JP2749330B2 - High modulus needle punched nonwoven fabric and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high modulus needle punched nonwoven fabric used for industrial materials and interiors, and a method for producing the same.

(Prior Art) Conventionally, in order to produce a long-fiber needle punched nonwoven fabric, a long fiber obtained by melt-spinning a thermoplastic polymer is drawn by air soccer, and then deposited on a conveyor net to form a web. The web is heated and pressed by a hot press roll, for example, a hot roll composed of an embossing roll and a flat roll or a pair of embossing rolls, and then needling is performed. However, in the above-mentioned conventional method, the fibers constituting the web are not firmly heat-fused, and it is sufficient that the web is pressed to such an extent that its form is maintained until the needling step. Therefore, it is necessary to keep the thermal pressure welding before the needling to the extent that the temporary pressure welding is performed as weakly as possible in order to smoothly perform the subsequent needling process. However, in the above manufacturing method, although the needling process can be performed smoothly, it was difficult to obtain a high modulus needle punched nonwoven fabric. It has become

As a method for obtaining this high modulus nonwoven fabric,
The technology is disclosed in JP-A-133583 and JP-B-60-25543.

For example, the former method is a method of needling one side of a nonwoven web, heat setting, and then needling the other side, suppressing damage to the fiber due to needling, and improving the entanglement of the fiber. Thereby, a high modulus nonwoven fabric can be obtained. However, since the needling is performed on both sides, there is a disadvantage that the process is complicated and the cost is increased. Next, in the latter method, the entanglement of the fibers is improved by applying an oil agent before needling to reduce the piercing resistance of the needle and increasing the needle density, and a high modulus nonwoven fabric is obtained. . However, there is a drawback that the needle density is limited, the productivity is negative, and it is difficult to obtain an efficient entangled nonwoven fabric due to slippage between fibers. As another method, it is possible to improve the modulus of the nonwoven fabric by increasing the thermal pressure welding rate, but the texture becomes coarse and hard, which is unsuitable for the field where flexibility is required. Was.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems, and does not reduce the productivity of the nonwoven fabric, has no trouble such as needle breakage in the needling process, and is flexible in the feeling. It is an object of the present invention to provide a high modulus needle punched nonwoven fabric which maintains the properties.

(Means for Solving the Problems) The present inventors have made intensive studies to obtain a high-modulus nonwoven fabric that can be used for industrial materials, interior use, and the like, and have reached the present invention.

That is, the present invention is a non-woven fabric made of thermoplastic synthetic long fibers having a single yarn fineness of 1.5 to 15 denier, and the non-woven fabric is partially heat-welded at a heat-welded area ratio of 10 to 40%, Needle density is 20 to 80 times / cm ² , long fibers are entangled by needling, impregnated with acrylic resin, and stress at 3% elongation is more than 20kg / 5cm in vertical length.
The gist of the invention is a high modulus needle punched nonwoven fabric of 15 kg / 5 cm or more. The present invention also provides a method of producing a nonwoven fabric by subjecting a web composed of thermoplastic synthetic filaments to partial heat pressing and then performing needle punching to obtain a unit yarn fineness.
A web made of 1.5 to 15 denier thermoplastic synthetic long fiber is heat-welded with an embossing roll so that the heat-welded area ratio becomes 10 to 40% at a temperature of 10 to 100 ° C below the melting point of the synthetic long fiber, Next, a needling is performed at a needle density of 20 to 80 times / cm ² , an acrylic resin is impregnated in the needled needle, and the needle is dried, followed by drying.

As the thermoplastic synthetic long fibers used in the present invention, polyethylene terephthalate, polyesters such as polybutylene terephthalate, polyethylene, polyolefins such as polypropylene, nylon 6, and polyamide-based polymers such as nylon 66; Also included are those comprising blends of these polymers. As the form of the long fiber, in addition to the long fiber composed of 100%, any of a bonded composite long fiber and a core-sheath composite long fiber composed of these polymers can be used.

Next, it is necessary that the single denier of the thermoplastic synthetic long fiber is in the range of 1.5 to 15 denier. When the single-filament fineness is less than 1.5 denier, when heat-welded, heat is transferred to the center of the long fiber, so that the non-woven fabric becomes plastic due to the heat-welding, and the feel becomes coarse and hard. In addition, in the needling step, since the flexibility between the long fibers is poor, the long fibers are frequently cut, and a high modulus nonwoven fabric cannot be obtained. On the other hand, when the single-fiber fineness exceeds 15 denier, the pressure contact between the long fibers is small, and the pressure-contact portion is easily detached in the needling process, so that the modulus of the obtained nonwoven fabric becomes low. .

