Hot melt adhesive nonwoven fabric

Abstract

To provide a hot melt adhesive nonwoven fabric having all of gas permeability, elasticity, adhesion to olefins and unwindability at high levels.SOLUTION: A hot melt adhesive nonwoven fabric comprises a base resin and a resin compatible with the base resin. The base resin is a styrene-ethylene / butylene-styrene block copolymer having a melt flow rate of 50 to 200 g / 10 minutes at 230°C under a load of 2.16 kg. The resin compatible with the base resin is a low-crystalline homo polypropylene having a melt flow rate of 10 to 200 g / 10 minutes at 230°C under a load of 2.16 kg. The hot melt adhesive nonwoven fabric comprises a resin mixture having a mixing mass ratio between the base resin and the compatible resin of 60 / 40 to 90 / 10.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a hot melt adhesive nonwoven fabric which has excellent handling properties and good adhesion to olefins. [Background technology]

[0002] Hot melt adhesives are solvent-free and provide instant and high-speed adhesion, which are advantageous in terms of the bonding process and economy. Ethylene-based copolymers such as ethylene-vinyl acetate copolymers and thermoplastic polyurethane resins are preferably used as the base resin for hot melt adhesives.

[0003] Since the above hot melt adhesive needs to be applied at a high temperature, a dedicated application device called a hot melt applicator is used for application. Hot melt applicators usually heat the hot melt adhesive to about 120 to 190°C and use compressed air or a gear pump to intermittently discharge (shot) it from the tip of a nozzle to apply it to an adherend. Therefore, thread-like matter is generated between the tip of the nozzle that discharges the hot melt adhesive and the adherend due to the thread-drawing property of the hot melt adhesive, which causes problems of contaminating peripheral devices and adherends during various usage processes.

[0004] In order to suppress the stringing, a method has already been proposed in which a thermoplastic polyurethane resin having hot melt adhesive properties is molded in advance into a sheet such as a film or nonwoven fabric, and the adherend and the hot melt sheet are laminated and heated and pressed together (see Patent Document 1).

[0005] In addition, a method for obtaining an adhesive sheet using an adhesive substance such as a styrene-based elastomer has already been proposed as an adhesive sheet using a resin other than a thermoplastic polyurethane resin having hot melt adhesiveness (see Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3854997 [Patent Document 2] Patent No. 3032091 Summary of the Invention [Problem to be solved by the invention]

[0007] However, Patent Document 1 uses a nonwoven fabric made of a thermoplastic polyurethane resin, which has excellent flexibility, elasticity, and breathability, but the thermoplastic polyurethane resin has poor adhesive compatibility with olefins, and when heat bonding is performed using an olefin nonwoven fabric as an adherend, although it adheres due to the anchor effect, there is a problem that sufficient adhesive strength is not obtained and it easily peels off. In addition, in the case of a film, although the adhesive strength is higher than that of a nonwoven fabric, if the adherend requires breathability, it is not preferable because it inhibits the breathability. In addition, Patent Document 2 uses a nonwoven fabric of a styrene-based elastomer, and since an adhesive substance such as a styrene-based elastomer has adhesiveness at room temperature, there is a problem that if it is rolled up alone without using a separator or the like, it cannot be unwound by self-adhesion. SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a hot melt adhesive nonwoven fabric which is excellent in breathability, stretchability, adhesion to olefins, and releasability. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and have found that by using a resin mixture of styrene-ethylene-butylene-styrene block copolymer and low crystalline homopolypropylene and controlling the melt flow rate and blend ratio of the resin within a certain range, it is possible to obtain an excellent hot melt adhesive nonwoven fabric in which the breathability, stretchability, adhesion to olefins, and unwindability are all within practically acceptable ranges, and have completed the present invention. That is, in order to achieve the above object, the present invention adopts the following configuration. (1) A hot-melt adhesive nonwoven fabric comprising a base resin and a resin compatible with the base resin, the base resin being a styrene-ethylene-butylene-styrene block copolymer having a melt flow rate of 50-200g / 10min at 230°C under a load of 2.16kg, the resin compatible with the base resin being a low-crystalline homopolypropylene having a melt flow rate of 10-200g / 10min at 230°C under a load of 2.16kg, and the mixture ratio of the base resin to the compatible resin being 60:40-90:10 by mass.

