JP2592632B2 - Article sealing composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a composition for sealing a hole in a porous article such as a casting or a sintered metal article or a void at a joint of an assembly part. The present invention relates to a hermetically sealed composition in which the composition is prevented from escaping and water is prevented from entering, thereby improving the hermetic treatment effect.

[Conventional technology]

It may be necessary to seal the pores of the porous article or the voids at the joints of the assembled parts. This is necessary to withstand the pressure of liquid or gas when using the article, prevent water from entering, increase the density, increase the strength, prevent corrosion, etc. Necessary as a surface treatment for plating.

As this type of sealing composition, conventionally, a polymerizable acrylic acid compound, a thermosetting type mainly containing azobisnitrile as a polymerization initiator, or a polymerizable acrylic acid compound, as a polymerization initiator An anaerobic curing type mainly composed of an organic peroxide is known. The sealing treatment of a porous article is performed as follows using these compositions.
First, a porous article is placed in a tank, the inside of the tank is evacuated to remove air from the holes, and then the composition is poured into the tank, the porous article is immersed in the composition, and returned to normal pressure. This injects the composition into the pores of the porous article. Next, the porous article is taken out of the tank, and the excess composition adhering to the surface is washed and removed, and then immersed in warm water to cure the composition in the hole and complete the sealing.

[Problems to be solved by the invention]

However, in the above-mentioned method, the uncured composition in the pores is replaced by water and flows out in the washing step or the curing step in warm water. For this reason, especially in the case of a large hole, the sealing treatment becomes insufficient. This is the interfacial tension of water (60dy
n / cm) is higher than the interfacial tension (30-40 dyn / cm) of the polymerizable acrylic compound of the uncured composition, so that water is replaced with the composition in the pores and the uncured composition is This is because they are pushed out and flow out.

An object of the present invention is to form a hydrogel layer in the composition by reacting the water-absorbing polymer compound contained in the composition with water invading the pores or voids, and further forming a water-containing gel layer in the composition. Prevents intrusion and also prevents outflow due to replacement of the uncured composition with water, thereby improving the sealing effect,
It is an object of the present invention to provide a porous article or assembly sealing composition which ameliorates the disadvantages of the prior art.

[Means for solving the problem]

In order to achieve the above-mentioned object, according to the present invention, in a sealing composition containing a polymerizable acrylic compound and a polymerization initiator as main components, the polymerizable acrylic compound
It is characterized by further containing 0.1 to 3 parts by weight of a water-absorbing polymer compound per 100 parts by weight.

The aforementioned polymerizable acrylic compound is (R ₁ is H, halogen and lower alkyl having 1 to 4 carbon atoms)
And acrylic acid esters having a terminal group of, for example, hydroxyalkyl (meth) acrylate,
Glycidyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth)
Acrylate, propylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol entatri (meth) acrylate,
Tetramethylolmethanetetra (meth) acrylate,
Polyester (meth) acrylate obtained by reacting (meth) acrylic acid, glycols and polybasic acid, epoxy (meth) acrylate obtained by reacting epoxy compound with (meth) acrylic acid, polybasic acid and amino alcohol , Then amide (meth) acrylate obtained by reacting (meth) acrylic acid, urethane (meth) acrylate obtained by reacting hydroxyalkyl (meth) acrylate with a polyisocyanate compound,
Tetrahydrofurfuryl (meth) acrylate, (meth)
Dimethylaminoethyl acrylate, diethylaminoethyl (meth) acrylate, benzyl (meth) acrylate,
Examples include, but are not limited to, cyclohexyl (meth) acrylate.

The above-mentioned polymerization initiator is an azonitrile derivative or an organic peroxide. Azonitrile derivatives are compounds having the following general formula:

Where R ₁ is methyl, ethyl, n-propyl, iso-propyl, iso-butyl or n-pentyl, and R ₂ is methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, carboxy-n-propyl , Iso-butyl, cyclobutyl, n-pentyl, neo-pentyl, cyclopentyl, cyclohexyl, phenyl, benzyl,
P-chlorobenzyl or P-nitrobenzyl.
Typical examples and specific examples thereof include 2,2'-azobisiso-butyronitrile. Further, the amount is 0.05 to 1 with respect to 100 parts by weight of the polymerizable acrylic acid compound.
Parts by weight, preferably 0.1 to 0.3 parts by weight. Examples of the organic peroxide include diacyl peroxide, peroxyether, dialkyl peroxide, hydroperoxide, ketone peroxide, and the like.
Of these, particularly preferred organic peroxides are hydroperoxides or dialkyl peroxides, the amount of which is 0.1 to 10 parts by weight per 100 parts by weight of the polymerizable acrylic compound.
Parts by weight, preferably 0.1 to 2 parts by weight.

