JP2001316536A - Waterproofing sheet material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for waterproofing sheet, capable of giving such a waterproofing sheet at a low cost that is excellent and well balanced in water resistance, heat resistance, and oil resistance, further has excellent flexibility, shape stability, and applicability, and therefore is substitutable for a PVC(polyvinyl chloride) sheet. SOLUTION: This resin composition for the waterproofing sheet comprises (A) an ethylene-vinyl acetate copolymer resin which contains a component derived from the vinyl acetate in an amount of >=10 wt.% and (B) a thermoplastic polyurethane, wherein the components (A) and (B) are contained in amounts of 49-95 wt.% and 5-51 wt.%, respectively, provided that, the total amount of the components (A) and (B) is 100 wt.%. The waterproofing sheet is obtained by molding the resin composition, and gives a water-sealing sheet for a waste disposal ground and a waterproofing sheet for a water bed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a resin composition for a waterproof sheet and a waterproof sheet comprising the resin composition. More specifically, a specific ethylene-vinyl acetate copolymer and a thermoplastic polyurethane, water resistance, heat resistance comprising a resin composition and the resin composition blended in a specific ratio,
The present invention relates to an inexpensive waterproof sheet having excellent oil resistance and the like.

[0002]

BACKGROUND OF THE INVENTION A waterproof sheet used in civil engineering, architecture, indoor and outdoor interiors, or a waterproof sheet used as a water bed sheet enclosing water and having a fixed shape is used in an environment where water is present. To be used, it is necessary to have a certain level of water resistance, and since the waterproof sheet is used under various environmental conditions such as indoor, outdoor, underground, in order to widely support various applications Are required to have properties such as heat resistance and oil resistance, depending on the form of use, and are required to be excellent in such properties in a well-balanced manner.

[0003] For example, when used in the field of civil engineering and construction, for example, in waste disposal sites such as waste liquid treatment and garbage disposal sites, hazardous substances flowing out of various wastes,
It is necessary to block permeation of contaminated liquids and oils from the viewpoint of safety, etc., and to have resistance to acids, alkalis, oils, etc. in wastes, and to handle the high temperatures associated with garbage incineration, etc. Must withstand use.

Heretofore, inexpensive polyvinyl chloride (PVC) having water resistance, acid resistance, workability, and the like, has been often used for such a waterproof sheet. However,
In response to the recent dioxin problem and the like, the use of PVC has been restricted, and the development of alternatives for waterproof sheet materials has been required. For this reason, in recent years, development of waterproof sheets using ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate copolymer, urethane, etc. has been attempted, but in terms of strength, heat resistance, oil resistance, and the like. There was a problem that it was not enough. Attempts have also been made to develop a sheet in which these resin sheets are appropriately laminated, but there is a problem in practical use such as an increase in cost.

For example, ethylene vinyl acetate copolymers are used for waste incineration facilities, or in hot and humid areas such as hot springs, and in hot and dry areas such as desert areas where the temperature difference between day and night is large. , Heat resistance and weather resistance. In addition, a waterproof sheet using polyurethane is used as a water barrier sheet in a waste treatment plant, but a urethane sheet is expensive and has a hydrolytic property, so it is used for a long period under high temperature and high humidity conditions. However, there is a limit in a sheet composed of urethane alone.
On the other hand, a waterproof sheet using EVA has a great practical advantage of low cost, but has poor strength, resilience after compression and tension, and poor elasticity, and may be deformed by continuous use. There was such a problem.

Japanese Patent Application Laid-Open No. 7-238220 discloses a resin composition comprising a thermoplastic polyurethane and an ethylene-vinyl acetate copolymer, wherein the content of the thermoplastic polyurethane is more than 50%. Although the polyurethane resin composition is improved in heat resistance for use in insulating materials such as electric wires, such a resin composition has water resistance, oil resistance and the like. There is no description that it is excellent and useful as a waterproof sheet,
In addition, there is also a problem that the price is still expensive because polyurethane is a main component.

