JPH02233745A - Adhesive composition for hemming part of automotive body - Google Patents

Abstract

PURPOSE:To obtain an adhesive composition excellent in flexibility, bonding durability, rust preventing properties, etc., and useful for hemming parts of automotive bodies by blending a vinyl chloride-based polymer with a plasticizer, epoxy resin, latent curing agent and filler at a specific ratio. CONSTITUTION:An adhesive composition, consisting of (A) 100pts.wt. vinyl chloride-based polymer, (B) 20-100pts.wt., preferably 30-80pts.wt. plasticizer (e.g. di-2-ethylhexyl phthalate), (C) 10-80pts.wt., preferably 15-60pts.wt. epoxy resin (e.g. glycidyl ester type epoxy resin), (D) 3-40pts.wt., preferably 5-30pts.wt. latent curing agent (e.g. dicyandiamide) and (E) 30-100pts.wt., preferably 30-80pts. wt. filler (e.g. calcium carbonate) and obtained by finely dispersing the total amount of the components (D) and (E) in 20wt.% component (B) and the total amount of the component (C), then kneading and blending the resultant dispersion with a plastisol consisting of the total amount of the component (A) and the residual component (B).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive composition suitable for filling hemming portions of automobile bodies.

[Problems to be solved by conventional techniques and inventions] In recent years, improving the durability of automobiles and extending the lifespan of automobiles has become a major social need from the viewpoint of resource conservation. The key to extending the lifespan of a vehicle is to protect it from rust. In particular, there are parts of the car body that are difficult to apply anti-rust treatment to due to its structure, such as door hemmings, inner hood end hemmings, and rocker panels.Since these parts have a bag structure, moisture from rainwater etc. When water or moisture enters the vehicle, it tends to accumulate, causing rust and shortening the lifespan of the vehicle.

Conventionally, paste-like epoxy resin adhesives have been mainly used for these parts. That is, as shown in Fig. 1, adhesive 3 is applied to the edge of the exterior plate 1, and the edge of the interior plate 2 is aligned with this, and then the edge of the exterior plate 1 is folded back, press-formed, and bent. The portion 1a is formed to form a hemming structure. Panels with this hemmed structure are
It is assembled by spot welding for temporary fixing, and then subjected to chemical conversion treatments such as degreasing, cleaning, and acid treatment along with the entire car body, and then subjected to the electrodeposition painting process, where the adhesive is cured and fixed in a paint baking oven during this process. ．． However, with paste-like epoxy resin adhesives, the adhesive tends to fall off or scatter, and the processing liquid is contaminated during the degreasing, cleaning, acid treatment, etc. In addition, spot welding for temporary fixing inevitably leaves dents, which is unfavorable for the appearance of the vehicle body. Furthermore, after the epoxy resin adhesive is baked and hardened in the electrodeposition coating process, it is highly rigid, and dynamic stress such as vibrations during the car body assembly process or while driving can cause the ends of the cured epoxy resin adhesive to be coated with the electrodeposition coating. There is a problem in that it peels off from the edge 4a or cracks, and water and moisture enter from there, causing rust. Furthermore, epoxy resin adhesives are expensive and have problems in terms of economic efficiency.

Therefore, recently, hemming adhesives (1) can be used to temporarily fix panels with a hemmed structure formed by coating and molding by means other than temporary fixing spot welding, such as short-time low-temperature preheating, and (2) are used in the next process. There is no falling off, scattering, or contamination of the processing solution during degreasing, cleaning, acid treatment, etc., and (3) it has sufficient adhesive strength and flexibility after baking and hardening in the electric M coating process.
and (4) there is a desire for something that satisfies all of the following: sufficient long-term adhesive durability and rust prevention. Of course, it goes without saying that it is essential that the coating also satisfies appropriate viscosity for coating operations, storage stability, fixability to oil-surface steel plates, etc.

