Laminated long-fiber nonwoven fabric, and bag-like object using the same

Abstract

Provided is a long-fiber nonwoven fabric laminate, wherein: at least two long-fiber nonwoven fabrics are laminated; a high-shrinkage fiber, of which a shrinkage rate for three minutes at 135°C is at least 15%, is present between one or more layers of the long-fiber nonwoven fabric laminate; and the area shrinkage rate of the laminate is at least 30%.

Description

[Technical Field]

[0001] This invention relates to a laminate of long-fiber nonwoven fabric with excellent shrinkage properties, and a bag-like object using the same. [Background technology]

[0002] In nonwoven fabrics, there are techniques for shrinking them by heating. For example, Patent Document 1 discloses a technique that allows shrinkage at low temperatures by blending amorphous polyester, thus reducing the thermal energy required for the shrinkage process and contributing to energy saving. Patent Document 2 also discloses a highly shrinkable nonwoven fabric containing short fibers of isophthalic acid copolymerized polyethylene terephthalate. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. "JP 2014-240531" [Patent Document 2] Japanese Patent Publication No. "JP 2003-336151" [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, the nonwoven fabric described in Patent Document 1 is a blend of polyethylene terephthalate rather than a single material, making it difficult to recycle. Furthermore, Patent Document 2 is a short-fiber nonwoven fabric, which is inferior in strength to a long-fiber nonwoven fabric.

[0005] This invention was made against the backdrop of the problems of the prior art described above, and its purpose is to provide a long-fiber nonwoven fabric laminate with high shrinkability and excellent mechanical strength. [Means for solving the problem]

[0006] As a result of intensive studies aimed at solving the above problems, the present inventors have finally completed the present invention. That is, the present invention is as described below. 1. A long-fiber nonwoven fabric laminate formed by laminating at least two long-fiber nonwoven fabrics, wherein high-shrinkage fibers having a shrinkage rate of 15% or more when treated at 135°C for 3 minutes are present in at least one interlayer of the long-fiber nonwoven fabric laminate, and the area shrinkage rate is 30% or more, the long-fiber nonwoven fabric laminate being characterized by that. 2. The long-fiber nonwoven fabric laminate according to the above 1, which has a basis weight of 60 to 200 g / m 2 , and 50 to 350 of the high-shrinkage fibers are present per m between the interlayers 2 , the long-fiber nonwoven fabric laminate being characterized by that. 3. The long-fiber nonwoven fabric laminate according to the above 1 or 2, wherein the high-shrinkage fibers are present substantially parallel to each other between the interlayers, the long-fiber nonwoven fabric laminate being characterized by that. 4. The long-fiber nonwoven fabric laminate according to any one of the above 1 to 3, wherein the fineness of the high-shrinkage fibers is 22 to 2340 dtex, the long-fiber nonwoven fabric laminate being characterized by that. 5. The long-fiber nonwoven fabric laminate according to any one of the above 1 to 4, wherein the high-shrinkage fibers are polyethylene fibers, the long-fiber nonwoven fabric laminate being characterized by that. 6. The long-fiber nonwoven fabric laminate according to any one of the above 1 to 5, wherein the transverse shrinkage rate of the long-fiber nonwoven fabric is 15% or more, the long-fiber nonwoven fabric laminate being characterized by that. 7. The long-fiber nonwoven fabric laminate according to any one of the above 1 to 6, wherein the shrinkage stress of the long-fiber nonwoven fabric is 20 N or more, the long-fiber nonwoven fabric laminate being characterized by that. 8. The long-fiber nonwoven fabric laminate according to any one of the above 1 to 7, which is mechanically entangled, the long-fiber nonwoven fabric laminate being characterized by that. 9. A bag-shaped article using the long-fiber nonwoven fabric laminate according to any one of the above 1 to 8, the bag-shaped article having a joint portion where the long-fiber nonwoven fabrics are joined to each other by thermocompression bonding, the bag-shaped article being characterized by that. 10. The bag-shaped article according to the above 9, which is brought into close contact with the content placed inside the bag-shaped article by heat shrinkage, the bag-shaped article being characterized by that. 11. The bag-shaped article according to the above 9 or 10, wherein the joint strength at the joint portion is 1 / 3 or less of the base fabric strength of the long-fiber nonwoven fabric, the bag-shaped article being characterized by that. Effects of the Invention

[0007] According to the present invention, a long-fiber nonwoven fabric laminate excellent in shrinkability and a bag-like article can be obtained. In addition, the long-fiber nonwoven fabric laminate and the bag-like article of the present invention are excellent in mechanical strength properties, lightweight, and excellent in handleability.

