JPH072828B2 - Curable resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel curable resin composition containing an oxypropylene polymer containing a reactive silicon group and an epoxy resin.

[Background Art] Conventionally, epoxy resins have been used in various molding materials, adhesives, paints,
It is used in a wide range of applications, including plywood and laminated products, but a common problem with these applications is that the cured product is brittle and, when used as an adhesive, has low peel strength.

On the other hand, oxypropylene polymers having reactive silicon groups (silicon-containing groups containing silicon atoms bonded to hydroxyl groups or hydrolyzable groups, which can form siloxane bonds) have the interesting property of curing even at room temperature to form rubbery elastic bodies, but they usually have the drawback of having low strength in the cured product, which limits their applications.

Therefore, in order to significantly improve the drawbacks of brittleness of cured epoxy resins and insufficient strength of cured oxypropylene polymers having reactive silicon groups, a curable resin composition combining an epoxy resin and an oxypropylene polymer having reactive silicon groups has been proposed (for example, JP-A-61-2425).
No. 7723, Japanese Patent Publication No. 61-268720).

However, since it has been difficult to produce high molecular weight oxypropylene polymers with narrow molecular weight distributions (high monodispersity), only polymers with wide molecular weight distributions (high polydispersity) have been known among oxypropylene polymers containing reactive silicon groups.

Compositions using oxypropylene polymers having such a wide molecular weight distribution have high viscosity before curing, are difficult to handle, and have various practical inconveniences.

Recently, it has been reported that polyoxypropylene having a narrow molecular weight distribution can be obtained. The present inventors have discovered that a composition containing an epoxy resin and a polymer having a narrow molecular weight distribution oxypropylene polymer as the main chain and reactive silicon groups introduced at the terminals thereof has low viscosity and is easy to handle before curing, and after curing, the cured product has excellent tensile properties as well as chemical resistance and water resistance, which led to the present invention.

[Disclosure of the Invention] The curable resin composition of the present invention comprises: (A) a polymerized main chain; and having at least one silicon atom-containing group (reactive silicon group) containing a silicon atom to which a hydroxyl group or a hydrolyzable group is bonded, wherein the oxypropylene polymer has an Mw/Mn (weight average molecular weight/number average molecular weight) ratio of 1.6 or less and a number average molecular weight (Mn) of 6,000 or more, and (B) an epoxy resin.

[Best Mode for Carrying Out the Invention] The reactive silicon group contained in the oxypropylene polymer of component (A) used in the present invention is not particularly limited, but a representative example is a group represented by the following general formula (1):

[Wherein ^R1 and ^R2 each represent an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a triorganosiloxy group represented by (R') _3SiO- ; when two or more ^R1s or ^R2s are present, they may be the same or different. Here, R' represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the three R's may be the same or different. X represents a hydroxyl group or a hydrolyzable group; when two or more Xs are present, they may be the same or different. a represents 0, 1, 2, or 3; b represents 0;
1 or 2 respectively. In the formula (I), b may be different. m represents an integer of 0 to 19, provided that a + Σb ≧ 1 is satisfied.] The hydrolyzable group represented by X above is not particularly limited, and may be any conventionally known hydrolyzable group. Specific examples include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, a hydrogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group are preferred, but an alkoxy group such as a methoxy group is particularly preferred from the viewpoint of mild hydrolysis and ease of handling.

This hydrolyzable group or hydroxyl group has 1 to 3 units per silicon atom.
It is preferable that (a+Σb) is 1 to 5. When two or more hydrolyzable groups or hydroxyl groups are present in the reactive silicon group, they may be the same or different.

The reactive silicon group may contain one silicon atom,
There may be two or more, but in the case of a reactive silicon group in which silicon atoms are linked by a siloxane bond or the like, there may be about 20.

The reactive silicon group represented by the following general formula (2) is preferred from the viewpoint of availability.

