Water-swellable water-stopping composition

Abstract

Provided is a water-swellable composition that is excellent in water-swellability, shape retention after water expansion, non-adhesiveness, and deformability. [Solution] According to the present invention, there is provided a water-swellable water-stopping composition containing 10 to 300 parts by mass of an inorganic compound and 10 to 300 parts by mass of a softener relative to 100 parts by weight of rubber A, which is an epichlorohydrin-based rubber copolymerized with an ethylene oxide component.

Description

[Technical field]

[0001] The present invention relates to a water-swellable water-stopping composition capable of producing a sealing material. [Background technology]

[0002] In the fields of civil engineering and construction, water-expanding water-stopping materials formed into tapes or films are used at the connections of various pipes, such as tunnel segments, underground Hume pipes, and U-shaped gutters for water supply and sewerage, to prevent water leakage and stop water leakage.

[0003] For example, Patent Document 1 discloses a vulcanization composition containing a rubber component consisting of an epichlorohydrin polymer rubber and a styrene-butadiene rubber (SBR), magnesium oxide, a sulfenamide compound, sulfur and / or an active sulfur-releasing organic vulcanization accelerator, a thiourea compound, and, if necessary, a water-absorbing substance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2006-028337 Summary of the Invention [Problem to be solved by the invention]

[0005] A sealant manufactured using a water-swellable water-stopping composition exhibits water-stopping properties by absorbing water and expanding in volume when it comes into contact with water. Such a sealant is required to simultaneously have two contradictory properties: excellent expansion property due to water absorption and excellent shape retention stability that does not collapse even when it absorbs water and expands.

[0006] In addition, since the water-swellable composition of Patent Document 1 is in the form of a tape or sheet, if the shape of the area to be waterproofed is complex, it is difficult to freely deform and apply the water-swellable composition to fit the shape.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a water-swellable composition that is excellent in water-swellability, shape retention after water expansion, non-adhesiveness, and deformability. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by using a composition with a specific blend ratio, which has led to the completion of the present invention.

[0009] That is, the present invention is as follows. [1] A water-swellable water-stopping composition comprising 10 to 300 parts by mass of an inorganic compound and 10 to 300 parts by mass of a softener, based on 100 parts by weight of rubber A, which is an epichlorohydrin rubber copolymerized with an ethylene oxide component. [2] The water-swellable water-stopping composition according to [1], further comprising 300 parts by mass or less of a water-absorbent resin other than the rubber A per 100 parts by weight of the rubber A. [3] The water-swellable water-stopping composition according to [1] or [2], wherein the inorganic compound comprises silica. [4] The water-swellable water-stopping composition according to [1] or [2], wherein the softener contains at least one of an ester-based plasticizer or an ether-based plasticizer. [5] The water-swellable water-stopping composition according to any one of [1] to [4], which is used as a sealing material. Effect of the Invention

[0010] According to the present invention, it is possible to provide a water-swellable water-stopping composition capable of producing a sealing material having excellent water-swellability, shape retention after water-swelling, non-adhesiveness, and deformability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Below, we will explain in detail the form for implementing the present invention (hereinafter referred to as the "present embodiment"). However, the present invention is not limited to this, and various modifications are possible without departing from the gist of the present invention.

[0012] 1. Water-swellable water-stopping composition The water-swellable water-stopping composition of this embodiment contains 10 to 300 parts by mass of an inorganic compound and 10 to 300 parts by mass of a softener, based on 100 parts by weight of rubber A (hereinafter also referred to as "rubber A"), which is an epichlorohydrin rubber copolymerized with an ethylene oxide component. Such a water-swellable composition is a composition with excellent deformability, and can be used as a putty that can be easily used according to the shape. That is, the composition can be provided as a putty-like water-swellable composition.

[0013] <Epichlorohydrin rubber copolymerized with ethylene oxide component> Examples of the epichlorohydrin-based rubber A in which an ethylene oxide component is copolymerized include epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer, etc. These rubbers A may be used alone or in combination of two or more.

