JP7262238B2 - epoxy resin composition - Google Patents

Description

The present invention relates to epoxy resin compositions.

BACKGROUND ART Conventionally, epoxy resin compositions have been widely used as adhesives for structural members of automobiles, for example. For example, Patent Literature 1 and Patent Literature 2 describe adhesives for automobile structural members containing a resin composition containing a photopolymerizable component and a rubber component or an epoxy resin, or a rubber-modified epoxy resin. ing.

JP 2009-57447 A Japanese Patent Publication No. 2010-523800

Automobile structural adhesives contain various fillers, but there is a problem that the use of mineral/metal fillers with a high specific gravity makes the automobile body heavy and hinders the reduction of fuel consumption. The adhesive described in Patent Literature 2 uses foamed microballoons, but the adhesiveness to the substrate, the strength, and the breaking state are insufficient.

The present invention has been made in view of such conventional problems, and by using a non-inflatable balloon, the specific gravity of the adhesive is reduced, and the epoxy adhesive is excellent in adhesion to the substrate, strength, and breaking state. An object of the present invention is to provide a resin composition, particularly an epoxy resin composition that is preferably used for a heat-curing one-component epoxy resin adhesive.

In order to achieve the above object, the epoxy resin composition of the present invention is
at least one epoxy resin;
a block urethane resin, a non-expanding balloon, a silane coupling agent,
is characterized by including

It is possible to provide an epoxy resin composition that reduces the specific gravity of the adhesive and is excellent in adhesion to substrates, strength, and destructive state, and in particular, an epoxy resin composition that is preferably used as a heat-curing one-liquid type epoxy resin adhesive. can.

An embodiment according to the present invention will be described below. However, the constituent elements described in the following embodiments are examples, and are not intended to limit the technical scope of the present invention only to them.

The present invention is an epoxy resin composition (hereinafter referred to as a resin composition according to the present embodiment) containing at least one epoxy resin and block urethane resin as main components, a non-expandable balloon, and a silane coupling agent. .

Each component will be described in detail below.

≪Epoxy Resin≫
The epoxy resin, which is one of the main components in the resin composition according to the present embodiment, includes, for example, bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, Bifunctional glycidyl ether epoxy resins such as epoxy compounds having a bisphenyl group such as a biphenyl type, polyalkylene glycol type, alkylene glycol type epoxy compounds, epoxy compounds having a naphthalene ring, and epoxy compounds having a fluorene group; Polyfunctional glycidyl ether type epoxy resins such as phenol novolak type, ortho cresol novolak type, trishydroxyphenylmethane type, and tetraphenylolethane type; synthetic fatty acid glycidyl ester type epoxy resins such as dimer acid; ,N',N'-tetraglycidyldiaminodiphenylmethane (TGDDM), tetraglycidyl-m-xylylenediamine, triglycidyl-p-aminophenol, N,N-diglycidylaniline. Resin; epoxy compounds having a tricyclodecane ring, and the like.

The epoxy resin in the resin composition according to the present embodiment preferably contains a bisphenol A type epoxy resin and a carboxyl group-containing nitrile-butadiene rubber-modified epoxy resin. These epoxy resins are described in detail below.

<Bisphenol A type epoxy resin>
The bisphenol A type epoxy resin, which is one of the main components in the resin composition according to this embodiment, will be described.

The epoxy resin contained in the resin composition according to this embodiment is a bisphenol A type epoxy resin having a bisphenol skeleton. By containing a bisphenol A type epoxy resin, a resin composition having sufficient strength as an adhesive can be obtained.

The bisphenol A type epoxy resin according to this embodiment preferably has an epoxy equivalent of 150 or more and 260 or less. Moreover, the amount of the bisphenol A type epoxy resin in the resin composition according to the present embodiment is preferably 20 to 80% by mass. By setting it as the said range, the resin composition which is more excellent in impact resistance is obtained.

<Carboxyl Group-Containing Nitrile-Butadiene Rubber-Modified Epoxy Resin>
The carboxyl group-containing nitrile-butadiene rubber-modified epoxy resin, which is one of the main components in the resin composition according to the present embodiment, will be described.

The resin composition according to the present embodiment contains an epoxy resin having a rubber skeleton, and specifically contains a carboxyl group-containing NBR (nitrile-butadiene rubber)-modified epoxy resin. By containing the NBR-modified epoxy resin, a resin composition having excellent heat resistance, impact resistance, and flexibility can be obtained.