For this reason, PVC which has excellent properties such as water resistance, heat resistance, oil resistance, etc., and is practical at low cost
There has been a demand for a new waterproof sheet material. Therefore, the present inventors have intensively studied to solve the above problems, and a waterproof sheet made of a composition in which polyurethane is mixed with a certain ratio of polyurethane with high water resistance and low cost based on EVA, The present inventors have found that the present invention is excellent in heat resistance, oil resistance, flexibility, shape stability, and workability while maintaining the water resistance performance derived from EVA at a low cost, and has completed the present invention.

[0008]

SUMMARY OF THE INVENTION The present invention provides a low cost, water resistant,
An object of the present invention is to provide a waterproof sheet in place of PVC and a composition capable of obtaining such a waterproof sheet, which is excellent in heat resistance and oil resistance in a well-balanced manner, and also excellent in flexibility, shape stability and workability. I have.

[0009]

SUMMARY OF THE INVENTION A resin composition for a waterproof sheet according to the present invention comprises an ethylene-vinyl acetate copolymer resin (A) containing at least 10% by weight of a component derived from vinyl acetate, and a thermoplastic polyurethane (B). Wherein the ethylene-vinyl acetate copolymer (A) is 49 to 95% by weight and the thermoplastic polyurethane (B) is 5 to 51% by weight (provided that (A) + (B) =
(100% by weight). The ethylene-vinyl acetate copolymer (A) is 51 to
90% by weight, 10 to 4% of the thermoplastic polyurethane (B)
It is preferably contained in a proportion of 9% by weight (however, (A) + (B) = 100% by weight). The content of the component derived from vinyl acetate contained in the ethylene-vinyl acetate copolymer resin (A) is preferably from 10% by weight to 40% by weight.

A waterproof sheet according to the present invention is characterized by comprising the above resin composition for a waterproof sheet. The water stoppage sheet for a waste disposal plant according to the present invention is characterized by being made of the waterproof sheet. The waterproof sheet for a water bed according to the present invention is characterized by comprising the waterproof sheet.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The resin composition for a waterproof sheet according to the present invention comprises an ethylene-vinyl acetate copolymer resin (A) containing at least 10% by weight of a component derived from vinyl acetate, and a thermoplastic polyurethane (B). Consists of Hereinafter, the resin composition for a waterproof sheet will be described. <Ethylene-vinyl acetate copolymer resin (A)> The ethylene-vinyl acetate copolymer resin (A) of the present invention (hereinafter sometimes referred to as “EVA”) (A) has a content of a component derived from vinyl acetate ( Hereinafter, it may be referred to as “vinyl acetate content”) is 10% by weight or more, preferably 10 to 40% by weight, and more preferably 15 to 40% by weight. When the vinyl acetate content in the ethylene-vinyl acetate copolymer is less than 10% by weight, the compatibility with the thermoplastic polyurethane is reduced, and the surface of the formed waterproof sheet may be peeled off. When the vinyl acetate content exceeds 40% by weight, the softening point of the obtained waterproof sheet is lowered, and a problem may occur in heat resistance. The vinyl acetate content is JI
It was measured according to S K6730-1981.

The copolymer form of the ethylene-vinyl acetate copolymer is not particularly limited, and may be any of a random copolymer and a block copolymer. The melt flow rate of such an ethylene vinyl acetate copolymer is usually
1.5-20g / 10min, preferably 2.0-10g / 10mi
n, particularly preferably 2.0 to 5.0 g / 10 min.