A composition comprising vinyl chloride plastisol mixed with an epoxy resin and its curing agent has been proposed as a material for a hemming adhesive that satisfies the above requirements. For example, JP-A-55-48272 and JP-A-62-146973. The former is a reaction product (solid) of vinyl chloride polymer with carboxyl group/plasticizer/liquid epoxy resin/aliphatic polyamine and polycarboxylic acid or anhydride.
The latter is a composition consisting of a vinyl chloride polymer/synthetic rubber/plasticizer/dialkyl peroxide/liquid epoxy resin/specific polycarboxylic acid hydrazide (curing agent)/filler. It is a composition consisting of. However, the former does not allow for a hardened state for temporary temporary fixing, and the latter does not allow for a hardened state to be used for temporary fixing, and the latter is used in the assembly process of automobile body hoods, roofs, and doors. This relates to mastic adhesives used for bonding for the purpose of damping vibrations and improving rigidity.It has a high viscosity at room temperature, has excellent workability in heated discharge application, has good adhesion to rust-preventive oil surfaces mvi, and has excellent properties in chemical conversion treatment processes. This product has improved shower resistance and conformability that will hold the mastic in place if it is subjected to vibrations during transport in an uncured state before moving on to the electrodeposition coating baking process where the mastic adhesive is cured, and eliminates the need for spot welding. It is not something that can be temporarily fixed, and it is far from something that satisfies all of the above requirements.

In order to solve the above problems as an adhesive for hemming, the present inventors focused on the fact that vinyl chloride polymer plastisol gels when heated at low temperature for a short time, and developed a vinyl chloride polymer plastisol adhesive composition. As a result of intensive research, it was discovered that the above problem could be solved by blending vinyl chloride polymer/plasticizer/epoxy resin/latent curing agent/filler in a specific ratio, leading to the completion of the present invention. Ta. (Means for Solving the Problems) The present invention comprises (A) 100 parts by weight of a vinyl chloride polymer, (
B) 20-100 parts by weight of plasticizer, (C) 1 part of epoxy resin
0-80 parts by weight, (D) 3-40 parts by weight of latent curing agent,
(E) An adhesive composition for a hemming part of an automobile body, characterized in that it contains 30 parts by weight of a filler. Furthermore, the present invention includes (A) 100 parts by weight of a vinyl chloride polymer, (B) 20-100 parts by weight of a plasticizer, (C) 10-80 parts by weight of an epoxy resin, and (D) 3-40 parts by weight of a latent curing agent. (H) 30-1.00 parts by weight of filler, the total amount of latent curing agent and filler being finely dispersed in 20% by weight of plasticizer and the total amount of epoxy resin. The present invention provides an adhesive composition for a hemming part of an automobile body, which is then kneaded and blended into a vinyl chloride polymer plastisol consisting of the entire vinyl chloride polymer and the remaining plasticizer. The vinyl chloride polymer (A') of the present invention may be one normally used for plastisol, and is produced by emulsion polymerization, suspension polymerization, solution polymerization, etc. of vinyl chloride alone or with other copolymerizable monomers. You can also use things. The plasticizer (B), which is a component of the adhesive of the present invention, is not particularly limited as long as it can be used for vinyl chloride polymers, but examples include di-n-butyl phthalate and di-n-phthalate. Phthalic acid plasticizers such as octyl, di-2-ethylhexyl phthalate (DOP), diisooctyl phthalate, octyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, di-2-ethylhexyl isophthalate, di-2-ethylhexyl adipate (D.O.
A) Fatty acid ester plasticizers such as di-n-decyl adipate, diisodecyl adibate, di-2-ethylhexyl azelaate, dibutyl sebacate, di-2-ethylhexyl sebacate, tributyl phosphate, tri-2 phosphate -Phosphate ester plasticizers such as ethylhexyl, 2-ethylhexyldiphenyl phosphate, and tricresyl phosphate; epoxy plasticizers such as epoxidized soybean oil and epoxidized tall oil fatty acid-2-ethylhexyl; Use one type or a mixture of two or more types.

The amount of plasticizer used is 20 to 100 parts by weight, preferably 30 to 80 parts by weight, based on 100 parts by weight of the vinyl chloride polymer.

If the amount of plasticizer is less than 20 parts by weight, the adhesive after heat curing will be hard and will not have flexibility, and if it exceeds 100 parts by weight, the cohesive force of the adhesive after heat curing will be low and the adhesive force will be reduced. It is not suitable as an adhesive composition of the present invention.

As the epoxy resin (C) of the present invention, an epoxy resin having an average of two or more epoxy groups in one molecule, which is used as a component of ordinary epoxy resin adhesives, is used. Examples of such epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, novolac epoxy resins, polyfunctional phenol epoxy resins, and various halogenated epoxy resins. Further, diglycidyl ether compounds obtained by the reaction of resorcinol and epihalohydrin, glycidyl ester type epoxy resins, polyglycol type epoxy resins, cycloaliphatic epoxy resins, hydantoin type epoxy resins, glycidyl amine type epoxy resins, etc. can also be used. . Epoxy resins can be used alone or in combination of two or more types.

