JPH11140248A - Thermoplastic elastomer composition and sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyethylene-or an α-olefin-ethylene copolymer-containing thermoplastic elastomer composition good in adhesion to a high-density polyethylene(HDPE) by thermal fusion and having a high strength at high temperatures. SOLUTION: This composition comprises a polyethylene and an α-olefin- ethylene copolymer having <=4.0 Mw /Mn and >=0.91 (g/cm<3> ) density in an amount of 5-100 pts.wt. based on 100 pts.wt. of a thermoplastic elastomer containing an ethylene-propylene copolymer rubber (EPDM) and a polypropylene-based resin (PP) at (30/70) to (70/30) weight ratio of EPDM to PP therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition containing polyethylene or α-olefin-ethylene copolymer, which has good adhesion to HDPE by thermal fusion and has high material strength at high temperatures, and uses the same. Regarding the sheet.

[0002]

2. Description of the Related Art As a material used for a waterproof sheet used in a waste disposal site and a waterproof sheet used in a tunnel construction method, and a waterproof sheet used in a roofing material for construction, etc. Vulcanized rubber compositions based on propylene / diene copolymer rubber (EPDM) are excellent in flexibility and weather resistance, but have disadvantages such as insufficient mechanical strength and heat fusion. On the other hand, resin materials, such as high-density polyethylene (HPDM), which are often used, have high breaking strength, but lack flexibility and have a heat-fusing property, but are hard even when heated. There were drawbacks that they were difficult to fuse and were inferior in workability. In contrast, in recent years, polypropylene-based resins (PP)
Attention has been focused on a heat-sealable flexible sheet using a thermoplastic elastomer composition comprising a rubber composition and a dynamically vulcanized rubber composition. However, the sheet most widely used in the sheet waterproofing method is a sheet made of high-density polyethylene (HDPE), and thus other sheets used in the sheet waterproofing method can be bonded to HDPE, particularly, heat-sealed. Preferably it is. Among such sheets, P is used as a sheet having flexibility that can be used on an uneven surface.
JP-A-59-18741 and JP-A-2-255733 disclose a sheet in which an ethylene copolymer is blended with a thermoplastic elastomer composed of P / EPDM.
Publication), since ethylene copolymers usually have a low melting point,
The sheet containing it also has the disadvantage that the strength at high temperatures is not sufficient, such as when the sheet is left in the hot sun.

[0003]

SUMMARY OF THE INVENTION The present invention provides a thermoplastic elastomer composition containing polyethylene or α-olefin-ethylene copolymer, which has good adhesion to HDPE and high strength at high temperatures, and a sheet using the same. try to.

[0004]

That is, an object of the present invention is to provide an EPDM / PP having an EPDM / PP (weight ratio) of 30.
/ 70-70 / 30 thermoplastic elastomer 100
Mw / Mn ≦ 4.0 and density 0.91 to parts by weight
(G / cm < ³ >) The present invention provides a thermoplastic elastomer composition containing 5 to 100 parts by weight of a polyethylene or an α-olefin-ethylene copolymer. Among them, it is preferable that the polyethylene or the α-olefin-ethylene copolymer is polymerized using a metallocene catalyst. Further, the present invention provides a waterproof sheet comprising the above-mentioned thermoplastic elastomer composition.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic elastomer used in the present invention contains EPDM and PP at a weight ratio of 30/70 to 70/30 of EPDM / PP. EPDM in the present invention is a rubber composed of ethylene, propylene and a diene monomer. Further, an ethylene-propylene copolymer rubber (EPM) having no diene component can be similarly used. Examples of the diene monomer include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, and cyclooctadiene. Of these, ethylidene norbornene having a high vulcanization rate is preferred. The amount of the third component is 3 to 2 in iodine value.
5 and more preferably about 5 to 20. Of these, E
The PDM preferably has a propylene content of 10 to 70 mol%.

[0006] The PP in the present invention may have any stereochemical structure of isotactic, syndiotactic and atactic having propylene as a unit. Other examples include copolymers containing propylene as a main component and a small amount of another monomer copolymerizable therewith. Other monomers that can be copolymerized include ethylene, 1-butene, 1-pentene, 1-hexene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-
Methyl-1-pentene, 5-methyl-1-hexene and the like. Among them, those having a heat deformation temperature of 100 ° C. or more according to JIS K7207 are preferable. EPDM and PP in the thermoplastic elastomer are in a weight ratio (EP
DM / PP) is 30/70 to 70/30, preferably 50/50 to 70/30. If the amount of PP is too large, the flexibility of the obtained thermoplastic elastomer is impaired, and if the amount is too small, the fluidity becomes insufficient.

[0007] The thermoplastic elastomer composition of the present invention further comprises a crosslinking agent such as a crosslinking agent, a crosslinking accelerator, a crosslinking aid, and the like.
M, PP are melt-kneaded by a twin-screw kneading extruder or the like, uncrosslinked EPDM is dispersed in PP forming a matrix, a crosslinking agent is added under kneading, and the uncrosslinked EPDM is kneaded.
It has a configuration in which it is dynamically vulcanized, PP is used as a matrix, EPDM is dispersed as a dispersed phase (domain), and at least a part of EPDM is crosslinked.

As the crosslinking agent used in the present invention, a sulfur-based crosslinking agent, an organic peroxide-based crosslinking agent, a phenol-based crosslinking agent, and the like can be used. Specifically, examples of the sulfur-based cross-linking agent include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, and alkylphenol disulfide, and for example, 0.5 to 4 phr. (Parts by weight per 100 parts by weight of polymer in EPDM) may be used. As the organic peroxide-based crosslinking agent, benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexane, 2,5
-Dimethylhexane-2,5-di (peroxyl benzoate) and the like are exemplified, and for example, about 1 to 15 phr may be used. Examples of the phenolic resin-based crosslinking agent include brominated alkylphenol resins and mixed crosslinking systems containing a halogen donor such as tin chloride and chloroprene and an alkylphenol resin.
hr may be used.

[0009] If necessary, a crosslinking accelerator may be added. Examples of the crosslinking accelerator include a general crosslinking accelerator such as aldehyde / ammonia, guanidine, thiazole, sulfenamide, thiuram, dithioate, or thiourea, for example, 0.5 to 2 parts by weight. The degree may be used.

Specifically, hexamethylenetetramine and the like are used as the aldehyde / ammonia crosslinking accelerator; diphenylguanidine and the like are used as the guanidine crosslinking accelerator; dibenzothiazyl disulfide is used as the thiazole crosslinking accelerator. (DM), 2- (4′-morpholinodithio) benzothiazole and the like; as sulfenamide-based crosslinking accelerators, cyclohexylbenzothiazolylsulfenamide (CBS), N-oxodiethylenebenzothiazolyl-2- Sulfenamide, Nt-butyl-2-benzothiazolylsulfenamide, 2-
(Thymoporinyldithio) benzothiazole and the like; tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide (T
MTM), dipentamethylenethiuram tetrasulfide and the like; Examples of the dithioate-based crosslinking accelerator include Zn-dimethyldithiocarbamate, Zn-diethyldithiocarbamate, Zn-di-n-butyldithiocarbamate, and Z
n-ethylphenyldithiocarbamate, Te-diethyldithiocarbamate, Cu-dimethyldithiocarbamate, Fe-dimethyldithiocarbamate, pipecoline pipecolyldithiocarbamate and the like; thiourea-based crosslinking accelerators include ethylenethiourea and diethylthiourea. Each disclosed.

As a crosslinking promoting agent, a general rubber auxiliary agent can be used in combination. For example, zinc white (about 5 parts by weight), stearic acid, oleic acid and their Zn salts (2 -4 weight) or the like.

The thermoplastic elastomer of the present invention may further include other rubbers, softeners, plasticizers, antioxidants, antioxidants, ultraviolet absorbers, coloring agents such as pigments and dyes, carbon black and the like. A filler such as silica may be included as needed.

In the present invention, as a method for dynamically vulcanizing the thermoplastic elastomer, a known production method can be used, but a batch-type production method may be used, or PP may be supplied continuously. A continuous manufacturing method using a twin-screw kneading extruder or the like in which a thermoplastic elastomer is manufactured by sequentially adding and kneading EPDM and a vulcanizing agent while melting and kneading while transferring the mixture may be used. For example, a screw extruder, a kneader, a Banbury mixer, a twin-screw kneading extruder, or the like can be used. Further, kneading may be performed sequentially using two or more types of kneaders. The kneading temperature may be at least the temperature at which PP melts, but is preferably 180 to 220 ° C. The shear rate during kneading is 500-7500 sec.
It is preferably ^-1 . The whole kneading time is 30 seconds to 1
At 0 minutes, the vulcanization time after adding the vulcanization system is from 15 seconds to 5 seconds.
Minutes.