[0009] (2) The hot-melt adhesive nonwoven fabric according to (1), characterized in that the adhesive strength is 2 kg / 50 mm or more. (Adhesive strength) Measurements are made in accordance with JIS L 1086 "Test methods for adhesive interlinings and adhesive fabrics." First, we applied a hot melt adhesive nonwoven fabric with a basis weight of 50 g / m 2 The material was sandwiched between two sheets of crystalline polypropylene nonwoven fabric and pressed on one side with a flat auto press HP-54A (made by Hashima Co., Ltd.) at 140°C for 60 seconds at a pressure of 500g / cm. 2 The resulting bonded laminate is left to stand for 30 minutes in an environment with a temperature of 23±2°C and a relative humidity of 50±5%, and then punched out to a width of 50 mm and a length of 10 cm to prepare a measurement sample, and the integrated average load when pulled in a 180° direction to the bonded surface with a gripping distance of 50 mm and a pulling speed of 100 mm / min is regarded as the adhesive strength.

[0010] (3) Weight is 25 to 80 g / m 2 The hot melt adhesive nonwoven fabric according to (1) or (2),

[0011] (4) Air permeability is 500cc / cm 2 / s or more.

[0012] (5) Air permeability is 500cc / cm 2 / s or more.

[0013] (6) The hot-melt adhesive nonwoven fabric according to (1) or (2), characterized in that the breaking elongation is 200% or more.

[0014] (7) The hot-melt adhesive nonwoven fabric according to (3), characterized in that the breaking elongation is 200% or more.

[0015] (8) The hot-melt adhesive nonwoven fabric according to (4), characterized in that the breaking elongation is 200% or more.

[0016] (9) The hot-melt adhesive nonwoven fabric according to (5), characterized in that the breaking elongation is 200% or more. Effect of the Invention

[0017] According to the present invention, it is possible to obtain a hot melt adhesive nonwoven fabric having excellent breathability, elasticity, adhesion to olefins, and releasability. In addition, since the obtained nonwoven fabric has excellent breathability and elasticity, it can be flexibly bonded to the shape of the object to be bonded. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The hot melt adhesive nonwoven fabric of the present invention is obtained by forming a nonwoven fabric from a resin mixture of a base resin, styrene-ethylene-butylene-styrene block copolymer (SEBS), and a low-crystalline homopolypropylene that is compatible with the base resin.

[0019] The SEBS in the present invention must have a melt flow rate of 50 to 200 g / 10 min at 230° C. and a load of 2.16 kg. The melt flow rate is preferably 60 to 190 g / 10 min. If the melt flow rate is 50 g / 10 min or more, the fibers can be sufficiently thinned to obtain a nonwoven fabric. If the melt flow rate is 200 g / 10 min or less, the fibers are easily solidified and the nonwoven fabric is easily unwound when wound into a roll. In addition, a nonwoven fabric having continuous fibers with few thread breaks can be obtained. If thread breaks occur, there are places where the fibers are accumulated in a granular form rather than in a fibrous form, which causes a decrease in adhesive strength. However, if there are few thread breaks, the fibers are uniformly accumulated as a nonwoven fabric, resulting in high adhesive strength.

[0020] The low-crystalline homopolypropylene used in the present invention is most preferably a low-crystalline homopolypropylene having a crystal fusion heat and crystallization heat of less than 30 J / g in differential scanning calorimetry. The heat of crystalline fusion and the heat of crystallization can be measured by differential scanning calorimetry (DSC) using the ASTM-E-794-95 procedure. The low crystalline homopolypropylene in the present invention must have a melt flow rate of 10 to 200 g / 10 min at 230° C. and a load of 2.16 kg. The melt flow rate is preferably 30 to 170 g / 10 min. If the melt flow rate is 10 g / 10 min or more, the fibers can be sufficiently thinned to obtain a nonwoven fabric. If the melt flow rate is 200 g / 10 min or less, the fibers are easily solidified and the nonwoven fabric is easily unwound when wound into a roll. In addition, a nonwoven fabric with continuous fibers with few thread breaks can be obtained, and the fibers are uniformly deposited as a nonwoven fabric, resulting in high adhesive strength. In addition, the low crystalline homopolypropylene has fewer thread breaks than crystalline polypropylene, and the fibers are uniformly deposited as a nonwoven fabric, resulting in high adhesive strength.

[0021] The resin mixture of SEBS and low crystalline homopolypropylene in the present invention must have a mixing ratio by mass of 60:40 to 90:10, and preferably 70:30 to 80:20. If the SEBS content is 60% or more, the hot melt adhesiveness and stretchability are excellent, and if it is 90% or less, the tackiness at room temperature is suppressed and the resin is easily unwound when wound into a roll.

[0022] The hot melt adhesive nonwoven fabric of the present invention has a basis weight of 25 to 80 g / m 2 It is preferable that the thickness is 40 to 60 g / m 2 More preferably, it is 25 g / m 2 If the adhesive has a thickness of 80 g / m or more, the adhesive area is large, there are no adhesive spots, and the adhesive strength is excellent. In addition, when unwound after being wound into a roll, the adhesive has sufficient stiffness, does not cling to the surface due to static electricity, and is easy to handle. 2 If it is less than this, the breathability is excellent.