The NBR-modified epoxy resin according to the present embodiment preferably has an epoxy equivalent of 200 or more and 500 or less. Moreover, the amount of the NBR-modified epoxy resin in the resin composition according to the present embodiment is preferably 5 to 70% by mass. By setting it as the said range, the resin composition which is more excellent in impact resistance and flexibility is obtained.

The epoxy resin used in producing the NBR-modified epoxy resin is not particularly limited, and conventionally known epoxy resins can be used. Moreover, an epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more types.

In the present invention, the epoxy equivalent and addition amount of the NBR-modified epoxy resin are the epoxy equivalent and addition amount of the NBR-modified epoxy resin containing excess epoxy resin used during production.

≪Block urethane resin≫
In the resin composition according to the present embodiment, a urethane prepolymer obtained by reacting a polyhydroxy compound and a polyisocyanate compound is blocked with an active methylene compound, an oxime compound, a phenol compound, a lactam compound, a secondary amine compound, or the like. contains block urethane resin.

<Polyhydroxy compound>
The polyhydroxy compound is not particularly limited in terms of its molecular weight, skeleton, etc., as long as it is a compound having two or more hydroxyl groups. Mixed polyols of these and the like are included.

Specific examples of polyhydric alcohols include ethylene glycol (EG), diethylene glycol, propylene glycol (PG), dipropylene glycol, (1,3- or 1,4-) butanediol, pentanediol, neo low-molecular-weight polyols such as pentyl glycol, hexanediol, cyclohexanedimethanol, glycerin, trimethylolpropane (TMP), 1,2,5-hexanetriol and pentaerythritol; sugars such as sorbitol;

As polyether polyols and polyester polyols, those derived from the above polyhydric alcohols may be used, or those derived from aromatic diols and amines shown below may be used.

Specific examples of aromatic diols include resorcinol (m-dihydroxybenzene), xylylene glycol, 1,4-benzenedimethanol, styrene glycol, and 4,4'-dihydroxyethylphenol; bisphenol A structure (4,4'-dihydroxyphenylpropane), bisphenol F structure (4,4'-dihydroxyphenylmethane), brominated bisphenol A structure, hydrogenated bisphenol A structure, bisphenol S structure, bisphenol AF structure those having a skeleton; and the like.

Further, specific examples of amines include ethylenediamine and hexamethylenediamine, and specific examples of alkanolamines include ethanolamine and propanolamine.

Examples of polyether polyols include at least one compound selected from the compounds exemplified as the above polyhydric alcohols, the above aromatic diols, and the above amines, ethylene oxide, propylene oxide, butylene oxide (tetramethylene oxide), tetrahydrofuran. and polyols obtained by adding at least one selected from alkylene oxides, styrene oxides, and the like.

Specific examples of such polyether polyols include polyethylene glycol, polypropylene glycol (PPG), polypropylene triol, ethylene oxide/propylene oxide copolymer, polytetramethylene glycol (PTMG), polytetraethylene glycol, sorbitol polyol, and the like. is mentioned.

Similarly, examples of polyester polyols include condensates of polyhydric alcohols, aromatic diols, amines, and polybasic carboxylic acids; lactone polyols; polycarbonate polyols; . Specific examples of the lactone-based polyol include those obtained by ring-opening polymerization of lactones such as ε-caprolactone, α-methyl-ε-caprolactone, ε-methyl-ε-caprolactone, and the like with an appropriate polymerization initiator. Examples include those having hydroxyl groups at both ends.

Specific examples of other polyols include acrylic polyols; polybutadiene polyols; and polymer polyols having a carbon-carbon bond in the main chain skeleton such as hydrogenated polybutadiene polyols.

These polyhydroxy compounds may be used singly or in combination of two or more.

<Polyisocyanate compound>
The polyisocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups, and examples thereof include aliphatic polyisocyanates, aromatic polyisocyanates, and alicyclic polyisocyanates.

Specific examples of polyisocyanate compounds include aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, and norbornane diisocyanate (NBDI); TDI (e.g., 2,4- tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI)), MDI (e.g. 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4 ′-diphenylmethane diisocyanate (2,4′-MDI)), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1 Aromatic polyisocyanates such as ,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate; transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (H6XDI), dicyclohexylmethane diisocyanate alicyclic polyisocyanates such as (H12MDI); One type of these polyisocyanate compounds may be used alone, or two or more types may be used in combination.

<Blocking agent>
Blocking agents for block urethane include active methylene compounds such as malonic acid diesters and acetoacetic esters, oxime compounds such as methyl isobutyl ketone oxime and methyl ethyl ketone oxime, phenol compounds (mono- and di-forms) such as nonylphenol and bisphenol A, ε- Examples include lactam compounds such as caprolactam and secondary amine compounds such as dicyclohexylamine. A urethane prepolymer containing free isocyanate groups at the terminals is obtained by the reaction of the polyhydroxy compound and the polyisocyanate. A block urethane resin can be obtained by reacting this urethane prepolymer with these blocking agents.

The amount of the blocking agent to be added is preferably 5 to 30 mass % with respect to the total of the polyhydroxy compound and the polyisocyanate compound.

<Catalyst>
Catalysts suitable for the reaction to synthesize block urethane resins are commercially available, e.g. metal or transition metal compounds based on aluminum, tin, zinc, titanium, manganese, bismuth or zirconium, e.g. dibutyl tin dilaurate, zinc octoate. , titanium tetrabutylate or zirconium octoate.

Moreover, the amount of the block urethane resin in the resin composition according to the present embodiment is preferably 3 to 50% by mass. By setting the content within the above range, a resin composition having excellent strength and durability even at high temperatures can be obtained.

≪Other ingredients≫
The resin composition according to the present embodiment contains, as components other than the main components described above, other components such as the following non-expandable balloons, silane coupling agents, curing agents, and curing accelerators. Each component is described in detail below.

<Non-inflatable balloon>
Glass balloons and resin balloons are preferably used as the non-inflatable balloon according to the present embodiment. Resin balloons are constructed of relatively inelastic materials such as PET, nylon, polyurethane, polyolefins, PVC, and other crosslinked polymers.
By using a non-expandable balloon, the weight of the epoxy resin composition of the present invention can be reduced.

<Silane coupling agent>
As the silane coupling agent according to the present embodiment, those having an epoxy group are effective. Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, epoxy group and alkoxysilane group in siloxane oligomer skeleton is preferably used.
These may be used individually by 1 type, and may be used in combination of 2 or more types.

<Curing agent>
As the curing agent according to the present embodiment, one that is commonly used as a curing agent for epoxy resins can be used as it is.

Specific examples of curing agents include dicyandiamide, 4,4′-diaminodiphenyl sulfone, imidazole derivatives such as 2-n-heptadecyl imidazole, isophthalic acid dihydrazide, N,N-dialkyl urea derivatives, N,N-di Alkylthiourea derivatives, acid anhydrides such as tetrahydrophthalic anhydride, isophoronediamine, m-phenylenediamine, N-aminoethylpiperazine, melamine, guanamine, boron trifluoride complex compounds, trisdimethylaminomethylphenol and the like. These may be used individually by 1 type, and may be used in combination of 2 or more types.

Among the above curing agents, dicyandiamide can be preferably used. Dicyandiamide is a latent curing agent that can be stably stored at room temperature and has the function of rapidly curing by being melted and activated by heating. Therefore, by using dicyandiamide, a resin composition having excellent strength and durability even at high temperatures can be obtained.

The content of the curing agent in the resin composition according to this embodiment is not particularly limited, and an optimum amount for each curing agent can be preferably used.

<Curing accelerator>
The curing accelerator according to this embodiment has the effect of accelerating the curing reaction of dicyandiamide, which is suitably used as a curing agent. The curing accelerator used in the composition of the present embodiment is not particularly limited as long as it has the effect of accelerating the curing reaction of dicyandiamide, and conventionally known curing accelerators can be used. Specific examples of curing accelerators include aliphatic dimethylurea and aromatic dimethylurea. One type of these curing accelerators may be used alone, or two or more types may be used in combination.

<Furthermore, other ingredients>
The resin composition according to the present embodiment may further contain inorganic fillers, organic or polymeric fillers, flame retardants, antistatic agents, conductivity-imparting agents, lubricants, slidability-imparting agents, surfactants, etc., depending on the application. It may contain agents, colorants, and the like. These may contain one type alone, or may contain two or more types in combination. Specific examples of other components include calcium carbonate, talc, wallastonite, fumed silica, aluminum hydroxide, calcium oxide, bentonite, kaolin, and carbon black.

