JPS62109883A - Water-swelling composition - Google Patents

Abstract

PURPOSE:To provide the titled composition containing a water-swelling substance, hydraulic cement, quick hardening agent for cement, rubber and gypsum, exhibiting low shrinkage by drying after dilation with water, having excellent water-stopping performance and useful as a water-stopping material, packing material, etc. CONSTITUTION:The objective composition contains (A) a water-swelling substance (preferably a substance which can be kneaded with rubber or elastomer, e.g. water-swelling urethane resin, etc.), (B) a hydraulic cement (e.g. Portland cement), (C) a quick hardening agent for cement (e.g. calcium aluminate-type inorganic substance such as 3CaO.Al2O3, CaO.Al2O3, 12CaO.7Al2O3, etc.), (D) a rubber and (E) gypsum. The sum of the components B+C+E is preferably 50-300pts. per 100pts. of A+D and the amount of the component C is 40-100pts. per 100pts. of the component B.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water-swellable composition, and particularly relates to a water-swellable composition that absorbs water and expands, and then shrinks little even when dried. .

[Prior art and problems]

Conventionally, water-swellable sealants have been made by adding water-absorbing substances such as sodium polyacrylate, starch, carboxymethyl cellulose, and polyethylene glycol to rubber or plastic to give them water-swellability. All of these shrink to almost their original state when dried. In addition, these water-swellable sealants are
Since the water-absorbing substance is water-soluble and elutes, the water swelling rate gradually decreases.

Furthermore, when these water-swellable sealants come into contact with seawater, they expand less than half as much as they do with fresh water.

As a water-swellable composition that solves the above problems, the present inventors have already proposed in Japanese Patent Application No. 59-92048 a water-swellable composition containing a water-swellable substance and a hydraulic substance as essential components. This composition has the remarkable effect of reducing drying shrinkage after it absorbs water and expands, but it has a problem in that its rubber elasticity deteriorates after a long period of time in a weakly restrained state in water. Was.

[Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive research in order to improve the above problems.

That is, the water-swellable composition of the present invention comprises a water-swellable substance (I),
Hydraulic cement (II), cement quick hardening agent (IIT)
, rubber (IV), and gypsum (V).

[For production]

In the present invention, the water-swellable substance (I) can be appropriately selected depending on the purpose of use of the composition, but it is preferably one that can be kneaded with rubber and/or elastomer (hereinafter referred to as rubber etc.). Urethane resins, carboxymethyl cellulose, polyvinyl alcohol, polyethylene glycol, hydroxyethyl cellulose, methyl cellulose, etc. can be used alone or in combination, and in addition, those commonly called water-absorbing resins can also be used. Among them, water-swellable urethane resins are preferred.

The water-swellable urethane resin is preferably a paste or an elastomer when mixed with a hydraulic substance, and a paste is particularly preferred.

Examples of pasty water-swellable urethane resins include resins obtained by reacting a water-swellable polyurethane prepolymer containing terminal isocyanate groups with water and/or a curing agent.

The water-swellable polyurethane prepolymer containing terminal isocyanate groups has a hydroxyl equivalent of 400 to 600, for example.
A propylene oxide/ethylene oxide ratio of 7/3 to 7/3 obtained by reacting 0 ethylene oxide/propylene oxide random/block polymerized polyoxyalkylene glycol with an organic diisocyanate in a conventional manner.
0/10 prepolymer is mentioned.

The prepolymer can be partially cured by a conventional method using water or an amine-based or polyol-based curing agent to form a water-swellable polyurethane resin in the form of a paste. Curing may be carried out using a combination of water and a curing agent. As a curing agent, 4.4'-methylene-bis-2-chloroaniline,
114-butanediol, hydroquinone-bis-(β
-hydroxy)ether, resorcinol-bis-(β
-hydroxy) ether, 1,2-bis-(2-7 minophenolthio)ethane, trimethylene glycol di-p-aminobenzoate, etc. can be used alone or in combination.

Here, water-absorbing resins that are usually referred to as resins include carboxyl groups, carboxylic acid salts, carboxylic acid amides, carboxylic acid imides, carboxylic acid anhydrides, and other groups that have a carboxyl group or a group that can be derived into a carboxyl group in the molecule. The main component is one or two α,β-unsaturated compounds, and if necessary, other α,β-unsaturated compounds are added and polymerized, or these are further modified with isocyanates, etc. It will be done.

