JPH0477516A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition giving a curable material having excellent adhesiveness, flexibility, impact resistance and toughness containing terminal silyl groups, imino groups, a hydroxyl group-containing polyether copolymer, an epoxy compound, a catalyst accelerating hydrolysis of silyl groups and an epoxy curing agent. CONSTITUTION:(A) A copolymer expressed by formula I [Q<1> and Q<2> are bifunctional hydrocarbon; (m) is 10-500; (n) is a number of >=1 making molecular weight of the polymer to 1000-50000; Z is expressed by formula II (Q<3> is bifunctional hydrocarbon; R<1> is monofunctional hydrocarbon; X is hydrolyzing group; (a) is 1-3) or formula III (Q<4> is same species as Q<3>); A is heterocyclic compound having two imino groups bonding to different two carbon atoms in the molecule, aromatic ring or a compound in which two mercapto groups are bonded with carbon atoms constituting a hetero ring or expressed by formula IV (R<2> is H or monofunctional hydrocarbon; Q<5> is same species as Q<3>); R<3>NH2 CR<3> is same species as R<1>] is mixed with (B) a compound containing at least two epoxy groups in a molecule in average, (C) a catalyst accelerating hydrolysis of hydrolyzable silyl groups and (D) an epoxy curing agent to afford the objective curable composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a curable composition that provides a cured product with improved adhesion, flexibility, impact resistance and toughness.

[Technical background of the invention and its problems]

Epoxy resins are used in a wide range of applications such as adhesives, laminates, various molding materials, and plywood, but their cured products are hard, lack flexibility, and are brittle.

In order to solve this drawback, it has been proposed to mix an epoxy resin with a polyether having a hydrolyzable silyl group at the end of the molecular chain (Japanese Patent Laid-Open No. 61-14
No. 8225, No. 61-244723, No. 61-268
Publication No. 720). However, with this method, the epoxy resin and polyether separate as the curing progresses, and the two do not unite and harden, so the expected strength cannot be obtained, especially when wiping the deep part of the cured product. There was a problem that it was not done.

[Purpose of the invention]

The purpose of the present invention is to provide a curable composition that does not have the above-mentioned problems, and as a result of intensive studies to achieve this purpose, the present inventor has discovered a composition having a hydrolyzable silyl group at the end of the molecular chain. By mixing and curing an epoxy resin with a polymer that has a hydroxyl group that can react with an epoxy group in its molecular chain, it exhibits uniform curing properties regardless of whether it is on the surface or deep, and has excellent adhesiveness and flexibility. It was discovered that a cured product with excellent impact resistance and toughness can be obtained, and the present invention was completed.

[Structure of the invention]

That is, the present invention is based on the general formula (A) [wherein (11,02 is a divalent hydrocarbon group; m is 10 to
500, n is the molecular weight of the polymer from 1000 to 5000
A number greater than or equal to 0; a group represented by 03, 4 is a divalent hydrocarbon group, R' is a monovalent hydrocarbon group, X is a hydrolyzable group, a is an integer from 1 to 3; A is a residue of a compound selected from the following ■～■2
Valent group ■Heterocyclic compound having two imino groups bonded to two different carbon atoms in the molecule ■Aromatic compound with two mercapto groups bonded to the carbon atoms constituting the aromatic ring or heterocycle; or A diamine compound represented by a heterocyclic compound -CH,C)l-Zl, where Q5 is a divalent hydrocarbon group. A copolymer represented by (B) a compound having an average of two or more epoxy groups in the molecule (C) a catalyst that promotes the hydrolysis of hydrolyzable silyl groups;
and (D) an epoxy curing agent.

The copolymer (A) is a characteristic base polymer that provides a cured product with good curability and excellent toughness in the present invention. Such base polymers are, for example, the following (
It is obtained by reacting the three components a), υ), and (C), and the polymer that meets your needs can be obtained by combining them, but it contains a hydroxyl group that can react with the epoxy group of (B) in the molecular chain. One of its characteristics is that it has

Such base polymers are disclosed in Japanese Patent Application Laid-Open Nos. 62-181320, 62-230822, 62-256828, 63-83131, 63 by the present inventors.
-125524 and JP-A-2-55726. These constituent components will be explained below.

In the polyether (a), the oxyalkylene unit represented by 010 is preferably an oxyethylene unit, an oxypropylene unit, or a combination system of an oxyethylene unit and an oxypropylene unit, which is easy to obtain raw materials and polymerize, and is liquid even at a high degree of polymerization. Oxypropylene units are particularly preferred because they are easy to retain. The degree of polymerization m of the oxyalkylene unit is selected from the range of 10 to 500. When m is less than 10, it becomes difficult to obtain a polymer that has a viscosity that provides practical workability and that provides a cured product with excellent flexibility and toughness. On the other hand, if m is larger than 500, the cured product tends to be non-uniform, the hardened state of the cured product deteriorates, and the toughness decreases.

The divalent hydrocarbon group at port 2 includes a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group. Among these groups, a methylene group is preferred from the viewpoint of easy availability of raw materials.

Typical examples of these (a) include those obtained by condensing epichlorohydrin with polyoxyethylene or polyoxypropylene, both ends of which are blocked with hydroxyl groups, in the presence of a basic catalyst.

The compound (b) is a crosslinking agent that reacts with the epoxy groups of (a) and (C). Of these, the compound ■ is published in JP-A-63
-125524, and must be a heterocyclic compound having two imino groups bonded to two different carbon atoms in the molecule. Examples of these (2) include the following because they are easy to synthesize and obtain. That is, 3 Among these, piperazine, 2,5-dimethylpiperazine, 1,4-diiminocyclopentane, perhydrophenazine, perhydropyrimidine, perhydro-1,
3,5-oxadiazine and perhydro-1,3,5-thiadiazine are preferred, and piperazine is particularly recommended from the viewpoint of easy availability of raw materials. It goes without saying that in addition to these compounds having two imino groups, compounds having one or three or more imino groups can also be used in amounts within a range that does not impair the purpose of the present invention.

The compound (2) is disclosed in JP-A No. 63-83131, and is a compound that has two mercapto groups in the molecule that react with the epoxy groups of (a) and (C). It is necessary that the compound is a cyclic compound, and that the mercapto group is bonded to a carbon atom constituting the aromatic ring or heterocycle. These (1) components include 2,5-dimercapto-1,3,4-thiadiazole and dimercaptobenzene because of the ease of obtaining raw materials, ease of synthesis due to reactivity with epoxy groups, and yield. , dimercaptotoluene, dimercaptoxylene, dimercaptonaphthalene, etc. are recommended. Among these, 2,5-dimercapto-1,3
, 4-thiadiazole is particularly preferred for the above reasons.

The amine compounds of ■ and ■ are disclosed in JP-A No. 63-33425.
R' It is shown in the R2 publication, and H~-Q5-NH (
In the formula, R2 is a hydrogen atom or a monovalent hydrocarbon group, and 05 is a divalent hydrocarbon group). ), CH3(CH2) 3N
+(2,C)I3([:R2),NR2,CH2=CH
Examples include CH, NR2, H[](CH2)2NH2°.

Examples of silicon compounds 03 and 04 include those similar to 02, but Q3 is preferably a methylene group from the viewpoint of easy availability of raw materials. In addition, Q4 is an ethylene group, trimethylene group, or
and tetramethylene groups are preferred, and trimethylene groups are particularly preferred.

The monovalent hydrocarbon group for R1 can be selected from alkyl groups, aryl groups, aralkyl groups, etc., but a methyl group is recommended from the viewpoint of ease of synthesis and raw material availability.

As the hydrolyzable group for X, an alkoxy group having 1 to 6 carbon atoms is preferable, a methoxy group or an ethoxy group is preferable since it is necessary to have high hydrolyzability, and a methoxy group is particularly preferable. The number a of hydrolyzable groups is selected within the range of 1 to 3, but it is preferable that a is 2 in order to obtain a composition that provides a flexible and tough cured product.

