JPH0353348B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-absorbing expandable sealing material,
More specifically, by using an organic water absorbing swelling agent and an inorganic water absorbing swelling agent together, without impairing the characteristics such as adhesiveness and conformability of the non-vulcanized butyl sealing material,
This invention relates to a water-absorbing and expanding sealing material that is made of non-vulcanized rubber and exhibits a high expansion rate. Water-absorbing and expanding sealants are usually used between concrete structures, between metal structures, or between concrete or metal structures and ready-mixed concrete, and expand by absorbing rainwater, groundwater, etc. , which has the advantage of making water stoppage even more effective, has recently been used in many places. Conventionally, urethane-based sealants have been known as vulcanized sealants that can be applied to the above applications, but in addition to lacking adhesiveness and plasticity, they are also cross-linked, so they inevitably have It is impossible to integrate them when stacking them, and they have drawbacks such as being difficult to install in areas with complex shapes, being easily hydrolyzed, and the polymer itself absorbing water, resulting in decreased performance. . In addition, butyl rubber and thermoplastic rubber are known as non-vulcanized sealing materials, but these have the disadvantage of requiring high structural dimensional accuracy and construction accuracy due to their low water absorption expansion coefficients. have.
In other words, at the joints of structures where the sealing material is used, gaps between the structures inevitably occur due to the dimensional accuracy, construction accuracy, construction conditions, etc. of the structures, but the gaps between the structures are The distance between the structures is not uniform depending on the joint location, and may actually be larger than the expected distance between the structures. Accordingly, there is a drawback that the sealing material may be used beyond its performance limit. The purpose of the present invention is to take advantage of the adhesion, conformability, and durability that are the characteristics of conventionally widely used non-vulcanized butyl rubber sealing materials, and also to exhibit high water absorption and expansion properties, thereby eliminating the above-mentioned drawbacks. That is. The water-expandable sealing material of the present invention that satisfies these objectives has the following features: (a) a non-vulcanized butyl rubber base containing one or more raw rubbers of butyl rubber, recycled butyl rubber, and polyisobutylene; 100 parts by weight of a non-vulcanized butyl rubber base, which is a rubber base containing 50% by weight or more, (b) 0.01 to 10 parts by weight of an organic water-absorbing and swelling agent per 100 parts by weight of the rubber base, and (c)
A non-vulcanized butyl-based non-vulcanized butyl-based material comprising: 20 to 150 parts by weight of an inorganic water-absorbing and swelling agent per 100 parts by weight of the rubber base; and (d) 10 to 200 parts by weight of a plasticity modifier per 100 parts by weight of the rubber base. A rubber sealing material characterized in that the total amount of the organic water-absorbing and swelling agent (b) and inorganic water-absorbing and swelling agent (c) components is contained in the total sealing material in an amount of 5 to 50% by weight. . According to the present invention, a sealing material having high water-absorbing and swelling properties can be obtained by adding specific amounts of an organic water-absorbing swelling agent and an inorganic water-absorbing swelling agent, and the obtained sealing material is a non-vulcanized butyl rubber sealing material. It has the characteristics of adhesion, followability, and durability, and also has 100 to 200%
Since it shows a water absorption volume change rate of , it can also be applied to locations with larger gaps between structures. In addition, the polymer itself of the water-absorbing expansion sealing material absorbs almost no water and is mainly composed of chemically stable butyl rubber.
No deterioration such as hydrolysis occurs. Organic and inorganic water-absorbing and expanding agents uniformly dispersed in the polymer undergo so-called crystallization and change in volume, making it more stable than water-absorbing and expanding sealing materials in which the polymer itself expands by absorbing water. The present invention will be explained in detail below. The non-vulcanized butyl rubber base used in the present invention is a rubber base containing 50% by weight or more of one or more of butyl rubber, butyl recycled rubber, and raw rubber of polyisobutylene. Other polymers used as rubber bases include styrene butadiene copolymer, styrene butadiene block copolymer, styrene isoprene block copolymer, polyisoprene, acrylonitrile butadiene copolymer, polychloroprene ethylene propylene copolymer, Ethylene propylene diene terpolymer, polybutadiene,
Examples include atactic polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, and ethylene-vinyl acetate copolymers. The non-vulcanized butyl rubber base used in the present invention is a factor that greatly influences the degree of water absorption expansion, durability, and strength after water absorption, and may be used alone or in combination with the plasticity modifier described below. Preferably, a non-vulcanized butyl rubber base is made from several types of polymers and finely adjusted using a plasticity modifier, and the non-vulcanized butyl rubber base is made at 70% by weight.
