JP2003301357A - High-temperature thermoformable nonwoven fabric for three-dimensional molding and sound absorbing material using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric for three-dimensional molding having excellent heat resistance, good follow-up properties to the shape of a molded product to be obtained by molding processing and excellent screening properties especially when used as a sound absorbing material. <P>SOLUTION: The nonwoven fabric for the three-dimensional molding comprises fibers composed of a mixed polymer of 75-98 mass% of polyethylene terephthalate and 25-2 mass% of a polyolefinic polymer as at least one component. The nonwoven fabric for the three-dimensional molding satisfies (1) to (3): (1) ≤10 μm average fiber diameter, (2) ≥210°C flow starting temperature of the mixed polymer and (3) ≤10% dry heat area shrinkage percentage at 120°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven fabric for three-dimensional molding, and more particularly to a non-woven fabric for three-dimensional molding which has excellent heat resistance and excellent conformability to a complicated molding process. Furthermore, the nonwoven fabric for three-dimensional molding of the present invention can be subjected to deep-drawing molding, and is useful as a sound absorbing material having a complicated shape.

[0002]

2. Description of the Related Art Nonwoven fabrics made of short fibers such as glass fibers have been widely used as sound absorbing materials for automobiles and construction applications. These non-woven fabrics have a small fiber diameter to increase the air passage resistance in order to improve the sound absorption performance,
Methods such as increasing the basis weight have been adopted. As a result, when high sound absorption performance is required, the fiber diameter is 15
A thick and heavy short fiber non-woven fabric having a thickness of about μm and a basis weight of 500 to 5000 g / m ² was used. However, when these non-woven fabrics are used as a sound absorbing material where they can be seen from the outside or when they are used around the moving parts of a machine,
It was necessary to prevent the short fibers from falling off during the thermoforming process, and it was necessary to adjust the shape to the shape of the place of use, which was inconvenient in practice.

Therefore, spunbonded nonwoven fabrics have been used in such places. However, spunbonded non-woven fabrics generally have high strength, low elongation, and high elongation modulus, so when deep drawing is performed during molding, they may partially float or the bulk of the molded product may be reduced. It is very disadvantageous because you cannot earn money. Further, since spunbonded nonwoven fabric has a low concealing property, it has been unavoidable that the spunbonded nonwoven fabric is used as a laminated composite with other nonwoven fabrics in order to improve it. For example, a method of laminating and integrating a non-woven fabric made of ultrafine fibers is known. However, since these laminated non-woven fabrics also have a high elongation modulus of spunbonded non-woven fabrics, they are poor in shape-following property at the time of molding. There was a problem that the volume feeling was lacking, the texture became hard and the applications were limited.

In order to solve these problems, it is necessary to use a nonwoven fabric which is easy to stretch and has a high concealing property. As a method of manufacturing such a non-woven fabric relatively easily, a molten polymer is discharged from an orifice, thinned into fibers by a high-temperature high-speed gas ejected from the vicinity thereof, and collected on a belt conveyor such as a wire mesh to form a non-woven fabric. The so-called melt-blowing method is known, and various melt-blown nonwoven fabrics such as polyolefins, polyamides and polyurethanes are produced.

In recent years, various melt-blown nonwoven fabrics have been adopted for use as sound absorbing materials, especially sound absorbing materials for automobiles, etc., but from the viewpoint of energy saving and environmental protection, they are composed of recyclable polymers or polymers containing no toxic gas at the time of combustion. Products are in demand. Therefore, having a heat resistance that can be subjected to molding processing at a high temperature, and polyester can be cited as a recyclable general-purpose polymer, in particular, having a higher heat resistance, from the viewpoint of a relatively inexpensive polymer, Polyethylene terephthalate is drawing attention.

However, polyethylene terephthalate (hereinafter abbreviated as PET) which can be said to be a representative of polyester
At present, the melt-blown non-woven fabric made of is rarely manufactured. The reason for this is that since PET has a slower crystallization rate than other crystalline polymers that are often used for melt blowing, it is possible to form fine fibers when produced under normal melt blowing conditions, but the crystals are melted during melt blowing. The degree of chemical conversion cannot be sufficiently increased, and therefore the thermal stability is low, and when left free at a temperature above the glass transition point (70 to 80 ° C), the fiber contracts greatly and is extremely It becomes a big problem. In order to improve this point, JP-A-3-45768 proposes a method of heat-treating the melt-blown web under tension to appropriately increase crystallization. However, this method requires increasing the number of heat treatment steps, and at the same time, the obtained product is likely to generate spherulites, or has a higher heat shrinkage rate than the melt blown nonwoven fabric manufactured from other easily crystallized polymers, Only inferior products with low strength and hard texture can be obtained. Therefore, when molding is performed using such a melt-blown nonwoven fabric as a surface material, there is a problem that the nonwoven fabric shrinks and becomes brittle due to heat during processing and easily breaks. A non-woven fabric having both processability has been desired.

