Synthetic insulator with improved flexibility

Abstract

The nonwoven fabric contains 20 to 80% by weight of meltblown fibers and 20 to 80% by weight of staple fibers based on the total weight of the nonwoven fabric. The meltblown fibers include polyethylene or a mixture of polyethylene and polypropylene, and the polyethylene has a melt index (I2) of 200 to 1000 g / 10 min. The nonwoven fabric may be useful as a thermal insulator and / or an acoustic insulator having improved flexibility.

Description

[Technical Field]

[0001] This disclosure relates to synthetic materials that are generally useful as thermal and / or acoustic insulators having improved flexibility. [Background technology]

[0002] Numerous natural and synthetic products exist that are useful as thermal and / or acoustic insulators. Natural down or silk is widely used due to its lightweight and soft nature, along with its good insulating properties. However, in addition to being a natural animal-based product, natural down feathers or silk compress when wet, for example after washing, and thus lose their insulating properties. Natural down or silk can also develop an unpleasant odor, especially when wet. Finally, the cost of natural down has increased dramatically in recent years.

[0003] Therefore, considerable research has been conducted to develop alternative solutions that have comparable insulation performance, are washable, and are more competitively priced. Currently, meltblown polypropylene mixed with polyester staple fibers is widely used as a thermal or acoustic insulator in the apparel, household, medical, and automotive industries. However, these products are not as soft as natural down feathers or silk. Therefore, there is a need for softer synthetic insulators that retain exemplary insulation properties. [Overview of the Initiative]

[0004] A nonwoven fabric is disclosed comprising, based on the total weight of the nonwoven fabric, 20 to 80% by weight of meltblown fibers containing polyethylene or a mixture of polyethylene and polypropylene, and 20 to 80% by weight of staple fibers. The polyethylene has a melt index (I2) of 200 to 1000 g / 10 min. [Brief explanation of the drawing]

[0005] [Figure 1]A schematic diagram of the drape test is shown below. [Figure 2] The sound absorption coefficients of CE-3, IE-1, and IE-2 at different frequencies, determined by the standing wave method, are shown. [Figure 3] The sound absorption coefficients of CE-5 and IE-3 at different frequencies are shown using the standing wave method. [Figure 4] The sound absorption coefficients of CE-5 and IE-3 at different frequencies, determined by the reverberation chamber method, are shown. [Modes for carrying out the invention]

[0006] As used in this disclosure, a meltblown is formed by extruding a molten material through a plurality of orifices to form a filament, while simultaneously bringing the filament into contact with air or another thinning fluid to thin it into fibers, and then collecting the layers of thinned fibers.

[0007] When used in this disclosure, meltblown fiber means a fiber prepared by a meltblown process.

[0008] When used in this disclosure in relation to fibers, diameter means the diameter of a fiber having a circular cross-section, or, in the case of a non-circular fiber, the length of the longest cross-sectional chord that can be formed across the width of the fiber.

[0009] The glass transition temperature (or T) of the polymers used in this disclosure g ) refers to the temperature at which, as the temperature rises, an amorphous polymer changes from being hard and relatively brittle or glassy to viscous or rubbery.

[0010] As used in this disclosure, polypropylene or propylene polymers mean polymers containing more than 50 mol% of units derived from propylene monomer. This includes propylene homopolymers or copolymers.

[0011] As used in this disclosure, polyethylene or ethylene-based polymers mean polymers containing more than 50 mol% of units derived from ethylene monomers. This includes ethylene-based homopolymers or copolymers.

[0012] As used in this disclosure, nonwoven fabrics mean webs or cloths having a structure of randomly inserted individual fibers or threads, as opposed to a knitted fabric in an identifiable manner.

[0013] Staple fibers refer to natural fibers, or, for example, the length cut from a manufactured filament. Staple fibers include natural and synthetic materials. Natural materials include cellulose fibers, as well as woven fibers such as cotton and rayon. Synthetic materials include non-absorbent synthetic polymer fibers, such as polyolefins, polyesters, polyacrylics, and polyamides.

[0014] Nonwoven fabric The nonwoven fabric may contain 20 to 80% by weight of meltblown fibers, based on the total weight of the nonwoven fabric. All individual values ​​and partial ranges of 20 to 80% by weight are disclosed and included herein. The nonwoven fabric may contain 40 to 60% by weight of meltblown fibers, based on the total weight of the nonwoven fabric. The nonwoven fabric may contain 30 to 70% by weight of meltblown fibers, based on the total weight of the nonwoven fabric. The nonwoven fabric may contain 50 to 70% by weight of meltblown fibers, based on the total weight of the nonwoven fabric.

