JPH01245081A - Water-stopping material swelling with water and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject material having excellent durability and high swellability even in an aqueous solution of electrolyte and useful as a sealant for crack of concrete by reacting a polyoxyalkylene glycol with an isocyanate. CONSTITUTION:The objective material can be produced by uniformly mixing an elastomer, a filler and a polyoxyalkylene glycol containing 50-90wt.% of oxyethylene unit to obtain a uniform mixture A, adding (B) an isocyanate composed of a diisocyanate and a polyisocyanate having >=3 functionality at a ratio NCO:OH of (1.1-2.5):1 based on the hydroxyl group of the component A, reacting the component A with the component B to form a crosslinked material consisting of the component A and the component B and vulcanizing the resultant composition.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water-swellable water-stopping material and a method for producing the same;
More specifically, the water-swellable water-stopping material is highly durable, has good swelling performance even in electrolyte aqueous solutions, exhibits excellent water-stopping effects, and can be produced industrially advantageously, and its production. It is about the method.

[Prior Art] Conventionally, water-stopping materials have been used mainly in the civil engineering and construction fields to fill cracks after concrete construction and gaps between joints of concrete products to prevent water from leaking from the cracks or gaps. used for. Conventionally used water-stopping materials include, for example, elastomers mixed with highly water-absorbent resins along with fillers, anti-aging agents, vulcanizing agents, vulcanization accelerators, etc., which are then molded and vulcanized. something is proposed. (For example, JP-A-57-10
(No. 8143) However, the super water-absorbing resins that are blended into such conventionally commonly used water-stopping materials utilize the water-absorbing ability of weakly anionic electrolytes, and although they have a high water-absorbing ability, The water absorption capacity for electrolyte aqueous solutions such as seawater is significantly lower than that for water. For this reason, water-stopping materials containing such superabsorbent resins have a significantly lower degree of swelling in electrolyte aqueous solutions than in water, and also suffer from the so-called fading phenomenon in which the degree of swelling decreases when immersed in water for a long period of time. It has its drawbacks.

On the other hand, in order to solve these drawbacks, a water-stopping material using a nonionic water-swellable urethane resin has been proposed. For example, a water-swellable material made by blending water-swellable urethane resin with rubber and curing it (Japanese Patent Laid-Open No. 57-2:165
4, JP-A No. 57-119972), and a water-absorbing and water-retaining material made by blending a super absorbent resin and a water-swellable urethane prepolymer with a soft resin or rubber (JP-A-59-120653). etc. have been reported.

Can these methods yield water-swellable rubber-based water-stopping materials whose degree of swelling in an electrolyte aqueous solution is not much different from that in water?All of these methods use a water-swellable urethane prepolymer as a compounding component. This has the disadvantage that manufacturing is complicated. That is, first, it is necessary to synthesize a water-swellable urethane prepolymer, and a polyether polyol and a bifunctional organic diisocyanate are reacted to obtain a water-swellable urethane prepolymer containing terminal isocyanate groups. Next, the obtained water-swellable urethane prepolymer is mixed with rubber, and the mixture is further reacted with water or a curing agent such as a polyamine type or polyol type, thereby curing the mixture to obtain a water-stopping material. This process had the disadvantage of requiring a complicated process.

[Problem to be Solved by the Invention 8] The present invention has been made in order to improve such conventional drawbacks, and has a good swelling property in which the degree of swelling in an electrolyte aqueous solution is close to the degree of swelling in water. Another object of the present invention is to provide a water-swellable waterproof material that has excellent swelling stability and can be manufactured industrially advantageously, and a method for manufacturing the same.

[Means for Solving the Problems] As a result of various studies, the present inventors uniformly mixed an elastomer with a filler, a polyoxyalkylene glycol, and optionally a superabsorbent resin, and prepared a trifunctional diisocyanate and a trifunctional diisocyanate. By adding and reacting an isocyanate consisting of a polyisocyanate with a higher functionality, it is possible to perform a one-step reaction in a rubber compound without performing a two-step reaction as in the case of using a urethane prepolymer as in conventional examples. Forming a water-swellable polyurethane crosslinked product consisting of a reaction product of polyoxyalkylene glycol and isocyanate,
After that, by adding elastomer vulcanizing agents, vulcanization accelerators, etc., and molding and vulcanizing, water-swellable water-stopping materials with good swelling properties and excellent swelling stability can be produced industrially. The present invention has been completed based on the discovery that the present invention can be advantageously provided.