The amount of epoxy resin used is 10''-80 parts by weight, preferably 15-6 parts by weight, per 100 parts by weight of the vinyl chloride polymer.
It is 0 parts by weight. If the amount is less than 10 parts by weight, the adhesive force will be insufficient, and if it exceeds 80 parts by weight, the adhesive will become too hard after being heated and hardened, resulting in loss of flexibility. Next, as the (D) latent curing agent used in the present invention, those commonly used as curing agents for epoxy resins are used. Examples include guanidine derivatives, triazine derivatives, 4,4'-diaminodiphenylsulfone, acid hydrazide compounds, imidazole compounds, N,N'-dialkyl urea derivatives, and N,N'-dialkylthiourea derivatives. The amount used is 3 to 40 parts by weight, preferably 5 to 40 parts by weight, per 100 parts by weight of the vinyl chloride polymer.
It is 30 parts by weight. If it is less than 3 parts by weight, the adhesive strength will not be developed due to insufficient curing, and if it exceeds 40 parts by weight, the adhesive after heat curing will become hard and brittle.

The filler (E) used in the present invention includes calcium carbonate, barium carbonate, magnesium carbonate, calcium sulfate,
Examples include carbonates or sulfates of alkaline earth metals such as barium sulfate or magnesium sulfate, silica, clay, titanium oxide, aluminum powder, and the like. During its use,
30 to 100 parts by weight of vinyl chloride polymer
Parts by weight, preferably 30 to 80 parts by weight. If it is less than 30 parts by weight, the cohesive force of the adhesive after heat curing is insufficient,
If the amount exceeds 100 m parts, the adhesive after heat curing becomes too hard and its flexibility is impaired.

Furthermore, in addition to the above-mentioned components, various other additives such as stabilizers, mackerel-proofing pigments, thixotropic agents, etc. can be added to the composition of the present invention. Stabilizers include metal soaps (e.g. calcium stearate, aluminum stearate, etc.), inorganic acid salts (e.g. dibasic phosphites,
dibasic sulfate, etc.) and organometallic compounds (e.g., diptyltin dilaurate, dibutyltin malate, etc.). As anti-rust pigments, chromates (e.g.
Strontium chromate, barium chromate), basic lead sulfate, lead cyanamide, etc. Examples of the thixotropic agent include fine silica, organic bentonite, and ultrafine calcium carbonate. Further, when the adhesive composition contains water, it is also possible to add and mix a relatively small amount of powder such as calcium oxide, magnesium oxide, silicon oxide, etc. as a water adsorbent. Furthermore, colorants such as carbon black and red iron can also be optionally added.

The adhesive composition of the present invention can be obtained by kneading the above-mentioned components using a kneading machine typified by a three-roll mixer, a kneader mixer, a paddle mixer, a planetary mixer, a disk bar mixer, etc., by conventional means.

In particular, the total amount of latent hardener and filler used in the plasticizer
The adhesive composition of the present invention is obtained by finely dispersing the adhesive composition into a vinyl chloride polymer plastisol consisting of the entire vinyl chloride polymer and the remaining plasticizer. , which further solves the above problems and is more effective and useful for hemming automobile bodies. The latent curing agent and filler, which are mainly solid powders, are finely dispersed in an effective amount of plasticizer and epoxy resin, and then these are compatibilized in vinyl chloride polymer plastisol or vinyl chloride polymer particles. This seems to be caused by getting inside.

In this case, when a stabilizer or antirust pigment is added, it is preferable to finely disperse it together with the latent hardener and filler.

For fine dispersion, it is preferable to use a three-roll, kneader mixer, or disper mixer.

The composition of the present invention is particularly excellent as an adhesive for the automobile industry, particularly for hemming automobile bodies, but it can also be applied to various industrial uses as a sealant, paint, etc. in addition to being used as an adhesive.

〔Effect of the invention〕

The composition of the present invention can (1) temporarily fix panels with a hemmed structure by coating and forming C by means other than subso welding for temporary fixing, such as short-time low-temperature preheating, and (2) degreasing in the next step. It does not fall off, scatter, or contaminate the processing solution during cleaning, acid treatment, etc., and (3) has sufficient adhesive strength and flexibility after baking and hardening, and (4) has sufficient long-term adhesive durability and rust prevention. Since it satisfies all of the following, it is suitable as a hemming adhesive.