[0015] Staple fibers are mixed with meltblown fibers. The nonwoven fabric may contain 20 to 80% by weight of staple fibers, based on the total weight of the nonwoven fabric. All individual values ​​and partial ranges of 20 to 80% by weight are disclosed and included herein. For example, the nonwoven fabric may contain 30 to 70% by weight of staple fibers, based on the total weight of the nonwoven fabric. The nonwoven fabric may contain 40 to 60% by weight of staple fibers, based on the total weight of the nonwoven fabric. The nonwoven fabric may contain 30 to 50% by weight of staple fibers, based on the total weight of the nonwoven fabric.

[0016] The thickness of the non-woven fabric may be 1 mm to 5 mm for a basis weight of 100 grams per square meter (gsm). All individual values and sub-ranges of 1 mm to 5 mm are included and disclosed herein. The non-woven fabric may be 2 mm to 3 mm for a basis weight of 100 gsm. The non-woven fabric may have a bulk density of 20 to 100 g / l. All individual values and sub-ranges of 20 to 100 g / l are included and disclosed herein. The non-woven fabric may have a bulk density of 20 to 40 g / l or 30 to 40 g / l.

[0017] The non-woven fabric may have a basis weight of 50 to 350 gsm. All individual values and sub-ranges of 50 to 350 gsm are included and disclosed herein. For example, the non-woven fabric may have a basis weight of 50 to 100 gsm, 50 to 70 gsm, 250 to 325 gsm, or 290 to 325 gsm.

[0018] The non-woven fabric has a basis weight of 60 to 67 gsm and may have a thermal resistance of 0.200 (m 2 K) / W or more. The non-woven fabric has a basis weight of 60 to 67 gsm and may have a thermal resistance of 0.210 (m 2 K) / W or more. The non-woven fabric has a basis weight of 60 to 67 gsm and may have a thermal resistance of 0.200 to 0.300 (m 2 K) / W. All individual values and sub-ranges are incorporated and disclosed. For example, the non-woven fabric has a basis weight of 60 to 67 gsm and may have a thermal resistance of 0.200 to 0.250 (m 2 K) / W.

[0019] The non-woven fabric has a basis weight of 300 gsm and may have a thermal resistance of 0.900 (m 2 K) / W or more. The non-woven fabric has a basis weight of 300 gsm and may have a thermal resistance of 0.950 (m 2 K) / W or more. The non-woven fabric has a basis weight of 300 gsm and may have a thermal resistance of 0.900 to 1.500 (m 2 K) / W. All individual values and sub-ranges are incorporated and disclosed. For example, the non-woven fabric has a basis weight of 300 gsm and may have a thermal resistance of 0.900 to 1.000 (m 2It may have a heat resistance of K) / W.

[0020] Melt blown fibers made from polyethylene or a mixture of polyethylene and polypropylene Melt blown fibers can be produced by extruding a fiber-forming material through a die orifice into a gas stream, as will be described in more detail below. Typically, melt blown fibers are very long and have an indefinite length compared to staple fibers. Melt blown fibers may have a diameter of less than 10 μm.

[0021] Melt blown fibers may include polyethylene or a mixture of polyethylene and polypropylene. Common forms of polyethylene known in the art include, but are not limited to, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), single-site catalyst linear low density (m-LLDPE) including both linear and substantially linear low density resins, medium density polyethylene (MDPE), and high density polyethylene (HDPE).

[0022] Additionally, as described herein, the term LDPE may also be referred to as a high pressure ethylene polymer or highly branched polyethylene, and is defined to mean that the polymer is partially or fully homopolymerized or copolymerized in an autoclave or tubular reactor at a pressure above 14,500 psi (100 MPa) using a free radical initiator such as a peroxide (see, for example, U.S. Patent No. 4,599,392). LDPE resins typically have a density of 0.91 g / cm 3 ~0.94 g / cm3 It has a density within the range.