[0014] The thermoplastic elastomer composition produced in this manner is capable of dynamically vulcanizing the rubber while masticating the thermoplastic resin and the rubber composition, that is, dynamically vulcanizing the rubber. Sulfur (Dynamic Cure or Dynamic Vulcan
ization). By utilizing such a manufacturing method, the obtained thermoplastic elastomer composition has a thermoplastic resin phase in which at least a part is a continuous phase, and a vulcanized rubber phase in which at least a part is a discontinuous phase is finely divided. Because it is in a dispersed state, this thermoplastic elastomer composition exhibits the same behavior as the vulcanized rubber, and since at least the continuous phase is a thermoplastic resin phase, at the time of its molding processing, it conforms to the thermoplastic resin. Processing is possible.

In the present invention, polyethylene or an α-olefin-ethylene copolymer is an essential component for ensuring heat fusion with PE. The polyethylene or α-olefin-ethylene copolymer used in the present invention has a Mw of
(Weight average molecular weight) / Mn (number average molecular weight) ≦ 4.0, and preferably 1.5 ≦ Mw / Mn ≦ 3.0. When Mw / Mn is more than 4.0, the distribution of polyethylene or α-olefin-ethylene copolymer is large,
For this reason, since the material starts to melt from a low temperature, a sheet made of the thermoplastic elastomer composition containing the material has insufficient strength at a high temperature (80 ° C.). The density is 0.9
1 (g / cm ³ ) or more and 0.92 to 0.94 (g
/ Cm ³ ). The density is 0.91 (g /
cm ³ ) less than polyethylene or α-olefin
Since the ethylene copolymer has low crystallinity, the strength of the material is low, and the sheet made of the thermoplastic elastomer composition containing the ethylene copolymer also has low tensile strength and tear strength. As the α-olefin,
Examples thereof include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, and 1-octadecene. Among them, 1-hexene, 1-octene and the like are preferable, and the α-olefin content of the copolymer is 0 to 30% by weight, preferably 2 to 10% by weight. As such polyethylene or α-olefin-ethylene copolymer, those polymerized using a metallocene catalyst are preferable. Polyethylene or α-olefin-ethylene copolymer polymerized using a metallocene catalyst has a narrow molecular weight distribution and is homogeneous. When conventional PE is blended to enable thermal fusion with the conventional HDPE sheet, the strength of the sheet at high temperatures is reduced due to the mixture of low molecular weight PE due to the variation in PE molecular weight. However, in the present invention, by using a specific polyethylene or α-olefin-ethylene copolymer, a decrease in the material strength due to heat of the obtained sheet can be suppressed. In addition, due to the homogeneity of the molecular weight, the sheet is extremely uniformly melted at the time of sheet joining, so that the workability at the time of joining, the quality and stability of the joining portion are also enhanced. The amount of the polyethylene or α-olefin-ethylene copolymer in the thermoplastic elastomer composition of the present invention is 5 to 100 parts by weight, preferably 20 to 80 parts by weight, based on 100 parts by weight of the thermoplastic elastomer. . When the blending amount of polyethylene or α-olefin-ethylene copolymer is 1
If the amount is more than 00 parts by weight, the sheet strength at room temperature is reduced. If the amount is less than 5 parts by weight, the sheet cannot be heat-fused to the HDPE sheet.

The thermoplastic elastomer composition of the present invention comprises the above-mentioned thermoplastic elastomer, polyethylene or α-olefin-ethylene copolymer and, if necessary, a filler, etc., using a Banbury mixer, a single-screw or twin-screw extruder, a mixing roll. , Kneader, continuous mixer, etc.
It is obtained by kneading at 80 to 220 ° C for 0.5 to 5 minutes. At this time, if necessary, a filler, an antioxidant, an antistatic agent, a rust inhibitor, a compatibilizer, a colorant, an ultraviolet absorber, a processing aid such as a lubricant, and a dispersant thereof are added. You may. Further, in the present invention, polyethylene or α-olefin-ethylene copolymer may be added at the time of dynamic vulcanization of the thermoplastic elastomer, and the time of addition is not particularly limited.

