JPH0380830B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a water-swellable water-stop material, more specifically, a water-swellable water-stop material that has excellent low-temperature expansion properties, low hardness at low temperatures, and excellent low-temperature workability. It is related to. Water-stopping materials are widely used in civil engineering and construction work to stop water leaks by filling them into gaps where water leaks, such as cracks, fissures, and gaps in mortar, concrete construction, and water pipe connections. . BACKGROUND ART Conventionally, water-swellable compositions such as water-swellable compositions, such as superabsorbent resins, diene rubbers, vulcanizing agents, vulcanization accelerators, fillers, anti-aging agents, etc., have been vulcanized as water-stopping materials. Resin compositions that swell on contact with water have been developed, consisting of water-swellable compositions and non-swellable compositions such as diene rubbers, vulcanizing agents, vulcanization accelerators, fillers, etc. It has been proposed to stop water by combining a vulcanized product of a mixture of a compound, an anti-aging agent, etc. (Japanese Patent Laid-Open Nos. 57-108143 and 1982-135160). However, these proposals require a vulcanization process, which poses problems in the productivity of the water-stopping material, and in addition, the diene rubber is vulcanized and cannot be reused. be. Also known is a water-swellable composition in which a flexible thermoplastic synthetic resin such as an ethylene-vinyl acetate copolymer contains a highly water-absorbent resin (Japanese Patent Application Laid-open No. 3424/1983). However, water-swellable compositions using thermoplastic synthetic resins such as ethylene-vinyl acetate copolymers and flexible vinyl chloride resins have a large temperature dependence, have a narrow usable temperature range, and have particularly poor low-temperature workability. There are problems such as low expansion at high and low temperatures. Problems to be Solved by the Invention The inventors of the present invention aimed to solve these problems and provide a water-swellable waterproof material that has excellent low-temperature workability and low-temperature expansion properties and does not require a vulcanization process. As a result of extensive research, we have created a molded product using chlorinated polyethylene and polyisobutylene in a predetermined ratio as water-insoluble polymer substances, and adding a super absorbent resin with the required water absorption capacity in a predetermined ratio. However, the present invention has been completed based on this finding. Means for Solving the Problems That is, the present invention provides (A) chlorinated polyethylene 30
100 parts by weight of a water-insoluble polymer composition consisting of ~95% by weight and 70-5% by weight of polyisobutylene and (B) a super absorbent resin 15 having a water absorption capacity of 50 to 1000 times its own weight.
It is formed by molding a mixture containing ~100 parts by weight,
The present invention also provides a water-swellable waterproofing material, which has a hardness of less than 65 at a temperature of 2°C. The water-insoluble polymer substance used in the water-stopping material of the present invention is a combination of chlorinated polyethylene and polyisobutylene. As the chlorinated polyethylene, a wide range of molecular weights from 20,000 to 200,000 can be used, but chlorine A content in the range of 25 to 45% by weight, generally 30 to 40% by weight is preferred in terms of rubbery properties, and a crystallinity of 10% or less is preferred in terms of flexibility. On the other hand, polyisobutylene has a molecular weight of 10
A wide range of numbers from 10,000 to 5,000,000 can be used. In the present invention, the weight ratio of the chlorinated polyethylene and polyisobutylene is 3:7 to 3:7.
The ratio is selected from 9.5:0.5, preferably from 5:5 to 8:2. If the ratio of chlorinated polyethylene to polyisobutylene is less than the above range, the moldability will be poor, and the obtained water stop material will be highly adhesive and sticky, and the strength upon expansion will be low; on the other hand, if it is more than the above range, The water-stopping material has poor low-temperature expansion properties and high hardness, resulting in poor workability. As the super absorbent resin used for water stopping of the present invention,
For example, commercially available starch-polyacrylate superabsorbent resins, crosslinked polyacrylates obtained by reverse phase polymerization in organic solvents, basic substances such as vinyl alcohol copolymers and maleic anhydride copolymers. Examples include superabsorbent resins obtained by crosslinking reaction products with Among these, considering the water absorbency and durability of the resulting water-stopping material, we have added 1 carboxyl group or a group that can be converted to a carboxyl group in the molecule.
