JP2020111700A - Curable resin composition - Google Patents

Abstract

To provide a curable resin composition that is excellent in sagging resistance after short-term storage and long-term storage stability.SOLUTION: A curable resin composition contains a urethane prepolymer, carbon black, and a malonate compound represented by the formula (1). In the formula (1), R1OOCCH2COOR2 formula, R1 and R2 independently represent a hydrocarbon group having 8 or more carbon atoms.SELECTED DRAWING: None

Description

The present invention relates to a curable resin composition.

BACKGROUND ART Conventionally, a one-component moisture-curable urethane resin composition is often used as a sealing agent, an adhesive, etc. for automobiles, constructions and structures.
For example, Patent Document 1 discloses a one-component moisture-curable urethane resin composition containing a malonate compound (claims, etc.). Patent Document 1 describes that the above composition has excellent storage stability.

JP, 2003-201397, A

Under these circumstances, the present inventors have examined a one-part moisture-curable urethane resin composition containing a malonate compound, and found that it is excellent in long-term storage stability (long-term storage stability), but short-term. It was found that the droop resistance after storage (droop resistance after short-term storage) may be insufficient.

Therefore, in view of the above circumstances, an object of the present invention is to provide a curable resin composition having excellent droop resistance after short-term storage and excellent long-term storage stability.

As a result of diligent studies on the above problems, the present inventors have found that the above problems can be solved by using a specific malonate compound as the malonate compound, and have reached the present invention.
That is, the present inventors have found that the above problems can be solved by the following configurations.

(1) A curable resin composition containing a urethane prepolymer, carbon black, and a malonate compound represented by the formula (1) described below.
(2) The curable resin composition according to (1), wherein in the formula (1), R ¹ and R ² are each independently an alkyl group having 8 to 18 carbon atoms.
(3) The curable resin composition according to (1) or (2), wherein the content of the malonate compound is 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the urethane prepolymer. ..

As shown below, according to the present invention, it is possible to provide a curable resin composition having excellent droop resistance after short-term storage and long-term storage stability.

The curable resin composition of the present invention will be described below.
In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.
Further, each component may be used alone or in combination of two or more. Here, when two or more kinds of each component are used in combination, the content of the component means the total content unless otherwise specified.

The curable resin composition of the present invention (hereinafter, the “curable resin composition of the present invention” is also referred to as the “composition of the present invention”) is represented by a urethane prepolymer, carbon black and the following formula (1). A curable resin composition containing a malonate compound.
R ¹ OOCCH ₂ COOR ² Formula (1)
In formula (1), R ¹ and R ² each independently represent a hydrocarbon group having 8 or more carbon atoms.

Since the composition of the present invention has such a constitution, it is considered that the above-mentioned effects can be obtained. Although the reason is not clear, it is presumed that the malonate compound represented by the above formula (1) (malonate compound having a hydrocarbon group with a large number of carbon atoms) improves the thixotropy of the composition.

[Urethane prepolymer]
As mentioned above, the composition of the present invention contains a urethane prepolymer having an isocyanate group.
With respect to the urethane prepolymer, an aspect having an isocyanate group at the terminal is mentioned as one of the preferable aspects because the effect of the present invention is more excellent.
One molecule of the urethane prepolymer preferably has a plurality of isocyanate groups, more preferably two isocyanate groups, for the reason that the effect of the present invention is more excellent.
The content of the isocyanate group is preferably 0.5 to 5 mass% with respect to the total amount of the urethane prepolymer, because the effect of the present invention is more excellent.

The polyisocyanate used in the production of the urethane prepolymer is not particularly limited as long as it has two or more isocyanate groups in the molecule.
Examples of the polyisocyanate used in the production of the urethane prepolymer include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI; for example, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate), , 4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate Aromatic polyisocyanates such as;
Hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (H ₆ XDI) Aliphatic polyisocyanates (including cycloaliphatic polyisocyanates), such as dicyclohexylmethane diisocyanate (H ₁₂ MDI);
These carbodiimide modified polyisocyanates;
These isocyanurate modified polyisocyanates may be mentioned.

