JPH03281591A - Water-expandable one-pack type polyurethane sealing material composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent dilating speed and ratio with water and adhesivity and applicability to the treating object and useful as various water-stopping materials, toys, etc., by compounding a small amount of a highly water-absorbing resin as an essential component to a main material composed of a polyurethane prepolymer, etc. CONSTITUTION:The objective composition is produced by compounding (A) a highly water-absorbing resin reactive with the terminal isocyanate group of urethane as an essential component to a composition composed of (B) a water-expandable main material composed of a polyurethane prepolymer having isocyanate group at the terminals and (C) a filler, a plasticizer, a thixotropic agent, a solvent and other assistants. The weight ratio of A:B is preferably about 99:1 to 50:50.

Description

[Detailed description of the invention] [Purpose of the invention]

[Industrial Field of Application] The present invention relates to a water-swellable one-component polyurethane sealant composition useful as a sealant, and more specifically,
Water-stopping materials for buildings, various machinery, electric wires, cables, etc., tunnel segment sealing materials, weather strips, aluminum sashes, etc., water-stopping materials for humid pipes, water-stopping materials for collared propulsion pipes, toys, etc. The present invention relates to a useful water-swellable one-component polyurethane sealant composition. [Prior Art] Conventionally, water-swellable sealants include (1) rubber or synthetic resin kneaded with a highly water-absorbent resin, and (2) liquid-type polyurethane sealants. However, both of these have the disadvantage that it takes time to stop water because the rate of expansion by water is slow. In addition, (2) is a string-like material that has been extruded in advance at the factory and is bonded to the segments at the construction site, so it often peels off due to poor adhesion, peeling due to operational errors when assembling the segments, and sometimes there is water in the corners when gluing. Shallow water may occur due to peeling of the segment, poor fit to the segment, or poor fit to small irregularities, and a large amount of cost is required for rework.
is superior in terms of workability because it can be constructed on-site, but non-expandable types do not have the ability to follow changes in the ground, causing shallow water. Therefore, recently water-swellable rheological sealants have become popular, but the water expansion speed and li
j Because the tension is low, it takes time to stop water, and the stopping accuracy is not sufficient. (Problem to be Solved by the Invention) Therefore, the problem to be solved by the present inventor is to provide a water-swellable one-component type that has excellent water expansion speed and coefficient of expansion, as well as excellent adhesion to objects and workability. The object of the present invention is to provide a polyurethane sealant composition that overcomes the drawbacks of known one-component polyurethane sealants. [Means for Solving the Problems] (Summary) In order to solve the above problems, the water-swellable one-component polyurethane sealant composition according to the present invention consists of a polyurethane prepolymer having isocyanate groups at the terminals. The composition consisting of a main material, a filler, a plasticizer, a thixotropic agent, a solvent, and other auxiliary agents is characterized in that it contains a small amount of a superabsorbent resin as an essential component. Below, important matters regarding the present invention will be explained in detail. (a) Urethane prepolymer containing terminal isocyanate groups The urethane prepolymer containing terminal isocyanate groups in the composition of the present invention is produced by reacting isocyanate and polyol by a known method. The isocyanate group content is preferably 0.5 to 5% by weight, particularly preferably 1 to 2% by weight. The polymerized product (cured product) of the above prepolymer can become hydrophilic or hydrophobic depending on the type and blending ratio of raw materials, but for the purpose of the present invention, it is preferable to make it hydrophilic, especially water-swellable. Prepolymers that give polymers are desirable. However, even a prepolymer that provides a non-expandable polymer can be used alone or in combination with a prepolymer that provides expansibility. Examples of the isocyanate used in the production of the prepolymer include 2.4-)-lylene diisocyanate, 2.
6-) lylene diisocyanate and mixtures thereof, crude tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4''-diphenylmethane diisocyanate and mixtures of both, polymethylene polyphenyl polyisocyanate (crude diphenylmethane diisocyanate), xylene diisocyanate, These include hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexahydroxylylene diisocyanate, and carbodiimide modified products, dimers, trimers, etc. of these polyisocyanates.The polyols used for producing the prepolymer include, for example,
Polyether obtained by addition polymerizing one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc. to polyhydric alcohols such as water, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, and pentaerythritol. It is a polyol. In addition to the above, polyester polyols obtained by reacting polycarboxylic acids with low molecular weight polyols, polyester polyols obtained by polymerizing caprolactone, and OH group-containing higher fatty acid esters such as castor oil can also be used. Furthermore, a polymer polyol obtained by graft polymerizing an ethylenically unsaturated compound such as acrylonitrile, styrene, or methyl methacrylate to the above-mentioned known polyether polyol or polyester polyol;
Alternatively, 1,4-polybutadiene polyol or hydrogenated products thereof can also be used. If necessary, a low-molecular polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, hexanetriol, etc. may be mixed with the polyol. It can also be used as (b) Filler The filler used in the composition of the present invention is preferably, for example, calcium carbonate, talc, kaolin, zeolite, diatomaceous earth, or the like. Note that the lower the moisture content of these fillers, the better, and preferably 0.1% by weight or less. (c) Plasticizers and thixotropic agents Examples of the plasticizers used in the composition of the present invention include dioctyl butarate (DOP) and dibutyl phthalate (DBP).
＞, dibutyl phthalate (DLP), butyl pentyl phthalate (BBP), dioctyl adipate (DO
A), diisodecyl adipate (DIDA),) lyoctyl phosphate (TOP), chlorinated paraffin, etc.
