JPS58160386A - Polyurethane-based sealant - Google Patents

Abstract

PURPOSE:To provide a polyurethane-based sealant containing polyurethane resin, highly water-absorbing polymer and bentonite as essential ingredients, exhibiting excellent water checking and swelling property, resistance to water and durability and useful for checking water between segments in tunnel consturction work, etc. CONSTITUTION:The sealant contains, as essential ingrediens, 100pts.wt. polyurethane resin (a), 1-100pts.wt. highly water absorbing polymer (b) and 10-300pts. wt. bentonite (c). Polymer (b) is obtained by physically or chemically crosslinking a high-molecular electrolyte and it absorbs water to swell by several hundreds times its own weight at normal temperature or under heating but does not dissolve in water. When it has absorbed water, it retains elasticity in shape. Examples are starch/sodium acrylate graft copolymer and saponified vinyl ester/ethylenically unsatd. carboxylic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyurethane sealing material having excellent water-stopping properties and f'E properties.

Conventionally, polyurethane sealants have been widely used in civil engineering and construction applications due to their excellent elasticity, water resistance, and durability. However, even when such a polyurethane sealing material is used, it has been expected that it will completely stop leakage of rainwater and the like after many years of use.

For example, when applying polyurethane sealants, in order to prevent them from peeling off from the surface to which they are adhered due to shrinkage in cold weather, studies are underway to develop primers with good adhesive properties, but so far no primer has been found that is completely satisfactory. It's a difficult situation to be in.

In view of these circumstances, the present inventors conducted intensive research and found that by incorporating polyurethane resin, super absorbent polymer, and bentonite as components of the polyurethane sealant, water leakage prevention performance can be maintained over a long period of time when the cotton is opened. We have discovered what is possible and completed the present invention.

Even if the polyurethane sealant according to the present invention peels off from the surface to which it is adhered, it absorbs water and swells in a short period of time when rainwater etc. enters, blocking the voids created by the peeling, so that rainwater etc. cannot infiltrate. can be prevented. That is, in the present invention, the polyurethane sealing material contains a polyurethane resin and 700 parts of the polyurethane resin, a super absorbent polymer of /~/θθ parts, and bentonites in a ratio of 70 to 390 parts. It is something to do.

The superabsorbent polymer and bentonite used in the present invention are preferably in the form of fine powder, and preferably have a particle size of 7 to /θθμ.

The feature of the present invention is that it is a polyurethane sealing material that enables the swelling of superabsorbent polymers in a short period of time by blending hydrophilic bentonites into polyurethane resin, and that causes less deterioration in physical properties.

In addition, in the case of a sealant made only of polyurethane resin and a superabsorbent polymer, the superabsorbent polymer is undone by the polyurethane, so contact with water is not bad, and the amount of superabsorbent polymer is actually small. It is very inefficient.

On the other hand, according to the method of using bentonite of the present invention,
Because of its hygroscopicity, it easily draws moisture into the vicinity of the superabsorbent polymer, and is extremely effective in causing the superabsorbent polymer to swell in a short time.

The polyurethane resin used in the present invention can be obtained by a known reaction between polyisocyanate, polyol, polyamine, water, and the like. The polyurethane resin used in the present invention is preferably a polymer generally used as a sealing material, and may be of a one-pot type or a prepolymer type. If necessary, commonly used polyurethane additives such as tar, asphalt,
It may also contain animal and vegetable oils and fats, DOP, and mineral oils.

Furthermore, the superabsorbent polymer used in the present invention is one in which a polymer electrolyte is physically or chemically crosslinked.
It is a substance that absorbs water and swells to several hundred times its own weight at room temperature or in a heated state, but is difficult to dissolve in water and can maintain an elastic shape even when it absorbs water. For example, starch/sodium acrylate graft copolymers, salts of styrene-maleic anhydride copolymers, crosslinked products of sodium polyacrylate and polyvinyl alcohol/maleic anhydride copolymers, vinyl esters/ethylenically unsaturated carboxylic acids, or Known super absorbent polymers such as saponified derivatives thereof can be mentioned. Among them,
Crosslinked products of sodium polyacrylate and saponified products of copolymers of vinyl ester and acrylic ester have high water absorption capacity and excellent strength after water absorption, so it is desirable to use them.

The bentonites used in the present invention are mainly composed of montmorillonite and contain quartz, feldspar, and calcite, and the main components are 5j02 and 4203.
It has the property of absorbing water and swelling.

The method for manufacturing the polyurethane sealant according to the present invention is carried out according to a conventional method. That is, A component self, fist, -
Ureta: Noprepolymer, component B: polyol compound, super absorbent polymer, and bentonite a,
It is a composition in which fillers, catalysts, stabilizers, colorants, and other additives are mixed and dispersed using a triple roll or the like, if necessary. Oh,
Component A and component B are thoroughly mixed and used at the time of construction according to a normal method.

