JP2000192361A - Spun-bonded non-woven fabric and diaper using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spun-bonded non-woven fabric capable of lowering a sealing temperature on the production of a diaper, consequently capable of maintaining the excellent flexibility and touch of sealed portions, and excellent in strength and continuous productivity, and to provide the diaper comprising the spun-bonded non-woven fabric. SOLUTION: This spun-bonded non-woven fabric comprises a resin material containing at least one of propylene-α-olefin random copolymers and satisfying the following conditions (A) to (D). (A) The content of the propylene-α-olefin random copolymer is 2-10 mol.%. (B) The melting peak temperature is <=150 deg.C. (C) The melt index (230 deg.C, 2.16 kg) is 10-100 g/10 min. (D) The mol. wt. distribution (Mw/Mn) is 2.0-6.0. A diaper uses the spun-bonded non-woven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spunbonded nonwoven fabric and a diaper, and more particularly to a specific propylene-α.
The present invention relates to a spunbonded nonwoven fabric and a diaper obtained by using a resin material containing an olefin random copolymer.

[0002]

2. Description of the Related Art Spunbonded nonwoven fabrics made of continuous long fibers are higher in strength and relatively inexpensive than staple fibers, so-called short fiber nonwoven fabrics made of so-called short fibers, and are therefore used as sanitary materials, industrial materials, and civil engineering materials. It is widely used as general living materials. In particular, a polypropylene spunbond nonwoven fabric made of long polypropylene fibers is widely used as a sanitary material such as diapers because it has high strength and is relatively inexpensive while having softness.

At present, disposable diapers need to be provided with various advanced functions in order to respond to various needs from consumers. For this reason, it is common to use a combination of a plurality of materials instead of a single material. Is being done. In this case, in the diaper production line, as a method of integrating and bonding each material, a method of applying a hot melt when bonding each material on a surface is adopted, and an emboss pattern is used when bonding with a line. A method using a heat seal is used.

By the way, disposable diapers are roughly classified into two types. That is, an adhesive tape for attachment and detachment is attached to an hourglass-shaped flat sheet, and in mounting, a so-called fastening type in which a front part and a rear part are joined with this adhesive tape on both sides of the waist. It is a so-called wearing type in which the front body and the back body are already joined at the side and are in the form of pants.

[0005] In both of these types, the sheet body portion has a top sheet made of a liquid-permeable material that comes into direct contact with urine on the side that the skin touches when worn, and urine leakage on both sides of the top sheet. There is a side sheet that is arranged through three-dimensional gathers and the like provided for the purpose of prevention, and the sheet on the side that is outside at the time of mounting (referred to as "back sheet") is a liquid-impermeable material alone or liquid-impermeable A laminated composite flat sheet having a liquid-absorbing material layer or the like disposed between the back sheet and the sheet on which the skin comes into contact is used.

When using such a laminated composite flat sheet, in the case of the above-mentioned fastening type, the flat sheet cut out in the shape of an hourglass may be used as it is, whereas in the case of the type to be worn, an hourglass type may be used. It is necessary to fold a flat sheet of the shape of with the top sheet and the side sheet side inside at the part that hits the crotch part, join the waist part leaving the part where the foot passes, and shape it into pants-like shape Become. That is, in such a process,
The top sheet and the side sheet side that were bent and met, that is, the front body and the back body were joined together at the side to form a pants-like shape, but at the joint, the flat sheet overlapped doubly. In this state, the double overlapped portions are bonded by heating and pressing.

As described above, in the case of the type to be worn, a material in which the nonwoven fabric sheet or film usually overlaps 4 to 6 layers, and in many cases, as many as 10 layers, is integrated by a single heat seal. In that case, all the materials had to be fused, and the sealing temperature had to be raised in order to sufficiently transmit heat to each layer. However, when the sealing temperature is increased, the sealing portion and its peripheral portion are in a state in which heat is excessively applied, so that the overheated portion becomes hard,
The problem that the fit to skin deteriorates extremely has been raised. In addition, the speed itself of the diaper production line has decreased, and problems in productivity have been pointed out.