The ethylene-vinyl acetate copolymer has a density of usually 0.9 to 1.0 g / cm ³ , preferably 0.93 g / cm ³ .
Desirably, it is 0.95 g / cm ³ . The method for producing such an ethylene-vinyl acetate copolymer is not particularly limited, and it can be obtained by a method of copolymerizing with a usual radical initiator, and a commercially available product can also be used. <Thermoplastic polyurethane (B)> The thermoplastic polyurethane according to the present invention (hereinafter sometimes referred to as “TPU”).
(B) can be obtained by reacting a polyisocyanate, a polyol and a chain extender. (Polyisocyanate) Examples of the polyisocyanate used as a raw material of the thermoplastic polyurethane according to the present invention include phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and the like.
Aromatic diisocyanates such as tetramethylxylylene diisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate and isomers thereof;
1,6-hexamethylene diisocyanate, 1,12-
Aliphatic diisocyanates such as dodecane diisocyanate and trimethyl-hexamethylene diisocyanate; alicyclic diisocyanates such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and norbornane-diisocyanate methyl.

Further, compounds having terminal isocyanate groups obtained by reacting these compounds with compounds having active hydrogen groups can also be used. Furthermore, a modified polyisocyanate such as a compound in which the polyisocyanate compound is carbodiimidated can also be used. Also,
A part of the isocyanate group of the polyisocyanate compound is blocked by a compound having one active hydrogen in a molecule such as methanol, n-butanol, benzyl alcohol, ethyl acetoacetate, ε-caprolactam, methyl ethyl ketone oxime, phenol, and cresol. Stabilized polyisocyanates can also be used.

These can be used alone or in combination of two or more. (Polyol) As the polyol which is a raw material of the thermoplastic polyurethane according to the present invention, polyether polyols, polyester polyols, polyester amides, polyethers having an active hydrogen group such as a hydroxyl group or an amine group at a terminal are usually used. Examples include ester polyols and polycarbonates.

Examples of the polyether polyols include those obtained by polymerizing or copolymerizing (block or random) alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide, and heterocyclic ethers such as tetrahydrofuran, or polyether polyols. Examples thereof include those obtained by graft-polymerizing a vinyl monomer to an ether polyol, such as polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random copolymerized) glycol, polytetramethylene ether glycol, and polyhexamethylene ether. Glycol, polyoctaethylene ether glycol and mixtures of two or more thereof.

Examples of the polyester polyols and polyester amides include those usually obtained by polycondensation of polyhydric alcohols and polycarboxylic acids, or those obtained by using diamines or amino alcohols in some cases. Can be Examples of such polyhydric alcohols include ethylene glycol, diethylene glycol, butylene glycol, hexamethylene glycol, 2-methylpropanediol, neopentyl glycol, 3-methylpentanediol, 2-methyloctanediol, 1,9- Nonanediol, cyclohexanedimethanol, glycerin, trimethylolpropane and the like can be mentioned. Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, dimer acid, hydrogenated dimer acid, phthalic acid, alkyl phthalates, trimellitic acid, maleic acid, fumaric acid, and itaconic acid. Can be Further, those obtained by ring-opening polymerization of a cyclic ester such as butyrolactone, valerolactone, and caprolactone are also included.

The polyetherester polyols include those obtained by using the above-mentioned polyether polyols for a part or all of the polyhydric alcohols used in the condensation reaction for obtaining the polyester polyols. Examples include those obtained by polycondensation using the same polycarboxylic acids and polyhydric alcohols as the polyester polyols.

As the polycarbonates, those obtained by transesterification of a diol such as 1,6-hexanediol and 1,4-cyclohexanedimethanol with a cyclic carbonate such as dialkyl carbonate, diaryl carbonate or ethylene carbonate are used. Is mentioned. Among these polyols, since the sheet obtained in the present invention is preferably used even in an aqueous environment, ester polyols are preferable from the viewpoint of mold prevention and the like.Specifically, polyester polyols and polyether esters are used. It can be preferably used.

The number average molecular weight of such a polyol is:
Usually 400 to 10000, preferably 1000 to 300
Desirably, it is 0. If the number average molecular weight is smaller than 400, the moldability may be deteriorated, and the molecular weight may be less than 100.
If it is larger than 00, the fluidity when mixing the ethylene vinyl acetate copolymer and the thermoplastic polyurethane by melt mixing or the like may be deteriorated, and uniform mixing may be impaired. (Chain extender) Examples of the chain extender for the thermoplastic polyurethane (B) according to the present invention include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,9-nonane. Diol, bis-β-hydroxyethoxybenzene, 3
-Methyl-1,5-pentanediol, neopentyl glycol, N-phenyldiisopropanolamine, monoethanolamine and the like.

