JP2503392Y2 - Waterproof sheet - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof sheet, and more particularly to a waterproof sheet using ethylene-.alpha.-olefin rubber used for waterproofing of buildings, floors, walls or peripheral walls of subways, reservoirs and the like.

[0002]

2. Description of the Related Art Polyethylene, polypropylene, ethylene-vinyl acetate (EV
A sheet made of a polyolefin resin such as A), or a resin obtained by blending the above resin with a partially or completely crosslinked monoolefin copolymer rubber,
Those that have been given heat resistance and impact resilience are drawing attention.

For example, a thermoplastic elastomer obtained by dynamically heat-treating a monoolefin copolymer rubber and a polyolefin plastic in advance and partially cross-linking the same has a density of 0.910-.
A waterproof sheet formed by mixing 0.9408 g / cm ^{3 of} an ethylene polymer into a sheet is disclosed in JP-A-59-18741.

This type of waterproof sheet not only has excellent physical properties such as tensile strength, tear strength, breaking elongation, etc., but also has excellent adhesiveness and flexibility, so that it can be easily bonded and has weather resistance. It is suitable for construction or civil engineering work due to its excellent properties.

[0005]

However, such a waterproof sheet has a large coefficient of thermal expansion due to the crystalline nature of the polyolefin resin and a small stress during deformation. Therefore, since the sheet constructed in the summer is laid in a softened and expanded state, there is a problem that it contracts in the winter and its end comes off the fixing tool, and the buttock is tense and receives excessive stress. Occurred.

On the other hand, when the waterproof sheet is applied in winter, the sheet is laid in a hardened and contracted state, so that there is a problem in that it expands and wrinkles in the summer to deteriorate the appearance. .

Furthermore, in the method of joining the thermoplastic waterproof sheets as described above, hot air is blown to the lap portion of the waterproof sheet to melt the sheet surface, and then the lap portion is pressure-bonded and cooled. In this heat fusion method, the sheet is partially melted and thermoplasticized while pressing another sheet, so that the thickness of the sheet in the lap portion is reduced, and as a result, tensile stress is applied to the boundary portion of the joint portion. There was a problem of concentrating and disconnecting from this part.

Moreover, the thermoplastic sheet is sagged during the heat-sealing operation, and is easily deformed by an external force such as wind.
It was difficult to displace and lap joint accurately.

The present invention solves such a problem by improving the heat-sealing property, sufficiently maintaining the strength in the vicinity of the boundary in the bonded portion after the heat-sealing, and facilitating the bonding work. An object is to provide a waterproof sheet that can be implemented.

[0010]

The waterproof sheet according to the present invention comprises two ethylene-α-olefin rubber layers, one of which has a smaller degree of crosslinking than the other rubber layer, and It has a structure in which a reinforcing fiber member is embedded in rubber.

Of course, the reinforcing fiber member may be embedded between two layers of rubber or in at least one rubber.

That is, the waterproof sheet is a composite having at least three layers, and two of the ethylene-α-olefin rubber layers have different degrees of cross-linking. When the rheometer curve of the unvulcanized product of the layer is obtained, it is said that there is a clear difference in torque value between the two rubber layers. Specifically, an ethylene-α-olefin unvulcanized rubber layer having a high crosslinking rate or a large amount of a crosslinking agent and a low crosslinking rate or an ethylene-α-olefin uncrosslinked rubber layer having a low amount of a crosslinking agent Is vulcanized.

[0013]

In the waterproof sheet of the present invention, by providing the ethylene-α-olefin rubber layers having different degrees of cross-linking, the rubber layer having a low degree of cross-linking easily melts even when the sheets are stacked and heat-sealed. As a result, the rubber layer having a high degree of cross-linking is easily fused by heat. However, in the present invention, since the reinforcing fiber member is interposed, even if the sheet at the joint portion plastically flows and the sheet thickness decreases, and stress concentrates near the boundary of the joint portion, it is cut from this portion. There is nothing to do. Moreover, since the reinforcing fiber member can impart rigidity to the sheet at the joint portion and prevent the sheet from sagging, the sheet joining operation can be easily performed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

1 and 2 are cross-sectional views of a waterproof sheet according to the present invention, wherein the waterproof sheet 1 is ethylene-α having a high degree of crosslinking.
It is composed of three layers of an olefin rubber layer 2, a reinforcing fiber member 4 and an ethylene-α olefin rubber layer 3 having a low degree of crosslinking.