<<Method for producing epoxy resin composition>>
The method for producing the resin composition according to the present embodiment is not particularly limited, and it can be produced by a conventionally known method. For example, it can be obtained by homogeneously kneading a bisphenol A type epoxy resin, an NBR-modified epoxy resin, a block urethane resin, a non-expandable balloon, a silane coupling agent, and, if necessary, other components at room temperature.

≪Example≫
The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

(Production of epoxy resin composition of Example 1)
Predetermined amount of bisphenol A type epoxy resin (epoxy equivalent = 190), NBR-modified epoxy resin (HyPox RA 1340 manufactured by CVC), Coronate 2532 (block urethane resin manufactured by Tosoh Corporation), glass balloon (S38 manufactured by 3M), dicyandiamide , 1-phenyl-3,3-dimethylurea, and 3-glycidoxypropyltrimethoxysilane were uniformly kneaded to obtain an epoxy resin composition. Table 1 shows the amount (parts by weight) of each component added.

(Production of epoxy resin composition of Example 2)
Predetermined amount of bisphenol A type epoxy resin (epoxy equivalent = 190), NBR-modified epoxy resin (HyPox RA 1340 manufactured by CVC), Coronate 2532 (block urethane resin manufactured by Tosoh Corporation), resin balloon (EMC40 manufactured by Sankyo Seifun Co., Ltd.) , dicyandiamide, 1-phenyl-3,3-dimethylurea, and 3-glycidoxypropyltrimethoxysilane were uniformly kneaded to obtain an epoxy resin composition. Table 1 shows the amount (parts by weight) of each component added.

(Production of epoxy resin composition of Comparative Example 1)
Predetermined amount of bisphenol A type epoxy resin (epoxy equivalent = 190), NBR-modified epoxy resin (HyPox RA 1340 manufactured by CVC), Coronate 2532 (block urethane resin manufactured by Tosoh Corporation), glass balloon (S38 manufactured by 3M), dicyandiamide , and 1-phenyl-3,3-dimethylurea were uniformly kneaded to obtain an epoxy resin composition. Table 1 shows the amount (parts by weight) of each component added.

(Production of epoxy resin composition of Comparative Example 2)
Predetermined amount of bisphenol A epoxy resin (epoxy equivalent = 190), NBR-modified epoxy resin (HyPox RA 1340 CVC), Coronate 2532 (block urethane resin, manufactured by Tosoh Corporation), foamed microballoons (Matsumoto Microsphere MFL- 81GTA, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), dicyandiamide, 1-phenyl-3,3-dimethylurea, and 3-glycidoxypropyltrimethoxysilane were uniformly kneaded to obtain an epoxy resin composition. Table 1 shows the amount (parts by weight) of each component added.

(evaluation)
The composition obtained in each example and each comparative example was applied to the surface of a mild steel plate and cured at a predetermined temperature (180 ° C.) for a predetermined time (30 minutes), and a tensile shear strength test and T-peel test were performed. It was subjected to a strength test. The test was performed under the following conditions.

Tensile shear strength test: Compliant with JIS K-6850 Test speed 50mm/min
Coating film thickness 0.2mm
Coating area 13 x 25mm
T-type peel strength test: Complies with JIS K-6854 Test speed 50mm/min
Coating film thickness 0.2mm
Coating area 25×75mm
Table 1 shows other conditions.

Table 1 shows the results for each evaluation.

In each example, the tensile shear strength and T-peel strength were good. On the other hand, in Comparative Examples 1 and 2, the strength was lower than that of the Examples. Therefore, it was found that the epoxy resin compositions in Examples had excellent strength.

Claims (5)

An epoxy resin composition comprising an epoxy resin consisting of a mixture of a bisphenol A type epoxy resin and a carboxyl group-containing nitrile-butadiene rubber-modified epoxy resin (NBR-modified epoxy resin), a block urethane resin, a glass balloon , and a silane coupling agent. and may contain an inorganic filler, wherein the inorganic filler is selected from calcium carbonate, talc, fumed silica, aluminum hydroxide, bentonite, kaolin, or carbon black. Epoxy resin composition. The epoxy resin composition according to claim 1 , wherein the silane coupling agent is a silane coupling agent having an epoxy group. 3. The epoxy resin composition according to claim 1 , wherein said epoxy resin composition further comprises dicyandiamide. 4. The epoxy resin composition according to claim 3 , further comprising a urea-based catalyst as a curing accelerator for said dicyandiamide. 5. The epoxy resin composition according to any one of claims 1 to 4 , which is applied to an automobile structural member and used for the purpose of bonding the member.