JP3408695B2 - Rubber composition and high-strength adhesive tape - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vulcanized synthetic rubber-based waterproof sheet (hereinafter referred to as a vulcanized rubber sheet) used for impermeable water for civil engineering and construction such as a reservoir, an industrial waste treatment pond, a rooftop of a building. ) A rubber composition and a pressure-sensitive adhesive tape for a pressure-sensitive adhesive tape used for bonding each other.

[0002]

2. Description of the Related Art Conventionally, concrete and asphalt have been generally used as water-blocking materials used in reservoirs, etc., but recently, they have a large amount of strain, have good weather resistance, and are considered to be able to follow the movement of the ground. Sulfur rubber sheets have come into use. However, the vulcanized rubber sheet is limited in size in terms of manufacturing, and has a long length of about 250 m and a width of 1.0 to 5.0 m.
Is. Therefore, it is necessary to bond the vulcanized sheets to each other, and the bonding is currently performed on site. A number of methods have been proposed for the bonding of the joining portion, but there is no deciding factor such as this, a method of using an adhesive, a method of using an adhesive unvulcanized tape, or a method having both of them. Has been adopted.

Among these, in the method of using an adhesive, if there is unevenness when the adhesive is applied to the joint portion, the adhesive force also becomes uneven. Further, there is a drawback in that the adhesive force and the adhesive state are greatly influenced by the method of taking the drying time. on the other hand,
In the method using the adhesive non-vulcanized rubber tape, the vulcanized rubber sheet is heated from above and below at a temperature of 150 to 200 ° C. and pressure 1
The tape was vulcanized by applying a pressure of 00 to 200 kgf / cm ² . In this case, it is necessary to bring a special vulcanizing device to the construction site, and in order to obtain a high-strength adhesive force, it is necessary to perform vulcanization sufficiently at high temperature and high pressure, and work efficiency is poor.

[0004]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional method, without using a vulcanizer or the like.
Provided are a rubber composition for a high-strength adhesive tape and a high-strength adhesive tape for achieving water barrier by bonding an adhesive tape to a joint portion of a vulcanized rubber sheet.

[0005]

That is, the object of the present invention is to provide a partially crosslinked butyl rubber (A) and a general butyl rubber not partially crosslinked (B), a vulcanizing agent, a vulcanization accelerator, an adhesive and a softening agent. And the weight ratio A / B of (A) and (B) is 9
It is 5/5 to 5/95, and the penetration measured according to JIS-K-2207 at a load of 100 g and a temperature of 20 ° C. is 70.
It is intended to provide a rubber composition for a high-strength adhesive tape of 100 to 100 and a high-strength adhesive tape.

In the present invention, a partially crosslinked butyl rubber,
The presence of adhesives, softeners, etc., can be confirmed by the initial adhesive strength of 1 to 3 when the adhesive tape is attached to the joint portion of the vulcanized rubber sheet.
It contributes to a strong bond at kgf / 25 mm, and the presence of vulcanizing agents, vulcanization accelerators, etc. causes interfacial peeling between the vulcanized rubber sheet and the adhesive tape by further promoting the crosslinking degree of butyl rubber. No, more solid (6-8kg
f / 25 mm).

The partially crosslinked butyl rubber of the present invention has a degree of partial crosslinking of 25 to 80%, preferably 30 to 75%, but a commercially available partially crosslinked butyl rubber can be used. The degree of partial cross-linking is 30 after immersing the partially cross-linked butyl rubber in cyclohexane at 30 ° C. for 48 hours.
The mixture was filtered using a 0 mesh screen, the filtrate was dried to calculate the elution amount to cyclohexane, and the remainder obtained by subtracting this was expressed as a percentage [100- (30
Elution amount (%) into cyclohexane at 0 ° C.]]. As the partially crosslinked butyl rubber of the present invention, those having a Mooney viscosity ML _{1 + 8} 125 ° C. of 50 to 80 are preferably used. The general non-crosslinked butyl rubber (B) of the present invention is not particularly limited as long as it is a butyl rubber other than the partially crosslinked butyl rubber.

The A / B blending ratio of the partially cross-linked butyl rubber (A) and the general non-cross-linked butyl rubber (B) is such that the tape shape stability during high-strength adhesive tape molding and the bonding to a vulcanized rubber sheet. 95/5 to obtain high adhesive strength without peeling at the initial adhesive force and interfacial peeling
5/95, preferably 70/30 to 30/70.
When A / B is 0/100 to less than 5/95, the initial adhesive strength is low, and A / B is greater than 95/5 and 10
When it is 0/0 or less, the tape shape stability is impaired.

