JP2004026070A - Method of adhering and sealing hem portion of vehicle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of adhering and sealing a hem portion of a vehicle body panel that prevents or decreases occurrence of blister at baking and hardening a body sealer due to air accumulation of the hemming adhesive when adhering (using the hemming adhesive) a circumferential hem portion of the vehicle body panel (an inner panel and an outer pane) and sealing (using a body sealer) a step at a hem superposed portion of the both panels. <P>SOLUTION: This method uses a hemming adhesive including 0.3 to 2 wt% of glass beads having the average grain size of 100 to 300μm for adhering a circumferential hem portion, and pressurizes a hemming portion, and uses a plastisol sealer for sealing a step. <P>COPYRIGHT: (C)2004,JPO

Description

表１中
注１）油化シエルエポキシ（株）製「エピコート８２８」
注２）ポッターズバロティーニ（株）製「Ｍ−７」（平均粒径２５０μｍ）
注３）同（株）製「Ｍ−１３」（平均粒径５０μｍ）
【００２６】
（２）プラスチゾルシーラー（Ｎｏ．Ａ〜Ｃ）
下記表２にＮｏ．ＡとＢの組成（重量部）および１５０℃熱時の破断強度（ｋＰａ）（ダンベル物性）を示す。
Ｎｏ．Ｃは、１５０℃熱時の破断強度が４０ｋＰａである市販ＰＶＣゾルシーラー：サンスター技研（株）製の「ペンギンシール＃１５７１」を使用。
【００２７】
【表２】

表２中、
注４）三菱レイヨン（株）製「ダイヤナールＬＰ３１０６」
注５）グリセリンベーストリオール／ＴＤＩのオキシムブロック体（分子量５
０００）
注６）富士化成（株）製「フジキュアＦＸＥ−１０３０」
【００２８】
（３）試験測定
Ｉ）上記（１）のヘミング接着剤（Ｎｏ．１〜３）を用いて下記の要領で接着クリアランスとかしめ強度を測定し、結果を下記表３に示す。
接着クリアランス
被着体：ＳＰＣＣ−ＳＤ鋼板（２５×１００×０．８ｍｍ）
ラップ代：１０ｍｍ
加圧時の厚み（鋼板＋接着剤＋鋼板）
剪断試験のテストピースを用い、加圧力（３０ＭＰａ）と加圧時の隙間を接着剤無しと接着剤有りにて測定し、その差を接着クリアランス（ｍｍ）とした。なお、許容基準値を０．０８ｍｍ以下とする。
接着クリアランス（ｍｍ）＝（接着剤有りの厚み）−（接着剤無しの厚み）
【００２９】
かしめ強度
アウターパネル：２５×７０×０．８ｍｍ（折返し部７ｍｍ）
インナーパネル：２５×１００×０．８ｍｍ
ラップ代：６ｍｍ
幅２５ｍｍのヘム形状試験片を用い、一定の加圧力（３０ＭＰａ）を加えた後、引張試験を行いかしめ強度（引き抜き強度）（ＭＰａ）とした。なお、許容基準値を０．８ＭＰａ以上とする。
【００３０】
ＩＩ）フクレ挙動と塗膜割れの評価（下記結果を表３に示す）
図１に示すように１００×３００ｍｍの鋼板１に、ヘミング接着剤（Ｎｏ．１〜３）２を塗布し、その上に２枚の１５×２２０ｍｍの鋼板３ａ，３ｂを載せて加圧力３０ＭＰａにてプレスする（この場合、エアー想定部面積を３０×７．５ｍｍに設定）。加熱硬化は１７０℃×２０分間で行なう。
【００３１】
次に鋼板１と鋼板３ａ，３ｂの合せ部（段差）に上記（２）のシーラー（Ｎｏ．Ａ〜Ｃ）を１ｍｍ厚で塗布し、１１０℃×１０分（昇温時間２５分）、次いで１４０℃×２０分で焼付硬化する。焼付硬化後のシーラーのフクレ挙動（フクレ直径）を測定する（なお、許容基準値を４ｍｍ以下とし、○：合格、×：不合格）。
【００３２】
さらに、シーラー塗布したテストピースに、自動車用中塗塗料を１５〜２０μｍ厚にて塗装し、１４０℃×２０分間で焼付硬化を行ない、塗膜割れの有無を調べる（○は割れ無し、×は割れ有り）。
【００３３】
【表３】

【００３４】
【発明の効果】
表３の結果より、本発明（実施例１〜３）によれば、低加圧力（３０ＭＰａ）でプレスした場合にも、接着クリアランスを適度に小さくし、よって、許容範囲のかしめ強度（仮止め効果）を得ることができ、しかも従来の、シーラーのフクレ発生や塗膜割れの問題点も一挙に解決しうることが認められる。
【図面の簡単な説明】
【図１】実施例のフクレ挙動と塗膜割れの評価試験において、鋼板に対しヘミング接着剤の塗布箇所を示す簡略図である。
【符号の説明】
１，３ａ，３ｂ：鋼板
２：ヘミング接着剤[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for bonding and sealing a hem portion of a body panel, and more particularly, to a hemming process in an automobile body assembly line, in which a peripheral hem portion of a body panel (an inner panel and an outer panel) is bonded (using a hemming adhesive). In order to prevent or reduce the occurrence of blisters during baking hardening of the body sealer due to the effect of the air accumulation of the above-mentioned hemming adhesive when sealing the step of the hem overlapping portion of both panels (using a body sealer). Related to the construction method.
[0002]
[Prior Art and Problems to be Solved by the Invention]
