JP2000274041A - Modified silicone sealing material for construction of siding board wall material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified silicon based sealing material for construction of a siding board excellent in productivity regarding construction work and durability of its appearance. SOLUTION: A modified silicone sealing material for construction is used which is comprised of, based on 100 pts.wt. of a rubber based organic polymer having a hydroxyl group coupled to silicon atom and/or a hydrolytic group and having at least one silicon-containing group which can be crosslinked by forming a siloxane bond, 5 to 20 pts.wt. of epoxy resin, 3 to 7 parts by weight of an air-hardenable material, 4 to 8 pts.wt. of a photo-setting resin, 0.4 to 0.8 pts.wt. of a benzotriazole ultraviolet absorber, 1.0 to 1.5 pts.wt. of a hindered phenol antioxidant, 75 to 90 pts.wt. of a phthalic acid ester plasticizer, 240 to 270 pts.wt. of a filler, 10 to 15 pts.wt. of an anti-drip stiffener, 1 to 2 pts.wt. of a tetravalent tin compound, and 7 to 10 pts.wt. of epoxysilane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Sealing materials are filled between joints of interior and exterior parts of a building and joints of joints to prevent infiltration of wind and rain. However, the present invention uses a siding board for at least one of the joint members. The present invention relates to a modified silicone sealing material for siding board wall materials suitable for construction.

[0002] More specifically, the present invention relates to a modified silicone-based sealing material which belongs to a building sealing material system defined in JIS A 5758 and has excellent workability, appearance and durability.

[0003] Modified silicone-based sealing materials include modified silicone resins as main materials, curing agents, curing accelerators, curing retarders, plasticizers, fillers, antioxidants, ultraviolet inhibitors, air-drying accelerators, dyes / pigments. The composition is excellent in economical efficiency, and has properties such as weather resistance, which are generally superior to other systems such as polyurethane and polysulfide.

[0004]

2. Description of the Related Art Modified silicone-based sealing materials for construction are provided as one or two components which are prepared in the form of a paste. However, it has a drawback that it is difficult to comprehensively satisfy, for example, good workability during work, beautiful finish, and durability for preventing long-term invasion of wind and rain, which is the final purpose. Especially in recent years, ceramic siding boards, which are frequently used for wall materials of detached houses, have poor dimensional stability, and shrinkage gradually progresses even after being incorporated in the building, and as a result the joints are expanded, so sealing There was a disadvantage that cracks and peeling of the material easily occurred.

[0005] With respect to the improvement of these properties, a great number of proposals have been made as a sealing material or as a curable composition as disclosed in Japanese Patent Application Laid-Open Nos. 5-287776 and 5-287189. It is intended only for the required characteristics of the building, and it is effective only in a laboratory environment without considering the actual situation of the construction site. No proposal has been made to satisfy the characteristics.

[0006] The composition of the architectural sealant must be proposed in view of the actual construction site conditions.

[0007] The construction of the building sealing material is performed by cleaning the seal portion, loading the backup material, applying a masking tape to prevent contamination due to adhesion of the sealing material on the surface, applying a primer, filling the sealing material with a caulking gun, and sealing the surface of the sealing material. Finish with a spatula finish → remove masking tape → cure. Architectural sealants must have a formulation suitable for these operations. It must have a suitable viscosity that is easy to handle and that does not cause sagging or slipping. The viscosity is 3,000 to 3,50
Must be 0 poise.

[0008] Furthermore, since sufficient time must be taken from filling of the sealing material to finishing, it is necessary to prepare a compound having a long curing time. However, in this case, the time required for the semi-rubber-like elastic body in the intermediate stage becomes long, It is necessary to take measures to prevent the vertical joint from slipping because it cannot bear its own weight. Normally, the curing reaction is performed in a composition adjusted for each season, the viscosity is within the proper range and the potable working time at the filling site where filling is possible is at least 5 hours, the finishing time after filling is 2 hours or more, and the curing time Is required to be within 3 days.

[0009] The finishable time begins with the modified silicone-based sealing material not forming a uniform increase in viscosity when exposed to the outside air during curing, but first forming a thin skin on the surface. This is a characteristic that must be carefully considered because it will cause serious problems. In addition, the pot life and finish time vary not only with the temperature at that time, but also with the weather and the location of the construction on the south or north side. Must have the margin.

It is preferable to shorten the pot life as much as possible in consideration of slip control alone. However, this will inevitably increase the curing speed, making it impossible to take the time for surface finishing, and removing the sealing material when removing the masking tape. Will not be in line with the demands from the construction site.

As described above, the basic characteristics required as a sealing material to be considered before curing are both rheological characteristics and chemically reactive characteristics, and these characteristics fluctuate under the influence of external temperature. I do. Therefore, adaptability to each season must be considered. As a matter of fact, there cannot be a certain formula that can be applied throughout the year, and a sealant of a formula must be provided for each season. That is, in order to obtain appropriate workability and hardenability throughout the year, three types are required for summer, spring and fall, and winter in consideration of the work temperature range in each season. In addition, the durability must be sufficient even if the composition is changed.

Regarding the cured sealing material, first,
Surface gloss must be adequate. In other words, if the gloss is too large, the joint becomes conspicuous when there is a slight defect on the surface of the sealing material, for example, mixing of air bubbles, a resulting surface crater phenomenon, and poor finish, so that the defect becomes clear. Also, in recent years, exterior wall materials that have been painted in a matte color have become widespread, and in that case, a high gloss is not desirable in terms of design.

[0013] The durability must be evaluated with emphasis on actual construction at the joint. Among the conventional proposals for building sealing materials, the weather meter test on a sheet-shaped sample that has been sufficiently cured in a room or a sample applied on a board, which has been proposed as an evaluation method, is a guide for material deterioration. Even so, it is not possible to evaluate the effect of direct sunlight at the stage of insufficient curing immediately after construction.

Further, in addition to the above-mentioned shrinkage, the siding board particularly frequently undergoes thermal expansion and contraction (referred to as a movement) especially in the case of the outer wall. Receive from the state,
The stress cracking durability at this time cannot be predicted. In short, there is no crack rupture and peeling from building materials as a sealing material actually applied, and the original watertightness,
It must be a proposal to maintain airtightness over a long period of time. An object of the present invention is to provide a modified silicone-based sealing material suitable for joints used for siding board wall materials in consideration of the above points.

[0015]

Means for Solving the Problems (A) A rubber system 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) 5 to 20 parts by weight of epoxy resin, (C) 3 to 7 parts by weight of air-curable substance, (D) 4 to 8 parts of photo-curable resin, based on 100 parts by weight of organic polymer.
Parts by weight, (E) benzotriazole-based ultraviolet absorber
4 to 0.8 parts by weight, (F) 1.0 to 1.5 parts by weight of a hindered phenolic antioxidant, (G) 75 to 90 parts by weight of a phthalate plasticizer, (H) a filler 240 to 27
0 parts by weight, (I) 10 to 15 parts by weight of an anti-sagging reinforcing agent,
(J) A modified silicone-based sealing material composition for siding board wall materials, comprising 1-2 parts by weight of a tetravalent tin compound and (K) 7-10 parts by weight of epoxysilane.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the rubber 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 following are examples. The number average molecular weight of the polymer is preferably from 3,000 to 30,000, more preferably from 15,000 to 20,000,
The ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) is
Those having a molecular weight distribution of 1.6 or less and having a narrow molecular weight distribution are preferable, and are generally called modified silicone resins.
As another component, a low molecular weight compound having a reactive silicone functional group may be included for controlling the cross-linking property and physical properties of the cured product. As an example of these, "Exester" (produced by Asahi Glass Co., Ltd.), which is already industrially produced, can be used.

The epoxy resin (B) is used for improving the adhesion to the metal constituting the joint and the paint surface.
Particularly, the adhesiveness from immediately after application to a semi-cured state is improved.
The epoxy resin is not particularly limited as long as it contains at least one epoxy group, and a commonly used epoxy resin can be used. For example, epoxy resins that can be used in the present invention include epichlorohydrin-bisphenol A epoxy resin, epichlorohydrin-bisphenol F epoxy resin, novolak epoxy resin, hydrogenated bisphenol A epoxy resin, and bisphenol A propylene oxide adduct. Glycidyl ether type epoxy resin, urethane modified epoxy resin and the like.

The compounding amount is 5 to 20 parts by weight based on 100 parts by weight of the polymer (A). If the amount is too large, the elasticity of the architectural sealing material is lost, and if the amount is too small, the effect of improving the adhesiveness is small. The curing agent for the epoxy resin can be used in consideration of the curability of the entire composition.

The air-curable substance (C) is a compound having in its molecule an unsaturated group which is polymerized by oxygen in the air, and preferentially cures the surface layer in the initial stage of insufficient curing of the sealing material. Used to reduce initial tack and prevent dust from adhering. Specific examples include the following compounds.

