JP2918418B2 - Room temperature curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room-temperature-curable composition which cures at room temperature into a rubbery state by reacting with moisture in the atmosphere, and more particularly to a room-temperature-curable composition useful as a sealing material having excellent physical properties after curing. About things.

[0002]

2. Description of the Related Art As a polymer which reacts with moisture in the atmosphere and cures into a rubbery state, for example, as described in JP-A-58-41291, an oxy group having an ether type allyl olefin group at its terminal is known. VIII.
In the presence of a group _III transition metal, a compound of the general formula X _3-a SiR _a H (where R is a group selected from a monovalent hydrocarbon group and a halogenated monovalent hydrocarbon group, a is 0, 1 or 2, X Represents a group or an atom selected from a halogen atom, an alkoxy group, an acyloxy group and a ketoximate group.)
A polyether having a hydrolyzable silyl group at a terminal has been proposed.

A curable composition containing such a polymer has excellent performance, but depending on the composition,
Workability and tensile properties after curing (low modulus, high elongation) are insufficient. Therefore, in order to improve the elongation properties in particular, for example, as described in JP-A-59-138259, it is preferable to use an easily dispersible cubic calcium carbonate having an average particle size of 0.01 to 1.0 μm. Proposed.

[0004]

However, as described in the same publication, this easily dispersible cubic calcium carbonate is precipitated calcium carbonate, and when such precipitated calcium carbonate is used, it is synthesized. Due to the problem of the method, it contains a large amount of water, so that it is not possible to remove much water even when dried, and there is a problem in storage stability. Further, when a dehydrating agent such as vinyltrimethoxysilane or tetraethoxysilane is used, a large amount of water is required due to the amount of water, and there is a problem that the curing speed becomes extremely slow or extremely expensive. .

The present invention solves the above-mentioned conventional problems and provides a room-temperature-curable composition useful as a sealing material having a high curing rate, excellent storage stability, and excellent physical properties after curing. It was done for the purpose of doing.

[0006]

According to the present invention, the main chain is made of polyether.
An ether, polymer of molecular weight 4,000～30,000 having crosslinkable hydrolyzable silyl group at the terminal (A)
100 parts by weight, a higher fatty acid having a specific surface area of 15,000 cm ² / g or more and a surface having 8 or more carbon atoms and a salt or resin thereof
30 parts by weight or more of heavy calcium carbonate (B) treated with an acid or a salt thereof , and curing catalyst (C) 0.1 to 10
It is a room temperature curable composition characterized by comprising: parts by weight.

As the polymer (A) used in the present invention, for example, an oxyalkylene polymer having an ether type allyl olefin group at a terminal is prepared by subjecting _a compound represented by the general formula X _3-a SiR _a H (Wherein, R is a group selected from a monovalent hydrocarbon group and a halogenated monovalent hydrocarbon group, a is 0, 1 or 2, X is a group selected from a halogen atom, an alkoxy group, an acyloxy group and a ketoximate group, or Which represents an atom.)
A polyether having a hydrolyzable silyl group at a terminal and having a molecular weight of 4,000 to 30,000 is used.

[0008] When the molecular weight of the polymer (A) is less than 4,000, the resulting cured product does not have sufficient elongation.
If it exceeds 30,000, the viscosity becomes too large, and the workability in the compounding step is reduced.

In the present invention, the heavy calcium carbonate (B) has a specific surface area of 15,000 cm ² / g or more, preferably 18,000 cm ² / g or more, and
Higher fatty acids having 8 or more carbon atoms and salts or resin acids thereof and
Those that have been treated with a salt of are used. Specific surface area is 1
If it is less than 5,000 cm ² / g, a cured product having good tensile properties cannot be obtained.

As the heavy calcium carbonate (B), calcite-type crystalline limestone is mechanically pulverized and further classified into heavy calcium carbonate having a large specific surface area. Small in diameter with carbon surface
Those treated with several or more higher fatty acids and salts thereof or resin acids and salts thereof are preferably used.

[0011] Heavy calcium carbonate does not contain much water like precipitated calcium carbonate, and therefore can be dried easily.
Easy to dry, dehydrating agents such as vinyltrimethoxysilane and tetraethoxysilane can be reduced to a very small amount. That is, a room-temperature-curable composition having rapid curability can be obtained.

A higher fatty acid having 8 or more carbon atoms for treating the surface of heavy calcium carbonate (B) and a salt or resin acid thereof;
Examples of the surface treating agent composed of a salt thereof include, for example , unsaturated fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and alginic acid; oleic acid, elaidic acid, linoleic acid, and ricinoleic acid. And alicyclic carboxylic acids such as naphthenic acid, resin acids such as abietic acid and salts thereof such as sodium, potassium and ammonium.

In the present invention, the amount of the heavy calcium carbonate (B) is at least 30 parts by weight based on 100 parts by weight of the polymer (A). If the amount is less than 30 parts by weight, a cured product having good physical properties (high elongation) cannot be obtained.

In the present invention, a silanol condensation catalyst is suitably used as the curing catalyst (C), and examples thereof include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin bisacetylacetonate, and tin octylate.

The amount of the curing catalyst (C) added depends on the amount of the polymer (A)
0.1 to 10 parts by weight with respect to 100 parts by weight. If the added amount is less than 0.1 part by weight, the effect of accelerating curing is small,
If the amount exceeds 10 parts by weight, the modulus of the obtained cured product is significantly reduced.

Further, various fillers can be added to the room temperature curable composition of the present invention. Examples of such a filler include magnesium carbonate, hydrated silicic acid, silicic anhydride, calcium silicate, silica, titanium dioxide,
Clay, talc, carbon black and the like. These fillers may be used alone or in combination of two or more.

Further, the room temperature-curable composition of the present invention can further enhance the elongation properties after curing and reduce the modulus by adding a plasticizer. Examples of the plasticizer include phosphates such as tributyl phosphate and tricresyl phosphate; phthalate esters such as dioctyl phthalate; aliphatic monobasic esters such as glycerin monooleate; dibutyl adipate; and fats such as dioctyl adipate. And polyethers such as aromatic dibasic acid esters and polypropylene glycol. These may be used alone or in combination of two or more.

The room temperature curable composition of the present invention further comprises:
Pigments, ultraviolet absorbers, antioxidants and the like can be added.

[0019]

The room temperature curable composition of the present invention has a main chain of polyether.
An ether, polymer of molecular weight 4,000～30,000 having crosslinkable hydrolyzable silyl group at the terminal (A) 1
00 parts by weight, a higher fatty acid having a specific surface area of 15,000 cm ² / g or more and a surface having 8 or more carbon atoms and a salt or resin acid thereof
And heavy calcium carbonate (B) treated with its salt
By comprising 30 parts by weight or more and 0.1 to 10 parts by weight of the curing catalyst (C), the dried heavy calcium carbonate does not contain much water unlike the precipitated calcium carbonate, and thus has excellent storage stability. In addition, the amount of dehydrating agent such as vinyltrimethoxysilane and tetraethoxysilane can be reduced to a very small amount. The body has a large specific surface area in the reaction product of the polymer (A),
Since the heavy calcium carbonate (B) treated with the above-mentioned specific acid and its salt is appropriately dispersed, it has excellent tensile properties.

[0020]

EXAMPLES The present invention will be clarified below by giving Examples and Comparative Examples of the present invention. Preparation of calcium carbonate As shown in Table 1, calcium carbonate was prepared.

[0021]

[Table 1]

[0022]

Examples 1 to 3 and Comparative Examples 1 to 3 Polymers having a main chain of polyether and having a crosslinkable hydrolyzable silyl group at the terminal (A) were manufactured by Kanebuchi Chemical Co., Ltd. 5A03 "(molecular weight 8500),
Calcium carbonate shown in Table 1 as calcium carbonate
Using dibutyltin bisacetylacetonate as a curing catalyst (C), the composition of Examples 1 to 3 and Comparative Examples 1 to 3 shown in Table 2 was blended by the following method.

After the calcium carbonate was dried at 120 ° C. for 2 hours, “Silyl 5A03” and a plasticizer dioctyl phthalate were mixed with a planetary mixer, and further dried at 110 ° C. under reduced pressure for 3 hours. Mix,
The mixture was uniformly mixed to obtain a room temperature curable composition.

Measurement method of physical properties Measurement of tack free time According to JIS A5758, temperature 23 ° C, humidity 60% R
H. Tensile test of cured product Each of the obtained room-temperature curable compositions has a thickness of 2 m.
m sheet was prepared and cured at 20 ° C. and 60% RH for one week, then a No. 3 dumbbell test piece was prepared according to JIS K6301, and a tensile test was performed at a speed of 50 mm / min.
Table 2 also shows the obtained results.

Storage Stability The change in tack-free time after one week at 50 ° C. in a sealed state was measured. In Table 2, ○ indicates that the tack free time delay was 1.5 times or less, and x indicates that the tack free time delay exceeded 1.5 times.

[0026]

[Table 2]

As is clear from Table 2, all of Examples 1 to 3 of the present invention have a small tack-free time, are excellent in storage stability, and are excellent in tensile properties.
On the other hand, when heavy calcium carbonate having a small specific surface area is used as in Comparative Examples 1 and 2, tensile properties are poor, and when colloidal calcium carbonate is used as in Comparative Example 3, Poor storage stability.

[0028]

As described above, the room temperature curable composition of the present invention has a composition as described above, so that a cured product having a high curing rate, excellent storage stability and excellent tensile properties can be obtained. And can be suitably used as a sealing material.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 71/00-71/03 C08K 9/04 C09K 3/10 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) a polyether having a main chain having a crosslinkable hydrolyzable silyl group at a terminal having a molecular weight of 4,000 to
100 parts by weight of a 30,000 polymer (A) and a high surface having a specific surface area of 15,000 cm ² / g or more and a carbon number of 8 or more.
Room temperature characterized by comprising 30 parts by weight or more of heavy calcium carbonate (B) treated with a tertiary fatty acid and a salt thereof or a resin acid and a salt thereof , and 0.1 to 10 parts by weight of a curing catalyst (C). Curable composition.