[0014] Rubber A contains, for example, 70 to 95 mol %, and preferably 80 to 90 mol %, of an ethylene oxide component. With the ethylene oxide component in this range, water swellability is improved. Rubber A may contain, for example, 5 to 30 mol %, and preferably 10 to 20 mol %, of an epichlorohydrin component, and 0 to 10 mol %, and preferably 0 to 8 mol %, and more preferably 0 to 6 mol %, of an allyl glycidyl ether component.

[0015] The water-swellable water-stopping composition preferably contains 15 to 55 mass% of rubber A relative to 100 mass% of the water-swellable water-stopping composition. The content of rubber A is specifically, for example, 15, 18, 20, 25, 30, 35, 40, 45, 50, 53, or 55 mass%, and may be within a range between any two of the numerical values ​​exemplified here.

[0016] <Water absorbent resin> The water-absorbing resin is also called SAP (Super Absorbent Polymer), and is a polymer having a water-absorbing ability to absorb 300 to 2000 times its own weight in water and a water-retaining ability to hold the water in a very stable state. The water-absorbing resin is not particularly limited, but examples thereof include acrylic polymers such as partial sodium salt of acrylic acid polymer or its crosslinked product, partial sodium salt of acrylic acid graft polymer or its crosslinked product, starch-acrylic acid graft polymer salt or its crosslinked product, saponification product of vinyl acetate-acrylic acid ester copolymer or its crosslinked product, 2-acrylamido-2-methylpropanesulfonic acid-acrylic acid copolymer salt or its crosslinked product; cellulose compounds such as sodium carboxymethylcellulose and ammonium carboxymethylcellulose; alkylene oxide polymers such as polyalkylene oxide and modified polyalkylene oxide; hydrolyzate of starch-acrylonitrile graft polymer, hydrolyzate of acrylonitrile copolymer or acrylamide copolymer or their crosslinked products, crosslinked product of cationic monomer, crosslinked isobutylene-maleic acid copolymer, etc. The water-absorbing resin may be used alone or in combination of two or more kinds. In this specification, the "water-absorbing resin" refers to a water-absorbing resin other than rubber A, and does not include rubber A.

[0017] Among these, the water-absorbent resin preferably contains an alkylene oxide polymer, and may be an alkylene oxide polymer. By using such a water-absorbent resin, water swelling property tends to be further improved.

[0018] The content of the water-absorbing resin is, for example, 0 to 300 parts by mass, preferably 1 to 200 parts by mass, and more preferably 5 to 50 parts by mass, relative to 100 parts by mass of rubber A. The water-swellable water-stopping composition may contain 300 parts by mass or less of a water-absorbing resin other than rubber A relative to 100 parts by mass of rubber A. The content of the water-absorbing resin is, for example, 0, 1, 5, 10, 20, 30, 40, 50, 55, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 300 parts by mass relative to 100 parts by mass of rubber A, and may be within a range between any two of the numerical values ​​exemplified here.

[0019] <Inorganic compounds> The inorganic compound preferably contains silica, and more preferably is silica. Silica is a general term for silicon dioxide or a substance composed of silicon dioxide, and is also called silicic acid anhydride, silicic acid, and silicon oxide in addition to silica. Silica takes various forms (crystalline polymorphs) depending on conditions such as pressure and temperature, and is broadly divided into two types: crystalline silica and non-crystalline silica.

[0020] The water-swellable water-stopping composition contains 10 parts by mass or more of silica per 100 parts by mass of rubber A, and thereby the water-swellability becomes particularly good.

[0021] The inorganic compound may include inorganic compounds other than silica. Examples of such inorganic compounds include metal oxides such as calcium carbonate, alumina, aluminosilicate, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, aluminum hydroxide, and ferrites; hydrated inorganic substances such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and hydrotalcite; metal carbonates (excluding calcium carbonate) such as basic magnesium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, and barium carbonate; calcium salts such as calcium sulfate and calcium silicate; diatomaceous earth, dolomite, and the like. Examples of suitable fillers include butadiene, barium sulfate, mica, activated clay, imogolite, glass beads, silica-based baluns, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon baluns, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, zinc borate, various magnetic powders, fly ash, inorganic hollow fillers, perlite, obsidian, perlite, rosin, diatomaceous earth, dehydrated sludge, boron, glass fibers, sodium tetraborate hydrate (borax), and clay minerals.