[0007]

The object of the present invention is to have excellent heat resistance and good followability to a molded product having a complicated shape, and particularly excellent when used as a sound absorbing material. It is to provide a nonwoven fabric for three-dimensional molding having a shielding property.

[0008]

[Means for Solving the Problems] That is, the present invention provides a three-dimensional molding non-woven fabric comprising at least one component of a fiber composed of a mixed polymer of 75 to 98% by mass of polyethylene terephthalate and 25 to 2% by mass of a polyolefin-based polymer, The nonwoven fabric for three-dimensional molding is characterized by satisfying the following 1) to 3). 1) The average fiber diameter is 10 μm or less, 2) the flow initiation temperature of the mixed polymer is 210 ° C. or higher, and 3) the dry heat area shrinkage ratio at 120 ° C. is 10% or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a non-woven fabric for three-dimensional molding, which has good productivity by blending PET with a specific amount of a polyolefin-based polymer and is excellent in morphological stability, heat resistance, shielding property, and heat molding followability. It is obtained, and in order to achieve such an object, it is preferable to manufacture by a melt blow method. Hereinafter, the present invention will be described in detail.

The non-woven fabric for three-dimensional molding of the present invention contains PET as a main component. Generally, when PET is to be made into a non-woven fabric by the melt blow method, it is subject to melt blow conditions in other easily crystallizable polymers such as polypropylene. In comparison, the heat shrinkage of the obtained meltblown nonwoven fabric cannot be reduced unless the polymer is melt blown with high polymer viscosity and high pressure air. Moreover, as described above, under such conditions, productivity and operational stability are lacking. The present inventors have studied to solve these problems by using relatively low pressure air. That is, the melt viscosity of the entire system is lowered by blending an appropriate amount of a polyolefin-based polymer that is incompatible with PET, has a high crystallization rate, and has a sufficiently low melt viscosity ”
By making the “thickening effect”, it becomes easy to make PET into fine fibers, and it is possible to obtain the nonwoven fabric for three-dimensional molding which is the object of the present invention. The polymer blended with PET is the same polyester-based polymer. Some polybutylene terephthalate (PBT) having a similar chemical structure cannot achieve the purpose, probably because they inhibit the crystallization ability of each other.

Then, as a result of the examination by the present inventors, PET was obtained.
75 to 98% by mass, and polyolefin polymer to 2
It has been found that the use of a polymer blended with 25% by mass is most effective for achieving the above object. Preferably,
PET 85-95% by mass, polyolefin-based polymer 5
Is about 15% by mass. Here, the PET used in the nonwoven fabric for three-dimensional molding of the present invention is basically any general-purpose product, but one having an intrinsic viscosity of 1.2 or less is preferable, and 0.5 to 0 is more preferable. .9. If the intrinsic viscosity exceeds 1.2, the polymer viscosity may be too high to obtain a fine fiber diameter when produced by the melt blow method. In the present invention, recycled PET may be used. Recycled PET is obtained by shearing, crushing, and melting and solidifying fibers, films, molded products, and the like.

The polyolefin-based polymer used in the present invention includes polyethylene (particularly LLDPE),
Polypropylene (PP), Polymethylpentene (PM
P) and the like are effective, and PP and PMP are particularly preferable in that they have good spinnability under low melt viscosity. In order to sufficiently obtain the "thickening effect" due to these blended polymers, it is preferable to use a low melt viscosity grade. For example, in the case of PP, it is preferable to use a melt index at 230 ° C. of 100 or more.
It is preferable in that the polymer stream can be easily made into fine fibers even with a relatively weak force of low-pressure air of 00 kPa or less.