The vulcanizing agent used in the present invention is a sulfur-based compound comprising sulfur, a phosphorus-containing polysulfide, a sulfur-containing compound such as sulfur chloride, or an oxime-based compound such as p-quinonedioxime or p-p-dibenzoylquinonedioxime. Further, there are organic peroxides such as α-cumyl hydroperoxide, methyl ethyl ketone peroxide, acetylacetone peroxide, t-butyl hydroperoxide and t-butyl peroxybenzoate. The vulcanizing agents may be used alone or in combination of two or more. The amount of the vulcanizing agent used is not particularly limited as long as it further promotes the degree of crosslinking of butyl rubber, but is usually 0.5 to 100 parts by weight of the total rubber of (A) and (B). 5 parts by weight is suitable.

Examples of the vulcanization accelerator used in the present invention include thiuram compounds such as tetramethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylene thiuram tetrasulfide, 2-mercaptobenzothiazole,
Examples thereof include thiazoles such as dibenzothiazyl disulfide, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, dithiocarbamate salts such as zinc dibutyldithiocarbamate, and aldehyde amines such as n-butyraldehyde aniline. The vulcanization accelerators may be used alone or in combination of two or more, and the amount of the vulcanization accelerator may be such that the crosslinking of the butyl rubber is further promoted. 0.5 to 10 parts by weight is suitable for each part.

The high-strength adhesive tape of the present invention is sandwiched between joints of a vulcanized rubber sheet, and the adhesive strength is used to bond them together, followed by natural vulcanization without using a vulcanizing device. The required adhesive strength can be obtained.

The vulcanized rubber sheet used for the waterproof sheet is, for example, a commonly used ethylene propylene rubber, butyl rubber, a blend of ethylene propylene rubber and butyl rubber, or a blend of ethylene propylene rubber and styrene butadiene rubber. There are vulcanized rubber sheets such as, but the high-strength adhesive tape of the present invention can be applied to any of these vulcanized rubber sheets, particularly ethylene propylene rubber, or ethylene propylene rubber and butyl rubber from the viewpoint of water-blocking effect. It can be suitably used for a vulcanized rubber sheet of a blend with.

On the other hand, dust, sand, foreign matter, etc. may adhere to the joint portion of the vulcanized rubber sheet, and the surface thereof is not always smooth. From the viewpoint of improving the surface conformability to a vulcanized rubber sheet, the surface following property, and the workability of laminating in the field and the so-called sagging prevention of the high-strength adhesive tape, the penetration of the high-strength adhesive tape of the present invention is 70-100 by blending and mixing the adhesive agent, the softening agent, and the like,
It is preferably adjusted to 80 to 90. The needle penetration is JI
Load 100g, temperature 20 ° C according to SK-2207
It is the value measured under the condition of.

The adhesive used in the present invention includes coumarone-based resin, phenol-based resin, terpene-based resin, phenol
There is an adhesive such as formaldehyde resin. One or more kinds of the pressure-sensitive adhesives are used in combination, and the amount of the pressure-sensitive adhesives is usually appropriate to be 50 to 150 parts by weight based on 100 parts by weight of the total of the rubbers (A) and (B). .

Examples of the softening agent used in the present invention include process oil, liquid polybutene, liquid polyisobutylene, liquid paraffin, and other petroleum-based high boiling point compounds. One or more softeners may be used in combination, and the amount of the softener used is usually 1 in total for the rubbers (A) and (B).
30 to 130 parts by weight is suitable for 100 parts by weight.
Further, in the high-strength adhesive tape of the present invention, general rubber chemicals such as carbon black, a filler, an antioxidant, a processing aid and the like are used as required for the purpose of cost reduction and other purposes.
For kneading the rubber composition of the present invention, a kneader, roll or the like which is commonly used in the rubber industry can be used. An extruder or the like can be used for tape molding.

[0016]

The present invention will be described in detail below with reference to examples. In the following description, parts represent parts by weight. Examples 1-9, Comparative Examples 1-6 Table 1 shows the formulations of Examples 1-9. Further, Table 2 shows Comparative Example 1
~ 6 is shown.