The ratio of the number of moles of isocyanate groups contained in the polyisocyanate to the total number of moles of all active hydrogen groups contained in the polyol and the chain extender (R
Value) is 0.7 to 1.3, preferably 0.9 to 1.1. Further, in the chain extender and the polyol, a ratio (R ′ value) of the number of moles of active hydrogen groups of the chain extender to the number of moles of active hydrogen groups of the polyol
Is desirably blended so as to be 0.5 to 10.0, preferably 1.0 to 4.0. (Catalyst) In the reaction between the polyisocyanate and the polyol or the like according to the present invention, a catalyst can be added as necessary. Examples of such a catalyst include triethylamine, triethylenediamine, N-methylimidazole, N-ethylmorpholine, 1,8-diazabicyclo [5,4,0] undecene-7 (DBU).
Amines; organic metals such as potassium acetate, stannas octoate, and dibutyltin dilaurate; and phosphorus compounds such as tributylphosphine, phosphorene, and phosphorene oxide. (Method for Producing Thermoplastic Polyurethane) The method for producing the thermoplastic polyurethane according to the present invention is not particularly limited, and a known method can be employed. For example, it can be produced by a known one-shot method, a prepolymer method or a batch reaction method, a continuous reaction method, a production method using a kneader, a production method using an extruder, or the like. Among them, for example, according to a production method using a kneader, a polyol and a chain extender are charged into a kneader, heated to about 80 ° C., polyisocyanate is added, and the mixture is allowed to react for about 10 to 60 minutes, and then cooled, Powdery or block-like thermoplastic polyurethane can be produced. The powdery or block-like thermoplastic polyurethane resin obtained in this manner can be used by being pulverized as it is, or can be made into a pellet by an extruder or the like, if necessary.

Further, in the production of such a thermoplastic polyurethane resin, a kneader connected with a multi-component lightweight mixer or the like, a single-screw or multi-screw extruder, or the like can be used. <Resin composition for waterproof sheet> The resin composition for waterproof sheet according to the present invention comprises the ethylene-vinyl acetate copolymer (A) and the thermoplastic polyurethane (B).

In such a resin composition for a waterproof sheet, the ethylene-vinyl acetate copolymer (A) is contained in a proportion of 49 to 95% by weight, and the thermoplastic polyurethane (B) is contained in a proportion of 5 to 51% by weight. The ethylene-vinyl acetate copolymer
(A) 51-90% by weight of the thermoplastic polyurethane (B)
Is desirably contained at a ratio of 10 to 49% by weight. (However, (A) + (B) = 100% by weight) When the blending amount of the ethylene vinyl acetate copolymer and the thermoplastic polyurethane is in such a range, the waterproofing obtained from the obtained waterproofing sheet composition is obtained. The sheet has improved water resistance, heat resistance, and oil resistance (tensile strength) as compared with a waterproof sheet containing the ethylene vinyl acetate copolymer alone.
Among them, a waterproof sheet having particularly excellent heat resistance and oil resistance can be obtained.

In addition, the resin composition for a waterproof sheet according to the present invention may further contain other additives as necessary, as long as the compatibility between the ethylene-vinyl acetate copolymer (A) and the thermoplastic polyurethane (B) is not impaired. Agents can be added. Examples of such additives include antioxidants, ultraviolet absorbers, heat resistance improvers, plasticizers, lubricants, antistatic agents, conductivity-imparting agents, coloring agents, inorganic fillers, organic fillers, and fibrous reinforcing materials. , A hydrolysis inhibitor, a reaction retarder and the like.

Further, the resin composition for a waterproof sheet according to the present invention is blended with another resin within a range that does not impair the excellent properties of the waterproof sheet according to the present invention such as water resistance, heat resistance and oil resistance. be able to. Examples of such resins include:
For example, polyester-based resins, polyolefin-based resins, polyacryl-based resins, polyamide-based resins and the like can be mentioned.

The method of mixing the ethylene-vinyl acetate copolymer (A) and the thermoplastic polyurethane (B) is not particularly limited, but a method of simply mixing (A) and (B), or a method of melting and mixing these. However, it is preferable to use melt mixing from the viewpoint of ensuring uniform mixing. Examples of such a melt mixing method include known general-purpose thermoplastic resin kneading apparatuses such as a single-screw extruder, a multi-screw extruder, a mixing roll, a Banbury mixer, and a kneader. Thus, a resin composition in the form of a pellet, a powder, or the like can be obtained. <Waterproof sheet> A waterproof sheet using the resin composition for a waterproof sheet according to the present invention is obtained by molding pellets or the like of the resin composition for a waterproof sheet obtained as described above by a known molding method. It is possible to use methods such as extrusion molding, injection molding, blow molding, calendering, roll processing, press processing, stretch molding, and rotational molding.

The thickness of the waterproof sheet varies depending on the use of the waterproof sheet and is not particularly limited.
It is about μm. Since such a waterproof sheet is based on an ethylene-vinyl acetate copolymer that does not generate dioxins and the like and contains a certain amount of thermoplastic polyurethane, it is superior to a sheet of ethylene-vinyl acetate copolymer alone. It has waterproof properties. Furthermore, it is excellent in heat resistance, oil resistance, flexibility, shape stability, workability, and the like. In addition, there is a great practical advantage that the cost is lower than that of a waterproof sheet made of another material developed as a substitute for PVC.

Such a sheet is particularly useful as a waterproof sheet in construction and civil engineering, for example, in a waste disposal site where high temperature and waste oil may flow out. It is also useful as a waterproof sheet material for interiors such as water beds and water cushions that require strength and shape stability. In addition, the waterproof sheet according to the present invention is, as described above, flexible and excellent in shape stability, not only for use as a waterproof sheet,
For example, it is useful as a sheet material for air beds and the like.

[0029]

According to the resin composition for a waterproof sheet according to the present invention, it is inexpensive and excellent in water resistance, heat resistance and oil resistance in a well-balanced manner, and also excellent in flexibility, shape stability and workability. In addition, a waterproof sheet replacing PVC can be obtained.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples.

[0031]

Example 1 70 parts by weight of an ethylene vinyl acetate copolymer having a vinyl acetate content of 25% (Evatate K2010 (trade name), manufactured by Sumitomo Chemical Co., Ltd.) and a polyurethane resin (E180PNAT)
(Trade name, manufactured by Nippon Milactran Co., Ltd.) and melted and mixed at a processing temperature of 190 ° C. using a single screw extruder, and then cooled to room temperature to obtain a composition comprising EVA and a polyurethane resin. A pellet was obtained. These pellets were injection molded at a processing temperature of 195 ° C. using an injection molding machine to form a sheet having a thickness of about 2 mm. Tensile strength of this sheet at normal temperature, water-resistant tensile strength at 80 ° C, heat-resistant tensile strength at 80 ° C, oil-resistant tensile strength at 80 ° C,
The oil resistance volume change rate was measured by the following method. Table 1 shows the measurement results. (1) Tensile strength at room temperature A test piece (110 mm × 55 mm × 2 mm (thickness)) of the sheet after formation was prepared, and a tensile test was performed by a method specified in JISK7311. (2) Water resistant tensile strength at 80 ° C. Sheet test piece (110 mm × 55 mm × 2 mm (thickness))
Was exposed to water at 80 ° C. for 72 hours, and then subjected to a tensile test according to the method specified in JIS K7311. (3) Heat-resistant tensile strength at 80 ° C Test piece of sheet (110 mm x 55 mm x 2 mm (thickness))
Was exposed to a drying electric furnace at 80 ° C. for 72 hours.
A tensile test was performed according to the method specified in K7311. (4) Oil resistant tensile strength at 80 ° C. Sheet test specimen (110 mm × 55 mm × 2 mm (thickness))
Was exposed to ASTM No. 1 oil heated to 80 ° C. for 24 hours, and then subjected to a tensile test according to the method specified in JIS K7311. (5) Oil-resistant volume change rate The oil-resistant volume change rate is determined by the method specified in JIS K 6258.
Determined after 24 and 72 hours exposure.