[0008] In particular, recently, a type that can be worn without fear of loosening at the adhesive tape portion has been preferred, and it has been desired to solve the above problem.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and it is possible to lower the sealing temperature at the time of manufacturing a diaper, and as a result, to maintain the softness and excellent texture of the sealing portion. It is an object of the present invention to provide a spunbonded nonwoven fabric and a diaper that can be manufactured and have excellent strength and continuous productivity.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the spunbonded nonwoven fabric obtained by using a resin material containing a specific propylene-α-olefin random copolymer is the present invention. It has been found that the object of the invention can be effectively achieved, and the present invention has been completed. That is, the present invention provides the following spunbonded nonwoven fabric and diaper. (1) A resin material containing at least one kind of propylene-α-olefin random copolymer, wherein
(D) A spunbond nonwoven fabric formed of a material that satisfies (d). (A) In the propylene-α-olefin random copolymer, the content of α-olefin is 2 to 10 mol%
That. (A) The melting peak temperature (Tm) is 150 ° C. or less. (C) Melt index (MI) (230 ° C, 2.16
kg) is 10 to 100 (g / 10 minutes). (D) The molecular weight distribution (Mw / Mn) is from 2.0 to 6.0. (2) The spunbonded nonwoven fabric according to the above (1), wherein in the at least one propylene-α-olefin random copolymer, the α-olefin is at least one selected from ethylene and 1-butene. (3) A diaper using the spunbonded nonwoven fabric according to the above (1) or (2).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. 1. Material used for spunbonded nonwoven fabric according to the present invention (1) A resin material containing at least one or more propylene-α-olefin random copolymers, and
(D) must be satisfied. (A) In the propylene-α-olefin random copolymer, the content of α-olefin is 2 to 10 mol%
That.

If the content of α-olefin is less than 2 mol%, the melting temperature required for low-temperature sealing cannot be lowered. The content of such α-olefin is preferably 3 to 9 mol%. Here, preferred α-olefins include ethylene and / or 1-butene from the viewpoint that low-temperature sealing properties can be obtained effectively and the texture is soft. That is, a propylene-ethylene random copolymer or a propylene-1-butene random copolymer,
Furthermore, a propylene-ethylene-1-butene random terpolymer is mentioned. In the case of such a terpolymer, the total amount of ethylene and 1-butene needs to be 2 to 10 mol%. There are no particular restrictions on the proportions of ethylene and 1-butene, and the proportions of the two may be appropriately selected according to the purpose.

[0013] The method for producing the propylene-α-olefin random copolymer is not particularly limited, and it may be obtained using a metallocene-based catalyst. (A) The melting peak temperature (Tm) is 150 ° C. or less. Here, the melting peak temperature (Tm) is a value measured using a DSC7 type differential scanning calorimeter manufactured by Perkin Elmer Co., Ltd., and is obtained as follows. That is, 10 mg of a sample was previously melted in a nitrogen atmosphere at 230 ° C. for 3 minutes, then cooled at a rate of 10 ° C./min to 20 ° C., held at this temperature for 3 minutes, and then heated at a rate of 10 ° C./min. The peak top temperature of the maximum peak in the melting endothermic curve was defined as the melting peak temperature (Tm). If the melting peak temperature (Tm) exceeds 150 ° C., the sealing temperature for making a diaper cannot be sufficiently lowered. The melting peak temperature (Tm) is preferably 148 ° C. or lower. (C) Melt index (MI) (230 ° C, 2.16
kg) is 10 to 100 (g / 10 minutes).

The melt index is based on ASTM D12
38, 230 ° C, 2.16
It is a value under the condition of kg. When the MI is less than 10 g / 10 minutes, there is a possibility that problems such as poor flow characteristics and fiber forming ability, yarn breakage during molding and denier reduction cannot be achieved. On the other hand, if it exceeds 100 g / 10 minutes, the mechanical strength may be inferior when formed into a nonwoven fabric. MI is preferably 20 to 60 g / 10 min. (D) The molecular weight distribution (Mw / Mn) is from 2.0 to 6.0.

If the molecular weight distribution (Mw / Mn) exceeds 6, spinnability may be poor. (2) The resin material used in the present invention contains at least one or more propylene-α-olefin random copolymers. That is, only one kind of propylene-α-olefin random copolymer may be used, a mixture of plural kinds of propylene-α-olefin random copolymers may be used, and one or more kinds of propylene-α-olefin random copolymers may be used. May be mixed with another resin, preferably a polyolefin resin. Further, if necessary, an antioxidant, an ultraviolet absorber, a coloring agent, an antistatic agent, a weathering agent, and the like which are usually used for fibers and nonwoven fabrics may be added. 2. Spunbonded nonwoven fabric according to the present invention (1) Manufacturing method A spunbonded nonwoven fabric according to the present invention can be manufactured by a known spunbonding method.