[0023] The term LLDPE, as used herein, may include resins prepared using the Ziegler-Natta catalyst system, as well as resins prepared using single-site catalysts, including but not limited to bis-metallocene catalysts, phosphine imines, and geometrically constrained catalysts (sometimes referred to as "m-LLDPE"), and resins prepared using post-metallocene molecular catalysts, including but not limited to bis(biphenylphenoxy) catalysts (also referred to as polyvalent aryloxy ether catalysts). LLDPE comprises linear, substantially linear, or heterogeneous ethylene copolymers or homopolymers. LLDPE contains fewer long-chain branches than LDPE and includes substantially linear ethylene polymers as further defined in U.S. Patents 5,272,236, 5,278,272, 5,582,923, and 5,733,155; homogeneously branched ethylene polymers such as those described in U.S. Patent 3,645,992; heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent 4,076,698; and blends thereof (such as those disclosed in U.S. Patents 3,914,342 or 5,854,045). LLDPE resins can be produced via gas-phase, solution-phase, or slurry polymerization, and any combination thereof, using any type of reactor or reactor configuration known in the art.

[0024] Additionally, as used herein, the term HDPE generally refers to a material prepared using a Ziegler-Natta catalyst, a chromium catalyst, or even a metallocene catalyst, with a concentration of approximately 0.940 g / cm³. 3 This refers to polyethylene having the above density.

[0025] Meltblown fibers may have a fiber diameter of less than 10 μm. Meltblown fibers may have a fiber diameter of less than 5 μm. Meltblown fibers may have a fiber diameter of 1 μm to 10 μm. All individual values ​​and subranges of 1 μm to 10 μm are incorporated and disclosed. For example, meltblown fibers may have a fiber diameter of 2 to 5 μm.

[0026] Meltblown fibers may contain polyethylene or a mixture of polyethylene and polypropylene. Meltblown fibers may contain 40–60% by weight of polypropylene based on the total weight of the meltblown fibers. All individual values ​​and subranges of 40–60% by weight of polypropylene are incorporated and disclosed. For example, meltblown fibers may contain 45–55% by weight of polypropylene based on the total weight of the meltblown fibers. Meltblown fibers may contain 50% by weight of polypropylene based on the total weight of the meltblown fibers.

[0027] Meltblown fibers may contain 20 to 100% by weight of polyethylene, based on the total weight of the meltblown fibers. For example, meltblown fibers may contain polyethylene ranging from a lower limit of 20, 25, 30, 40, 45, 50, 55, 60, 75, 80, 90, 95, or 99% by weight, to an upper limit of 100, 99, 95, 90, 80, 75, 60, 55, 40, 35, 30, or 25% by weight, based on the weight of the meltblown fibers.

[0028] The meltblown fibers may contain polyethylene having a melt index (I2) of 200 to 1000 g / 10 min. All individual values ​​and partial ranges of 200 to 1000 g / 10 min are disclosed and incorporated herein. The meltblown fibers may also contain polyethylene having a melt index (I2) of 200 to 700 g / 10 min or 200 to 500 g / 10 min.

[0029] Staple fiber Staple fibers may be added as solids mechanically cut to a predetermined length. Staple fibers may have a fiber diameter of 10 μm or more. Staple fibers may have a diameter of 10 to 50 μm. All individual values ​​and subranges of 10 to 50 μm are disclosed and included herein. Staple fibers may have a diameter of 10 to 25 μm or 25 to 50 μm. The length of the staple fibers may be 30 mm to 60 mm. All lengths of 30 mm to 60 mm are included herein. Staple fibers may be 35 to 55 mm, 40 to 50 mm, or 35 to 45 mm. The thickness of the fiber can also be defined by denier. Denier defines the mass density of the fiber from which the cloth is made and indicates the fineness of the fiber. Denier is equal to the mass in grams per 9000 meters of yarn. Staple fibers generally have a denier of 3g / 9000m (3D) or more, or 4g / 9000m (4D) or more. The denier is typically less than 10g / 9000m (10D).

[0030] Staple fibers may include synthetic polymer materials. Staple fibers may include polyethylene terephthalate, polyester, polyethylene, polypropylene, copolyester, polyamide, PAN, cellulose, or mixtures thereof. Staple fibers that can melt-bond to each other and / or to melt-blown fibers may be selected. Staple fibers that cannot melt-bond to each other and / or to melt-blown fibers may be selected. Staple fibers may be crimped. Crimped staple fibers may have a continuous, wavy, curled, or jagged profile along their length. Stabilized fibers may have 8 to 14 crimps per inch of staple fiber.

