modulus for industrial applications.

The invention is described in detail below with reference to embodiments.

≪ Example 1 >

The test apparatus for making spunbonded nonwovens had a 1200 mm width. The test apparatus consists of a spinning nozzle that spans the entire width of the apparatus, two blow walls arranged parallel to the opposite side of the spinning nozzle, and subsequent outlet slots, the outlet slots having a diffuser ( diffuser) to form a nonwoven forming chamber. The spun filaments formed a uniform planar structure, ie a spunbonded nonwoven, on the collecting band suction filtered from the bottom in the nonwoven forming region. The spunbonded nonwoven was rolled up by compression between two rollers.

The precured spunbonded nonwovens were unrolled in a test apparatus for water jet curing. A thin sheet of short bond fibers was applied to the surface of the system using a system for dispersion integration, and then the two sheet planar structure was treated by a number of high energy water jets, thereby resulting in hydroentangle and Curing was done. At the same time the binder was dispensed into the planar structure. The cured bonded nonwoven was then dried in a drum dryer, in which case the temperature in the last section of the dryer was set such that the bond fibers were activated to cause further bonding.

In this test, spunbonded nonwovens were made of polypropylene. A spinning nozzle with 5479 spinning holes was applied over the aforementioned width. As a raw material, polypropylene granulate from Exxon Mobile (Achieve PP3155) having 36 MFIs was used. The spinning temperature was 272 ° C. The outlet slot was 25 mm wide. The filament denier was 2.1 dtex measured according to the diameter in the spunbonded nonwoven. The production speed is set at 46 m / min. The spunbonded nonwoven obtained has a weight per unit area of 70 g / m 2. In the apparatus for water curing, a sheet of very short bicomponent fibers of 16 g / m 2 in air flow is first applied to the core / shell-construction by means of a nonwoven fabric forming apparatus, in which the core is made of polypropylene, The shell is made of polyethylene. The weight ratio of the components is 50/50%. The spunbonded nonwovens were then water jet cured. Curing was carried out by six beams, which were acted alternately from both sides. The water pressures used were as follows.

Beam number One 2 3 4 5 6 Hydraulic pressure (bar) 20 50 50 50 150 150

In the case of water jet curing, by inserting the short fibers generally into the nonwoven, the short fibers did not form a transparent surface sheet.

The spunbonded nonwoven fabric processed by water jets was then dried in a drum dryer. In this case, by setting the ambient temperature of the last zone to 123 ° C., the polyethylene readily melted to form thermal bonds. Such cured nonwovens had the following mechanical values at mass per unit area of 86 g / m 2:

Tensile force
[N / 5cm] Super elongation
[%] 5% stretching force
[N / 5cm] Force at 10% elongation
[N / 5cm] Vertical 512 85 56 93 horizontal 86 105 6.0 11.9

 The intrinsic strength in the longitudinal direction was 5.95 N / 5 cm per g / m 2 and the secant modulus was 0.65 N / 5 cm per g / m 2 at 5% elongation.

<Example 2>

Polyester granulate was used in the same test apparatus as described in Example 1. The polyester granulate had an intrinsic viscosity of IV = 0.67. Spinning was carried out at a temperature of 285 ° C. by completely drying so that the residual content of water was below 0.01%. Again, a spinning nozzle having 5479 holes over a width of 1200 mm was used as in Example 1. Polymer throughput was 320 kg / h. The filaments had 2 dtex denier and very little shrinkage optically detected in spunbonded nonwovens. By setting the speed of the device to 61 m / min, the precured spunbonded nonwoven had a weight per unit area of 72 g / m 2.

The precured nonwoven was provided in the same apparatus for water jet curing. A sheet of 16 g / m 2 of bicomponent short fibers (PP / PE 50/50) was placed on the surface of the precured spunbonded nonwoven fabric. A compound fabric was then introduced into the water jet curing process using six beams set as follows.

Beam number One 2 3 4 5 6 Hydraulic pressure (bar) 20 50 80 80 200 200

In the case of water jet curing, the short bond fibers were mostly embedded inside the spunbonded nonwoven fabric, so that the short bond fibers did not form a transparent surface sheet.