[0017]

[Table 1]

[0018]

[Table 2]

Each of the blends was prepared by kneading with a 3 liter kneader, and the penetration was JIS-K-22.
According to 07, it was measured at a load of 100 g and a temperature of 20 ° C.
The formulation is then 1 mm thick x 65 mm φ extruder.
It was extruded into a tape having a width of 40 mm. Tape shape stability is observed and evaluated for surface smoothness and dimensional stability,
The results are shown by the following symbols. ◎ Excellent ○ Good △ Slightly inferior × Bad The initial adhesive strength was evaluated by touch with the fingers, and the results are shown by the following symbols. ◎ Excellent ○ Good △ Slightly inferior × Bad In order to examine the adhesive strength after vulcanization of the adhesive tape when the vulcanized rubber sheet was adhered using the above adhesive tape, the following measurement was performed. First, between 1 mm thick × 25 mm wide ethylene propylene rubber vulcanized rubber sheets, 1 mm thick × 2
A test piece was prepared by sandwiching the pressure-sensitive adhesive tape having a width of 5 mm and crimping it, and then proceeding with crosslinking in an oven at 80 ° C.
After taking out to room temperature, the autograph made by Shimadzu has a pulling speed of
The T peel strength was measured under conditions of mm / min and 20 ° C.

Table 3 shows the evaluation results of Examples 1 to 9. Table 4 shows the evaluation results of Comparative Examples 1 to 6.

[0021]

[Table 3]

[0022]

[Table 4]

Comparative Example 1 in which the rubber composition is not within the scope of the present invention
In Comparative Examples 1 to 3, Comparative Example 1 has high initial adhesive strength and adhesive strength, but poor tape shape stability. In addition, Comparative Examples 2 and 3
Has low adhesive strength. Although the composition of the rubber is within the range of the present invention, Comparative Example 4 in which the penetration is out of the range of the present invention has a low initial adhesive force, is likely to undergo interfacial peeling, and has a low adhesive strength. In Comparative Examples 5 and 6 in which the composition of the rubber is not within the range of the present invention and the penetration is outside the range of the present invention, the initial adhesive force is low, the interface is easily peeled off, and the adhesive strength is low. In Examples 1, 4, and 7 using butyl rubber having a crosslinking degree of 30%, the crosslinking degree of 50%, 7
The initial adhesive strength was lower than that of the other examples using 5% butyl rubber, but after 10 days, the adhesive strength was the same as that of the other examples.

[0024]

INDUSTRIAL APPLICABILITY The present invention is changed to a method of adhering a vulcanized rubber sheet with an adhesive or a method of adhering an unvulcanized rubber tape using a vulcanizing device for the purpose of blocking water. By blending a partially cross-linked butyl rubber and a normal butyl rubber into the joint part of the sheet, and attaching an adhesive tape containing a vulcanizing agent, a vulcanization accelerator, an adhesive, and a softening agent, it is possible to have an initial adhesive force. At the same time, the present invention provides a rubber composition for a high-strength adhesive tape and a high-strength adhesive tape for achieving water-blocking by further advancing the degree of cross-linking and further strongly adhering. By using the high-strength adhesive tape of the present invention, the work efficiency is higher than that of the conventional method, the work environment is not polluted, and the handling is easy, and the industrial value is high.

Front page continuation (72) Inventor Shiro Matsunaga 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Aomi Plant, Inc. Aomi Factory Co., Ltd. (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08L 23/00-23/36 C09J 123/00-123/36 C09J 7/00-7/04 C09J 5/00

Claims (5)

(57) [Claims] 1. A partially cross-linked butyl rubber (A) having a degree of partial cross-linking of 25 to 80%, a general butyl rubber (B) not partially cross-linked, a vulcanizing agent, a vulcanization accelerator, an adhesive and a softening agent. Including, the weight ratio A / B of (A) and (B) is 95/5 to 5 /
95 and a load of 10 according to JIS-K-2207
A rubber composition having a penetration of 70 to 100 measured at 0 g and a temperature of 20 ° C. 2. The rubber composition according to claim 1, wherein A / B is 70/30 to 30/70. 3. The rubber composition according to claim 1 or 2, wherein the penetration is 80 to 90. 4. Claim 1 or claim 2 or claim 3.
A high-strength adhesive tape comprising the rubber composition as described above. 5. A method of adhering a waterproof sheet, which comprises using the high-strength adhesive tape according to claim 4.