JPH06340739A - Silylated polyester and sealing material containing the same - Google Patents

Abstract

PURPOSE:To obtain a silylated polyether, containing both terminals having a specific structure and connected to a main chain which is a copolymer of tetrahydrofuran and ethylene oxide with a specified connecting group, excellent in room-temperature curability, mechanical characteristics, etc., and useful as a sealing material. CONSTITUTION:The silylated polyester contains (A) both terminals having a structure expressed by formula I (R1, R2 and R3 are hydrolyzable group or alkyl, with the proviso that at least two of R1, R2 and R3 are hydrolyzable group), (B) a copolymer of tetrahydrofuran and ethylene oxide (with the proviso that the number of mol of tetrahydrofuran residue is 15-85% based on the total number of mol of the tetrahydrofuran residue and ethylene oxide residue) as a main chain and (C) the main chains and/or the main chain and the terminal group mutually connected with a connecting group expressed by formula II (Ra is aliphatic or aromatic group). The number-average molecular weight of this compound is 500-50000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel silylated polyether and a room temperature-curable sealing material containing the same as an active ingredient, and more particularly to a sealing material which is cured into a rubber-like elastic body by moisture.

[0002]

BACKGROUND OF THE INVENTION Several room temperature curable resin compositions have been developed for use as sealing materials. For example, JP-A-54-6097 discloses a composition of a silyl group terminated polyether (alkylene oxide polymer) or polyester, and JP-B-61-18582 discloses a composition having a silyl group terminal. Propylene oxide polymers are disclosed. However, a sealing material having a good balance of mechanical properties, weather resistance, heat resistance, etc. after curing has not yet been known. In JP 3-100048 A and JP 3-100049 A, it is said that a rubber-like elastic body having excellent properties can be obtained by suppressing the crystallinity of polyoxytetramethylene with a special solvent. Has a drawback that it does not become a rubber-like elastic body at a low temperature because it only lowers the melting point.

The first object of the present invention is to provide novel silylated polyethers. The present invention is the second
In addition, it is an object of the present invention to provide a room temperature curable sealing material which gives a cured product excellent in mechanical properties, weather resistance, heat resistance and the like.

[0004]

That is, the first aspect of the present invention is
In addition, (1) both ends have the following formula (Formula 3):

[0005]

[Chemical 3] (Here, R ¹ , R ² and R ³ each independently represent a hydrolyzable group or an alkyl group, provided that R ¹ , R ^{2 and}
And at least two of R ³ are hydrolyzable groups), (2) the main chain is a copolymer of tetrahydrofuran and ethylene oxide, and the number of moles of the tetrahydrofuran residue is tetrahydrofuran residue. 15 to the total number of moles of groups and ethylene oxide residues
85%, and (3) between the main chains and / or between the main chain and the terminal group is (Chemical formula 4):

[0006]

[Chemical 4] (Wherein R _a represents a linear or branched aliphatic group or aromatic group), and
(4) A silylated polyether having a number average molecular weight of 500 to 50,000.

The silylated polyether of the present invention is characterized by having the above-mentioned structure. In particular, it is important that the main chain is a copolymer of tetrahydrofuran and ethylene oxide in a specific ratio. The main chain copolymer part is
It may be an arbitrary copolymer such as a random copolymer or a block copolymer. The ratio of the tetrahydrofuran residue and the ethylene oxide residue in the above copolymer is such that the tetrahydrofuran residue is 15 with respect to the total number of moles of both.
~ 85%, preferably 20-80%. If there are too many tetrahydrofuran residues, there will be a melting point, and if there are too many ethylene oxide residues, the mechanical strength of the cured product will be poor,
And there is a melting point. The main chain of the above-mentioned copolymer is bound to the main chain or the terminal group by the above-mentioned connecting group. When R _a is a straight-chain or branched aliphatic group in the linking group, examples thereof include an alkylene group having 1 to 20 carbon atoms, a cycloalkylene group, and an alkenylene group. Preferred is an alkylene group having 1 to 12 carbon atoms. Also,
When R _a is an aromatic group, examples thereof include a phenylene group which may be substituted with a methyl group, an ethyl group or the like. Preferred examples of the linking group are an aliphatic dicarboxylic acid residue such as sebacic acid, adipic acid and succinic acid, and an aromatic dicarboxylic acid residue such as terephthalic acid. The method for introducing each linking group will be described later. The number of linking groups is preferably 2 to 50 in one molecule of the silylated polyether.

