Complex water-sealing sealant

Abstract: A complex water-sealing sealant is produced by extruding and molding a non-water-swelling thermoplastic resin (A) and a water-swelling resin (C) obtained by kneading said non-water-swelling thermoplastic resin (A) and a water-swelling material (B).

Description: The present invention relates to a complex water-sealing sealant used in various civil engineering and construction works. As water-sealing sealants used for waterstop in various civil engineering and construction works, a complex water-sealing sealant comprising a water-swelling part and a non-water-swelling part has been used conventionally. When all of the constituted parts of the complex water-sealing sealant are made of rubbers, it is possible to produce a molding having reliable adhesion by extrusion molding. However, when the constituted parts thereof are made of different kinds, for example, rubbers and thermoplastic resins, extrusion molding cannot be conducted due to the insufficient adhesion. Therefore, it needs the help of an adhesive and the adhesive strength is inferior. The complex water-sealing sealant comprising a water-swelling part and a non-water-swelling part, which cannot be produced by extrusion molding as mentioned above, has such troubles that the production thereof is not so easy and the adhesive strength is inferior. On the other hand, in the case of a sheet pile made of resin, since waterstop is intended to either by injecting the water-swelling liquid to the joint portion or inserting the molding of water-swelling sealing sealant thereto, there is a disadvantage of increasing works. EP-A-0118998 discloses a watertight sealing material comprising a compression-resistant water-swelling rubber composition. The rubber composition comprises (a) a chloroprene rubber, (b) a highly water-absorptive resin, (c) a rubber polymer and (d) a metal oxide-based vulcanizing agent. EP-A-0055848 discloses a water-absorbing rubber composition comprising (a) a 1,3-diene rubber (e.g. a chloroprene rubber) and (b) a highly water-absorbing resin dispersed in said rubber. The object of the present invention is to provide an improved complex water-sealing sealant which solves the above-mentioned problems of the conventional complex water-sealing sealants, that is, to provide complex water-sealing sealant which can be molded by extrusion molding and which is combined with the high adhesive strength. The present invention has solved the above object by providing a complex water-sealing sealant comprising a non-water-swelling thermoplastic resin (A) being a polyvinyl chloride containing 100 to 200 parts by weight of a plasticizer based on 100 parts by weight of said polyvinyl chloride, and a water-swelling resin (C) obtained by kneating said non-water-swelling thermoplastic resin (A) and a water-swelling material (B) being a water-swelling urethane resin including prepolymer(s) having isocyanate groups, in which the content of terminal NCO groups amounts to 1 to 12%, obtained by the reaction of one or more polyether polyols represented by the following general formula and polyisocyanate; R[(OR 1 )n OH]p wherein R represents a polyhydric alcohol residue; (OR 1 )n represents a polyoxyalkylene chain comprising oxyalkylene groups each having an oxyethylene group and an alkylene group carrying three or four carbon atoms, provided that the content of the oxyethylene groups amounts to 20 to 100% of the total molecular weigh; n is a number corresponding to the degree of polymerization of the oxyalkylene groups and giving a hydroxyl group equivalent of 200 to 2500; and p is a number of 2 to 8, preferably 2 to 4, said complex water-sealing sealant being molded by the extrusion molding of said non-water swelling thermoplastic resin (A) and said water-swelling resin (C). The complex water-sealing sealant of the present invention is excellent in exhibiting the reliable waterstop of the water-swelling part, and has many advantages such that the non-water-swelling thermoplastic resin (A) and the water-swelling resin (C) are combined with the high adhesive strength by the extrusion molding and the process for production is easy. Fig. 1 is a section view illustrating a complex water-sealing board which is one example of the complex water-sealing sealants of the present invention. Fig. 2 is a section view illustrating a joint sealant which is one example of the complex water-sealing sealants of the present invention. Fig. 3 is a section view illustrating a sheet pile made of resin which is one example of the complex water-sealing sealants of the present invention. The present invention will be described in detail. Examples of the polyhydric alcohol represented