Further, by improving the fluidity of PET as well, the blending uniformity with the polyolefin-based polymer is further improved, and even at a higher polyolefin-based polymer mixing ratio, the low-pressure air promotes the formation of fine fibers, and It is possible to manufacture a three-dimensional molding non-woven fabric composed of fine fibers. This is also advantageous for ensuring the concealing property of the nonwoven fabric described later. For this purpose, it is important to properly adjust the water content of PET as a raw material. Usually, in the melt spinning of PET, the water content of PET charged into an extruder is usually 50 ppm or less, and it is said that the larger this value, the lower the spinning stability. However,
This is not always the case in the meltblowing method, and particularly in the present invention, this value is 100 to 50.
When the content is 0 ppm, it becomes possible to mix the polyolefin-based polymer more uniformly while ensuring good melt-blowing spinnability, and it becomes possible to make the fiber finer, so that good hiding property can be ensured. is there. This is because by allowing the polymer to contain an appropriate amount of water,
During the melt extrusion, the hydrolysis of the polymer is promoted, and the oligomer produced thereby acts to secure the fluidity of the entire molten polymer, thereby exhibiting good fluidity. However, if the water content is less than 100 ppm,
When the flowability of PET is low and the polyolefin content is low, it may be difficult to reduce the thickness. Further, when the content is 500 ppm or more, the spinning itself becomes unstable, so that the nozzle becomes dirty,
Occurrence of agglomerated polymer particles called shots may occur, and it may be difficult to manufacture a nonwoven fabric.

In the present invention, the reason why the nonwoven fabric for three-dimensional molding having good thermal morphological stability is obtained by blending the polyolefin polymer is that polyolefin is PET.
The mixed morphology of islands and islands dispersed as fine island components in the continuous sea phase of (1) and (3) each crystallize appropriately, so even if each amorphous molecule tries to move and shrink due to heating, this crystal part It is presumed that the non-woven fabric can be obtained as a constraint point that suppresses the molecular movement, and a non-woven fabric whose thermal shrinkage is suppressed to be small. However, if the blending ratio of the polyolefin-based polymer is too small, the melt viscosity of the entire system will not be sufficiently lowered, and it will be difficult for the weak force of the low-pressure air to be sufficiently thinned into fibers, and at the same time, even if the air amount is considerably increased, the PET Although oriented crystallization becomes difficult to proceed, and although the heat shrinkage rate is small, when heat-treated at a temperature above the glass transition point by heat treatment or the like, agglomeration between fibers occurs and the nonwoven fabric becomes a paper-like rough texture. If the amount of air is further increased, the fibers in the web will scatter, making stable collection difficult. From these points, the lower limit of the blending ratio of the polyolefin-based polymer is 2%. On the other hand, when the mixing ratio of the polyolefin-based polymer becomes large, it becomes difficult to uniformly finely disperse the polyolefin-based polymer in PET, and thus the spinnability is reduced as is the case with ordinary blended spinning, and the It becomes difficult to obtain a melt-blown nonwoven fabric, and it becomes difficult to stably obtain a melt-blown nonwoven fabric. From this point, it is important that the blending ratio of the polyolefin-based polymer is 25% by mass or less.

If the mixed state of PET and the polyolefin-based polymer is non-uniform and the polyolefin-based polymer is present in the PET in the form of large lumps, so-called shots are likely to occur due to poor thinning, and stable melt blowing cannot be performed. It is desirable to finely disperse the base polymer almost uniformly. Any mixing method may be used as long as it can finely disperse the polyolefin-based polymer in the PET in a substantially uniform manner. It is preferable that the mixture is mixed in the form of pellets and melt-kneaded, or the kneaded product is further pelletized and used. In such a method, a special apparatus is not required, and the conventional melt blowing apparatus for a single component can be used as it is, which is advantageous in terms of the apparatus.

As a spinning head for carrying out the present invention, a conventional spinning head can be used. According to the method of the present invention, since the melt viscosity of the mixed polymer is sufficiently reduced, the single hole discharge amount is 0.2 to 1.0 g.
Melt blowing can be performed stably even in the range of not more than / minute. Even if the discharge amount is reduced to some extent, stable spinning can be performed, but production efficiency may be reduced. On the other hand, if the single-hole discharge rate exceeds 1.0 g / min, it is difficult for the low-pressure air to make fine fibers, and it is necessary to increase the air amount in order to make fine fibers sufficiently. In this case, if the amount of air is too large, the above-mentioned problem occurs and the production tends to be unstable. Further, the air pressure is preferably 1 kPa or more, and if it is lower than this, the fine fiberization does not proceed sufficiently.