[0031] Nonwoven fabric additives Nonwoven fabrics may contain additives that improve mechanical properties, aging properties, coloration, surface properties, or other properties of interest. Suitable additives include fillers, nucleating agents, electrostatic enhancement additives, light stabilizers, curing agents, surfactants, and surface treatment agents. Those skilled in the art will be familiar with the amounts of various additives that may be added, and other types that may be included.

[0032] Nonwoven fabric manufacturing process Meltblown fibers may be extruded through a die having closely spaced orifices and thinned by a converging flow of high-speed, hot air to form fine fibers. These fibers may then be collected on a surface. The meltblown fibers should be continuous.

[0033] A flow of thermoplastic polymer may be supplied to a manifold. The flow may then be supplied to a die. Air slots located on either side of the die orifice through which the thermoplastic polymer passes as it exits the die direct uniform heated air at high speed into the extrusion molten flow. The hot, high-speed air draws in and thins the extruded thermoplastic polymer material, which solidifies after traveling a short distance from the spinneret. The high-speed air can create turbulence between the spinneret and the collector surface, mixing the meltblown fibers in the airflow.

[0034] Polyethylene and polypropylene blended fibers can be produced by pre-blending two pellets, then feeding both together from separate hoppers or from the same hopper into a single extruder, and spinning both together from a die.

[0035] The polymer material is fed from the hopper and extruder through the inlet to the melt blow die and can then flow through the die cavity. The polymer material can exit the die cavity through a row of orifices of varying sizes arranged in a row across the front end of the die cavity. An airflow of high-speed heated air can thin the filaments. The orifices may include rows of larger and smaller orifices. As will be understood by those skilled in the art, larger diameter fibers may be extruded from larger diameter orifices, and smaller diameter fibers may be extruded from smaller diameter orifices.

[0036] Staple fiber filaments can be supplied from a hopper and extruder to a large die cavity. A high-speed heating airflow may thin the staple fiber filaments and mix them with meltblown filaments exiting the die cavity, which can be oriented perpendicular to the staple fiber die cavity. As will be apparent to those skilled in the art, the level of entanglement between the meltblown and stabilizing fibers can be altered by adjusting the orientation of the meltblown and stabilizing die cavity relative to each other. If the staple fibers exit the staple fiber die cavity horizontally, the meltblown fibers must exit the meltblown die cavity perpendicularly.

[0037] Use of nonwoven fabric The disclosed nonwoven fabric may be used in several thermal and acoustic applications. For example, the disclosed nonwoven fabric may be used in battery compartments, engine compartments, car doors and ceilings, insulation applications in railway vehicles, car trunks, car hoods, building and utility wraps, furniture upholstery materials, HVAC systems, and jacket linings or fillers. The nonwoven fabric may be used as a monolithic layer. The monolithic layer may be surrounded by cavity walls. An outer layer may be wrapped around the nonwoven fabric to completely enclose it. An adhesive layer may be applied to one or more surfaces of the nonwoven fabric. A release liner may be attached to one or more adhesive layers. The adhesive layer may be pressure-sensitive, curable, or solidifying. The adhesive layer may consist of a binder.

[0038] Test method density Density is measured according to ASTM D-792 and expressed in grams per cubic centimeter (g / cc).

[0039] Melt index and melt flow rate (MFR) The melting index (I2) is measured at 190°C with 2.16 kg of material according to ASTM D-1238. The value is reported as g / 10 min, corresponding to the grams eluted per 10 minutes. The melt flow rate is measured for polypropylene or propylene-based polymers at 230°C with 2.16 kg of material.

[0040] Basis weight Place the sample in 100 cm 2 Cut the sample into pieces and weigh them on a balance. Then, multiply this weight by 100 to convert the measurement to grams per square meter (gsm).

[0041] Thermal insulation performance Thermal insulation performance is measured according to GB / T11048-2018. Thermal resistivity, CLO value, insulation coefficient, and thermal conductivity are recorded.

[0042] sound acoustic performance Acoustic performance is measured in the frequency range of 100–6300 Hz according to GB / T18696.1–2004. The sound absorption coefficient is measured using both the standing wave tube method and the reverberation chamber method.

[0043] Flexibility (drape) performance An example of a drape test can be seen in Figure 1. A 16 cm wide sample is placed on the edge of a table, with 5 cm extending over the edge. The horizontal distance (L) between the pendent end of the sample and the table is measured, along with the vertical distance between the edge of the table and the end of a virtual line L from the pendent end to the table. The angle (a) between the nonwoven fabric and the vertical surface of the table is calculated. A smaller angle indicates better drape. [Examples]

[0044] The following embodiments are provided to further illustrate the description and claims. They should not be construed as limiting the disclosure. The raw materials used are listed in Table 1 below.