The polyisocyanate is preferably an aromatic polyisocyanate and more preferably MDI because of its excellent curability.

The compound (active hydrogen compound) having two or more active hydrogen-containing groups in one molecule used in the production of the urethane prepolymer is not particularly limited. Examples of the active hydrogen-containing group include a hydroxyl group (OH) group, an amino group, and an imino group.
Preferable examples of the active hydrogen compound include a polyol compound having two or more hydroxyl (OH) groups in one molecule, and among them, a polyol compound is preferable.

The polyol compound used in the production of the urethane prepolymer is not particularly limited as long as it is a compound having two or more hydroxy groups. For example, polyether polyols; polyester polyols; polymer polyols having a carbon-carbon bond in the main chain skeleton such as acrylic polyols, polybutadiene diols, hydrogenated polybutadiene polyols; low molecular weight polyhydric alcohols; and mixed polyols thereof. .. Among them, polyether polyol is mentioned as one of the preferable embodiments.

The polyether polyol is not particularly limited as long as it has a polyether as a main chain and has two or more hydroxy groups. The polyether is a group having two or more ether bonds, and specific examples thereof include groups having ^a total of two or more structural units —R ^a —O—R ^b —. Here, in the above structural unit, R ^a and R ^b each independently represent a hydrocarbon group. The hydrocarbon group is not particularly limited. For example, a linear alkylene group having 1 to 10 carbon atoms can be mentioned.
Examples of the polyether polyol include polyoxyethylene diol (polyethylene glycol), polyoxypropylene diol (polypropylene glycol: PPG), polyoxypropylene triol, ethylene oxide/propylene oxide copolymer, polytetramethylene ether glycol (PTMEG). , Polytetraethylene glycol, sorbitol-based polyols and the like.

The polyether polyol is preferably polypropylene glycol or polyoxypropylene triol from the viewpoint of excellent compatibility with polyisocyanate.
The weight average molecular weight of the polyether polyol is preferably 500 to 20,000 from the viewpoint that the viscosity of the urethane prepolymer obtained by the reaction with isocyanate can have an appropriate fluidity at room temperature. In the present invention, the weight average molecular weight is a polystyrene conversion value obtained by the GPC method (solvent: tetrahydrofuran (THF)).

The urethane prepolymer is preferably a urethane prepolymer obtained by reacting a polyether polyol and an aromatic polyisocyanate from the viewpoints of excellent adhesiveness and curability, and polyoxypropylene diol and polyoxypropylene triol are preferred. The urethane prepolymer obtained by reacting at least one selected from the group consisting of and diphenylmethane diisocyanate is more preferable.
The urethane prepolymers may be used alone or in combination of two or more.

The method for producing the urethane prepolymer is not particularly limited. For example, polyisocyanate is used such that 1.5 to 2.5 moles of isocyanate groups react with 1 mole of active hydrogen-containing group (eg, hydroxy group) of the active hydrogen compound, and these are mixed and reacted. A urethane prepolymer can be manufactured by this. Hereinafter, the number of moles of isocyanate groups in the polyisocyanate with respect to 1 mole of the active hydrogen-containing group in the active hydrogen compound is also referred to as "NCO/OH".