Specific examples of component (C) include T-glycidoxypropyltrimethoxysilane, T-glycidoxybutyltrimethoxysilane, T-glycidoxypropyltriethoxysilane, and γ-glycidoxybutyltrimethoxysilane. Ethoxysilane, Methyl (γ-glycidoxypropyl) dimethoxysilane, Methyl (T-glycidoxybutyl) dimethoxysilane, Methyl (T-glycidoxypropyl) jetoxysilane, Methyl (T-glycidoxybutyl) Jetoxysilane, phenyl (T-glycidoxybropyl) dimethoxysilane, phenyl (T-glycidoxybutyl) dimethoxysilane, dimethyl (T-glycidoxybropyl)
Methoxysilane, dimethyl (T-glycidoxybutyl)
Methoxysilane and compounds in which these alkoxy groups are replaced with alkoxyalkoxy groups, acyloxy groups, N,N-dialkylamino groups, N-alkylamido groups, N,N-dialkylaminoxy groups, ketoxime groups, alkenoxy groups, etc. can give.

The polymer (A) is the polymer (a) and (C
) and (b).

The reactions (a), (b) and (C) are preferably carried out at a temperature higher than the ambient temperature, for example 50 to 150°C. At that time, methanol, ethanol, phenol,
Salicylic acid, tris(dimethylaminomethyl)phenol, benzylmethylamine, tributylamine and 2
- Preference is given to using compounds such as methylimidazole as reaction accelerator. Methanol is one of the preferred ones. Although it is not necessary to use a solvent when carrying out this reaction, a hydrocarbon-based, ether-based, or ester-based solvent may be used.

The theoretical molar ratio of (a), (b) and (C) is (a):(a):(C)=p:(p+1):
2 (in the formula, p represents a natural number starting from 1).

However, in reality, it is acceptable to use (b) and (C) in amounts slightly exceeding the theoretical amounts.

The reaction procedure includes (a), (b) and (C
) may be added and reacted at the same time, but first, (a) and (b) are reacted in an amount exceeding the equivalent thereof to elongate the chain, and then (C) is added in an amount equivalent to or slightly above the required amount. It is preferable to add and react because it is easier to control the degree of polymerization and it is possible to reliably introduce a hydrolyzable group to the end of the molecular chain.

In addition, n is a number greater than or equal to 1, and may be 1, but (A
) must be selected so that the molecular weight of the polymer falls within the range of 1.000 to 50.000. If the molecular weight is less than 1,000, a cured product with excellent flexibility and toughness cannot be obtained, whereas if it exceeds 50,000, workability decreases, which is not preferable.

Examples of the compound having an epoxy group (B) include bisphenol A epoxy resin, bisphenol F epoxy resin, tetrabromobisphenol A epoxy resin,
Novolak type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidyl ether type epoxy resin of bisphenol A propylene oxide adduct, p-oxybenzoic acid glycidyl ether type epoxy “W” resin, aminophenol type epoxy resin, diaminodiphenylmethane type Examples include epoxy resin, urethane-modified epoxy resin, glycidyl ether type epoxy resin of polyhydric alcohol, and hydantoin type epoxy resin.The number of epoxy groups is determined from the viewpoint of quickly curing and forming a three-dimensional network structure. It is necessary for an average of two or more to exist in the molecule.

It is necessary to exist.

From flexibility, adhesiveness and toughness, component (A)/component (B) = 5
The range of /95 to 9515 is preferable.

The catalyst (C) that promotes hydrolysis of the hydrolyzable silyl group quickly hydrolyzes the hydrolyzable silyl group present at the molecular chain end of the polymer (A) to form a three-dimensional network structure. It is a component for forming. These (C) components include tin carboxylates such as tin octylate; organic tin carboxylates such as dibutyltin dilaurate, dibutyltin dilarate, and dibutyltin phthalate; reaction products with organic tin oxides and their esters; tetrabutyl titanate. Examples include organic titanate esters such as; amines; amine salts; quaternary ammonium salts; and guanidine compounds. The amount of catalyst (C) is arbitrarily selected depending on how long it takes to cure and is not particularly limited. Using an amount that exceeds
This is not preferable because oozing or precipitation occurs after curing.

As the epoxy curing agent of component (D), various conventionally known ones can be used, such as ethylenediamine, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, N-aminoethylpiperazine, bis(4- Amines such as amino-3-methylcyclohexyl)methane, m-lxylyleneamine isophoronediamine, 2.4.6-)lis(dimethylaminomethyl)phenol; tertiary amine salts; polyamide resins; imidazoles; dicyanamides ; boron trifluoride complex compounds, carboxylic anhydrides such as phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and pyromellitic anhydride; alcohols; phenols; carboxylic acids; and other thiol group-containing curing agents. An example is the combined use of a tertiary amine.

The amount of the curing agent (D) is selected so that the number of epoxy groups in the component (B) is equal to the number of functional groups in the curing agent, but is not necessarily limited thereto.

Additionally, the compositions of the present invention may contain UV absorbers, antioxidants, viscosity modifiers, modifiers such as coupling agents, fillers such as fumed silica, ground quartz, calcium carbonate, titanium oxide, iron oxide. , pigments such as carbon black can also be blended.

The composition of the present invention can be cured by either room temperature curing or heat curing method, and the temperature suitable for curing is 5 to 5.
The temperature is 150°C.

〔Effect of the invention〕

The composition of the present invention has excellent adhesion, flexibility, and toughness, and is therefore ideal as an adhesive for various parts and a bonding agent for various plywood boards.The composition of the present invention also has excellent deep hardening properties, so
It is also suitable as a raw material for various binders and composite materials.

〔Example〕

The present invention will be explained below with reference to examples, but the present invention is not limited thereto. In the examples, all parts represent parts by weight.

Synthesis Example 1 5 moles of glycidyl group-end-blocked polyoxypropylene [10 (epoxy)] having an average degree of polymerization of 15 and a molecular weight of approximately 1000.25°C and a viscosity of 270 cSt. : Methanol in an amount corresponding to 1 mole and 10% of polyoxypropylene was added, and heating stirring was started at 60° C. under a nitrogen atmosphere. 8H3 hours after the start of heating and stirring
2.2 mol of methyl(T-glycidoxypropyl)dimethoxysilane represented by (0['H.)* was added, and heating and stirring was continued under the same conditions. After adding the above silane
After heating and stirring for an hour, methanol was distilled off and the mixture was heated to 25°C.
The viscosity is 15,000 cSt, the number average molecular weight is 60
A polymer (hereinafter referred to as P-1) whose molecular chain ends were blocked with a hydrolyzable silyl group represented by the following formula was obtained as a pale yellow viscous liquid.

H Kano H Mouth H II3 I ["H2) Ryo-5i (口CH3) 2 Synthesis Example 2 5 moles of glycidyl group-terminated polyoxypropylene with an average degree of polymerization of 32 and a molecular weight of about 2000.25°C and a viscosity of 550 cSt [ 10 (epoxy) equivalents] 6 moles of clopentane and ethanol in an amount equivalent to 10% of polyoxypropylene were added, and heating and stirring was started at 80° C. under a nitrogen atmosphere.

Eight hours after the start of heating and stirring, CH3 was added and heating and stirring was continued under the same conditions. After adding the above silane and heating and stirring for 8 hours, ethanol was distilled off to form a pale yellow viscous liquid with a viscosity at 25°C of 26,000 cSt and a number average molecular weight of 11,000. A polymer (hereinafter referred to as P2) whose molecular chain terminals were blocked with hydrolyzable silyl groups was obtained.

3 moles [6 (epoxy) equivalents] of glycidyl group-end-blocked polyoxypropylene having an average degree of polymerization of 50 and an intermolecular viscosity of about 3000.25°C of 970 cSt.
Methanol in an amount corresponding to 10% of the mole and polyoxypropylene was added, and heating stirring was started at 60° C. under a nitrogen atmosphere. Eight hours after the start of heating and stirring, H
2CH3) 2H Synthesis Example 3 Heating and stirring were continued under the same conditions. After adding the above silane and heating and stirring for 8 hours, methanol was distilled off and the viscosity at 25°C was 22,000 cSt.

A pale yellow viscous liquid having a number average molecular weight of 10.000 was obtained, which was a polymer represented by the following formula whose molecular chain terminals were blocked with hydrolyzable silyl groups (hereinafter referred to as P-3).

Synthesis Example 4 5 moles of glycidyl group-end-blocked polyoxypropylene [10(epoxy)-dimercap)-1,3,4-thiadiazole having an average degree of polymerization of 15 and a molecular weight of about 1.000.25°C and a viscosity of 270 cSt. Methanol in an amount corresponding to 6 moles and 10% of polyoxypropylene was added, and heating and stirring was started at 60° C. under a nitrogen atmosphere. A portion was taken out at 4 hour intervals from the start of heating and stirring, and a peak due to protons of epoxide methylene (2.67 ppm based on tetramethylsilane) was observed by NMR.
And the viscosity was measured at 25°C. 12 hours after the start of heating and stirring, the peak due to protons of epoxide methylene disappeared, and before the start of heating and stirring, the peak was 100%.
Since the viscosity of the mixture which was cSt reached 1,800 cSt, CH3CI'12CHC1'+2-0iCL)-TSl(O
CH3) 2 methyl\0/l(T-glycidoxypropyl)dimethoxysilane
．． 2 mol was added, and heating and stirring was continued under the same conditions. After adding the above silane, a portion of the reaction mixture was withdrawn at 4-hour intervals, iodine was added to react with the mercapto group, and the remaining iodine was back-titrated with sodium thiosulfate to detect the mercapto group. However, since it was no longer detected 12 hours after the addition of silane, heating and stirring was terminated, and methanol was distilled off. The obtained reaction product had a viscosity of 19.0OOcSt at 25°C,
The specific gravity at the same temperature is 1. It is a pale yellow viscous liquid with a number average molecular weight of 6.500 as measured by GPC, and is a polymer (P-4) whose molecular terminals are blocked with a hydrolyzable silyl group represented by the following formula. It was confirmed that.

CI'la ICHa)T-S i (DC)la) 2 Synthesis Example 5 5 moles of glycidyl group-end-blocked polyoxypropylene with an average degree of polymerization of 32 and a molecular weight of about 2,000.25°C and a viscosity of 550 cSt [ 1O (epoxy) equivalent], 6 moles of 2,5-dimercapto-1,3,4-thiadiazole and an amount of ethanol equivalent to 10% of polyoxypropylene were added, and the mixture was heated and stirred at 60°C under a nitrogen atmosphere. started. A portion was taken out at 4:00 MrIJ intervals from the start of heating and stirring, and the peak due to protons of epoxide methylene was observed by NMR, and the viscosity at 25° C. was measured. 12 hours after the start of heating and stirring,
The peak due to the proton of epoxide methylene disappears,
The viscosity was 270 cSt before heating and stirring started, but the viscosity was 4.4.
Because it reached 00C3t, C)1. C) 1-C) 12-[1i CH2 catty Si (D
['H-CH-)\0/T-glycidoxypropyltriethoxysilane represented by 3 is 2.2
mol was added, and heating and stirring was continued under the same conditions. After adding the above silane, a portion was taken out at 4 hour intervals and mercapto groups were detected using the same method as in Example 1. As mercapto groups were no longer detected 12 hours after addition of the silane, heating and stirring was stopped. , 25 by distilling off the ethanol
The viscosity at ℃ is 29.0OOcSt, and the specific gravity at the same temperature is 1.01. A pale yellow viscous liquid having a number average molecular weight of 11,000 as measured by GPC (polymer P-5 whose molecule end was blocked with a hydrolyzable silyl group represented by the following formula) was obtained.

DHDH -CH2C11C1 (2-0i CHx) TSi (mouth C)
12cH3)sH Synthesis Example 6 For 3 moles of glycidyl group-end-blocked polyoxypropylene [6 (epoxy) equivalent] having an average degree of polymerization of 50 and a molecular setting of 3.000.25°C and a viscosity of 970 cSt, 4 moles of zene and Add methanol in an amount equivalent to 10% of polyoxypropylene and heat at 60°C under nitrogen atmosphere.
Heating and stirring was started. A portion was taken out at 4-hour intervals from the start of heating and stirring, and the peak due to protons of epoxide methylene was observed by NMR, and the viscosity at 25° C. was measured. 12 hours after the start of heating and stirring,
The peak due to the proton of epoxide methylene disappears,
The viscosity was 400 cSt before heating and stirring started, but the viscosity was 5.2 cSt.
Since the temperature reached 00 cSt, 2.2 mol of methyl(γ-glycidoxyprobyl)dimethoxysilane was added and heating and stirring was continued under the same conditions. A portion of the silane was taken out at 4-hour intervals after the addition of the silane, and mercapto groups were detected using the same method as in Example 1.
After 2 hours, it was no longer detected, so heating and stirring was stopped, methanol was distilled off, and the viscosity at 25°C was 25.
．． 000cSt, and the specific gravity at the same temperature is 1.01.
A pale yellow viscous liquid with a number average molecular weight of 500 as measured by GPC (polymer P-6 whose molecule end was blocked with a hydrolyzable silyl group represented by the following formula) was obtained.

leaf leaf leaf leaf (CL?r　St　(OCH3)　a Reference example 1 Molecular weight g, ooo, at the end of the molecular chain CH.

(C1l, D) 2Si-C)1. CH, CH2-0-
The polyoxypropylene having the following will be hereinafter referred to as (P-7).

Examples 1 to 6, Comparative Examples 1 to 2 P-1 to 6 obtained in Synthesis Examples 1 to 6 and P-7 of Reference Example 1
Add and mix the epoxy compound, hydrolysis catalyst and epoxy curing agent shown in Table 1 to 100 parts of each,
Samples 1-7 were prepared. In addition, Sample 8 was prepared as a mixture of only an epoxy resin and an epoxy curing agent. These samples were poured onto a Teflon plate to a thickness of about 2 mm and heated to 20°C.
After curing for 7 days, it was removed from the Teflon plate and the curing properties of the surface layer and back layer were observed. Next, the cured product sheet was punched out into JIS No. 2 dumbbells and physical properties were measured. These results are also shown in Table 1. Comparative Example 1 is a comparative example in which polyoxypropylene having a hydrolyzable silicon group at the end of the molecular chain is used instead of the polymer of the present invention, and Comparative Example 2 is
is a comparative example that does not use the polymer of the present invention.

Claims (1)

[Claims] 1 (A) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, Q^1 and Q^2 are divalent hydrocarbon groups; m is 10
~500 number, n is the molecular weight of the polymer from 1000 to 500
A number of 1 or more that is 00;
There are chemical formulas, tables, etc. ▼ The group shown by Q^3, Q^4 is a divalent hydrocarbon group, R
^1 is a monovalent hydrocarbon group, X is a hydrolyzable group, a is 1-
An integer of 3; A is a divalent group that is a residue of a compound selected from the following (1) to (4). Cyclic compounds, (2) Aromatic compounds or heterocyclic compounds in which two mercapto groups are bonded to the carbon atoms constituting the aromatic ring or heterocycle (3) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (in the formula , R^
2 is a hydrogen atom or a monovalent hydrocarbon group, Q^5 is a divalent hydrocarbon group) A diamine compound (4) R^3NH_2 (wherein R^3 is a monovalent hydrocarbon group) A copolymer represented by the following amine compound] (B) a compound having an average of two or more epoxy groups in the molecule (C) a catalyst that promotes the hydrolysis of hydrolyzable silyl groups;
and (D) an epoxy curing agent. 2 The copolymer of (A) is (a)▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, Q^1 and Q^2 are divalent hydrocarbon groups, m is 10
Indicates a number of ~500. ) A polyether whose molecular chain ends are blocked with epoxy groups. (b) Compounds selected from the following (1) to (4) (1) Two imino groups bonded to two different carbon atoms in the molecule.
(2) Aromatic compounds or heterocyclic compounds in which two mercapto groups are bonded to the carbon atoms constituting the aromatic ring or heterocycle (3) ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ (In the formula, R^
2 is a hydrogen atom or a monovalent hydrocarbon group, Q^5 is a divalent hydrocarbon group) A diamine compound (4) R^3NH_2 (wherein R^3 is a monovalent hydrocarbon group) The curable composition according to claim 1, which is obtained by the reaction of an amine compound represented by the formula (c) and an organosilicon compound represented by the general formula ▲ where there are mathematical formulas, chemical formulas, tables, etc. ▼ (Z is as described above). .