JPH07316538A - Composition for sealing material - Google Patents

Abstract

PURPOSE:To obtain a sealing material composition useful for a siding board, etc., by blending a room temperature curing composition comprising a specific polymer as a base with an amino group-containing silane coupling agent and an alkoxysilyl group-containing schiff base compound. CONSTITUTION:(A) A room temperature curing composition comprising a plasticized reactive silicon group-containing polyoxyalkylene-based polymer as a base blended with a plasticizer (e.g. dibutyl phthalate or diheptyl phthalate) is blended with (B) 0.1-1wt.% of an amino group-containing silane coupling agent (e.g. 3-aminopropyltriethoxysilane) and (C) 0.1-1wt.% of an alkoxysilyl group-containing schiff base compound [e.g. N-(1,3- dimethylbutylidene)-3-(triethoxysilyl)-1-propamine].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction sealing material used for joints of building components, filling around window frames, glass fitting, and the like, and more particularly, it has good adhesiveness and extensibility. The present invention relates to a modified silicone-based sealant composition.

[0002]

2. Description of the Related Art A sealing material for construction is required to have physical properties such that a joint or a gap filled with the sealing material does not crack or peel even if it changes due to temperature, vibration or the like. Especially when constructing siding boards, low modulus products with good adhesion and extensibility are often required. In the case of a modified silicone sealant based on a polyoxyalkylene polymer containing a reactive silicon group as a base material, roughly two methods have been conventionally used to obtain a composition having a low modulus. One is devising in terms of polymer synthesis (for example, JP-A-5-287261), by adjusting the number of reactive silicon groups or increasing the length of the polyoxyalkylene chain between the reactive silicon groups. Alternatively, it is a technique of making it difficult to crystallize and taking a molecular structure, and the other is a device in terms of compounding the composition. The reduction of the modulus by blending the plasticizer can be freely and simply performed regardless of the polymer structure, and is an industrial means of extremely high practicality.

[0003]

However, in a moisture-curable composition such as a modified silicone-based sealing material, a large amount of an oily plasticizer is mixed with a hydrolysis reaction of a reactive silicon group or a surface of an adherend. It slows the progress of the bonding reaction more than necessary, and hinders the adhesion between the sealing material and the adherend. In this case, when a large amount of a silane coupling agent is added to improve the adhesive strength, the coupling agent also reacts with the polymer to increase the crosslink density, resulting in a significant increase in the cured product modulus. The increase in modulus when the sealant hardens means that when the joint gap moves and opens,
If the sealing material is not stretched, it is unavoidable that a crack is generated or detached from the adherend. As a result of earnestly advancing the research on such a compounding aspect, the present inventors have achieved a result to solve the above problems and completed the present invention.

[0004]

SUMMARY OF THE INVENTION The present invention provides a room temperature curable composition comprising a plasticizing reactive silicon group-containing polyoxyalkylene polymer as a base material, an amino group-containing silane coupling agent, and an alkoxysilyl group. Provided is a modified silicone-based sealant composition containing 0.1 to 1 weight percent of each group-containing Schiff base. The term "plasticizing" means "containing a plasticizer".

The reactive silicon group-containing polyoxyalkylene used in the composition of the present invention is a modified polyoxyalkylene in which a hydrolyzable group and / or a hydroxyl group is directly bonded to a silicon atom in a polymer molecule. The molecular structure is known, but as a typical example, there is JP-A-50.
-156599, 54-6096, 55-82
No. 123, No. 55-131022, No. 55-1371.
No. 29, No. 57-126823, No. 59-78223.
No. 62-230822, 63-83131,
JP-A-3-4782, JP-A-3-72527, 3-1
No. 22152 and the like. In addition, as a marketed product, MS-20A, MS-15A modified, MS-203
(All manufactured by Kanegafuchi Chemical Industry Co., Ltd.) and the like.

As the plasticizer used in the present invention, various commercially available products can be used. Specific examples thereof include phthalic acid esters such as dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, butyl benzyl phthalate and butyl phthalyl butyl glycolate, dibasic acid esters such as dioctyl adipate and dioctyl sebacate, tricresyl phosphate. , Phosphoric acid esters such as tributyl phosphate, polyester plasticizers composed of dibasic acids and glycols, polyethers such as polypropylene glycol and its derivatives, and oligomers of poly-α-methylstyrene and polystyrene. These plasticizers may be used alone or in combination, and the compounding amount thereof may be set in accordance with the physical properties of the composition, but as a low modulus product, 40 to 120 parts (reactive silicon group-containing poly The range of 100 parts by weight of oxyalkylene, based on 100 parts by weight, and the same hereinafter) is preferable.

Next, the composition of the present invention may be blended with a filler for the purpose of adjusting the fluidity at the time of filling as a sealing material or the physical properties. Specific examples include fume silica, precipitated silica, silicic acid anhydride, carbon black,
Calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite,
Ferric oxide, activated zinc white, hydrogenated castor oil and the like are used. The compounding amount is about 50 to 150 parts in a suitable range as a low modulus product. Further, a known curing catalyst can be added to the composition of the present invention. As a specific example,
Dibutyltin dilaurate, tin dioctylate, dibutyltin diacetyl, dibutyltin bistriethoxysilicate,
Examples include dibutyltin bisacetylacetonate and dibutyltin bis-2-ethylhexanoate. For the composition of the present invention, the compounding amount is within 2 parts. The composition of the present invention includes
Further, if necessary, a pigment, an antiaging agent, an ultraviolet absorber, a water removing agent, a diluting solvent, a polymer for adjusting physical properties or a low molecular weight additive or a modifier can be added.

