JPH044244A - Water-swelling resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent physical strength even in non-crosslinked state, exhibiting high water-swelling ratio and suitable for water-stopping material by compounding a specific chlorinated straight-chain ethylene/alpha-olefin copolymer with a water-swelling resin. CONSTITUTION:The objective composition can be produced by compounding and homogeneously dispersing (A) 100 pts.wt. of a chlorinated straight-chain ethylene/alpha-olefin copolymer having a chlorine content of 5-40wt.% and a crystallinity of 0.1-3Cal/g and produced by chlorinating a straight-chain ethylene/alpha-olefin copolymer containing 2-40mol% of 3-12C alpha-olefins and (B) 10-400 pts.wt. of a water-swelling resin (e.g. crosslinked product of an alkali metal salt of a starch-acrylic acid graft polymer).

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention involves uniform cross-dispersion of a chlorinated linear ethylene/α-olefin copolymer having a specific degree of crystallinity and a water-swellable resin. The present invention relates to a water-swellable resin composition useful as a water-stopping material, etc.

(Prior art) Water-swellable resin compositions made from synthetic rubbers such as natural rubber or chloroprene rubber or thermoplastic elastomers and blended with water-swellable resins have traditionally been used for underground underground pipes. It has been used to prevent water leakage from gaps due to ground subsidence after construction, and as a segment water stop material in shield construction methods.

However, water sealing materials based on natural rubber or synthetic rubber generally require a vulcanization process, and therefore have drawbacks such as a decrease in the degree of water swelling of the water sealing material. was not satisfactory.

If the latter thermoplastic elastomer is used as the base material, it can be streamlined without requiring the vulcanization process of the water-stopping material, but if a large degree of water swelling is required, the physical strength of the water-stopping material after swelling may be reduced. It has been difficult to obtain a water-stopping material that satisfies both water swelling and physical strength.

Among these, a number of water-swellable water still forests have been proposed, which are made by blending superabsorbent resins with ethylene/α-olefin copolymers or chlorinated polyethylenes, which are chlorinated products thereof.

For example, in order to simultaneously achieve both high water swelling properties and shape retention properties in waterproof materials, it has been proposed to use EPR with a specific breaking strength. Since it absorbs water and swells with water in a non-crosslinked state, it maintains a certain degree of physical strength before water swelling, but has the disadvantage that the strength decreases significantly in a highly water swollen state.

It has also been proposed to use the same EPR and fill it with clay to a high degree and vulcanize it in order to further increase the physical strength after water swelling, but it has been difficult to obtain a sufficient degree of water swelling. In addition, in order to obtain a water-swellable waterproof material with excellent weather resistance and heat resistance, a proposal has been made to crosslink amorphous chlorinated polyethylene with peroxide; It showed only a degree of water swelling, which was not satisfactory.

(Problem to be solved by the invention) When water-swelling a water stop material formed by blending chlorinated polyethylene and a water-swellable resin with water in an uncrosslinked state, chlorination with a low degree of chlorination and high crystallinity occurs. Although polyethylene has excellent physical strength, its internal stress is greater than the water absorption and swelling pressure of water-swellable resins (as a result, the degree of water swelling of the stopper material is reduced, making it less effective as a water-swellable waterstop material). do not have.

On the other hand, if non-crystalline chlorinated polyethylene with a high degree of chlorination is used, not only the physical strength of the water-stopping material is low, but also the swelling pressure of the water-swellable resin becomes chlorinated when immersed in water. The cohesive force may be greater than that of polyethylene, causing it to lose its shape.

Furthermore, when such amorphous chlorinated polyethylene is used in a vulcanization system, it suffers from the same drawbacks as vulcanized rubber, and the water-swelling degree of the water-stopping material becomes extremely low.

In order to solve the above problem, the present inventors conducted intensive research and found that a specific chlorinated linear ethylene/α-olefin copolymer and a water-swellable resin were uniformly cross-dispersed and molded. The present invention was completed based on the finding that the water stop material has excellent physical strength and exhibits a high degree of water swelling even in a non-crosslinked state.

(Means for Solving the Problems) That is, the present invention provides an a-olefin having 3 to 12 carbon atoms.
Chlorinated linear ethylene with a chlorine content of 5 to 40% by weight and a crystallinity of 0.1 to 3.0 Cal/g obtained by chlorinating a linear ethylene/α-olefin copolymer containing ~40 mol%/ This is a water-swellable resin composition characterized by uniformly cross-dispersing an α-olefin copolymer and a water-swellable resin.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

Chlorinated linear ethylene/α-
The olefin copolymer is produced by suspending a specific ethylene/α-olefin copolymer in water and blowing chlorine into the suspension, as explained below.

Ethylene/α-olefin used as raw material for the composition of the present invention of ethylene α-olefin A
The a-olefin copolymerized with ethylene in the olefin copolymer has 3 to 12 carbon atoms. Specific examples include propylene, butene-1,4-methylpentene-1, hexene-1, octene-1, decene-12dodecene-1, and the like.

Particularly preferred among these are propylene, butene-1,4-methylpentene-1, and hexene-1.

Further, as a comonomer, dienes such as butadiene, 1,4-hexadiene, vinylnorbornene, ethylidene norbornene, etc. may be used in combination. Ethylene/α-
The α-olefin content in the olefin copolymer is 5 to 40
Preferably it is mol%.

First, the catalyst system used is a combination of a solid catalyst component containing at least magnesium and titanium with an organoaluminum compound, and examples of the solid catalyst component include magnesium metal, magnesium hydroxide, magnesium carbonate, magnesium oxide, and chloride. Oxygen-containing compounds such as magnesium, double salts, double oxides, carbonates, chlorides, hydroxides, etc. containing a metal selected from silicon, aluminum, and calcium and magnesium atoms, and further inorganic solid compounds thereof Examples include those in which a titanium compound is supported by a known method on an inorganic solid compound containing magnesium, such as one treated or reacted with a sulfur-containing compound, an aromatic hydrocarbon, or a halogen-containing substance.

Specific examples of these catalysts include, for example, 1Mg0
-RX-TiC14 system (Special Publication No. 51-3514)
, Mg-3iC14-ROH-TiC1, system (Japanese Patent Publication No. 50-23864), MgC1z-Al (OR
) s-TiC14 series (Japanese Patent Publication No. 51-152, Japanese Patent Publication No. 52-15111), MgCl2-3iC1
4-ROH-TiC1, system (JP-A-49-106581
No. Publication), Mg(OOCR)z-Al(OR)x-T
iC14 series (Special Publication No. 52-11710), M
g-POClj-TiC1, system (Japanese Patent Publication No. 51-153), MgC1, -A10CI-TiC1, system (Japanese Patent Publication No. 54-15316), MgC12-Al(O
R), X3-n-3i (OR'), nX4-6-TiC
A preferred catalyst is a combination of a solid catalyst component (in the above formula, R and R' are organic residues and X is a halogen atom) such as 14 series (Japanese Unexamined Patent Publication No. 56-95909) and an organoaluminium compound. This is an example of a system.

Another example of a catalyst system is a catalyst system in which a reaction product of an organomagnesium compound such as a so-called Grignard compound and a titanium compound is used as a solid catalyst component, and an organoaluminum compound is combined therewith.

As the organomagnesium compound, for example, shipyard RMg
Organomagnesium compounds such as X, RJg, RMg (OR) (where R is an organic residue having 1 to 20 carbon atoms, Furthermore, compounds modified by adding various other organic metal compounds such as organic sodium, organic lithium, organic potassium, organic boron, organic calcium, and organic zinc can be used.

Specific examples of these catalyst systems include, for example, RMgX-
TiC14 series (Special Publication No. 50-39470), R
MgX-Phenol-TiC14 system (Special Publication Publication No. 54-12
953), RMgX-A rogogenated phenol-T
i C14 series (Special Publication No. 54-12954),
RMgX-CO□-TicL series (JP-A-57-730
Examples include those in which an organoaluminum compound is combined with a solid catalyst component such as in Japanese Patent No. 09).