Further, specific examples of the above-mentioned water-absorbing polymer compound include starch-polyacrylonitrile graft copolymer starch-acrylate-based graft copolymer carboxymethylcellulose-based polymer cellulose-polyacrylonitrile-grafted copolymer polyacrylonitrile cross-linked Polymer Sodium polyacrylate Poly potassium acrylate Acrylic acid-vinyl alcohol copolymer Polyethylene oxide cross-linked polymer Polyvinyl alcohol-maleic ester copolymer Isobutylene-maleic anhydride copolymer Polyacrylate fiber methyl methacrylate Acid-vinyl acetate copolymer These modified products and the like, and as the trade name,
Aquaric CA (Nippon Shokubai Chemical Industry), Aquakeep (Steel Chemical Industry), Arasorp (Arakawa Chemical Industry), WAS
(Nissei Chemical), Sumikagel R, Sumikagel N (Sumitomo Chemical), Aqua Reserve (Nippon Synthetic Chemical Industry), KI gel (Kuraray, Kuraray Isoprene), Lanseal F (Nippon Xlan Industry), Aquaprene (Meisei Chemical), Gel Fine (Daicel Chemical Industries).

In addition, the compounding amount of the polymerizable acrylic compound 100
The amount is 0.1 to 3 parts by weight, preferably 0.5 to 1 part by weight, and if less than 0.1 part by weight, the sealing effect is not exhibited, and if it exceeds 3 parts by weight, the dispersion of the water-absorbing polymer compound is increased. It becomes insufficient and precipitates.

The composition of the present invention may further contain a polymerization inhibitor or a polymer compound in addition to the above-mentioned components. The polymerization inhibitor is, for example, a substituted phenol. Specifically, hydroquinone, hydroquinone monomethyl ether (MEHQ), catechol, tert-butyl catechol, p
-Benzoquinone, β-naphthoquinone, 2,6-di-tert
-Butyl-p-cresol, 2,5-di-tert-butylhydroquinone, picric acid, picric acid derivatives and the like, and particularly preferred examples are hydroquinone, hydroquinone monomethyl ether, and 2,6-di-
tert-butyl-p-cresol. This amount is any appropriate amount.

The above-mentioned polymer compound is a polymer compound soluble in the above-mentioned polymerizable acrylic acid compound, and examples thereof include acrylonitrile rubber, acrylic rubber, ethylene acrylic elastomer, urethane elastomer, vinyl butyral, and polyacrylate. In the present invention, the thixotropic property of the composition is more preferably imparted by containing the polymer compound as described later. The amount is such that the composition is in the range of 1 to 1000 cps, preferably 5 to 200 cps.

[Action]

The composition of the present invention contains a predetermined amount of a water-absorbing polymer compound, and reacts with water penetrating into pores or voids to form a hydrogel layer in the composition. And prevents the uncured composition from flowing out of the pores due to replacement with water, thereby improving the sealing effect.

〔Example〕

Example 1 As a polymerizable acrylic acid compound, 90 parts by weight of 2-hydroxyethyl methacrylate (trade name: GE-610, Mitsubishi Gas Chemical), 9.9 parts by weight of polyethylene glycol # 400 dimethacrylate (trade name: NK ester 14G, Shin-Nakamura Chemical) and polymerization were started. For a total of 100 parts by weight of a composition comprising 0.1 parts by weight of azobisisobutyronitrile as an agent (curing agent), a water-absorbing polymer compound (trade name Aqualic CS-7
Nippon Shokubai Kagaku) were added in the amounts shown in Table 1, and sample No.
6 was prepared. Each of these samples was subjected to a sealing treatment effect test by the following test method, and the results are shown in Table 1.

