JPH10182893A - Sheet for civil engineering work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-weldable sheet for a civil engineering work, improved in oil resistance and tensile strength without detriment to flexibility. SOLUTION: This sheet is made from a composition prepared by mixing 10-40wt.% high-density polyethylene with 40-80wt.% low-density polyethylene having a density of 0.915g/cm<3> or below and 3-30wt.% at least one member selected among an ethylene/butene copolymer, an ethylene/butadiene copolymer and a polymer obtained by hydrogenating part of the double bonds of an ethylene/butadiene copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a civil engineering sheet, and more particularly, to a heat-seamable civil engineering waterproof sheet having improved oil resistance and tensile strength while maintaining flexibility.

[0002]

2. Description of the Related Art Civil engineering sheets are used in waste disposal sites, reservoirs, and various construction sites.
Not only strong tensile strength and sheet bonding properties but also flexibility and oil resistance are important functions of civil engineering waterproof sheets. Vulcanized rubber, polyvinyl chloride, and cross-linked polyolefin have been used as conventional civil engineering sheets. Also, a sheet in which a styrene elastomer is added to a polyolefin is known (JP-A-5-117414).

[0003]

However, many conventional civil engineering sheets have low tensile strength and poor oil resistance at high temperatures. Further, those having improved oil resistance have a drawback of impairing the heat welding property.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, waterproofing for civil engineering which is excellent in high tensile strength and oil resistance at high temperature while maintaining flexibility and which can be thermally welded. We arrived at the invention of the seat. The first invention is
(A) high density polyethylene and (B) density 0.915
g / cm ³ or less of low-density polyethylene (C) selected from hydrogenated ethylene-butene copolymer, ethylene-butadiene copolymer and part of the double bonds of ethylene-butadiene copolymer. The present invention is a sheet for civil engineering using a composition containing one or more of the above,
(A) 10 to 40% by weight of high density polyethylene, (B) 40 to 80% by weight of low density polyethylene having a density of 0.915 g / cm ³ , and (C) ethylene-butene copolymer A composition in which the blending amount of at least one compound selected from hydrogenation treatment of some of the double bonds of the union, ethylene-butadiene copolymer and ethylene-butadiene copolymer is 3 to 30% by weight. It is a sheet for civil engineering used.

The high-density polyethylene (A) used in the present invention has a density of 0.940 g / cm ³ or more obtained by polymerizing ethylene, and is copolymerized with an ethylene homopolymer or an α-olefin containing ethylene as a main component. Any of polymers may be used. Melt index is 0.01 to 10.0 g / 10
min and a density of 0.940 to 0.960 g / cm ³ are preferable, and a melt index of 0.05 to 1.0 g / 10 min and a density of 0.945 to 0.945 are more preferable.
0.955 g / cm ³ is used. (A) The compounding amount of the high-density polyethylene is preferably from 10 to 40% by weight, more preferably from 15 to 35% by weight in the composition. Using the high-density polyethylene (A) specified in this way,
By setting the blending amount, a good sheet having good productivity and good stress cracking resistance and excellent balance between tensile strength and flexibility can be obtained.

The low-density polyethylene (B) used in the present invention is a polyethylene obtained by copolymerizing ethylene and an α-olefin and having a density of 0.915 g / cm ³ or less. The low-density polyethylene (B) is preferably a linear low-density polyethylene having a rubber component of less than 15% by weight and having no long-chain branch, and a melt index of 0.3 to 10.0 g / 10 mi.
n, more preferably 0.5 to 2.
0 g / 10 min, density 0.89 to 0.91 g / cm ³
Use The amount of the low-density polyethylene (B) is preferably 40 to 80% by weight, more preferably 50 to 75% by weight in the composition. By using the low-density polyethylene (B) specified as described above and adjusting the blending amount, a good sheet excellent in productivity and flexibility can be obtained.

The ethylene-butene copolymer used in (C) of the present invention is preferably an ethylene-butene copolymer having a butene content of 10% by weight or more.
For the butadiene copolymer, the butadiene content is 1
The ethylene-butadiene copolymer is desirably 0% by weight or more, and the hydrogenated ethylene-butadiene copolymer desirably has at least 80% of the double bond portion saturated. These copolymers are 90 ° C
Those having the above melting point are desirable. The compounding amount of the above (C) is preferably 3 to 30% by weight in the composition, more preferably 5 to 25% by weight. By using the (C) specified in this way and setting the blending amount, a sheet having both flexibility and high tensile strength can be obtained.