〔Example〕

EXAMPLES Next, the present invention will be explained by examples, but the present invention is not limited to these examples.

The test and evaluation method was as follows.

(1) Storage stability of viscosity The viscosity was measured using a capillary extrusion type viscometer at 35°C and a shear rate of 6.
The value was taken as the value at 2 sec-'. Storage stability is determined by a viscosity change of 30% after holding the adhesive composition at 40°C for 7 days.
If it falls within this range, mark it as O, and if it exceeds 30%, mark it as ×.
That's it.

(2) Adhesive strength: Using an oil-faced steel plate (SPC-O steel plate) coated with anti-corrosion oil,
Heat cured at 150°C for IO minutes and at 170°C for 20 minutes, and the shear adhesive strength and peel adhesive strength were determined according to JIS standards.
K6850, 23°C according to JIS K6854
It was measured with The adhesive strength when cured at 150°C for 10 minutes was used as a measure of temporary fixing property.

(3) Apply flexible adhesive to oil surface steel plate 1 5 0 x 2 5 x 1
After coating in the shape of mm, the steel plate was cured by heating at 170°C for 20 minutes, and the steel plate was bent at an angle of 90° at room temperature using a mandrel with a diameter of 1 inch. In this case, the case where the cured adhesive layer did not crack was rated O, and the case where it cracked was rated ×.

(4) Adhesion durability After holding the heat-cured test piece at 170'C for 20 minutes in (2) above at 50°C and 95% Rll for 30 days,
The adhesive strength was measured at 23°C, and the case where the strength was 80% or more of the initial strength was rated O, and the case where it was less than 80% was rated x.

(5) Rust prevention After applying the adhesive of the present invention to the lower part of the exterior plate 1 at the hemming part of the automobile body shown in Figure 1.2 using a coating gun,
The interior board 2 was pressed against it, and the lower end of the exterior board 1 was bent and caulked. Thereafter, this was heated at 150° C. for 10 minutes to heat and harden the adhesive, and then the protruding portion from the edge 2a toward the temporary interior direction was removed and electrocoated. Baking conditions are 17
The temperature was 20 minutes at 0°C. The hemming model thus obtained was subjected to a rust prevention test. Rust prevention is 5% Na at 50°C.
One cycle was immersed in an E aqueous solution for 4 hours, air-dried at 80'C for 2 hours, and left at room temperature for 2 hours.
A case where the occurrence of rust at the interface between the steel plate and the bonded layer after the cycle was slight was rated as ○, and a case where it was marked was rated as ×.

Examples 1 to 4 and Comparative Examples 1 to 2 Predetermined parts by weight of the raw materials shown in Table 1 were added, kneaded, and defoamed to obtain adhesive cutting compositions. In this case, the latent curing agent, filler, stabilizer, anticorrosion pigment, 20% by weight of the plasticizer used and the epoxy resin were blended and finely dispersed using a three-roll roll to form component (1), while vinyl chloride A vinyl chloride polymer plus disol consisting of a polyvinyl chloride polymer and a residual plasticizer was prepared in a Planecree mixer to obtain a component ([[)]. The component (It) is then placed in a planetary mixer containing the component (It).
After blending and kneading 1), blending and kneading a thixotropic agent,
Degassed under reduced pressure. The results of various tests are shown in Table 2.

As shown in Table 2, it was confirmed that the adhesive composition of the present invention shown in the Examples satisfied the characteristics required for a hemming adhesive.

(Hereafter, margin)

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the structure of an automobile body hemming part using the adhesive of the present invention, and FIG. 2 is a perspective view thereof. l...temporary exterior 1a...bending part 2...
・Interior board 2a...Edge 3...Adhesive

Claims (2)

[Claims] (1) (A) 100 parts by weight of vinyl chloride polymer, (B)
20-100 parts by weight of plasticizer, (C) epoxy resin 10-
80 parts by weight, (D) 3-40 parts by weight of latent curing agent, (E
) An adhesive composition for a hemming part of an automobile body, characterized in that it contains 30 to 100 parts by weight of a filler. (2) A vinyl chloride polymer is produced by finely dispersing the total amount of the latent curing agent and filler into 20% by weight of the plasticizer and the total amount of the epoxy resin, and then the total amount of the vinyl chloride polymer and the remaining plasticizer. The adhesive composition for a hemming part of an automobile body according to claim 1, which is formed by kneading and blending into plastisol.