In particular, in applications such as outdoor sheets requiring weather resistance, carbon black may be added to the thermoplastic elastomer composition of the present invention. By containing carbon black, a thermoplastic elastomer composition having excellent long-term weather resistance can be obtained. Carbon black is E
It may be present in PDM or PP or polyethylene, α-olefin-ethylene copolymer, or both, but based on 100 parts by weight of the total weight of EPDM, PP and ethylene copolymer. It is preferable to add 0.5 to 200 parts by weight.

It is preferable to add a softening agent and / or a plasticizer to the thermoplastic elastomer composition of the present invention since the flexibility of the elastomer can be improved, and it is preferable to form a sheet. When added to EPDM, paraffin-based oils, especially paraffin-based oils having heat resistance, are preferably used from the viewpoint of compatibility.
The addition amount is preferably 50 to 150 parts by weight based on 100 parts by weight of EPDM.

The thermoplastic elastomer composition of the present invention comprises:
Excellent in flexibility, breaking strength under high temperature, belts, rolls, molds, hoses, tubes, electric wires, cables, construction materials, civil engineering materials, agricultural, sheets and films for construction and civil engineering, It can be used for packaging films and the like. In particular, it is suitably used as a waterproof sheet for a waste disposal site, or a waterproof sheet used for a rooftop of a building or a tunnel construction method.

The sheet of the present invention can be obtained by a conventional sheet forming method. For example, the pelletized thermoplastic elastomer composition of the present invention can be formed into a sheet having a desired shape by a T-die extruder, a calendar molding machine, a blow molding machine, an inflation molding machine, or the like. The sheet of the present invention may be used alone, but if necessary, its end is joined to various sheets at the construction site by heat fusion or the like. The sheet of the present invention exhibits sufficient strength in a wide range from low to high temperatures, and can be used for waterproofing rooftops of buildings, waterproofing of industrial waste disposal sites, and other general civil engineering works.

[0021]

EXAMPLES <Preparation of Thermoplastic Elastomer Composition> EPDM, oil, and carbon black were charged into a closed Banbury mixer in accordance with the composition shown in Table 1 below.
The mixture was kneaded at 0 ° C. for 5 minutes to prepare an elastomer component. Thereafter, the elastomer component was pelletized with a rubber pelletizer. Next, PP was charged into the first input port of the twin-screw kneader and kneaded. Thereafter, the elastomer component was input from the second input port, and the elastomer component was sufficiently dispersed in the PP. Further, a vulcanizing system (Zn, stearic acid, brominated phenol) is charged from the third charging port, and a kneading temperature of 20.
After dynamic vulcanization at 0 ° C. and a shear rate of 1150 s ⁻¹ , the strand was extruded from the tip into a strand, and the strand was water-cooled and cooled, and then pelletized with a resin pelletizer to prepare a thermoplastic elastomer.

[0022]

The description in the table is as follows. In addition,
The numerical values in the table represent parts by weight. PP: MJ170 (manufactured by Tokuyama) EPDM: EPT3045 (manufactured by Mitsui Petrochemical) Oil: Machine oil 22 (manufactured by Showa Shell Sekiyu KK) Carbon black: Seast V (manufactured by Tokai Carbon) ZnO: Zinc Hua 3 Stearic acid: Bead stearic acid (manufactured by NOF CORPORATION) Brominated phenol: Tackilol 250-1 (manufactured by Taoka Chemical Co., Ltd.)

<Production of Sheet> A thermoplastic elastomer, various PEs and an α-olefin-ethylene copolymer were mixed in a blender as shown in Table 2 below using a blender, and the resulting mixture was mixed in a single-screw kneading extruder. It was melted at 200 ° C. and extruded from a T-die into a 1.5 mm thick sheet. The obtained sheet was used as a test piece and used in the following evaluation.

<Evaluation of Breaking Strength> Tensile strength and elongation at break were measured at 25, -20 and 80 ° C. in accordance with JIS K6301. Similarly, JIS K6
The tear strength was measured at 20 ° C. in accordance with No. 301. <Adhesive strength with HDPE> Each sheet described in Table 2 was converted to HDP.
A sheet made of E (S6008G, manufactured by Nippon Polyolefin Co., Ltd.) was heat-sealed with a 200 ° C. press at a pressure of 20 kg / cm ² , and a peel test was performed in accordance with JIS K6854. The description in the table is as follows. Interface: Interface fracture Material: Material fracture

<Deterioration test> The following degradation test was performed in accordance with JIS A6008. Thermal degradation test: After degradation by heat treatment at 80 ° C. for 168 hours, in accordance with JIS K6301 as described above,
The tensile strength and elongation at break were measured and compared with those before the test, and the retention was measured. Weather resistance test: Accelerated exposure test with sunshine weatherometer according to JIS A6008 (conditions: 6
3 ° C x 1000 hours, 18 out of 120 minutes spray cycle
Minutes) and then conforms to JIS K6301,
The tensile strength and elongation at break were measured and compared with those before the test, and the retention was measured. Alkali degradation test: After immersion in a saturated solution of calcium hydroxide at 20 ° C. for 168 hours, JI
According to SK6301, the tensile strength and the elongation at break were measured and compared with those before the test, and the retention was measured. Ozone deterioration test: ozone concentration 75 pphm, temperature 40
After deteriorating by ℃, according to JIS K6301,
The tensile strength and elongation at break were measured and compared with those before the test, and the retention was measured.

[0027]

[Table 1]

The description in the table is as follows. In addition,
The numerical values in the table represent parts by weight unless otherwise specified. Thermoplastic elastomer 3: Santoprene 101-64
(Advanced Elastomer Systems Co., Ltd.) α-olefin-ethylene copolymer (using metallocene catalyst): Elite resin 5100 (manufactured by Dow Chemical Company), M
w / Mn = 2.9, density 0.92 (g / cm ³ ) (octene-ethylene copolymer, using metallocene catalyst) HDPE: S6008G (manufactured by Nippon Polyolefin Co., Ltd.),
Mw / Mn = 4.8, density 0.95 (g / cm ³ ) α-olefin-ethylene copolymer: S6008G (manufactured by Nippon Polyolefin Co., Ltd.), Mw / Mn = 4.8, density 0.
91 (g / cm ³ ) (butene-ethylene copolymer)

From Comparative Example 1, unless PE or α-olefin-ethylene copolymer was blended, heat fusion with HDPE could not be performed. Even in the case of the α-olefin-ethylene copolymer having a narrower molecular weight distribution than that of Comparative Example 2, if the blending amount was too large, the strength at ordinary temperature did not increase. Compared with Comparative Examples 3 and 4, it was found that when polyethylene or α-olefin-ethylene copolymer having a wider molecular weight distribution was blended, the strength at high temperatures was not sufficient. Therefore, if a polyethylene or α-olefin-ethylene copolymer having a narrow molecular weight distribution as synthesized by a metallocene catalyst is mixed with a thermoplastic elastomer made of PP / EPDM, heat resistance is high and H
A thermoplastic elastomer composition having high bonding strength with PDE is obtained, and a sheet using this composition can be used as an easily usable and highly reliable sheet in an industrial waste treatment plant or the like.

[0030]

According to the present invention, there is provided a thermoplastic elastomer composition containing an α-olefin-ethylene copolymer which has excellent strength at high temperatures and excellent adhesion to HDPE, and a waterproof sheet comprising the elastomer composition. Can be.

Claims (3)

[Claims] An ethylene-propylene copolymer rubber (EPD)
M) and polypropylene resin (PP) by EPDM / PP
(Weight ratio) 30 / 70-70 / 30
Mw / Mn ≦ 4.0 with respect to 100 parts by weight of the lastmer.
And a density of 0.91 (g / cm ^Three) Polyethylene is more than
Or α-olefin-ethylene copolymer in 5-100
A thermoplastic elastomer composition containing parts by weight. 2. The thermoplastic elastomer composition according to claim 1, wherein said polyethylene or α-olefin-ethylene copolymer is polymerized using a metallocene catalyst. 3. A waterproof sheet comprising the thermoplastic elastomer composition according to claim 1.