[0045] [Table 1]

[0046] EMBR-1 Production The experimental ethylene / alpha-olefin interpolymer meltblown fiber resin 1 (EMBR-1) is produced in a single reactor configuration using ethylene, 1-octene, and a high-purity isoparaffin solvent with a narrow boiling point range, purified with molecular sieves. Hydrogen is supplied pressurized as high-purity grade and is not further purified. The monomer feed stream to the reactor is pressurized to a pressure higher than the reaction pressure by a mechanical compressor. The solvent and comonomer feeds are pressurized to a pressure higher than the reaction pressure by pumps. Individual catalyst components are manually batch diluted to specified component concentrations using purified solvents and pressurized to a pressure higher than the reaction pressure. All reaction feed streams are measured using a mass flow meter and independently controlled by computer-automated valve control systems.

[0047] The continuous solution polymerization reactor consists of a liquid-filled, non-adiabatic, isothermal circulating loop reactor that mimics a continuously stirred tank reactor (CSTR) with heat removal. All fresh solvent, monomer, comonomer, hydrogen, and catalyst feeds are independently controlled. The entire fresh feed stream (solvent, monomer, and hydrogen) to the reactor is temperature-controlled by passing the feed stream through a heat exchanger. All additional feeds to the polymerization reactor are injected into the reactor at two locations, with approximately equal reactor volumes between each injection point. Fresh feed is controlled by each injector receiving half of the total mass flow of the fresh feed.

[0048] The mass flow ratio of feed solvent to ethylene in the first reactor is 3.8. The mass flow ratio of feed comonomer to ethylene in the first reactor is 0.20. The mass flow ratio of feed hydrogen to ethylene in the first reactor is 3.0 × 10⁻⁶. -4 The temperature of the first reactor is 155°C, the pressure of the first reactor is 34 bar, and the ethylene conversion percentage of the first reactor is 86.1.

[0049] The catalyst components are injected into the polymerization reactor through specially designed injection needles. The main catalyst component feed is computer-controlled to maintain the reactor monomer conversion at a specific target value. Co-catalyst components are supplied based on a calculated specific molar ratio to the main catalyst component. Immediately after the injection point of each reactor feed, the feed stream is mixed with the contents of the circulating polymerization reactor, which has a static mixing element. The reactor contents are continuously circulated at the temperature of the coolant side, which plays a role in maintaining an isothermal reaction environment at a specified temperature, through a heat exchanger, which plays a role in removing most of the reaction heat. The circulation around the reactor loop is provided by pumps.

[0050] The catalyst type for the first reactor is [N-(1,1-dimethylethyl)-1,1-dimethyl-1-[(1,2,3,4,5-etha)-2,3,4,5-tetramethyl-2,4-cyclopentadiene-1-yl]silanaminato(2-)-kappaN][(1,2,3,4-etha)-1,3-pentadiene]-titanium. The co-catalyst-1 type for the first reactor is bis(hydrogenated tallow alkyl)methylammonium tetrakis(pentafluorophenyl)borate(1-), while the co-catalyst-2 type for the first reactor is branched, cyclic, and linear aluminoxanes, iso-BuMe; modified methylaluminoxane. The co-catalyst-1 to catalyst molar ratio for the first reactor is 1.2, and the co-catalyst-2 to scavenger molar ratio for the first reactor is 5.0. The residence time in the first reactor is 13.1 minutes.

[0051] The final reactor effluent enters an area where it is deactivated by the addition and reaction of a suitable reagent (water). Other additives are added at this same reactor outlet location to stabilize the polymer. A water-to-active catalyst ratio of at least 10x molar is available, and conditions are selected to halt polymerization in the reactor effluent. This aspect is important to ensure that the polymer material has a narrow molecular weight distribution and that a narrow compositional distribution is maintained.

[0052] Following catalyst deactivation and additive addition, the reactor effluent enters a devolving system where the polymer is removed from the non-polymer stream. The isolated polymer melt is processed and pelletized according to the instructions provided in International Publication 2015 / 191066, pp. 6, lines 23-28, pp. 8, lines 11-16, and pp. 11, lines 3-25. The non-polymer stream passes through various instruments that separate the majority of the ethylene removed from the system. The majority of the solvent and unreacted comonomers are recycled back into the reactor after passing through a purification system. Small amounts of solvent and comonomers are purged from the process.