(wherein R ² , X, and a are the same as above.) Specific examples of R ¹ and R ² in the general formula (1) above include alkyl groups such as methyl and ethyl groups, cycloalkyl groups such as cyclohexyl groups, aryl groups such as phenyl groups, aralkyl groups such as benzyl groups, (R′) ₃ S where R′ is a methyl group or a phenyl group, etc.
Examples of suitable groups include triorganosiloxy groups represented by the formula iO-. Methyl groups are particularly preferred as ^R1 , ^R2 and R'.

The number of reactive silicon groups contained in one molecule of the oxypropylene polymer is preferably at least one, and more preferably 1.1 to 5.
If the number is less than 1, the curing property will be insufficient and it will be difficult to exhibit good rubber elastic behavior.

The reactive silicon group may be present at the end or inside of the oxypropylene polymer molecular chain. When the reactive silicon group is present at the end of the molecular chain, the effective network chain amount of the oxypropylene polymer component contained in the finally formed cured product increases, making it easier to obtain a rubber-like cured product that exhibits high strength, high elongation, and a low elastic modulus.

The oxypropylene polymer constituting the polymer main chain in component (A) used in the present invention is The oxypropylene polymer may be linear or branched, or may be a mixture of these. It may also contain other monomer units, etc.
It is preferred that the monomer units represented by the above formula are present in the polymer in an amount of 50% by weight or more, preferably 80% by weight or more.

The number average molecular weight (Mn) of this oxypropylene polymer is preferably 6,000 or more, but more preferably 6,000 to 30,000.
The ratio of weight average molecular weight to number average molecular weight (Mw/Mn) is 1.6 or less, and the molecular weight distribution is extremely narrow (high monodispersity). The value of Mw/Mn is preferably 1.5 or less, and more preferably 1.4 or less. The molecular weight distribution can be measured by various methods, but is usually measured by gel permeation chromatography (GPC). Because the molecular weight distribution is narrow despite the high number average molecular weight,
The composition of the present invention has a low viscosity before curing and is easy to handle, and after curing it exhibits good rubber-like elastic behavior and exhibits excellent adhesive strength when used as an adhesive.

The oxypropylene polymer having a reactive silicon group, which is component (A) of the present invention, is preferably obtained by introducing a reactive silicon group into an oxypropylene polymer having a functional group.

It is extremely difficult to obtain an oxypropylene polymer having a high molecular weight, a narrow molecular weight distribution, and functional groups by the usual polymerization method of oxypropylene (anionic polymerization using caustic alkali) or a chain extension reaction method using this polymer as a raw material. However, there are some special polymerization methods, such as those disclosed in JP-A-61-197631,
JP-A-61-215622, JP-A-61-215623, JP-A-61-
These polymers can be obtained by the methods described in Japanese Patent Publication Nos. 218632, 27250/1971, and 15336/1984, etc. Note that, since the introduction of reactive silicon groups tends to broaden the molecular weight distribution compared to the polymer before introduction, it is preferable that the molecular weight distribution of the polymer before introduction is as narrow as possible.

The reactive silicon group can be introduced by a known method, for example, the following method.

(1) An oxypropylene polymer having a functional group such as a hydroxyl group at its terminal is reacted with an organic compound having an active group and an unsaturated group that is reactive with the functional group, and then the resulting reaction product is reacted with a hydrosilane having a hydrolyzable group to perform hydrosilylation.

(2) An oxypropylene polymer having a terminal functional group such as a hydroxyl group, an epoxy group, or an isocyanate group (hereinafter referred to as a Y functional group) is reacted with a compound having a functional group (hereinafter referred to as a Y' functional group) that is reactive with the Y functional group and a reactive silicon group.

The silicon compound having the Y' functional group is, for example, γ-
Amino group-containing silanes such as (2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, etc.; mercapto group-containing silanes such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, etc.; epoxy silanes such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.; vinyltriethoxysilane, γ-methacryloyl Specific examples include, but are not limited to, vinyl-type unsaturated group-containing silanes such as γ-acryloyloxypropyltrimethoxysilane and γ-acryloyloxypropylmethyldimethoxysilane; chlorine atom-containing silanes such as γ-chloropropyltrimethoxysilane; isocyanate-containing silanes such as γ-isocyanatepropyltriethoxysilane and γ-isocyanatepropylmethyldimethoxysilane; and hydrosilanes such as methyldimethoxysilane, trimethoxysilane, and methyldiethoxysilane.