The spunbonded nonwoven fabric treated by water jet was then dried in a drum dryer. In this case, by setting the ambient temperature at 123 ° C. in the last zone, the polyethylene readily fused to form thermal bonds. The nonwoven fabric thus cured had the following mechanical values at weight per unit area of 87 g / m 2.

Tensile force
[N / 5cm] Super elongation
[%] 5% stretching force
[N / 5cm] Force at 10% elongation
[N / 5cm] Vertical 530 88 59 96 horizontal 93 100 6.1 12.6

The intrinsic strength in the longitudinal direction was 6.09 N / 5 cm / g / m 2, and the inherent secant modulus was 0.68 N / 5 cm / g / m 2 at 5% elongation.

Claims (16)

A high strength lightweight nonwoven fabricated from a spunbonded nonwoven fabric comprising one or more layers of melt-spun synthetic filaments, The filaments are cured using a high energy water jet, the high strength lightweight nonwoven fabric contains a thermally activatable binder, the binder is provided in one or more thin layers in a layer of melt-spun filaments, Wherein the curing with the high energy water jet is performed after the thermally activatable binder is provided in the form of one or more thin layers in the layer of melt-spun filaments. The high strength lightweight nonwoven fabric of claim 1, wherein the binder comprises a low-melting thermoplastic polymer. The high strength lightweight nonwoven fabric of claim 2 wherein the low melting thermoplastic polymer has a melting temperature of 10 ° C. to 170 ° C. lower than the melting temperature of the synthetic filaments. 4. The high strength lightweight nonwoven fabric of claim 1 wherein the synthetic filaments have a titer of 0.7 to 6.0 dtex. The synthetic filament of claim 1, wherein the synthetic filament is polyester, polyethylenenaphthalate (PEN), copolymer of polyethylene terephthalate (PET) and PEN, a mixture of PET and PEN, polyolefin, or a combination thereof. A high strength lightweight nonwoven comprising combinations. The copolymer according to claim 2 or 3, wherein the low melting point thermoplastic polymer is actually a polyolefin, a copolymer containing a large amount of polyethylene, a polypropylene, a copolymer containing a large amount of a polypropylene component, a copolyester, a polyamide, a copoly High strength lightweight nonwovens, which are amides or polyamides and copolyamides. 4. The high strength lightweight nonwoven of claim 2 or 3, wherein the low melting thermoplastics comprise a weight ratio of 7% to 15% based on the total weight of the nonwoven. 4. The high strength lightweight nonwoven of claim 2 or 3 wherein the low melting thermoplastic polymer is provided in the form of a uniformly dispersed powder. 4. The high strength lightweight nonwoven fabric of claim 2 or 3, wherein the low melting point thermoplastic polymer is provided in the form of spun or melt-blown fibers or in the form of fibrils. 10. The high strength lightweight nonwoven fabric of claim 9 wherein the melt-blown fibers or fibrils are disposed in one uniform sheet by air. 10. The high strength lightweight nonwoven fabric of claim 9 wherein the fiber is a bicomponent fiber, wherein the low melting point components are thermally activatable binders. A method for producing a high strength lightweight nonwoven fabric according to any one of claims 1 to 3, wherein a) placing one or more layers of synthetic filaments using a spunbonded nonwoven process; b) providing at least one thin layer of thermally activatable binder; c) curing the spunbonded nonwoven filaments and dispensing the binder using high energy high pressure water jets; d) drying e) a heat treatment step for activating the binder. The method of claim 12, wherein the drying step and the thermal activation step are performed in one processing step. 13. The initial modulus of claim 12, wherein the high strength lightweight nonwoven fabric reaches a longitudinal intrinsic strength of 4.3 N / 5 cm to 6.09 N / 5 cm per g / m 2 of area and is measured longitudinally as a stress of the high strength lightweight nonwoven fabric. ) Performs a water jet curing process such that) reaches a range of 0.45 N / 5 cm to 0.68 N / 5 cm per g unit of area at 5% elongation. 13. The method of claim 12, wherein the fibers or fibrils are provided under a deadlock or melt-blown method application. A method of using the high strength lightweight nonwoven according to any one of claims 1 to 3 for use in industrial coatings and for use in printed large fiber billboards such as coverings and banners for use in the building industry.