JP2000319455A - Water barrier sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water barrier sheet having flexibility enough to follow the contour of ground, being easily bondable with other sheets to give a bonded sheet having joints with good bonding force by using a composition prepared by mixing a thermoplastic olefin elastomer with a crystalline polyolefin produced by using a metallocene catalyst. SOLUTION: This sheet has a tensile strength at break of at least 300 kgf/cm2 and a tensile elongation at break of at least 650%. It can attain an initial modulus of below 1,000 kgf/cm2, a bonding strength of at least 45 kgf/25 mm, and a bonding rate of at least 1.7 m/min. It is desirable that the crystalline polyolefin used is one obtained by copolymerizing ethylene with a 3-20C α-olefin and having a density of 0.89-0.91 g/cm3 and a melt index of 0.1-20 g/10 min. The mixing ratio is desirably such that the thermoplastic elastomer accounts for at least 20 wt.%, the crystalline polyolefin accounts for at least 40 wt.%, and the total of both accounts for at least 75 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-shielding sheet formed from a thermoplastic elastomer composition, and more particularly, to a light-shielding sheet having dramatically improved flexibility, tensile strength and heat-fusibility as compared with conventional products. Water sheet.

[0002]

2. Description of the Related Art Water-blocking sheets used for water-blocking works in civil engineering works at various construction sites and the like are formed of a composition mainly composed of vulcanized rubber or a thermoplastic elastomer composition. There are things.

[0003] Of these, thermoplastic elastomers are:
It is widely used in various industrial products as a material having properties in the intermediate range between rubber and plastic, or as a substitute for rubber.

[0004] Usually, a plurality of water-impervious sheets are joined together to form a large integral water-impervious film during use. However, in a conventional water-impervious sheet formed from a thermoplastic elastomer composition, There were problems in terms of adhesive strength and weather resistance. In order to solve such a problem, there has been proposed a sheet formed by blending a predetermined amount of an ethylene polymer or a crystalline polyolefin with a thermoplastic elastomer (Japanese Patent Application Laid-Open Nos. 59-18741 and 59-18741). -106137
No.).

[0005]

However, in the conventionally proposed water-blocking sheet, although the joining workability has been improved by heat fusion, it is harder than vulcanized rubber and has poor followability to the ground. However, there was still difficulty in the workability of the construction.
In addition, there is a need to improve the adhesive strength of the joining portion and the speed at the time of joining the water impermeable sheets. Furthermore, although the toughness of the water-blocking sheet body has been improved compared to vulcanized rubber, a further dramatic improvement was necessary to ensure the safety and reliability of the water-blocking film. .

Accordingly, an object of the present invention is to solve all of the above-mentioned problems, to provide flexibility with excellent ground-following properties, to easily join the water-impervious sheets, and to obtain a good bond between the joints. It is an object of the present invention to provide a waterproof sheet having strength, toughness and high reliability.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that an olefin-based thermoplastic elastomer and an ethylene-α-olefin copolymer produced using a specific catalyst In the thermoplastic elastomer containing, the physical property values such as tensile rupture strength and tensile rupture elongation are greatly improved as compared with the conventional, as a result, mechanical strength, flexibility and heat fusion properties are also significantly improved, The inventors have found that the object can be achieved, and have completed the present invention. That is, the present invention is as described below.

(1) a thermoplastic elastomer containing an olefin-based thermoplastic elastomer and a crystalline polyolefin produced using a metallocene-based catalyst,
A water-blocking sheet characterized by having a tensile strength at break of 300 kgf / cm ² or more and a tensile strength at break of 650% or more.

(2) The water-impervious sheet, wherein the initial elastic modulus is less than 1000 kgf / cm ² .

(3) In the waterproof sheet, the bonding strength is 45 kgf / 25 mm or more, and the bonding speed is 1.7.
m / min or more.

(4) In the waterproof sheet, the density of the crystalline polyolefin produced by using the metallocene catalyst is 0.89 to 0.91 g / cm ³ and the melt index is 0.1 to 20 g / cm ^3. It is a water-impervious sheet that lasts 10 minutes.

(5) In the water-shielding sheet, the crystalline polyolefin produced by using the metallocene catalyst is obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms with a metallocene catalyst. It is a waterproof sheet made of crystalline polyethylene.

(6) In the waterproof sheet, the olefin-based thermoplastic elastomer contains at least 20% by weight.
And at least 40% by weight or more of a crystalline polyolefin produced using the metallocene-based catalyst,
The water-impervious sheet has a total of 75% by weight or more.

According to the above (1), the mechanical strength is improved, and the safety and reliability of the water barrier film are improved.

According to the above (2), the flexibility is improved in addition to the above-mentioned effects, the ability to follow the ground is enhanced, and the workability is improved.

According to the above (3), in addition to the above-mentioned effects, the heat fusing property is also improved, and the bonding strength of the bonding portion and the bonding speed between the water shielding sheets are improved.

[0017] By the above (4) to (6), the above-mentioned action is satisfactorily exhibited, and has unprecedented mechanical strength and flexibility.
A water-blocking sheet having significantly improved heat-fusibility can be obtained. That is, in the water-barrier sheet of the present invention, water-blocking is performed by using a thermoplastic elastomer composition obtained by mixing an olefin-based thermoplastic elastomer and a crystalline polyolefin produced using a metallocene-based catalyst with an inorganic filler as appropriate. As a result of the formation of the sheet, a waterproof sheet having not only the flexibility of the olefin-based thermoplastic elastomer but also the heat resistance, mechanical strength, and the like of the crystalline polyolefin produced using the metallocene-based catalyst is obtained.

[0018]

Embodiments of the present invention will be described below. First, each component of the thermoplastic elastomer composition which is a raw material of the water barrier sheet of the present invention will be described.

The olefin-based thermoplastic elastomer used in the present invention is obtained by dynamically heat-treating an olefin-based copolymer rubber and a polyolefin to partially crosslink.

The olefin-based copolymer rubber used for producing the olefin-based thermoplastic elastomer includes two or more kinds of α-olefins such as ethylene, propylene, 1-butene, 1-hexene and 4-methyl-pentene. Copolymer rubber. Such a copolymer rubber is typically an ethylene-butene copolymer rubber (EB
R), ethylene-propylene copolymer rubber (EPR),
And ethylene-propylene-diene copolymer rubber (E
PDM) and the like. As the diene in the ethylene-propylene-diene copolymer rubber (EPDM), a non-conjugated diene such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene or a conjugated diene such as butadiene or isoprene is used. be able to.

The content of ethylene in the olefin copolymer rubber is 20 to 90% by weight, preferably 35 to 80% by weight. When the content of ethylene is less than 20% by weight or more than 90% by weight, it becomes difficult to exhibit properties as an elastomer. The iodine value (degree of unsaturation) is 30 or less, and the Mooney viscosity ML
_{1 + 3} (127 ° C.) is preferably in the range of 5 to 300. The crystallinity of such an olefin-based copolymer rubber is usually 40% by weight or less.

Next, polyolefins that can be used in the production of olefin-based thermoplastic elastomers include:
Isotactic polypropylene, propylene and other α
Copolymers with olefins, for example, propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1-pentene copolymers, and the like. be able to.

An olefin-based thermoplastic elastomer is produced from the above-mentioned olefin-based copolymer rubber and polyolefin. In addition to the above-mentioned two components, a mineral oil-based softener is appropriately added, and partially crosslinked with an organic peroxide. To obtain an elastomer having appropriate flexibility.

When an olefin-based elastomer is prepared by using an olefin-based copolymer rubber, polypropylene, and a mineral oil-based softener, the amount of the olefin-based elastomer is preferably as follows. That is, with respect to 100 parts by weight of the olefin-based copolymer rubber, 20 to 40 parts by weight of polypropylene and 5 to 150 parts by weight of a mineral oil-based softener are mixed.

The organic peroxide is added in an amount of 0.01 to 3 parts by weight, preferably 0.01 to 0.3 parts by weight, based on 100 parts by weight of each of the above components.

Such an olefin-based thermoplastic elastomer has a degree of crosslinking of 30 to 90% (percentage of the whole elastomer composition) and a hardness of 50 to JIS A.
It is desirable to be 95 °.