That is, the first invention of the present invention is an elastomer, a filler,
It is also characterized by being produced by vulcanizing a composition containing a reaction crosslinked product of a polyoxyalkylene glycol containing 50 to 90% by weight of oxyethylene units, a diisocyanate, and an isocyanate consisting of a trifunctional or higher-functionality polyisocyanate. It is a water-swellable waterproof material.

Further, the second invention is to uniformly mix an elastomer, a filler, and a polyoxyalkylene glycol containing 50 to 90% by weight of oxyethylene units, and then add an isocyanate consisting of a diisocyanate and a trifunctional or higher functional polyisocyanate to a polyoxyethylene glycol. NCO: 011 = 1.1: 1 to 2.5 to the hydroxyl group of alkylene glycol
: Production of a water-swellable water-stopping material characterized by adding an amount in the range of 1 and reacting to produce a crosslinked product consisting of the polyoxyalkylene glycol and isocyanate, and then vulcanizing the obtained composition. It consists of a method.

The present invention will be explained in detail below.

The basic structure of the water-swellable water-stopping material of the present invention is as follows.

Elastomers, fillers, and oxyethylene units 50
A product characterized by vulcanizing a composition containing a crosslinked product obtained by reacting a polyoxyalkylene glycol containing ~90% by weight with an isocyanate consisting of a diisocyanate and a trifunctional or higher functional polyisocyanate. It is.

Next, each of the above ingredients and their proportions will be explained.

The elastomer used in the present invention is natural rubber or synthetic rubber, and examples of synthetic rubber include polybutadiene rubber, styrene-butadiene copolymer rubber, nitrile-butadiene copolymer rubber, chloroprene rubber, and isobutylene-isoprene copolymer rubber. , ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, chlorinated polyethylene rubber, ethylene-vinyl acetate copolymer rubber, and the like. These natural rubbers or synthetic rubbers may be used alone or in combination of two or more.

The filler used in the present invention may be any filler that is commonly used in the elastomer,
Examples include carbon black, silica fillers, calcium carbonate, talc, clay, and titanium oxide. Among these, carbon black and silica fillers are mainly used. Furthermore, anti-aging agents, stabilizers, Machida agents, etc. can also be added as part of the filler.

The amount of filler added varies depending on the required characteristics of the water-swellable water-stopping material aimed at in the present invention, but is usually 100% of the elastomer.
40 to 150 parts by weight, preferably 50 to 150 parts by weight
120 parts by weight is desirable. If it is less than 40 parts by weight, the strength of the water-swellable water-stopping material will be insufficient, and if it exceeds tSO weight parts, the hardness of the water-swellable water-stopping material will become too high and its elongation will decrease, which is not preferable.

The polyoxyalkylene glycol used in the present invention is a polymer containing hydroxyl groups at both ends obtained by addition polymerization of alkylene oxide using ethylene glycol as a starting material by a conventional method. The polyoxyalkylene glycol has 50 to 90 oxyethylene units.
Examples of other oxyalkylene units whose content is preferably 60 to 80% by weight include oxypropylene and oxybutylene, and oxypropylene units are preferably used. If the oxyethylene unit content is less than 50% by weight, the degree of swelling of the resulting water-swellable waterproof material will be insufficient, and if it exceeds 90% by weight, the hardness of the water-swellable waterproof material will decrease over time due to crystallization of the oxyethylene units. It is not desirable because it increases.

The molecular weight of the polyoxyalkylene glycol used is
Usually 1000-6000 due to swelling degree and ease of handling.
Preferably, those in the range of 2000 to 5000 are suitably used.