[0032]

Comparative Example 1 In Example 1, the vinyl acetate content was 25%.
% Ethylene vinyl acetate copolymer (Evatate K2010
(Trade name, manufactured by Sumitomo Chemical Co., Ltd.) Instead of 70 parts by weight, an ethylene vinyl acetate copolymer having a vinyl acetate content of 5% (Evatate D2045 (trade name), manufactured by Sumitomo Chemical Co., Ltd.)
A sheet having a thickness of about 2 mm was obtained in the same manner as in Example 1 except that 70 parts by weight was used. About this sheet, similarly to Example 1, the tensile strength of this sheet at normal temperature,
The water-resistant tensile strength at 80 ° C., the heat-resistant tensile strength at 80 ° C., the oil-resistant tensile strength at 80 ° C., and the oil volume change rate were measured by the following methods. Table 1 shows the measurement results.

[0033]

Comparative Example 2 In Example 1, the vinyl acetate content was 25%.
% Ethylene vinyl acetate copolymer (Evatate K2010
(Trade name) manufactured by Sumitomo Chemical Co., Ltd.) and 30 parts by weight of a polyurethane resin (E180PNAT (trade name) manufactured by Nippon Miractran Co.) instead of using 70 parts by weight, the same vinyl acetate content as described above was 25%. A sheet having a thickness of about 2 mm was obtained in the same manner as in Example 1 except that the ethylene vinyl acetate copolymer (Evatate K2010 (trade name), manufactured by Sumitomo Chemical Co., Ltd.) was used alone. About this sheet, similarly to Example 1, the tensile strength of this sheet at normal temperature, the water-resistant tensile strength at 80 ° C, the heat-resistant tensile strength at 80 ° C,
Oil-resistant tensile strength and oil-resistant volume change at 80 ° C. were measured by the following methods. Table 1 shows the measurement results. In addition,
In Table 1, “x” of 80 ° C. heat resistance means that the sheet test piece was shrunk by heat and could not be measured, and “×” of 80 ° C. oil resistance and oil volume change rate was a sheet test piece. But 8
It means that it was difficult to maintain the shape of the sheet because it was dissolved by the oil at 0 ° C., and the measurement could not be performed.

[0034]

[Table 1]

From these results, it was found that the vinyl acetate content was 25%.
A 2 mm thick sheet using 70 parts by weight of EVA (weight%) and 30 parts by weight of polyurethane (Example 1) is a sheet using the same amount of EVA having a vinyl acetate content of 5% by weight (Comparative Example 1). As compared with the above, all of the water resistance, the heat resistance, the oil resistance, and the rate of change were excellent, and in particular, the tensile strength related to the oil resistance showed a remarkably high value. When EVA having a vinyl acetate content of 25% by weight is used alone (Comparative Example 2), the sheet shrinks at the time of heat resistance evaluation at 80 ° C.
In the evaluation of oil resistance at 80 ° C. and the rate of change in oil volume, it was difficult to maintain the shape of the sheet, and the characteristics could not be evaluated.