The olefin-based thermoplastic elastomer can be produced by mixing the above-mentioned components and dynamically heat-treating, that is, melt-kneading. As the kneading apparatus, conventionally known ones such as a non-open type Banbury mixer, an extruder (including a twin screw), a kneader, and a continuous mixer can be used. Among these, it is preferable to use a non-open type device,
The kneading is preferably performed in an atmosphere of an inert gas such as nitrogen or carbon dioxide. The kneading temperature is appropriately set according to the melting point of the polyolefin. The kneading time is 1 to 30 minutes, preferably 5 to 10 minutes.

Next, the crystalline polyolefin produced by using a metallocene-based catalyst which can be used in the present invention may be, for example, a transition metal such as zirconium, hafnium, or titanium having at least one cyclopentadienyl group or a substituted metal. Using a metallocene catalyst having a cyclopentadienyl group, ethylene and preferably 3 to 20 carbon atoms, more preferably 3 to 8 carbon atoms, and still more preferably 3 to 3 carbon atoms.
And can be produced by copolymerizing α-olefin No. 6 with an α-olefin.

Α which is preferably used for copolymerization with ethylene
-As olefins, propylene, 1-butene, 4-
Methyl-1-pentene, 1-pentene, 1-hexene,
Examples thereof include 1-octene and 1-decene, and one or more of these can be used for copolymerization with ethylene. The crystalline polyolefin (ethylene-α-olefin copolymer) that can be used in the present invention may be a single type or a blend of two or more types, and furthermore, a range in which there is no problem in processability, heat resistance, and mechanical strength. It is also possible to blend another thermoplastic resin such as an ethylene polymer.

The density of such a crystalline polyolefin is
Preferably 0.89 to 0.91 g / cm ³ ,
The melt index (190 ° C., 2.16 kg load) specified in JIS K6760 is 0.1 to 20 g /
10 minutes, preferably 0.5 to 10 g / 10 minutes.

When the density is less than 0.89 g / cm ³ , physical properties such as tear strength and heat resistance of the sheet are significantly reduced. On the other hand, when the density exceeds 0.91 g / cm ³ ,
This is not preferable because the flexibility of the sheet is deteriorated.

Further, the melt index is 0.1 g.
If the time is less than / 10 minutes, the sheet formability deteriorates.
Not preferred. On the other hand, the melt index is 20 g / 1
If the time exceeds 0 minutes, the kneading property with the olefin-based thermoplastic elastomer deteriorates, which is also not preferable.

In the water-shielding sheet of the present invention, the tensile rupture strength is 300 kgf / cm by mixing the olefin-based thermoplastic elastomer and the crystalline polyolefin.
^A tensile elongation at break of at least ² and a tensile elongation at break of 650% or more can be realized, and the initial elastic modulus can be reduced to less than 1000 kgf / cm ² . Furthermore, the joining strength is 45 kgf
/ 25 mm or more, and a joining speed of 1.7 m / min or more. As a result, the mechanical strength, flexibility, and heat-fusibility of the obtained thermoplastic elastomer composition are dramatically improved, and the processability is also stabilized.

In the present invention, in addition to the above two components,
Inorganic fillers, pigments, various stabilizers, and the like can be added. First, preferably, the olefin-based thermoplastic elastomer contains at least 20% by weight or more and the crystalline polyolefin produced by using the metallocene-based catalyst at least 40% by weight or more.
% By weight or more, preferably 80% by weight or more. If the olefin-based thermoplastic elastomer is less than 20% by weight, the initial elastic modulus of the water-shielding sheet is increased, and the flexibility is undesirably reduced. On the other hand, if the amount of the crystalline polyolefin is less than 40% by weight, the bonding strength between the water-impermeable sheets and the strength are reduced, which is not preferable.

An inorganic filler which can be added in the present invention,
The amount of the pigment, stabilizer and the like is preferably 25% by weight or less, more preferably 20% by weight or less. If the amount of the inorganic filler exceeds 25% by weight, the flexibility and strength of the obtained sheet will decrease.