Next, the terminal silyl group (I) will be described. When R ¹ , R ² or R ³ is a hydrolyzable group, it is a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amide group, an acid amide group, an aminooxy group, a mercapto group or the like. be able to. As the hydrolyzable group, an alkoxy group is particularly preferable, and a methoxy group is more preferable. When it is an alkyl group, it preferably has 1 to 8 carbon atoms, and may be linear or branched. For example, it may be a methyl group, an ethyl group, a propyl group, a butyl group or the like.

The number average molecular weight of the silylated polyether of the present invention is 500 to 50,000, preferably 2,0.
It is 00-35,000.

When exposed to the atmosphere, the silylated polyether of the present invention forms a three-dimensional network structure by the action of water and hardens into a solid having rubber-like elasticity. The curing rate varies depending on the ambient temperature, the relative humidity and the type of hydrolyzable group.

The silylated polyether of the present invention can be basically produced according to a known method such as the method described in JP-A-54-6097. For example, first, a polyether having a hydroxyl group at both ends (copolymer of tetrahydrofuran and ethylene oxide) is produced by a conventional method. Then, the terminal of this copolymer is allylated. Examples of the allylation method include reacting with a dicarboxylic acid (for example, sebacic acid, adipic acid, succinic acid, etc.) halide to convert the terminal to —C (═O) Z (where Z is a halogen atom), Next, a method of introducing an allyl group through an ester bond by reacting with an allyl compound capable of reacting with this group can be mentioned. Next, at the allyl terminal of the polyether, the following formula (Formula 5):

[0012]

[Chemical 5] The silicon hydride compound represented by (R ¹ , R ² and R ³ are as defined above) is subjected to an addition reaction using a platinum catalyst (for example, a solution of chloroplatinic acid in isopropyl alcohol). Examples of usable silicon hydride compounds include halogenated silanes such as trichlorosilane and methyldichlorosilane; alkoxysilanes such as trimethoxysilane, triethoxysilane, methyldiethoxysilane and dimethoxymethylsilane; methyldiacetoxysilane and the like. Acyloxysilanes; ketoxymate silanes such as bis (dimethylketoximate) methylsilane; and the like.
The silicon halide-terminated polymer obtained when the halogenated silanes are reacted is hydrolyzed by moisture when exposed to the air and rapidly cured at room temperature.
Generates hydrogen chloride. To avoid this, the halogen functional group may be further converted into another hydrolyzable group after the hydrosilylation reaction. Examples of the hydrolyzable group that can be converted include an alkoxy group, an acyloxy group, a ketoximate group, an amide group, an acid amide group, an aminooxy group, and a mercapto group. There are various methods for converting the halogen functional group into these hydrolyzable groups. For example, when converting to an alkoxy group, alcohols such as methanol and ethanol; alkoxides such as sodium, potassium and lithium of alcohols; orthoformate esters such as methyl orthoformate and ethyl orthoformate; ethylene oxide, propylene oxide and allylglycidyl Epoxy compounds such as ether; etc. are reacted with halogen functional groups. When converting to an acyloxy group, carboxylic acids such as acetic acid and propionic acid; when converting to an aminooxy group, hydroxylamines such as N, N-dimethylhydroxylamine and N, N-diethylhydroxylamine. When converting to an amide group,
When converting primary and secondary amines such as N, N-dimethylamine, N, N-diethylamine and pyrrolidine into acid amide groups, at least one hydrogen atom on the nitrogen atom such as acetamide and formamide Acid amides having ;; when converting to a ketoximate group, ketoximes such as acetoxime and methylethylketoxime; when converting to a mercapto group, mercaptans such as n-octylmercaptan and t-butylmercaptan, Each is reacted with a halogen functional group. You may use combining these methods. Further, such a method is possible not only in the case of a halogen functional group but also in converting another hydrolyzable functional group into another hydrolyzable functional group.