Examples of such water-absorbing resins include starch/acrylic acid graft copolymers, salts of styrene-maleic anhydride copolymers, crosslinked products of sodium polyacrylate, crosslinked products of polyvinyl alcohol/maleic anhydride reactants, and vinyl Known super absorbent polymers such as saponified products of esters/ethylenically unsaturated carboxylic acids or derivatives thereof can be used.

In addition, in the present invention, the hydraulic cement (II) includes various portland cements such as ordinary, white, early strength, etc.
Special cement such as blast furnace cement, colloidal cement classified by particle size, etc. can be used as appropriate.

As the cement quick hardening agent (I[I), calcium aluminate-based inorganic substances, namely 3CaO.^I2O3, CaO-
A1zO+ , 12CaO' 7AIZO3,C
Ca such as aO・281203, CaO・681□03
Examples include fired products and molten mixtures of O and AIto, and commercially available products include Denka ES (part name manufactured by Denki Kagaku ■).

The content of the water-swellable substance N) is preferably such that the water swelling rate of the molded article obtained from the water-swellable composition is 20 to 350 (volume)%, and is 40 to 250 (volume)%. More preferably, the amount varies. In particular, when the water-swellable substance (I) is a water-swellable urethane resin, 20 to 150 parts of the water-swellable urethane resin are added to 100 parts (by weight, the same applies hereinafter) of the rubber (IV).
Preferably, 30 to 120 parts are used.

The rubber (TV) used in the present invention includes natural rubber, synthetic rubber, or recycled rubber, such as natural rubber, styrene-butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene terpolymer, butyl rubber, etc. It is selected from among these recycled rubbers depending on the use and purpose.

In the present invention, an elastomer can be used in addition to the above-mentioned rubber, and such elastomers include polyurethane, polyolefin, polystyrene, and the like.

Furthermore, in the present invention, gypsum (V) is used as an essential component.

Furthermore, the compositions of the invention can contain inorganic additives. The inorganic additives are preferably finely pulverized so as to be added to rubber, and preferable are white powder, zinc white, finely powdered silica, magnesium carbonate, etc., as well as bentonite, clay, other calcium silicates, alumina, chalk, etc. Can be added. Depending on the purpose, fillers such as glass microspheres, glass fibers, and carbon fibers may also be added in appropriate amounts.

By adding such inorganic additives, the mixability and moldability of the present composition can be facilitated, or the physical properties of the molded article, particularly the strength and elasticity, can be improved.

The contents of hydraulic cement (II), cement hardening agent (I[I), and gypsum (V) can be appropriately selected in relation to the water swelling rate and physical properties of the molded article of the water-swellable composition of the present invention. but,
Total of water-swellable substances (r), rubber (IV), etc. 1100
The total amount of hydraulic cement (II), cement hardening agent (II[), and gypsum (V) is preferably 50 to 300 parts.

Further, 20 to 150 parts of the cement quickening agent (Ill) is preferably used, particularly preferably 40 to 100 parts, per 100 parts of the hydraulic cement (n).

Furthermore, 5 to 100 parts of gypsum (■) is preferably used, particularly preferably 10 to 80 parts, per 100 parts of hydraulic cement (II).

In addition, when the water-swellable composition of the present invention is molded, as the shape becomes larger (this refers to the case where the thickness increases),
The amounts of hydraulic cement (■), cement hardening agent (III) and gypsum (V) can be reduced.

Expressed in terms of the thickness of the molded product, the amount of the above-mentioned hydraulic substance added per 100 parts of rubber, etc. is, if the molded product is 5 mm or less,
100-300 parts, preferably 150-270 parts, 5-300 parts
b Preferably 130 to 240 parts, 1 in case of 10 mm or more
00 to 200 parts is preferable.

Moreover, when using a molded article, the amount of the above-mentioned hydraulic substance can be reduced as the degree of restraint is greater.

The water-swellable composition of the present invention is preferably compounded using a common rubber mixing machine such as a roll, kneader, or Banbury mixer, and then molded using an extrusion molding machine or a press molding machine.

In this case, does it create a bridge between molecules? It is preferable to add J quality because it improves the physical properties of the molded product. Also,
The surface of the thus obtained molded article is preferably coated with an adhesive, a coating agent, an anti-aging agent, an expansion regulator, etc. depending on the purpose of use.

Substances that cause cross-linking between molecules used in the present invention include water-swellable substances and substances that can cause cross-linking between each molecule of rubber, such as sulfur, sulfur chloride, and organic peroxide. oxides, organic sulfur compounds, metal oxides,
Rubber vulcanizing agents such as alkylphenol resins, polythiol compounds, polyamine compounds, azo compounds, etc. can be used. Particular preference is given to crosslinking with sulfur and organic peroxides.