The preparation of the thermoplastic elastomer composition as a sheet forming material is carried out by mixing the above-mentioned components and mixing the mixture with a conventional material such as a Banbury mixer, a single or twin screw extruder, a mixing roll, a kneader, or a continuous mixer. Using a kneading apparatus, 150 to 250 ° C., preferably 1 to 250 ° C.
Kneading is performed at 50 to 200 ° C. for about 1 to 10 minutes. This kneading is preferably performed in an atmosphere of an inert gas such as nitrogen gas or carbon dioxide gas, similarly to the kneading at the time of producing the above-mentioned olefin-based thermoplastic elastomer.

The order of mixing the components (the order of mixing) is not particularly limited, and may be set as appropriate according to the materials used.

For the formation of a water-barrier sheet comprising the thermoplastic elastomer composition obtained by such a method, a usual sheet forming method can be employed as it is. That is, 150
By extruding the molten mixture from the T-die at a temperature of about 250 ° C., a sheet having a thickness of about 0.5 to 3.0 mm can be easily formed. Further, the thermoplastic elastomer composition heated to a temperature higher than the softening point can be formed into a sheet by a calender roll or the like.

[0039]

The present invention will be described in more detail with reference to the following examples. First, the method for preparing the olefin-based thermoplastic elastomer used in each of the examples and comparative examples and other components will be described. Preparation of olefin-based thermoplastic elastomer (I) Thermoplastic elastomer (a) 20 parts by weight of propylene-ethylene (hereinafter abbreviated as “PP”) (melt index at 230 ° C. under a load of 2.16 kg: 10 g / 10 min) And (ii) an ethylene-propylene-diene copolymer rubber (hereinafter referred to as “EPD
M ”) (Mooney viscosity ML at 121 ° C .: 5)
5, ethylene content: 79% by weight, diene component: ethylidene norbornene, iodine value: 10) 80 parts by weight,
(C) 5 parts by weight of a softening agent (paraffin-based process oil) are mixed, and (d) peroxide (2,5-
Dimethyl-2,5-di (t-butylperoxy) hexyne-3) is added in an amount of 0.2 part by weight based on 100 parts by weight of the total of (a) to (c), and the mixture is added at 3 to 5 at 175 ° C. The mixture was partially kneaded and partially crosslinked to obtain (I) a thermoplastic elastomer. This (I) thermoplastic elastomer has a degree of cross-linking (a value calculated from xylene-insoluble matter) of 60%.
The hardness according to A was 80 °.

(II) Thermoplastic elastomer (a) 15 parts by weight of a random copolymer resin of propylene and ethylene (hereinafter abbreviated as “R-PP”);
Oil-extended EPDM (ML (1
00 ° C.): 50, ethylene content: 68% by weight) and 85 parts by weight.
(C) The above peroxide was added in an amount of 0.04 part by weight, and partially crosslinked by heating and kneading to obtain (II) a thermoplastic elastomer. This thermoplastic elastomer (II) had a degree of crosslinking (a value calculated from xylene-insoluble components) of 50% and a hardness according to JIS A of 53 °.

Crystals produced using metallocene catalysts
Polyolefin (I) LLDPE: linear low density polyethylene (melt index: 2.0 g / 10 min, density: 0.895 g)
/ Cm ³ ). (II) LLDPE: linear low density polyethylene (melt index: 4.0 g / 10 min, density: 0.905 g)
/ Cm ³ ).

Heavy calcium carbonate, carbon black, hindered phenol-based heat stabilizers, hindered amine-based light stabilizers and the like were used such as inorganic fillers, pigments and various stabilizers .

Examples 1 to 5 The respective components were blended in the proportions shown in Table 1 below and melt-kneaded at a cylinder temperature of 210 ° C. using a twin-screw kneading extruder to obtain a pellet-shaped kneaded product.

The obtained pellets were formed into a sheet by a sheet forming machine to obtain a sample. The following tests were performed on each sample. The test method is as follows. (1) Tensile breaking strength (kgf / cm ² ): JIS K6
No. 3 dumbbell, pulling speed 500m according to 310
It was measured at m / min. (2) Tensile elongation at break (%): Measured according to JIS K6310. (3) Hardness: The result of measurement with a JIS A hardness meter was shown. (4) Flexibility: The following criteria were used to evaluate the difference in the initial tensile modulus (kgf / cm ² ). Tensile modulus (kgf / cm ² ) ○: less than 1000 △: 1,000 or more to less than 1500 ×: 1500 or more (5) Bonding force: A sample was thermally fused using an automatic thermal fusion machine, and peeling at a width of 25 mm was performed. The strength (kgf / 25 mm) was measured. (6) Bonding speed: The sample was heat-sealed at a plurality of welding speeds using an automatic heat-sealing machine while keeping the temperature and pressure constant. Thereafter, the fusion speed at which the joint began to break the body was determined. The results obtained are shown in Table 1 below.