Mode for Carrying Out the Invention

[0008] Hereinafter, the present invention will be specifically described, but the present invention is not limited to the following, and it is also possible to implement the present invention with appropriate modifications within the range that can conform to the gist of the preceding and following descriptions, all of which are included in the technical scope of the present invention. [Long-fiber nonwoven fabric] The long-fiber nonwoven fabric used in the present invention will be described. The resin used for the long-fiber nonwoven fabric is not particularly limited, and among them, polyester is preferred, and polyethylene terephthalate (PET), which is a general-purpose thermoplastic resin and inexpensive, is particularly preferred. Other homopolyesters such as polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN), polycyclohexanedimethylene terephthalate (PCHT), and polytrimethylene terephthalate (PTT) can be exemplified. In the present invention, a long-fiber nonwoven fabric made of PET is used as the base long-fiber nonwoven fabric. This is because PET is excellent in properties such as toughness and heat resistance. In addition, as long as the content is less than 1% by mass, polyesters other than PET may be blended. The intrinsic viscosity of PET is not particularly limited, but is preferably 0.63 dl / g or more. It may also contain commonly used additives such as paints, pigments, matting agents, antistatic agents, flame retardants, and reinforcing particles.

[0009] A method for obtaining a long-fiber nonwoven fabric will be described. The production method of the long-fiber nonwoven fabric is not particularly limited, but from the viewpoint of easily obtaining productivity and mechanical strength properties as the long-fiber nonwoven fabric, it is preferable to produce it by the spunbond method. In order to obtain a long-fiber nonwoven fabric with a high shrinkage rate by the same method, a method is used in which the resin used is fiberized at a spinning speed lower than the condition for obtaining stable filaments by oriented crystallization, and then formed into a sheet. The spinning speed needs to be appropriately changed depending on the resin used, and when PET is usually used, the spinning speed is preferably 2000 to 3500 m / min, more preferably 2000 to 3000 m / min. The average fiber diameter of the long fibers (single fibers) constituting the long-fiber nonwoven fabric is preferably about 1 to 20 dtex, more preferably about 2 to 15 dtex. In addition, the basis weight of the long-fiber nonwoven fabric can be set in consideration of the mechanical strength properties required for the final product, but in order to obtain the stress for shrinking by heat treatment, it is 55 g / m 2 or more, which is preferable. In consideration of the process passability of the needle punching step after obtaining the long-fiber nonwoven fabric, it is preferable that the long-fiber nonwoven fabric is crimped to such an extent that conveyability can be obtained. When the average fiber diameter and the basis weight are within the above ranges, various properties such as tenacity, processability, and flexibility can be made excellent in a well-balanced manner.

[0010] The birefringence (Δn) of the fibers constituting the long-fiber nonwoven fabric is 60×10 -3 or less, which is preferable. It is more preferably 40×10 -3 or less, and still more preferably 35×10 -3 or less. When the birefringence of the fibers exceeds 60×10 -3 , the polymer molecules are oriented and crystallized, so that shrinkage is inhibited, resulting in a low shrinkage rate. The birefringence can be controlled by the discharge conditions, cooling conditions, and drawing conditions during fiberization. When a particularly high shrinkage rate is required, the spinning speed is preferably 2000 to 3500 m / min, and it is more preferable to perform spinning at 2500 to 3000 m / min.

[0011] The specific gravity of the fibers constituting the long-fiber nonwoven fabric is preferably 1.330 to 1.340 g / cm 3 , and 1.335 to 1.340 g / cm 3This is more preferable. Within the above range, it is possible to achieve a good balance of each characteristic, such as strength, processability, and flexibility.

[0012] [Laminated long-fiber nonwoven fabric] Next, an example of the long-fiber nonwoven fabric laminate of the present invention and a method for producing the same will be described. First, high-shrinkage fibers are placed on top of the long-fiber nonwoven fabric, and then another long-fiber nonwoven fabric is placed on top of them, and the fibers are entangled by needle punching. The high-shrinkage fibers may be placed randomly, but it is preferable to place them parallel to the machine direction of the long-fiber nonwoven fabric. This arrangement makes it possible to particularly increase the shrinkage in the machine direction.

[0013] Polyethylene fibers are suitable as the high-shrinkage fibers to be placed between the two layers of long-fiber nonwoven fabric. For example, Tsunooga and IZANAS from Toyobo Co., Ltd., and Dyneema from DSM can be used. The polyethylene fibers can be selected within a range that maintains strength and shrinkage, and the fineness of the polyethylene fibers is preferably around 22 to 2340 dtex, with a single filament fineness of 7 dtex or less. If the single filament fineness of the polyethylene fibers exceeds 7 dtex, the fibers become too thick, and there is a risk of needle breakage during needle punching. The number of high-shrinkage fibers to be placed is 50 to 350 fibers / m 2 Preferably, 150-300 strands / m 2 This is more preferable. 50 strands / m 2 If the number is less than 350 strands / m, there is a risk of insufficient shrinkage. 2 If the amount exceeds a certain level, the confluence during needle punching will worsen, and there is a risk of detachment.

[0014] Laminated long-fiber nonwoven fabrics are composed of fibers with a high area shrinkage rate, resulting in low filament strength and making them susceptible to fiber breakage during needle punching. This can easily lead to problems such as reduced strength after needle punching. The number of penetrations and needle depth should be appropriately set depending on the type of needle used, the desired mechanical strength characteristics, and the fabric weight; there are no limitations.

[0015] The long-fiber nonwoven fabric laminate of the present invention can be easily formed into a bag-like object by joining them by heat compression. A bag-like object using the long-fiber nonwoven fabric laminate of the present invention is also within the scope of the present invention. The bag-like object of the present invention has a joint formed by joining long-fiber nonwoven fabrics together by heat compression. Preferably, the joint strength of the bag-like object of the present invention is one-third or less of the strength of the long-fiber nonwoven fabric. Within this range, the bag-like object can be easily opened from the joint if desired. Furthermore, the bag-like object can be made to adhere tightly to the contents placed inside by heat shrinkage. [Examples]

[0016] The present invention will be further described by the following examples, but these examples are not intended to limit the present invention, and any modifications or implementations that do not depart from the spirit of the invention are all included within the technical scope of the present invention. First, the method for characterization will be described.

[0017] <High shrinkage fiber shrinkage rate> The shrinkage rate of high-shrinkage fibers is measured in accordance with JIS L 1013 (2010) 8.18.2b), by cutting the filament to the sample size and applying heat at 135°C for 3 minutes.

[0018] <Nonwoven fabric shrinkage rate> In accordance with JIS L 1913 (2010) 6.10, the long-fiber nonwoven fabric is cut into 250 mm squares at any 10 locations, and marks indicating a length of 200 mm are made at 3 locations in both the warp and weft directions. The fabric is heat-treated in a constant-temperature dryer at 130°C for 3 minutes, and the shrinkage rate (in the weft direction) is determined from the dimensional change before and after heat treatment.

[0019] <Nonwoven fabric shrinkage stress> The shrinkage stress of the long-fiber nonwoven fabric was measured using a constant-speed elongation tensile testing machine (Tensilon, manufactured by Orientec) and the machine's constant-temperature chamber, under heat treatment at 130°C for 390 seconds. The average value of the obtained shrinkage stress (N) was defined as the nonwoven fabric shrinkage stress (N) for five 50 mm wide, 200 mm long sample pieces of the long-fiber nonwoven fabric, with a gripping interval of 100 mm. <Birefringence> For single fibers extracted from long-fiber nonwoven fabric, retardation and fiber diameter are read using a deflection microscope equipped with a Berec compensator, and the average value for n=5 is taken as the birefringence (Δn) of the fiber.

[0020] <Specific gravity> The specific gravity of the fibers is measured using a density gradient tube with n=4, and the average value is calculated.

[0021] <Ratio of dry heat surface shrinkage rates in the vertical and horizontal directions> In accordance with JIS L 1913 (2010) 6.10, the long-fiber nonwoven fabric is cut into 250 mm squares at 10 arbitrary locations, and marks indicating a length of 200 mm are made at 3 locations in both the warp and weft directions. The fabric is heat-treated in a constant-temperature dryer at 100°C for 3 minutes, and the ratio of the warp direction to the weft direction is determined from the dimensional change before and after heat treatment. <Inspector> The measurement will be taken in accordance with the method described in JIS L 1913 (2010), using a 20cm x 20cm area, and the mass per unit area will be measured.

[0022] <Area contraction rate> In accordance with JIS L 1913 (2010) 6.10, the entangled long-fiber nonwoven fabric laminate is cut into 250 mm squares at 10 arbitrary locations, and marks representing 200 mm in length are placed at 3 locations in both the warp and weft directions. The laminate is heat-treated in a constant-temperature dryer at 100°C for 3 minutes, and the area shrinkage rate is determined from the dimensional change before and after heat treatment. Comparative Example 1 is performed similarly using the entangled long-fiber nonwoven fabric.

[0023] <Base fabric strength> In accordance with JIS L 1913(2919) 6.3 Tensile strength and elongation (ISO method), five 50 mm wide, 200 mm long sample pieces of a long-fiber nonwoven fabric laminate (Comparative Example 1 is the long-fiber nonwoven fabric after entanglement treatment) were measured using a constant-speed elongation tensile testing machine (Tensilon, manufactured by Orientec) with a gripping distance of 100 mm and a tensile speed of 200 mm / min. The average value of the tensile strength obtained was defined as the bonding strength (N / 5cm).

[0024] <Joining strength> Two samples were cut from the entangled long-fiber nonwoven fabric laminate (Comparative Example 1 was the entangled long-fiber nonwoven fabric), and heat-sealed in the width direction at 268°C for 2 minutes using a heat sealer (Auto Sealer FA-450-5W series, manufactured by Fuji Impulse Co., Ltd.). The unfolded samples were then subjected to tensile strength and elongation (ISO method) according to JIS L-1913 6.3 using a constant-speed elongation tensile testing machine (Tensilon, manufactured by Orientec) and the same testing machine. The tensile strength was measured at 20 sample pieces, each 50 mm wide and 200 mm long, with a gripping interval of 100 mm and a tensile speed of 200 mm / min, and the average value of the obtained tensile strength was defined as the bonding strength (N / 5cm).

[0025] (Example 1) Polyester with an intrinsic viscosity of 0.63 dl / g and a polyethylene terephthalate component of 99% or more was used as the raw material for the long-fiber nonwoven fabric. The fibers were spun at a spindle with an orifice diameter of φ0.30 mm at a spinning temperature of 285°C, with a single-hole discharge rate of 1.74 g / min. While cooling with 20°C air at a wind speed of 0.75 m / sec from 120 mm directly below the spindle, the fibers were ejected at an ejector positioned 900 mm directly below the spindle at a rate of 0.85 kg / cm³. 2 Dry air was supplied at a certain pressure, the fibers were stretched in one stage, and the fiber bundles were spread and piled up on a conveyor net 1.0 m below, with the speed adjusted to ensure a random fiber arrangement. The single filament fineness was 6.0 dtex, the converted spinning speed was 2800 m / min, and Δn was 41 × 10⁻¹⁴. -3 , with a specific gravity of 1.338 g / cm³ 3 The ratio of dry heat area shrinkage in the vertical and horizontal directions is 1.01, and the basis weight is 55 g / m². 2 A long-fiber nonwoven fabric was obtained.

[0026] Next, embossing was performed at 60°C and a linear pressure of 30kN / m using an embossing roll with frustum-shaped protrusions arranged in a staggered pattern and a pressure application area ratio of 8%, which was installed in-line, to obtain a heat-sealed type long-fiber nonwoven fabric. Polyethylene fibers (Tsunooga 440dtex, manufactured by Toyobo Co., Ltd.) were added to the above heat-sealed type long-fiber nonwoven fabric at a rate of 300 fibers / m as high-shrinkage fibers. 2The fibers are arranged in the longitudinal direction, and the above-mentioned heat-sealable long-fiber nonwoven fabric is layered on top, with a needle density of 51 fibers / cm². 2 The threads were then entangled using needle punching with a needle depth of 12 mm (Organ FPD220), resulting in a basis weight of 120 g / m². 2 A laminate of long-fiber nonwoven fabric was obtained. Fluoroscopy confirmed that the highly shrinkable fibers were arranged in roughly parallel directions.

[0027] The above-mentioned long-fiber nonwoven fabric laminate was cut into pieces measuring 11 cm vertically and 5 cm horizontally, and the edges were heat-sealed 1 cm from the end to obtain a bag-like object with a joint. The entire surface of the heat-sealed portion was joined, forming a joint. Contents were placed inside the bag-like object, and it was heat-treated at 268°C for 2 minutes to obtain a heat-shrunk bag-like object. It was visually confirmed that the bag-like object and its contents were tightly adhered due to the heat shrinkage. Furthermore, the joint strength was evaluated by cutting both ends of the joint in the vertical direction of the bag-like object using the method described above.

[0028] (Example 2) Polyester with an intrinsic viscosity of 0.63 dl / g and a polyethylene terephthalate component of 99% or more was used as the raw material for the long-fiber nonwoven fabric. The fibers were spun at a spindle with an orifice diameter of φ0.30 mm at a spinning temperature of 285°C, with a single-hole discharge rate of 1.74 g / min. While cooling with 20°C air at a wind speed of 0.75 m / sec from 120 mm directly below the spindle, the fibers were ejected at an ejector positioned 900 mm directly below the spindle at a rate of 0.85 kg / cm³. 2 Dry air was supplied at a certain pressure, the fibers were stretched in one stage, and the fiber bundles were spread and piled up on a conveyor net 1.0 m below, with the speed adjusted to ensure a random fiber arrangement. The single filament fineness was 6.0 dtex, the converted spinning speed was 2800 m / min, and Δn was 41 × 10⁻¹⁴. -3 , with a specific gravity of 1.338 g / cm³ 3 A base weight of 45 g / m² with a ratio of dry heat shrinkage rates in the vertical and horizontal directions of 1.01. 2 A long-fiber nonwoven fabric was obtained.

[0029] Next, an embossing process was performed at 60°C and a linear pressure of 30kN / m using an embossing roll with frustum-shaped protrusions arranged in a staggered pattern and a pressure application area ratio of 8%, which was installed in-line, to obtain a heat-sealed type long-fiber nonwoven fabric. Polyethylene fibers (Tsunooga 440dtex, manufactured by Toyobo Co., Ltd.) were then added to the above heat-sealed type long-fiber nonwoven fabric at a rate of 300 fibers / m. 2 The sheets are arranged in the longitudinal direction, and the above-mentioned heat-sealable long-fiber nonwoven fabric is layered on top, with a needle density of 51 needles / cm². 2 Then, entanglement treatment was performed by needle punching with a needle depth of 12 mm (Organ FPD220), resulting in a basis weight of 100 g / m². 2 A long-fiber nonwoven fabric laminate was obtained.

[0030] The above-mentioned long-fiber nonwoven fabric laminate was cut into pieces measuring 11 cm vertically and 5 cm horizontally, and the edges were heat-sealed 1 cm from the end to obtain a bag-like object with a joint. The entire surface of the heat-sealed portion was joined, forming a joint. Contents were placed inside the bag-like object, and it was heat-treated at 268°C for 2 minutes to obtain a heat-shrunk bag-like object. It was visually confirmed that the bag-like object and its contents were tightly adhered due to the heat shrinkage. Furthermore, the joint strength was evaluated by cutting both ends of the joint in the vertical direction of the bag-like object using the method described above.

[0031] (Example 3) As the raw material for the long-fiber nonwoven fabric, polyester with an intrinsic viscosity of 0.63 dl / g and a polyethylene terephthalate component of 99% or more was used. The fibers were spun at a spindle with an orifice diameter of φ0.30 mm at a spinning temperature of 285°C, with a single-hole discharge rate of 1.74 g / min. The fibers were cooled with 20°C air at a wind speed of 0.75 m / sec from 120 mm directly below the spindle, and then ejected at a rate of 0.85 kg / cm³ to an ejector positioned 900 mm directly below the spindle. 2 Dry air was supplied at a certain pressure, the fibers were stretched in one stage, and the fiber bundles were spread and piled up on a conveyor net 1.0 m below, with the speed adjusted to ensure a random fiber arrangement. The single filament fineness was 6.0 dtex, the converted spinning speed was 2800 m / min, and Δn was 41 × 10⁻¹⁴. -3 , with a specific gravity of 1.338 g / cm³ 3 The ratio of dry heat shrinkage rates in the vertical and horizontal directions is 1.01, and the basis weight is 62 g / m². 2 A long-fiber nonwoven fabric was obtained.

[0032] Next, an embossing process was performed at 60°C and a linear pressure of 30kN / m using an embossing roll with frustum-shaped protrusions arranged in a staggered pattern and a pressure application area ratio of 8%, which was installed in-line, to obtain a heat-sealed type long-fiber nonwoven fabric. Polyethylene fibers (Tsunooga 440dtex, manufactured by Toyobo Co., Ltd.) were then added to the above heat-sealed type long-fiber nonwoven fabric at a rate of 300 fibers / m. 2 The sheets are arranged in the longitudinal direction, and the above-mentioned heat-sealable long-fiber nonwoven fabric is layered on top, with a needle density of 51 needles / cm². 2 The entanglement was treated by needle punching with a needle depth of 12 mm (Organ FPD220), resulting in a basis weight of 134 g / m². 2 A long-fiber nonwoven fabric laminate was obtained.

[0033] The above-mentioned long-fiber nonwoven fabric laminate was cut into pieces measuring 11 cm vertically and 5 cm horizontally, and the edges were heat-sealed 1 cm from the end to obtain a bag-like object with a joint. The entire surface of the heat-sealed portion was joined, forming a joint. Contents were placed inside the bag-like object, and it was heat-treated at 268°C for 2 minutes to obtain a heat-shrunk bag-like object. It was visually confirmed that the bag-like object and its contents were tightly adhered due to the heat shrinkage. Furthermore, the joint strength was evaluated by cutting both ends of the joint in the vertical direction of the bag-like object using the method described above.

[0034] (Comparative Example 1) As the raw material for the long-fiber nonwoven fabric, polyester with an intrinsic viscosity of 0.63 dl / g and a polyethylene terephthalate component of 99% or more was used. The fibers were spun at a spindle with an orifice diameter of φ0.30 mm at a spinning temperature of 285°C, with a single-hole discharge rate of 1.74 g / min. The fibers were cooled with 20°C air at a wind speed of 0.75 m / sec from 120 mm directly below the spindle, and then ejected at a rate of 0.85 kg / cm³ to an ejector positioned 900 mm directly below the spindle. 2 Dry air was supplied at a certain pressure, the fibers were stretched in one stage, and the fiber bundles were spread and piled up on a conveyor net 1.0 m below, with the speed adjusted to ensure a random fiber arrangement. The single filament fineness was 6.0 dtex, the converted spinning speed was 2800 m / min, and Δn was 41 × 10⁻¹⁴. -3 , with a specific gravity of 1.338 g / cm³ 3The ratio of dry heat shrinkage rates in the vertical and horizontal directions is 1.01, and the basis weight is 100g / m². 2 A long-fiber nonwoven fabric was obtained.

[0035] Next, an embossing process was performed at 60°C and a linear pressure of 30 kN / m using an embossing roll with frustum-shaped protrusions arranged in a staggered pattern and a pressure application area ratio of 8%, which was installed in-line, to obtain a heat-sealed type long-fiber nonwoven fabric. The above heat-sealed type nonwoven fabric was then processed with a needle density of 51 needles / cm². 2 Then, entanglement treatment was performed by needle punching with a needle depth of 12 mm (Organ FPD220), resulting in a basis weight of 100 g / m². 2 A nonwoven fabric made of long fibers that had been entangled was obtained.

[0036] The entangled long-fiber nonwoven fabric described above was cut into strips 11 cm long and 5 cm wide, and the edges were heat-sealed 1 cm from the end to obtain a bag-like object with a joint. The entire surface of the heat-sealed portion was joined, forming a joint. The contents were placed in the bag-like object and heat-treated at 268°C for 2 minutes to obtain a heat-shrunk bag-like object. It was visually confirmed that the bag-like object and the contents were tightly adhered due to the heat shrinkage. Furthermore, the joint strength was evaluated by cutting both ends of the joint in the longitudinal direction of the bag-like object using the method described above.

[0037] (Comparative Example 2) As the raw material for the long-fiber nonwoven fabric, polyester with an intrinsic viscosity of 0.63 dl / g and a polyethylene terephthalate component of 99% or more was used. Spinning was performed at a spinning temperature of 285°C from a spinneret with an orifice diameter of φ0.30 mm at a single-hole discharge rate of 1.74 g / min. The material was cooled with 20°C air at a wind speed of 0.75 m / sec from 120 mm directly below the spinneret, and then ejected at a rate of 1.27 kg / cm³ to an ejector positioned 900 mm directly below the spinneret. 2 Dry air was supplied at a certain pressure, the fibers were stretched in one stage, and the fiber bundles were spread and piled up on a conveyor net 1.0 m below, with the speed adjusted to ensure a random fiber arrangement. The single filament fineness was 4.8 dtex, the converted spinning speed was 3600 m / min, and Δn was 69 × 10⁻¹⁴. -3 , with a specific gravity of 1.344 g / cm³ 3 The ratio of dry heat shrinkage rates in the vertical and horizontal directions is 1.01, and the basis weight is 20 g / m². 2A long-fiber nonwoven fabric was obtained.

