JPS58108232A - Water-stopping material - Google Patents

Abstract

PURPOSE:To obtain a water-stopping material having improved water-stopping effect, by adding specific amounts of hydrogel and a hydrophilic additive to a foamed article, thereby increasing the permeation of water to the foamed article. CONSTITUTION:A foamed article (e.g. polyurethane resin) is incorporated with (A) 4-109wt% hydrogel, i.e. a water-insoluble water-absorbing resin powder (e.g. crosslinked sodium polyacrylate) and (B) 4-116wt% hydrophilic filler (e.g. starch, glass powder, etc.). The amount of the component (B) is >=1/10 of the component (A), and the sum of the components (A) and (B) is <=120wt%. It is preferable to foam the resin after the addition of the components (A) and (B).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a water-stopping material, particularly a water-stopping material made of a foam containing a water-insoluble water-absorbing resin (hereinafter referred to as "hydrogel") powder.

BACKGROUND ART Conventionally, it has been widely known to add hydrogel to produce a hydrophilic, water-absorbing foam when producing polyurethane.

The present inventors have previously developed a technique for utilizing these hydrophilic and water-absorbing foams as a stopper.

These stoppers have water-stopping properties that are much better than those made of foam having the same density, but as a result of further research, it was possible to further improve the water-stopping ability.

The water-stopping properties of foams containing hydrogels are due to the water retention and swelling power of the hydrogels, so maximum strength is exerted when all the hydrogels contained in the water-stopping material are evenly penetrated by water. . However, the water retention power of this hydrogel is very strong. For example, if the hydrogel is densely packed into a jcII width and water is applied to one side, the water will gradually travel through the hydrogel, but the permeation rate is about 2 cm / month. It is. Even when it is contained in a foam, the outer part that comes into contact with water first absorbs water and swells, and the water is transmitted to the inside, so the water stopping power that is theoretically possible does not actually work. Not demonstrated.

Usually, such a water-stopping material is used by providing an adhesive layer on one side and pasting it on the sealing surface, and then pressing it against the sealing surface on the opposite side to bring it into close contact. In this case, if the compressive hardness of the water stop material is low, water will pass through between the water stop material surface and the sealing surface even though the adhesive layer is provided.

In order to waterproof this water barrier, in order to maximize the water-stopping properties of the hydrogel-containing foam,
It is necessary to allow water to penetrate into the inside of the foam in a short period of time.

The object of the present invention is to provide a water stopper made of a hydrogel-containing foam that allows water to penetrate into the interior of the foam in a short period of time and has an improved water stopper effect.

As a result of research, the present inventors have found that when a hydrophilic additive is dispersed in a hydrogel-containing foam, water can penetrate into the foam along its surface. The present invention was completed based on this knowledge.

In order to impart water-stopping properties to the foam by including the hydrogel, it is preferable to mix the hydrogel in an amount of 109% to 109% by weight with respect to the foam, and the amount of the hydrophilic additive to be added is determined by the amount of the hydrogel relative to the foam. ~l16 % of the hydrogel, 17
10 or more, preferably i7s or more, and the total addition amount of the hydrogel and hydrophilic additive is 72 or more with respect to the foam.
It has been found that the content is preferably 0% by weight or less.

The foam in terms of weight % with respect to the foam refers to the foam itself excluding the hydrogel and hydrophilic additives contained in the foam.

When the amount of hydrophilic additive is less than 7770 times the amount of hydrogel, it cannot impart water permeability to the foam.

Furthermore, if the total amount of the hydrogel and the hydrophilic additive exceeds 120% by weight based on the foam, the strength of the foam will decrease significantly, so it should not be exceeded.

The foam in the present invention may be made of rubber or plastic. Examples include foamed materials such as polyacrylic resin, polyurethane resin, polyvinyl chloride resin, polyolefin resin such as polyethylene and polypropylene, natural rubber, synthetic rubber such as ethylene/propylene rubber, and chloroprene rubber. Among these, foams of polyvinyl chloride, ethylene/propylene rubber, chloroprene rubber, polyurethane resins, and especially polyurethane resins are preferred in terms of ease of production and stability.

Moreover, the foam is 0. It is preferable to have a tensile strength of jK9/c112 or higher for the purpose of application to a sealing surface. Also, the number of cells is 3.2n per 9 cells.
It is preferable that the cell number is less than 19.76 cells, the water-stopping property is low, and if it exceeds 19.76 cells, production becomes difficult.