Among them, the reinforcing fiber member 4 is interposed between the ethylene-α-olefin rubber layer 2 having a high degree of crosslinking and the ethylene-α-olefin rubber layer 3 having a low degree of crosslinking, as shown in FIG. There is.

As shown in FIG. 2, the reinforcing fiber member 4 has an ethylene-α-olefin rubber layer 3 having a low degree of crosslinking.
It may be embedded inside. As a result, the rubber layer 3 having a low degree of cross-linking does not easily sag even when subjected to hot air or the like, so that the joining operation can be easily performed.

The ethylene-α-olefin rubber layer 2,
3 is ethylene propylene to which a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, a tackifier, a flame retardant, a reinforcing agent, etc. have been added. If necessary, natural rubber, styrene butadiene rubber,
Butyl rubber, chloroprene rubber, etc. may be mixed.

The method of imparting a difference in the degree of crosslinking between the rubber layers 2 and 3 can be carried out mainly by selecting ethylene propylene rubber, a vulcanizing agent and a vulcanization aid.

The ethylene-α-olefin rubber used in the present invention is a copolymer of ethylene and α-olefin such as propylene, 1-butene, 1-pentene and 1-hexane, and most preferably ethylene propylene rubber. Is. This ethylene propylene rubber is a non-conjugated diene such as dicyclopentadiene, ethylidene norbornene,
One type or two or more types of vinyl norbornene are copolymerized.

Therefore, when ethylene-α-olefin rubber layers having different degrees of crosslinking are used, the rubber layer 2 having a high degree of crosslinking is ethylene propylene rubber containing ethylidene norbornene, and the rubber layer 3 having a low degree of crosslinking is used. It is desirable to use ethylene propylene rubber containing dicyclopentadiene.

The ethylene propylene rubber has an ethylene content of 50 to 95% by weight and a non-conjugated diene content of 5 to 50 in terms of iodine value, but the rubber layer 3 having a particularly low degree of crosslinking has a high tensile strength. It is desirable to use ethylene propylene rubber having a high ethylene content of 70 to 95% by weight in order to have a high tear strength and a small elongation.

Further, as the ethylene-α olefin rubber, a mixture of ethylene propylene rubber (including non-conjugated diene) containing a polyolefin resin and a partially cross-linked vulcanizing agent and vulcanization aid is also included. Be done. This polyolefin resin is ethylene, propylene, 1-butene, or the like, and imparts fluidity to the rubber at the time of molding and facilitates heat fusion of the sheet joint portion at the time of construction.

The addition amount of the rubber component and the polyolefin resin is 90 to 10 parts by weight of the polyolefin resin to 10 to 90 parts by weight of the rubber component, preferably 20 to 80 parts of the rubber component.
It is 80 to 20 parts by weight of the polyolefin resin with respect to parts by weight. If the rubber component is less than 10 parts by weight, the properties of the polyolefin resin dominate, resulting in lack of flexibility.
Further, when the rubber component is 90 parts by weight or more, the heat fusion property becomes poor.

Examples of the vulcanizing agent used for the ethylene-α-olefin rubber include sulfur type, P-quinone dioxime (GHF) type and resin type such as olefin type, phenol type and xylene type. Generally sulfur-based,
It is a GHF system.

Further, the vulcanization aid is mainly a vulcanization accelerator, and tetramethylthiuram monosulfide (TMT) is used.
M), dipentamethylene thiuram tetrasulfide (DPTT), lead peroxide, trimene base, and other known vulcanization accelerators are included. When the vulcanization agent is a sulfur-based vulcanization accelerator, for example, zinc di-n-butyl is used. Thiocarbamate (ZnBDC) and dipentamethylene thiuram tetrasulfide (DPTT) are preferred.

The blending of the ethylene-α-olefin rubber includes a rubber component or a mixture 1 of a rubber component and a resin.
The proportion of the vulcanizing agent is 0.3 to 6 parts by weight, and the vulcanization aid is 0.1 to 10 parts by weight with respect to 00 parts by weight.