[0022] The content of the inorganic compound is 10 to 300 parts by mass, preferably 50 to 230 parts by mass, and more preferably 70 to 210 parts by mass, relative to 100 parts by mass of rubber A. If the content of the inorganic compound is less than 10 parts by mass, the non-adhesiveness is deteriorated. On the other hand, if the content of the inorganic compound is more than 300 parts by mass, the deformability is deteriorated. The content of the inorganic compound is specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 parts by mass relative to 100 parts by mass of rubber A, and may be within the range between any two of the numerical values ​​exemplified here.

[0023] <Softener> The softener is not particularly limited, but examples thereof include rapeseed oil, cottonseed oil, palm oil, coconut oil, peanut oil, tall oil, pine tar, mineral oil, process oil (paraffinic oil, naphthenic oil, and aromatic process oil), ester plasticizer, ether plasticizer, ether ester plasticizer, etc. The softener may be used alone or in combination of two or more. Among these, it is preferable to include at least one of an ester plasticizer or an ether plasticizer.

[0024] Examples of the ester-based plasticizer include phthalates such as di(2-ethylhexyl)phthalate (DEHP) and dibutylphthalate (DBP); aliphatic dibasic acid esters such as di(2-ethylhexyl)adipate (DEHA) and di(2-ethylhexyl)sebacate (DEHS); trimellitic acid esters such as tri(2-ethylhexyl)trimellitic acid ester (TEHTM) and triisononyltrimellitic acid ester (TINTM); phosphate esters such as triisopropylphenylphosphate; adipic acid polyesters such as adipic acid polyester; and others such as maleic acid esters, fumaric acid esters, citrate esters, oleic acid esters, ricinoleic acid esters, stearic acid esters, and glycolic acid esters.

[0025] Examples of the ether-based plasticizer include bis[2-(2-butoxyethoxy)ethyl]adipate (DBEEA), polyethylene glycol ester, and the like.

[0026] The content of the softener is 10 to 300 parts by mass, preferably 50 to 250 parts by mass, and more preferably 100 to 200 parts by mass, relative to 100 parts by mass of rubber A. If the content of the softener is less than 10 parts by weight, the deformability is poor. On the other hand, if the content of the softener is more than 200 parts by weight, the non-adhesiveness and shape stability are poor. The content of the softener is specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 parts by mass relative to 100 parts by mass of rubber A, and may be within the range between any two of the numerical values ​​exemplified here.

[0027] <Other additives> In addition to the above components, the water-expandable composition of this embodiment may also contain, as necessary, rubbers or thermoplastic elastomers other than Rubber A, and various additives used in rubbers or thermoplastic elastomers, such as crosslinking (vulcanization) agents, crosslinking (vulcanization) aids, antioxidants, UV inhibitors, tackifier resins, lubricants, dispersants, and fibrous compounds.

[0028] <Crosslinking agents and crosslinking accelerators> In the case where the water-swellable water-stopping composition of the present embodiment does not require crosslinking (vulcanization) treatment, it is preferable that the composition does not substantially contain a crosslinking agent (vulcanizing agent) and / or a crosslinking accelerator (vulcanization accelerator). In the case where the composition requires crosslinking treatment, the composition may contain a crosslinking agent and / or a crosslinking accelerator.

[0029] Here, the crosslinking agent is not particularly limited as long as it is a crosslinking agent capable of crosslinking rubber, and examples thereof include sulfur-based compounds such as sulfur and polysulfides, oxime compounds such as p-quinone dioxime and p,p'-dibenzoylquinone oxime, and organic peroxide compounds such as t-butyl hydroperoxide, acetylacetone peroxide, and cumene hydroperoxide. Note that crosslinking agents, particularly sulfur-based compounds such as sulfur and polysulfides, can also be considered to act as crosslinking accelerators.