In addition, as an example of another catalyst system, as a solid catalyst component, 5
iOa, A1.0. For example, a solid material obtained by contacting an inorganic oxide such as the above solid catalyst component containing at least magnesium and titanium with an organoaluminum compound can be used.

Specific examples of these catalyst systems include, for example, SiO□-
ROH-MgC1a-TiC14 series (JP-A-56-47
407), StO□-R-0-R-MgO-
AIClx-TiC14 series (JP-A-57-187305
No. Publication), 5102-MgCl2-Al (OR)
m-TiC1, -Si (OR') 4 series (Unexamined Japanese Patent Publication No. 1983
21405) (in the above formula, R1R' represents a hydrocarbon residue), etc., in combination with an organoaluminum compound.

Specific examples of organoaluminum compounds to be combined with the above-mentioned solid catalyst components include - Shipura R, A1. R
,AIX, l'1AIX, ,R,A10R,RAlf
OR) Organoaluminum compound of X and R, A1□x3 (where R is an alkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms, X is a halogen atom, and R may be the same or stationery) Preferably, the compound represented by
Examples include triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminium chloride, diethylaluminum ethoxide, ethylaluminum sesquichloride, and mixtures thereof.

The amount of the organoaluminum compound to be used is not particularly limited, but it can usually be used in an amount of 0.1 to 1.000 times the mole of the titanium compound.

Furthermore, by contacting the catalyst system with an α-olefin and then using it in the polymerization reaction, the polymerization activity can be greatly improved and the system can be operated more stably than an untreated system. Various α-olefins can be used at this time, but α-olefins having 3 to 12 carbon atoms are preferred, and α-olefins having 3 to 8 carbon atoms are more preferred. Examples of these α-olefins include propylene, butene-1, pentene-1,4-methylpentene-1, hexene-1, octene-1, decene-1, dodecene-1, etc., and mixtures thereof. can be mentioned.

The temperature and time during contact between the catalyst system and the α-olefin can be selected within a wide range. For example, the contact treatment can be carried out at 0 to 200°C, preferably 0 to 110°C, for 1 minute to 24 hours. The amount of α-olefin to be contacted can be selected within a wide range, but is usually 1 g per 1 g of the solid catalyst component.
It is desirable to treat with about 50.000 g, preferably 5 g to 30,000 α-olefin, and react 1 g to 500 g of α-olefin per 1 g of the solid catalyst component. At this time, the pressure at the time of contact can be arbitrarily selected, but it is usually desirable to bring them into contact under a pressure of -1 to 100 kg/crtr.G.

During α-olefin treatment, the entire amount of the organoaluminum compound used may be combined with the solid catalyst component and then brought into contact with the α-olefin, or a part of the organoaluminum compound used may be combined with the solid catalyst component. After combining with α-olefin, the remaining organoaluminum compound may be added separately during polymerization to carry out a polymerization reaction.

Furthermore, when the catalyst system and the α-olefin are brought into contact, there is no problem if hydrogen gas coexists (and there is no problem if other inert gases such as nitrogen, argon, helium, etc. coexist). The reaction is carried out in the same manner as the ordinary polymerization reaction of olefins using Ziegler-type catalysts.That is, the entire reaction is carried out in a state substantially free of oxygen, water, etc., in the gas phase, in the presence of an inert solvent, or using the monomer itself as a solvent. The olefin polymerization conditions are as follows: temperature is 20-300°C, preferably 40-200°C.
00℃, and the pressure is normal pressure ~ 70K g/crd・G
, preferably 2Kg/crrr-G to 60Kg/crt
It is r.G. Although the molecular weight can be adjusted to some extent by changing polymerization conditions such as polymerization temperature and catalyst molar ratio, it is effectively carried out by adding hydrogen to the polymerization system.

Of course, a two-stage or more multi-stage polymerization reaction with different polymerization conditions such as hydrogen concentration and polymerization temperature can also be carried out without any problem. Among these, the gas phase polymerization method is preferred.