In the spinning process, a method using an ejector or air sucker using high-pressure air,
Either a method using a throttle plate or a method using both of them in order to increase the air speed by using a suction blower to seal the air guide path may be used, and the method is not particularly limited thereto. (2) Properties of Spunbonded Nonwoven Fabric In the spunbonded nonwoven fabric according to the present invention, the basis weight is not particularly limited, but is preferably from 10 to 100 g / m ² , and more preferably from 15 to 50 g / m ² from the viewpoint of good texture.
m ² , more preferably in the range of 15 to 30 g / m ² . Further, the fiber diameter is desirably in the range of 10 to 100 μm, preferably 15 to 50 μm. 3. Diaper according to the present invention The diaper according to the present invention uses the above spunbonded nonwoven fabric as a sheet on the side that comes into contact with the skin, preferably as a sidesheet. The spunbonded nonwoven fabric can be applied to both fastening and disposable types of disposable diapers. Particularly, when producing disposable diapers of the wearable type, the effect is extremely advantageously exhibited. (1) Manufacturing method In the case of the fastening type, the spunbonded nonwoven fabric is used as a top sheet or a side sheet in a flat sheet obtained by cutting into an hourglass shape, and an adhesive tape for detachment is attached. Can be manufactured.

Further, in the case of the fastening type, the sealing structure is not as complicated as that of the waist portion of the type worn, but the joining of the liquid-permeable top sheet and the hydrophobic side sheet is performed by using a heating roll or the like. Generally, they are bonded by heating. Wearable disposable diapers are usually folded with a flat composite sheet obtained by cutting into an hourglass shape, with the top sheet or side sheet side inward at the border of the crotch area, leaving a part through which the foot passes. It can be manufactured by joining the waist portion and shaping into a pants shape. In this case, as shown in FIG. 1, the side sheets which have been folded and come into contact with each other, that is, the front body and the back body are joined together by so-called palm attachment to form a pants shape. The joining portion is in a state in which the flat composite sheet is doubly overlapped, and the doubly overlapped portion can be heat-pressed with a heating roll or the like so as to be bonded together.

A liquid-absorbing material layer in which pulp, a water-absorbing polymer or the like is wrapped with a tissue or the like is usually inserted between a top sheet and a back sheet at a site where absorption of urine or the like is required such as a crotch portion. You.

[0019]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. (1) The evaluation of the resin material used was performed by the following method. Melting peak temperature (Tm) A DSC7 type differential scanning calorimeter manufactured by PerkinElmer was used for the measurement. A 10 mg sample was previously melted in a nitrogen atmosphere at 230 ° C. for 3 minutes, then cooled at a rate of 10 ° C./minute to 20 ° C., held at this temperature for 3 minutes, and then heated at a rate of 10 ° C./minute to obtain a melting endotherm. The peak top temperature of the maximum peak in the curve was defined as the melting peak temperature (Tm). Melt index (MI) is a value measured in accordance with ASTM D1238, and is a value measured under the conditions of a load of 2.16 kg and a temperature of 230 ° C. Molecular weight distribution (Mw / Mn) Measured by gel permeation chromatography, and the measurement conditions are as follows. The ratio between the weight average molecular weight Mw and the number average molecular weight Mn is determined by the molecular weight distribution (Mw / M
n).

Column: TOSO BMHHR-H (S)
HT solvent: 1,2,4 trichlorobenzene Column temperature: 145 ° C. Flow rate: 1.0 ml / min Calibration curve: Universal Calibration Detector: RI (Waters 150C) Analysis program: HT-GPC (Ver. 1.0) ( 2) Formation and evaluation of nonwoven fabric The configuration of the apparatus used was a 45 mmφ single screw extruder, a die and nozzle for spun bonding, a cooling tower, a filament pulling apparatus, a fiber opening apparatus, a conveyor, an embossing roll, and a winding order. . Here, the number of nozzles is 452, the hole diameter of the nozzles is 0.4 mmφ, the discharge amount per nozzle is 0.42 g / min, and the diameter is 0.4 m in a closed wind guide system (Lycofil model) which is a spinning traction device. A web of width was formed. The embossing roll in the thermocompression bonding step uses an induction heating roller (roll diameter 300 mmφ, grid pattern of 0.6 mm square with an area compression ratio of 13%) manufactured by Tokuden Co., and the embossing pressure (linear pressure) is 30 kg / cm. went. As a basic condition, a nonwoven fabric of 20 g / m ² was obtained, and the speed of the conveyor and the embossing roll was 24 m / min.

The evaluation of the obtained nonwoven fabric was performed by the following method. Bending resistance (mm) Determined by the 45 ° cantilever method in accordance with JIS L1096. The smaller the value, the softer the texture. Tensile strength (kg / 5 cm) In accordance with JIS L1096, the test was performed at a test specimen width of 5 cm, a grip interval of 10 cm, and a tensile speed of 30 cm / min. Seal temperature The diaper seal portion using the nonwoven fabric according to the present invention for the outermost layer was simplified, and the seal strength was measured at each temperature when the seal temperature was changed under the following seal conditions.
The temperature at which a sealing strength of 0 g / 15 mm was obtained was defined as the sealing temperature. The softness of the seal was evaluated by hand. <Seal Condition> A heat seal bar having a lattice pattern of 0.6 × 0.6 mm with a compression area of 45% was used, the seal time was 1 second, and the seal pressure was 2 kg / cm ² . <Structure of Sealing Part> The resulting nonwoven fabric is used as a sealing layer nonwoven fabric, a polyethylene film 25 μm, and a composite nonwoven fabric 22 g / m ² using a polyethylene / polyester composite fiber as the outermost layer, as shown in FIG. Sealed. Example 1 6.2 mol% of ethylene, MI = 24, Tm
= 132 ° C., Mw / Mn = 3.3 propylene-ethylene random copolymer (trade name “Y” manufactured by Idemitsu Petrochemical Co., Ltd.)
-2045GP ") as a resin material, extruding a resin at a resin temperature of 215 ° C from a die of an extruder, drawing and thinning with air to form a yarn (filament), and randomly collecting the yarn to form a sheet (web). ) And the temperature is 11
Point-adhesion with a 5 ° C. hot embossing roll gives a basis weight of 20
g / m ² of nonwoven fabric was obtained. The moldability into a nonwoven fabric was good.

The evaluation results are shown in Tables 1 and 2.

[0023]

[Table 1]

[0024]

[Table 2]

[Example 2] (Preparation of magnesium compound) The reaction layer equipped with a stirrer (80 L internal volume) was sufficiently replaced with nitrogen gas, and dehydrated ethanol 2
0L, 1.06kg of metallic magnesium and 106 of iodine
g, and the mixture was reacted with stirring under reflux conditions until hydrogen gas was no longer generated from the inside of the system to obtain a solid reaction product. The reaction product containing the solid reaction product was dried under reduced pressure to obtain a target magnesium compound (a solid catalyst carrier). (Preparation of solid catalyst component) 4.0 kg of the magnesium compound was added to a reaction layer equipped with a stirrer (internal volume: 80 L) which was replaced with nitrogen.
, And 20 L of dehydrated heptane was further added. Heat to 40 ° C and add 600 ml of silicon tetrachloride,
Then, 850 ml of di-n-butyl phthalate was added. The temperature of the solution was raised to 70 ° C., and then 19.25 L of titanium tetrachloride was charged. The internal temperature was set to 125 ° C., and a contact reaction was performed for 2 hours. Thereafter, washing was sufficiently performed using dehydrated heptane at 125 ° C. 30.50 L of titanium tetrachloride
In addition, the internal temperature was set to 125 ° C., and a contact reaction was performed for 2 hours. Thereafter, washing was carried out sufficiently using dehydrated heptane at 125 ° C. to obtain a solid catalyst component [A]. (Preliminary polymerization) Nitrogen-replaced reaction layer with stirrer (internal volume 8
0 L), 1.0 kg of the solid component [A] was charged, and 8.4 L of dehydrated heptane was further added. The mixture was heated to 40 ° C., and 43 ml of triethylaluminum and 116 ml of dicyclopentyldimethoxysilane were added. Propylene was allowed to flow at normal pressure and reacted for 2 hours. Thereafter, the solid component was sufficiently washed with dehydrated heptane to obtain a catalyst component. (Polymerization) The above solid catalyst component was added to a polymerization tank with a stirrer having an internal volume of 200 L in an amount of 3 mmol / kg in terms of titanium atoms in the component.
-4 mmol / kg of triethylaluminum with PP
-PP with dicyclopentyldimethoxysilane in 0.4
mmol / kg-PP, and the polymerization temperature is 75
C., propylene, ethylene and 1-butene were reacted at a polymerization pressure (total pressure) of 24 kg / cm ² G. At this time, the ethylene supply amount was adjusted so as to have a predetermined ethylene content, the 1-butene supply amount was adjusted so as to have a predetermined 1-butene content, and the hydrogen supply amount of the molecular weight regulator was further adjusted so as to have a predetermined molecular weight. . When the gas composition in the polymerization apparatus at this time was analyzed by gas chromatography, the ethylene concentration was 3.2 mol%, the 1-butene concentration was 4.0 mol%, and the hydrogen concentration was 11.0 mol%. (Pelletization and film formation) Tetrakis- (2,4) was added to the propylene-based random copolymer powder thus obtained.
-Di-tert-butylphenyl) -biphenylenediphosphonite (SANDOZSTAB manufactured by Clariant)
0.1 part by weight of P-EPQ) and 0.1 part by weight of calcium stearate, and further adjusted to a predetermined molecular weight.
170 ppm of 5-bis (tert-butylperoxy) hexane (Kayahexa AD manufactured by Kayaku Akzo) was added,
Pellets were formed with a Model 35B extruder manufactured by Toshiba Machine Co., Ltd.