Comparative Examples 1 to 3 For comparison, sheets were prepared for those having too little olefin-based thermoplastic elastomer (Comparative Example 1) and those having too much olefin-based thermoplastic elastomer (Comparative Example 2). Various tests were performed in the same manner as in Example 1. Further, a conventional product (Comparative Example 3) was also compared under the same conditions. The results obtained are shown in Table 1 below.

[0046]

[Table 1]

[0047]

[Table 2] Degree of crosslinking (xylene-insoluble): 60%, hardness according to JIS A: 80 ° Degree of crosslinking (xylene-insoluble): 50%, hardness according to JIS A: 53 ° Density: 0.895 g / cm ³ , melt index:
2.0 g / 10 min Density: 0.905 g / cm ³ , Melt index:
4.0 g / 10 minutes

As is clear from Table 1, the water impermeable sheet of the present invention has high tensile strength and stable elongation. Also, the flexibility is good, the bonding strength between the sheets is high, and the bonding speed is high.

On the other hand, in Comparative Example 1, the amount of the thermoplastic elastomer was small, the amount of the filler was large, and the hardness was apparently hardened, and the tensile rupture strength and the joining strength were in the decreasing direction. In Comparative Example 2, since a large amount of the thermoplastic elastomer was blended, the tensile strength at break was reduced and the bonding strength was also reduced. Furthermore, Comparative Example 3 is a conventional product, and it is clear from the results that the products of the present invention of Examples 1 to 5 are dramatically improved in all of the flexibility, toughness and bondability.

[0050]

As described above, the impermeable sheet of the present invention is a sheet that is rich in flexibility, has good ground following properties, has very high mechanical strength, is tough, and is not easily damaged. In addition, since the joining strength is high and the joining speed is high, the workability is good, and the reliability as a water barrier film is greatly improved.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) E02B 3/12 E02B 3/12 F term (Reference) 2D018 DA03 4F071 AA10 AA14 AA15X AA20X AA21X AA82 AA88 AF11 AF15Y AF19Y AF20Y AF21Y AF26 AF59 AH03 AH19 BA01 BB06 BC01 4J002 BB00W BB05W BB05X BB12X BB14X BB15X BB16X BB20X BP02X FD020 FD150 GA01 GC00 GG00

Claims (6)

[Claims] 1. An olefinic thermoplastic elastomer,
A shielding material comprising a thermoplastic elastomer containing a crystalline polyolefin produced by using a metallocene catalyst and having a tensile strength at break of 300 kgf / cm ² or more and a tensile elongation at break of 650% or more. Water sheet. 2. The impermeable sheet according to claim 1, wherein the initial elastic modulus is less than 1000 kgf / cm ² . 3. The waterproof sheet according to claim 1, wherein the bonding strength is 45 kgf / 25 mm or more, and the bonding speed is 1.7 m / min or more. 4. The crystalline polyolefin produced using the metallocene catalyst has a density of 0.89 to 0.91 g.
/ Cm ³ and the melt index is 0.1 to 20 g
The water impermeable sheet according to any one of claims 1 to 3, which is / 10 minutes. 5. The crystalline polyolefin produced using the metallocene-based catalyst comprises ethylene and C3 to C20.
The water-impermeable sheet according to any one of claims 1 to 4, which is a crystalline polyethylene obtained by copolymerizing an α-olefin with a metallocene catalyst. 6. At least 20% by weight or more of the olefin-based thermoplastic elastomer and at least 40% by weight or more of a crystalline polyolefin produced by using the metallocene-based catalyst, and the total of both is 75% by weight.
The water impermeable sheet according to any one of claims 1 to 5, which is as described above.