Drying oils such as paulownia oil, linseed oil, eno oil, soybean oil, sunflower oil, and rapeseed oil; various alkyd resins obtained by modifying the drying oil; reaction products of the drying oil with the functional polyoxyalkylene; Reaction products (urethane oil) of a drying oil and an isocyanate compound, acrylic polymers modified with the drying oil, epoxy resins, silicone resins, butadiene, chloroprene, isoprene, 1,3-pentadiene, etc. Liquid polymer obtained by homopolymerizing or copolymerizing the diene compound of No. 8, NBR obtained by copolymerizing a monomer such as acrylonitrile or styrene having copolymerizability with the diene compound so that the diene compound becomes the main component. , SBR and the like, and various modified products thereof (maleated modified product, boiled oil modified product, etc.).

Of these, drying oils, liquid diene polymers and modified products thereof are particularly preferred. They are,
They may be used alone or in combination of two or more. In some cases, the effect may be enhanced by using a catalyst or a metal dryer that promotes the oxidative curing reaction together with the air-curable substance. Examples of these catalysts and metal dryers include metal salts such as zirconium octylate and amine compounds.

The amount of the air-curable substance used is 3 to 7 parts by weight based on 100 parts by weight of the polymer (A). If the amount is less than 3 parts by weight, the effect of improving the initial tack is insufficient and dust tends to adhere. At the construction site, there is a lot of dust, and in addition to the scattered matter in the air, there is a part that adheres to the wall and flows by rainwater and is carried on the surface. In addition, three parts are required to prevent the adhesion of fiber debris when the clothes of the worker come into contact during various construction works. If the amount is too large, elongation as a sealing material is impaired, and discoloration is caused by long-term outdoor exposure, and cracks are easily generated.

The photocurable resin (D) is used for improving the surface tack after curing of the sealing material and reducing the adhesion of dust. The improvement rate of the surface tack is slower than that of the air-curable substance of (D), but the long-term weather resistance is stable and does not change color as in (D). The photocurable compound is
A compound that undergoes a chemical change in its molecular structure by the action of light and cures. Specific examples include compounds represented by unsaturated acrylic compounds, polyvinyl cinnamates, azide resins, etc., and unsaturated acrylic resins are preferred.

The unsaturated acrylic compound is preferably a monomer or oligomer having one or several acryloyl groups or methacryloyl groups, or a mixture thereof.
Particularly, a compound having an acryloyl group is preferable.

The compounding amount of the photocurable compound is 4 to 8 parts by weight with respect to 100 parts by weight of the polymer of (A). If it exceeds the part, cracks are likely to occur in a long-term durability test.

Specific examples of the benzotriazole ultraviolet absorber (E) include tinuvin P, tinuvin 234,
Tinuvin 320, Tinuvin 326, Tinuvin 327 (all manufactured by Ciba Specialty Chemicals Co., Ltd.)
Can be exemplified. As the compounding amount, the polymer (A) 100
Use 0.4 to 0.8 parts by weight with respect to parts by weight. If the amount is too large, the effect is not improved and the economic efficiency is reduced.

Specific examples of the hindered phenolic antioxidant (F) include Nocrack 200, Nocrack M-17, Nocrack SP, Nocrack SP-N, Nocrack NS-5, Nocrack NS-6 and Nocrack NS.
-30, Nocrack 300, Nocrack NS-7, Nocrack DAH (all manufactured by Ouchi Shinko Chemical Co., Ltd.); Irganox 245, Irganox 259,
Ilganox 565 (manufactured by Ciba Specialty Chemicals Co., Ltd.) can be exemplified. (A)
1.0 to 1.5 parts by weight based on 100 parts by weight of the polymer. If too much, the economics will be reduced.

Examples of the phthalate plasticizer (G) include dioctyl phthalate (DOP), dibutyl phthalate (DBP), and butylbenzyl phthalate (B
BP) or the like is used to enhance the mixing workability of the composition and adjust the composition to a suitable elastic body. If necessary, other ester-based plasticizers such as dioctyl adipate are used in combination, but it is economical to use inexpensive DOP which is mass-produced, modified silicone resin and other compounding agents. Is compatible and suitable. As the compounding amount, the polymer 1 of (A)
75 to 90 parts by weight per 100 parts by weight. Since the number of plasticizers is closely related to the workability of the construction, it is necessary to increase the number of plasticizers provided in winter within this range and to reduce the number in summer.

