JP2002338949A - Sealant composition, sealant, and laminate structure containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealant composition improved in adhesion to a coating film and a sealant, and to provide a laminate structure containing the same. SOLUTION: There are provided a sealant composition containing a lowly hygroscopic resin and a metal powder, a steel sheet wherein the composition constitutes a sheet or a seam, a sealant that seals the seam on the steel sheet, and a laminate structure containing a coating film on the sealant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sealing material composition having improved coating adhesion, a sheet obtained therefrom,
The present invention relates to a planar sealing material such as a tape and a strap, and a laminated structure including the same.

[0002]

2. Description of the Related Art Vehicles such as automobiles and trucks have discontinuous seams (seams) formed by laminating metal steel sheets. Such seams are usually used for rust prevention and design purposes. Various sealants are used and sealed. One example of a common non-planar overlap-type seam is a roof ditch formed in the front-back direction of a vehicle by bending and overlapping side edges of a vehicle roof panel and a side panel. This roof ditch has a U-shaped groove, and also has a role of collecting water and the like therein to promote drainage.

[0003] The sealing material is supplied as a liquid or solid material according to the requirements of construction. For example, in the automotive industry, seams in steel plates are often sealed using liquid plastisols. However, when the sealing material is in a liquid state, there are portions where the application is difficult. In such a case, it is necessary to use a sealing material (for example, a sheet, a tape, a strap, or the like) having a certain shape that exhibits adhesiveness.

The sealing material thus formed is disclosed in US Pat. No. 5,086,088, Japanese Patent Application Laid-Open No. 9-50 / 90.
For example, these sealing materials include an acrylic component in which a nitrogen atom is present in a molecule, and a thermosetting epoxy-containing material.

[0005] However, when the acrylic component contains a nitrogen atom as described above, the polarity generally increases, and as a result, the affinity of the sealing material for water tends to increase, and the water absorption tends to increase. When the sealing material seals the seam of the steel sheet in a state of absorbing the moisture, and thereafter, the coating is applied, the heat treatment after the coating increases the volume of the moisture, foams and expands. As a result, peeling between the sealing material and the seam of the steel sheet, breaking inside the sealing material,
The sealing material may be lifted. Such peeling, destruction, and lifting cause poor adhesion of the sealing material to the steel sheet and cause poor paint appearance.

[0006] In order to improve such a problem caused by water absorption of the sealing material, Japanese Patent Publication No. 9-505095 discloses a sealing material containing a photo-copolymer having low affinity for moisture together with a thermosetting epoxy-containing material. Has been disclosed. However, in the sealing material disclosed herein, the epoxy-containing material is compatible with the photo-copolymer, and the photo-copolymer is applied so as to be applied to a low energy adherend such as an oil-coated steel sheet. Is selected. Therefore, there is a problem that the paint adheres only insufficiently to such a sealing material.

Japanese Patent Application No. 11-140204 discloses a radiation-polymerizable vinyl material containing a vinyl monomer exhibiting a specific range of solubility parameters as a homopolymer and a sealing material containing a thermosetting epoxy-containing material. . The purpose of this sealing material is to control the polarity of the sealing material within a certain range to suppress water absorption and to increase the adhesion to a paint film.

On the other hand, recently, a coating film having high weather resistance has been required. With such a coating film, the load such as baking at high temperature and aging with hot water immersion becomes more severe than before, but even in such a case, it is possible to obtain a sealing material with good adhesion to the coating film. desirable.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sealing material composition having further improved adhesion to a coating film. A further object of the present invention is to provide a sealing material formed into a flat shape such as a sheet, a tape or a strap obtained from such a sealing material composition, and a laminated structure using such a sealing material. It is.