These are preferably added in an amount of 1 to 40% by weight in the composition. Examples of the thixotropic agent used in the present invention include ultrafine silica, aluminum stearate, and surface-treated bentonite, and these are preferably added in an amount of 1 to 5% by weight in the composition. (d) Solvents Examples of solvents that may be blended into the composition of the present invention include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane, heptane, and octane; and various solvents ranging from gasoline to soluble oil fractions. petroleum solvents; esters such as ethyl acetate and butyl acetate; ketones such as ascent, methyl ethyl ketone, and methyl isopropyl ketone; and ether esters such as cellosolve acetate and butyl cellosolve acetate. It is added in a range of 20% by weight. (e) Other auxiliaries The composition of the present invention may contain stabilizers and colorants such as carbon black and titanium oxide as other known auxiliaries. (f) Super absorbent resin The super absorbent resin that is an essential component of the composition of the present invention can be produced, for example, by polymerizing a monomer containing a carboxylic acid group in the presence of an alkali, according to a known method. For example, saponification of crosslinked polyacrylates having carboxylic acid residues in the molecule, starch/acrylic acid (salt) copolymers, modified isobutylene/maleic acid copolymers, and vinyl acetate/acrylic acid ester copolymers. Examples include cross-linked sulfonic acid group-containing polyacrylates,
Of course, it is not limited to these. In addition, it is preferable that the carboxylic acid residue (including the -part hydroxyl group) of the superabsorbent resin is contained in a free form, even if only partially. This is because reacting with the terminal isocyanate groups of polyurethane is effective in preventing the superabsorbent resin from being detached when the polyurethane sealant expands with water. The superabsorbent resin used in the present invention preferably has a high water absorption of 20 g or more, preferably 100 g or more per 1 g of water absorption, and if necessary, two or more of the resins may be mixed and used. You can also do that. (g) The preferred blending ratio (weight ratio) of the terminal isocyanate group-containing urethane prepolymer (A) and the super absorbent resin (B), which is greater than the blending ratio, varies within a considerable range depending on the application. In general,
It is preferable that A:B=99:1 to 50.50. In addition, fillers, plasticizers, thixotropic agents, solvents and other auxiliary agents,
It is not possible to outline a suitable quantitative range here, since the nature of the ingredients must be blended depending on the intended use. (H) Usage form The composition of the present invention is preferably in the form of a paste-like amorphous composition, and is filled into a gap in an object using a known press-fitting means such as a hand gun. However, if desired, it can be shaped into a plate, rod, or other arbitrary shape and used for the various sealing purposes described above. [-Function] Provided by the present invention--Liquid type liquid 1. - In the Tashi sealing material composition, the terminal isocyanate groups containing 4 and 1+ form a network of urethane bonds due to moisture in the atmosphere. The superabsorbent resin, which is an essential component of the present invention, enters the workpiece, absorbs water and expands by itself, and expands the network and increases the volume of the entire cured composition. Improved contact with the inner wall and markedly improved water performance.
In particular, when the water-absorbing resin has reactive residues, the isocyanate groups of the resin react 1.5 and the resin is prevented from being desorbed. is maintained, and environmental pollution due to desorption is also prevented.
Although examples are given in detail, each example is merely for explanation and does not imply any limitation or restriction on the idea of the invention. (Left below) Examples 1 and 7 1. The composition shown in Table 1 was stirred and mixed in a homomixer according to a known method, and then passed through three ink rolls.
The compositions were obtained by defoaming 8. The blending amounts in the table are parts by weight. Table-1 Note) Book, manufactured by Dainippon Ink Industries, Ltd. (Pandex T
P-654>N2(A) 8 pieces Catalyst Kagaku T￥■ Manufactured by 7ri7rick C8-78>(B) ■ Kurashi <Kl Gel
201-F2) (C) Sumitomo Chemical Co., Ltd. (manufactured by 11 (λ Miki Gel 5P-520) (A') 11 Catalyst Chemical Industry @ Manufactured Aqualic C5-7S) was neutralized with caustic soda 7, and carvone Adjust acid soda sensitivity to 100% (B゛) ■Kura1/manufactured (Kl Gel 201-F2>
Using caustic saw, neutralize with sodium carboxylate and add 1 to 10
Adjusted to 1"l %, Takehara Chemical Co., Ltd. (Ne4 Uji 5P-T), Degusaji, Yaban Ltd. (Air 1 Lulu R-972) Test Example Next, the compositions in Table 1 were tested under the same conditions. So cast 1, temperature 2
A test piece was obtained after curing for 3 days in an atmosphere of 0°C and 60% humidity. Swelling rate and elution 1 in tap water for the above 7 test pieces
was observed and the results shown in Table 2 below were obtained. (See margin below) Evaluation of elution amount after surface water absorption After immersion in tap water for 7 days, dry the sample at 105°C for 48 hours and overlay measurement Evaluation: Elution amount 0.5% or less F, ◎, 1% or more 0.1.5% or less of 1τ is indicated as △6 Separately, a water stop test was conducted using a disc type tester according to the following test method, and the results shown in Table 3 below were obtained. (Test method) As shown in Figures 1 and 2, two metal disks (flanges) placed vertically opposite each other are placed in a concentric circle at 2°2° and the middle lower disk 2°. An annular group 3 with a depth of 2 mm and a width of 20 mm was carved in the lower disk 2' using a testing machine 1 equipped with a pressure gauge 4 and a vibro connected to a pump 5 on the upper disk 2. Make sure that the groove is flush with the disk surface.
The compositions S of Examples 1 to 7 were respectively injected, and after curing at room temperature for 3 days, a spacer 7 with a thickness of 0.4 mm was interposed between both plates, and bolts and nuts 8, 8, etc. were tightened. , observe the shallow water condition after 6 hours, 12 hours, 1 day, 2 days, 3 days, and 7 days under a predetermined water pressure. (Leaving space below) Table note 1) The symbol “〉” in the table indicates that the period required for water stoppage is longer than the indicated period, and the symbol “ku” indicates that the period is within the indicated period (e.g. : "6 hours" indicates that the water stopped within 6 hours.) As shown in the test results in Tables 2 and 3 above, the sealing material according to the present invention has excellent water-stopping performance and a small amount of elution.