The amount of polyoxyalkylene glycol to be used is preferably 40 to 150 parts by weight, preferably 50 to 130 parts by weight, based on 100 parts by weight of the elastomer.If it is less than 40 parts by weight, the degree of swelling of the resulting water-swellable waterproof material will be small; If the amount exceeds 150 parts by weight, the polyoxyalkylene glycol cannot be uniformly dispersed in the elastomer compound, which is not preferable.

In the present invention, isocyanates consisting of diisocyanates and trifunctional or higher functional polyisocyanates are used. Examples of this isocyanate include trifunctional or higher functional polyisocyanates, such as triphenylmethane triisocyanate, tris-(p-isocyanatephenyl)thiophosphite, polymethylene polyphenylisocyanate, etc., and diisocyanates, such as toluylene diisocyanate, naphthylene -1,5-diisocyanate, o-toluidine diisocyanate.

Combination use with diphenylmethane diisocyanate and the like can be mentioned. In addition, so-called crude MDI modified with diphenylmethane diisocyanate (containing about 50% by weight of diisocyanate and about 50% by weight of trifunctional or higher polyisocyanate, average NCO group = about 3) is also mentioned as an example of isocyanate.

The isocyanate used in the present invention includes:

Among the above, Crude MD is considered safe and easy to handle.
A combination of I or Crude 11101 and diphenylmethane diisocyanate can be particularly preferably used.

In the present invention, polyoxyalkylene glycol and isocyanate react to produce a crosslinked product (hereinafter referred to as a water-swellable crosslinked polyurethane product), and the production of the water-swellable crosslinked polyurethane product is performed in one step. It is carried out by reaction. The structure of the water-swellable crosslinked polyurethane consists of branching and crosslinking at trifunctional or higher functional polyisocyanate moieties.

In addition, the content of trifunctional or higher-functionality polyisocyanate in the isocyanate is preferably in the range of 20 to 50% by weight of the isocyanate; if it is less than 20% by weight, the degree of crosslinking of the resulting water-swellable polyurethane crosslinked product will be too low. Swelling stability decreases, and if it exceeds 50% by weight, the degree of crosslinking of the water-swellable polyurethane crosslinked product is too high, resulting in a decrease in swelling degree and a decrease in moldability, which is not preferable.

In addition, the amount of incyanate to be used is determined based on the required characteristics of the target water-swellable water-stopping material and the amount of incyanate added to the mixture during the urethane production reaction in which polyoxyalkylene glycol and incyanate react to produce a water-swellable polyurethane crosslinked product. NGO: 011=1.
1 + 1 to 2.5:1°, preferably 1.15:1
~2.0: Used within the range of l. 1.1
: If it is less than 1, the urethane production reaction will not proceed sufficiently,
Unreacted polyoxyalkylene glycol remains, causing an increase in eluted content, and when it exceeds 2.5.1, the allophanate reaction due to excess polyisocyanate increases, resulting in a high degree of crosslinking of the water-swellable polyurethane crosslinked product. This is undesirable because it causes a decrease in the degree of swelling and a decrease in moldability.

The urethane production reaction can also be carried out by adding a commonly used urethane production catalyst. Examples of urethane forming catalysts include tin chloride, dibutyltin dilaurate, dibutyltin maleate, and the like.

In the present invention, the superabsorbent resin can be used for the purpose of increasing the degree of swelling of the water-swellable water-stopping material. As a super absorbent resin, the water absorption capacity for water is 300 to 800.
You can use twice as many. Examples of such superabsorbent resins include commercially available starch, polyacrylate-based superabsorbent resins, crosslinked polyacrylates, and vinyl alcohol-based superabsorbent resins.
Examples include crosslinked products of copolymers of acrylic acid salts, crosslinked products of maleic anhydride/isobutylene copolymers, and the like. Among these, from the viewpoint of durability, superabsorbent resins obtained by crosslinking copolymers containing carboxyl groups or α,β-unsaturated compounds that can be converted into carboxyl groups as monomer components are preferably used. It will be done. The superabsorbent resin is preferably used in an amount of 0 to 100 parts by weight per 100 parts by weight of the elastomer.

In the present invention, when vulcanizing a composition containing an elastomer, a filler, and a water-swellable polyurethane crosslinked product, an elastomer vulcanizing agent, a vulcanization accelerator, etc. can be used. As the vulcanizing agent, vulcanizing accelerator, etc., it is sufficient to use a combination of vulcanizing agent, vulcanizing accelerator, etc. that is compatible with the elastomer used. For example, sulfur, sulfur compounds, or zinc oxide,
Vulcanizing agents such as metal oxides such as magnesium oxide and litharge, and guanidine-based, sulfenamide-based, thiuram-based,
A vulcanization accelerator such as a thiazole type or a dithiocarbamate type can be used in combination. Organic peroxides can also be used as vulcanizing agents, but in this case no vulcanization accelerator is required. Examples of organic peroxides include dicumyl peroxide, 1,1-bis(t -butylperoxy) 3. :l,5-trimethylcyclohexane, lobutyl-4,4'-bis(1-butylperoxy)valerate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and the like. The amounts of the vulcanizing agent, vulcanization accelerator, etc. used may be the amounts generally used for vulcanization of ordinary elastomers.

The water-swellable water-stopping material of the present invention can be produced by mixing, reacting, and vulcanizing the various ingredients described above, or if the equipment used for the mixing and reaction is capable of mixing, heating, and cooling. Good examples include internal mixers such as roll or Banbury mixers, kneader 1 pressure kneaders, and the like. Among these, a pressure kneader is most preferably used in terms of safety and reaction stability.

Vulcanization can be carried out by any conventional method without particular limitation, such as hot pressure vulcanization, hot air vulcanization, etc.

To show a specific example of the method for manufacturing the water-swellable water-stopping material of the present invention, first, an elastomer is placed in the device and masticated, and then a filler and a polyoxyalkylene glycol,
If desired, add a super absorbent resin and mix uniformly.Next, after adding a urethane forming catalyst if necessary, add isocyanate consisting of diisocyanate and trifunctional or higher polyisocyanate, and heat at 60 to 120°C. The reaction was carried out at a temperature of 1 to 30 minutes, and water consisting of a reaction product of polyoxyalkylene glycol and isocyanate was dissolved.
! i1? A water-swellable waterproof material can be obtained by forming a cross-linked polyurethane, then adding a substantial amount of an elastomer vulcanizing agent and a vulcanization accelerator, followed by molding and vulcanization.

[Function] The present invention involves uniformly dispersing polyoxyalkylene glycol in a so-called elastomer compound, which is made by uniformly mixing an elastomer, filler, polyoxyalkylene glycol, and optionally a superabsorbent resin, and then dispersing the polyoxyalkylene glycol into a diisocyanate. By adding and reacting an isocyanate consisting of a trifunctional or higher functional polyisocyanate, a water-swellable polyurethane crosslinked product consisting of a reaction product of polyoxyalkylene glycol and an isocyanate is produced in a single reaction in an elastomer compound. Can be done.

The elastomer compound uniformly containing the water-swellable crosslinked polyurethane is vulcanized by adding a vulcanizing agent and a vulcanization accelerator, so that the elastomer crosslinked product and the water-swellable crosslinked polyurethane become entangled with each other. structure, location, ]IPN(
Interpenetrating Polymer Network: InterpenetraLingPolymer
It is believed that a water-swellable water-stopping material with excellent swelling stability and excellent swelling stability can be obtained.

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

The swelling ratio is determined by cutting a 20 x 20 square sample piece from a press-molded or extruded vulcanized product, immersing it in tap water or various electrolyte aqueous solutions at 23°C for 7 days, then measuring the weight. It was calculated using the formula.

Moreover, the extracted content was determined by the following formula by immersing the sample in tap water at 23°C for 14 days, then drying it for 1 day at 105°C using a gear oven, and then measuring the weight.

Example 1 20I with the formulation shown in Table-1! Mixing and reaction were carried out using a pressure kneader (manufactured by Hode Seisakusho, Model D2G-40). First, after stranding natural rubber for 5 minutes, filler and poly(oxyethylene-oxypropylene) glycol [obtained by addition polymerizing ethylene oxide and propylene oxide to ethylene glycol in a weight ratio of 90:10 by a conventional method. A random copolymer containing hydroxyl groups at both ends, molecular weight 3000.0H groups=2] was added and mixed uniformly.