A superabsorbent resin obtained by crosslinking a polymer containing one or two α,β-unsaturated compounds as a monomer component using a crosslinking agent is suitable. The superabsorbent resin desirably has a water absorption capacity of 50 to 1000 times, preferably 100 to 800 times, its own weight. If the water absorption capacity is less than 50 times, the obtained water stop material will have insufficient swelling properties, and if it exceeds 1000 times, the strength upon swelling will be insufficient. In the water stop material of the present invention, the superabsorbent resin is preferably 15 to 100 parts by weight, based on 100 parts by weight of the water-insoluble polymer composition comprising a combination of chlorinated polyethylene and polyisobutylene. 20～
Use in a range of 60 parts by weight. If this amount is less than 15 parts by weight, the resulting waterproof material will have poor low-temperature expansion properties, and
If it exceeds 100 parts by weight, the expansion ratio becomes too large, resulting in low strength and high hardness, resulting in poor workability. Next, to explain one example of a suitable manufacturing method for the water stop material of the present invention, first, chlorinated polyethylene,
A predetermined amount of polyisobutylene and super absorbent resin are blended, and if necessary, additional ingredients such as stabilizers, ultraviolet absorbers, lubricants, fillers, flame retardants, antistatic agents, foaming agents, antifungal agents, and colorants are added. After mixing and sufficiently kneading, the water-stopping material can be obtained by extrusion molding or press molding the obtained mixture. The water stop material obtained in this way is JIS K6301
Accordingly, from the viewpoint of low-temperature workability, it is necessary that the hardness according to the spring type hardness test type A (JIS A hardness) at a temperature of 2° C. be less than 65. Those with a hardness of 65 or more have extremely poor low-temperature workability. Effects of the Invention The water-swellable waterproof material of the present invention has excellent low-temperature expansion properties, good strength upon expansion, low hardness at low temperatures, and excellent low-temperature workability. Furthermore, since no vulcanization step is required to manufacture the water stop material, productivity is also good. This water-stopping material is used to effectively prevent water leakage during civil engineering and construction work, for example, by filling gaps such as shield segment joint surfaces, joints of humid pipes and prefabricated culvert boxes, and pouring joints of concrete structures. used.
It can also be used as a water retaining material for agriculture, forestry, and horticulture. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, low-temperature expansion property, strength at room temperature expansion, and low-temperature workability were evaluated according to the following methods. (1) Low-temperature expansion After immersing the sample in still water at 2℃ for 3 days,
Weight expansion ratio (weight after immersion/weight before immersion)
The value was evaluated as ○ if the value was 2.0 or more, and × if the value was less than 2.0. (2) Strength when expanded at room temperature The sample is immersed in still water at 18℃, and the tensile strength (Kg/cm ² ) when the expansion reaches equilibrium is determined. If the value is 1.5Kg/cm ² or more, it is marked as ○. Less than 1.5 Kg/cm ² was evaluated as ×. (3) Low-temperature workability The hardness at a temperature of 2°C was determined by the spring type hardness test type A test method according to JIS K6301, and the value was evaluated as ○ if the value was less than 65, and × if the value was 65 or more. Examples and Comparative Examples A resin composition having a composition as shown in the attached table,
1.5 parts by weight of tin-based stabilizer [manufactured by Nitto Kasei Co., Ltd., TVS #8813] per 100 parts by weight of chlorinated polyethylene;
Total of chlorinated polyethylene and polyisobutylene
2.0 parts by weight of titanium oxide and 0.2 parts by weight per 100 parts by weight and blue pigment [manufactured by Dainichiseika Chemical Co., Ltd., PV]
0171BLUE] was added, and this mixture was kneaded with a roll heated to 120°C, and then press-molded at 140°C to create a water-stopping material sample with length and width of 20 mm and thickness of 2 mm. Each sample was evaluated for low temperature expansion properties, strength at room temperature expansion, and low temperature workability. The results are shown in the table. The following superabsorbent resins, chlorinated polyethylene, and polyisobutylene were used. Super absorbent resin A: maleic anhydride/isobutylene copolymer [manufactured by Kuraray Isoprene Chemical Co., Ltd., Kuraray KI Gel]
201, maximum water absorption: 200 times its own weight] B: Acrylic acid/vinyl alcohol copolymer [manufactured by Sumitomo Chemical Co., Ltd., Sumikagel SP-520, maximum water absorption: 600 times its own weight] Chlorinated polyethylene A: Chlorine Content 35% by weight, specific gravity 1.15, hardness (Short A) 55 [Osaka Soda Co., Ltd., Daiso Raku RA-
135] B: Chlorine content 35% by weight, specific gravity 1.16, hardness (Shore A) 70 [Osaka Soda Co., Ltd., Daiso Raku G-
235] Polyisobutylene A: Viscosity average molecular weight 990,000 [manufactured by Exxon Chemical Co., Ltd., Vistanetx MML-80] B: Viscosity average molecular weight 2.1 million [manufactured by Exxon Chemical Co., Ltd.,
Vistanetx MML-140〕

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Claims (1)

[Claims] 1 (A) 100 parts by weight of a water-insoluble polymer composition consisting of 30 to 95% by weight of chlorinated polyethylene and 70 to 5% by weight of polyisobutylene, and (B) a polymer composition having a water absorption capacity of 50 to 1000 times its own weight. 1. A water-swellable water stop material, characterized in that it is formed by molding a mixture containing 15 to 100 parts by weight of a water-absorbing resin, and has a hardness of less than 65 at a temperature of 2°C.