Of the above methods, method (1) or method (2) in which a polymer having a terminal hydroxyl group is reacted with a compound having an isocyanate group and a reactive silicon group is preferred.

Examples of the epoxy resin as component (B) used in the present invention include flame-retardant epoxy resins such as epichlorohydrin-bisphenol A type epoxy resins, epichlorohydrin-bisphenol F type epoxy resins, and glycidyl ether of tetrabromobisphenol A, novolac type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidyl ether type epoxy resins of bisphenol A propylene oxide adduct, p-oxybenzoic acid glycidyl ether ester type epoxy resins, m-aminophenol type epoxy resins, diaminodiphenylmethane type epoxy resins, urethane-modified epoxy resins, various alicyclic epoxy resins, N,N-diglycidyl aniline, N,N-diglycidyl-o-toluidine, triglycidyl isocyanurate,
Examples include polyalkylene glycol diglycidyl ether, glycidyl ether of polyhydric alcohol such as glycerin, hydantoin type epoxy resin, epoxidized products of unsaturated polymers such as petroleum resin, but are not limited to these, and commonly used epoxy resins can be used. In view of high reactivity during curing and the ease with which the cured product forms a three-dimensional network, epoxy resins containing at least two epoxy groups represented by the formula (I) are preferred. Bisphenol A type epoxy resins and novolac type epoxy resins are more preferred.

In the present invention, it is of course possible to use a curing agent for curing the epoxy resin in combination. The epoxy resin curing agent that can be used may be any commonly used curing agent for epoxy resin. Examples of such curing agents include amines such as triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, m-xylylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, and 2,4,6-tris(dimethylaminomethyl)phenol; tertiary amine salts; polyamide resins; imidazoles; dicyandiamides; ketimines; boron trifluoride complex compounds; carboxylic acid anhydrides such as phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecynylsuccinic anhydride, pyromellitic anhydride, and chlorenic anhydride; alcohols; phenols; and carboxylic acids.
It is not limited to these.

When the curing agent is used, the amount used varies depending on the type of epoxy resin and curing agent, but it is generally 100% of component (B).
The curing agent may be used in an amount ranging from 0.1 to 300 parts per part (parts by weight, the same applies hereinafter) depending on the purpose.

In the composition of the present invention, in order to improve the strength of the cured product, it is preferable to use, as component (C), a silicon compound containing in the molecule a functional group reactive with an epoxy group and a reactive silicon group.

Specific examples of the functional group in the silicon compound that can react with an epoxy group include primary, secondary, and tertiary amino groups;
Examples of the reactive silicon group include mercapto groups, epoxy groups, and carboxyl groups. Examples of the reactive silicon group include the same reactive silicon groups as those described above for component (A), with alkoxysilyl groups being particularly preferred from the standpoint of ease of handling.

Specific examples of such silicon compounds include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and
Aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-
Ureidopropyltriethoxysilane, N-β-(N-
Examples include amino group-containing silanes such as (vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and γ-anilinopropyltrimethoxysilane; mercapto group-containing silanes such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane and γ-mercaptopropylmethyldiethoxysilane; epoxy bond-containing silanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; and carboxysilanes such as β-carboxyethyltriethoxysilane, β-carboxyethylphenylbis(2-methoxyethoxy)silane and N-β-(N-carboxymethylaminoethyl)-γ-aminopropyltrimethoxysilane. These silicon compounds may be used alone or in combination of two or more.

The weight ratio of component (B) to component (A) in the composition of the present invention is (A)/(B) = 100/1 to 1/100. If the (A)/(B) ratio is less than 1/1000, it becomes difficult to obtain the effect of improving the impact strength and toughness of the epoxy resin cured product, and if the (A)/(B) ratio exceeds 100/1, the strength of the oxypropylene polymer cured product becomes insufficient. The preferred ratio of component (A) to component (B) cannot be determined in general because it varies depending on the application of the curable resin composition. For example, to improve the impact resistance, flexibility, toughness, peel strength, etc. of the epoxy resin cured product, it is preferable to use 1 to 100 parts of component (A) per 100 parts of component (B).
It is preferable to use 500 parts, more preferably 5 to 100 parts.
On the other hand, in order to improve the strength of the cured product of the oxypropylene polymer having a reactive silicon group, which is component (A),
It is advisable to use 1 to 200 parts, preferably 5 to 100 parts, of component (B) per 100 parts of component (A).

