JPH0413145B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a sealing material for sealing between various structures. More specifically, the present invention relates to a water-swellable waterproof material for use between structures that absorbs water and expands, thereby completely preventing water from seeping out from the outside or inside. Prior Art Rubber compositions in which synthetic rubber is blended with water-absorbing substances such as polyvinyl alcohol, polyacrylates, carboxymethyl cellulose, and hydroxyethyl cellulose are disclosed in, for example, Japanese Patent Application Laid-open Nos. 143653-1982 and 54-1983.
They are known from Japanese Patent No. 7461, No. 54-7463, and No. 54-20066, and because they absorb water and expand, they are useful as water leakage prevention agents, that is, water-stopping materials. However, such compositions have the disadvantage that because the water-absorbing substances they contain are water-soluble, they cannot swell to a high degree with water and are difficult to generate high swelling pressure, which is important for water-stopping effects. In addition, the water absorption rate is slow and the water stopping effect cannot be exerted early. Further, rubber compositions using swelling urethane as a water-absorbing substance are known, but since the hydrophilicity of the urethane is not necessarily sufficient, only a relatively low swelling pressure can be obtained, and the water absorption rate is also extremely slow. Furthermore, compositions in which a super absorbent resin made of a copolymer of α-olefin and maleic anhydride is used as a water-insoluble super absorbent resin, and this is combined with a nitrile paint, natural rubber, etc. are also available, for example. Unexamined Japanese Patent Publication 1973
It is known from Japanese Patent No. 94525 and No. 54-110262, and such compositions are useful as swelling paints or caulking materials. However, it is difficult to obtain high swelling pressures with such compositions. In other words, rubbers that are amorphous at room temperature, such as nitrile rubber and natural rubber, cold-flow due to external force in an unvulcanized state, so even if the super absorbent resin in which they are blended absorbs water and expands, Due to the cold flow of the rubber, swelling pressure cannot be applied to areas that require water stoppage, and a sufficient water stoppage effect cannot be obtained. One way to overcome this drawback is to vulcanize rubber, but in that case, the network of crosslinked rubber molecules prevents the superabsorbent resin from sufficiently expanding due to water absorption, making it difficult to maintain the required swelling pressure. difficult to obtain. As a result of various studies to improve the above-mentioned drawbacks, the present inventors have discovered a 1,3-diene rubber containing 5 to 50% crystalline or glassy region at room temperature and a specific highly water-absorbent rubber in the rubber. It has been discovered that a sheet-like or string-like water-stopping material molded from a rubber composition in which a rubber resin is dispersed is effective as a water-stopping material between structures. When the waterproofing material is applied, it not only swells in the direction of the thickness of the surface to which it is applied, but also swells and stretches in the direction of the surface to which it is applied other than the thickness, causing it to come off from between the structures and exhibit sufficient waterstopping effects. This method had the disadvantage that there were many cases where it was not possible. The purpose of the present invention is to improve the drawbacks of the above-mentioned water-stopping materials, and to provide a water-swellable water-stopping material for use between structures that has a rapid and sufficient water-stopping effect and has excellent workability. It is something to do. According to the present invention, the above purpose is achieved by 5-50% at room temperature.
1,3- containing crystalline or glassy regions of
α, β having one or two groups in the molecule selected from carboxyl groups and groups derivable into carboxyl groups in the diene rubber
- Consisting of a crosslinked product containing 40 mol% or more of unsaturated compounds as a monomer component, its own weight relative to distilled water.