The linear ethylene/α-olefin copolymer, which is a preferred raw material of the present invention, is produced by combining ethylene and α-olefin in the presence of a small amount (both of which are composed of a solid catalyst component containing magnesium and titanium and a catalyst consisting of an organoaluminum compound). It is obtained by copolymerization, and its preferred physical properties are as follows.

That is, the melt index (measured according to JIS K6760 at 190°C and 2.16 kg, hereinafter referred to as rM
(referred to as IJ) Ha0. Ol~100 g/l 0ml
n, preferably 0.1 to 50 g/min.

It is. Density (according to JIS K6760) is 0.86
0-0.910 g/crrr, preferably 0.870
~0.905g/c+yf, more preferably 0880~
It is 0.900g/crri'. Maximum peak temperature (Tm) measured by differential scanning calorimetry (DSC) is 100°C
Above, preferably 110 ° C., boiling n-hexane insoluble content is 10% by weight or more, preferably 20 to 95% by weight,
More preferably, it is 30 to 90% by weight.

MI of ethylene/α-olefin copolymer is 0.01g
If it is less than 710 m1n, the fluidity will decrease, and if the MI is less than 1
If it exceeds 00 g/10 m1n, the tensile strength etc. of the chlorinated product will decrease, which is not desirable.

Chlorination of ethylene a-olefin 4 A known method can be used to chlorinate the linear ethylene/α-olefin copolymer used in the present invention. For example, a powdered polymer is suspended in water and the temperature is adjusted to about 70 to 80°C, preferably 90°C under appropriate pressure.
An aqueous suspension method in which the polymer is reacted with chlorine by keeping it at 0°C or above, a method in which the polymer is dissolved in an organic solvent such as tetrachloroethylene and the polymer is reacted with chlorine, or a method in which a chlorine compound such as N-chloroacetamide is reacted with the polymer in advance. There are methods such as blending it with a polymer, heating it to a temperature at which the chlorine compound decomposes and liberates chlorine, and reacting the liberated chlorine with the polymer. In particular, a chlorination method using an aqueous suspension method is preferred.

The chlorinated linear ethylene/α-olefin copolymer used in the present invention has a crystallinity of 0.1 to 3 and an OCa
It is important that the ratio is 1/g. A stopper made of a non-quality chlorinated linear ethylene/α-olefin copolymer having substantially no crystallinity is not preferred because it exhibits cold flow properties.

Since the fastener made of the water-swellable resin composition of the present invention is used without being crosslinked or vulcanized, an important characteristic is that it has no cold flow properties. In addition, the crystallinity is 3,
If it is larger than OCal/g, the elongation of the water stopper material will be poor and the degree of water swelling as a water stopper material will be lowered, which is also not preferable.

The chlorine content of the chlorinated linear ethylene/α-olefin copolymer of the present invention is 3 to 50% by weight, preferably 5% by weight.
~40% by weight, and if it is less than 5% by weight, it is difficult to mix uniformly with the water-swellable resin, while if it exceeds 40% by weight, the heat resistance and low-temperature properties of the anchoring wood will deteriorate. I also don't like it.

The reason why the chlorinated linear ethylene/α-olefin copolymer used in the present invention is preferable is considered to be due to the following reasons.

In other words, the low-density ethylene/a-olefin copolymer before chlorination has a high degree of branching, so it has many amorphous parts and is soft, and has microcrystalline parts, so it is difficult to flow and deform near room temperature. do not have. The amount of microcrystals can be adjusted as desired by controlling the amount of α-olefin as a comonomer or by other means. In order to maintain this characteristic without disappearing during chlorination, chlorination by an aqueous suspension method is preferable.

In other words, fine particles dispersed in water at a temperature below the melting point of the low-density ethylene/α-olefin copolymer are chlorinated only on the surface, and most of the crystals in that area disappear, but chlorination does not proceed to the inside. It is thought that a microcrystalline state remains.

