JPH02292381A - Adhesive composition - Google Patents

Abstract

PURPOSE: To obtain an adhesive composition excellent in oily surface adhesion, shelf stability and coating workability by incorporating a curing compound and a specified graphite fibril.

CONSTITUTION: A curing composition (e.g. a composition composed of a bisphenol A type epoxy compound, dicyandiamide and N,N-dimethylbenzylamine) and a graphite fibril having a diameter of 3.5-70 nm and a length of not less than 5 times the size of the diameter are incorporated to constitute an adhesive composition.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an adhesive composition, and particularly to an adhesive composition with excellent oil surface adhesion. [Prior Art] For example, in a hemming part of an automobile bonnet or trunk lid, an oil film of press oil or the like adheres to the surface of a steel plate, etc., and on the surface having such an oil film, that is, the oil surface, For example, in order to adhere members such as inner panels, parts, etc., it is necessary to use an adhesive that has excellent adhesion to oil surfaces (hereinafter referred to as oil surface adhesion).

Various proposals have been made to improve the adhesion of adhesives to oil surfaces, but conventional adhesives for oil surfaces have problems with storage stability, application workability, etc. The problem was that it wasn't sexual enough.

Recently, adhesives for oily surfaces have been developed with improved polymer components containing epoxy resins, or with oil-absorbing fillers added (e.g., JP-A-59-124972, JP-A-60-137980, JP-A-62-53387). , 61-1
55483 and 63-186786) have been proposed. However, these adhesives for oily surfaces have the disadvantage that they require various additives, such as viscosity-adjusting fillers, diluents, anti-sag agents, and anti-settling agents.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide an adhesive composition that has high oil surface adhesion and also has good storage stability and coating workability.

[Means for Solving the Problems] To achieve the above object, the present invention comprises a curable compound and a graphite fibril having a diameter of 3.5 to 70 nm and a length exceeding at least 5 times the diameter. The present invention provides an adhesive composition comprising:

Examples of the curable compound used in the adhesive composition of the present invention (hereinafter simply referred to as composition) include epoxy compounds, phenol compounds, polyurethane compounds, and the like. Among these curable resins, epoxy resins are preferred because they have good adhesion to metals.

The composition of the present invention is characterized by the type of curable compound used and the curing agent, curing accelerator and/or curing accelerator used in combination as necessary.
Alternatively, depending on the type of crosslinking agent, various curing types such as room temperature curing, thermosetting, photocuring, etc. can be prepared. Further, depending on the components and curing type of such a composition, it is suitably prepared as a one-part type or a two-part type.

Next, each curable compound will be explained.

First, when the curable compound is an epoxy compound, that is, a compound having an epoxy group, specific examples include shrimp chlorohydrin, bisphenol F, and bisphenol A.
5 ethylene glycol, butanediol, glycerin,
Condensation products with polyhydric alcohols or polyhydric phenols such as erythrit; condensation products between epichlorohydrin and novolak resins such as phenonovolac resins and Talezol novolak resins; cycloaliphatic epoxy compounds; glycidyl ester-based epoxy compounds; glycidyl Amine-based epoxy compounds; Heterocyclic epoxy compounds; Eboxy compounds derived from polyolefin polymers or copolymers; Eboxy compounds obtained by polymerization or copolymerization of glycidyl methacrylate; Epoxies obtained from glycerides of highly unsaturated fatty acids Compounds include polyalkylene ether type epoxy compounds, bromine-containing or fluorine-containing epoxy compounds, and the like. Among these compounds having an epoxy group, those with an epoxy equivalent of about 60
00 or less, more preferably 90 to 60
00 is selected.

Next, when using a polyurethane compound as a curable compound, a reaction product of an isocyanate compound and an active hydrogen compound can be mentioned as a specific example thereof. Here, examples of the isocyanate compound include polyisocyanate prebolimers having two or more isocyanate groups in the molecule, and examples of polyisocyanates for obtaining this brevolimer include various polyisocyanates such as aliphatic, aromatic, and alicyclic polyisocyanates. is used, but it may be used alone or in combination with a prebolimer compound. Furthermore, examples of active hydrogen compounds include polyol compounds and polyamine compounds.

Examples of polyol compounds include polyhydric alcohols such as ethylene glycol, 1,4-butanediol, pentaerythritol, glycerin, ethylene glycol, and propylene glycol; and polyethers obtained by addition polymerization of the polyhydric alcohols and alkylene oxides. Examples include polyols, polyester polyols obtained by condensation reaction of polyhydric alcohols and polybasic acids, polyester polyols obtained by other methods, acrylic polyols, castor oil polyols or derivatives thereof, epoxy polyols, and the like.

Examples of polyamine compounds include aliphatic polyamines,
Examples include various amines such as aromatic polyamines.

Further, when a phenol compound is used as the curable compound, specific examples include reaction products of the phenol compound and formaldehyde. Examples of the phenol compound include monohydric or polyhydric phenols such as phenol, cresol, xylenol, rose t-7' thylphenol, resorcinol, nonylphenol, hydroquinone, and catechol.

Epoxy compounds are usually used together with hardeners.

The curing agent is appropriately selected depending on the desired curable type.

Examples of the curing agent used in the composition of the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenebentamine, dipropylenediamine, diethylaminopyramine, hexamethylenediamine, menthendiamine, isophoronediamine, bis( 4-Amino-3-methyldicyclohexyl)methane, diaminodihexylmethane, bis(aminomethyl)cyclohexane, N-aminoethylpiperazine, 3.9-bis(3-aminopropyl)-2.4,8.
10-tetraoxaspiro(5.5)undecane, m-
Aliphatic polyamines such as xylylene diamine; aromatic polyamines such as metaphenylene diamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyl diphenylmethane; benzyldimethylamine, 2-
(dimethylaminomethyl)phenol, 2,4.6-}
Lis(dimethylaminomethyl)phenol, tetramethylguanidine, N,N'-dimethylbiverazine, triethylenediamine, 1,8-diazabiscyclo(5,4
．． 0) Secondary or tertiary amines such as undecene, triethanolamine, piperazine, pyrrolidine, polyamidoamine, fluoroboronoethylamine complex: methylnadic anhydride, dodecenylsuccinic anhydride, tetrahydride, phthalic anhydride, hexahydride Acid anhydrides such as phthalic anhydride, methylcondomethylenetetrahydrophthalic anhydride, chlorendic anhydride, ethylene glycol trimellitic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride; imidazole, 2-medylimidazole, 2 -ethyl-4-methylimidazole,
2-phenylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 1-benzyl-2-
Methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoedyl-2-undecylimidazole, 1-cyanoethyl-2- Methylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 2,4-diamino-6-{2゜-
Methylimidazolyl-(1')}monoethyl-S-}lyazine, 2.4-diamino-6-{2'-undecylimidazolyl(1'))monoethyl-S-}lyazine, 2.
4-diamino-6- (2'-ethyl-4゜-methylimidazolyl-(1')}-ethyl-S-triazine,
■-Cyanoethyl-2-ethyl-4-methylimidazole trimellitate, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-dodecyl-2-methyl-3-penzimidazolium chloride, 1,3 dibenzyl- Imidazole derivatives such as 2-methylimidazolium chloride: dicyandiamide or its derivatives;
Organic acid dihydrazide such as adipic acid dihydrazide; 3-
(p-chlorophenyl)-1,l-dimethylurea, 3-
Examples include urea derivatives such as (3,4-dichlorophenyl)-1,1-dimethylurea; polymerkabutane curing agents; methylol group-containing compounds such as phenol resins, urea resins, and melamine resins; polyisocyanates, etc. can.

In particular, when the composition of the present invention is prepared as a one-component type, the curing agent is preferably a latent curing agent such as a dicyandiamide compound.

Further, when the composition of the present invention is prepared as a photocurable type, examples of the curing agent include aromatic diazonium salts and sulfonium salts known as ultraviolet curable catalysts.

The amount of these curing agents used is usually such that the active hydrogen of these curing agents is equal to the epoxy group of the epoxy compound,
For example, epoxy group: active hydrogen = 1: 0.8-1.2
(equivalence ratio).

Furthermore, the composition of the present invention may use a curing accelerator as necessary, such as 2,4.6-}lis(dimethylaminomethyl)phenol, 2-(dimethylaminomethyl), 1,8-diazabisic. Examples include (5,4.0) undecene and its salts, tertiary amines such as adivic acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, dimethylbenzylamine, phenols, phosphines, imidazoles, and the like.

The amount of these curing accelerators used is determined depending on the type, curing conditions, etc.

The graphite fibrils, which are the second component of the composition of the invention, have a diameter (D) of 3.5 to 70 nm, preferably 7 to 25 nm, and a length (L) of at least 5 times the diameter D. In other words, those having a relationship of L/D>5 are used.

If the diameter D is less than 3.5 nm, the graphite fibrils are likely to scatter and are difficult to handle. Furthermore, if the diameter D exceeds 70 nm, no significant improvement in oil surface adhesion can be expected. In addition, the length is less than or equal to 5 times the diameter D, that is,
When L/D≦5, a sufficient effect of improving oil surface adhesion cannot be obtained. The preferred range of L/D is 102 to 104.

The graphite fibril consists of an outer region consisting of essentially continuous multilayers of regularly arranged carbon atoms and an inner core region, with the outer region of multilayers and the inner core region surrounding the cylindrical axis of the fipril. It is preferred that the inner core region is hollow or that the inner core region is comprised of multiple layers.
It is preferred that the inner core region contains less regular carbon atoms than the ordered carbon atoms of the lateral regions, that the ordered carbon atoms are graphitic, and that the inner core region has a diameter greater than about 2 nm.

Such graphite fibrils can be manufactured, for example, as follows. That is, suitable metal-containing particles,
For example, iron-, cobalt-, or nickel-containing particles using alumina as a support are mixed with a suitable gaseous carbon-containing compound, such as carbon monoxide, at a temperature of 850 to 1200°C and under a suitable pressure (for example, 10 atm), for example 1
It can be obtained by contacting for 0 seconds to 180 minutes. At this time, it is preferable that the dry weight ratio of carbon-containing compound/metal-containing particles is at least 100/1.

Graphite fibrils are made of the above-mentioned curable compound 10
It is preferably used in an amount of 0.1 to 30 parts by weight, more preferably 0.5 to 10 parts by weight, still more preferably 0.75 to 3 parts by weight.

The method of uniformly dispersing the graphite fifurls in the curable compound and other components of the composition to obtain a uniform composition is not particularly limited, and may be a conventional method, such as mixing using a three-roller. A method such as that is used.

The graphite fifryl used may be treated with a coupling agent, ultraviolet rays, or
The surface may be previously subjected to surface treatment using plasma or the like.

The graphite fifurls may also form intertwined aggregates in the compositions of the present invention.

Rubber can also be mixed into the composition of the present invention, if necessary. The rubber used is butadiene rubber,
Examples include styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-proprene rubber, isoprene rubber, chloroprene rubber, butyl rubber, and acrylic rubber. These rubbers may have functional groups such as carboxy groups, epoxy groups, and hydroxyl groups introduced therein as necessary. The method of compounding the rubber is not particularly limited, but when using a rubber having a functional group, it may be used after performing a preliminary reaction with a curable compound such as an epoxy compound. Furthermore, the form of the rubber is not particularly limited. In this way, by including rubber in the composition, toughness can be imparted to the obtained cured product, and adhesive strength can be improved.

Furthermore, the composition of the present invention may contain various additives, such as flexibility imparting agents, pigments, leveling agents, tackifiers, antifoaming agents, heat stabilizers, light stabilizers, and various fillers, as necessary. Agents, etc. can be blended as appropriate.

Further, a conductive or oil-absorbing filler such as conductive carbon black, graphite powder, carbon fiber, etc. may be added at the same time as the graphite fipril.

[Example] Bisphenol A-type epoxy compound with a tip 1 epoxy equivalent of 189 (Epicote 828; manufactured by Yuka Ciel Epoxy Co., Ltd.)
100 parts by weight, 8 parts by weight of dicyandiamide, 50 parts by weight of calcium carbonate (S330 manufactured by Nitto Funka Co., Ltd.), graphite fifuryl (llyperion catalyst)
sis inc. 3 parts by weight of N,N-dimethylbenzylamine (DMBAi manufactured by Wako Pure Chemical Industries, Ltd.) and 1 part by weight of N,N-dimethylbenzylamine (DMBAi manufactured by Wako Pure Chemical Industries, Ltd.) were mixed for 30 minutes at room temperature (20°C) using a three-roll roll to prepare a composition. Obtained.

2-4 and 1-5 In the same manner as in Example 1 above, the types and amounts of the curable compound (base resin and curing agent), graphite fipril, and additives were varied as shown in Table 1. Each adhesive composition was obtained by mixing.

The reagents shown in the table are as follows.

・Ancamine 161B (alicyclic polyamine): A・
Manufactured by C.I. Japan Limited, R-1309: Manufactured by ACR Co, epoxy resin/silica powder containing 30% acrylonitrile-butadiene rubber: AEROS I L-2 0 0, Manufactured by Nippon Aerosil Co., Ltd. Carbon black: Manufactured by Asahi Carbon, HS-500/Carbon fiber: Hicarboron A-6 0 0 0, diameter 7
μm, length 0. 5 mm Table 1 also shows the curing conditions for each composition.

, The following evaluation tests were conducted on each of the above compositions.
The results are shown in Table 2.

(1) Dispersibility Dispersibility when mixed using three rolls (0, good, ×
(Poor) (2) Presence or absence of fluidity of the fluid composition at room temperature (3) Presence or absence of stringiness The composition is visually observed to see if it pulls strings when lifted with a wooden spatula (4) Shape retention when applied Shape retention when applied on a vertical surface (○: good, ×: sagging) (5) Composition: Ease of pressing when the composition is placed on an adherend and crimped (
O: good; (however,
The composition used was prepared without adding a catalyst. ) (7) Oil surface adhesion 1.6X25X100mm, 0.8x25x200mm
Two steel plates were immersed in anti-rust oil (RL-44; manufactured by Idemitsu Kosan Co., Ltd.) and immediately stood vertically and left overnight to serve as adherends. After the composition was applied onto the adherend, they were pressed together, immediately held with clips, and cured at 180°C for 30 minutes or at 140°C for 60 minutes. The thickness of each composition layer was adjusted to 0.25 mm.

Next, tensile shear strength and T-peel strength were measured. The tensile speed was 5 m/m when measuring the tensile shear strength.
in. ．． The T-shaped peel strength was measured at 50 mm/min. For comparison, a steel plate whose surface had been cleaned was bonded with the same adhesive composition as above, and the tensile shear strength and T
The shape peel strength was measured and the results are shown in Table 2.

As is clear from the results shown in Table 2, the composition of the present invention contains a small amount of graphite fifurls in addition to the conventionally added oil-absorbing filler of carbon black or carbon fiber. By adding it, good oil surface adhesion can be obtained.

Furthermore, the addition of graphite fifryls imparts thixotropy and prevents sedimentation of the filler.

(Effects of the Invention) As explained above, the composition of the present invention has excellent oil surface adhesion, storage stability, and coating workability, and is suitable for adhesion of steel plates with oil surfaces such as hemming parts of automobiles. It is extremely useful for Furthermore, since the composition of the present invention contains graphite fiprils dispersed therein, it also has the advantage of improving the electrical conductivity of the adhesive.

Claims (1)

[Claims] An adhesive composition comprising a curable compound and graphite fibrils having a diameter of 3.5 to 70 nm and a length exceeding at least 5 times the diameter.