as R (polyhydric alcohol residue) in the above-described general formula include aliphatic dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butylene glycol and neopentyl glycol; trihydric alcohols such as glycerol, trioxyisobutane, 1,2,3-butanetriol, 1,2,3-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-2,3,4-butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-pentanetriol, 2,3,4-hexanetriol, 4-propyl-3,4,5-heptanetriol, 2,4-dimethyl-2,3,4-pentanetriol, pentamethyl glycerol, pentaglycerol, 1,2,4-butanetriol, 1,2,4-pentanetriol and trimethylolpropane; tetrahydric alcohols such as erythritol, pentaerythritol, 1,2,3,4-pentanetetrol, 2,3,4,5-hexanetetrol, 1,2,3,5-pentanetetrol and 1,3,4,5-hexanetetrol; pentahydric alcohols such as adnite, arabitol and xylitol; and hexahydric alcohols such as sorbitol, mannitol and iditol. The polyether polyols represented by the above-described general formula may be obtained by adding alkylene oxide having 3 to 4 carbon atoms and ethylene oxide to these polyhydric alcohol in such a conventional manner as to give the desired molecular weight and to give the desired content of the ethylene oxide group. Either random or block addition of the alkylene oxide having 3 to 4 carbon atoms and the ethylene oxide may be employed therefor. The content of the oxyethylene group based on the molecular weight of polyether polyols ranges from 20 to 100% by weight. When the content of the oxyethylen group is less than 20%, the swelling ratio of the prepolymer having isocyanate groups obtained by reacting isocyanate becomes small, so that sufficient water-proof cannot be obtained. Example of the polyisocyanate include any polyisocyanates such as 1,4-butane diisocyanate, 1,6-hexane diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, 1,5-bis-isocyanato-1,3,5-trimethyl-cyclohexane, 1,3-bis-(isocyanatomethyl)-benzene and methylcyclohexane diisocyanate. Fatty acid triisocyanate may be employed together partially. Preferable Examples of aromatic polyisocyanate include any aromatic diisocyanates such as 2,4- or 2,6-tolylene diisocyanate or their isomer mixtures; 4,4'-diphenylmethane diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, m- or p-phenylene diisocyanate, 1,5-naphthylene diisocyanate and their isomers. Further, aromatic polyisocyanate having carbodiimide-, urethodione-, urethane-, urethoimine- or biuret group or isocyanurate circles may be employed alone or together. The prepolymer having isocyanate groups thus obtained can be used independently or simultaneously with an active hydrogen compound by kneading. The active hydrogen compound is polyol, polyamine or a mixture thereof each having 2 to 6 of active hydrogen atoms per one molecule and having an average molecular weight per active hydrogen atoms of 30 to 15,000, for example, low-molecular weight di or triols such as ethylene glycol, 1,4-butanediol, glycerol and trimethylol propane; polyalkylene glycols such as polypropylene glycol, ethylene oxide-propylene oxide copolymers; polymers of alkylene oxide such as ethylene oxide-propylene oxide and low-molecular weight triols such as glycerol, trymethylolpropane, 1,2-6-hexanetriol; low-molecular weight tetraols such as pentaerythritol or low-molecular weight hexaols such as solbitol; or polyamines such as ethylenediamine, 4,4'-methylenebis-1-chloroaniline or polymers of these polyamines and the above-described alkylene oxide. In the reaction of the prepolymer having isocyanate groups and the active hydrogen compound, any well-known catalyst for promoting the reaction of isocyanate group and an active hydrogen compound can be added. Examples of the catalyst to be added include triethylamine, triehtylenediamine, N-morpholine, stannous octate and dibutyl dilaurate. In connection with the ratio of the polyisocyanate and the active hydrogen compound in the above-described prepolymer having isocyanate groups, [NCO] / [H + ] is preferably 0.8 to 2.0, more preferably 1.1 to 1.7. Further, the above-described water-swelling urethane resin may further contain high molecular materials such as other urethane resins, epoxy resin and acryl resin, optionally, and additives of these resins such as calcium carbonate, clay, aluminium silicate, talc or titanium dioxide. An appropriate amount of a color former and an antioxidant can be also added thereto. Regarding the water-swelling resin (C) used in the complex water-sealing sealant of the present invention, it is preferable to blend and knead 10 to 97% by weight of the above-described non-water-swelling thermoplastic resin (A) and 3 to 90% by weight of the above-described water-swelling material (B) [ (A) + (B) = 100% by weight]. Examples of the above-mentioned vinyl chloride resin include homopolymer of vinyl chloride, copolymer of vinyl chloride and other monomers and graft polymer of vinyl chloride and other monomers, and chlorinated compounds of the homopolymer, the copolymer or the graft polymer. The vinyl chloride resin preferably has an average polymerization degree of 400 to 4000. An average polymerization degree is preferably 500 to 3000, more preferably 700 to 2000. When the average polymerization degree is less than 400, the strength of the water-swelling resin (C) lowers, and when it is more than 4000, the workability deteriorates. The vinyl chloride resin may be used in an amount of 10 to 97% by weight based on the mixture of the vinyl chloride resin and the water-swelling urethane resin, and it is preferably from 20 to 95% by weight, still preferably 30 to 90% by weight. When the amount of the vinyl chloride resin is less than 10% by weight, its workability etc. is lost, and the adjustment of hardness according to the plasticizer becomes difficult. Contrarily, when it exceeds 97% by weight, the water swellability deteriorates. The plasticizer is not particularly limited. Examples of such a plasticizer are those usually employed when preparing vinyl chloride resin, for example, phthalates such as dioctyl phthalate and ditridecyl phthalate; trimellitates such as trioctyl trimellitate; pyromellitates such as tetra 2-ethylhexyl pyromellitate; and adipate which is a condensate of adipic acid and diol such as 1,2-propylene glycol, triethylene glycol or neopentyl glycol. The above-mentioned water-swelling resin (C) may further contain additives generally added to the vinyl chloride resin. Examples of such additives include an organotin thermostabilizer such as dialkyltin mercaptide, dialkyltin malate and dialkyltin laurate; a metal soap such as calcium stearate, zinc stearate, cadmium stearate, barium stearate and lead stearate; an inorganic stabilizer such as lead tribasic sulfate, lead dibasic stearate, calcium hydroxide and calcium silicate; a chelating agent such as trisnonylphenylphosphite and alkylmonoallylphosphite; waxes such as ester wax and hydrocarbon wax; an epoxide compound such as soybean oil epoxide, linseed oil epoxide and bisphenolepoxide; and a filler such as calcium carbonate, talc, clay and mica. Pigment, antistatic agent, antioxidant, ultraviolet ray absorbing agent and the like may be also contained therein optionally. The extrusion molding used in the present invention will be explained. In order to mold the complex water-sealing sealant of the present invention by extrusion molding, a co-extruder is used. The co-extruder has two extruders each having the same or different aperture and each being combined to one die thereby extruding and molding the materials at a time. One example of the co-extruder suitable for molding the complex water-sealing sealant of the present invention by the extrusion molding is like this: a co-extruder having a 90 mm-aperture extruder and a 40 mm-aperture extruder combined to one die, wherein the non-water-swelling thermoplastic resin (A) is extruded by the 90 mm-aperture extruder, and the water-swelling resin (C) is extruded by the 40 mm-aperture extruder. The desired moldings may be obtained at a cylinder temperature of from 150 to 180°C, a die temperature of from 170 to 190°C and an extruder output of from 100 to 250 kg/hour for the 90 mm-aperture extruder, and at a cylinder temperature of from 160 to 190°C, a die temperature of from 170 to 190°C and an extruder output of from 5 to 50 kg/hour for the 40 mm aperture-extruder, but the molding condition is not limited to the above-mentioned conditions. Examples of the complex water-sealing sealant of the present invention include a complex water-sealing board used for the construction joint of concrete as shown in Fig. 1, a joint sealant used for the joint of concrete as shown in Fig. 2 and a sheet pile made of resin as shown in Fig. 3. In Figs. 1, 2 and 3, 1 shows the water-swelling part molded by the water-swelling resin (C) and 2 shows the non-water-swelling part molded by the non-water-swelling thermoplastic resin (A). 3 in Fig. 2 is the sponge part fixed after the molding in order to improve the waterstop of the joint sealant. In the complex water-sealing board and the joint sealant, the arrangement of the water-swelling part 1 is not limited to the arrangement shown in Figs. 1 and 2. The water-swelling part 1 may be freely and pertinently arranged in accordance with the object for using the complex water-swelling board and the joint sealant. In general in the sheet pile made of resin, the water-swelling part 1 is arranged in the cavity (joint part) of the sheet pile as shown in Fig. 3.

Claims: A complex water-sealing sealant comprising a non-water-swelling thermoplastic resin (A) being a polyvinyl chloride containing 100 to 200 parts by weight of a plasticizer based on 100 parts by weight of said polyvinyl chloride, and a water-swelling resin (C) obtained by kneating said non-water-swelling thermoplastic resin (A) and a water-swelling material (B) being a water-swelling urethane resin including prepolymer(s) having isocyanate groups, in which the content of terminal NCO groups amounts to 1 to 12%, obtained by the reaction of one or more polyether polyols represented by the following general formula and polyisocyanate; R[(OR 1 )n OH]p wherein R represents a polyhydric alcohol residue; (OR 1 )n represents a polyoxyalkylene chain comprising oxyalkylene groups each having an oxyethylene group and an alkylene group carrying three or four carbon atoms, provided that the content of the oxyethylene groups amounts to 20 to 100% of the total molecular weigh; n is a number corresponding to the degree of polymerization of the oxyalkylene groups and giving a hydroxyl group equivalent of 200 to 2500; and p is a number of 2 to 8, said complex water-sealing sealant being molded by the extrusion molding of said non-water swelling thermoplastic resin (A) and said water-swelling resin (C). The complex water-sealing sealant according to Claim 1, wherein said complex water-sealing sealant is a complex water-sealing board. The complex water-sealing sealant according to Claim 1, wherein said complex water-sealing sealant is a joint sealant. The complex water-sealing sealant according to Claim 1, wherein said complex water-sealing sealant is a sheet pile made of resin.

Inventors: HARA KOUZI, ICHIZUKA ISAMU, KOBE SHINJI, OHKUBO KEN, OKOUCHI YOSHITAKA, SAKURADA TADAYUKI, SHIMIZU HIROSHI, TAKAHASHI SHUITSU, WAKI HIROSHI, HARA, KOUZI, ICHIZUKA, ISAMU, KOBE, SHINJI, OHKUBO, KEN, OKOUCHI, YOSHITAKA, SAKURADA, TADAYUKI, SHIMIZU, HIROSHI, TAKAHASHI, SHUITSU, WAKI, HIROSHI, Hara, Kouzi, c/o Asahi Denka Kogyo K. K., ICHIZUKA, ISAMU, C/O ASAHI DENKA KOGYO K. K., Kobe, Shinji, c/o Asahi Denka Kogyo K. K., Ohkubo, Ken, c/o Riken Vinyl Ind. Co., Ltd., Okouchi, Yoshitaka, c/o Riken Vinyl Ind. Co., Ltd., Sakurada, Tadayuki, c/o Riken Vinyl Ind. Co., Ltd., Shimizu, Hiroshi, c/o Riken Vinyl Ind. Co., Ltd., Takahashi, Shuitsu, c/o Asahi Denka Kogyo K. K., Waki, Hiroshi, c/o Asahi Denka Kogyo K. K.
Applicants: ASAHI DENKA KOGYO KK, RIKEN VINYL IND, ASAHI DENKA KOGYO KABUSHIKI KAISHA, RIKEN VINYL INDUSTRY CO., LTD.
Application year: 1993
Main classification: C09K3
IPC codes: E02B3, C09K3, C08L101, B29K101, B29C47