The temperature at which the polymer is melted and the temperature at the spinneret part are preferably low in the range that satisfies the purpose from the viewpoint of deterioration of the polymer, so that the melt viscosity of the entire system in the spinneret is 10 to 50 Pa.s. A wide temperature range is particularly preferred.

The fibers constituting the nonwoven fabric for three-dimensional molding of the present invention thus obtained have an average fiber diameter of 10 μm or less, preferably 1 to 3 μm. The average fiber diameter can be adjusted by the above-mentioned single hole discharge amount, air pressure, spinneret temperature and the like.

Further, in order to secure the moldability of the nonwoven fabric for three-dimensional molding, it is necessary to control the bonding condition of the fibers in the web. Therefore, in order to manufacture the nonwoven fabric for three-dimensional molding of the present invention, it is necessary to cool the spun fiber stream. By doing this, the level of fiber fusion that occurs until the fiber stream is collected by the web molding machine is controlled, an appropriate web strength is secured, and when stress is applied during thermoforming. The fibers are appropriately deviated at a low stress, and the non-woven fabric is allowed to expand without breaking, which leads to improvement in molding processability. It is also possible to prevent the formation of the non-woven fabric from being deteriorated by fusion of the fibers before the fiber stream is collected by the molding machine, and as a result, the concealing property to be described later is deteriorated.
Regarding the cooling level, the temperature at a point 10 cm downstream from the nozzle in the center of the line CD direction and 5 cm away from the fiber discharge surface of the nozzle in the fiber flow direction (hereinafter, referred to as “temperature near fiber flow” in the present invention). Is sometimes referred to as ".") To 10 to 40 ° C. If the temperature in the vicinity of the fiber flow is less than 10 ° C., the degree of fusion of the fibers becomes too small, which causes a problem in securing the morphological stability of the nonwoven fabric. On the other hand, when the temperature exceeds 40 ° C., the degree of fusion of the fibers becomes too strong, and the web is broken without being properly stretched during the molding process. As a method for ensuring an appropriate temperature in this manner, a known method can be used, and the melt blowing apparatus itself is operated in an environment in which the temperature near the fiber flow is adjusted to 10 to 40 ° C. However, it is also possible to use a method in which cold air whose temperature is controlled as so-called secondary air is blown onto the fiber stream.

The nonwoven fabric for three-dimensional molding of the present invention has excellent heat resistance because it hardly crystallizes even when heated because the fibers constituting the nonwoven fabric are appropriately crystallized. Particularly, in the present invention, the dry heat area shrinkage ratio when the free heat treatment is performed for 2 minutes in the hot air of 120 ° C. is preferably 10% or less, and more preferably 5% or less. Similarly, the dry heat area shrinkage rate when heat-treated in hot air at 200 ° C. is preferably 10% or less, more preferably 5% or less.

Further, the three-dimensional molding nonwoven fabric of the present invention is also characterized in that it exhibits excellent thermoformability. Even when it is exposed to a high temperature, the polymer does not start flowing and the fiber form is formed. The merit is to keep it. In the nonwoven fabric for three-dimensional molding of the present invention, the flow initiation temperature of the mixed polymer constituting the nonwoven fabric for three-dimensional molding is 210 ° C, preferably 240 ° C or higher, and particularly preferably 2
It is 50 to 400 ° C. As described above, the nonwoven fabric for three-dimensional molding of the present invention has an excellent dry heat area shrinkage ratio and a high flow initiation temperature, and thus can be sufficiently thermoformed even at a high temperature of 200 ° C. or higher.

The non-woven fabric for three-dimensional molding of the present invention has an elongation in at least one direction of 50% or more and a 10% elongation modulus per unit weight of 0 in order to obtain better molding followability during thermoforming. 0.5 N / 5 cm / g / m
It is preferably ² or less. When the 10% elongation modulus per unit weight exceeds 0.5 N / 5 cm / g / m ² ,
Since the non-woven fabric is not flexible, when it is used for molding in a complicated shape, it may not be able to follow the shape to be molded firmly and the shape may not be sufficiently reproduced.
Further, if this value approaches 0 without limit, it may cause a problem in handleability during processing.
It is preferably / 5 cm / g / m ² . On the other hand, when the breaking elongation is less than 50%, the deep drawn portion may float or break, so that it is preferably 70% or more.

Furthermore, it is also an important factor that the nonwoven fabric for three-dimensional molding of the present invention has excellent uniformity and concealing property. Especially when used as a surface material, if the color of the base material located on the back side is different, if the concealing property of the non-woven fabric as the surface material is low, the base material etc. can be seen through the surface material and In some cases, it may result in a molded product that does not look good. The light transmittance can be used as a measure of the hiding property, and in the present invention, the light transmittance is preferably 50% or less, and more preferably 30% or less.

The three-dimensional molding non-woven fabric of the present invention can be given a design on the surface by printing a picture or a photograph by printing, etc. by utilizing the denseness of the ultrafine fibers. Also, if necessary, by kneading the raw materials and post-processing,
Various treatments such as coloring, flame retardancy, water repellency, and antifouling property may be performed.

The nonwoven fabric for three-dimensional molding of the present invention can be molded as a surface material as it is, but in the case where higher strength is required or in order to suppress fuzz and the like, morphological stabilization is performed by embossing or the like. You can measure. In this case, the embossing temperature is preferably 80 ° C to 150 ° C in order to secure the stretchability of the nonwoven fabric. When processed at a temperature of higher than 150 ° C., the fusion between the fibers becomes severe and the extensibility during the molding process does not develop, so that sufficient moldability may not be ensured. Further, at 80 ° C. or lower, since fiber adhesion does not occur so much,
Even if processed, the effect may not be obtained simply by damaging the nonwoven fabric.

The non-woven fabric for three-dimensional molding of the present invention can be preferably used as a surface material of a sound absorbing material. As an example, the three-dimensional molding non-woven fabric of the present invention can be manufactured by being integrated by pressure heating molding while being placed on a base material made of felt containing glass fibers and heat-fusible polyester fibers, for example. it can. At this time, if the heat resistance of the nonwoven fabric is low, the polymer melts due to the heat during molding and processing becomes impossible, or the fiber becomes brittle due to the heat during molding, and it cannot follow deformation and breaks. Resulting in.
Further, if the non-woven fabric has a low mold-following property, it may not follow the shape such as when the molding is very deep and wrinkles may occur, or the corners of deep drawing may be broken. On the other hand, if the non-woven fabric has sufficient strength, breakage can be avoided, but there is a problem that the corners are lifted or the entire thickness is reduced. This problem is a phenomenon which, especially in the case of a sound-absorbing material, a reduction in thickness leads to a reduction in the overall sound-absorbing performance, and it is necessary to avoid it as much as possible.

Therefore, by using the nonwoven fabric for three-dimensional molding of the present invention, it is possible to obtain a sound-absorbing material having excellent mold-following ability even in three-dimensional molding, especially in deep-drawing molding. The sound-absorbing material using the non-woven fabric for use exhibits extremely excellent sound-absorbing performance compared to the base material used alone. This is due to the fact that the fibers used for the surface material are ultrafine fibers, which improves the sound absorption performance,
It is presumed that this nonwoven fabric is able to maintain the original performance of the base material by ensuring the thickness of the base material by appropriately stretching during the molding process.

When the nonwoven fabric for three-dimensional molding of the present invention is used as a sound absorbing material, in order to further improve its workability,
A thermal adhesive layer may be provided on one side. As the heat adhesive layer,
There is no particular limitation, but the hot melt binder layer may be directly formed at a level that does not deteriorate the performance of the surface layer, or a composite in which a heat adhesive sheet is separately prepared and laminated with a non-woven fabric is used, or a molding process is performed. Sometimes, a method of laminating and integrating the three members is possible. The heat-adhesive sheet is preferably a flexible sheet that does not impair the extensibility of the ultrafine fibers, and it is particularly preferable to use a sheet such as a nonwoven fabric or a film made of a flexible thermoplastic elastomer or polyethylene. . Examples of the thermoplastic elastomer include an olefin elastomer composed of an ethylene-α-olefin copolymer, a polystyrene-polyethylenebutylene-polystyrene triblock copolymer hydrogenated polymer (SEBS), or a polystyrene-polyethylenepropylene-polystyrene triblock copolymer. Styrenic elastomers such as polymer hydrogenated polymers (SEPS) are useful. Further, as a method for producing the heat-adhesive sheet,
The use of the melt blow method is useful because the adhesive layer can be manufactured without separately preparing a hot melt machine or a film manufacturing apparatus.