The ethylene content 4.4 mol% and the 1-butene content 3.7 mol%, MI = 22, Tm
= 122 ° C., Mw / Mn = 3.2, and a propylene-ethylene / butene random copolymer was prepared in the same manner as in Example 1.
The embossing roll temperature was 102 ° C., and the basis weight was 20 g / m ^2.
Was obtained. The moldability into a nonwoven fabric was good. The evaluation results are shown in Tables 1 and 2. Example 3 3.3 mol% of ethylene, MI = 40, Tm
= 148 ° C, Mw / Mn = 3.6 propylene-ethylene random copolymer (Idemitsu Petrochemical Co., Ltd., trade name “Y-
4023G ”), the embossing roll temperature was set to 125 ° C., and a nonwoven fabric having a basis weight of 20 g / m ² was obtained in the same manner as in Example 1. The moldability into a nonwoven fabric was good.

The evaluation results are shown in Tables 1 and 2. Comparative Example 1 MI = 60, mp = 161 ° C., Mw / Mn
= 3.2 homopolypropylene (made by Idemitsu Petrochemical Co., Ltd.
In the same manner as in Example 1, the embossing roll temperature was set to 145 ° C. and the basis weight was 20 g /
It was obtained m ² of non-woven fabric. The moldability into a nonwoven fabric was good.

The evaluation results are shown in Tables 1 and 2.

[0029]

According to the present invention, the sealing temperature at the time of diaper production can be lowered, and as a result, the softness and excellent texture of the sealing portion can be maintained, and the strength and the continuous productivity can be maintained. Thus, a spunbonded nonwoven fabric and a diaper excellent in the above were obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a disposable diaper of a wearable type in which a front body and a back body are attached to a palm at a waist side.

FIG. 2 is a schematic diagram of a configuration of a seal portion in the embodiment.

[Explanation of symbols]

 1: Joint between front and back body 2: Composite nonwoven fabric 3: Polyethylene film 4: Sealing nonwoven fabric 5: Seal interface

Claims (3)

[Claims] 1. A spunbond nonwoven fabric formed of a resin material containing at least one random propylene-α-olefin copolymer and satisfying the following (A) to (D). (A) In the propylene-α-olefin random copolymer, the content of α-olefin is 2 to 10 mol%
That. (A) The melting peak temperature (Tm) is 150 ° C. or less. (C) Melt index (MI) (230 ° C, 2.16
kg) is 10 to 100 (g / 10 minutes). (D) The molecular weight distribution (Mw / Mn) is from 2.0 to 6.0. 2. The spunbonded nonwoven fabric according to claim 1, wherein in the at least one propylene-α-olefin random copolymer, the α-olefin is at least one selected from ethylene and 1-butene. . 3. A diaper using the spunbond nonwoven fabric according to claim 1.