These are stearic acid, ZnO, carbon black, inorganic pigments, organic pigments, inorganic fillers, tackifiers, which are commonly used in rubber compounding, in addition to vulcanizing agents and vulcanization aids.
The softening agent is appropriately mixed and blended as necessary.

The above rubber component, a vulcanizing agent, a vulcanization aid and other fillers are mixed with a conventionally known kneading device such as a Banbury mixer, an internal mixer, a kneader or the like at a temperature not lower than the melting point of the polyolefin resin for about 1 to 15 minutes. The materials are melt-mixed to some extent, but the order of mixing is not particularly limited.

The mixture thus obtained can be formed into a sheet by molding with a calendar roll or an extruder for resin or rubber.

The reinforcing fiber member 4 used in the present invention has a thickness of about 0.05 to 0.50 mm, and is made of inorganic fibers such as glass fiber and carbon fiber, or polyester, polyamide, polyolefin, polyvinyl alcohol, An aramid or the like is made of an organic fiber and may be a woven fabric or a non-woven fabric.

As the method of manufacturing the waterproof sheet of the present invention, for example, first, the ethylene-α-olefin rubber layer 2 having a high degree of crosslinking is used.
And the ethylene-α-olefin rubber layer 3 having a low degree of cross-linking, the reinforcing fiber member 4 is interposed to perform pressure lamination, and this is installed on a conveyor belt and introduced into a vulcanization can while running. A method of vulcanizing, or laminating the reinforcing fiber member 4 to one of the rubber layers extruded by pressure, and then simply laminating another rubber layer,
A method of continuously vulcanizing this with the vulcanization can, a method of continuously vulcanizing this with the vulcanization can while interposing the reinforcing fiber member 4 between the extruded rubber layers 2 and 3. There is.

As described above, the waterproof sheet of the present invention has excellent heat-sealing property and easy joining work.
This will be described in detail with reference to FIG. FIG. 3 is a cross-sectional view of the joining portion of the waterproof sheet. In this joining work, hot air between the lap portions of the sheets is blown to positively melt the surface of the rubber layer 3 having a low degree of cross-linking, and then another By press-bonding with the sheet, the ethylene-α-olefin rubber layer 3 having a low degree of crosslinking and the ethylene-α-olefin rubber layer 2 having a high degree of crosslinking are easily joined. The rubber layer 3 having a low degree of cross-linking is more excellent in heat fusion property if the ethylene content is increased, for example.

Even if the heated rubber layer 3 having a low degree of cross-linking is melted during the above-mentioned work, since the reinforcing fiber member 4 is interposed in the waterproof sheet 1, the waterproof sheet 1 may be sagged. It also reduces deformation. Therefore, even if the joint portion receives an external force such as wind, the waterproof sheet itself is less likely to be deformed or displaced, and the sheets can be reliably joined together in the subsequent crimping work. Furthermore, even if the thickness of the sheet at the joint portion is reduced, the tensile strength does not decrease.

[0035]

As described above, the waterproof sheet of the present invention has the ethylene-α olefin rubber layers having different degrees of crosslinking,
And since it contains a reinforcing fiber member, the overlapping portion of the waterproof sheet can be easily joined by heat fusion,
Further, there is no reduction in strength in the vicinity of the joint portion, and it has the effect of preventing deformation of the waterproof sheet during heating and facilitating the joining operation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a waterproof sheet according to the present invention.

FIG. 2 is a cross-sectional view of another waterproof sheet according to the present invention.

FIG. 3 is a cross-sectional view of a joint portion of a waterproof sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waterproof sheet 2 Ethylene-alpha olefin rubber layer with high degree of cross-linking 3 Ethylene-alpha olefin rubber layer with low degree of cross-linking 4 Fiber material for reinforcement

Claims (3)

(57) [Scope of utility model registration request] 1. An ethylene-α-olefin rubber layer is provided in two layers, the degree of crosslinking of one rubber layer is made smaller than that of the other rubber layer, and the reinforcing fiber member is embedded in the rubber. Characteristic waterproof sheet. 2. A reinforcing fiber member comprising two layers of ethylene
The waterproof sheet according to claim 1, wherein the waterproof sheet is interposed between the α-olefin rubber layers. 3. The waterproof sheet according to claim 1, wherein the reinforcing fiber member is embedded in one of the two ethylene-α-olefin rubber layers.