Sulfur is preferably powdered sulfur, and suitable organic peroxides include benzoyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide, cyclohexanone peroxide, L-butyl perbenzoate, t-butyl hydroperoxide, t-
Examples include butylhenzen peroxide, cumene hydroperoxide, t-butyl peroctoate, and the like.

Suitable organic sulfur compounds include tetramethylthiuram disulfide (TT), N,N''-dithiobismorpholine, and the like.

Suitable metal oxides include zinc white, magnesia, litharge, and the like.

Suitable alkylphenol resins include alkylphenol formaldehyde resins containing 7 to 10% methylol groups.

Suitable polythiol compounds include trimethylolpropane trithioglycolate, trimethylolpropane tri(3-mercaptopropionate), glycol dimercaptoprobionate, glycol dimercaptoacetate, pentaerythritol tetra(3-mercaptopropionate). , pentaerythritol tetrathioglycolate, dipentaerythritol hexa(3-
mercaptopropionate), etc.

Suitable polyamine compounds include aldehyde-amine condensates, guanidines, and the like.

Suitable azo compounds include azobisisobutyronitrile, 2-t-butylazo-2-cyano-4-methylpentane, 4-t-butylazo-4-cyano-valeric acid, and the like.

The above-mentioned crosslinking agents can be used alone or in a suitable combination of two or more, and the appropriate blending amount is 0.5 to 10 parts per 100 parts of rubber.

The water-swellable composition of the present invention is generally preferably manufactured as follows.

Add the water-swellable substance (I) to the rubber (IV) and add the hydraulic cement (N) at the same time or after adding (I).
II), cement quick hardener (I [I), gypsum (■), inorganic additives, etc. are added, and if necessary, vulcanization accelerator, vulcanization aid,
Kneading is carried out using a kneading roll, a Banbury mixer, etc. to mix general rubber compounding agents such as softeners, anti-aging agents, and adhesives. Next, a crosslinking agent is added and molded by pressing, or extrusion followed by vulcanization treatment (usually at 100°C or higher).
A molded product of the water-swellable composition is obtained.

The vulcanization treatment is not limited to heat vulcanization, steam vulcanization, or hot air vulcanization, but may also be natural vulcanization, hot water vulcanization, or cold vulcanization.

When a crosslinking agent is used, the water-swellable composition is characterized in that the water-swellable substance (I) and the rubber (IV) are crosslinked together as one body.

〔Effect of the invention〕

The water-swellable composition of the present invention has excellent water-swellability, excellent mechanical properties and water-stopping properties as a molded article, and can be used in a wide range of applications as stoppers, backing materials, and the like.

The water-swellable composition of the present invention has good stability in water because it absorbs water and forms a skeleton (matrix) of a condensed water-hard substance.
It shrinks little even when dried and does not lose its elasticity over a long period of time. Furthermore, the same degree of swelling can be obtained even in seawater as in freshwater.

〔Example〕

Hereinafter, the present invention will be explained in further detail with reference to Examples.

Examples 1 to 5 and Comparative Examples 1 to 2 The formulations shown in Table 1 (unit: parts by weight) were kneaded using a 20CTI+ oven roll to create blended products 1 to 7.

(Note) *1 Urethane prepolymer 50 obtained by reacting 1 mole of polyether with an average molecular weight of 500 and 78% ethylene oxide groups, which is obtained by adding ethylene oxide and propylene oxide to water-swelling urethane resin propylene glycol, and 3.0 moles of TDI. 5 parts of 40% MOCA were reacted at 40°C to obtain a paste-like urethane resin of 6000 cps at the same temperature.
I used this.

Umbrella 2 Calcium sulfoaluminate cement quick hardener, Denka ES (electrochemical part name) Car 3 Stabilizer diphenylguanidine *4 Vulcanization accelerator N-cyclohexyl-2-pentthiazole sulfenamide This compound was heated to 140℃ Pressing was carried out for 10 minutes to obtain a 2-inch thick sheet. The sheet was examined for blooming and subjected to a tensile test (measurement method: JIS K 6301).

Further, a long product with a cross-sectional area of 20×5 (mm) was produced by extrusion, and the swelling ratio (%) when immersed in water, the elasticity after 100 days, and the swelling ratio after 10 days of drying were measured. Table 2 shows the results.
Shown below.

In addition, Comparative Examples 1 and 2 were blended products that did not use gypsum.

Claims (1)

[Claims] The essential components include water-swellable substances (I), hydraulic cement (II), cement quickening agents (III), rubber (IV),
and gypsum (V).