[0023] The hot melt adhesive nonwoven fabric of the present invention has an air permeability of 500 cc / cm 2 / s or more is preferable. 2 If the viscosity is 100 / s or more, adhesion can be achieved without impairing the breathability of the adherend, even when the adherend requires breathability.

[0024] The hot melt adhesive nonwoven fabric of the present invention preferably has a breaking elongation of 200% or more. If it is 200% or more, it can be used even when the object to be bonded is one that bends or stretches.

[0025] The hot melt adhesive nonwoven fabric of the present invention preferably has an adhesive strength of at least 2 kg / 50 mm, as described below. If the adhesive strength is at least 2 kg / 50 mm, the hot melt adhesive nonwoven fabric for adhering olefin has excellent hot melt adhesive properties.

[0026] The hot melt adhesive nonwoven fabric of the present invention can be produced by the melt blowing method, the spunbonding method, etc., among which the melt blowing method is preferred. The nonwoven fabric obtained by the melt blowing method has good stretchability and flexibility. EXAMPLES

[0027] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Evaluations in the examples were performed as follows.

[0028] (MFR of resin) In accordance with JIS K 7210 "Plastics - Determination of melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics", measurements were taken using a half-size die with a nominal length of 4,000 mm and a nominal hole diameter of 1,050 mm at a temperature of 230°C and a load of 2.16 kg.

[0029] (Various test atmospheres for nonwoven fabrics) Various tests of the nonwoven fabric were performed at a temperature of 23±2°C and a relative humidity of 50±5%. The samples were conditioned in the same atmosphere for 24 hours before the following tests were performed.

[0030] (Weight) In accordance with JIS L 1913 "General nonwoven fabric test method", the weight of a 250 x 250 mm test piece was measured and 2 Converted to per.

[0031] (Elongation at break) In accordance with JIS L 1913 "Test methods for general nonwoven fabrics," a piece of nonwoven fabric 20 mm wide and 10 cm long was cut into a straight piece with the long side in the MD or CD direction and pulled straight on a tensile tester with a gripping distance of 50 mm and a pulling speed of 200 mm / min, and the elongation at which the nonwoven fabric broke was read.

[0032] (Adhesive strength) Measurements were made in accordance with JIS L 1086 "Test methods for adhesive interlinings and adhesive fabrics." Specifically, first, a hot melt adhesive nonwoven fabric with a basis weight of 50 g / m 2The material was sandwiched between two sheets of crystalline polypropylene nonwoven fabric and pressed on one side with a flat auto press HP-54A (made by Hashima Co., Ltd.) at 140°C for 60 seconds at a pressure of 500g / cm. 2 The resulting adhesive laminate was left to stand for 30 minutes in an environment with a temperature of 23±2°C and a relative humidity of 50±5%, and then punched out to a measurement sample with a width of 50 mm and a length of 10 cm. The integrated average load when pulled in a 180° direction to the adhesive surface with a gripping distance of 50 mm and a pulling speed of 100 mm / min was defined as the adhesive strength.

[0033] Example 1 A mixture of SEBS with a melt flow rate of 180 g / 10 min and low crystalline homopolypropylene with a melt flow rate of 50 g / 10 min was weighed and mixed in a weight ratio of 80:20, and the mixture was melt-blow spun. The resulting molten fiber group was dropped onto a net conveyor and spun into a fiber with a basis weight of 50 g / m. 2 The hot melt adhesive nonwoven fabric was obtained. The obtained nonwoven fabric was wound around a paper tube in a roll shape to obtain a nonwoven fabric roll. The basis weight and breaking elongation of the obtained nonwoven fabric were measured. Also, an adhesive strength test was performed using the obtained nonwoven fabric.

[0034] Example 2 A hot-melt adhesive nonwoven fabric was obtained in the same manner as in Example 1, except that the melt flow rate of the SEBS was 70 g / 10 min.

[0035] Example 3 A hot-melt adhesive nonwoven fabric was obtained in the same manner as in Example 1, except that the mixing ratio of SEBS and low-crystalline homopolypropylene was 60:40.

[0036] Example 4 Weight: 75g / m 2 A hot-melt adhesive nonwoven fabric was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0037] Example 5 Weight: 25g / m 2 A hot-melt adhesive nonwoven fabric was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0038] Comparative Example 1 A nonwoven fabric was obtained in the same manner as in Example 1, except that the melt flow rate of the low crystalline homopolypropylene was 390 g / 10 min. When the obtained nonwoven fabric was wound around a paper tube, it could not be unwound due to fusion of the nonwoven fabric layers, and therefore could not be used as a hot melt adhesive nonwoven fabric.

[0039] Comparative Example 2 The mixture was melt-blow spun in the same manner as in Example 1, except that a crystalline polypropylene with a melt flow rate of 60 g / 10 min was used as the resin compatible with the base resin. However, a nonwoven fabric could not be obtained because the fibers were cut by blowing.

[0040] Comparative Example 3 A nonwoven fabric was obtained by melt blow spinning in the same manner as in Example 1, except that the mixing ratio of SEBS and low-crystalline homopolypropylene was 95:5. When the obtained nonwoven fabric was wound up on a paper tube, it could not be unwound due to fusion of the nonwoven fabric layers, and therefore could not be used as a hot-melt adhesive nonwoven fabric.

[0041] Comparative Example 4 A nonwoven fabric was obtained in the same manner as in Example 1, except that a mixture of SEBS with a melt flow rate of 70 g / 10 min and crystalline polypropylene with a melt flow rate of 60 g / 10 min was used, which was weighed and mixed in a weight ratio of 50:50. The obtained nonwoven fabric was wound around a paper tube to obtain a hot melt adhesive nonwoven fabric roll.

[0042] Comparative Example 5 A thermoplastic polyurethane resin with a flow start temperature of 105°C and a melt flow rate of 90g / 10min was melt-blow spun, and the resulting molten fiber group was dropped onto a net conveyor and spun to a basis weight of 50g / m 2 The resulting nonwoven fabric was wound around a paper tube to obtain a hot melt adhesive nonwoven fabric roll.

[0043] These results are also shown in Table 1. [Table 1]

[0044] All of the nonwoven fabrics in Examples 1 to 5 were excellent in breathability, elasticity, adhesion to olefin, and unwindability. These nonwoven fabrics are excellent in breathability and elasticity, so they can be flexibly bonded to the shape of the object to be bonded.

[0045] In both Comparative Examples 1 and 3, the nonwoven fabrics were fused together and could not be unwound. In Comparative Example 2, the fibers were cut and piled up in granular form, making it impossible to obtain a nonwoven fabric. In both Comparative Examples 4 and 5, the adhesive strength was insufficient, and the fabrics were not suitable for use as hot-melt adhesive nonwoven fabrics. [Industrial Applicability]

[0046] The hot-melt adhesive nonwoven fabric of the present invention can be suitably used as a hot-melt adhesive nonwoven fabric for bonding olefins, and is also suitable for use in applications requiring stretchability and breathability.

Claims

1. The hot-melt adhesive nonwoven fabric is made of a base resin and a resin compatible with the base resin, the base resin being a styrene-ethylene-butylene-styrene block copolymer having a melt flow rate of 50 to 200 g / 10 min at 230°C under a load of 2.16 kg, the resin compatible with the base resin being a low-crystalline homopolypropylene having a melt flow rate of 10 to 200 g / 10 min at 230°C under a load of 2.16 kg, and the hot-melt adhesive nonwoven fabric is made of a resin mixture in which the mixing ratio of the base resin to the compatible resin is 60:40 to 90:10 by mass.

2. 2. The hot melt adhesive nonwoven fabric according to claim 1, characterized in that the adhesive strength is 2 kg / 50 mm or more. (Adhesive strength) The measurement is performed in accordance with JIS L 1086 "Test methods for adhesive interlinings and adhesive fabrics." First, a hot melt adhesive nonwoven fabric with a basis weight of 50 g / m ２ The sheet was sandwiched between two sheets of crystalline polypropylene nonwoven fabric and pressed on one side with a flat auto press HP-54A (made by Hashima Co., Ltd.) at 140°C for 60 seconds at a pressure of 500g / cm. ２ The obtained adhesive laminate is allowed to stand for 30 minutes in an environment of a temperature of 23±2° C. and a relative humidity of 50±5%, and then a measurement sample of 50 mm in width and 10 cm in length is punched out, and the integrated average load when pulled in a direction of 180° to the adhesive surface with a gripping distance of 50 mm and a pulling speed of 100 mm / min is defined as the adhesive strength.

3. Weight per unit area: 25 to 80 g / m ２ 3. The hot melt adhesive nonwoven fabric according to claim 1, wherein

4. Air permeability is 500cc / cm ２ 3. The hot melt adhesive nonwoven fabric according to claim 1, wherein the elastic modulus is 1 / s or more.

5. Air permeability is 500cc / cm ２ 4. The hot melt adhesive nonwoven fabric according to claim 3, wherein the elastic modulus is 1 / s or more.

6. 3. The hot melt adhesive nonwoven fabric according to claim 1, wherein the breaking elongation is 200% or more.

7. 4. The hot melt adhesive nonwoven fabric according to claim 3, wherein the breaking elongation is 200% or more.

8. 5. The hot melt adhesive nonwoven fabric according to claim 4, which has a breaking elongation of 200% or more.

9. 6. The hot melt adhesive nonwoven fabric according to claim 5, wherein the breaking elongation is 200% or more.

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