A water-swellable rubber layer containing a vulcanizing agent, in which a powdered superabsorbent resin with a water absorption capacity of 20 to 500 times the weight is dispersed (A)
and a vulcanizing agent-containing water-inswellable rubber layer (B) that absorbs expansion in directions other than the thickness direction due to water absorption of the rubber layer (A) and simultaneously vulcanize the resulting composite. This is achieved by using it as a water material. In particular, when the composite is molded together so that the ratio (A/B) of each layer is 15/85 to 85/15, or when the water-swellable rubber layer (A)
is a crosslinked product of a polymer containing as a main component an α,β-unsaturated compound having a carboxyl group in a 1,3-diene rubber containing 5 to 50% crystalline or glassy regions at room temperature. A powdered superabsorbent resin with a water absorption capacity of 20 to 500 times its own weight in distilled water is dispersed, and a vulcanizing agent is mixed therein, and the water-inswellable rubber layer (B) weighs 20 to 200 kg. The above object is easily achieved when the composition is made of a co-vulcanized rubber composition having a stress at 300% elongation of /cm ² . The value obtained by dividing the weight of distilled water absorbed by the superabsorbent resin by the weight of the resin before absorption is hereinafter referred to as "water absorption capacity". The water-swellable rubber layer (A) used in the present invention is made of a composition in which a superabsorbent resin is dispersed in rubber. This rubber is an elastic polymer containing 1,3-diene compounds such as butadiene, isoprene, dimethylbutadiene, and chloroprene as repeating units, such as natural rubber (NR), synthetic cis-1,
4-Polyisoprene rubber (IR). Polybutadiene rubber (BR), styrene-diene random copolymer rubber (SBR or SIR), acrylonitrile-diene copolymer rubber (NBR or NIR), chloroprene rubber (CR), isobutylene-isoprene copolymer rubber (IIR), ethylene-propylene - Diene copolymer rubber (EPDM), trans-1,4-polyisoprene rubber, styrene-diene block copolymer rubber, etc., but especially 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene) ,2,3
-dimethyl-1,3-butadiene, 2-chloro-
Those containing 1,3-diene such as 1,3-butadiene as a recycle unit are preferred. The rubber used in the present invention must further contain 5 to 50% crystalline or glassy regions at room temperature. Such materials include crystalline polymers made of 1,3-diene and 1,3-diene.
A block copolymer of a non-crystalline 3-diene polymer and a glassy polymer can be mentioned. Examples of the crystalline polymers include chloroprene rubber, gutta-percha, balata, synthetic trans-
Mention may be made of crystalline rubbers composed of substantially single-component repeating units, such as 1,4-polyisoprene. Among them, chloroprene rubber is preferred from the viewpoint of swelling properties of the water-swellable rubber (A). These crystalline polymers have a molecular weight of 50,000 to 1,000,000 and a melting point of the crystalline portion.
A temperature of 20 to 90°C is preferred. Further, as the block copolymer rubber, 1,
An example is a block copolymer of 3-diene and a monovinyl-substituted aromatic compound such as styrene, α-methylstyrene, or vinyltoluene, which forms a glassy polymer at room temperature. There are various types of
A-B-A type block copolymer rubber (where A is a monovinyl-substituted aromatic compound, preferably has a glass transition point of 20 to 90°C and a degree of polymerization of 10 to 2500)
means a glassy polymer block with B
is composed of 1,3-diene, and preferably has a degree of polymerization of
500 to 15,000. ) is preferably used. Hydrogenated products of the block copolymer rubber can also be used in the same manner. These preferably used rubbers have a crystalline region or a glassy region at room temperature, but if the amount exceeds 50%, the rubber becomes hard and the superabsorbent resin powder particles absorb water and expand. Therefore, it is impossible to provide a water-swellable rubber layer exhibiting high water absorption rate and high swelling pressure, making it difficult to achieve the intended purpose. Furthermore, if there is no crystalline or glassy region, or if it is present, it is less than 5%, the tendency to cold flow in the unvulcanized state becomes large and a desirable water-swellable rubber layer is often not obtained. It is therefore necessary that the crystalline or glassy region be between 5 and 50%, preferably between 5 and 35%. Note that the term "crystalline region" as used herein has the usual meaning in the field and is expressed by the degree of crystallinity, and the method for measuring it is also well known. (For example, “Polymer Papers” No. 31
Vol., pp. 138-139). In addition, the glassy region is
It has the ordinary meaning in the art and is adjusted by the amount of monomer forming the glassy polymer. Among these rubbers, chloroprene rubber having a crystalline area of 5 to 50% at room temperature is most preferred. In addition, if the water absorption capacity of the superabsorbent resin dispersed in these rubbers is small, the swelling capacity of the water-swellable rubber layer will be small, while if the water absorption capacity is too high, the strength of the superabsorbent resin swollen with water will decrease. becomes too low, and a water-swellable rubber layer exhibiting sufficient swelling pressure cannot be obtained in either case. Therefore, a water-stopping material formed by laminating such water-swellable rubber layers has insufficient water-stopping effect. From this point of view, the water absorption capacity of the super absorbent resin needs to be 20 to 500 times, and particularly preferably 50 to 400 times. From the viewpoint of water absorption and durability of the water-swellable rubber layer, such super absorbent resins include those derived from carboxyl groups and carboxyl groups such as carboxylic acid salts, carboxylic acid amides, carboxylic acid imides, and carboxylic acid anhydrides. α,β- having one or two groups in the molecule selected from among the groups that can
It is necessary that the crosslinked product contains an unsaturated compound as a monomer component. The α,β-unsaturated compounds include, for example, acrylic acid, methacrylic acid, acrylamide, methacrylic acid amide, maleic anhydride, maleic acid, maleic acid amide, maleic acid imide, itaconic acid, crotonic acid, fumaric acid, mesacon. It may be an acid, etc., and may be used in combination with other copolymerizable monomer components within a range that satisfies the performance required of the superabsorbent resin. The other copolymerizable monomers include ethylene, propylene, isobutylene, 1-
Examples include α-olefins such as butylene, diisobutylene, methyl vinyl ether, styrene, vinyl acetate, acrylic esters, methacrylic esters, and acrylonitrile, vinyl compounds, and vinylidene compounds. When combined with other monomers, the α,β-unsaturated compound containing a carboxyl group or a group convertible thereto must account for 40 mol% or more of the total monomer components. In order to obtain a crosslinked product containing as a monomer an α,β-unsaturated compound having a carboxyl group or a group convertible thereto, a polymer is preferably first prepared by a conventional method using a radical polymerization catalyst. do.
The degree of polymerization is not particularly limited, but is 10~
3000 is preferred. Among the polymers prepared in this way, polymers such as acrylic acid and methacrylic acid, α
- Copolymers of olefins or vinyl compounds and maleic anhydride are preferred. These polymers or copolymers can be reacted with compounds such as hydroxides, oxides or carbonates of alkali metals or alkaline earth metals such as sodium, potassium, magnesium, calcium, barium, ammonia, amines, etc. It is preferable to make it more hydrophilic. In this reaction, the polymer is dissolved in a solvent, preferably water, and the alkali metal compound,
This is carried out by adding alkaline earth metal compounds, ammonia, amines, etc. with stirring. In this reaction, sodium hydroxide, potassium hydroxide, and ammonium are preferably used from the viewpoint of reactivity and durability of the superabsorbent resin obtained. The thus obtained polymer containing an α,β-unsaturated compound as a monomer component is subjected to a crosslinking reaction, and the crosslinking agents used include polyvalent epoxy compounds, polyvalent amines, polyhydric alcohol,
Examples include amino alcohol, polyisocyanate, and polyhydric halohydrin, with polyepoxy compounds and polyvalent amines being particularly preferred. Examples of polyvalent epoxy compounds include glycerin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, and the like. Polyvalent amines include, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine,
Examples include polyethyleneimine with a molecular weight of 5000 or less. The crosslinking reaction is carried out by adding the crosslinking agent to a polymer containing the α,β-unsaturated compound as a monomer component. At this time, heating may be performed or a solvent may be used. When using a polyvalent epoxy compound or a polyvalent amine as a crosslinking agent, it is preferable to conduct the crosslinking under heating and in the presence of water. In such cases, drying or heat treatment is preferred. The degree of crosslinking is adjusted by appropriately selecting the amount of crosslinking agent used so that a superabsorbent resin exhibiting the desired water absorption capacity described above can be obtained. Preferred examples of the super absorbent resin in the present invention are listed below. (1) Maleic acid or maleic anhydride, maleic acid derivatives such as maleic acid amide and maleic acid imide, and ethylene, propylene, butylene, isobutylene, diisobutylene, etc. with 2 or more carbon atoms.
12, preferably 2 to 8 linear or branched α
-Crosslinked product of copolymer with olefin and reactant with alkali metal compound, alkaline earth metal compound, ammonia, amine, etc. (2) Maleic acid or its derivative and styrene, vinyl acetate, methyl vinyl ether, acrylic acid Crosslinked products of reaction products of copolymers with vinyl or vinylidene compounds such as esters, methacrylic esters, acrylonitrile, and alkali metal compounds, alkaline earth metal compounds, ammonia, amines, etc. (3) Acrylic acid or methacrylic acid (4) A copolymer of acrylic acid or methacrylic acid and the vinyl or vinylidene compound of (2) above. Crosslinked products of reactants with alkali metal compounds, alkaline earth metal compounds, ammonia, amines, etc. Among these, in terms of water absorption and durability,
A crosslinked product of the reaction product of isobutylene-maleic anhydride copolymer and sodium hydroxide, potassium hydroxide or ammonia, and a crosslinked product of the reaction product of polyacrylic acid and sodium hydroxide (i.e., sodium polyacrylate) are Particularly preferred. The superabsorbent resin thus obtained is desirably used by pulverization into particles that can pass through a 20-mesh sieve. If the particle size is too large, the water-swellable rubber layer often expands unevenly and loses its surface smoothness. Note that the mesh flow referred to here is defined by JIS-ZSS01. The molded product of the water-swellable rubber layer (A) is prepared by mixing 100 parts by weight of rubber, 5 to 500 parts by weight of powdered superabsorbent resin, and a small amount of vulcanizing agent using a mixer such as a roll mixer, Banbury mixer, or kneader. By kneading in a conventional manner, a mixture in which the superabsorbent resin is dispersed in the rubber and a vulcanizing agent is mixed is obtained, and then the mixture is shaped into a sheet, plate, or other desired shape. Produced by molding. In addition to the vulcanizing agent, other rubber vulcanization products such as vulcanization accelerators, vulcanization aids, and activators may be blended. The mixture may contain rubber reinforcing agents, fillers, rubber softeners, plasticizers, tackifiers, processing aids, anti-aging agents, antioxidants, ozone anti-aging agents, ultraviolet absorbers, colorants, etc. There is no problem. In addition, the water-insoluble gum layer (B) supports the water-swellable rubber layer (A) that is laminated on the rubber layer to form a surface layer, and when used as a water-stopping material, the thickness elongation due to water absorption and swelling in a direction other than that, i.e., the width direction of the applied surface (here, in water-stopping materials, the lamination direction of the laminate is referred to as the thickness direction, but this refers to the length direction and width direction). This layer has the effect of regulating the Rubbers used for this water-inswellable rubber layer (B) include, for example, natural rubber (NR),
Synthetic cis-1,4-polyisoprene rubber (IR),
Polybutane diene rubber (BR), styrene-diene (random or block) copolymer rubber (SBR)
or SIR, etc.), acrylonitrile-diene copolymer rubber (NBR or NIR), butyl rubber, chloroprene rubber (CR), isobutylene-isoprene copolymer rubber (IIR), ethylene-propylene-diene copolymer rubber (EPDM), urethane rubber, etc. can be mentioned. The water-inswellable rubber layer (B) is made by blending a small amount of vulcanizing agent with the above rubber, and if necessary, in addition to the vulcanizing agent, other vulcanization accelerators, vulcanization aids, activators, etc. Rubber vulcanized products may also be incorporated. Moreover, there is no problem even if various rubber compounding chemicals as mentioned above are blended as necessary. If the stress at the time of 300% elongation of the rubber molded material forming this water-inswellable rubber layer (B) is too small, the elongation due to swelling in the length and width directions of the water stop material cannot be regulated. On the other hand, if the stress is too large, the water stop material becomes too hard. Therefore, the stress at 300% elongation of the rubber molded product forming the water-inswellable rubber layer is
It is necessary to use 20 to 200 Kg/cm ² , preferably 30 to 150 Kg/cm ² . In the present invention, the water-swellable water stop material is made of a composite formed by laminating and simultaneously vulcanizing a water-swellable rubber layer (A) and a water-insoluble rubber layer (B). When the composite comes into contact with water, it rapidly absorbs water and generates swelling pressure, and has a water-swellable rubber layer that exhibits a water-stopping effect.
This is a laminate that is stacked so that (A) is exposed on the surface. The water-stopping material of the present invention is similar to a water-stopping material with a three-layer structure consisting of a composite formed by laminating water-swellable rubber layers (A) on both sides of a water-insoluble rubber layer (B) and simultaneously vulcanizing them. It is preferable because it has water absorption and swelling and water stop properties, and requires less material compared to other materials. The laminated form is preferably a two-layer laminate formed by integrally molding a water-swellable rubber layer (A) and a water-insoluble rubber layer (B). In the composite, if the proportion of the water-swellable rubber layer (A) is small, sufficient swelling pressure to stop water cannot be generated, and conversely, the proportion of the water-insoluble rubber layer (B) is small. In this case, it is not possible to sufficiently absorb the elongation due to swelling of the water stop material in the length direction and width direction. The above-mentioned composite is prepared by adding a vulcanizing agent to the water-swellable rubber layer (A) and the water-insoluble rubber layer (B), laminating them to form a composite in a desired form, and then simultaneously combining them in accordance with a conventional method. Produced by vulcanization. The composite thus obtained can be put to practical use as a water-stopping material as it is. Further, the water-stopping material may be a water-opaque film pasted on the surface layer of the composite, and in this case, in practical use, the film is peeled off. There are no particular restrictions on the form of the waterproof material; for example, even if it is wound into a roll,
It may be in the form of a sheet. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Note that "parts" in Examples and Comparative Examples mean "parts by weight" unless otherwise specified. Example 1 100 parts of isobutylene-maleic anhydride copolymer (copolymerization molar ratio 1:1, molecular weight 160,000, manufactured by Clareisoprene Chemical Co., Ltd., Isoban-10), 42 parts of sodium hydroxide, and 260 parts of water were heated at 90°C. A homogeneous transparent aqueous solution of the sodium salt of the above copolymer was prepared by stirring and dissolving at a temperature. Next, 1.2 parts of glycerin diglycidyl ether having an epoxy equivalent of 145 was added to the aqueous solution to form a homogeneous mixture, and this solution was applied to a hot plate and dried. The obtained film was crushed to 20
After the powder was made into a powder that passed through a mesh sieve, it was heat-treated in a hot air dryer at 120°C to obtain a powdered super-absorbent resin with a water absorption capacity of 208 times. The powdered superabsorbent resin thus obtained and chloroprene (Neoprene W, manufactured by Showa Neoprene Co., Ltd.)
were mixed according to Table 1 and kneaded using an 8-inch open roll to prepare water-swellable rubber sheets (a, a') with a thickness of 1.5 mm.

[Table] On the other hand, water-insoluble rubber sheets (b, b') having a thickness of 1.5 mm were prepared by kneading with an 8-inch open roll according to the formulation shown in Table 2. In addition,
Although this sheet alone was vulcanized at 150℃ for 15 minutes,
The stress at 300% elongation was 66 Kg/cm ² .

[Table] The water-swellable rubber sheet (a) and the water-insoluble rubber sheet (b) were laminated and vulcanized for 15 minutes using a hot press at 150°C to produce a composite sheet (c). A test piece with a width of 15 mm and a length of 150 mm was cut out from the sheet (c) and evaluated as a waterproof material. The evaluation methods include a swelling test that examines the rate of increase in each length of the test piece in the length direction, width direction, and thickness direction when the test piece is immersed in water at 25°C for 7 days, and the above test piece 4. Glue the two sections together to form a picture frame, and
A water leak test was conducted under water pressure of 3 kg/cm ² as a water stop material for iron flange plates assembled to 4 mm. The results of the swelling test are shown in Table 3. As is clear from this, this water-stopping property has a relative ratio of the increase rate of length in the length direction, width direction, and thickness direction of about 1:
The ratio is 1:4, and the elongation in the length direction and width direction is suppressed to be smaller than the elongation in the thickness direction. Also, in the water leak test, no water leaks were observed.

[Table] Next, for comparison, a composite sheet was prepared by laminating the unvulcanized water-swellable rubber sheet (a') and water-insoluble rubber sheet (b') in the same manner as in the example. When we conducted a swelling test in the same manner as above, we found that a' and b' separated by the seventh day, and water leakage occurred in the water leak test, and a sufficient water-stopping effect could not be obtained. . From these results, it can be seen that if co-vulcanization is not performed, a product exhibiting sufficient water-stopping effect cannot be obtained. For reference, here is an example of a water-stopping material with a three-layer structure consisting of a composite made by laminating water-swellable rubber layers (A) on both sides of a water-insoluble rubber layer (B) and vulcanizing them simultaneously. A reference example is shown below. Reference Example A homogeneous aqueous solution was prepared by stirring and dissolving 100 parts of Isoban-10 as in Example, 42 parts of sodium hydroxide, and 260 parts of water at a temperature of 90°C. Next, 1.5 parts of glycerin diglycidyl ether with an epoxy equivalent of 140 was added to the aqueous solution and mixed thoroughly.
It was applied to a chrome-plated iron plate kept at ℃ and dried. The obtained film was crushed into a powder that passed through 20 mesh sieves, and then heat-treated in a hot air dryer at 120°C to obtain a powdered super absorbent resin with a water absorption capacity of 130 times. The powdered superabsorbent resin thus obtained and chloroprene rubber (manufactured by Showa Neoprene Co., Ltd., Neoprene W) with a crystallinity of 18% were blended according to Table 4.
After kneading with an inch open roll, a water-swellable rubber sheet (a ₁ ) with a thickness of 2.5 mm was produced.
In addition, the crystallinity of chloroprene rubber was measured using a differential scanning calorimeter (DSC).
It was determined by the method described on pages 138-139.

[Table] On the other hand, a water-inswellable gum sheet (b ₁ ) having a thickness of 2 mm was prepared by kneading with an 8-inch open roll according to the formulation shown in Table 5. In addition, 300% of this sheet alone was cured at 150℃ for 14 minutes.
The stress during elongation was 34 Kg/cm ² .

[Table] The water-swellable rubber sheet (a ₁ ) was layered on both sides of the water-insoluble rubber sheet (b ₁ ), laminated for 14 minutes using a hot press at 150°C, and vulcanized to form a composite sheet (c _{1 )} . ) was created. A test piece with a width of 15 mm and a length of 150 mm was cut out from the sheet (c ₁ ) and evaluated as a water stop material.
The evaluation method was the same swelling test as in the above example, and both sections of the above test piece were glued together to form a ring and used as a water stop material for a B-type humid pipe with a nominal diameter of 200 mm.
A water leak test under a water pressure of 2 kg/cm ² was adopted. The results of the swelling test are shown in Table 6. As is clear from this, this waterproof material has a relative ratio of increase in length in the length direction, width direction, and thickness direction of about 1:
The ratio is 1:3, and the elongation in the length direction and width direction is suppressed to be smaller than the elongation in the thickness direction, similar to the example. Further, in the water leak test, no water leaks were observed as in the examples.

【table】

Claims (1)

[Claims] 1. At least one group selected from a carboxyl group and a group that can be induced into a carboxyl group is added to a 1,3-diene rubber containing 5 to 50% crystalline or glassy area at room temperature. Powder consisting of a crosslinked product containing 40 mol% or more of α,β-unsaturated compound having 1 or 2 α,β-unsaturated compounds as a monomer component, and having a water absorption capacity of 20 to 500 times its own weight with respect to distilled water. a vulcanizing agent-containing water-swellable rubber layer (A) in which a vulcanizing agent-containing superabsorbent resin is dispersed; and a vulcanizing agent-containing water-inswellable rubber layer that absorbs expansion in directions other than the thickness direction due to water absorption of the rubber layer (A). A water-swellable water-stopping material for use between structures, made by laminating one layer each of (B) and simultaneously vulcanizing it.