For these reasons, chlorinated low-density ethylene/α-olefin copolymers are considered suitable for the purpose of the present invention. Although it is possible to leave a certain amount of crystals in other high-density and low-density polyethylenes when chlorinating them, satisfactory results cannot be obtained when used as a base material for the composition of the present invention. It is thought that there is a difference in condition.

The above-mentioned preferred ethylene/α-olefin copolymer of the present invention has an appropriate amount of microcrystalline portion and other properties, so if its chlorinated product is blended with a water-swellable resin, the resulting composition Water-stopping materials are preferable because they have appropriate shape retention properties.

The water-swellable resin used in the present invention and which is the second characteristic of the present invention may be any conventionally known resin, for example,
Saponified products of starch/acrylonitrile graft copolymers, crosslinked products of alkali metal salts of starch/acrylic acid graft polymers, crosslinked products of acrylic acid-acrylic acid alkali metal salt copolymers, ethylene-vinyl ester-acrylic acid ester copolymers Any of the conventionally known products such as saponified polymers, crosslinked products of alkali metal salts of inbutylene-maleic anhydride copolymer, crosslinked products of alkali metal salts of carboxymethylcellulose, crosslinked polyethylene oxide, water-swellable polyurethane resins, etc. can also be used.

Particularly preferred water-swellable resins in the present invention are block copolymers or graft copolymers of hydrophobic polymer segments and hydrophilic polymer segments. For example, Japanese Patent Publication No. 56-50886, Japanese Patent Publication No. 56-5
Publication No. 4002, Japanese Patent Publication No. 57-48001, Japanese Patent Publication No. 57-48008. It is stated in the No. Most preferred among such block or graft copolymers are those in which the hydrophilic group of the hydrophilic polymer segment is an alkali metal salt of a carboxylic acid or a sulfonic acid.

The above-mentioned water-swellable resins each have their own characteristics in terms of water swelling degree, water absorption rate, gel strength, and degree of water swelling in salt-containing water such as seawater and groundwater. May be used in combination. The usage ratio can be arbitrarily selected depending on the required degree of water swelling and usage environment.

The chlorinated linear ethylene/α-olefin copolymer and the water-swellable resin used in the present invention can be blended in any ratio, but the degree of water swelling and physical It is preferable to mix 10 to 400 parts by weight of the water-swellable resin per 100 parts by weight of the chlorinated linear ethylene/α-olefin copolymer, which is selected depending on the strength and the intended use. If the water-swellable resin is less than 10 parts by weight, the water-swelling degree of the obtained fastening piece will be low and it is not practical. On the other hand, if the amount exceeds 400 parts by weight, the physical strength of the anchoring piece will be insufficient and the water-swellable resin powder will be present in excess, impairing workability and moldability.

The essential components of the water-swellable resin composition of the present invention are as described above, but within the range that does not change the performance as a water-stopping material, conventionally known high-density polyethylene, linear low-density polyethylene,
High-pressure polyethylene, crystalline polyolefins such as polypropylene or their chlorinated products, natural rubber, various synthetic rubbers, thermoplastic elastomers, conventionally known crosslinking agents for chlorinated polyethylene, plasticizers, process oils, polybutene, carbon black, various dyes. Pigments, various fillers such as calcium carbonate and clay, reinforcing agents, stabilizers, anti-hyperoxidants,
Ozone deterioration inhibitors, flame retardants, foaming agents, etc. can be optionally added as necessary.

Each of the above components can be easily uniformly dispersed by using a conventionally known kneading machine such as a two-roll mixer, a Banbury mixer, or a kneader 1 extruder. These mixed materials are molded using any known molding machine. For example, a string-like or sheet-like waterproof material can be obtained by using an ordinary extrusion molding machine. In addition, water swelling of arbitrary shapes can be achieved by creating wide sheets by using calender rolls, molding O-rings etc. by injection molding, and obtaining molded products with various complicated shapes by press molding. A molded article of the resin composition can be obtained.

(Action/Effect) The water-swellable resin composition obtained by the present invention is based on a chlorinated linear ethylene/α-olefin copolymer obtained by chlorinating a specific ethylene/α-olefin copolymer. Although it does not require a vulcanization process or crosslinking with peroxide, it has excellent physical strength, has a fast water swelling rate, and exhibits a high degree of water swelling. .

In particular, when used as a water-stopping material for joints of underground pipes, PVC pipes, etc., it has a large volumetric swelling even if a large gap is created due to unevenness, so it is easily The gap is closed and water leakage is prevented.

In addition, when used as a segment waterproofing material for a deep shield, it has a swelling pressure that can withstand the large water pressure underground, so it can prevent groundwater from penetrating into the shield.

The water-swellable resin composition of the present invention preferably has excellent properties because it involves a combination of a chlorinated product of a specific linear ethylene/α-olefin copolymer and a specific water-swellable resin composition. . In particular, since the water-swellable resin composition of the preferred combination of the present invention is used without crosslinking or vulcanization, it has excellent affinity between chlorinated substances and water-swellable resin, especially when immersed in water. For example, the water-swellable resin does not come off when immersed in water.

In addition to being used as a water-stopping material, the water-swellable resin composition of the present invention can also be advantageously used in other applications such as water-containing cold insulation materials, soil water retention materials, dew prevention materials, and water-absorbing mats. .

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight. In addition, the degree of water swelling is as follows (
This is the value calculated using

Water swelling degree = weight of sample after water absorption/dry weight of sample Also, the chlorinated linear ethylene/α-olefin copolymer and water-swellable resin used in Examples and Comparative Examples were manufactured by the following manufacturing method. It is what was done.

Ethylene α-olefin f A Copolymerization of ethylene and butene-1 using a solid catalyst component obtained from substantially anhydrous magnesium chloride, 1,2-dichloroethane, and titanium tetrachloride, and a catalyst consisting of triethylaluminum. Ethylene/butene obtained by
1 copolymer resin was mechanically pulverized at room temperature to a particle size that could pass through a 32-mesh wire mesh.

5 kg of this ethylene/butene-1 copolymer resin powder was placed in a glass-lined autoclave with an internal volume of 100 I2, 70 β of ion-exchanged water, 2 g of wetting agent, and 200 m of dispersant.
100 while stirring and blowing in chlorine gas.
The reaction was started at .degree. C., and chlorination was carried out while maintaining the same temperature until a predetermined chlorine content was reached, followed by washing with water and drying by a conventional method. Samples with a chlorine content of 15% and 30% were prepared. The crystallinity was determined to be 2.2 and 1 by DSC method, respectively.
, 8 Cal/g.

The physical properties of the ethylene/butene-1 copolymer, which is the raw material before chlorination, are as follows.

Density: 0.905 g/c Bobten-1 content = 7.7 mol% Melt index: 1.0 g 710 ml Maximum peak temperature of DSC = 122°C Boiling n-hexane insoluble content: 94% by weight Boiling n-hexane in the present invention Insoluble matter and DSC
The measurement method is as follows.

(Method for measuring boiling n-hexane insoluble content) A sheet with a thickness of 200 μm is formed using a heat press, and 3 sheets of 20 mm x 30 mm in length and width are cut out from it.
Extraction is carried out with boiling n-hexane for 5 hours using a double-tube Waxley extractor. After taking out the n-hexane insoluble content and vacuum drying (7 hours under vacuum, 50°C), the boiling n-hexane insoluble content (X, weight %) is calculated using the following formula.

(Measurement method using DSC) From a 100 μm thick film formed by heat press, about 5
Weigh exactly 1 mg of sample, set it in the DSC device, and
After raising the temperature to 70°C and maintaining that temperature for 15 minutes, it was cooled to 0°C at a cooling rate of 25°C/min. Next, from this state, the temperature is raised to 170°C at a heating rate of 1°C/min, and measurements are taken. with T
Let it be ffi.