That's all for now. Furthermore, it is desirable to control the plasticity, roll workability, extrusion workability, etc. by controlling the other polymers used as the rubber base. Next, as organic water-absorbing and swelling agents, those generally used as super absorbent resins include polyacrylate-based, modified polyvinyl alcohol-based,
There are grafted starch types, vinyl alcohol-acrylate copolymers, cellulose types, etc., but all of them are effective in small amounts when used alone or in combination.
It is necessary to uniformly disperse it in the rubber base as a fine powder smaller than a mesh size. If a powder of 100 meshes or more is used, it will not be sufficiently dispersed and elution will occur, leading to problems with durability. As means for uniformly dispersing, a method of simply dispersing in oil, a method of using in combination with a surfactant, a method of using in combination with a silane coupling agent, etc. are used alone or in combination. In the present invention, the organic water-absorbing and swelling agent is used in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the non-vulcanized butyl rubber base. When less than 0.5 parts by weight of an organic water-absorbing and swelling agent is added, precision in manufacturing control is required and variations between lots are likely to occur, while when more than 5 parts by weight is added, there is a problem of elution and the durability deteriorates. White carbon (SiO ₂ ) and bentonite are used as inorganic water absorption and expansion agents. In general, white carbon (SiO ₂ ) has a fast water absorption and expansion rate, while bentonite tends to have a slow water absorption and expansion rate. A water-absorbing and expanding sealing material having an arbitrary expansion degree and expansion rate can be obtained by adjusting the above-mentioned organic expansion agent and inorganic water-absorbing expansion agent in combination. In the present invention, the inorganic water absorbing and expanding material is used in an amount of 30 to 80 parts by weight based on 100 parts by weight of the non-vulcanized butyl rubber base. In addition, if white carbon alone is used in excess of 40 parts by weight per 100 parts by weight of the non-vulcanized butyl rubber base, the alkali resistance will drop significantly, so white carbon should be used alone as an inorganic water-absorbing and expanding material. In such cases, the amount must be 40 parts by weight or less per 100 parts by weight of the non-vulcanized butyl rubber base. In addition, when bentonite is used as the main component of an inorganic water-absorbing and swelling agent, a non-vulcanized butyl rubber base is used.
If 120 parts by weight or more of bentonite is added to 100 parts by weight, the elution of bentonite will be significant.
Since the expansion rate retention rate after drying and wetting cycles decreases, the amount must be 120 parts by weight or less. Plasticity modifiers include synthetic plasticizers such as esters, phosphates, paraffin derivatives, polyethers, mineral oil softeners, vegetable oil softeners and tackifiers commonly used in the rubber industry and plastic industry. A filler is used. The main purpose of the plasticity modifier used here is to finely adjust the swelling degree and to improve and adjust the durability against repeated drying and wetting, and examples of its details are as follows. Examples of synthetic plasticizers used include dioctyl phthalate, tricresyl phosphate, dibutyl diglycol adipate, and chlorinated paraffin. Examples of rubber softeners include paraffin oil, naphthenic oil, aromatic oil, liquid polybutadiene, liquefied polychloroprene, liquid polyisoprene, liquid polyisobutylene-isoprene copolymer, low molecular weight olefin polymer, liquid polybutene, Depolymerized rubber, castor oil, tall oil, etc. are used. Examples of tackifiers are natural resin-based rosin,
There are rosin derivatives, terpene resins, and terpene phenol resins, and aliphatic, aromatic, alicyclic, copolymers, coumaron-indene petroleum resins, phenolic resins, xylene resins, etc. are used as synthetic resins. . Fillers include calcium carbonate, barium sulfate, talc, clay, zinc oxide, magnesium oxide, aluminum hydroxide, asbestos, mica,
Basic magnesium carbonate, carbon, etc. are used. The amounts used are based on non-vulcanized butyl rubber.
The amount is 40 to 100 parts by weight per 100 parts by weight. The method for manufacturing the sealing material of the present invention is not particularly limited. The kneading method is carried out by masticating a non-vulcanized butyl rubber base, and then adding and mixing an organic water-absorbing swelling agent, an inorganic water-absorbing swelling agent, and a plasticity modifier at once or in several batches. As the kneading machine, commonly used kneading machines such as rolls, banburys, kneaders, etc. can be used. Molding machines include extrusion molding machines, press molding machines,
Calendar molding machines etc. can be used to make strips, depending on the purpose.
It can be molded into various shapes such as sheets and rods. In addition, the construction can be easily carried out by pasting conventionally used non-vulcanized butyl adhesive tapes together and pressing them together on-site or by bonding them with an adhesive. The water-absorbing expandable sealing material obtained in this way is
It exhibits high expansibility with excellent adhesion, conformability, and durability, so overlapping parts can be easily integrated, and it can also be used between structures with large gaps, providing a more stable water stop. Demonstrates long-term performance. Therefore, the water-absorbing and expanding sealing material of the present invention can be used in seals between various structures in which conventional water-stopping materials are used, and can significantly improve the water-stopping performance of conventional water-stopping materials. . Next, the present invention will be explained using Examples 1 to 3 and Comparative Examples 1 to 7, but the present invention is not limited in any way by these Examples. [1] Preparation of sample A non-vulcanized butyl rubber base compounded according to the formulation shown in Table 1 was kneaded using an open roll, and then an organic water-absorbing swelling agent, an inorganic water-absorbing swelling agent, and a plasticity modifier were added. was added and kneaded using open rolls. Next, samples were prepared by extrusion molding into rectangular cross sections of 30 mm x 30 mm and 30 mm x 10 mm. For these samples with the composition shown in Table 1, the water absorption expansion rate and drying cyclic expansion rate retention rate were measured, the water pressure resistance test was conducted, and the state of the overlapped parts was examined.
Shown in the table. [2] Test method (1) Water absorption expansion rate Prepare a sample with sample dimensions of 3 mm x 30 mm x 30 mm, immerse the obtained sample in tap water for 7 days at room temperature, and calculate the water absorption expansion rate using the following formula. The rate was determined as the volume change rate. ΔV=(W ₂ −w ₂ )−(W ₁ −w ₁ )/W ₁ −w ₁ ×100 where ΔV: Water absorption expansion rate (%) W ₁ : Weight of sample in air before immersion in water (mg) W ₂ : Weight of the sample in air after immersion in water (mg) w ₁ : Weight of the sample in water before immersion in water (mg) w ₂ : Weight of the sample in water after immersion in water Weight (mg) (2) Wet and dry cyclic expansion rate retention A sample was prepared with sample dimensions of 3 mm x 30 mm x 30 mm, immersed in tap water at 50°C for 8 hours, and then placed in a dryer at 50°C. One cycle was drying for 16 hours, and 30 cycles were performed. The sample was immersed in tap water at 50℃ for 8 hours,
After drying at 50°C for 16 hours, the weight in air and weight in water was measured, and the swelling retention rate was calculated from the swelling degree at the 1st cycle and the swelling degree at the 30th cycle using the following formula. . Wet and dry repeated expansion rate retention rate (%) = Expansion rate at 30th cycle (%) / Expansion rate at 1st cycle (%) x 100 The expansion rates at 1st and 30th cycles are shown in Test Method 1 above. It was determined using the method. (3) Water pressure test A sample having a rectangular cross section of 30 mm x 10 mm prepared by the sample preparation method described above was pasted on one side of the sample contact surface of a water pressure test jig as shown in FIG. Next, a 12 mm thick spacer was set and the hydraulic test jig was clamped, and then the inside of the hydraulic test jig was filled with water and left to stand for 3 days. Next, the water pressure was increased in steps of 1.0 Kg/cm ² starting from 1.0 Kg/cm ² to check for leakage water pressure.
However, the pressurization time was 24 hours in each case. Furthermore, the hydraulic test jig was disassembled and the overlapping portion was checked. The water pressure test equipment used in the test is as shown in Figures 1A and B. 1 is a spacer,
2 is an upper lid, 3 is a bolt, 4 is a water-absorbing expandable sealing material, 5 is a hydraulic test jig main body, 6 is a water pressure outlet, 7 is a pressure gauge, 8 is a water pressure inlet, and 9 is a pump.

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[Table] Example 1 When a sample manufactured according to the above-mentioned sample preparation method using the formulation shown in Table 1 was tested according to the above-mentioned test method, the water absorption expansion rate was 120%, indicating that it was a non-vulcanized butyl-based It exhibited a high water absorption expansion rate that had never been seen before in a water absorption sealing material. The retention rate of expansion rate after repeated wet and dry cycles was 86%, and no decrease was observed after 9 cycles, indicating good durability. In the water pressure test, there was no water leakage for 24 hours at 6.0Kg/cm ² . When the sealing material was observed after the test, it was found that
The overlapped portion of the sealant was completely integrated. Comparative Examples 1 and 2 As shown in Table 1, cases in which (b) the amount of organic water-absorbing and swelling agent exceeds the upper limit and cases in which it is not added are shown in the formulation of Example 1 of the present invention. When a large amount, such as 5 parts by weight, of an organic water-absorbing swelling agent (Aquarik CA) was added, there was a problem in that the dry-wet cyclic expansion rate retention rate decreased significantly due to the elution of the organic water-absorbing swelling agent, resulting in a decrease in durability. On the other hand, when the above-mentioned organic water absorption and expansion agent was used in a small amount due to its lower limit of 0.5 parts by weight, the water absorption and expansion rate was low and did not meet the purpose of the present invention. Comparative Examples 3 and 4 As shown in Table 1, from the formulation of Example 1 of the present invention, (c) cases where the amount of inorganic water absorbing and swelling agent exceeds the upper limit and cases where it falls below the lower limit are shown. be. When a large amount of inorganic water-absorbing and swelling agent is used, the retention rate of the dry-wet cyclic expansion rate decreases significantly due to the elution of the inorganic water-absorbing and swelling agent, which causes problems in durability. On the other hand, when the inorganic water absorption and expansion agent was used in a small amount, the water absorption and expansion rate was low and did not meet the purpose of the present invention. Comparative Examples 5 and 6 As shown in Table 1, the results of tests were conducted for cases in which (d) the amount of plasticity modifier was outside the range of the formulation of Example 1 of the present invention. When the plasticity modifier was used in a large amount, the water absorption expansion rate decreased, and the dry/wet cyclic expansion rate retention rate also decreased. The degree of decrease also decreased at a nearly constant rate as the number of cycles increased, posing a problem in durability. On the other hand, when the amount of plasticity modifier is small, the workability of kneading, extrusion, etc. is poor, and it is not suitable for practical use. Comparative Example 7 As shown in Table 1, the results of tests were conducted for cases where the composition range of raw rubber based on non-vulcanized butyl rubber was outside the range of the composition of Example 1 of the present invention. If the non-vulcanized butyl rubber base contains less than 70% by weight of one or more of butyl rubber, butyl recycled rubber, and polyisobutylene, the dry/wet cyclic expansion retention rate will be poor. After the water pressure test, it was observed that the overlapped portions were not partially integrated, and the adhesiveness, which is a characteristic of non-vulcanized butyl rubber sealing materials, was impaired. Examples 2 to 3 In Tables 1 and 2, Examples 2 and 3 show some of the embodiments of the present invention due to the difference in water absorption and expansion speed, but both of them are based on the conventional non-vulcanized butyl It exhibits high water absorption and swelling properties not seen in rubber sealing materials, and also has a good dry/wet cyclic expansion retention rate, and the water pressure test was 6.0 kg/cm ² with no water leakage observed for 24 hours. Furthermore, the overlapping parts were completely integrated without impairing the characteristics of the non-vulcanized butyl rubber sealing material. Example 4 As shown in Table 1, the non-vulcanized butyl rubber base contains 80% by weight of the butyl rubber component, and the organic water absorption and swelling agent ACRIQ CA passes through 120 meshes, so the amount added is at the upper limit. It is close to. The total amount of inorganic water-absorbing and swelling agents is 80 parts by weight, which is the upper limit. The amount of plasticity modifier shown is close to the lower limit. When tested according to the above test method, the water absorption expansion rate was 190%, which was a high water absorption expansion rate that had not been previously seen for a non-vulcanized butyl rubber sealing material. The dry and wet cyclic expansion rate retention rate is also good, and the water pressure test is 6.0Kg/cm ²