When the raw material copolymer (polyether) has a relatively low molecular weight, it can be used by increasing the molecular weight. When the molecular weight is increased, the above-mentioned linking group is introduced between the main chains. For example, the terminal hydroxyl group of the main chain copolymer, for example, an aliphatic dicarboxylic acid (for example, sebacic acid,
Adipic acid, succinic acid, etc.) or aromatic dicarboxylic acid (eg, terephthalic acid, etc.), polycondensation with a halide, etc. (introduction of ester bond) can be used.

Thus, the raw material polyether has an increased molecular weight, and the main chain polyether has an ester bond connecting group introduced therein.

Secondly, the present invention provides a room temperature curable sealant containing the above-mentioned novel silylated polyether as an active ingredient.

In the sealing material of the present invention, in order to control the physical properties such as strength and elongation of the cured product of the silylated polyether, at least two Y groups in one molecule (Y group is bonded to silicon atom). It has a halogen atom, a hydrogen atom, a hydroxy group, an alkoxy group, an acyloxy group, a ketoximate group, an amide group, an acid amide group, an aminooxy group, and a mercapto group) and has 1 to 10 silicon atoms. It can contain 20 silicon compounds. As the Y group, a hydroxy group and an alkoxy group are particularly preferable.
Specific examples of the silicon compound include a commercially available silane coupling agent, a linear, branched, reticulated or cyclic organopolysiloxane compound, and the like. These may be used alone or in combination of two or more. Can be used. The silicon compound is preferably used in an amount of 0 to 20 parts by weight, particularly 0 to 10 parts by weight, based on 100 parts by weight of the silylated polyether.

In the sealing material of the present invention, a silanol condensation catalyst can be used for curing the silylated polyether, but it is not necessary to use it. As silanol condensation catalysts, alkyl titanates; organosilicon titanates; tin octylate; metal salts of carboxylic acids such as dibutyltin laurate and dibutyltin maleate, dibutyltin phthalate; dibutylamine-2-ethylhexoate, etc. The known silanol condensation catalysts such as amine salts of the above; and other acidic catalysts and basic catalysts can be effectively used. These silanol condensation catalysts are used in an amount of 0 to 10% by weight based on the silylated polyether.
Is preferably used in an amount of. When the hydrolyzable group in the terminal group of the silylated polyether is an alkoxy group, silanol condensation catalyst is preferably used because the silylated polyether alone has a slow curing rate. In this case, as the silanol condensation catalyst, a tin carboxylate or a system in which active zinc white is combined with a tin carboxylate is particularly preferable.

In the sealing material of the present invention, the silylated polyether which is the active ingredient can be modified by mixing various fillers. Examples of the filler include reinforcing fillers such as fumed 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,
Fillers such as ferric oxide, zinc oxide, activated zinc oxide, hydrogenated castor oil and silas balloons; fibrous fillers such as asbestos, glass fibers and filaments can be used. When it is desired to obtain a cured composition having high strength with these fillers, mainly fumed silica, precipitated silica, silicic anhydride,
If a filler selected from hydrous silicic acid, carbon black, surface-treated fine calcium carbonate, calcined clay, clay and activated zinc white is used in an amount of 1 to 700 parts by weight based on 100 parts by weight of silylated polyether, Good results are obtained. Further, when it is desired to obtain a cured composition having low strength and large elongation, titanium oxide, calcium carbonate,
When a filler selected from magnesium carbonate, talc, ferric oxide, zinc oxide and silas balloon is used in an amount of 5 to 500 parts by weight based on 100 parts by weight of silylated polyether, preferable results are obtained. Of course, these fillers may be used alone or in combination of two or more.

In the present invention, it is more effective to use a plasticizer in combination with the above-mentioned filler, since the elongation of the cured product can be increased and a large amount of the filler can be mixed. As such a plasticizer, a conventional one can be used, for example, phthalic acid esters such as dioctyl phthalate, dibutyl phthalate and butylbenzyl phthalate; aliphatic dibasic acid such as dioctyl adipate, isodecyl succinate and dibutyl sebacate. Esters; glycol esters such as diethylene glycol dibenzoate and pentaerythritol ester; aliphatic esters such as butyl oleate and methyl acetylricinoleate; phosphate esters such as tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate; Epoxidized soybean oil,
Epoxy plasticizers such as epoxy benzyl stearate; plasticizers such as chlorinated paraffins, alone or in combination with 2
It can be optionally used in the form of a mixture of more than one kind. The amount of the plasticizer is 0 to 4 with respect to 100 parts by weight of the silylated polyether.
An amount of 00 parts by weight is preferred.

The sealant of the present invention mainly contains the above-mentioned filler, plasticizer and condensation catalyst in many cases, but an adhesion promoter such as a phenol resin and an epoxy resin, a pigment, an antiaging agent, an ultraviolet absorber. Additives such as can also be included in any amount.

The sealing material of the present invention can be either a one-liquid sealing material or a two-liquid sealing material. When used as a two-part sealant, for example, it is divided into a first component consisting of silylated polyether, a filler and a plasticizer, and a second component consisting of a filler, a plasticizer and a silanol condensation catalyst, and used. Good results are obtained if both components are mixed and used immediately before. When used as a one-part sealant, the silylated polyether, filler, plasticizer and silanol condensation catalyst should be thoroughly dehydrated and dried, then mixed in the absence of water and stored in a cartridge or the like. It can also be used as a one-component sealing material with good storage stability.

The sealing material of the present invention is used for buildings, ships,
It can be used as a sealant for automobiles and roads. further,
Glass, porcelain, alone or with the help of a primer,
Since it can be adhered to a wide range of substrates such as wood, metal and resin moldings, it can be used as various types of sealing and adhesion sealing materials.

[0023]

The present invention will be described in more detail by the following examples. The both-end hydroxyl group type tetrahydrofuran-ethylene oxide copolymers used in the following examples were prepared as follows: That is, each monomer of tetrahydrofuran and ethylene oxide was polymerized in the presence of an acid catalyst by a conventional method. Then, copolymers having various ethylene oxide contents shown in Table 1 were obtained. The ethylene oxide content was determined by measuring the nuclear magnetic resonance ( ¹ H-NMR) spectrum of the copolymer. Example 1 In a 1 liter three-necked flask equipped with a dropping funnel, a reflux condenser and a stirrer, 47.8 g of sebacic acid dichloride was added.
(0.200 mol) and 100 ml of dry toluene were charged. 200 g of tetrahydrofuran having a number average molecular weight of 1250 and hydroxyl group-terminated tetrahydrofuran-ethylene oxide copolymer (ethylene oxide content 34 mol%), pyridine 38.0 g (0.480 mol)
And 210 ml of dry toluene were added dropwise at room temperature over 3 hours under a nitrogen stream. Then, it heated up at 50 degreeC and heated for 1.5 hours. Next, allyl alcohol 9.
30 g (0.160 mol) and pyridine 12.7 g
(0.161 mol) was added and the mixture was stirred at 50 ° C. for 2.5 hours. The salt was removed from the reaction mixture by washing with water, and then the reaction mixture (organic layer) was dried over magnesium sulfate.
Then, the volatile components were distilled off under reduced pressure to obtain 216 g of a colorless transparent liquid polymer, allylated polyether.

500 m with reflux condenser and stirrer
in a 3-neck flask of 1 l, the above allylated polyether 8
1.9 g, dry toluene 80 ml, dimethoxymethylsilane 5.0 g (0.047 mol) and isopropyl alcohol solution of chloroplatinic acid (0.0436 g as platinum)
/ Ml) 21 μl was charged and the mixture was stirred at 100 ° C. for 7 hours under a nitrogen stream. The volatile components were distilled off under reduced pressure to obtain 84.4 g of colorless and transparent silylated polyether at both ends. The number average molecular weight and the weight average molecular weight determined by gas chromatography in terms of polystyrene were 5,500 and 20,000, respectively. Further, from the thermal analysis, the glass transition temperature and the melting point are −80 ° C. and −5.
It was 8 ° C. The results of infrared absorption (IR) spectrum and nuclear magnetic resonance ( ¹ H-NMR) spectrum analysis are shown in FIGS. 1 and 2, respectively.

