JP3008284B1 - Modified silicone sealant for construction - Google Patents

Abstract

An object of the present invention is to provide a modified silicone sealing material for architectural use, which has a low surface tack and a good weather resistance. (A) A rubber-based organic polymer having at least one silicon-containing group that has a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom and can be crosslinked by forming a siloxane bond, B) a silicone surfactant, (C) an air-curable compound, and (D) a molecular weight of 1,
Use is made of a modified silicone sealing material composition for buildings containing at least 000 polyoxyalkylene polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified silicone-based sealing material for buildings, which is filled between joints at the interior and exterior of buildings and joints at joints to prevent the penetration of wind and rain.

More specifically, the present invention relates to a modified silicone-based sealing material which belongs to a family of building sealing materials specified in JIS A 5758 and has good surface tack and weather resistance.

[0003]

2. Description of the Related Art A modified silicone sealing material for construction is provided as one or two components prepared in the form of a paste, which is filled into a joint of a building, applied and cured. The sealing material is a rubber-based organic polymer having a silicon-containing group capable of crosslinking by forming a siloxane bond as a main component (hereinafter, referred to as a modified silicone resin), a curing agent, a curing accelerator, a curing retarder, a plasticizer, A composition consisting of fillers, antioxidants, UV inhibitors, dyes / pigments, etc., because it is economical and has properties such as weather resistance that are generally better than other systems such as polyurethane and polysulfide. In recent years, it has been increasingly used.

[0004] However, the modified silicone-based sealing material has a disadvantage that the surface of the cured product has a large amount of tack and is easily stained during long-term outdoor exposure.

[0005] In order to reduce the tack, an air-curable compound represented by a drying oil is added (Japanese Patent Publication No. 5-82860). This is one of the air-curable compounds
This is due to a mechanism in which the part bleeds and hardens on the surface.

[0006]

However, when this air-curable compound is added, the bleeding proceeds further, and the surface of the cured product has a higher hardness than the interior over a long period of time.
Low elongation. For this reason, surface cracks may occur due to joint expansion and contraction, resulting in poor appearance. Further, there is a disadvantage that the hardening deterioration is remarkable in a thin layer portion generated due to a joint structure and a problem in construction.

In particular, when a modified silicone resin of high molecular weight and monodisperse is used, a uniform crosslinked structure can be obtained, and the curability and the rubber properties of the cured product can be easily adjusted with a good sealing material. However, it was found that the above phenomenon became remarkable when an air-curable compound was added.

Due to the above-mentioned disadvantages, the amount of the air-curable compound must be limited to a small amount, and therefore, the effect of preventing tackiness, which is the original object, cannot be sufficiently obtained.

On the other hand, the plasticizer in the compounding component adjusts the thixotropic property, viscosity and the like of the mixture.
It is an essential component to obtain filling workability such as gunning property and spatula finish, slump property, and flexibility of the mixture.

As the plasticizer, phthalate low molecular weight plasticizers are generally used. When these low molecular weight plasticizers are used, a predetermined workability can be easily obtained by selecting a filler. Although it is possible, physical properties are reduced due to bleeding, that is, tack is generated on the surface, and an increase in modulus and a decrease in elongation due to volatilization of the plasticizer occur in a long term. In particular, when construction is performed at a high temperature, deterioration of physical properties is promoted. Therefore, in combination with an air-curable compound, the effect of the air-curable compound is initially small, but after long-term outdoor exposure, it tends to promote an increase in surface hardness.

On the other hand, polyester, polyether, poly-α-methylstyrene, polybutadiene, butadiene-
General polymer plasticizers such as acrylonitrile copolymer, polychloroprene, polyisoprene, polybutene, and chlorinated paraffin have also been proposed, but plasticization efficiency is lower than that of low-molecular plasticizers, but there is little change in physical properties. . However, a composition that is mixed with various components to form a paste as a sealing material cannot obtain a wide range of compatibility as compared with a low-molecular-weight plasticizer. In particular, there is a disadvantage that the wettability and dispersibility of a solid material are poor, such as an inorganic filler.
Therefore, when an air-curable compound is used to prevent tack, there is a disadvantage that the surface hardness is easily increased from the beginning because of poor compatibility.

The present invention has been made in view of the above-mentioned drawbacks of the present modified silicone-based sealing material, and has been developed in a system in which an air-curable compound is added to a modified silicone resin.
By using a specific silicone compound and a polyoxyalkylene polymer having a molecular weight of 1,000 or more as a polymer plasticizer, compatibility in the system is improved, and an excessive increase in surface hardness of a cured product after aging is moderated. I found that.

[0013]

That is, the present invention provides:
(A) 100 parts by weight of a rubber-based organic polymer having at least one silicon-containing group which has a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom and can be crosslinked by forming a siloxane bond, (B) 0.01 to 5 parts by weight of a silicone surfactant composed of methylpolysiloxane and polyalkylene oxide, (C) 1 to 20 parts by weight of an air-curable compound, and (D) a molecular weight of 1 as a polymer plasticizer The present invention relates to a modified silicone-based sealing material composition for buildings, comprising 2,000 or more polyoxyalkylene polymers.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the rubber-based organic polymer (A) include, for example, a polymer whose main chain is substantially a polymer such as polyether or acryl, into which a reactive silicone functional group is introduced. . The number average molecular weight is from 3,000 to
30,000 is preferred, but 15,000 is more preferred.
~ 20,000, which is generally called a modified silicone resin. As an example of these, "Exester" (produced by Asahi Glass Co., Ltd.), which is already industrially produced, can be used.

The silicone surfactant (B) is a nonionic surfactant mainly composed of dimethylsiloxane as a main chain, wherein the hydrophobic group is composed of methylsiloxane and the hydrophilic group is composed of polyalkylene oxide. The dimethylsiloxane main chain is supplied as a side chain modified copolymer with a Si—C bond or a terminal modified polymer with a Si—O—C bond. This is because various types are industrially produced by adjusting the Si concentration, dimethylsiloxane chain length, alkylene oxide type, etc., and any type can be selected depending on the type of air-curable compound and the matrix system. it can.

Specifically, from each silicone maker,
It can be arbitrarily selected from those sold as silicone surfactants, foam stabilizers for urethane foam, and defoamers. The amount of the silicone surfactant is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the modified silicone resin.

As the air-curable compound (C), a compound having an unsaturated group which is polymerized by oxygen in the air is preferable. Specifically, drying oils such as tung oil and linseed oil, and their modified products, butadiene, chloroprene, isoprene, and liquid polymers obtained by polymerizing or copolymerizing diene-based compounds such as 1,3-pentadiene, and the like. Metamorphosis.

The amount of the air-curable compound is from 1 to 20 parts by weight based on 100 parts by weight of the modified silicone resin.
If the amount is less than 20 parts by weight, the effect of improving the surface tack is insufficient.
If the amount exceeds the weight part, the silicone surfactant of (B),
In the system to which the polyoxyalkylene polymer (D) is added, the surface hardness is significantly increased.

The polyoxyalkylene polymer (D) is a polyoxyalkylene having a molecular weight of 1,000 to 30,000 obtained by polymerizing an alkylene oxide and having no hydrolyzable silicon group. Coalescence is preferred.

Examples of the organic polymer include a hydroxyl-terminated polyoxyalkylene and derivatives thereof. Examples of the derivative include a polymer in which a terminal hydroxyl group is sealed with a hydrocarbon group such as an alkyl group or an alkenyl group via a bond such as an ether bond or an ester bond urethane bond. The blending amount of the polyoxyalkylene polymer is preferably from 1 to 150 parts by weight based on 100 parts by weight of the modified silicone resin (A).

As other compounding agents of the present invention, a curing accelerator, a curing retarder, a plasticizer, a dye / pigment for a filler, an ultraviolet absorber, and other additives are used as required. As a filler, an inorganic filler such as calcium carbonate, talc, kaolin or the like is used as a modified silicone resin 10 in order to impart a proper thixotropic property as a paste as a building sealing material.
Use 150 to 250 parts by weight with respect to 0 parts by weight.

[0022]

Next, the present invention will be specifically described based on examples of the sealing material of the present invention. (Examples 1-3, Comparative Examples 1-2)

According to the base composition shown in Table 1, each component is kneaded with a butterfly mixer and then dispersed with three rolls. Thereafter, the mixture was remixed and degassed with a butterfly mixer to obtain a base. In addition, according to the curing agent formulation shown in Table 1, a curing catalyst, a plasticizer, and a filler were mixed with a butterfly mixer under a nitrogen stream to obtain a curing agent.

[0024]

[Table 1]

The base prepared by the above method: the curing agent is 10:
After mixing at a ratio of 1, the tests shown in the following (1) to (4) were performed. In addition, as a test body, a test body in a JIS A 1439 tensile adhesion test was used, and a primer NEW80 (manufactured by Hitachi Chemical Co., Ltd.) was previously applied to the bonding surface.

(1) Tensile adhesion According to JIS A 1439 tensile adhesion test, tensile stress at 50% elongation (M50), maximum tensile stress (Tmax),
The elongation at break (Eb) was measured.

(2) Surface tack The surface tack after 1 day and 23 days at 23 ° C. and 50% was judged by finger touch.

(3) Weather resistance test: The state of deterioration after irradiation for a predetermined time was observed with a sunshine weather meter (WOM Suga Test Machine Co., Ltd.).

(5) Repetition test of expansion and contraction: After irradiation with a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.) for a predetermined time, a repetition test of ± 30% expansion and contraction was performed at 23 ° C.
This was performed 00 times, and the state of the surface was observed.

The test results are shown in Table 2 below.

[0031]

[Table 2]

[0032]

As described above, in a system in which an air-curable compound is added to a modified silicone resin, the compatibility in the system is improved by adding a specific silicone compound and a high-molecular plasticizer, and the surface of the cured product after aging is improved. The increase in hardness is reduced.

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Claims (1)

(57) [Claims] 1. A rubber-based organic polymer (A) having a hydroxyl group and / or a hydrolyzable group bonded to a silicon atom and having at least one silicon-containing group which can be crosslinked by forming a siloxane bond. (B) 0.01 to 5 parts by weight of a silicone surfactant composed of (B) methylpolysiloxane and polyalkylene oxide,
A modified silicone sealant composition for construction comprising (C) 1 to 20 parts by weight of an air-curable compound, and (D) a polyoxyalkylene polymer having a molecular weight of 1,000 or more as a polymer plasticizer.