JPH0911404A - Multilayer sheet and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a multilayer sheet usable for construction works, civil engineering works, etc., which is a sheet excellent in every kind of a mechanical stength, resistances to water and weather, flexibility, etc., and provide a manufacture suitable for such a multilayer sheet. CONSTITUTION: This multilayer sheet is composed of a nonwoven fabric formed of isotactic polypropylene fibers and a propylene-based thermoplastic elastomer layer laminated on at least one face of the nonwoven fabric.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer sheet made of a non-woven fabric made of isotactic polypropylene fibers and a propylene thermoplastic elastomer, and a method for producing the same.

[0002]

2. Description of the Related Art Various sheets having excellent mechanical strength, water resistance, weather resistance, flexibility, etc. are used for construction work and civil engineering work in order to prevent rain and wind or accidents during these works. ing. Factors that influence these properties are the chemical material of the sheet constituent material and the physical structure of the sheet. Usually, a single-layer sheet and a multi-layer sheet made of a chemically single material, and a multi-layer made of chemically dissimilar materials. There is a sheet.

A single-layer sheet made of a chemically single material is produced by simply extruding a thermoplastic material such as high-density polyethylene resin, polyvinyl chloride resin, polyester resin (usually polyethylene terephthalate). There is a manufacturing characteristic that it can be obtained by a molding method or a calendar molding method, but it is difficult for a single chemical material to satisfy all the above-mentioned characteristics, and it is based on the physical structure of a single-layer sheet in terms of mechanical strength. There are problems, such as low burst strength and low tear propagation strength, which make the molded article somewhat unattractive.

Adhesion of a multilayer sheet made of a chemically single material, for example, a polypropylene resin sheet and a polypropylene resin biaxially stretched sheet, a polypropylene resin stretch tape woven fabric, a polypropylene resin fiber nonwoven fabric, etc. In the case of producing without using a chemical agent, even if an attempt is made to melt-bond the former polypropylene resin sheet having a lower melting point to the latter sheet etc., since the chemical materials are originally the same, the melting point is close, so the latter There is a drawback that the desired multi-layered sheet cannot be obtained by destroying the molecular orientation due to the stretching of the sheet or the like and losing the stretching effect. This problem is the same in the case where the polypropylene resin is melt-extruded into a sheet shape on the surface of the biaxially stretched polypropylene resin sheet.

A multi-layer sheet made of chemically different materials, for example, a low-density polyethylene resin sheet and a woven cloth using polypropylene resin stretched tape, a non-woven cloth made of polypropylene resin fibers, etc., is manufactured without using an adhesive. In this case, even if the melting point difference is quite large, even if the former low-density polyethylene resin sheet is attempted to be melt-bonded to the latter sheet or the like, melt-bonding itself is impossible and a multilayer sheet cannot be manufactured. When an ethylene-vinyl acetate copolymer resin is used instead of the low-density polyethylene resin, melt adhesion is possible, but water resistance,
Problems with the material itself such as weather resistance and surface contamination will also occur,
It is not easy to select and combine chemically different materials.

[0006]

Therefore, an object of the present invention is to provide a sheet having various mechanical strength, water resistance, weather resistance, flexibility, etc., which is a multi-layer used for construction work, civil engineering work and the like. It is to provide a sheet and a suitable method for producing such a multilayer sheet.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve this problem. As a result, they are polypropylene-based resins, which are common in some respects, but different types of polypropylene having different molecular structures with respect to stereoregularity. The present invention has been completed, and the present invention has been found to be solved by using a resin based on one sheet that is a non-woven fabric having a high melting point, and by laminating the other polymer having a low melting point and heating and pressing at a temperature below the melting point. did.

That is, the gist of the present invention is (1) a multilayer sheet in which a layer of a propylene-based thermoplastic elastomer is laminated on at least one surface of a non-woven fabric made of fibers made of isotactic polypropylene. (Second) The propylene-based thermoplastic elastomer is (a)
(A) Isotope carbon nuclear magnetic resonance spectrum ( ¹³ C-NM
In the pentad fraction by R), rrrr / (1-
mmmm) × 100 is 20 to 60%, (b) melting peak temperature (T measured by a differential scanning calorimeter (DSC))
m) is 150 ° C. or higher and (c) a propylene homopolymer having a melting enthalpy (ΔH) measured by DSC of 100 J / g or less and / or a copolymer containing 4 wt% or less of other olefin units. 100 to 20% by weight,
(B) The multilayer sheet according to the first aspect, which is a polypropylene resin comprising 0 to 80% by weight of a propylene copolymer containing 10 to 80% by weight of an olefin unit other than propylene. (3) The multilayer sheet according to the above 1 or 2, wherein the non-woven fabric is formed by spot fusion using a filament made of isotactic polypropylene. (Fourth) A method for producing a multilayer sheet, in which a propylene-based thermoplastic elastomer sheet is heated to a temperature below its melting point and pressure-laminated on at least one surface of a non-woven fabric made of isotactic polypropylene fibers. (Fifth) The method for producing a multilayer sheet according to the fourth aspect, wherein pressure lamination under heating is performed using a heating press using an endless belt. (Sixth) The method for producing a multilayer sheet according to the fifth aspect, wherein the pressure lamination under heating is performed using a heating press machine in which at least one of the roll and the endless belt is under heating. (Seventh) The method for producing a multilayer sheet according to the fifth embodiment, wherein the pressure lamination under heating is performed by using at least a pair of belt type presses in which at least one endless belt is under heating.

The contents of the present invention will be described in detail below. The isotactic polypropylene fiber, which is the raw material of the nonwoven fabric according to the present invention, is not limited by the value of isotacticity, but the melting point or heat distortion temperature is the propylene-based thermoplastic used for lamination to the nonwoven fabric. Higher than elastomer is used. Also, the form of the fibers is not particularly limited, and may be any form of fibers conventionally used for nonwoven fabrics. Commonly used materials include filaments for weaving, staple fibers for spinning or papermaking, split fibers, fine denier monofilaments and the like. Whether or not the fiber itself is drawn is not particularly limited, but in the case of split fiber, it is obtained as a result of the drawing process and is itself a drawn fiber.

The non-woven fabric according to the present invention is a sheet-like non-woven fabric using the above isotactic polypropylene fiber, and the conventional production method can be applied as it is. However, in order to apply the production method according to the present invention, Is required to flow the propylene-based thermoplastic elastomer under heat and pressure at a temperature lower than its melting point so that it flows between the fibers of the non-woven fabric to be entangled with the fibers. It is difficult to obtain high quality products. However, a non-woven fabric having a low fixation between fibers is not preferable because not only a multi-layered sheet having high mechanical strength cannot be obtained, but also it becomes difficult to maintain its shape under the multi-layered sheet manufacturing conditions. Although these requirements are contradictory, the fixation between fibers is entangled (entangled) between the fibers.
Is most preferable. Other methods for fixing the fibers include point fusion with a heating element, point adhesion with an adhesive, and point pressure sealing during melt spinning.

The propylene-based thermoplastic elastomer according to the present invention is a propylene-based polymer having a low degree of crystallinity, which does not exhibit elasticity at room temperature, but exhibits the properties of an elastomer when heated, and is usually ethylene or even butene. It is a propylene-based copolymer containing an olefin such as 1 as a copolymerization component, and a so-called non-crosslinked one is used because it is required to have fluidity such that it is thermocompression-bonded and flows between fibers of a nonwoven fabric.

A suitable propylene-based thermoplastic elastomer used in the present invention is a propylene-based thermoplastic elastomer having a pentad fraction of (a) (a) isotope carbon nuclear magnetic resonance spectrum ( ¹³ C-NMR). , Rrrr / (1-mmmm) × 100 is 20 to 60
%, (B) the melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) is 150 ° C. or higher, and (c) DS
Melting enthalpy (ΔH) measured at C is 100 J /
Homopolymer of propylene which is less than or equal to g and / or copolymer 100 containing less than 4% by weight of other olefin units.
To 20% by weight and (b) 10 to 80% by weight of an olefin unit other than propylene, a propylene-based copolymer 0
It is a polypropylene resin composed of ˜80% by weight.
It is particularly preferred that the polypropylene resin is mixed with an aliphatic monocarboxylic acid metal salt in terms of reduction of thickness unevenness during production of a multilayer sheet, improvement in appearance and heat resistance, and imparting flexibility to the multilayer sheet.

The above-mentioned suitable propylene-based thermoplastic elastomer is (a) pentad fraction based on isotope carbon nuclear magnetic resonance spectrum ( ¹³ C-NMR), and rr
It is necessary that rr / (1-mmmm) × 100 is in the range of 20 to 60%. If this value is less than 20%, the heat resistance is insufficient, and if it exceeds 60%, the flexibility is insufficient. From these aspects, preferable rrrr / (1-
mmmm) × 100 is in the range of 25 to 55%. Here, rrrr is a three-dimensional structure in which five methyl groups, which are side chains, are alternately located in opposite directions with respect to the main chain formed by carbon-carbon bonds composed of arbitrary continuous five propylene units, or a ratio thereof. The term "mmmm" means a three-dimensional structure in which all five methyl groups as side chains are located in the same direction with respect to the main chain formed by carbon-carbon bonds composed of arbitrary continuous five propylene units, or the ratio thereof. Means Note that this rrrr / (1-mmmm) × 100
Is a value measured as follows. That is, JNM
-FX-200 (manufactured by JEOL Ltd., ¹³ C-nuclear resonance frequency 5
0.1 MHz), measurement mode: complete proton decoupling method, pulse width: 6.9 μs (45 °), pulse repetition time: 3 s, integration number: 10000 times, solvent:
1,2,4-trichlorobenzene / heavy benzene (90 /
10% by volume), sample concentration 250 mg / 2.5 ml solvent, measurement temperature: 130 ° C., ¹³ C-NMR measurement is performed, and due to difference in chemical shift due to stereoregularity of methyl group, that is, 22. The pentad fraction was measured from the area intensity ratio of each peak of mmmm to mrrm appearing in the 5 to 19.5 ppm region, and rrrr / (1-mmm
The value of m) × 100 was determined. mmmm: 21.86 ppm mmmr: 21.62 ppm mmrr: 21.08 ppm mmrm + rrmr: 20.89 ppm rrrr: 20.36 ppm mrrm: 19.97 ppm

Next, (b) a differential scanning calorimeter (DS)
It is necessary that the melting peak temperature (Tm) measured in C) is 150 ° C. or higher. If Tm is less than 150 ° C, sufficient heat resistance cannot be obtained. This Tm is usually 150-1
It is in the range of 65 ° C. The Tm is Perkin-
Measurement was performed using DSC-7 manufactured by Elmer, and JIS
It is the value obtained as the temperature of the melting peak according to K-7121.

Further, (c) it is necessary that the enthalpy of fusion (ΔH) measured by DSC is 100 J / g or less. When ΔH exceeds 100 J / g, flexibility is impaired and the object of the present invention cannot be achieved. This ΔH is usually 2
It is in the range of 0 to 100 J / g. The ΔH is Pe
It is a value obtained by performing measurement using DSC-7 manufactured by rkin-Elmer, and as the total heat energy absorbed during crystal melting in accordance with JIS K-7122.

The propylene homopolymer as the component (a) and the copolymer containing 4% by weight or less of other olefin units have a boiling n-heptane-soluble content of 30 to 95.
Those in the range of weight% are preferred. If the boiling n-heptane-soluble content is less than 30% by weight, flexibility may be impaired, and if it exceeds 95% by weight, sufficient mechanical strength may not be obtained. From the viewpoint of the balance between flexibility and mechanical strength, the more preferable boiling n-heptane-soluble content is in the range of 40 to 90% by weight. The boiling n-heptane soluble content is a value obtained by calculating the soluble content from the extraction residual quantity after extraction with boiling n-heptane for 6 hours using a Soxhlet extraction tester. Further, in the propylene homopolymer and the copolymer containing 4% by weight or less of other olefin units, carbon having a methyl group on the side chain is usually not adjacently arranged in the propylene chain part. , That is, there is no reverse coupling, and every other line is neatly arranged. That is, in the present invention, each propylene unit is linked by a head-tail bond, and there is substantially no head-head bond or tail-tail bond. Is.

In the propylene copolymer containing 4% by weight or less of the other olefin units, examples of the olefins of the comonomer forming the other olefin units include ethylene; butene-1; pentene-1; Four
-Methyl-1-pentene; hexene-1; heptene-
1; octene-1, nonene-1, decene-1 and other α-
Olefins can be mentioned. Of these, ethylene is preferred. These olefins may be used alone or in combination of two or more. Further, it is necessary to use the olefins of these comonomers such that the content of the units derived from the olefins in the obtained propylene copolymer is 4% by weight or less.

As the aliphatic monocarboxylic acid metal salt to be blended with the polypropylene resin, a metal salt of a saturated or unsaturated monocarboxylic acid having 8 to 32 carbon atoms, and as the metal, Na, K, Cu, Mg, Zn, Al, Co and the like are particularly suitable.

In the method for producing a multilayer sheet according to the present invention, a nonwoven fabric made of fibers made of isotactic polypropylene resin is not brought into a molten state, while the propylene thermoplastic elastomer is preformed into a sheet. A method is used in which the material is used in a molten state without heating until it is in a molten state and is pressure-laminated, but a roll / belt or a belt / belt combination is preferable as a laminating means. In the above production method, at least the latter of the non-woven fabric and the propylene-based thermoplastic resin elastomer is heated, it is necessary to make it in a fluid state, but it is also possible to use a method of pressure lamination while heating with a roll or a belt, The method of pressurizing or heating and pressurizing while preheating one or both is also preferably adopted. The propylene-based thermoplastic resin elastomer is laminated on at least one surface of the nonwoven fabric, and when laminated on both surfaces of the nonwoven fabric, the propylene-based thermoplastic resin elastomers of both outer layers are preferably laminated under the same conditions. By applying the heating and pressurizing lamination condition to the nonwoven fabric on the roll side, it is possible to obtain a waterproof sheet having not only thickness unevenness but also excellent flexibility, surface hardness (feeling without stickiness) and impact characteristics.