2. Description of the Related Art In a vehicle body assembly line of an automobile, a body panel (an inner panel and an outer panel) of a body part (a so-called lid part) such as a door, a trunk, a hood, and a sunroof cover is generally subjected to a hemming process. In particular,
i) apply a hemming adhesive to a peripheral hem portion of the outer panel,
ii) The inner panel is overlaid on this, the folded portion of the outer panel is clinched, and the hemming portion is pressed (pressed).
iii) Next, through an electrodeposition coating process, a body sealer is applied to the hem overlapping portion of both panels, and baking and curing are performed to seal the steps of both panels.
Thereafter, the baking and curing of the intermediate coating and the baking and curing of the top coating are performed as a post-process, and the operation is completed.
[0003]
By the way, conventionally, spherical particles such as glass beads, ceramics and hard alloys (stainless steel, titanium) are blended into the above-mentioned hemming adhesive as spacers for keeping the layer thickness constant. It penetrates into the panel surface at a stage and contributes to the temporary fixing effect (see Japanese Patent Application Laid-Open No. Hei 8-510698).
[0004]
On the other hand, as a body sealer, for example, a plastisol sealer obtained by dispersing polyvinyl chloride (PVC) or acrylic resin particles in a plasticizer is used.
However, the hemming adhesive is usually cured simultaneously by baking during the electrodeposition coating process, but due to the inclusion of the spherical particles, the adhesive clearance (gap) of the hem overlapping portion is increased, and the There is a strong tendency to generate air pockets at the filling site of the agent (of course, if the pressing of the hemming portion is performed as much as possible, the adhesive clearance can be reduced, but there is a limit in the process).
This air pocket expands during baking and hardening of the body sealer, causing blisters of the sealer, which often leads to a cracking phenomenon of a middle coat and / or a top coat.
[0005]
[Means for Solving the Problems]
Therefore, the present inventors made the above-mentioned adhesive clearance narrower, minimized the possibility of air accumulation and maintained an appropriate temporary fixing effect, and even if a certain amount of air remained, blistering of the body sealer did not occur. After intensive research on techniques that can prevent or reduce this, glass beads with a specific average particle size and amount are used as spherical particles to be mixed with the hemming adhesive, and pressed under a lower pressure condition than before. However, it has been found that a suitable adhesive clearance and a temporary fixing effect can be obtained, and that the addition of a thermosetting material to the body sealer can effectively prevent or reduce the occurrence of blisters if the hot strength is imparted. Thus, the present invention has been completed.
[0006]
That is, the present invention provides a method of bonding a peripheral hem portion to a vehicle body panel (an inner panel and an outer panel) by a hemming process and sealing a step of a hem overlapping portion of both panels.
A hemming adhesive containing 0.3 to 2% by weight of glass beads having an average particle diameter of 100 to 300 μm is used for bonding the peripheral hem portion, and the hemming portion is pressed by a press. Then, a plastisol sealer is applied to the step seal. The present invention provides a method for bonding and sealing a hem portion of a vehicle body panel, characterized by using:
[0007]
The hemming adhesive used in the present invention contains glass beads having an average particle diameter of 100 to 300 μm, preferably 140 to 250 μm, 0.3 to 2% (% by weight, the same applies hereinafter), preferably 0.5 to 1.5%. For example, a one-pack type epoxy adhesive composed of an epoxy resin (bisphenol-type epoxy resin, urethane-modified epoxy resin, acrylic rubber-modified epoxy resin, polyalkylene ether-modified epoxy resin, etc.) and a latent curing agent is typically shown. However, besides this, a polyurethane-based or acrylic-based adhesive containing glass beads as described above may be used.
[0008]
If the average particle size of the glass beads is less than 100 μm, sufficient crimping strength will not be exhibited, and if it exceeds 300 μm, the surface of the panel will be uneven.
If the content of the glass beads is less than 0.3%, the caulking strength is not exhibited, and if it exceeds 2%, the adhesive clearance cannot be sufficiently filled in the portion where the pressing force is low. Will trigger.
[0009]
As the body sealer used in the present invention, an ordinary plastisol sealer or, preferably, a thermosetting and heat-hardened one can be used, but a so-called PVC that does not generate dioxin during incineration is used. It is preferable that a thermosetting material is blended with an acrylic sol obtained by dispersing acrylic resin particles and a filler in a plasticizer, which is PVC-free, and has a breaking strength of 50 kPa or more when heated at 150 ° C. 3% or more is appropriate for the amount of the thermosetting material in the sealer).
[0010]
Examples of the acrylic resin particles include homopolymers of alkyl acrylate (eg, methyl, ethyl, butyl, 2-ethylhexyl as alkyl) or alkyl methacrylate (methyl, ethyl, butyl, lauryl, stearyl, etc. as alkyl) or It is a copolymer or a copolymer with other acrylic monomers (such as methacrylic acid, acrylic acid, and itaconic acid). Usually, the primary particles and / or the secondary particles in which the primary particles are aggregated have a particle size of 0. .1 to 100 μm are preferred.
Note that, as the acrylic resin particles, acrylic resin particles having a gradient structure in which the ratio of the constituent monomers changes continuously or in multiple stages from the core portion to the shell portion may be used. Such gradient type acrylic resin particles include, for example, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, ethylhexyl methacrylate, ethyl acrylate, n-butyl acrylate, sec. A mixture of at least one of -butyl acrylate and t-butyl acrylate [referred to as A monomer], at least one of methyl methacrylate and benzyl methacrylate and at least one of methacrylic acid, acrylic acid, itaconic acid and crotonic acid [mixture B In the polymerization, the above-mentioned monomer A and mixed B monomer are polymerized while changing the mixing ratio (ratio) in multiple stages or continuously. Can be prepared I (in this case, the component ratio of A monomer gradually decreases toward the shell portion from the core unit, the component ratio of the mixture B monomer is gradually increased toward the shell portion from the core part). In general, secondary particles having an average molecular weight of 1,000 to 2,000,000 and primary particles and / or secondary particles in which the primary particles are aggregated having a particle size of 0.1 to 100 μm may be used. As a commercial product, “Mitsubishi Rayon Co., Ltd.” "Dianal" is known.
[0011]
Examples of the filler include clay, calcium carbonate (heavy calcium carbonate, precipitated calcium carbonate, surface-treated calcium carbonate, etc.), magnesium carbonate, titanium oxide, calcined stone, barium sulfate, zinc white, silicic acid, mica powder, Examples include asbestos, talc, bentonite, silica, glass powder, red iron oxide, carbon black, graphite powder, alumina, shirasu balloon, ceramic balloon, glass balloon, plastic balloon, and metal powder.
Examples of the plasticizer include phthalic acid esters such as di (2-ethylhexyl) phthalate, butylbenzyl phthalate, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, diheptyl phthalate and butyl phthalyl butyl glycolate; dioctyl; Aliphatic dibasic acid esters such as adipate, didecyl adipate and dioctyl sebacate; polyglycol benzoic acid esters such as polyoxyethylene glycol dibenzoate and polyoxypropylene glycol dibenzoate; phosphoric acid such as tributyl phosphate and tricresyl phosphate Esters: alkyl-substituted diphenyl, alkyl-substituted terphenyl, partially hydrogenated alkyl terphenyl, aromatic process oil, pine oil It includes the hydrocarbons.
[0012]
The thermosetting material may be selected from, for example, the following groups (i) to (iv).
(I) Polyol [for example, polyoxyalkylene polyol (PPG), modified polyether polyol, polyether polyol containing polytetramethylene ether glycol; condensed polyester polyol, lactone polyester polyol, polyester polyol containing polycarbonate diol; other polybutadiene Based polyols, polyolefin based polyols and the like] and excess polyisocyanate compounds [for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, Dodecamethylene diisocyanate, 1,3-cyclopentane diisocyanate, 1,6- Xanthic diisocyanate (HDI), 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 4,4′-methylenebis (cyclohexyl isocyanate), methyl 2,4-cyclohexane diisocyanate, Methyl 2,6-cyclohexane diisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 5-naphthalenediisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, 2,4- or 2,6-tolylene diisocyanate , 4,4'-toluidine diisocyanate, dianidin diisocyanate, 4,4'-diphenyl ether diisocyanate, 1,3- or 1,4-xylylene diisocyanate, ω, ω'-diisocyanate-1,4-diethylbenzene, etc.] To obtain a urethane prepolymer having a terminal NCO group, and an appropriate blocking agent (for example, alcohols such as methanol, ethanol, propanol, butanol, and isobutanol; phenol, cresol, xylenol, p-nitrophenol, and alkylphenol). Phenols; active methylene compounds such as methyl malonate, dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, acetylacetone; acetamide, acrylamide, acetanilide, etc. Acid amides; acid imides such as succinimide and maleic imide; imidazoles such as 2-ethylimidazole and 2-ethyl-4-methylimidazole; lactams such as 2-pyrrolidone and ε-caprolactam; acetoxime and methylethylketoxime Oximes of ketones or aldehydes, such as cyclohexanone oxime and acetoaldoxime; other ethyleneimines, bisulfites, etc.) to block free NCO, thereby obtaining a blocked urethane prepolymer;
[0013]
(Ii) a blocked polyisocyanate compound obtained by blocking the NCO group of the polyisocyanate compound with the blocking agent;
[0014]
(Iii) polyhydroxy compounds [for example, polyalkylene glycol (polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, etc.); hexylene glycol, butylene glycol, propylene glycol, ethylene glycol, neopentyl glycol, triethylene glycol, pentanediol, hexanetriol Glycidyl ether type epoxy resin obtained by reacting an aliphatic polyhydric hydroxy compound such as glycerol] with epihalohydrin; and / or
(Iv) reacting a polyether polyol (for example, polyoxyalkylene polyol, modified polyether polyol, polytetramethylene ether glycol) with an excess of a polyisocyanate compound to obtain a urethane prepolymer having a terminal NCO group; A polyether urethane modified epoxy resin obtained by reacting an epoxy resin having at least one hydroxyl group (for example, diglycidyl ether of bisphenol A and diglycidyl ether of an aliphatic polyhydric alcohol).
[0016]
As the latent curing agent for the thermosetting material, a known curing agent may be appropriately used depending on the type of the thermosetting material, and is selected from, for example, the following groups (A) to (C).
(A) Those which can be activated at a temperature of 60 ° C. or higher to react with an NCO group or an epoxy group, for example, adipic dihydrazide, sebacic dihydrazide, isophthalic dihydrazide, 1,3-bis (hydrazinocarboethyl) -5 Dihydrazide compounds such as isopropylhydantoin, eicosane diacid dihydrazide, hydroquinone diglycolic acid dihydrazide, resorcinol diglycolic acid dihydrazide, 4,4'-ethylidenebisphenol diglycolic acid dihydrazide; dicyandiamide; 4,4'-diaminodiphenyl sulfone; imidazole, 2 Imidazole compounds such as -n-heptanedecyl imidazole; melamine; benzoguanamine; N, N'-dialkyl urea compounds; N, N'-dialkyl thiourea compounds; diaminodiphenyl Room temperature solid polyamine having a melting point of 60 ° C. or higher, such as methane, diaminobiphenyl, diaminophenyl, phenylenediamine, tolylenediamine, dodecanediamine, decanediamine, octanediamine, tetradecanediamine, hexadecanediamine, and hydrazide-based polyamine;
[0017]
(B) As the polyamine-based modifying compound, aliphatic polyamine (a) (for example, dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, dipropylaminoethylamine, dibutyl Aminoethylamine, trimethylhexamethylenediamine, diaminopropane, etc.) and a cyclic structure amine or aromatic polyamine (b) having at least one NH ₂ or NH group (for example, meta-xylylenediamine, 1,3-bis (aminomethyl) Cyclohexane, isophoronediamine, menthanediamine, diaminocyclohexane, phenylenediamine, toluylenediamine, xylylenediamine, diaminodiphenyl Methane, diaminodiphenylsulfone, piperazine, polyamines and monoamines such as N-aminoethylpiperazine, benzylamine and cyclohexylamine) and diisocyanate compound (c) (for example, isophorone diisocyanate, meta-xylylene diisocyanate, 1,3-bis (isocyanatomethyl) ) Cyclohexane, 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, 1,5-naphthylene diisocyanate, 1,4-phenylene diisocyanate, diphenylmethane-4,4′-diisocyanate, 2,2′-dimethyldiphenylmethane -4,4'-diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, etc.) (A) and amine (b) and epoxide compound (d) (polyphenols such as bisphenol A, bisphenol F, bisphenol S, hexahydrobisphenol A, catechol, resorcin, trihydroxybiphenyl, benzophenone, hydroquinone, and tetramethylbisphenol A) Glycidyl ether obtained by reacting epichlorohydrin with glyceryl ether; polyglycidyl ether obtained by reacting aliphatic polyhydric alcohols such as glycerin, neopentyl glycol, ethylene glycol, and polyethylene glycol with epichlorohydrin; p-oxybenzoic acid, oxynaphthoic acid Glycidyl ether esters obtained by reacting hydroxychlorocarboxylic acid with hydroxycarboxylic acid such as phthalic acid, isophthalic acid, tetrahydrophthalic acid, ene Polyglycidyl esters derived from polycarboxylic acids such as methylenetetrahydrophthalic acid, trimellitic acid, and polymerized fatty acids; glycidylaminoglycidyl ether derived from aminophenol and aminoalkylphenol; glycidylaminoglycidyl ester derived from aminobenzoic acid; Aniline, toluidine, tribromoaniline, xylylenediamine, glycidylamine derived from 4,4′-diaminodiphenylmethane; epoxidized polyolefin, glycidylhydantoin, glycidylalkylhydantoin, triglycidyl cyanurate, butyl glycidyl ether, phenylglycidyl ether, Monoepoxides such as alkylphenyl glycidyl ether, glycidyl benzoate and styrene oxide Reaction products;
[0018]
(C) As another polyamine-based modifying compound, one or more selected from the above-mentioned aliphatic polyamines, cyclic structure polyamines and aromatic polyamines and an epoxy compound (for example, one epoxy group per molecule) A phenol compound (for example, a phenol resin, a resol novolak resin, etc.) and / or a polyphenol compound (e.g., a phenol resin, a resole novolak resin, etc.) having at least two or more bisphenol-type epoxy resins, novolak-type epoxy resins, polyester-type epoxy resins, and polyether-type epoxy resins. Compounds in which a carboxylic acid compound (for example, adipic acid, sebacic acid, dodecanoic acid, azelaic acid, etc.) is reacted and the amino group is masked to be inactivated.
[0019]
In the present invention, a specific example in which a thermosetting material is added to the plastisol has been described. However, as the plastisol sealer used in the present invention, a plastisol component having a crosslinkable functional group (polyvinyl chloride, acrylic resin, or the like) is used. The breaking strength at break can also be improved.
[0020]
In such a plastisol sealer, if necessary, a moisture absorbent (calcium oxide, molecular sieves, etc.), a thixotropic additive (organic bentonite, fumed silica, aluminum stearate, metal soaps, castor oil derivatives, etc.), Stabilizer [2,6-di-t-butyl-4-methylphenol, 2,2-methylene-bis (4-methyl-6-t-butylphenol), nickel dibutyldithiocarbamate, etc.], curing accelerator (dibutyltin) Dilaurate, lead octylate, bisnas octylate and the like), solvents (high-boiling hydrocarbon solvents such as naphtha and paraffin) and the like may be appropriately selected and added.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
The hem portion adhesive seal method of the vehicle body panel according to the present invention uses the above-mentioned hemming adhesive and plastisol sealer, and is characterized in that it is pressurized under the above-mentioned low pressure tightening conditions, and is performed in the following procedure by a usual method. Can be implemented.
i) A hemming adhesive is applied to the outer hem portion of the outer panel in a string shape of 1 to 2 mmφ.
[0022]
ii) The inner panel is superimposed on this, and the folded portion of the outer panel is clinched and pressed (pressed). Here, the adhesive clearance measured under the conditions shown in Examples described later is set to 0.1 mm or less, preferably 0.01 to 0.08 mm, and the caulking strength (pulling strength) measured for the temporary fixing effect is also 0.1 mm. 8 MPa or more is observed.
[0023]
iii) Next, after performing a normal electrodeposition coating process (degreasing → chemical conversion treatment → electrodeposition coating → washing with water → baking hardening), a plastisol sealer is applied in an amount of about 1 mm to the hem overlapping portion of both panels, Baking and hardening are performed at about 120 ° C. for 15 minutes to seal the step between both panels. Here, no abnormality such as blistering or foaming of the sealer is observed.
Thereafter, baking of the intermediate coating and baking of the top coating are performed in the post-process.
[0024]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples.
Examples 1-3 and Comparative Examples 1-3
(1) Hemming adhesive (No. 1-3)
In Table 1 below, No. The compositions (parts by weight) of 1 and 2 are shown.
No. 3 is a commercially available adhesive containing 5% of glass beads having an average particle size of 250 μm: “Penguin Cement # 1063G” manufactured by Sunstar Giken Co., Ltd.
[0025]
[Table 1]

Note 1 in Table 1) "Epicoat 828" manufactured by Yuka Ciel Epoxy Co., Ltd.
Note 2) "M-7" manufactured by Potters Barotini Co., Ltd. (average particle size 250 μm)
Note 3) “M-13” (average particle size 50 μm) manufactured by the same company
[0026]
(2) Plastisol sealer (No. AC)
In Table 2 below, No. The compositions (parts by weight) of A and B and the breaking strength (kPa) at 150 ° C. heat (dumbbell physical properties) are shown.
No. C is a commercially available PVC sol sealer having a breaking strength of 40 kPa at 150 ° C. heat: “Penguin Seal # 1571” manufactured by Sunstar Giken Co., Ltd.
[0027]
[Table 2]

In Table 2,
Note 4) "Dianal LP3106" manufactured by Mitsubishi Rayon Co., Ltd.
Note 5) Oxime block of glycerin-based triol / TDI (molecular weight 5
000)
Note 6) "Fujicure FXE-1030" manufactured by Fuji Kasei Co., Ltd.
[0028]
(3) Test measurement I) Using the hemming adhesive (Nos. 1 to 3) of the above (1), adhesive clearance and swaging strength were measured in the following manner, and the results are shown in Table 3 below.
Adhesion clearance Substrate: SPCC-SD steel plate (25 x 100 x 0.8 mm)
Wrap fee: 10mm
Thickness when pressurized (steel plate + adhesive + steel plate)
Using a test piece for a shear test, the gap between the pressing force (30 MPa) and the pressure was measured with and without the adhesive, and the difference was defined as the adhesion clearance (mm). The allowable reference value is 0.08 mm or less.
Adhesion clearance (mm) = (thickness with adhesive)-(thickness without adhesive)
[0029]
Caulking strength Outer panel: 25 x 70 x 0.8 mm (turned part 7 mm)
Inner panel: 25 × 100 × 0.8mm
Wrap fee: 6mm
After applying a constant pressing force (30 MPa) using a hem-shaped test piece having a width of 25 mm, a tensile test was performed to obtain a crimping strength (pulling strength) (MPa). The allowable reference value is set to 0.8 MPa or more.
[0030]
II) Evaluation of blistering behavior and coating film cracking (the following results are shown in Table 3)
As shown in FIG. 1, a hemming adhesive (No. 1 to 3) 2 is applied to a 100 × 300 mm steel plate 1, and two 15 × 220 mm steel plates 3 a and 3 b are placed thereon, and a pressure of 30 MPa is applied. And press it (in this case, the assumed air area is set to 30 × 7.5 mm). Heat curing is performed at 170 ° C. for 20 minutes.
[0031]
Next, the sealer (No. A to C) of the above (2) is applied with a thickness of 1 mm to the joint (step) of the steel sheet 1 and the steel sheets 3a and 3b, 110 ° C. × 10 minutes (heating time 25 minutes), Bake hardens at 140 ° C for 20 minutes. The blistering behavior (blister diameter) of the sealer after baking and curing is measured (the allowable reference value is 4 mm or less, ○: pass, ×: reject).
[0032]
Further, a test piece coated with a sealer is coated with an intermediate coating for automobiles at a thickness of 15 to 20 μm, and is baked and cured at 140 ° C. for 20 minutes to check for cracks in the coating film (○: no cracking, x: cracking) Yes).
[0033]
[Table 3]

[0034]
【The invention's effect】
According to the results of Table 3, according to the present invention (Examples 1 to 3), even when pressed at a low pressing force (30 MPa), the adhesive clearance was appropriately reduced, and therefore, the allowable caulking strength (temporary fixing) was obtained. Effect) can be obtained, and the conventional problems of blistering of the sealer and cracking of the coating film can be solved at once.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a simplified diagram showing a location where a hemming adhesive is applied to a steel sheet in an evaluation test of blistering behavior and coating film cracking of an example.
[Explanation of symbols]
1, 3a, 3b: steel plate 2: hemming adhesive

Claims (5)

In the method of bonding the peripheral hem portion to the body panel (inner panel and outer panel) by the hemming process, and sealing the step at the hem overlapping portion of both panels,
A hemming adhesive containing 0.3 to 2% by weight of glass beads having an average particle diameter of 100 to 300 μm is used to bond the peripheral hem portion, and the hemming portion is pressed. Then, a plastisol sealer is used to seal the step. A method of bonding and sealing a hem portion of a vehicle body panel. The hemming part adhesive sealing method according to claim 1, wherein the hemming adhesive is a one-part heat-curable epoxy resin adhesive. The hem adhesive bonding method according to claim 1 or 2, wherein the plastisol sealer contains a thermosetting material and has a breaking strength at 150 ° C of 50 kPa or more when heated. The heme adhesive bonding method according to any one of claims 1 to 3, wherein the plastisol sealer is obtained by mixing a thermosetting material with an acrylic sol obtained by dispersing acrylic resin particles and a filler in a plasticizer. The hem portion adhesive seal method according to any one of claims 1 to 4, wherein an adhesive clearance is set to 0.1 mm or less in the hem overlapping portion, and a temporary fixing effect of a caulking strength of 0.8 MPa or more is provided.

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