The filler of (H) is not limited to a specific filler. Specific examples thereof include reinforcing fillers such as fume silica, precipitated silica, silicic anhydride, hydrous silicic acid and carbon black; calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, Organic bentonite, ferric oxide, zinc oxide, activated zinc white and polyvinyl chloride,
Fillers such as organic fillers such as polyolefin; inorganic balloons such as glass balloon, shirasu balloon, Saran balloon, and phenol balloon, and organic balloons.

The fillers may be used alone or in combination of two or more. The filler is
The filler is not limited to a specific filler as described above, and may be selected according to the expected characteristics of the composition. It is desirable in terms of control and physical properties of the cured product. The compounding amount is 240 to 270 parts by weight based on 100 parts by weight of the polymer (A). If the amount is too small, the viscosity is too low to be applied to vertical joints, causing sagging. If the amount is too large, the viscosity becomes high and the workability is deteriorated, and the elasticity after curing is adversely affected.

As the anti-sagging reinforcing agent (I), hydrogenated castor oil and organic bentonite are used in an amount of 10 to 15 with respect to (A).
The use of parts by weight reinforces the sagging prevention effect of the filler. In the summer, sagging is likely to occur, so it is necessary to add a large amount.
However, if the amount is too large, the dispersibility at the time of mixing, the sucking property to a caulking gun, and the surface finish are deteriorated.

Examples of the tetravalent tin compound (J) include dibutyltin phthalate, dibutyltin laurate, dibutyltin maleate, dibutyltin diacetate, dibutyltin diacetacetonate, and tin alcohol acetylacetone, and are used as catalysts. . The tetravalent tin compound imparts appropriate curing characteristics in the composition system of the present invention over other catalysts and finishes the sealing material after curing more easily. The compounding amount is 1 to 2 parts by weight based on 100 parts by weight of the polymer (A).

The epoxysilane (K) is a compound having a silicon atom to which a hydrolyzable alkoxy group is bonded and an epoxy group, and is γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane. ,
γ-glycidoxypropylmethyldimethoxysilane, β
-(3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like. A-186, A-
187 (manufactured by Nippon Unicar).

Epoxysilane enhances the affinity between the filler and the silicone resin and suppresses a decrease in elongation of the cured product due to the filler. Further, the siding board strengthens the adhesive strength of the sealing material to the joint interface when the siding board starts contracting, and acts to prevent the occurrence of peeling. As the compounding amount,
(A) 7 to 15 parts by weight per 100 parts by weight. If the amount is too large, the elongation of the cured product is reduced. As other compounds of the present invention, other types of catalysts, curing accelerators, dyes / pigments, small amounts of organic solvents, and the like can be used as required.

All of the above (A) to (K) may be mixed and stored, but usually the catalyst-based compound is divided and stored as a two-component building sealing material. Mix and use before construction.

[0036]

Next, the present invention will be specifically described based on examples of the sealing material of the present invention. (Examples and Comparative Examples) Table 1 shows the composition.

[0037]

[Table 1]

The composition shown in Table 1 was divided into a base and a curing agent composition, and the composition was prepared as a two-component system (base: curing agent = 10: 1). The base material is a modified silicone resin (Exastar S2410 manufactured by Asahi Glass Co., Ltd.), a compounding agent such as a plasticizer and a filler.
After throwing into a 00L butterfly mixer and mixing, the dispersibility was improved with three rolls. Separately, a curing catalyst, a plasticizer, and a filler were mixed to obtain a curing agent.

The base and the curing agent produced by the above method were mixed, and the following tests (1) to (8) were performed. Table 2 shows the composition after mixing and the results for each of the examples and comparative examples.

[0040]

[Table 2]

(1) Viscosity of the composition: The viscosity of the No. 7 rotor at 10 rpm was measured at each temperature using a B8R rotational viscometer. The viscosity is suitably from 3,000 to 3,500 poise, and if it exceeds 4,000 poise, workability is impaired.

(2) Pot life: The time until the viscosity of the mixture doubled was defined as the pot life, and measured at each temperature.
Need more than 5 hours.

(3) Possible finishing time: After storing the blended product mixed in the prescribed blending for one hour in a closed container, it is determined at each temperature for 3 hours.
It was applied on a flat plate in the form of a sheet having a thickness of 1 mm, and the surface finish time with a spatula was measured. Need more than 2 hours.

(4) Curing time: According to the penetration test method of JIS K 2207, the time until the penetration reached 50 or less was defined as the curing time, and measured at each temperature.

(5) Workability, slip and surface tack: Vertical joints (joint width 30 mm) made of aluminum building material on both sides and siding boards (manufactured by Daiken Kogyo Co., Ltd.) on both sides at the construction site , A joint depth of 12 mm) was filled with a sealing material without a backup material every season using a caulking gun, and the condition until hardening was observed. The test started on a sunny sunny surface. The evaluation was performed based on the following. Construction workability: The mixture is sucked up using a caulking gun, and when it is applied to joints, the workability of gunning, gunning workability,
The spatula finishing workability was comprehensively evaluated. …: Easy to work overall and good. ×: There are drawbacks such as heavy suction, heavy gun strike, and inability to finish smoothly. △… Between ○ and △. Slip: judged 3 days after construction. ○: None, △: Slip slightly, ×: Slip large. Tack: judged 7 days after construction. ○: small tack, good; △: slight tack, ×: large tack.

(6) Gloss: Measured with a portable gloss meter (manufactured by BYK Japan KK) at an incident angle of 60 °.

(7) Weather resistance test: The composition was coated with a thickness of 20 mm.
After curing at 20 ° C. for 14 days, the state of deterioration after irradiation for a predetermined time was observed with a sunshine weather meter (WOM Suga Test Machine Co., Ltd.). …: Good, △: minute cracks generated, slightly discolored, ×: cracks generated, discolored.

(8) Outdoor exposure test: 3,000 × 450
Two siding boards of × 12 mm are stuck together so that a joint having a width of 10 mm is formed in the gap. Fix the outside edge of the siding board with screws,
The lower end is fixed with a hook. The siding board changes its dimensions due to environmental conditions such as direct sunlight, climate, wind and rain, and deforms the sample as joint expansion and contraction. In particular, it tends to gradually shrink immediately after construction. In the construction, first, a polyethylene tape for preventing adhesion on three sides was applied to the joint bottom, and then a primer (Hybon primer NEW80, manufactured by Hitachi Chemical Co., Ltd.) was applied to the adhesive surface. Thereafter, a sealing material was cast. The test started each season. Although the degree of deformation received by the sample differs depending on the start time, in this test, joint expansion after half a year was 30% at maximum, and daily expansion and contraction was ± 8%. The exposure was tested at 60 ° on the south side for one year, and then evaluated from a practical point of view for the occurrence of peeling and cracking. The results are shown with the peeling added as in the previous section.

[0049]

As described above, the sealing material of the present invention, by specifying the blending amounts of the respective blending components, can improve the workability, hardenability, and siding board wall joint at the actual construction site. Excellent in overall characteristics such as durability.

[0050]

[Brief description of the drawings]

FIG. 1 Schematic of the exposure test

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Siding board 2 ... Sealing material 3 ... Polyethylene tape 4 ... Mounting hook 5 ... Stand 6 ... Screw

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) C09K 3/10 C09K 3/10 L 15/08 15/08 F term (reference) 2E110 AA26 AA42 AA57 AB22 BA12 CA03 DA03 DA10 DD03 GA33W GA43Z GA44Z GB18Z GB32Z GB46Z GB49Z GB53Z GB54Z 4H017 AA03 AA24 AA27 AA31 AA35 AB08 AB15 AC07 AC08 AC11 AD05 AE03 4H025 AA15 AA18 AA55 4J002 AE001 FD03 FP09 AE03 AE03 AE03 AE03 AE05 AE03

Claims (1)

[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 capable of crosslinking by forming a siloxane bond. (B) 5 to 20 parts by weight of an epoxy resin, (C) 3 to 3 parts by weight of an air-curable substance,
7 parts by weight, (D) 4 to 8 parts by weight of a photocurable resin, (E) 0.4 to 0.8 parts by weight of a benzotriazole-based ultraviolet absorber, (F) 1.0 to 1.0 parts of a hindered phenolic antioxidant
1.5 parts by weight, (G) phthalate plasticizer 75 to
90 parts by weight, (H) 240 to 270 parts by weight of filler,
(I) 10 to 15 parts by weight of an anti-sagging reinforcing agent, (J) 1-2 parts by weight of a tetravalent tin compound, (K) epoxy silane 7 to 10
Modified silicone-based sealing material composition for siding board wall material, comprising parts by weight.