Mokubuta Seinikotsu (polystyrene)-(polybutadiene)-(polystyrene) block copolymer (polystyrene content 30%)
By adding thioglycolic acid to almost all the double bonds of
A water-swellable resin A (water absorption capacity: 150 times) made into a sodium salt of carboxylic acid was obtained.

Acrylic acid-sodium acrylate (75% mole of carboxylic acid of acrylic acid neutralized with caustic soda) was prepared by adding potassium persulfate, N,N'-methylenebisacrylamide, and cyclohexane-sorbitan monostere was prepared. It was added dropwise to the rate solution while stirring to prepare a suspension. Next, the mixture was reacted at 60° C. for 6 hours, cyclohexane was distilled off, and dried under reduced pressure at 70”C to obtain water-swellable polymer B (water absorption: 400 times).

Example 1 75 parts of water-swellable resin A to 100 parts of chlorinated linear ethylene/α-olefin copolymer with a chlorine content of 15%,
Two parts of the tin-based stabilizer were kneaded using two rolls. Next, the obtained kneaded product was press-molded for 3 minutes at 160° C. and 150 kg/crrf to obtain sheets with thicknesses of 1 mm and 3 mm.

The tensile strength and other physical properties of the 1 mm thick sheet were measured based on JIS K-6301. A sheet with a thickness of 3 mm was cut into a size of approximately 1 cm square, and the degree of water swelling in distilled water was measured. The result is the first
Shown in the table.

Examples 2 to 8 The same operation as in Example 1 was carried out with the formulations changing the degree of chlorination of the chlorinated linear ethylene/a-olefin copolymer, the water-swellable resin, and the amount added thereof as shown in Table 1. The process was repeated to create a sheet, and its physical properties and degree of water swelling were measured. The results are shown in Table 1.

Comparative Examples 1 to 2 Using chlorinated polyethylene with a chlorine content of 30% and a crystallinity of 3.4 Cal/g, which was produced by chlorinating high-density polyethylene according to the above-mentioned aqueous suspension method, A sheet was prepared by repeating the same operations as in Example 1 using the formulations shown in Table 1. The results are shown in Table 1.

Example 9 In order to evaluate the performance of the water-swellable resin compositions obtained in Examples and Comparative Examples, a water stop pressure test device consisting of two iron discs was created. The test equipment is mainly made of steel and has a thickness of 20 mm.
It consists of two circular flat plates and a water supply pressure pump, and a sealing groove is provided in the circular flat plate on the lower surface.

The mixed wires obtained in Example 2 and Comparative Example 1 were used in a 60 mm extruder to obtain string-like water-swellable stoppers having a cross section of 20 mm in width and 3 mm in thickness.

By pasting the above water-swellable water stop material on the lower seal groove of the test device with epoxy adhesive and placing a 2 mm spacer on the flat part between the top and bottom surfaces, a distance of 1 m between the top surface and the water stop material was created.
A clearance of m was provided.

The upper and lower parts of the test device were tightened with dowel bolts, a water supply pressure pump was set, a predetermined pressure was applied, and the presence or absence of water leakage was observed over time. The results are shown in FIG. As is clear from the figure, it was able to withstand water pressure of 7KG/crrr even after 9 months.

The water-swellable waterproof material obtained by the present invention swells with water despite the presence of a clearance of 1 mm relative to the thickness.
The increase in volume closes the voids. Furthermore, as the water-swellable resin contained swells with water, the water-swellable water stop material sandwiched between the two upper and lower discs exhibits a high swelling pressure with respect to the discs. As a result, it can withstand high water pressure and can be used for construction work several tens of meters underground.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between pressure and water leakage in Example 9.

Claims (1)

[Claims] (1) A linear ethylene/α-olefin copolymer containing 2 to 40 mol% of an α-olefin having 3 to 12 carbon atoms is chlorinated to have a chlorine content of 5 to 40% by weight and a crystallinity of 0.
A water-swellable resin composition characterized by uniformly cross-dispersing a chlorinated linear ethylene/α-olefin copolymer of 1 to 3.0 Cal/g and a water-swellable resin.