In performing the heat-pressing, the heat-pressing is performed by a pair of rolls including an embossing roll and a flat roll or two embossing rolls. The pressing temperature is in the temperature range of 10 to 100 ° C. below the melting point of the long fiber used, and the pressing area ratio needs to be in the range of 10 to 40%.

In the case where the long fibers constituting the nonwoven fabric are conjugate long fibers composed of two kinds of polymers, the heat welding temperature is based on a polymer having a low melting point. When the pressing temperature is higher than the melting point of the long fiber and higher than the melting point of the long fiber by more than 10 ° C., the pressure junction becomes strong.However, when the nonwoven fabric becomes plastic due to the softening flow of the polymer and the needle penetrates at the time of needling, the length becomes longer. Fibers are cut or only needle holes are formed into a nonwoven fabric, and only a nonwoven fabric with poor entanglement is obtained. For this reason, the feeling is soft and a high modulus nonwoven fabric cannot be obtained. On the other hand, when the temperature is lower than the melting point of the long fiber and lower than 100 ° C., the pressure contact is weak, and at the time of needling, when the needle penetrates, the pressure contact portion easily comes off, and only a nonwoven fabric having a low modulus can be obtained.

Here, the pressed area ratio is defined as the ratio of the area of the pressed portion to the entire area of the nonwoven fabric sheet. When the pressed area ratio is less than 10%, the number of bonding points between long fibers is small. A high modulus nonwoven fabric cannot be obtained. On the other hand, if the press contact area ratio exceeds 40%, the number of press contacts between the long fibers becomes too large, the nonwoven fabric becomes plastic, and the needles penetrate during needling, and the long fibers are cut. Further, the probability of breakage of the needle is increased, and a high-modulus nonwoven fabric cannot be manufactured from the viewpoint of operation.

Next, as the range of needle density in needling,
It is necessary to be 20 to 80 times / cm ² . If the needle density is less than 20 times / cm ² , the degree of entanglement of long fibers is small, and a high modulus needle punched nonwoven fabric cannot be obtained. On the other hand, when it exceeds 80 times / cm ² , the entanglement of the long fibers in the non-welded portion is good,
Often, the heat-welded part is broken by penetration of the needle. This means that in the press-contact portion, the long fibers have little mobility and the long fibers that cannot follow the movement of the needles are cut, so that a high modulus needle punched nonwoven fabric cannot be obtained.

The needle-punched nonwoven fabric of the present invention numerically limits the single-filament fineness of the long fibers constituting the nonwoven fabric and the temperature range at the time of hot-pressing, and further examines the hot-pressing area ratio and the number of needle punches that contribute to the improvement of the modulus. As a result, a well-balanced nonwoven fabric was obtained for the first time.

(Function) The needle-punched nonwoven fabric of the present invention has a portion in which the mobility of long fibers constituting the nonwoven fabric is suppressed by thermal pressure welding;
The portion in which the entangled portion of the constituent long fibers is improved by needling is mixed in a well-balanced manner.
Therefore, when the needle penetrates by needling,
There is no trouble such as cutting of the long fiber or breakage of the needle at the heat-welded portion, the operability is good, and the effect of entanglement of the long fiber is improved. Furthermore, the heat-pressed part is 10 ~
By occupying 40% of the constituent long fibers, the portion where the press-contact portion is restricted contributes to the improvement of the modulus. As described above, since the needle-punched nonwoven fabric of the present invention contributes to the improvement of the modulus at both the heat-pressed portion and the entangled portion of the long fiber, a high-modulus nonwoven fabric having flexibility can be obtained. I guess.

(Examples) Hereinafter, the present invention will be described specifically with reference to examples. In addition, the evaluation method of the nonwoven fabric performed in the Example is collectively shown below.

(1) Tensile strength Using a constant speed elongation type tester Toyo Baldwin Co., Ltd. Tensilon UTM-4-100 type, gripping a test piece of 5 cm width and 30 cm length, spacing 20 cm, tensile speed 20 cm / min, n = It was determined from the average value of 10.