Therefore, the greatest feature of the composition of the present invention is that, in addition to the above-mentioned composition, a silane coupling agent having an amino group and a Schiff base compound having an alkoxysilyl group are further compounded in respective quantitative ranges. . When these additives are used alone instead of in combination, or even when they are combined and the compounding amount is outside the respective quantitative range, preferable properties of the composition of the present invention cannot be obtained.

Specific examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N- (2-anomyethyl) 3-aminopropyltrimethoxysilane and N- (2-anomyethyl) 3. -Aminopropylmethyldimethoxysilane and the like can be exemplified.
The addition amount ratio of this additive to the total amount of the composition is preferably within 1% (weight basis, the same applies hereinafter), and if it exceeds 1%, the modulus of the cured product of the composition becomes excessive, which is not preferable.
On the other hand, if it is 0.1% or less, satisfactory adhesive strength cannot be obtained.

Next, the Schiff base compound having an alkoxysilyl group is specifically N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-.
Propanamine, N- (1,3-dimethylbutylidene)-
3- (trimethoxysilyl) -1-propanamine, N-
Examples thereof include (1,3-dimethylbutylidene) -3- (methyldimethoxysilyl) -1-propanamine. This compound is considered to cause more blooming near the interface between the material and the adherend due to the slower rate of conversion to a silanol group than a silane coupling agent having an amino group. It is thought that the adhesive strength with However, when this compound is added in an amount of more than 1% with respect to the total amount of the composition, the action as a dehydrating agent is predominant, only the surface is rapidly solidified at the time of curing, and the internal curing does not proceed. 0.1 to 1 as above
%.

It is necessary to suppress the water content of all the above-mentioned compounded materials in advance by dehydration, drying, etc. to the lowest possible level. Special attention should be paid to the filler. It is a necessary condition for ensuring the storage stability of the composition. The composition of the present invention can be prepared by kneading the above-mentioned compounding materials with a conventional kneading machine such as a paint mill, a kneader, and a ladle machine.

When mixed into a container such as a cartridge so as not to come into contact with water after mixing, a one-component type sealing material is obtained, and in order to obtain a dichotomous type sealing material, a catalyst, an amino-containing silane coupling agent and an alkoxysilyl group are used. A two-component type can be obtained by mixing the contained Schiff base with a small amount of a filler and a plasticizer to form a curing agent, and mixing a modified silicone resin, a filler, a plasticizer, and the like to form a main component. Next, the characteristics of the composition of the present invention will be described with reference to representative examples.

[0013]

【Example】

Example 1 Methyldimethoxylyl group-containing polyoxypropylene having the composition shown in Table 1 (trade name, MS-20A, manufactured by Kanebuchi Chemical Industry Co., Ltd., average molecular weight of about 8,000, viscosity of 130 ± 5)
0 poise) and di (n-octyl) phthalate were mixed and stirred, and then calcium carbonate as a filler and titanium oxide as a pigment were added and mixed and stirred for 12 hours. Separately from this, dibutyltin laurate and-(1,3, -dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine (manufactured by Chisso Corporation, trade name S340), 3-
Aminopropyltriethoxysilane (manufactured by Chisso Corporation,
Brand name S330) was mixed for 5 minutes. Next, these two mixtures were kneaded together to obtain a room temperature curable composition of the present invention. A test body was prepared from this composition according to JIS A 5758 using a commercially available siding board. After predetermined curing, the cured product was subjected to a tensile adhesion test under standard conditions, and the results are shown in the table.

Examples 2 and 3 In the same manner as in Example 1, the components were mixed in the proportions shown in Table 1 to obtain cured products.

Comparative Examples 1 and 2 As Comparative Example 1, a case where S340 was not included and a Comparative Example 2 where S330 was not included were examined.

[0016]

As shown in Table 1, the room temperature cured product of the composition of the present invention adheres well to a siding board and has a very large elongation. On the other hand, as can be seen from the comparative example, S3
If 40 is not added, the modulus of the cured product will increase too much to obtain a sufficient adhesive strength, resulting in a drawback that the elongation becomes small. On the contrary, if S330 is not added, sufficient adhesive force cannot be obtained, and further, it is found that the surface is hardened at the time of hardening and the inside is hard to be hardened. As described above, the sealant composition of the present invention is used as a modified silicone-based sealant only when both the amino group-containing silane coupling agent and the alkoxysilyl group-containing Schiff base compound are blended in a specific range. Since the tensile stress (modulus) can be kept small and excellent adhesiveness and extensibility can be provided, it is particularly suitable for siding boards and construction.

[0017]

[Table 1] * 1 The blending amount is shown in parts by weight, but the value in parentheses is the weight percentage with respect to the total amount. * 2 CF: Cohesive failure, AF: Interface peeling

Claims (1)

[Claims] 1. A room temperature-curable composition comprising a plasticizing reactive silicon group-containing polyoxyalkylene polymer as a base material, and an amino group-containing silane coupling agent and an alkoxysilyl group-containing Schiff base compound each added to a room temperature curable composition of 0.1. A modified silicone-based sealant composition containing 1 to 1 weight percent.