[0036]

Example 2 50 parts by weight of an ethylene vinyl acetate copolymer having a vinyl acetate content of 25% (Evatate K2010 (trade name), manufactured by Sumitomo Chemical Co., Ltd.) and a polyester polyol-based polyurethane resin (E180PNAT (trade name)) And 50 parts by weight of Nippon Milactran Co., Ltd.), and using a single screw extruder,
The mixture was melted and mixed at a processing temperature of 190 ° C., and then cooled to room temperature to obtain a pellet of a composition comprising EVA and a polyurethane resin. The pellet was extruded at a processing temperature of 200 ° C. using a single screw extruder to form a sheet having a thickness of about 300 μm. Tensile strength of this sheet at room temperature, water-resistant tensile strength at 80 ° C, heat-resistant tensile strength at 80 ° C,
The oil resistance tensile strength at 0 ° C. was measured by the same method as in Example 1, and the flexibility, shape stability and workability of the sheet were measured by the following methods. Table 2 shows the measurement results. (6) Flexibility A 100 mm × 20 mm × 0.3 mm (thickness) sheet sample cut into a strip shape is cantilevered from the end of the test table by cantilever support.
After projecting the length of mm and leaving the sheet to stand for 30 seconds, the difference in height between the ends of the sheet before and after the sheet was bent was measured to evaluate the flexibility. (7) Shape stability Permanent elongation was measured based on JIS K6301 to evaluate shape stability. (8) Workability The high-frequency welder is used to fuse sheets of the same material,
After standing at room temperature for 24 hours, the tear strength was measured according to JIS K 7311.
And evaluated the on-site workability (easiness of adhesion).

[0037]

Example 3 70 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 25% (Evatate K2010 (trade name), manufactured by Sumitomo Chemical Co., Ltd.) and a polyurethane resin (E180PNAT)
(Trade name), polyester polyol-based polyurethane,
30 parts by weight of Nippon Milactran Co., Ltd.) and melt-mixed at a processing temperature of 190 ° C. using a single screw extruder, and then cooled to room temperature to obtain pellets of a composition comprising EVA and a polyurethane resin. The pellet was extruded at a processing temperature of 200 ° C. using a single screw extruder to form a sheet having a thickness of about 300 μm. Tensile strength of this sheet at room temperature,
Water resistant tensile strength at 80 ° C., heat resistant tensile strength at 80 ° C., oil resistant tensile strength at 40 ° C., sheet flexibility, shape stability and workability were measured by the same methods as in Examples 1 and 2. . Table 2 shows the measurement results.

[0038]

Example 4 70 parts by weight of an ethylene vinyl acetate copolymer having a vinyl acetate content of 25% (Evatate K2010 (trade name), manufactured by Sumitomo Chemical Co., Ltd.) and a polyurethane resin (E380PNAT)
(Trade name), polyether polyol-based polyurethane,
30 parts by weight of Nippon Milactran Co., Ltd.) and melt-mixed at a processing temperature of 190 ° C. using a single screw extruder, and then cooled to room temperature to obtain pellets of a composition comprising EVA and a polyurethane resin. The pellet was extruded at a processing temperature of 200 ° C. using a single screw extruder to form a sheet having a thickness of about 300 μm.

The tensile strength of this sheet at room temperature was 80
Waterproof tensile strength at 80 ° C, heat resistant tensile strength at 80 ° C, oil resistant tensile strength at 40 ° C, sheet flexibility, shape stability and workability were measured in Examples 1 and 2.
It was measured by the same method as described above. Table 2 shows the measurement results.

[0040]

Comparative Example 3 In Example 2, the content of vinyl acetate was 25.
% Ethylene vinyl acetate copolymer (Evatate K2010
(Trade name) manufactured by Sumitomo Chemical Co., Ltd.) and 30 parts by weight of a polyurethane resin (E180PNAT (trade name) manufactured by Nippon Milactran Co., Ltd.), instead of ethylene having the same vinyl acetate content of 25%. A sheet having a thickness of about 300 μm was obtained in the same manner as in Example 2 except that the vinyl acetate copolymer (Evatate K2010 (trade name), manufactured by Sumitomo Chemical Co., Ltd.) was used alone. Tensile strength of this sheet at room temperature, 8
Examples 1 and 2 show the water-resistant tensile strength at 0 ° C., the heat-resistant tensile strength at 80 ° C., the oil-resistant tensile strength at 40 ° C., the sheet flexibility, the shape stability and the workability.
It was measured by the same method as described above. Table 2 shows the measurement results.

[0041]

Reference Example 1 In Example 2, the vinyl acetate content was 25%.
% Ethylene vinyl acetate copolymer (Evatate K2010
Instead of using 70 parts by weight (trade name, manufactured by Sumitomo Chemical Co., Ltd.) and 30 parts by weight of a polyester polyol-based polyurethane resin (trade name: E180PNAT (trade name), manufactured by Nippon Milactran Co., Ltd.), a polyurethane resin (E180PNAT (trade name) Example 2), except that N.I.
In the same manner as in the above, a sheet having a thickness of about 300 μm was obtained. The tensile strength at room temperature, the water-resistant tensile strength at 80 ° C., the heat-resistant tensile strength at 80 ° C., the oil-resistant tensile strength at 40 ° C., the flexibility, shape stability and workability of the sheet were determined in Examples 1 and 2. It measured by the same method as 2. Table 2 shows the measurement results.

In Table 2, the cost performance indicates the cost performance as compared with other waterproof sheets developed as a substitute for PVC, and 低 and ○ indicate a low price and a x indicates a high price.

[0043]

[Table 2]

From these results, it was found that the vinyl acetate content was 25%.
% EVA and 50 parts by weight of polyurethane resin (Example 2), or 70 parts by weight of EVA having a vinyl acetate content of 25% and polyurethane resin 3
The sheet using 0 parts by weight (Examples 3 and 4) is superior in water resistance, heat resistance, and oil resistance as compared with the sheet using only EVA having a vinyl acetate content of 25% (Comparative Example 3). In addition, it has various properties required for a waterproof sheet, such as excellent flexibility, shape stability and workability, in a well-balanced manner. Also, as compared with the sheet using the polyurethane resin alone (Reference Example 1), the sheet is comparable to the polyurethane resin sheet or has excellent characteristics in a well-balanced manner.

Further, the waterproof sheets shown in Examples 2 to 4 according to the present invention have not only the above-mentioned excellent characteristics but also a practically important merit of low cost. The waterproof sheet described in Example 3 or Example 4 is low cost.

Continued on the front page (72) Inventor Tsutomu Suzuki 150, Motomiyamichi, Kawada, Shinshiro-shi, Aichi Pref. Nippon Valqua Industry Co., Ltd. Shinshiro Plant (72) Inventor Hiroshi Terayama 3-Moridai, Atsugi-shi, Kanagawa 17-2 F term (reference) 4D004 AA46 BB05 4F071 AA15X AA28X AA53 AA75X AA76X AF02 AF45 AH03 AH04 AH19 BA01 BB05 BB06 BC01 4J002 BB06W CK02X CK03X CK04X CP03W

Claims (6)

[Claims] 1. The content of a component derived from vinyl acetate is 1
0% by weight or more of ethylene vinyl acetate copolymer resin (A)
And the thermoplastic polyurethane (B), wherein the ethylene-vinyl acetate copolymer (A) is 49 to 95% by weight, and the thermoplastic polyurethane (B) is 5 to 51% by weight (provided that (A) + (B) = 100% by weight). 2. The ethylene-vinyl acetate copolymer (A) comprises 51 to 90% by weight, and the thermoplastic polyurethane (B) comprises 1% by weight.
2. The resin composition for a waterproof sheet according to claim 1, wherein the resin composition is contained in a proportion of 0 to 49% by weight (however, (A) + (B) = 100% by weight). 3. The ethylene-vinyl acetate copolymer resin
The content of the component derived from vinyl acetate contained in (A) is 1
2. The composition according to claim 1, wherein the content is 0% to 40% by weight.
3. The resin composition for a waterproof sheet according to item 1. 4. A waterproof sheet comprising the resin composition for a waterproof sheet according to claim 1. 5. A water-stop sheet for a waste disposal plant, comprising the waterproof sheet according to claim 4. 6. A waterproof sheet for a water bed comprising the waterproof sheet according to claim 4.