Hydrogels include, for example, starch maku, which is made by graft polymerizing cellulose with acrylic monomers and its alkali metal salts, starch or cellulose graft polymerized with acrylonitrile and then hydrolyzed, and cross-linked products of sodium polyacrylate. , polyvinyl alcohol modified with maleic anhydride, saponified vinyl acetate/acrylic acid ester copolymer, and the like. However, the material is not limited to this, and any resin that can absorb water several tens of times its own weight or more may be used. Further, the particle size of these powders is preferably one that can pass through a 10-mesh sieve, and the finer the particle size, the better in terms of water quality.

A hydrophilic additive is one that does not contain divalent or higher ions as a main component and has a contact angle with water of to0 or less, preferably Vip0 or less. Broadly speaking, there are organic and inorganic types. Examples of organic hydrophilic additives include starch, polyvinyl alcohol, carboxymethyl cellulose, and the like. Examples of the inorganic hydrophilic additive include glass powder, glass fiber, white carbon, and silicic anhydride.

The hydrogel and the hydrophilic additive may be added to the foam by mixing them into the foam raw material and then infiltrating them, or by impregnating them after the foam is manufactured. The former method is preferred in order to obtain a uniform mixture.

The contact angle with water mentioned above refers to the shape of a droplet (Tsunefu Matsumoto).

Compatibility: Polymer chemistry, /7, ! 09 (/9JO
＞ ) refers to the value measured by

Example 1 A foam was manufactured using the following blending ratios. (Parts indicate parts by weight. The same applies hereinafter) KN-30! OK Mitsui Nissosha ill
100 parts Sumikagel A-u manufactured by Sumitomo Chemical Co., Ltd.
Part 30 Glasslon p-32! Asahi Finoku-Glass Co., Ltd. lS part F-//l
Manufactured by Shin-Etsu Chemical Co., Ltd. 1 part DABOOJJLV
Sankyo Airp Of? , Tsusha 1% [0.7 parts water

2.2 parts stack) T-9 manufactured by Yoshitomi Pharmaceutical Co., Ltd.
. , 7 parts TDI 6!731 manufactured by Nippon Polyurethane Co., Ltd. 31.6 parts The number of cells of the obtained foam is 3.2n/'9, and the air permeability is 0.3 ec/c+w
2. B@c, density 0. OA! ;f/cwt”
There was a time.

This foam is s cm x s cm X J cs
(Thick) K 9J When I floated it in a water tank, the initial weight was 36 x 32, but after 1 hour it weighed /
J, J It became 31.7 f after 9% 2 hours.

This foam has an inner diameter of B11φ, an outer diameter of 7381φ, and a thickness of θ
Cut this into n pieces9, compress it by 10% between two acrylic plates, one with a hole in the center for water to pass through, and pressurize at a rate of 0.2'9/C-min from the hole in the center of the acrylic plate. When water pressure was applied at 9, the water stop pressure was more than λ/ctn2.

Comparative Example A foam was manufactured using the following blending ratio: 1°. (The one without the hydrophilic additive used in Example 1)
OK 100 parts Sumikagel A-11730
# F-//da 1 part DABOO37LV O,
7#Water 2.2
＃Stacked knee 9 0J#TD
I 6373g J/, t #The number of cells of the obtained foam is 3. 7. per cod. s q, air permeability is 0, j cc/cm', 66c, density is 0.
It was 06097 cm.

When this foam was cut into the same size as in Example 1 and subjected to a water tank test, the initial weight was 3. After 7 hours, 1.
21f, 1 hour later/9. ! ? Met.

In addition, when the water stop pressure was tested in the same manner as in Example 1, the water stop pressure was 0.71C97 cm2. Example 2 A foam was manufactured using the blending ratio shown below.

100 parts Sumikagel A-Shun in KN-3030
30#p-//da
/,Q tDABCOJJ LV
O, 7 parts water
2.21 Stacked Ding-?
Q, 3yT D I ts/is
3. .

The number of cells of the obtained foam was 3. 7k pieces per con, jM
The air temperature was 1lt0.3cc/c*2-sec, and the density was 0.0t3f/CI++'te.

The foam was subjected to a water tank test and a water stop test in the same manner as in Example 1.

The initial weight was J, 1kF, but after 1 hour it was /K, 7f, and after 20 hours it was JJ, 2t. The water stop pressure is ky/c- or more.

As described above, the water-stopping material of the present invention has excellent water-stopping properties.

Patent applicant: NHK Spring Co., Ltd.

Claims (1)

[Claims] The foam contains ~109% by weight of water-insoluble water-absorbing resin powder (hereinafter referred to as hydrogel) and ~109% by weight of a hydrophilic additive.
iit% by weight, and the amount of hydrophilic additive added is 1/10 or more of the amount of hydrogel, and the total amount of hydrogel and hydrophilic additive is mixed in the foam such that the total amount of added hydrogel and hydrophilic additive is less than 1% by weight of the foam. A foam water stop material characterized by: