JPS62109880A - Adhesive sheet having excellent lamination workability to metallic plate stained with oil - Google Patents

Abstract

PURPOSE:To obtain the titled adhesive sheet for automobile, etc., having excellent adhesivity and having an easily releasable releasing paper, by impregnating a substrate with an adhesive composed of an epoxy resin, a filler, etc., in a manner to protrude the edge of the substrate from the edge of the adhesive layer. CONSTITUTION:The objective adhesive sheet has a volume resistivity of 10<2>-10<12>OMEGAcm and a thickness of 0.1-3mm and is produced by applying an adhesive 1 composed mainly of an epoxy resin (e.g. a liquid or semi-solid resin containing long-chain alkyl as a main chain), a filler and a hardener to a substrate 2 provided with a releasing paper 4 in a manner to protrude the edge 3 of the substrate 2 from at least one edge of the adhesive layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an adhesive sheet used for oil-attached metal plates,
More specifically, the present invention relates to an adhesive sheet that has excellent adhesion to oil surfaces and is easy to apply to metal members, particularly steel plate members, to which oil is usually adhered, such as vehicle bodies such as automobiles, airplanes, and ships, home appliances, and Sendai type equipment.

[Conventional technology]

Traditionally, metal l? 4. Structures and the like are formed by welding or joining metal plates formed into a predetermined shape. These metal plates, especially steel plates, usually have oil such as rust preventive oil or press working oil attached to them. A thermosetting liquid adhesive is usually used to join such metal plates, and is cured by heating, such as by painting.

However, depending on the shape and location, it may be difficult to coat, and the adhesion to the oil surface may be poor.Also, the thickness of the coating film may not be constant, resulting in uneven adhesion, or additional sealing properties. There was a problem that the bonding became uneven and stable adhesion could not be achieved. Furthermore, due to the pressure applied during processing, excess adhesive may spill out, necessitating wiping off or the like, resulting in a marked deterioration in formability. In addition, it has a high volume resistivity, so electrodeposition coating,
It was not possible to perform welding, etc., and the parts where it could be used were sometimes limited.

(Problems to be Solved by the Invention) The problems to be solved by the present invention are to solve the above-mentioned difficulties of conventional adhesive sheets of this type. The object of the present invention is to solve each of the above-mentioned difficulties that arise when using an adhesive sheet.

[Means for solving problems]

The above problem is that the sheet is made by impregnating and integrating an epoxy resin, a filler, and a hardening agent into a base material, and an adhesive layer is required to improve the workability of pasting onto a metal plate with oil adhesion. This is achieved by using as an adhesive sheet a sheet having a structure in which the base material protrudes from at least one edge beyond the width of the adhesive sheet.

[Structure and operation of the invention]

The adhesive sheet of the present invention basically has the following structure. That is, it is made by impregnating a base material with an adhesive composition mainly composed of an epoxy resin, a filler, and a curing agent, and the base material protrudes from at least one edge beyond the width of the adhesive layer. It has the following configuration.

The adhesive sheet of the present invention is, for example, as shown in FIG. It also has a protruding portion (3) in at least one direction. Preferably, a release paper (4) is further provided. This release paper does not necessarily have to cover the entire surface of the base material (2), and may be provided on the adhesive composition decoy. In FIG. 1, the protruding portion is shown only on one side, but it is not necessarily limited to one side, and may protrude on either side.

In the present invention, the 1-boxy resin is particularly preferably (a)
Use a liquid or semi-solid epoxy resin having a long alkyl main chain, or a mixture of a liquid or semi-solid epoxy resin with a high molecular weight thermoplastic resin derived from bisphenol 8 and epichlorohydrin. As a result, it is possible to provide a strong adhesive sealing property even to a metal plate member to which oil has adhered. In addition, by adopting a structure in which the base material protrudes, the work of peeling off the release paper becomes easy, and therefore, the desired fixing properties are excellent.

When attaching this adhesive sheet to an oily metal plate, as shown in Figure 2, place the adhesive sheet at a predetermined position on the oily metal plate, and press the protruding IC base material with your hands as shown in 8. Peel off the release paper with one hand.

As the epoxy resin constituting the adhesive sheet used in the present invention, a normal epoxy resin can be used, but preferably (a) a liquid or semi-solid epoxy resin having a long alkyl chain, or (b) a liquid or semi-solid epoxy resin that can be used at room temperature. A mixture of liquid or semi-solid epoxy resin with a high molecular weight thermoplastic resin derived from bisphenol and epichlorohydrin is used, and since the chain constituent molecules of these epoxy resins are hydrophobic groups, they are not easily resistant to fats and oils. It has good compatibility with steel sheets and contributes to improving initial adhesion with oil film steel sheets. Also, since it contains relatively long chain components, the resin has a high cohesive force and excellent sheet form performance.

The long alkyl main chain has about 5 to 50 carbon atoms, preferably about 8 to 30 carbon atoms. Such resins include epoxy resins produced by reacting epichlorohydrin with polymers such as polyethylene glycol, polypropylene glycol, and α/ω-glycol, which is a block copolymer of ethylene oxide and propylene oxide; - Epoxy resin derived from reaction of ylide: dimer acid,
Examples include epoxy resins derived from trimer acids, unsaturated higher fatty acids, or esters thereof.

Among the above epoxy resins, epoxy resins derived from long chain dimer acids having 10 to 20 carbon atoms are preferably used, and examples include epoxy resins derived from linoleic acid dimer and epichlorohydrin. When these resins are used, a particularly good effect on oil surface adhesion can be obtained, and an adhesive sheet with excellent water resistance, chemical resistance, etc. can be obtained.

Note that it is possible to use a normal epoxy resin together with the above-mentioned epoxy resin having a long alkyl main chain in a proportion of 50% or less of the total weight. The high molecular weight thermoplastic resin derived from bisphenol A and epichlorohydrin used in the present invention has an average molecular weight of at least 10.000 or more including repeating units represented by the following structural formula: However, this average molecular weight is a number average molecular weight, and is a value determined by gel permeability chromatography using polystyrene as a reference material. A typical commercially available thermoplastic resin is Phenoxy Resin (trade name) manufactured by Union Carbide.
82-123 repeating units per molecule, softening point 212
F, average molecular fi25. ooo~35,000). These high molecular weight thermoplastic resins derived from bisphenol A and epichlorohydrin are
When used, it is mixed with a liquid or semi-solid epoxy resin.

At this time, the thermoplastic resin is usually used in an amount of 5 to 70% by weight, preferably 10 to 40% by weight, and is rarely used alone. The liquid or semi-solid epoxy resin used in combination is not particularly limited, but those having the above-mentioned long alkyl chains are usually not used.

The liquid or semi-solid state of the epoxy resin used in the present invention usually exhibits properties at room temperature. The curing agent is preferably one that is stable at room temperature and exhibits activity at high temperatures, particularly nitrogen-containing compounds that decompose at high temperatures to produce at least one active hydrogen-containing amine, such as monourea,
It is preferable to use volurea, hydrazide, thiourea, etc. Specifically, 3-(Pchlorophenyl)-
Examples include 1,1-dimethylurea and 2,4-bis(NN-dimethylcarbamide).

Of course, it is also possible to use other curing agents such as acid anhydrides, imidazoles, imidacillins, etc.
Specific examples of these include phthalic anhydride, maleic anhydride, dodecylsuccinic anhydride, hexahydrophthalic anhydride,
Methyl nadic anhydride, pyromellitic anhydride, dichlorosuccinic anhydride, benzophenonetetracarboxylic anhydride,
Chlorendic anhydride, 2-methylimidazole, 2
-Ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 2-tamatylimidazole, 2-isopropylimidazole, 2,4-dimethylimidacillin, 2-phenyl-4 -methylimidazole, 2-methylimidacillin, 2-ethyl-4-methylimidacillin,
2-phenylimidacilline, 2-undecylimidacilline, 2-heptadecyl imidacilline, 2-ethylimidacilline, 2-isopropylimidacilline, 2,4-dimethylimidacillin, 2-phenyl- Examples include 4-methylimidacillin.

Depending on the type and amount of these curing agents, the adhesive sheet will be almost cured when the electrodeposition coating is heated and baked (even if it is not completely cured at this point, it will be heated and baked during the intermediate coating and top coating processes in the subsequent process). It can be set as appropriate depending on the conditions of heating and baking.

The general amount is 0.5 to 130 parts by weight, preferably about 5 to 50 parts by weight, per 100 parts by weight of the epoxy resin.

As the filler used in the present invention, any filler that has been conventionally used in this type of adhesive sheet can be used, such as clay, talc, calcium carbonate, silica,
In addition to fillers such as barium carbonate and asbestos, fillers that provide electrical conductivity can also be used. In particular, in the present invention, by using a conductive filler, it is possible to perform electrodeposition coating, spot welding, or electrodeposition coating after spot welding. Such conductive fillers include silver, palladium,
Examples include metal powders such as copper, aluminum, iron, and nickel, and inorganic substances other than metal powders such as carbon black and graphite. The amount of filler used is usually about 5 to 300 parts by weight per 100 parts by weight of epoxy resin, but in the case of conductive fillers, it varies depending on the type, shape, particle size, etc. of the conductive filler, but usually epoxy resin It is used in a proportion of about 10 to 700 parts by weight, preferably about 20 to 200 parts by weight, per 100 parts by weight. Further, the shape, particle diameter, etc. may be appropriately selected and determined from a wide range, and examples thereof include granular, acicular, and scaly shapes.

In the case of granules, the particle size is 0.1 to 400μ, preferably 0.1μ to 400μ.
Approximately 5 to 200μ, if needle-like, the diameter (shorter side) is approximately 0.
The thickness is about 1 to 500μ, preferably about 0.5 to 300μ, and the aspect ratio is about 5 to 200, preferably about 10 to 150. In the case of scales, the thickness is about 0.1 to 500μ, preferably 0.1 to 300μ, and the aspect ratio is 5 to 20.
0, preferably about 10 to 150.

In the present invention, when using conductive fillers as fillers, these conductive fillers are mixed into the above-mentioned resin composition to form an adhesive sheet with a volume resistivity of 1.
It is preferable that it is 0.012 Ωcm or less. 10'2Ωc
When it is higher than rg, it is very difficult for the electrodeposited film to adhere when electrodeposition is performed, especially at the boundary between the adhesive sheet and the metal plate, which may cause rust afterward.

When performing spot welding, the spot welding conditions, that is, welding current, welding time, pressurizing force, electrode shape, etc., determine whether spot welding is possible, but the volume resistivity of the contact sheet If it is higher than 10'2 Ω crn, it is not preferable because it requires stricter spotting conditions, although it depends on the jt thickness and viscosity of the adhesive sheet. Therefore, in the present invention, the volume resistivity is 1011 Ωcar or less, the sheet thickness is 0.1 to 3 Ω, and the epoxy resin (7) is heated at 30°C (D
Viscosity I
load) is desirable.

When applying an adhesive sheet using a conductive filler and performing electrodeposition painting or spot welding, for example, in the case of electrodeposition painting, the adhesive sheet is applied to a metal plate in advance, processed as necessary, and then Electrodeposition coating is applied, and then the adhesive sheet is cured when the coating is heated and baked. In the case of spot welding, the adhesive sheet is sandwiched between two steel plates and welding processing such as spot welding is performed. give Furthermore, the above electrodeposition coating can also be performed after spot welding.

In addition to the above-mentioned components, various compounding agents can be added to the adhesive resin composition of the present invention as necessary. For example, in order to further improve heat resistance,
-naphthylamine, diphenyl-P-phenylenediamine, ditertiarybutyl-4-methylphenol, P-
Stabilizers and anti-aging agents such as phenylphenol, calcium stearate, and dilauryl thiodipropionate can be added, and diesters, ester gums, alkyd resins, coumaron resins, etc. can be added for the purpose of further improving adhesiveness. Other coloring agents may also be added. These compounding ingredients may be about 5 to 300 parts by weight per 100 parts by weight of the epoxy resin. To obtain the adhesive resin sheet used in this invention, first, a curing agent and a filler are added to the epoxy resin, Add various other additives as necessary and mix at room temperature or at a temperature that does not cause curing using a mixing pot, various kneaders, two or three mixing rolls, etc. to prepare a resin composition.

Next, this composition is applied in an uncured or semi-cured state to a substrate layered with release paper using a coater such as a roll coater or a knife coater, various press molding machines, or an extrusion molding machine. It is sufficient to form the sheet into a sheet with a width smaller than the width of the sheet.

If the product is made as described above, the base material will protrude from both sides, but in some cases, it may be cut at the resin-coated surface and used with the base material protruding from only one side.

In addition to the above-mentioned purposes, the base material used in the present invention has the following properties:
~ It has the advantage of improving shape retention or reinforcing effect, and suitable base materials are those made of porous materials such as cheesecloth, coarse sheets of various materials, nets, and woven and nonwoven fabrics of various materials. .

〔Example〕

The present invention will be explained below with reference to Examples.

However, the numbers indicate heavy items.

Example 1 75 parts of Epicoat #871 (dimer acid-modified epoxy resin manufactured by Yuka Shell Co., Ltd.) and 25 parts of Epicoat #828 (El bisphenol A type liquid epoxy resin manufactured by Yuka Shell Co., Ltd.) were melted and mixed in a melting pot. A sticky composition was obtained. To 100 parts of this composition were added 2 parts of dicyandiamide (an epoxy resin curing agent made by Nippon Carbide Co., Ltd.), 3 parts of 3-(P-chlorophenyl)-1.1 dimethyl urea (an epoxy resin curing agent made by Kanyo Biochemical Co., Ltd.), and talc powder. 75 parts were blended and kneaded using a normal mixing roll to obtain a resin composition. Next, the resin composition heated to 100°C using a roll coater was applied to a release paper base (vinylon cheesecloth #100).
: manufactured by Kuraray RL) with a width narrower than the width of the base material,
The adhesive sheet is coated to a thickness of 4 mm and is impregnated with the base material for 1 q.

Next, 0 and 8 coated with anti-rust oil used as automobile parts.
Attach the above adhesive sheet to a steel plate with a thickness of 100 nm by first pressing the base material onto the metal with one hand and peeling off the release paper with the other hand. In this way, the initial fixation is easy, and there is no contamination of the hands from the resin, and the workability is excellent. The adhesive is cured by heating at 180°C for 20 minutes in the baking process of electrodeposition coating, and then baked at 140°C for 20 minutes each in the intermediate coating and top coating processes to completely cure and provide excellent adhesive strength. An adhesive seal was formed.

Example 2 75 parts of Epicoat #871 (dimer acid-modified epoxy resin manufactured by Yuka Shell Co., Ltd.) and 25 parts of Epicoat #828 (bisphenol Δ type liquid epoxy resin manufactured by Yuka Shell Co., Ltd.) were melted and mixed in a melting pot. 11 for a dense composition. To 100 parts of this composition, 2 parts of dicyandiamide (epoxy resin curing agent manufactured by Nippon Carbide Co., Ltd.), 3-(P-chlorophenyl)
3 parts of -1.1 dimethyl urea (an epoxy resin curing agent manufactured by Kanyo Biochemical Co., Ltd.) and 75 parts of talc powder were blended and kneaded using a normal mixing roll to obtain a resin composition.

Next, using a roll coater, the resin composition heated to 100°C was coated on a release paper base material (vinylon cheesecloth #100; Kuraray Co., Ltd. ￥A) in a width of 0.4 m narrower than the width of the base material, and a thickness of 0.4 m. An adhesive sheet was obtained which was impregnated and integrated with the base material.

Next, 0 and 8 coated with anti-rust oil used as automobile parts.
The above-mentioned adhesive sheet was attached to a steel plate having a thickness of aq.m by first pressing the base material onto the metal with one hand and peeling off the release paper with the other hand.

In this way, initial fixation was easy, and the workability was excellent without contaminating hands with the resin. Then, similar steel plates were stacked to form a joint, and the tip diameter of the electrode was 4.8 m, Tl
a Flow 1a 7800A, Pressure fJ190h/, -
, f, spot welding was performed under the spot conditions of 8 cycles of energization time, nuggets were formed and welding was successful. The coating is subjected to normal degreasing and chemical conversion treatment, and the adhesive is cured by heating at 180°C for 20 minutes in the baking process of electrodeposition coating, and then heated at 140°C for 20 minutes in the intermediate coating and top coating processes.
Baking was carried out for 0 minutes to completely cure and form an adhesive seal with excellent adhesive strength.

[Brief explanation of drawings]

FIG. 1 shows an example of an adhesive sheet used in the method of the present invention,
FIG. 2 is a drawing for explaining a method of bonding using this. [11...Epoxy resin adhesive (2)
...Base material (3) ...Protruding part (4) ...
...Release paper (5) ...Oil-adhered metal plate (or more)

Claims (8)

[Claims] (1) In an adhesive sheet formed by impregnating a base material with an adhesive composition mainly composed of an epoxy resin, a filler, and a curing agent, the base material protrudes from at least one edge beyond the width of the adhesive layer. An adhesive sheet with excellent workability when attached to oil-adhered metal plates. (2) The epoxy resin is a liquid or semi-solid epoxy resin having a long alkyl main chain, or a liquid or semi-solid epoxy resin is blended with a high molecular weight thermoplastic resin derived from bisphenol A and epichlorohydrin. An adhesive sheet according to claim 1, comprising: (3) The adhesive sheet according to claim 1 or 2, wherein the filler is a conductive filler. (4) The viscosity of the above epoxy resin at 30°C is 1 x 10
The adhesive sheet according to claim 3, which has a poise of ^3 to 1 x 10^7 poise (high-performance flow tester, nozzle diameter 1.0 mm, 10 kg/load). (5) The adhesive sheet according to any one of claims 3 to 4, wherein the conductive filler is made of a metal powder or/and an inorganic substance such as carbon black or graphite. (6) The volume resistivity of the above adhesive sheet is 10^2 to 10^
The adhesive sheet according to any one of claims 3 to 5, which has a resistance of 1^2 Ωcm. (7) The adhesive sheet according to any one of claims 3 to 6, wherein the adhesive sheet has a thickness of 0.1 to 3 mm. (8) The adhesive sheet according to any one of claims 1 to 7, wherein the base material is a woven fabric or a nonwoven fabric.