(2) Stress at 3% Elongation Measurement was performed according to the above tensile strength measurement, and the stress at 3% elongation was determined from the SS curve.

(3) Evaluation of the appearance of the sheet surface The appearance of the needle punched nonwoven fabric was evaluated by visual judgment. The evaluation criteria are as follows.

…: Small needle hole and less fuzz ×: Large needle hole and conspicuous irregularities on the back surface, or any of them Example 1 Melting point 260 ° C, intrinsic viscosity [phenol / ethane tetrachloride Mixed solvent, 1: 1 (weight ratio) measured at 20 ° C.] [η] = 0.68 polyethylene terephthalate was discharged from the spinneret at a melting temperature of 285 ° C. using a spinneret having a pore diameter of 0.35 mm and 160 holes,
Suction was performed by air soccer at a spinning speed of 4500 m / min, and the drawn long fibers were collected on a wire mesh net.

The single-filament denier 3-denier polyester long fiber web thus obtained was heated at a temperature of the hot pressing roll 210 by using a hot pressing apparatus comprising a hot pressing roll and a flat roll.
The embossing pattern was a hot-welding process using a rod-shaped dashed pattern parallel to the sheet advancing direction to obtain a web having a basis weight of 140 g / m ² .

Next, the web was needled at a needle density of 40 times / cm ² with a needle punching machine (needle; PPD-1♯40 manufactured by Organ Co., Ltd.) to obtain a nonwoven fabric. The obtained non-woven fabric was coated with an acrylic resin (product of Dainippon Ink and Chemicals, Inc., trade name: Boncoat JH-56, emulsion type) with a solid content of 12
%, And then dried. The physical properties and sensory tests of the obtained product were performed, and the results are shown in Table 1.

Examples 2 to 7, Comparative Examples 1 to 3 Single yarn denier of polyethylene terephthalate long fiber,
A needle-punched nonwoven fabric was manufactured in the same manner as in Example 1 except that the hot pressing area ratio and the needle density in needling were changed. Table 1 shows the obtained results.

Example 8 Nylon 6 having a melting point of 220 ° C. and a relative viscosity of 2.5 (using 98% sulfuric acid, polymer concentration of 1%, and measured at 25 ° C.) was prepared from a spinneret having a hole diameter of 0.35 mm and 160 holes at a melting temperature of 260 ° C. It was discharged and sucked by air soccer at a spinning speed of 4500 m / min, and the drawn long fibers were collected on a wire mesh net.

Except for changing the hot pressing roll temperature to 170 ° C. on the thus obtained single yarn denier 1.5 denier web, all other conditions were subjected to the hot pressing process according to Example 1 to obtain a basis weight 18.
The web was 0 g / m ² . Next, the web was subjected to needling treatment and resin processing according to Example 1. The physical properties and sensory tests of the obtained product were performed, and the results are shown in Table 1.

As is clear from Table 1, the nonwoven fabric of the present invention had high tensile strength, high stress at 3% elongation, and good sheet surface quality.

(Effects of the Invention) According to the present invention, as a form of long fibers constituting the nonwoven fabric, the entanglement of the long fibers by the hot-pressed portion and the needling are mixed in a well-balanced manner, so that the sheet has high modulus and good sheet appearance quality. A needle-punched nonwoven fabric can be obtained.

Claims (2)

(57) [Claims] 1. A non-woven fabric comprising thermoplastic synthetic filaments having a single fiber fineness of 1.5 to 15 denier, wherein said non-woven fabric is partially heat-welded at a heat-welding area ratio of 10 to 40%,
Needle density is 20 to 80 times / cm ² , long fibers are entangled by needling, impregnated with acrylic resin, and stress at 3% elongation is more than 20kg / 5cm in vertical length, 15kg / 5cm in width A high modulus needle punched nonwoven fabric characterized by the above. 2. A web made of thermoplastic synthetic filaments having a single yarn fineness of 1.5 to 15 denier when a web made of thermoplastic synthetic filaments is partially hot-pressed and then subjected to needle punching to produce a nonwoven fabric. Below the melting point of the synthetic long fiber 10
Heat-pressing is performed with embossing rolls so that the area ratio of hot-pressing is 10 to 40% at a temperature of ~ 100 ° C.
A method for producing a high modulus needle punched nonwoven fabric, which comprises needling at 80 times / cm ² , impregnating the resin with an acrylic resin, and then drying.