[0008] The sheet of the present invention is characterized by being obtained from a composition containing the above components in a predetermined amount. However, as long as the basic performance of the waterproof sheet of the present invention is not impaired, ethylene-vinyl acetate copolymer and styrene-based sheet are used. Resins such as elastomers,
Or carbon black, pigments other than carbon black,
Components such as inorganic fillers such as talc, calcium carbonate and mica, antioxidants, ultraviolet absorbers and lubricants can be added.

The civil waterproofing sheet of the present invention has an Olesen bending strength of less than 300 MPa and a tensile strength of 2800 N / c.
m2 or more, oil resistance is 70 ° C of JIS-2 oil x
It is desirable that the tensile strength residual ratio after immersion for 168 hours is 50% or more, and the Olesen bending strength is 280 MPa.
It is desirable to be less than.

[0010]

EXAMPLES For each of the compositions of Examples 1 to 10 and Comparative Examples 1 to 8, the blends shown in Table 1 were pellet-blended and then melt-kneaded at 180 to 250 ° C. with an extruder. To form a sheet having a thickness of 2.0 mm.

The following materials were used for this study. Component A High-density polyethylene: (manufactured by Chisso; MI 0.12 g / 10 min,
Density 0.95 g / cm ³⁾ Component B low density polyethylene :( Tosoh; MI0.8g / 10min, density 0.90 g / cm ³⁾ Component C ethylene - butene copolymer (manufactured by JSR; 2021P;
MI 1.3 g / 10 min, phthalene content 20% by weight) Hydrogenated ethylene-butadiene copolymer (610 from JSR;
0P; MFR 0.6 g / 10 min, density 0.88 g / cm ³ , melting point 94 ° C., component D ethylene-propylene-diene copolymer: (manufactured by JSR;
EP133P; MFR 1.5 g / 10 min, density 0.86 g / cm ³ ) Styrene elastomer (manufactured by JSR; 1320P; MF)
R3.5g / 10min, density 0.89 g / cm ^3, a styrene content of 10 wt%)

Each sheet was evaluated for flexibility, tensile strength, oil resistance and heat welding property, and evaluated according to the criteria shown in Table 2.

[0013]

Each evaluation item was performed by the following test methods.・ Melt index (MI): JIS K 6760 (190 ° C.-2.16 kgf) ・ Melt flow rate (MFR): ASTM D 1238 (230 ° C.-2.16 kgf) ・ Olsen bending strength: JIS K 7106 ・ Tensile strength: JIS A 6008 (Tensile speed: 200 mm / min) ・ Oil resistance: JIS K 6301 Using JIS No. 2 oil, evaluated by residual tensile strength after immersion at 70 ° C. for 168 hours ・ Melting point: Measured by JIS K 7121, DSC ・ Heat welding property: Evaluated by the presence or absence of peeling due to shear peeling after heat welding with a welding machine

Examples 1 to 10 All obtained sheets having high tensile strength and good oil resistance while maintaining flexibility.

Comparative Example 1 An uncrosslinked ethylene / propylene / diene copolymer was used for the part (C), but the tensile strength and oil resistance were poor.

Comparative Examples 2 to 3 As in Comparative Example 2, when the high-density polyethylene was used in the same composition and the portion (C) was not used, the tensile strength was poor. Further, when the amount of high-density polyethylene is increased to increase the tensile strength as in Comparative Example 3, the flexibility is lost.

Comparative Examples 4 to 7 When high density polyethylene is not used as in Comparative Example 4,
Oil resistance decreases. When low-density polyethylene is not used as in Comparative Examples 5 to 7, oil resistance is not improved.

Comparative Example 8 As in Comparative Example 8, the styrene elastomer has poor oil resistance.

Since no cross-linked resin was used for the heat-welding property, the results obtained in all of the examples and comparative examples were that there was no peeling.

[0021]

The sheet for civil engineering according to the present invention has good properties in both tensile strength and oil resistance while maintaining flexibility, and can be thermally welded, and can be used for various purposes such as waste disposal sites and reservoirs. It can be suitably used in various construction sites.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

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Claims (2)

[Claims] 1. A high density polyethylene (A) and (B)
(C) Ethylene-butene copolymer, ethylene-butadiene copolymer and a part of double bonds of ethylene-butadiene copolymer hydrogenated to low-density polyethylene having a density of 0.915 g / cm ³ or less 1 selected from
Civil engineering sheet using a composition containing more than one species. 2. A high-density polyethylene (A) compounding amount of 1
0 to 40% by weight, (B) 40 to 80% by weight of low density polyethylene having a density of 0.915 g / cm ³ , and (C) ethylene-butene copolymer, ethylene-butadiene copolymer and ethylene. -A sheet for civil engineering using a composition in which at least one compound selected from hydrogenation treatment of a part of the double bond of the butadiene copolymer is 3 to 30% by weight.