No water leakage was observed for 24 hours. Furthermore, the overlapped portions were completely integrated, demonstrating the characteristics of a non-vulcanized butyl rubber sealing material. Example 5 As shown in Table 1, the non-vulcanized butyl rubber base contains 80% by weight of a butyl rubber component in the rubber base, and the organic water absorbing and swelling agent Sumikagel A-20 passes through 250 meshes. The amount is close to the upper limit. The total amount of inorganic water-absorbing and swelling agents is
The amount is 35 parts by weight, which is close to the lower limit amount. The plasticity modifier is shown in an amount close to the upper limit. When tested according to the test method described above, the water absorption expansion rate was 140%, which was a high water absorption expansion rate that had not been previously seen for non-vulcanized butyl rubber sealing materials. The retention rate of expansion rate after drying and wetting was also good, and the water pressure test was 6.0Kg/cm ² with no water leakage observed for 24 hours. Furthermore, the overlapped portions were completely integrated, demonstrating the characteristics of a non-vulcanized butyl rubber sealing material. Comparative Example 8 As shown in Table 1, the formulation is the same as in Example 5, but the organic water-absorbing and swelling agent Sumikagel A-20 is
An example using 80 mesh powder was shown. When tested according to the above test method, it was found that the dry/wet cyclic expansion rate retention was 52%, which caused a serious problem in durability. Moreover, FIG. 2 shows the water absorption and expansion rates of Examples 1 to 3, where the horizontal axis shows the number of days of immersion and the vertical axis shows the water absorption and expansion rate of change (%). When the amount of organic swelling agent and white carbon is large, the water absorption and expansion speed is fast.
As the amount of organic swelling agent was increased, the expansion rate became faster and showed a higher water absorption expansion rate. Increasing the amount of bentonite slows down the rate of water absorption and expansion, but it now shows a high water absorption and expansion rate. In other words, Figure 2 shows that it is possible to arbitrarily control the water absorption and expansion rate by using an organic water absorption and expansion agent together with an inorganic water absorption and expansion agent such as white carbon and bentonite. . Therefore, the present invention not only increases the water absorption expansion rate of a non-vulcanized butyl rubber-based water absorption sealing material, which could not be solved by conventional methods, but also improves the retention rate of the expansion rate in dry and wet cycles. Since we were able to completely integrate the overlapping parts of the structures, it is possible to fully accommodate the gaps between structures that are larger than expected due to the dimensional accuracy of the structures, construction accuracy, construction conditions, etc., and can be used for a long time. This enables a more complete water stoppage, and has great industrial utility value.

[Brief explanation of drawings]

FIG. 1A is a cross-sectional view of a water pressure testing apparatus used in the water pressure test of the sealing material of the present invention, FIG. 1B is a partial cross-sectional view showing details of the sample setting part of the apparatus shown in FIG. 1A, and FIG. The figure is a characteristic curve diagram of the water absorption expansion rate showing the relationship between the number of immersion days and the water absorption expansion rate of change. DESCRIPTION OF SYMBOLS 1...Spacer, 2...Upper lid, 3...Bolt, 4...Water-absorbing expandable sealing material, 5...Hydraulic pressure test jig body, 6...Water pressure outlet, 7...Pressure gauge, 8...
...Water pressure inlet, 9...pump.

Claims (1)

[Scope of Claims] 1 (a) The non-vulcanized butyl rubber base is a rubber base containing 50% by weight or more of one or more raw rubbers of butyl rubber, recycled butyl rubber, and polyisobutylene. 100 parts by weight of a non-vulcanized butyl rubber base, (b) 0.01 to 10 parts by weight of an organic water-absorbing and swelling agent per 100 parts by weight of the rubber base, and (c) 20 to 150 parts by weight per 100 parts by weight of the rubber base. (d) 10 to 200 parts by weight of a plasticity modifier based on 100 parts by weight of the rubber base, the non-vulcanized butyl rubber sealing material comprising: A water-absorbing and expanding sealing material, characterized in that the total amount of components (b) and inorganic water-absorbing and swelling agent (c) is 5 to 50% by weight in the total sealing material.