[Carbon black]
As mentioned above, the composition of the present invention contains carbon black.
As the carbon black used in the composition of the present invention, conventionally known ones can be used as in the case of a normal one-pack type polyurethane composition.
Examples of the carbon blacks include SAF (Super Abrasion Furnace), ISAF (Intermediate Super Abrasion Furnace), HAF (High Abrasion Furnace FrenceFrench), HAF (High Abrasion FurnaceFurnaceFurnanceFurnaceFurnaceFurnaceFurnace), HAF (High Abrasion FurnaceFrenchFrench), FEF (Fast ExtractionFurnanceFurnaceFurnanceFurnaceFurnanceFurnaceFurnaceFurnaceFurnace), HAF (High Abrasion FurnaceFrenchFrenchFrench), FAF (Fast ExtrusionFurnanceFurnaceFurnaceFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrenchFrench) , FT (Fine Thermal), MT (Medium Thermal), and the like.
Specifically, the above-mentioned SAF is Seast 9 (manufactured by Tokai Carbon Co., Ltd.), ISAF is Showa Black N220 (manufactured by Showa Cabot Co., Ltd.), HAF is Seast 3 (manufactured by Tokai Carbon Co., Ltd.), Niteron #200 (Shin Nikka) Examples of FEF include HTC#100 (manufactured by Chubu Carbon Co.) and the like. Also, Asahi #55 (manufactured by Asahi Carbon Co., Ltd.) as a GPF, Seast 5 (manufactured by Tokai Carbon Co., Ltd.), Asahi #50 (manufactured by Asahi Carbon Co., Ltd.), Mitsubishi #5 (manufactured by Mitsubishi Chemical Co., Ltd.) as an SRF, and FT as Asahi Thermal (manufactured by Asahi Carbon Co., Ltd.), HTC#20 (manufactured by Chubu Carbon Co., Ltd.) and Asahi #15 (manufactured by Asahi Carbon Co., Ltd.) and the like can be mentioned. Among them, HAF is preferable because the effect of the present invention is more excellent.

In the composition of the present invention, the content of carbon black is preferably 20 to 100 parts by mass, and 30 to 80 parts by mass with respect to 100 parts by mass of the urethane prepolymer described above, because the effect of the present invention is more excellent. More preferably, 40 to 70 parts by mass is more preferable.

[Specific malonate compound]
As described above, the composition of the present invention contains the malonate compound represented by the following formula (1) (hereinafter, also referred to as “specific malonate compound”).
R ¹ OOCCH ₂ COOR ² Formula (1)
In formula (1), R ¹ and R ² each independently represent a hydrocarbon group having 8 or more carbon atoms.

Examples of the above-mentioned hydrocarbon group include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group combining these.
The aliphatic hydrocarbon group may be linear, branched or cyclic. Specific examples of the aliphatic hydrocarbon group include a linear or branched alkyl group, a linear or branched alkenyl group, a linear or branched alkynyl group, and the like.
R ^A1 is preferably a hydrocarbon group, more preferably an aliphatic hydrocarbon group, and further preferably a linear alkyl group, for the reason that the effects of the present invention are more excellent. A linear alkyl group having 1 to 5 carbon atoms is particularly preferable.

The number of carbon atoms in the hydrocarbon group is preferably 20 or less, more preferably 15 or less, and further preferably 10 or less for the reason that the effect of the present invention is more excellent.

The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably a linear or branched alkyl group, and a branched alkyl group for the reason that the effect of the present invention is more excellent. Is more preferable.

Specific examples of the specific malonate compound include di-2-ethylhexyl malonate and dioctadecyl malonate.

In the composition of the present invention, the content of the specific malonate compound is 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the above-mentioned urethane prepolymer, because the effect of the present invention is more excellent. preferable.
In the composition of the present invention, the content of the specific malonate compound is preferably 0.1 part by mass or more based on 100 parts by mass of the above-mentioned urethane prepolymer, for the reason that the effect of the present invention is more excellent. 0.2 parts by mass or more is more preferable, 0.3 parts by mass or more is further preferable, and 0.4 parts by mass or more is particularly preferable.
In the composition of the present invention, the content of the specific malonate compound is preferably 4.0 parts by mass or less based on 100 parts by mass of the above-mentioned urethane prepolymer, because the effect of the present invention is more excellent. The amount is more preferably 0.0 part by mass or less, further preferably 2.0 parts by mass or less, and particularly preferably 1.0 part by mass or less.

In the composition of the present invention, the content of the specific malonate compound is preferably 0.01 to 10 mass% with respect to the content of carbon black described above, for the reason that the effect of the present invention is more excellent, and 0 0.1 to 9 mass% is more preferable, 0.2 to 8 mass% is still more preferable, and 0.5 to 5 mass% is particularly preferable.

[Arbitrary ingredients]
The composition of the present invention may contain components other than the components described above.

[Plasticizer]
The composition of the present invention may contain a plasticizer.
Examples of the plasticizer include diisononyl phthalate (DINP); diisononyl adipate (DINA), dioctyl adipate, isodecyl succinate; diethylene glycol dibenzoate, pentaerythritol ester; butyl oleate, methyl acetylricinoleate; tricresyl phosphate, Trioctyl phosphate; propylene glycol adipate polyester, butylene glycol adipate polyester and the like.
When the composition of the present invention contains a plasticizer, the content of the plasticizer is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the urethane prepolymer, because the effect of the present invention is more excellent. It is more preferably 5 to 30 parts by mass.

〔filler〕
The composition of the present invention may contain a filler.
The filler does not include carbon black.
Examples of the filler include calcium carbonate such as ground calcium carbonate, precipitated calcium carbonate (light calcium carbonate), colloidal calcium carbonate; fumed silica, pyrogenic silica, precipitated silica, ground silica, fused silica, and the like. Silica; diatomaceous earth; iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide; magnesium carbonate, zinc carbonate; wax clay, kaolin clay, calcined clay; these fatty acid-treated products, resin acid-treated products, urethane compound treatments And fatty acid ester-treated products; and the like.
When the composition of the present invention contains a filler, the content of the filler is preferably 20 to 70 parts by mass with respect to 100 parts by mass of the urethane prepolymer, because the effect of the present invention is more excellent. It is more preferably 30 to 50 parts by mass.

[Metal catalyst]
The composition of the present invention may contain a metal catalyst.
The metal catalyst is not particularly limited as long as it is a compound capable of promoting the reaction of isocyanate groups. For example, an organic metal catalyst and a metal catalyst composed of only a metal having no organic group (also referred to as an inorganic metal catalyst) can be mentioned.
Examples of the metal contained in the metal catalyst include tin, bismuth, and titanium.

The organic group contained in the organometallic catalyst is not particularly limited. Examples of the organic metal catalyst include metal carboxylates, alkoxides, and complexes. The organometallic catalyst can have, for example, at least one selected from the group consisting of a carboxylate ion, an alkyl group, a carboxylic acid, an alkoxy group, and a ligand. The carboxylate ion, alkyl group, carboxylic acid, alkoxy group and ligand are not particularly limited.

The metal catalyst preferably contains an organotin catalyst.

Examples of the organic tin catalyst include tin carboxylates such as dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin maleate, stannous octoate, dibutyltin diacetylacetonate and dioctyltin maleate; 1,3-diacetoxy-1. , 1,3,3-tetrabutyl-distannoxane and ethyl silicate are reacted so that the molar ratio is 1:0.8 to 1:1.2.

When the composition of the present invention contains a metal catalyst, the content of the metal catalyst is 0.001 to 1.0 part by mass based on 100 parts by mass of the urethane prepolymer because the effect of the present invention is more excellent. It is preferable that the amount is 0.008 to 0.08 parts by mass.

[Amine-based catalyst]
The composition of the present invention may contain an amine-based catalyst.
The amine catalyst is a compound that has a nitrogen atom and accelerates the reaction of the isocyanate group.

The amine-based catalyst is a tertiary amino group (one nitrogen atom is single-bonded with three carbon atoms, or one nitrogen atom is single-bonded with one carbon atom and double-bonded with another carbon atom). It is preferable to have
Examples of the amine catalyst having a tertiary amino group (tertiary amine) include trimethylamine, triethylamine, tripropylamine, tributylamine, triamylamine, trihexylamine, trioctylamine, trilaurylamine, dimethylethylamine. , Dimethylpropylamine, dimethylbutylamine, dimethylamylamine, dimethylhexylamine, dimethylcyclohexylamine, dimethyloctylamine, dimethyllaurylamine, triallylamine, tetramethylethylenediamine, triethylenediamine, N-methylmorpholine, 4,4'-( Oxydi-2,1-ethanediyl)bis-morpholine, N,N-dimethylbenzylamine, pyridine, picoline, dimethylaminomethylphenol, trisdimethylaminomethylphenol, 1,8-diazabicyclo[5.4.0]undecene- 1,1,4-diazabicyclo[2.2.2]octane, triethanolamine, N,N'-dimethylpiperazine, tetramethylbutanediamine, bis(2,2-morpholinoethyl)ether, bis(dimethylaminoethyl) ) Ether and the like can be mentioned.

The amine-based catalyst preferably contains a dimorpholino diethyl ether structure because it is excellent in the effects of the present invention, and is excellent in moisture curing property, storage stability, and drooping resistance.
The dimorpholino diethyl ether structure is a structure having dimorpholino diethyl ether as a basic skeleton.
In the dimorpholino diethyl ether structure, the hydrogen atom of the morpholine ring may be substituted with a substituent. The substituent is not particularly limited. For example, an alkyl group is mentioned. Examples of the alkyl group include a methyl group and an ethyl group.

Examples of the amine-based catalyst having a dimorpholino diethyl ether structure include compounds represented by the following formula (9).

In the above formula (9), R ¹ and R ² are each independently an alkyl group, and m and n are each independently 0, 1 or 2.
Specific examples of the amine-based catalyst having a dimorpholino diethyl ether structure include dimorpholino diethyl ether, di(methylmorpholino)diethyl ether, and di(dimethylmorpholino)diethyl ether.
The amine catalysts may be used alone or in combination of two or more.

When the composition of the present invention contains an amine-based catalyst, the content of the amine-based catalyst is more excellent in the effect of the present invention, and is more excellent in curability and storage stability of the uncured product. The amount is preferably 0.05 to 1.0 part by mass, and more preferably 0.07 to 0.5 part by mass, relative to 100 parts by mass of the polymer.

[Other additives]
The composition of the present invention may further contain other additives.
Examples of the additives include surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, and thixotropic agents. The kind and content of the additive can be appropriately selected.

[Method for preparing curable resin composition]
The method for preparing the composition of the present invention is not particularly limited. For example, a method of mixing the above-mentioned components may be used.

[Uses, etc.]
Since the composition of the present invention can be cured by moisture, it is particularly useful as a one-component moisture-curable curable resin composition (one-component moisture-curable urethane resin composition).
The composition of the present invention can be cured under the conditions of -20 to +50°C, for example, by moisture in the atmosphere.

Applications of the composition of the present invention include, for example, adhesives.
The adherend (base material) to which the composition of the present invention can be applied is not particularly limited. Examples thereof include metals (including coated plates and electrodeposition coated steel plates), plastics, rubbers, and glasses.
A primer may be used for the adherend, if necessary. The primer is not particularly limited. Examples thereof include a composition containing a compound having an isocyanate group and/or a hydrolyzable silyl group such as an alkoxysilyl group.
The composition of the present invention can be used, for example, as an adhesive between a vehicle body and a window glass; an adhesive between a window glass and parts such as rocket pins and hinges.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[Preparation of curable resin composition]
Each curable resin composition was prepared by mixing the components shown in Table 1 below with a stirrer in the proportions (parts by mass) shown in the same table.
The amount of urethane prepolymer in Table 1 is the net amount of urethane prepolymer.

[Evaluation]
The following evaluation was performed about the obtained curable resin composition.

<Drunk resistance>
The obtained curable resin composition was extruded on a glass plate with a right triangle bead having a base of 6 mm and a height of 10 mm in a strip shape, and then the hypotenuse of the composition extruded in the shape of the right triangle was downward. The glass plate is vertically (90° angle) so that the sides of the composition having a height of 10 mm are horizontal, the glass plate is fixed, and the glass plate is held vertically at 20° C. and 65% relative to each other. It was left for 30 minutes under the condition of humidity.
The distance h (mm) in which the apex of the right triangle of the composition drooped down 30 minutes after the glass plate was made vertical was measured, and the droop resistance was evaluated according to the following criteria (initial). The results are shown in Table 1.
Also, the curability of the curable resin composition after storage at 50° C. for 6 days was evaluated in the same manner. The results are shown in Table 1 (after 6 days at 50°C). From the viewpoint of droop resistance after short-term storage, the droop resistance of the curable resin composition after storage at 50° C. for 6 days is preferably ◯ or Δ, and more preferably ◯.
・○: Distance h is less than 2 mm ・△: Distance h is 2 mm or more and less than 3 mm ・x: Distance h is 3 mm or more

<Storage stability>
The obtained curable resin composition was put in a cartridge and a plunger was inserted. After leaving this in an environment of 40° C. for 3 weeks, the cartridge was opened and the state of the curable resin composition was examined. Then, the long-term storage stability was evaluated according to the following criteria. The results are shown in Table 1. It is preferably ⊚ or ◯, and more preferably ⊚.
-A: No change in viscosity was observed.
-○: The viscosity was slightly increased.
-X: Hardened.

Details of each component in Table 1 are as follows.
-Urethane prepolymer: urethane prepolymer synthesized as follows Polyoxypropylene diol (weight average molecular weight 2000) 500 g, polyoxypropylene triol (weight average molecular weight 5000) 750 g, and 4,4'-diisocyanate phenyl methane (4,4 ′-Diphenylmethane diisocyanate) (molecular weight 250) (214 g) was mixed (NCO/OH=1.8 at this time), 160 g of diisononyl phthalate was further added, and the mixture was stirred at 80° C. for 24 hours in a nitrogen stream to react. , A urethane prepolymer containing 1.95% of isocyanate groups was synthesized.
-Carbon black: Niteron #200 manufactured by Shin Nikka Carbon Co., Ltd.
-Plasticizer: diisononyl phthalate-Calcium carbonate: Super SS (heavy calcium carbonate) manufactured by Maruo Calcium Co., Ltd.
-Comparative malonate compound: diethyl malonate-Specific malonate compound 1: Malonate compound represented by the above-mentioned formula (1) (R ¹ : 2-ethylhexyl group, R ² : 2-ethylhexyl group)
Specific malonate compound 2: Malonate compound represented by the above formula (1) (R ¹ : 2-ethylhexyl group, R ² : octadecyl group)
Specific malonate compound 3: Malonate compound represented by the above formula (1) (R ¹ : octadecyl group, R ² : octadecyl group)
Metal catalyst: Neostan U-810 (dioctyltin dilaurate) manufactured by Nitto Kasei Co., Ltd.
Amine-based catalyst: dimorpholino diethyl ether (DMDEE) manufactured by San-Apro

As can be seen from Table 1, all of Examples 1 to 9 containing the specific malonate compound exhibited excellent droop resistance after short-term storage and long-term storage stability. Among them, Examples 1-2, 4-5, and 7-8 in which the content of the specific malonate compound was 3.0 parts by mass or less with respect to 100 parts by mass of the urethane prepolymer were more excellent after droop resistance after short-term storage. Showed sex. Among them, Examples 2, 5 and 8 in which the content of the specific malonate compound was 0.10 parts by mass or more relative to 100 parts by mass of the urethane prepolymer showed more excellent long-term storage stability.

On the other hand, Comparative Examples 1 to 3 which did not contain the specific malonate compound had insufficient droop resistance after short-term storage or long-term storage stability.

Claims (3)

A curable resin composition containing a urethane prepolymer, carbon black, and a malonate compound represented by the following formula (1).
R ¹ OOCCH ₂ COOR ² Formula (1)
In formula (1), R ¹ and R ² each independently represent a hydrocarbon group having 8 or more carbon atoms. The curable resin composition according to claim 1, wherein in the formula (1), R ¹ and R ² are each independently an alkyl group having 8 to 18 carbon atoms. The curable resin composition according to claim 1 or 2, wherein the content of the malonate compound is 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the urethane prepolymer.