After adding stannous chloride as a urethane production catalyst, a polyisocyanate mixture (crude MDI, trade name MDI
-CR-200, average NCO group = approximately 3, manufactured by Mitsui Toatsu ■)
was added and stirred for 15 minutes at a temperature of 80°C to obtain a reaction mixture. Add vulcanizing agent to the resulting reaction mixture using a roll;
A vulcanization accelerator was added and press vulcanization was carried out at 160°C for 20 minutes to obtain a sheet with a thickness of 2 mm. Table 2 shows the physical properties and W wetness ratio of the obtained vulcanized sheet.

1) Magnesium oxide: Kyowa Mag 100 (Kyowa Chemical Industry type) 2) Anti-aging agent: Naragat 445 (manufactured by Uniroyal) 3) Carbon black: Geast SO (manufactured by Tokai Carbon) 4) Wet silica: Nip Seal VN-: l (Japan) Silicic acid)5)
Medium: Stannous chloride (manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.) 6) Polyisocyanate mixture: Crude MDI, trade name MDI・CR-200 = Zinc White No. 1 (manufactured by Seisei Kagaku Co., Ltd.) 8) Vulcanization accelerator CZ Nick Cellar CZ ( (manufactured by Shinko Ohmukai) Example 2.3 The weight ratio of the oxyethylene units and oxypropylene units of the poly(oxyethylene-oxypropylene) glycol used in Example 1 was 75:25 (molecular weight approximately 3
000) and 50:50 (molecular weight approximately 3000), a reaction product was obtained in the same manner as in Example 1, and then press-molded to obtain a vulcanized sheet with a thickness of 2 mm. . Table 2 shows the physical properties and swelling ratio of the obtained sheet.

Comparative Example 1 Polyethylene glycol # was used instead of poly(oxyethylene-oxypropylene) glycol used in Example 1.
A reaction product was obtained in the same manner as in Example 1 using 8 parts of MDI 6000 (molecular weight 6000, Toho Kagaku type) and crude MDI, and then press molded to obtain a press sheet with a thickness of 2. The physical properties and swelling ratio of the obtained sheet are shown in Table 2, but the hardness was too high to withstand practical use.

Comparative Example 2 A reaction product was obtained in the same manner as in Example 1 using poly(oxyethylene-oxypropylene) glycol with a weight ratio of oxyethylene units and oxypropylene units of 40:60 (molecular weight approximately 3000). After that, it was press-molded to obtain a press sheet with a thickness of 2mm. The physical properties and swelling ratio of the obtained sheet are shown in Table 2.The swelling ratio was too small to be put to practical use.

Examples 4 to 6 and Comparative Example 3.4 Example 1 using chloroprene rubber with the formulation shown in Table 3
A reaction product was obtained by carrying out the same operation as above, and then press-molded to obtain a vulcanized sheet having a thickness of 2 cm. Table 4 shows the physical properties and 11 wet ratio of the obtained sheet.

1) Chloroprene rubber: Denka Chloroprecito-40° (manufactured by Denki Kagaku Kogyo Co., Ltd.) 2) Poly(oxyethylene-oxypropylene) glycol: ethylene glycol with ethylene oxide and propylene oxide randomly added to both ends by a conventional method Hydroxyl group-containing polymer.

Oxyethylene unit 75% by weight 1 molecular weight approx. 3000 c) Vulcanization accelerator TT Nickceller TT (manufactured by Ohmukai Shinko) Bot (oxyethylene-oxypropylene) glycol added in an amount less than 40 parts by weight per 100 parts by weight of the elastomer. The degree of swelling was so small that it could not be used. If the amount exceeds 150 parts by weight, the poly(oxyethylene-oxypropylene) glycol cannot be uniformly dispersed in the elastomer compound, and an abnormal urethane production reaction occurs, making it impossible to obtain a molded article.

Examples 7 to 10 The same operations as in Example 1 were performed using the formulations shown in Table 5 to obtain reaction products. After adding a vulcanizing agent and a vulcanization accelerator to the obtained reaction product using a roll, a tape-shaped extrudate with a cross section of 3×20 squares was obtained using a rubber extruder with a screw diameter of 50 mm. The resulting extrudate was heated in a gear oven at 150°C for 3
Vulcanization was performed by heating for 0 minutes. Table 7 shows the surface condition, physical properties, degree of swelling, and extractable content of the obtained vulcanized tape.

Comparative Example 5 Terminated hydroxyl compound prepared by randomly copolymerizing glycerin with ethylene oxide and propylene oxide, (1 minute j'-
13,000 polyoxyethylene-oxif.

Synthesized ropyrene triol. A urethane prepolymer containing terminal isocyanate groups was obtained by reacting 3 moles of tolylene diisocyanate per mole of this triol in a conventional manner. The resulting urethane prepolymer was mixed with the chloroprene rubber, filler, and urethane prepolymer in a 3C pressure kneader according to the formulation shown in Table 6, and then a liquid curing agent containing 40% methylenebisorthochloroaniline was added. The reaction was then carried out at 100°C for 30 minutes.

After adding a vulcanizing agent and a vulcanization accelerator to the obtained reaction product using a roll, a tape-shaped extrudate having a cross section of 3×20 mm was obtained using an extruder. Then, in a gear oven at 150℃ for 3
Vulcanization was performed by heating for 0 minutes. The surface condition, physical properties, swelling ratio, and extractable content of the obtained vulcanized tape are shown in Table 7, but the surface condition of the tape was poor and could not be put to practical use.

1) W-1000: Plasticizer Product name Polycysate 1000 (manufactured by Dainippon Ink) 2) Sumikagel: Super water absorbent resin Sumikagel SP-520 (manufactured by Sumitomo Chemical) 3) Poly(oxyethylene-oxypropylene) glycol: Example 4 ~ Same as 6 4) MDI LT Nidiphenylmethane diisocyanate liquid amount, Neo
Group = 2 (manufactured by Mitsui Toatsu) 5) Perhexa 3M: 1. l-bis(t-butylperoxy)3,:I,5
-Trimethylcyclohexane (manufactured by NOF) Table 6 (parts by weight) [Effects of the invention] As explained above, the water-swellable water-stopping material of the present invention exhibits excellent water rJj1g4 properties, and also has a high degree of swelling with respect to an electrolyte aqueous solution. It exhibits good swelling properties close to that of water, and has excellent swelling stability and mechanical strength, making it an extremely useful water-stopping material.

In addition, conventional water-stopping materials containing water-swellable polyurethane-containing elastomer compositions first synthesize a water-swellable urethane prepolymer, then mix the water-swellable urethane prepolymer with an elastomer, and then add a curing agent.・Is a complicated process of reacting to form a water-swellable polyurethane crosslinked product necessary?According to the present invention, without synthesizing a water-swellable urethane prepolymer, water [11 It becomes possible to form a polyurethane crosslinked product, and it becomes possible to industrially advantageously produce a water-swellable water-stopping material very easily.

The water-swellable water-stopping material of the present invention thus obtained can be suitably used for segment sealing materials, rubber tube rubber rings, packings, separators, waterstop plates, and the like.

Agent: Hiroshi Watari Hebe

Claims (2)

[Claims] (1) Vulcanize a composition containing an elastomer, a filler, and a reaction crosslinked product of a polyoxyalkylene glycol containing 50 to 90% by weight of oxyethylene units and an isocyanate consisting of a diisocyanate and a trifunctional or higher functional polyisocyanate. A water-swellable water-stopping material characterized by: (2) After uniformly mixing the elastomer, filler, and polyoxyalkylene glycol containing 50 to 90% by weight of oxyethylene units, an isocyanate consisting of diisocyanate and trifunctional or higher functional polyisocyanate is added to the hydroxyl groups of the polyoxyalkylene glycol. Against NC
O:OH is added in an amount in the range of 1.1:1 to 2.5:1 and reacted to produce a crosslinked product consisting of the polyoxyalkylene glycol and isocyanate, and then the resulting composition is vulcanized. A method for producing a water-swellable water-stopping material, characterized in that: