JP3413708B2 - Room temperature curable organopolysiloxane composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition at room temperature which gives a rubber elastic body having a good appearance with little avatar when cured, without impairing adhesiveness. The present invention relates to an organopolysiloxane composition, and more particularly to a room temperature-curable organopolysiloxane composition suitable as a building sealing material. 2. Description of the Related Art A room-temperature-curable organopolysiloxane composition which cures at room temperature to a rubber-like elastic material has a cured product having weather resistance, durability, heat resistance, Because of its excellent properties such as cold resistance, it is widely used in various fields. In particular, in the construction field, it is frequently used as an adhesive or a sealing material. [0003] However, recently, acrylic resin electrodeposition coating materials and fluororesin coating materials, which have good weather resistance as a building exterior material but have poor adhesion on the surface, have come to be widely used. Conventional room temperature curable organopolysiloxane compositions often have insufficient adhesion to such coating materials and the like. [0004] One-part and two-part types are known as room-temperature-curable organopolysiloxane compositions for use in building sealing materials. , Also, in the case of two-pack type, at the time of mixing and casting,
Bubbles are mixed in, and as a result, a number of crater-shaped dents (called avatars) are generated on the surface of the cured sealing material, which has a disadvantage in that the appearance is impaired. [0005] Therefore, in the case of a two-pack type, a defoaming operation is performed after mixing. Further, for the two-pack type, there has been proposed a room temperature curable organopolysiloxane composition to which an organic carboxylic acid and / or an organic acid anhydride is added for preventing avatar (Japanese Patent Application Laid-Open No. 61-225250, U.S. Pat. 54
No. 05889). However, the organopolysiloxane composition curable at room temperature to which an organic carboxylic acid and / or an organic acid anhydride is added has a problem that the pot life is short and the workability in actual on-site construction is poor. Conventionally, as a room temperature-curable organopolysiloxane compound using calcium carbonate as a filler, one using colloidal calcium carbonate has been proposed in JP-A-5-39422. Although it is effective in preventing the occurrence of cracks, the adhesiveness after immersion in hardly adherent adherends was not sufficient. [0008] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a room-temperature-curable organopolysiloxane composition having a good appearance with little occurrence of avatars on the surface when cured, without impairing the adhesion to a substrate. Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that diorganopolysaccharides having both ends of a molecular chain blocked with hydroxyl groups. Siloxane, one or two or more groups selected from substituted aminooxy groups represented by the following general formula (1) and the following general formula (2) bonded to a silicon atom per molecule:
In a room temperature-curable organopolysiloxane composition using a nitrogen atom-containing organosilicon compound having at least 01 and calcium carbonate as a filler, an average primary particle size treated with carboxylic acid is 0.1 μm or less of calcium carbonate. 50% by weight or more of the carboxylic acid is resin acid, and the treatment amount is 2.5% by weight based on calcium carbonate.
By using the following calcium carbonate, it adheres well to hardly adherent adherends, hardly generates avatars on the cured product, and has a good appearance at room temperature curable organopolysiloxane composition. The present inventors have found that the present invention can be applied, and have accomplished the present invention. Accordingly, the present invention provides: (a) 100 parts by weight of a diorganopolysiloxane in which both ends of the molecular chain are blocked with a hydroxyl group; (b) the following general formula (1) and the following formula (1) bonded to a silicon atom per molecule: 0.1 to 30 parts by weight of a nitrogen atom-containing organosilicon compound having an average of 2.0 or more of one or more selected from the substituted aminoxy groups represented by the general formula (2); Acid, dehydroabietic acid, dextropimaric acid, levopimaric acid, palustric acid, sandaracopimaric acid, a carboxylic acid containing 50% by weight or more of a resin acid in an amount of 2.5% by weight or less based on calcium carbonate Room temperature curable organopolysiloxane comprising 1 to 200 parts by weight of treated calcium carbonate having an average primary particle size of 0.1 [mu] m or less. A composition is provided. [0011] Hereinafter, the present invention will be described in more detail. As described above, the room-temperature-curable organopolysiloxane composition of the present invention comprises (a) a diorganopolysiloxane in which both molecular chain terminals are blocked with hydroxyl groups, (b) a nitrogen-containing organosilicon compound, and (c) It contains calcium carbonate as an essential component. The diorganopolysiloxane of which the both ends of the molecular chain of the component (a) are blocked with hydroxyl groups is the main ingredient of the composition of the present invention. it can. Specifically, a hydroxyl-terminated diorganopolysiloxane represented by the following average composition formula is exemplified. Embedded image In the above formula, examples of the substituted or unsubstituted monovalent hydrocarbon group for R include alkyl groups such as methyl, ethyl, propyl and butyl, alkenyl groups such as vinyl and allyl, and cyclohexyl. Cycloalkyl groups such as a cycloalkyl group, cycloalkenyl groups such as a cyclohexenyl group, aryl groups such as a phenyl group and a tolyl group, aralkyl groups such as a benzyl group and a phenylethyl group, a chloromethyl group,
Examples thereof include those having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, such as halogenated hydrocarbon groups such as 3,3-trifluoropropyl group and cyanohydrocarbon groups such as cyanoethyl group. Group, phenyl group, 3,3,3-
A trifluoropropyl group is preferred, and a methyl group is particularly preferred. In order for the cured product obtained from the composition of the present invention to exhibit good rubber elasticity and to have excellent mechanical strength, this component (a) should be at least 300 centipoise at 25 ° C., more preferably , 1,000 cP or more. The upper limit of the viscosity is not particularly limited, but when the composition of the present invention is used for a sealing material or the like, it is required that the composition has a certain degree of fluidity. It is desirable that the viscosity be 100,000 centipoise or less, especially 10,000 centipoise or less at a temperature of ° C. The nitrogen-containing organosilicon compound (b) is a crosslinking agent which acts on the component (a) as a main component and releases a hydroxyamino compound to cause a curing reaction. One or more groups selected from substituted aminoxy groups represented by the following general formulas (1) and (2) bonded to silicon atoms per molecule have an average of 2.0
It has one or more. Embedded image In the above general formula (1), examples of the monovalent hydrocarbon group for R ¹ and R ² include alkyl groups such as methyl group, ethyl group and propyl group, aryl groups such as phenyl group, benzyl group and the like. C1-C10 thing, such as an aralkyl group, is mentioned. In the general formula (2), examples of the divalent organic group for R ³ include the following groups. Embedded image As the component (b), there can be mentioned a polyaminoxysilane represented by the following formula (3). Embedded image (Wherein R ⁴ is the same or different, substituted or unsubstituted 1
A valent hydrocarbon group, Y is a group represented by the above general formula (1) or (2), b is 0, 1 or 2, and n is an integer of 0-10. The following are specific examples of the polyaminoxysilane. Embedded image Further, as a component (b), -OS
a cyclic or linear organopolysiloxane having a unit of i (R ⁴ ) (Y) — (wherein R ⁴ and Y have the same meanings as described above); Is exemplified. Embedded image The nitrogen atom-containing organosilicon compound (b) used in the composition of the present invention is a crosslinking agent which causes a curing reaction with the organopolysiloxane (a).
It is necessary that the molecule has an average of 2.01 or more, preferably 2.01 to 10, of the aminoxy groups represented by the above formulas (1) and (2) in the molecule. If the number of aminoxy groups is less than this, the curing reaction becomes insufficient. Therefore, when a compound having two aminoxy groups in one molecule is used alone as the component (b), the desired curing reaction does not sufficiently occur. If you have two of them,
When used in combination with a compound having three or more aminoxy groups in the molecule, a silicone rubber having excellent rubber elasticity can be obtained. The amount of the component (b) is 100 parts (parts by weight, hereinafter the same) of the organopolysiloxane of the component (a).
Is preferably 0.1 to 30 parts, more preferably 1 to 10 parts. If the amount is less than 0.1 part, the curing may be insufficient. On the other hand, if the amount is more than 30 parts, the curing may be delayed, and the cured rubber layer may be deteriorated. There is. The calcium carbonate of the component (c) is a component which is a feature of the present invention as described above.
0% by weight or more is carboxylic acid-treated calcium carbonate which is a resin acid. The resin acids used here are those selected from abietic acid, dehydroabietic acid, dextropimal acid, levopimaric acid, palustric acid, and sandaracopimalic acid. The carboxylic acid other than the resin acid is not particularly limited, but preferably has 15 or more carbon atoms. For example, stearic acid, oleic acid, palmitic acid and the like can be used. The calcium carbonate treated with the above treating agent has an average primary particle size of 0.1 μm or less, especially 0.03 to
Use the one with 0.1 μm. If it is larger than 0.1 μm, the adhesiveness of the composition will be impaired. On the other hand, if the particle size is too small, the viscosity of the composition becomes high, and the workability may decrease. The amount of calcium carbonate treated by the above treatment agent is 2.5% by weight or less based on calcium carbonate,
In particular, it is 1.5 to 2.5% by weight. If the treatment amount is more than 2.5% by weight, the adhesiveness of the composition is impaired. If the amount of treatment is too small, it becomes difficult to mix the diorganosiloxane in which both ends of the molecular chain (a) are blocked with a hydroxyl group, and the mixed paste may not have non-sag properties. is there. (C) The amount of the calcium carbonate component is as follows:
1 part per 100 parts of organopolysiloxane of component (a)
The content is preferably in the range of from 200 to 200 parts, especially from 10 to 150 parts. The composition of the present invention may be used in combination with other fillers if necessary. Examples of such fillers include crystalline silica fine powder, amorphous silica fine powder, silica hydrogel, silica aerogel, Examples include diatomaceous earth, calcium silicate, aluminum silicate, titanium oxide, aluminum oxide, zinc oxide, iron oxide, carbon black, graphite, mica, clay, bentonite, and the like. It should be noted that it is optional to incorporate various additives such as a pigment, a heat resistance improver, and a flame retardant into the composition of the present invention as long as the object of the present invention is not impaired. EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight. Examples 1 and 2 and Comparative Examples 1 to 4 The treated calcium carbonates A to F shown in Table 1 were added to 100 parts of dimethylpolysiloxane having a viscosity at 25 ° C. of 5000 cSt and both ends of a molecular chain blocked with hydroxyl groups. 67 parts of each were added, mixed with a Shinagawa mixer, and kneaded with three rolls to prepare a non-flowable paste-like base mixture. Next, the compounds represented by the following formulas (i) and (ii) are weight ratio (i) / (ii) = 95/5 to 100 parts of the base mixture.
2.5 parts of the mixture mixed in the ratio of
According to the method of JIS A5758 “Sealant for building”, an H-shaped block having the shape of FIG. 1 and 20 × 20 × 200
A virtual joint having a thickness of mm was prepared (the H-type block was formed after applying primer AQ-1 manufactured by Shin-Etsu Chemical Co., Ltd. to the surface to be adhered and air-drying for 30 minutes). In this case, the H-shaped block is formed by surrounding the sample 1 with the adherends 2 and 2 and the spacers 3 and 3. After curing the H-shaped block at 20 ° C. for 7 days, the spacer 3 is removed and the H-type block is removed at 50 ° C. for 7 days. After curing, the film was pulled in the direction of the arrow, the maximum tensile strength was measured, and the fracture state was visually observed. 48 hours after filling the joints, the virtual joints were observed for the surface condition of the cured joints. Table 2 shows the results. Embedded image [Table 1] [Table 2] * 1 AG-200: Acrylic electrodeposition coated plate * 2 Dick flow metallic: Fluororesin coated plate * 3 Deterioration condition: Initial stage: Leave at 20 ° C for 7 days, remove the spacer, cure at 50 ° C for 7 days, and then submerge ... 7 days after immersion of the sample in the initial state at 50 ° C * 4 Tmax: Maximum tensile strength * 5 CF: Cohesive failure rate * 6 Joint surface condition: ○: Almost no avatars ×: Many avatars are observed The organopolysiloxane composition curable at room temperature of the present invention is a calcium carbonate treated with a carboxylic acid and having an average primary particle size of 0.1 μm or less, and 50% by weight or more of the carboxylic acid. Is resin acid, and the treatment amount is 2.5
By using calcium carbonate of not more than% by weight, an adhesive property after water immersion is good, and a room-temperature-curable organopolysiloxane composition having almost no avatar can be obtained, which can be suitably used as a building sealing material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an H-shaped block created in Examples and Comparative Examples.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaharu Sato 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Masatoshi Miyake Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP-A-5-39422 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) C08L 83/06 C08K 3/26 C08K 5/54 C08K 9/04

Claims (1)

(57) [Claims 1] (a) 100 parts by weight of a diorganopolysiloxane in which both ends of a molecular chain are blocked with a hydroxyl group, (b) The following general formula bonded to a silicon atom per molecule: 0.1 to 30 parts by weight of a nitrogen-containing organosilicon compound having an average of 2.0 or more of one or more groups selected from (1) and substituted aminoxy groups represented by the following general formula (2): , Embedded image (C) 2.5% by weight based on calcium carbonate by a carboxylic acid containing 50% by weight or more of a resin acid selected from abietic acid, dehydroabietic acid, dextropimaric acid, levopimaric acid, palustric acid, and sandaracopimaric acid A room temperature-curable organopolysiloxane composition comprising 1 to 200 parts by weight of calcium carbonate having an average primary particle size of 0.1 μm or less and treated in the following amount.