Furthermore, when the urethane sealant of the present invention is used, it does not matter whether it is used in a fixed shape or an irregular shape. That is,
If the cross-sectional dimensions of the filling area (joint) are approximately constant, the composition of the present invention may be cured and molded, cut into a shape, and then pushed into the filling area to prevent water leakage. If the cross-sectional dimensions of the filler are not constant, the composition of the present invention may be filled into the filling location and cured and swelled there to prevent water leakage.

The urethane sealing material of the present invention is useful, for example, for stopping water between segments in tunnel construction, stopping water at humid pipe connections, stopping water between gaps between outer wall panels of buildings, and as a backing for preventing water leakage.

The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to these. All parts in the examples are by weight.

Test method The water leakage test of the present invention was actually confirmed using segment waterproofing. Segment waterproofing test involves assembling segments, filling the joints of the segments with sealant, and using a barrel to judge if water leakage is detected, and if water is stopped, water is stopped.

Moreover, the swelling ratio referred to here indicates the weight increase after the cured product is immersed in tap water for S days.

Example: 1 mole of a triol with an average molecular weight of 3θθθ obtained by adding propylene oxide to glycerin and 3 moles of toluene diisocyanate (TD any θ) are constantly added! ! A urethanebrae polymer containing terminal incyanate groups (UPX
-7) was produced.

[IPX −/: 75 parts of super absorbent polymer, Sumikagel S-Sθ (average particle size - θ part, Sumima Kagakuha product), 756 parts of bentonite, methylenebisorthochloroaniline (MOCtA) per iθθ part. Added 1.2s”
When the swelling ratio was measured by leaving it in the air at 30°C to completely cure it, it was 230%.

When a segment waterproof test was conducted on this product, it was found to be watertight.

For the UPI −/ /θθ part obtained in the implementation example/, super absorbent polymer, Sunwet E M -3θθ (average particle size Jθμ, Sanyo Chemical Products) 30 parts, Ventona 48290 parts, liquid hardening agent CAx -β (diol with average molecular weight/θθθ obtained by adding propylene oxide to propylene glycol) Ils part, 0.5 part of dibutyltin dilaurate as a catalyst was added, and 1. ! Released into the atmosphere at 3"C.

The swelling ratio was measured and found to be 795%. When a segment waterproof test was conducted on this product, it was found to be watertight.

Example 3 Super absorbent polymer Aqua Keep ZS (average particle size - θ part, steel manufacturing chemical industry product) rs part, bentonite / θ part, liquid hardening to UPX-/ /θθ part obtained in Example / Agent 0AX-j:! l! 1 part, 30 parts of tar, and 50 parts of calcium carbonate were added, and the mixture was left in the atmosphere at 1.25"C to completely cure. The swelling ratio was measured to be 23θ.

When a segment anti-IF test was conducted on this product, it was found to be IF water.

Example q 04.5 mol of a diol with an average molecular weight Jθθ obtained by adding propylene oxide to propylene glycol, 0.5 mol of a triol with an average molecular weight Ik3θθθ obtained by adding ethylene oxide to glycerin, and 03 mol of TD eny. Stir constantly and bring to 0°C.
A terminal incyanate group-containing urethane prepolymer (UPX-, 2) was produced by reacting with . U.P.
Sumikagel S-Sθ in X-, 2/θθ part, average particle size 4θ
70 parts μ (manufactured by Sumitomo Chemical Co., Ltd.), bentonite Jθθ part,
A liquid curing agent ahx-/knee θ part, 30 parts tar, and calcium carbonate/S part were added and left in the atmosphere at 1.2 J'C to completely cure.The swelling ratio was measured and was found to be 7 θ chi. . When a segment waterproof test was conducted on this product, it was found to be watertight.

Comparative Example/Example/UPX created in -/: /θθ part, Sumikagel S-Sθ, average particle size λθμ (manufactured by Sumima Kagaku Kogyo) 7
3 parts and 2 parts of Chx-i were added and left in the atmosphere at 1.25°C to completely cure.The swelling ratio was measured and found to be 7 parts%. When a segment waterproofing test was conducted on this product, water leakage was observed.

Comparative Example λ 756 parts of bentonite and 20 parts of CAM-/: were added to the UPX-,2/θθ part prepared in Example 1, and
When the dog meat of C was left inside and completely cured, the wetness rate was measured and it was 3. When we conducted a segment waterproof test on this product, water leakage was observed.

Claims (1)

[Claims] (1) A polyurethane sealing material characterized by containing a polyurethane resin, a superabsorbent polymer, and bentonite as essential components. (,2) The polyurethane sealing material according to claims/descriptions, wherein the core superabsorbent polymer is a polymer electrolyte containing a carboxylate.