The silylated polyether 10 obtained above
250 parts by weight of fatty acid-treated colloidal calcium carbonate 250
Parts by weight, dibutyl phthalate 150 parts by weight, dibutyltin dilaurate 5 parts by weight and laurylamine 1.3 parts by weight are added, mixed thoroughly with three paint rolls and poured onto a glass plate at 60 ° C. in the atmosphere. After standing for 24 hours, a sheet-like rubber-like elastic body having a thickness of about 3 mm was obtained. Thermal analysis of this cured product revealed that the glass transition temperature was -84 ° C, there was no melting point, and the crystallinity was lost. Also, J
According to IS K 6301, a tensile test of a No. 2 dumbbell-shaped test piece showed a tensile strength of 9.2 kg.
The f / cm ² and the elongation were 530%. Example 2 The number average molecular weight of 1
A both-end silylated polyether was produced in the same manner as in Example 1 except that 300 of both-end hydroxyl group type tetrahydrofuran-ethylene oxide copolymer (ethylene oxide content: 78 mol%) was used. The number average molecular weight and the weight average molecular weight determined by gas chromatography in terms of polystyrene are 5,800 and 20,00, respectively.
It was 0. Further, from the thermal analysis, the glass transition temperature and the melting point were −80 ° C. and 1.2 ° C., respectively.

An additive was added to the above-mentioned silylated polyether in exactly the same formulation as in Example 1, and the same treatment as in Example 1 was carried out to obtain a sheet-like rubbery elastic body having a thickness of about 3 mm. It was According to thermal analysis, the glass transition temperature of this cured product is -82 ° C.
So there was no melting point. The tensile strength is 6.9 kgf /
cm ² and the elongation was 380%. Examples 3 to 4 Both ends hydroxyl group type polyether was replaced with both ends hydroxyl group type tetrahydrofuran-ethylene oxide copolymer having the composition ratio shown in Table 1 in the same manner as in Example 1 except that both ends silylated. A polyether was produced. Table 1 shows each physical property value measured in the same manner as in Example 1. Also,
Table 1 also shows the physical property values measured for the sheet-like rubber-like elastic body having a thickness of about 3 mm obtained by adding the additives in exactly the same formulation as in Example 1 and treating in the same manner as in Example 1. Comparative Example 1 60.9 g of sebacic acid dichloride was placed in a 1-liter three-necked flask equipped with a dropping funnel, a reflux condenser and a stirrer.
(0.255 mol) and 250 ml of dry toluene were charged. Here, a mixture of 201 g of a both-end hydroxyl group type tetrahydrofuran homopolymer having a number average molecular weight of 1000 azeotropically dehydrated with toluene, 40.8 g (0.516 mol) of pyridine and 200 ml of dry toluene was added under a nitrogen stream.
It was added dropwise at room temperature over 4 hours. After stirring and aging for 2 hours as it was, 12.5 g (0.215 mol) of allyl alcohol and 17.0 g (0.215 mol) of pyridine were added, and the mixture was further stirred for 2 hours. The salt was removed by filtration, and the volatile components were distilled off under reduced pressure to obtain 238 g of a colorless transparent liquid polymer (allylated polytetrahydrofuran).

500 m equipped with reflux condenser and stirrer
Into a 1-liter three-necked flask, 153 g of the above allylated polytetrahydrofuran, 150 ml of dry toluene, 8.24 g (0.0776 mol) of dimethoxymethylsilane and 35 μl of an isopropyl alcohol solution of chloroplatinic acid (0.0436 g / ml as platinum) were charged. Then, the mixture was stirred under a nitrogen stream at 100 ° C. for 7 hours. Evaporate the volatile components under reduced pressure,
156 g of colorless and transparent silylated polyether at both ends was obtained. The number average molecular weight and the weight average molecular weight determined by gas chromatography in terms of polystyrene were 10,000 and 23,000, respectively. Also,
From the thermal analysis, the glass transition temperature and the melting point are −
80 ° C and 19 ° C.

An additive was added to the silylated polyether obtained above in exactly the same formulation as in Example 1 and treated in the same manner as in Example 1 to give a sheet-like rubber-like elasticity having a thickness of about 3 mm. Got the body According to thermal analysis, this cured product had a glass transition temperature of -85 ° C and a melting point of -1.3 ° C. The tensile strength at room temperature was 11 kgf / cm ² and the elongation was 300%, but it was hard and plastically deformed at 0 ° C or lower. Comparative Example 2 The same procedure as in Comparative Example 1 was repeated except that 201 g of the both-end hydroxyl group type polyethylene glycol having a number average molecular weight of 1100 was used in place of the both-end hydroxyl group type tetrahydrofuran homopolymer of Comparative Example 1. An ether was produced. The number average molecular weight and the weight average molecular weight, which were determined by gas chromatography in terms of polystyrene, were 9,500 and 32,000, respectively. Also,
Thermal analysis shows a glass transition temperature of -81 ° C and a melting point of 58 ° C.
Met.