These heat-adhesive layers may be formed by directly melt-blowing the obtained non-woven fabric, or may be formed into a non-woven fabric by itself and then laminated and composited by heat embossing, ultrasonic wave or the like. . Even when the heat-adhesive layer is combined, it is preferable to have the same 10% elongation modulus and elongation as in the case of using it alone in order to secure the molding followability.

Since the nonwoven fabric for three-dimensional molding of the present invention has excellent heat resistance and molding processability, it can be used not only for the above-mentioned sound absorbing material but also for daily use such as molded products and toys.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Each physical property value in this example was measured by the following methods.

1. Intrinsic viscosity of PET: dissolved in a mixed solvent of phenol / tetrachloroethane = 1/1, and the temperature was 30 ° C. using a capillary viscometer.
Then, the intrinsic viscosity [η] was obtained by the equation 1.

[Equation 1]

2. Average fiber diameter Scanning electron microscope (SEM) was used to take a photograph of the surface of the non-woven fabric magnified 1000 times. Two diagonal lines were drawn on this photograph, and the thickness of the fiber intersecting this diagonal line was converted to magnification. The value obtained was used. And the average value of 100 of these fibers was defined as the average fiber diameter. However, fibers in which two or more fibers are fused in a bundle or fibers having an abnormal shape cannot be measured because the thickness of each fiber cannot be measured, and therefore, they were excluded from the measurement targets.

3. Polymer flow start temperature It was measured using a viewer-type trace melting point measuring device (MP-500V) manufactured by Yanaco Instruments Development Laboratory. A slide glass on which the sample is placed is placed on the sample table, the sample table is heated at a temperature rising rate of 2 ° C./min, and the sample is visually observed with a magnifying glass provided, and the sample starts melting and flowing. The temperature was taken as the polymer flow start temperature.

4. Unit weight / thickness Measured according to JIS L1906 "General long-fiber nonwoven fabric test method".

5. High elongation / 10% elongation modulus Measured according to JIS L1906 "General long-fiber nonwoven fabric test method". Also, from the measurement chart at this time,
Read the stress at the time of elongation of 10% and set this value to 10%.
The extension modulus was used. The strength and elongation and the 10% elongation modulus were measured in the MD and CD directions of the nonwoven fabric.

6. Air permeability Measured in accordance with the Frazier type method of JIS L1906 "General long-fiber nonwoven fabric test method".

7. "Photoreflector Blood" manufactured by Toshiba Corporation as a light source of light transmittance
(100V, 300W) was used, the illuminance was measured using "Lux-meter ANA-315" manufactured by Tokyo Koden Co., Ltd., and the light transmittance was measured by the following formula. Light transmittance (%) = (illuminance when holding sample) / (blank illuminance) x 100

8. Sound absorption coefficient According to JIS A-1405, the sound absorption coefficient by the vertical incidence method was determined. Values of 1000 Hz and 2000 Hz were obtained as typical values.

9. Melt index PP: According to JIS K 6758; 230 ° C, 2.1
6 kg load. PE: According to JIS K 6760; 190 ° C, 2.1
6 kg load.

Example 1 95% by mass of PET having an intrinsic viscosity of 0.62 and 5% by mass of polypropylene (melt index: 200) were blended and heated and melted by an extruder, and then an orifice of 0.3 mmφ was 301 holes, 1 mm The fibers are discharged from a melt-blowing nozzle with a die width of 300 mm arranged in a row at a pitch, and heated air is jetted from an air slit with a slit width of 1 mm to capture the fine fibers on a wire mesh belt conveyor running 30 cm below. The meltblown nonwoven fabric was collected. Then, using an embossing device with a crimping area ratio of 10% to stabilize the shape, a temperature of 110 ° C. and a linear pressure of 35 kg / c.
m at a speed of 5 m / min to obtain a nonwoven fabric for three-dimensional molding.
As a result of measuring the flow starting temperature of the obtained nonwoven fabric for three-dimensional molding, it was 258 ° C. The results are shown in Table 1.

Nonwoven fabrics for three-dimensional molding were obtained in the same manner as in Example 1 except that the mixing ratio of PP in Examples 2 and 3 was changed to the ratio shown in Table 1. The flow starting temperature of these three-dimensional molding nonwoven fabrics is 25
It was 6 ° C. (Table 1)

Example 4 Instead of PP, LLDPE (melt index: 2)
A nonwoven fabric for three-dimensional molding was obtained in the same manner as in Example 2 except that 0) was used. The flow starting temperature of the obtained nonwoven fabric for three-dimensional molding was 250 ° C. (Table 1)

Comparative Example 1 A nonwoven fabric for three-dimensional molding was obtained in the same manner as in Example 1 except that only PET was used. The flow starting temperature of the obtained nonwoven fabric for three-dimensional molding was 260 ° C. (Table 1)

Comparative Example 2 A three-dimensional molding nonwoven fabric was obtained in the same manner as in Example 2 except that PBT having an intrinsic viscosity of 0.7 was used instead of PP. The flow starting temperature of the obtained nonwoven fabric for three-dimensional molding was 260 ° C. (Table 1)

Comparative Example 3 An attempt was made to obtain a nonwoven fabric for three-dimensional molding in the same manner as in Example 1 except that the mixing ratio of PET and PP was changed to 60/40. It was not possible to obtain a durable non-woven fabric for three-dimensional molding. (Table 1)

[0047]

[Table 1]

Examples 5-8, Comparative Examples 4-6 Sound absorbing material thermoforming processing test As a sound absorbing material base material, felt composed of 70% of regular polyester fiber of 1.5 dtex and 30% of modified polyester fiber of 4 dtex (basis weight: 600 g / M ² , thickness 1
5 mm) was prepared, and the nonwoven fabrics for three-dimensional molding obtained in the above Examples 1 to 4 and Comparative Examples 1 and 2 were placed on the respective surfaces to be integrally molded. The molding state at this time was visually observed, and the thickness after molding was measured with a caliper. The results are shown in Table 2.
Shown in. Molding conditions Molding shape: length 10 cm × width 10 cm × depth 10 mm box mold molding temperature, time: 200 ° C × 60 seconds

[0049]

[Table 2]

Sound Absorption Rate Test Of the molded products obtained in the above test, the molded product of Example 6,
The sound absorption coefficient was measured for a molded body molded using a PET spunbonded non-woven fabric having a basis weight of 20 g / m ² as a surface material and three samples of only polyester felt (unmolded product) as a reference example. The results are shown in Table 3.

[0051]

[Table 3]

From these results, it was not possible to obtain a sound absorbing material due to heat shrinkage and embrittlement of the nonwoven fabric when the nonwoven fabric for three-dimensional molding of Comparative Examples 1 and 2 was molded. Further, in the sound absorbing material of Comparative Example 6, the base material was crushed during the molding process, and the thickness after molding became thin.
Perhaps because of this, the sound absorption performance was also slightly lower than that of the mother alone. On the other hand, the sound absorbing material of Example 6 exhibited an excellent sound absorption coefficient.

[0053]

Industrial Applicability According to the present invention, it is possible to obtain a nonwoven fabric for three-dimensional molding which has excellent heat resistance and good form-following property even for complicated deep drawing. Further, even in a sound absorbing material having a complicated shape, by using the nonwoven fabric for three-dimensional molding of the present invention, a sound absorbing material having excellent sound absorbing performance can be obtained.

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Claims (5)

[Claims] 1. Polyethylene terephthalate 75 to 98
A non-woven fabric for three-dimensional molding comprising at least one component of a fiber made of a mixed polymer of 25 wt% to 25 wt% of a polyolefin-based polymer, characterized in that the non-woven fabric for three-dimensional molding satisfies the following 1) to 3). Non-woven fabric for three-dimensional molding. 1) The average fiber diameter is 10 μm or less, 2) the flow initiation temperature of the mixed polymer is 210 ° C. or higher, and 3) the dry heat area shrinkage ratio at 120 ° C. is 10% or less. 2. The composition according to claim 1, which has an elongation of 50% or more in at least one direction and a 10% elongation% modulus per unit weight in that direction of 0.5 N / 5 cm / g / m ² or less. Non-woven fabric for three-dimensional molding. 3. The three-dimensional molding non-woven fabric according to claim 1, which has a light transmittance of 50% or less. 4. The dry heat area shrinkage ratio at 200 ° C. is 10.
% Or less, The nonwoven fabric for three-dimensional molding according to any one of claims 1 to 3. 5. A sound absorbing material comprising the nonwoven fabric for three-dimensional molding according to any one of claims 1 to 4 as a surface material.