Test method As a test piece, it is an aluminum casting disc with a diameter of 80 mm and a thickness of 5 mm, and when an air pressure of ² kgf / cm ² is applied,
The air leakage rate is 300-500ml / min (test piece 1), 1300-1500ml / min (test piece 2) and 2000 respectively.
Three kinds of test pieces 1, 2 and 3 of 22500 ml / min (test piece 3) were used.

 The sealing treatment was performed by the following steps (A) to (D).

(A) Vacuum process Six test pieces 1, 2 and 3 are prepared respectively, each of them is placed in a separate container, and the degree of vacuum in the container is maintained at 5 mmHg for about 10 minutes. Remove air from inside.

(B) Impregnation Step The above-mentioned sample Nos. 1 to 6 were respectively injected into six containers each containing one test piece 1, and the test pieces 2 and 3 were similarly injected.
Each sample is impregnated into the hole of each test piece by applying a pressure of ² kgf / cm ² for 10 minutes.

(C) Water Washing Step After the impregnation step, each test piece is washed with running water for 3 minutes, and an extra sample attached to the surface is washed with water.

(D) Curing Step After the cleaning, each test piece is water-bathed in warm water at 90 ° C. for 10 minutes to cure the sample impregnated in the holes.

Table 1 shows that the samples Nos. 1 to 4 (compositions of the present invention) have excellent impregnation effects (sealing effect) over a wide range from the test piece 1 having a small hole to the test piece 3 having a large hole. This means that the composition of the present invention is prevented from flowing out of the pores in the washing step or the curing step in warm water regardless of the size of the pores.

If the amount of the water-absorbing polymer compound exceeds 3 parts by weight, the dispersion becomes insufficient and precipitation occurs. If the amount is less than 0.1 part by weight, the immersion effect is inferior.

Example 2 2-Hydroxyethyl methacrylate (trade name: GE-610, Mitsubishi Gas Chemical) as a polymerizable acrylic acid compound 85
100 parts by weight of epoxy methacrylate (Dicklight UE-8070-60BH Dainippon Ink) and 14.9 parts by weight of azobisisobutyronitrile as a polymerization initiator (curing agent) , Samples Nos. 7 to 10 were prepared by adding 1 part by weight of each of the water-absorbing polymer compounds shown in Table-2. The air leak rate for each of these samples was 2000 to 2500 ml / min (air pressure 2
The impregnation effect test was performed on the test piece (when applied with kgf / cm ² ) (corresponding to the test piece 3 of Example 1) in the same manner as in Example 1, and the results are shown in Table 2.

In Table-2, Aquaric CS-7 is sodium polyacrylate, Arasorp 800F is potassium polyacrylate, Sumikagel is polyvinyl alcohol modified with acrylic acid, and KI gel 201K is maleic anhydride-isobutylene. Is a copolymer of

Table 2 shows that a polymer generally called a water-absorbing polymer has an excellent impregnation effect regardless of the molecular structure.

Example 3 A sealing test was performed in the same manner as in Example 1 using an intake manifold of an actual cast product, and the results are shown in Table-3. The composition ratio of the composition was 83.5 parts by weight of 2-hydroxyethyl methacrylate (trade name: GE-610 Mitsubishi Gas Chemical),
Epoxy acrylate (trade name Dicklight UE-8070)
-60BH Dai Nippon Ink) 14.9 parts by weight, 0.5 parts by weight of lauroylglutamic acid dibutylamide (trade name Coagulin GP-1 Ajimoto), KI gel 2 as a water-absorbing polymer compound
01K (Kuraray) was 1 part by weight, and azobisisobutyronitrile was 0.1 part by weight as a curing agent, for a total of 100 parts by weight.

Table 3 shows that the composition of the present invention has a high sealing effect even when an actual cast product is used as the porous article.

〔The invention's effect〕

As described above, in the composition of the present invention, in the step of washing the porous article or the step of curing with the warm water, the composition flows out of the pores due to the replacement with the intruding water regardless of the size of the pores of the porous article. It is a practically useful composition that is prevented and has a high sealing effect.

Claims (1)

(57) [Claims] 1. A sealed composition containing a polymerizable acrylic acid compound and a polymerization initiator as main components, wherein 0.1 to 3 parts by weight of a water-absorbing polymer compound is further added to 100 parts by weight of the polymerizable acrylic acid compound. A sealing composition to be contained.