[0038] Next, an embossing process was performed at 60°C and a linear pressure of 30kN / m using an embossing roll with frustum-shaped protrusions arranged in a staggered pattern and a pressure application area ratio of 8%, which was installed in-line, to obtain a heat-sealed type long-fiber nonwoven fabric. Polyethylene fibers (Tsunooga 440dtex, manufactured by Toyobo Co., Ltd.) were then added to the above heat-sealed type long-fiber nonwoven fabric at a rate of 300 fibers / m. 2 The sheets are arranged in the longitudinal direction, and the above-mentioned heat-sealed type long-fiber nonwoven fabric is layered on top, with a needle density of 51 needles / cm². 2 The entanglement was treated by needle punching with a needle depth of 12 mm (Organ FPD220), resulting in a basis weight of 50 g / m². 2 A long-fiber nonwoven fabric laminate was obtained.

[0039] The above-mentioned long-fiber nonwoven fabric laminate was cut into pieces measuring 11 cm vertically and 5 cm horizontally, and the edges were heat-sealed 1 cm from the end to obtain a bag-like object with a joint. The entire surface of the heat-sealed portion was joined, forming a joint. Contents were placed inside the bag-like object, and it was heat-treated at 268°C for 2 minutes to obtain a heat-shrunk bag-like object. It was visually confirmed that the contents were tightly attached due to the heat shrinkage. Furthermore, the joint strength was evaluated by cutting both ends of the joint in the vertical direction of the bag-like object using the method described above.

[0040] Table 1 shows the measurement results for each physical property.

[0041] [Table 1]

[0042] Table 1 shows that Examples 1-3, in which high-shrinkage fibers with a shrinkage rate of 15% or more at 135°C for 3 minutes are sandwiched between layers of long-fiber nonwoven fabric, and the area shrinkage rate is 30% or more, are highly shrinkable long-fiber nonwovens with excellent strength. Furthermore, because they use polyester with a polyethylene terephthalate component of 99% or more, they also have good recyclability. [Industrial applicability]

[0043] This invention makes it possible to manufacture a shrinkable long-fiber nonwoven fabric composed mainly of a long-fiber nonwoven laminate and high-shrinkage fibers, which exhibits high shrinkage and excellent mechanical strength characteristics across the entire sheet, as well as being lightweight and easy to handle, thereby making a significant contribution to industry.

Claims

1. A laminate of long-fiber nonwoven fabrics, in which at least two long-fiber nonwoven fabrics are laminated together. In the laminate of the long fiber nonwoven fabric, high-shrinkage fibers with a shrinkage rate of 15% or more at 135°C for 3 minutes are present between at least one layer. The area contraction rate is 30% or more. Between the aforementioned layers, there are 50 to 350 of the high-shrinkage fibers per m². A laminate of long-fiber nonwoven fabrics, characterized in that the high-shrinkage fibers are present between the layers substantially parallel to the mechanical direction of the long-fiber nonwoven fabric.

2. Weight: 60-200 g / m ２ The long-fiber nonwoven fabric laminate according to feature 1.

3. The long-fiber nonwoven fabric laminate according to claim 1 or 2, characterized in that the fineness of the high-shrinkage fibers is 22 to 2340 dtex.

4. The long-fiber nonwoven fabric laminate according to claim 1 or 2, characterized in that the high-shrinkage fibers are polyethylene fibers.

5. The long-fiber nonwoven fabric laminate according to claim 1 or 2, characterized in that the transverse shrinkage rate of the long-fiber nonwoven fabric is 15% or more.

6. A long-fiber nonwoven fabric laminate according to claim 1 or 2, characterized in that it is mechanically entangled.

7. A bag-like object using the long-fiber nonwoven fabric laminate described in claim 1 or 2, A bag-like object characterized by having a joint formed by joining the long-fiber nonwoven fabrics together by heat-sealing.

8. The bag-like object according to claim 7, characterized in that it adheres tightly to the contents placed inside the bag-like object by heat shrinkage.

9. The bag-like object according to claim 7, characterized in that the bonding strength at the joint is one-third or less of the base fabric strength of the long-fiber nonwoven fabric.

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