[0030] The crosslinking accelerator is not particularly limited as long as it is a crosslinking accelerator used for the purpose of promoting the crosslinking of rubber. Examples of the crosslinking accelerator include thiuram compounds such as tetramethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, and dipentamethylenethiuram tetrasulfide; thiazole compounds such as 2-mercaptobenzothiazole and dibenzothiazole disulfide; carbamate compounds such as zinc dimethyldithiocarbamate and zinc dibutyldithiocarbamate; aldehyde amine compounds such as n-butylaldehyde aniline; sulfenamide compounds such as N-cyclohexyl-2-benzothiazylsulfenamide; guanidine compounds such as diorthotolylguanidine and diorthonitrileguanidine; thiourea compounds such as thiocarbanilide, diethylthiourea, trimethylthiourea, and ethylenethiourea; and zinc oxide. In addition, the crosslinking accelerator, particularly the thiourea-based compound, can be considered to act as a crosslinking agent.

[0031] In the case of an embodiment that does not require crosslinking treatment, "substantially does not contain" a crosslinking agent or the like means that the crosslinking agent and crosslinking accelerator are each at least less than 0.1 parts by mass, more preferably less than 0.01 parts by mass, and even more preferably less than 0.005 parts by mass, relative to 100 parts by mass of rubber A. The lower limit of the content of the crosslinking agent and crosslinking accelerator is not particularly limited, but can be below the detection limit. In one embodiment, the total content of the crosslinking agent and crosslinking accelerator is preferably less than 0.11 parts by mass, relative to 100 parts by mass of rubber A.

[0032] The content of the rubber or thermoplastic elastomer other than Rubber A is, for example, 0 to 40 parts by mass, and preferably 0 to 10 parts by mass, relative to 100 parts by mass of Rubber A. Examples of the rubber other than Rubber A include styrene butadiene rubber (SBR).

[0033] <Production method and uses of water-expandable composition> The water-expandable composition of the present embodiment can be produced by kneading the necessary components. A molded article using the water-expandable composition can be produced by molding the water-expandable composition by pressing or the like. This molded article can be used as a sealing material.

[0034] The apparatus for kneading the compound includes a conventional kneading apparatus such as a mixer, a Banbury mixer, a kneader mixer, a two-roll mill, etc. The apparatus for molding the kneaded compound includes a conventional molding apparatus such as a press molding apparatus, an extrusion molding apparatus, a calendar molding apparatus, etc. The shape of the molded product may be a sheet or a tape, etc., and may be designed appropriately according to the application.

[0035] Furthermore, the water-swellable water-stopping composition of the present embodiment can have appropriate deformability as a putty, and may be used as a putty-like sealing material. EXAMPLES

[0036] The present invention will now be described in more detail with reference to the following examples, in which the unit of the amount of each substance used is parts by mass.

[0037] 1. Preparation of Water-Swellable Water-Stopping Composition The components shown in Table 1 were kneaded for 10 minutes at 100° C. using a 3L pressure kneader (manufactured by Moriyama Co., Ltd., model: DS3-10MWB-S) to obtain water-swellable compositions of the Examples and Comparative Examples. The amount of each substance used in Table 1 is in parts by mass unless otherwise specified.

[0038] [Table 1]

[0039] [Table 2]

[0040] [Table 3]

[0041] Details of each component in Table 1 are as follows. <Epichlorohydrin rubber> Rubber a-1: Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer: "Epion 301" manufactured by Osaka Soda Co., Ltd. Rubber a-2: Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer: "Epichromer DG" manufactured by Osaka Soda Co., Ltd. Rubber a-3: Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer: Osaka Soda Co., Ltd., "Epichromer CG102" Rubber b-1: Epichlorohydrin polymer: "Epichromer H" manufactured by Osaka Soda Co., Ltd. <Water absorbent resin> Modified polyalkylene oxide: "Aquacoke TWB" manufactured by Sumitomo Seika Chemicals Co., Ltd. Acrylic acid polymer partially cross-linked with sodium salt: "AQUALIC CS-6S" manufactured by Nippon Shokubai Co., Ltd. <Inorganic compounds> Silica: Tosoh Silica Corporation, "Nipsil VN3" Calcium carbonate: "TA-044" manufactured by Chichibu Lime Industry Co., Ltd. <Softener> Polyether ester plasticizer: Adeka Cizer RS-700, manufactured by ADEKA Corporation. Process oil: "Diana Process Oil NP-24" manufactured by Idemitsu Kosan Co., Ltd.