[0053] Nonwoven fabric production Nonwoven fabrics CE-1 and CE-2 are prepared on a Reicofil pilot line with a width of 0.6 m. All other nonwoven fabrics are prepared on a separate meltblown production line with a width of 1.6 m and a pore size of 0.3 mm. The air temperature is set to 240-270°C depending on the melting index of the meltblown resin. Insulation cotton is produced on a 1.6 m wide meltblown machine. Polyethylene terephthalate staple fibers are incorporated through a side feed unit at a rate of 15 kg / hour. The extruder temperature is set to 170°C in the first region, 180°C in the second region, 200°C in the third region, 210°C in the fourth region, and 220°C in the fifth region, from the hopper to the nozzle. For polypropylene, the melt pump temperature is set to 225°C, and for polyethylene, the melt pump temperature is set to 220°C. The high-temperature air temperature is set to 230°C for polypropylene and 220°C for polyethylene.

[0054] Table 2 lists nonwoven fabrics that do not contain polyethylene terephthalate. Both CE-1 (comparative example 1) and CE-2 (comparative example 2) are pure meltblown nonwoven fabrics that do not contain polyethylene terephthalate staple fibers. These samples were found not to be sufficiently bulky as insulating cotton. This lack of bulk resulted in inefficient sound and heat absorption. Comparative example 2 used a low melt index polyethylene product and had to be processed at 50% of the yield compared to CE-1. This resulted in a larger fiber size.

[0055] [Table 2]

[0056] Table 3 shows the results for comparative samples and samples of the present invention. CE-3 and CE-5 (Comparative Examples 3 and 5) are examples of prior art solutions using melt-blown polypropylene with polyethylene terephthalate staple fibers having different basis weights. CE-4 (Comparative Example 4) is a commercially available silk quilt used for reference. IE-1 and IE-3 (Inventive Examples 1 and 3) are examples of the present invention using polyethylene melt-blown instead of polypropylene having different basis weights to achieve improved comfort and flexibility. IE-2 and IE-4 (Inventive Examples 2 and 4) are another pair of examples of the present invention having different basis weights, in which both polyethylene and polypropylene melt-blown are used to achieve a balance of strength and flexibility.

[0057] [Table 3]

[0058] Table 4 shows the angles calculated in the drape tests described above. The polyethylene sample (IE-1) had the best drape, while the polypropylene (CE-3) had the worst drape. The polyethylene-polypropylene blend (IE-2) was between these two extremes. CE-4 had drape comparable to IE-1, but IE-1 had better thermal insulation performance, as shown in the next section.

[0059] [Table 4]

[0060] Thermal insulation data is shown in Table 5. Lower thermal conductivity, along with higher thermal resistivity, CLO value, and insulation ratio, indicates better thermal insulation. Examples of the present invention (IE-1 / IE-2) exhibit better thermal insulation performance than Comparative Example 4 (CE-4), despite CE-4 having a higher basis weight, demonstrating the advantage of better insulation efficiency for the examples of the present invention listed herein. CE-3 has higher insulation performance than IE-1 / IE-2 because it has a higher basis weight (along with much higher rigidity, as mentioned above). Comparing examples of IE-3 / IE-4 / CE-5 having the same basis weight (300 gsm), examples of the present invention (IE-3 / IE-4) exhibit better or equivalent thermal insulation performance compared to Comparative Example (CE-5).

[0061] [Table 5]

[0062] The acoustic performance is shown in Figures 2, 3, and 4. As can be seen in Figure 2, the acoustic coefficients of IE-1 and IE-2, when measured using the GB / T 18696.1-2004 standard, are comparable to those of CE-3 in the 100-10000 Hz range. This is despite the fact that the basis weights of IE-1 and IE-2 are approximately 30 gsm smaller than those of CE-3.