【Effect of the invention】

As explained above, the present invention provides a novel sealing material that has an epoch-makingly high water-stopping speed and has long-term water-stopping performance, and has been applied to civil engineering works, various machinery, electric cables, tunnels, etc. It can contribute to the rationalization of water stoppage work in a wide range of fields, such as sealing materials for humid pipes.

[Brief Description of the Drawings] Fig. 1 is an overall perspective view of the paper device used for performance testing of the sealing material of the present invention, and Fig. 2 is a partial enlarged sectional view of the main parts. are as follows: 1: entire test apparatus; 2: upper disc, 2″: lower disc, 3: 2° annular group 4: pressure gauge, 5: pump, 6: piping, 7 ;spacer,
8: Bolt/Nut; S: Test composition.

Claims (1)

[Scope of Claims] 1. A composition consisting of a main material consisting of a polyurethane prepolymer having an isocyanate group at the end, and fillers, plasticizers, thixotropic agents, solvents and other auxiliary agents, with a small amount of essential components. A water-swellable one-component polyurethane sealant composition comprising a super absorbent resin. 2. The sealant composition according to claim 1, wherein the polyurethane prepolymer having an isocyanate group at its terminal is water-swellable. 3. The sealing material composition according to claim 1, wherein the super absorbent resin is reactive with the terminal isocyanate group of urethane.