[0042] 2. Evaluation The water-swellable waterproof compositions obtained in the Examples and Comparative Examples were subjected to various measurements and evaluations as shown below.

[0043] <Deformability (softness)> The water-swellable composition was processed into a sheet-like molded body having a thickness of 2 mm using a press (temperature: 80°C, time: 1 minute), and the obtained molded body (specimen 1) was used to measure the softness of the specimen 1 at a load of 150 g and a temperature of 21°C in accordance with JIS A5752. A prescribed cone was penetrated vertically into the specimen 1, and the penetration depth was measured to the nearest 0.1 mm. Based on the penetration depth, the deformability was evaluated according to the following criteria. ◎: 60 [1 / 10 mm] or more ○: 50 [1 / 10 mm] or more and less than 60 [1 / 10 mm] △: 40[1 / 10mm] or more and less than 50[1 / 10mm] ×: Less than 40 [1 / 10 mm]

[0044] <Non-adhesive> A latex glove was put on, and 100 g of water-swellable composition was gripped 10 times. The mass of the substance attached to the glove was measured, and the amount of the substance attached was calculated based on the following formula. Based on the amount of the substance attached, the non-adhesiveness was evaluated according to the following criteria. The lower the non-adhesiveness, the easier the processing. Amount of attached substance (g) = (mass of glove after squeezing 100 g of water-swellable composition 10 times) - (original mass of glove) ◎: Less than 0.02[g] ○: 0.02[g] or more and less than 0.05[g] △: 0.05g or more and less than 0.10g ×: 0.10[g] or more

[0045] <Water swelling> According to JIS K-6258, 10 g of the water-swellable composition was molded into a spherical molded body (specimen 2), which was immersed in water at 23° C. for 7 days, and the volume change rate before and after immersion was calculated using the following formula. The volume change rate before and after immersion indicates the amount of water supplied to specimen 2, i.e., the amount of volume change, and the water-swellability was evaluated according to the following evaluation criteria. Volume change rate (%) = ((cd)-(ab)) / (ab) x 100 a: Mass in air before immersion in water, b: Mass in water before immersion c: Mass in air after immersion in water, d: Mass in water after immersion (Evaluation Criteria) ◎: Volume change rate is 150% or more ○: Volume change rate is 130% or more and less than 150% △: Volume change rate is 110% or more but less than 130% ×: Volume change rate is less than 110%

[0046] <Shape retention after expansion with water> 5 g of the water-swellable composition was molded into a spherical molded body (specimen 3), and after immersion in water at 23° C. for 7 days, the shape retention of the specimen was visually observed and evaluated according to the following criteria. (Evaluation Criteria) ◎: No cracks were observed in specimen 3 after expansion with water. ○: Cracks were observed in test piece 3 after it expanded with water, but it did not collapse even when it was taken out of the water. △: Cracks were observed in test piece 3 after it expanded with water, and it collapsed when it was removed from the water. ×: Test specimen 3 collapses in water after swelling with water

Claims

1. The rubber A is an epichlorohydrin-based rubber copolymerized with an ethylene oxide component, and the rubber A contains 50 to 230 parts by mass of an inorganic compound and 50 to 250 parts by mass of a softener, The rubber composition further contains 300 parts by mass or less of a water-absorbing resin other than the rubber A relative to 100 parts by weight of the rubber A, The rubber A contains 70 to 95 mol% of an ethylene oxide component, The content of the rubber or thermoplastic elastomer other than the rubber A is 0 to 40 parts by mass per 100 parts by mass of the rubber A.

2. The water-swellable water-stopping composition according to claim 1, wherein the rubber A is contained in an amount of 15 to 55% by mass relative to 100% by mass of the water-swellable water-stopping composition.

3. The water-swellable water-stopping composition according to claim 1 or 2, wherein the inorganic compound comprises silica.

4. The water-swellable water-stopping composition according to claim 1 or 2, wherein the softener comprises at least one of an ester-based plasticizer and an ether-based plasticizer.

5. The water-swellable water-stopping composition according to claim 1 or 2, which is used as a sealing material.

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