[0063] Figure 3 shows that when comparing IE-3 to CE-5 using the standing wave method with the same basis weight, IE-3 has a higher sound absorption coefficient than CE-5 in the 100–7000 Hz range, demonstrating that such an advantage exists in the low-frequency range. Figure 4 shows that the same is true for IE-3 when compared to CE-5, provided that the sound absorption coefficient is measured according to the reverberation chamber method. Examples of the inventions of this application include the following: [1] Nonwoven fabric, a. Based on the total weight of the nonwoven fabric, 20 to 80% by weight of meltblown fibers, wherein the meltblown fibers include polyethylene or a mixture of polyethylene and polypropylene, and the polyethylene has a melt index (I) of 200 to 1000 g / 10 min. 2 a. A nonwoven fabric comprising melt-blown fibers having ) and 20 to 80% by weight of staple fibers, based on the total weight of the nonwoven fabric. [2] The nonwoven fabric according to [1] above, comprising: a. 30 to 70% by weight of meltblown fibers based on the total weight of the nonwoven fabric; and b. 30 to 70% by weight of staple fibers based on the total weight of the nonwoven fabric. [3] The nonwoven fabric according to [1] above, comprising: a. 40 to 60% by weight of meltblown fibers based on the total weight of the nonwoven fabric; and b. 40 to 60% by weight of staple fibers based on the total weight of the nonwoven fabric. [4] The nonwoven fabric according to any one of the above [1] to [3], wherein the staple fibers include polyester, polypropylene, PAN, polyamide, cellulose, or a mixture thereof. [5] a. Meltblown fibers comprising 50 to 70% by weight of meltblown fibers based on the total weight of the nonwoven fabric, wherein the meltblown fibers comprise 40 to 60% by weight of polyethylene and 40 to 60% by weight of polypropylene based on the total weight of the meltblown fibers; and b. Staple fibers comprising 30 to 50% by weight based on the total weight of the nonwoven fabric, as described in [1] above. [6] The thermal resistance of the nonwoven fabric is 0.200 (m²) at a basis weight of 60-67 gsm. 2 (k) / W or 0.900(m²) with a basis weight of 300 gsm 2 A nonwoven fabric as described in any one of the above [1] to [5], wherein the ratio of k) / w is greater than [1] / w. [7] The nonwoven fabric according to any one of the above [1] to [6], wherein the meltblown fibers have a fiber diameter of less than 10 μm. [8] The nonwoven fabric according to any one of the above [1] to [6], wherein the staple fibers have a fiber diameter of 10 to 50 μm.

Claims

1. A monolithic nonwoven fabric, a. Based on the total weight of the nonwoven fabric, 20 to 80% by weight of meltblown fibers, wherein the meltblown fibers include polyethylene or a mixture of polyethylene and polypropylene, and the polyethylene has a melt index (I) of 200 to 1000 g / 10 min. ２ A meltblown fiber having, b. Based on the total weight of the nonwoven fabric, 20 to 80% by weight of staple fibers containing polyester, A monolithic nonwoven fabric containing [a specific material].

2. a. Based on the total weight of the nonwoven fabric, 30 to 70% by weight of meltblown fibers, b. The monolithic nonwoven fabric according to claim 1, comprising 30 to 70% by weight of staple fibers based on the total weight of the nonwoven fabric.

3. a. Based on the total weight of the nonwoven fabric, 40 to 60% by weight of meltblown fibers, b. The monolithic nonwoven fabric according to claim 1, comprising 40 to 60% by weight of staple fibers based on the total weight of the nonwoven fabric.

4. The monolithic layer nonwoven fabric according to any one of claims 1 to 3, wherein the staple fibers include polyethylene terephthalate (PET).

5. a. Meltblown fibers comprising 50 to 70% by weight of the nonwoven fabric based on the total weight of the nonwoven fabric, wherein the meltblown fibers comprise 40 to 60% by weight of polyethylene and 40 to 60% by weight of polypropylene based on the total weight of the meltblown fibers, b. The monolithic nonwoven fabric according to claim 1, comprising 30 to 50% by weight of staple fibers based on the total weight of the nonwoven fabric.

6. The thermal resistance of the aforementioned nonwoven fabric is 0.200 (m²) at a basis weight of 60-67 gsm. ２ (k) / W or 0.900 (m) with a basis weight of 300 gsm ２ A monolithic layer nonwoven fabric according to any one of claims 1 to 3 and 5, wherein the ratio of k / w is greater than .

7. The monolithic layer nonwoven fabric according to any one of claims 1 to 3 and 5, wherein the meltblown fibers have a fiber diameter of less than 10 μm.

8. The monolithic nonwoven fabric according to any one of claims 1 to 3 and 5, wherein the staple fibers have a fiber diameter of 10 to 50 μm.

9. A monolithic nonwoven fabric according to any one of claims 1 to 3 and 5, for use in applications involving thermal insulation and / or acoustic performance.

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