An additive was added to the silylated polyether obtained above in exactly the same formulation as in Example 1, and the same treatment as in Example 1 was carried out to obtain a sheet-like rubber-like elasticity having a thickness of about 3 mm. Got the body According to thermal analysis, this cured product had a glass transition temperature of -83 ° C and a melting point of 24 ° C. The tensile strength was 5.1 kgf / cm ² and the elongation was 120%.

[0030]

[Table 1] Example 5 212 g of allylated polyether was produced in exactly the same manner as in Example 1 except that adipic acid dichloride was used instead of sebacic acid dichloride.

500 m with reflux condenser and stirrer
in a 3-neck flask of 1 l.
0 g, dry toluene 100 ml, dimethoxymethylsilane 6.2 g (0.058 mol) and chloroplatinic acid in isopropyl alcohol (0.0436 g / platinum /
(25 ml) was charged, and the mixture was stirred under a nitrogen stream at 100 ° C. for 7 hours. The volatile component was distilled off under reduced pressure to obtain 103 g of a colorless and transparent silylated polyether having both ends. The number average molecular weight and the weight average molecular weight determined by gas chromatography in terms of polystyrene were 6,100 and 16,000, respectively. Further, from the thermal analysis, the glass transition temperature and the melting point are -82 ° C and -1.2 ° C, respectively.
Met.

An additive was added to the silylated polyether obtained above in exactly the same formulation as in Example 1, and the same treatment as in Example 1 was carried out to give a sheet-like rubber-like elasticity having a thickness of about 3 mm. Got the body Thermal analysis revealed that the cured product had a glass transition temperature of -83 ° C and no melting point. The tensile strength is 11k.
The gf / cm ² and the elongation were 480%. Test Example To 100 parts by weight of the silylated polyether obtained in Example 1, Comparative Example 1 and Comparative Example 2, 1 part by weight of dibutyltin dilaurate and 0.25 part by weight of laurylamine were added and mixed well. Pour it on a glass plate and put it in the air 60
After leaving it at 24 ° C. for 24 hours, a transparent sheet having a thickness of about 3 mm was obtained.

The obtained sheet was continuously irradiated with a carbon arc of a sunshine weather meter (63 ° C., 30% RH) to trace the change in surface appearance. 40
The appearance after the lapse of time was as follows.

Example 1: Almost no change Comparative Example 1: Wrinkled surface Comparative Example 2: Surface liquefied

[0035]

According to the present invention, it is possible to provide a novel silylated polyether and a sealant containing the same as an active ingredient. Further, this silylated polyether is curable at room temperature, and is cured by moisture in the atmosphere to give a cured product having excellent mechanical properties, weather resistance, heat resistance and the like.
Therefore, the sealing material using this is industrially highly useful.

[Brief description of drawings]

FIG. 1 is a chart showing the results of IR spectrum analysis of the silylated polyether produced in Example 1.

FIG. 2 is a chart showing the result of ¹ H-NMR spectrum analysis of the silylated polyether produced in Example 1.

Claims (2)

[Claims] 1. (1) Both ends have the following formula (Formula 1): (Here, R ¹ , R ² and R ³ each independently represent a hydrolyzable group or an alkyl group, provided that R ¹ , R ^{2 and}
And at least two of R ³ are hydrolyzable groups), (2) the main chain is a copolymer of tetrahydrofuran and ethylene oxide, and the number of moles of the tetrahydrofuran residue is tetrahydrofuran residue. 15 to the total number of moles of groups and ethylene oxide residues
85%, and (3) between the main chains and / or between the main chain and the terminal group is (Chemical formula 2): (Wherein R _a represents a linear or branched aliphatic group or aromatic group), and
(4) A silylated polyether having a number average molecular weight of 500 to 50,000. 2. A room temperature curable sealant containing the silylated polyether according to claim 1 as an active ingredient.