An example will be described below. (Embodiment) Double belt type laminating apparatus 1 shown in FIG.
And non-woven fabric 3a with a thickness of 0.39 mm and a basis weight of 50 g / m ² .
("Idemitsu Petrochemical Co., Ltd.""Idemitsu Stratec RW205
0 ", a continuous continuous fiber nonwoven fabric made of polypropylene by the spunbond method. ) As an intermediate layer, and a 0.2 mm-thick propylene thermoplastic elastomer molded by the T-die method on both sides (“Idemitsu TPOE-260 manufactured by Idemitsu Petrochemical Co., Ltd.”).
0 ") sheets 4a and 5a were laminated to form a multilayer sheet. The molding conditions are as follows: each sheet of thermoplastic elastomer is pulled out from rolls 4 and 5, and both sides are heated by heaters 7 and 8.
Guide roller 1 while controlling in the range of 00 to 155 ° C
After heating the both sides of the non-woven fabric 3a pulled out from the non-woven fabric roll 3 with the heater 6 in the range of 80 to 150 ° C., it is sent to the double belt 2 and the range of 120 to 150 ° C. Between the endless belts 2a and 2b having the surface temperature controlled in 1., the layers are continuously laminated under a pressure of 1.47 MPa (using the heating and pressurizing devices 2c and 2d) and then cooled to obtain a multilayer of 0.45 mm in thickness. Sheet 9 was obtained. When the flexibility, surface hardness, and mechanical properties were compared with the conventional PVC-based sheet waterproof material, it was found to be excellent as follows. (1) Surface hardness (Shore hardness, JIS K7215) Multilayer sheet of the present invention ... 56D, PVC-based sheet ... 3
0D (2) Breaking strength (JIS K7113) Multilayer sheet of the present invention ... 120 MPa, PVC sheet ... 27 MPa

[0021]

EFFECTS OF THE INVENTION By placing a non-woven fabric made of isotactic polypropylene fibers on one side or an intermediate layer and laminating a propylene-based thermoplastic elastomer on the other side or both sides in a fluid state below its melting point, it is more flexible than before. It was possible to obtain a waterproof sheet having excellent surface hardness and mechanical properties.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a process of producing a propylene-based thermoplastic elastomer on both sides of a nonwoven fabric by a double belt method.

[Explanation of symbols]

1 ······················································································· Heating / pressurizing device 3 ・ ・ ・ ・ ・ ・ Nonwoven fabric roll 3a ・ ・ ・ ・ ・ Nonwoven fabric 4,5 ・ ・ ・ ・ ・ ・ Propylene-based thermoplastic elastomer sheet roll 4a, 5a ・・ ・ ・ Propylene-based thermoplastic elastomer sheet 6,7,8 ・ ・ ・ ・ Double-sided heater 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Multilayer sheet 10,11 ・ ・ ・ ・ ・ ・ Guide roll

Claims (7)

[Claims] 1. A multi-layer sheet in which a layer of a propylene-based thermoplastic elastomer is laminated on at least one side of a non-woven fabric made of isotactic polypropylene fibers. 2. A propylene-based thermoplastic elastomer comprising (a) (a) isotope carbon nuclear magnetic resonance spectrum ( ¹³ C-
Pentad fraction by NMR), rrrr /
(1-mmmm) × 100 is 20 to 60%, (b) the melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) is 150 ° C. or higher, and (c) the melting enthalpy measured by DSC ( [Delta] H) 100 to 20% by weight of a propylene homopolymer having 100 J / g or less and / or a copolymer containing 4% by weight or less of another olefin unit.
And (b) 10 to 80 olefin units other than propylene
Propylene copolymer containing 0 to 80% by weight
The multilayer sheet according to claim 1, which is a polypropylene-based resin consisting of 3. The multilayer sheet according to claim 1 or 2, wherein the non-woven fabric is formed by entanglement of filaments made of isotactic polypropylene. 4. A method for producing a multilayer sheet, comprising heating a propylene-based thermoplastic elastomer sheet to a temperature below its melting point and laminating under pressure on at least one surface of a non-woven fabric made of isotactic polypropylene fibers. . 5. The method for producing a multilayer sheet according to claim 4, wherein the pressure-laminating under heating is carried out by using a heating press using an endless belt. 6. The method for producing a multilayer sheet according to claim 5, wherein the pressure lamination under heating is performed by using a heating press machine in which at least one of the roll and the endless belt is under heating. 7. The method for producing a multilayer sheet according to claim 5, wherein the pressure-laminating under heating is carried out by using at least a pair of belt type presses in which at least one endless belt is under heating.