The silicon compound (component (C)) is used in an amount of ((A) + (B)) based on the weight ratio of the components (A) and (B).
It is preferable that the ratio of ((A)+(B))/(C) is in the range of 100/0.1 to 100/20, and more preferably ((A)+(B))/(C)=
Used in the range of 100/0.2 to 100/10.

There are no particular limitations on the method for preparing the curable resin composition of the present invention, and any of the usual methods can be used, such as blending the above-mentioned components and kneading them at room temperature or under heat using a mixer, roll, kneader, etc., or dissolving the components in a small amount of an appropriate solvent and mixing them. Furthermore, by appropriately combining these components, one-component or two-component formulations can also be prepared and used.

A silanol condensation catalyst (curing catalyst) may be used in the curable resin composition of the present invention. When using a silanol condensation catalyst, a wide variety of conventionally known catalysts can be used. Specific examples thereof include titanate esters such as tetrabutyl titanate and tetrapropyl titanate; tin carboxylates such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octoate, and tin naphthenate; reaction products of dibutyltin oxide and phthalate esters; dibutyltin diacetylacetonate; organoaluminum compounds such as aluminum trisacetylacetonate, aluminum trisethylacetoacetate, and diisopropoxyaluminum ethylacetoacetate; zirconium tetraacetate; chelate compounds such as acetylacetonate and titanium tetraacetylacetonate; lead octylate; butylamine, octylamine, dibutylamine, monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,4,6-tris(dimethylaminomethyl)phenol, morpholine, N-methylmorpholine,
Examples of silanol condensation catalysts include amine compounds such as 2-ethyl-4-methylimidazole and 1,8-diazabicyclo(5,4,0)undecene-7 (DBU), or salts of these amine compounds with carboxylic acids, low-molecular-weight polyamide resins obtained from excess polyamines and polybasic acids, reaction products of excess polyamines and epoxy compounds, silane coupling agents having amino groups such as γ-aminopropyltrimethoxysilane and N-(β-aminoethyl)aminopropylmethyldimethoxysilane, and other known silanol condensation catalysts such as other acidic catalysts and basic catalysts. These catalysts may be used alone or in combination of two or more.

The amount of these silanol condensation catalysts used is preferably about 0.1 to 20 parts per 100 parts of the oxypropylene polymer.
It is more preferable that the amount of the silanol condensation catalyst used is about 10 parts to 100 parts. If the amount of the silanol condensation catalyst used is too small relative to the oxypropylene polymer, the curing rate may be slow and the curing reaction may not proceed sufficiently. On the other hand, if the amount of the silanol condensation catalyst used is too large relative to the oxypropylene polymer, localized heat generation and foaming may occur during curing, making it difficult to obtain a good cured product, which is not preferable.

The curable resin composition of the present invention can be modified by incorporating various fillers, such as reinforcing fillers such as fume silica, precipitated silica, silicic anhydride, hydrated 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 and shirasu balloons, etc.; fibrous fillers such as asbestos, glass fibers and filaments can be used.

When it is desired to obtain a high strength hardened composition using these fillers, mainly fumed silica, precipitated silica, silicic anhydride,
A filler selected from hydrous silicic acid, carbon black, surface-treated fine calcium carbonate, calcined clay, clay, and activated zinc oxide is used in an amount of 1 to 100 parts per 100 parts of the reactive silicon group-containing oxypropylene polymer to obtain favorable results. In addition, when a curable composition having low strength and high elongation is desired, titanium oxide, calcium carbonate, magnesium carbonate, talc, ferric oxide,
Favorable results can be obtained by using a filler selected from zinc oxide and shirasu balloons in an amount of 5 to 200 parts per 100 parts of the reactive silicon group-containing oxypropylene polymer. Of course, these fillers may be used alone or in combination of two or more.

When using the reactive silicon group-containing oxypropylene polymer of the present invention, it is more effective to use a plasticizer in combination with a filler, since this increases the elongation of the cured product and allows for the incorporation of a large amount of filler.
These are commonly used, for example, phthalate esters such as dioctyl phthalate, dibutyl phthalate, butyl benzyl phthalate, etc.; aliphatic dibasic acid esters such as dioctyl adipate, isodecyl succinate, dibutyl sebacate, etc.; glycol esters such as diethylene glycol dibenzoate, pentaerythritol ester, etc.; butyl oleate,
The following plasticizers can be used alone or in the form of a mixture of two or more: aliphatic esters such as methyl acetylricinoleate; phosphate esters such as tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate; epoxy plasticizers such as epoxidized soybean oil and benzyl epoxy stearate; polyester plasticizers such as polyesters of dibasic acids and dihydric alcohols; polyethers such as polypropylene glycol and its derivatives; polystyrenes such as poly-α-methylstyrene and polystyrene; polybutadiene, butadiene-acrylonitrile copolymer, polychloroprene, polyisoprene, polybutene, chlorinated paraffins, etc. The amount of plasticizer is
Favorable results can be obtained when the amount is in the range of 0 to 100 parts per 100 parts of the reactive silicon group-containing oxypropylene polymer.

When using the curable resin composition of the present invention, various additives such as an adhesion improver, a physical property adjuster, a storage stability improver, an antiaging agent, an ultraviolet absorber, a metal deactivator, an ozone degradation inhibitor, a light stabilizer, an amine-based radical chain inhibitor, a phosphorus-based peroxide decomposer, a lubricant, a pigment, and a foaming agent may be further added as needed.

The curable composition of the present invention can be cured at temperatures as low as room temperature, and can also be rapidly cured at temperatures as high as about 100-150°C, so it can be used over a wide temperature range, from low to high, depending on the purpose. In particular, by selecting a combination of epoxy resin/epoxy resin curing agent that can be cured at room temperature, the curable composition of the present invention has the interesting feature of being able to produce a high-strength cured product by room temperature curing. Furthermore, if a liquid-type epoxy resin is used, a solventless curable composition can be easily prepared.

Although there are no particular limitations on the molding method for the curable resin composition of the present invention, when the epoxy resin is present in greater amounts than the reactive silicon group-containing oxypropylene polymer, molding by a method commonly used for molding epoxy resins, such as compression molding, transfer molding, or injection molding, is preferred, and molding by such a method can produce molded products with improved impact resistance, flexibility, toughness, etc., and laminated molded products such as copper-clad laminates and reinforced wood. Furthermore, in the case of such compositions, the composition can also be suitably used as an adhesive with improved peel strength, a foamed material with improved flexibility, a binder for fiberboard or particleboard, a paint, a binder for shell molds, a binder for plate linings, a binder for grinding wheels, a composite material formed by combining with glass fiber or carbon fiber, etc.

On the other hand, when the amount of reactive silicon group-containing oxypropylene polymer is greater than the epoxy resin, it is preferable to mold the polymer by a method commonly used for molding solid rubbers such as natural rubber or liquid rubber polymers such as polyurethane, and molding by such a method can produce molded rubber products, rubber foams, etc. with improved strength, etc. Furthermore, when the amount of reactive silicon group-containing oxypropylene polymer is greater than the epoxy resin, the polymer can also be suitably used as a rubber adhesive, sealing material, pressure-sensitive adhesive, etc.

In order to further clarify the present invention, the following examples are provided.

Synthesis Example 1: In a flask equipped with a stirrer, 2g of polyoxypropylene triol (Mw/Mn = 1.38, viscosity 89 poise) having a number average molecular weight of 15,000 was added.
20 g (0.0447 equivalents) of γ-isocyanatopropylmethyldimethoxysilane and 0.02 g of dibutyltin dilaurate were charged, and 8.45 g (0.0447 equivalents) of γ-isocyanatopropylmethyldimethoxysilane was added dropwise at room temperature under a nitrogen atmosphere. After the dropwise addition, the reaction was carried out at 75°C for 1.5 hours. IR spectroscopy revealed the disappearance of the NCO absorption near 2280 cm ^-1 and the increase in the 173
After confirming the formation of C═O absorption at around 0 cm ⁻¹ , the reaction was terminated to obtain 213 g of a colorless, transparent polymer.

Synthesis Example 2 1.5 A pressure-resistant glass reactor was charged with 401 g (0.081 equivalents) of polyoxypropylene triol having a molecular weight of 15,000 (Mw/Mn = 1.38, viscosity 89 poise) and placed under a nitrogen atmosphere.

At 137°C, 19.1 g (0.099 equivalents) of a 28% methanol solution of sodium methoxide was added dropwise from the dropping funnel, and the mixture was allowed to react for 5 hours, after which the volatile matter was removed under reduced pressure. The mixture was returned to a nitrogen atmosphere, and 9.0 g (0.118 equivalents) of allyl chloride was added dropwise, and the mixture was allowed to react for 1.5 hours.
5.6g of 28% sodium methoxide in methanol
Allylation was carried out using 2.7 g (0.035 equivalents) of allyl chloride.

This reaction product was dissolved in hexane and treated with aluminum silicate for adsorption. The hexane was then removed under reduced pressure to give 311 g of a yellow, transparent polymer (viscosity 68 poise).

270 g (0.065 equivalents) of this polymer was placed in a pressure-resistant glass reactor and placed under a nitrogen atmosphere. 25 g of a catalyst solution of chloroplatinic acid (H ₂ PtCl ₆ ·6H ₂ O) was dissolved in 500 g of isopropyl alcohol.
After stirring for 30 minutes, 6.24 g (0.059 equivalents) of dimethoxymethylsilane was added via the dropping funnel and the mixture was allowed to react at 90°C for 4 hours. After devolatilization, 260 g of a yellow, transparent polymer was obtained.

Comparative Synthesis Example 1: 90 parts of polypropylene glycol (number average molecular weight 2,500) and 10 parts of polypropylene triol (number average molecular weight 3,000)
Using the starting material, a molecular weight jump reaction was carried out using methylene chloride, followed by capping of the molecular chain ends with allyl chloride to obtain 800g of polypropylene oxide with a number average molecular weight of 8,000. 20g of methyldimethoxysilane was added to the resulting polypropylene oxide. 0.40ml of chloroplatinic acid catalyst solution (a solution of _8.9g of _H2PtCl6.6H2O dissolved in 18ml of isopropyl alcohol and 160ml of tetrahydrofuran) was then added, and the mixture was allowed to react at 80° _C for 6 hours.

The amount of silicon hydride groups remaining in the reaction solution was determined by IR spectroscopy and found to be almost non-existent. Quantitative analysis of silicon groups by NMR revealed that there were only a few silicon hydride groups at the molecular terminals. Polypropylene oxide having about 1.75 units per molecule was obtained.

The viscosity of the polymers obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1 was measured at 23°C using a Brookfield viscometer (BM type rotor No. 4, 12 rpm). The number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of each polymer were analyzed by GPC. GPC analysis was performed using a column packed with polystyrene gel (manufactured by Tosoh Corporation) and tetrahydrofuran as the distillation solvent at an oven temperature of 40°C. The results are shown in Table 1.
Shown in 1.

Examples 1 and 2 and Comparative Example 1 The polymers obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1
100 parts of Epicoat 828 (a bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.) 50 parts, Nocrak
SP (monophenol-based antioxidant manufactured by Ouchi Shinko Chemical Engineering Co., Ltd.) 1 part, 2,4,6-tris-(dimethylaminomethyl)phenol (DMP-30) 5 parts, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane 1 part,
#918 (organotin compound manufactured by Sankyo Kigosei Co., Ltd.) 1 part,
0.4 parts of water was thoroughly mixed in. Of the resulting compositions, the compositions of Examples 1 and 2 (using the polymers of Synthesis Examples 1 and 2) had lower viscosities and were easier to handle than the composition of Comparative Example 1 (using the polymer of Comparative Synthesis Example 1).

The resulting compositions were evaluated as adhesives in the following manner.

For measuring tensile shear strength, based on JIS K 6850,
H 4000 aluminum plate A-1050P (100 x 25 x 2 mm
Each of the compositions was applied with a spatula to the test pieces (test pieces of 100 mm x 100 mm), which were then stuck together and pressed together by hand to prepare test samples.

The T-peel adhesive strength was evaluated by a T-peel test based on JIS K 6854, but the aluminum plate A of JIS H 4000
Each of the above compositions was applied to a test piece of −1050P (200 × 25 × 0.1 mm) with a spatula to a thickness of about 0.5 mm, and the test piece was then stuck together.
Use a hand roller to prevent reciprocation in the length direction.
It was crimped once.

These adhesion test samples were then stored at 23°C for 2 days and then at 50°C.
The specimens were cured at 400°C for 3 days and then subjected to tensile tests. The tensile speed was set at 50 mm/min for the tensile shear test and 200 mm/min for the T-peel test. The results are shown in Table 2.

Examples 3, 4 and Comparative Example 2 The compositions prepared in Examples 1, 2 and Comparative Example 1 were applied to a sheet having a thickness of 2 m.
Spread it into a sheet of 100 mm, and store it at 23°C for 2 days, then at 50°C for 3 days.
A small piece of 1 cm x 1 cm was cut from this sheet-like cured product, its weight was measured, and then it was dissolved in 10% acetic acid aqueous solution for 10 days.
ml and stored at 50°C.

After 14 days, a small piece of the cured product was taken out and the surface was observed, and the results are shown in Table 3. In the table, ○ indicates no change, and × indicates that the surface was dissolved.

The surface of the small piece of Comparative Example 2 was sticky and dissolved, whereas there was almost no change in the small pieces of Examples 3 and 4. This shows that the acid resistance was greatly improved by the present invention.

[Industrial Applicability] The reactive silicon group-containing oxypropylene polymer used as component (A) in the curable resin composition of the present invention has a high number average molecular weight but a narrow molecular weight distribution. Therefore, the composition of the present invention, before curing,
The viscosity is lower and handling is easier than that of compositions containing conventional reactive silicon group-containing oxypropylene polymers having the same molecular weight and a broad molecular weight distribution.

Such a low viscosity before curing not only provides good workability, but also allows a large amount of filler to be blended, resulting in an excellent room temperature curable composition.

After curing, the crosslinked network becomes uniform, and the resin exhibits good rubber-like elastic behavior, such as improved elongation properties, and when used as an adhesive, it exhibits excellent adhesive strength.

Furthermore, the chemical resistance, such as acid resistance, has been unexpectedly improved, and the solvent resistance and water resistance are also excellent.

Thus, the curable resin composition of the present invention is of extremely high practical value.

──────────────────────────────────────────────────── Continued from the front page (56) References: Japanese Patent Application Publication No. 58-47054 (JP, A) Japanese Patent Application Publication No. 61-247723 (JP, A) Japanese Patent Application Publication No. 61-268720 (JP, A) Japanese Patent Application Publication No. 62-283120 (JP, A) Japanese Patent Application Publication No. 61-215623 (JP, A) European Patent Publication No. 397036 (EP, A)

Claims (4)

[Claims] Claim 1: (A) A polymer main chain and having at least one silicon atom-containing group containing a silicon atom to which a hydroxyl group or a hydrolyzable group is bonded, the silicon atom having a repeating unit represented by the formula: 2. The curable resin composition according to claim 1, wherein the polymer of component (A) has an Mw/Mn ratio of 1.5 or less. Claim 3: The number average molecular weight of the polymer of component (A) is 6.00
3. The curable resin composition according to claim 1, wherein the molecular weight is 0 to 30,000. 4. Any one of claims 1 to 3, wherein the silicon atom-containing group is present at the molecular chain terminal in the polymer of component (A).
Item 1. The curable resin composition according to item 1.