[0010]

According to the present invention, there is provided a sealing material composition comprising a low moisture absorbing resin and metal powder. Such a sealing material composition does not cause poor appearance after coating due to moisture and has high adhesion to a coating film. According to another aspect of the present invention, there is provided a sealing material formed into a flat shape selected from the group consisting of a sheet, a tape and a strap, comprising the above-mentioned sealing material composition. Such a sealing material is easily applied to an adherend, and is simultaneously cured when the coating film is cured to provide a strong structure with the adherend. Further, according to another aspect of the present invention, the steel sheet includes a steel sheet forming a seam, the sealing material formed into a flat shape and sealing the seam on the steel sheet, and a coating film on the sealing material. A laminated structure is provided. In such a structure, the appearance of the coating film is good, and the adhesion between the steel plate, the sealing material, and the coating film is very good.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Low Hygroscopic Resin The sealing material composition of the present invention contains a low-hygroscopic resin that is melt-flowable and thermosetting. As such a resin, conformability of the sealant material composition (conformability)
In addition to flexibility and flexibility, a mixture of a thermoplastic resin contributing to low hygroscopicity and a thermosetting resin contributing to ultimate strength and heat resistance, or an epoxy-modified thermoplastic resin may be used. Specifically, the low hygroscopic resin is a mixture of a relatively low-polarity polyvinyl-based component and a thermosetting resin such as an epoxy resin, a mixture of a polyester resin and a thermosetting resin such as an epoxy resin, and epoxy-modified. Thermoplastic resin. Such a low-hygroscopic resin comprising a mixture of a polyvinyl component and a thermosetting resin is disclosed in, for example, Japanese Patent Application No. Hei.
1-140204 and Tokuhyo Hei 9-505095
No., published in Japanese Unexamined Patent Publication No. Further, a low hygroscopic resin composed of a mixture of a polyester resin and a thermosetting resin, for example,
It is described in JP-A-9-505335. Further, a low hygroscopic resin composed of an epoxy-modified thermoplastic resin is described in, for example, Japanese Patent Application No. 2000-308146. As used herein, the term “melt fluidity and thermosetting” refers to fluidity at a temperature equal to or higher than the softening point of the thermoplastic resin component and lower than the thermal activation temperature of the thermosetting resin component. It is a resin that is thermoset when the activation temperature is exceeded. Also, the term “low moisture absorption”
The resin is 0.2% at 35 ° C. and 80 RH% relative humidity.
It means having a saturated water absorption of not more than mass%.

Polyvinyl Component In a mixture of a polyvinyl component and a thermosetting resin useful as a low-hygroscopic resin for the sealant composition of the present invention, the polyvinyl component is, for example, a solubility parameter when a homopolymer is used. Is preferably a polymerization product of a monomer containing a vinyl monomer having a value of 10 to 14 (cal / cm ³ ) ^0.5 . The “solubility parameter” is defined by the following equation.

[0013]

(Equation 1)

In the above formula, Δe _i is the evaporation energy of each atom or functional group constituting the homopolymer, and Δv
_i is the volume of each atom or functional group constituting the homopolymer. For details on the definition of the solubility parameter, see Polymer Engineering and Science, February 197.
4, Vol.14, No.2, "A Method for Estimating Boththe
Solubility Parameters and Molar Volumes of Liqui
d ", by Robert F. Fedors.

It is important that the vinyl monomer component exhibiting the above homopolymer solubility parameter preferably accounts for 50 to 100% by mass of the entire polyvinyl component. This is because such a content makes it possible to achieve a desirable mixture of the polyvinyl-based component, a thermosetting resin such as an epoxy resin, and a component for curing the same.
Further, it is desirable that the polyvinyl component has a solubility in water of not more than 0.2% by mass at 25 ° C. Thereby, moisture resistance can be imparted to the sealing material composition.

Specifically, monomers for such a polyvinyl component include 2-phenoxyethyl acrylate, benzyl acrylate, phenyl acrylate, phenylethyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, tricyclo [ 5.2.1.0 ^2,6 ] decanyl (meth) acrylate or the like can be used alone or in combination. More preferably, 2-phenoxyethyl acrylate, benzyl acrylate or phenyl acrylate or a combination thereof can be used. The above-mentioned polycarbonate components were obtained from Osaka Organic Chemical Company under the name of "Biscoat # 192" and "Biscoat # 1".
60 "under the trade name.

As a monomer for the polyvinyl-based component, a vinyl monomer other than the above-mentioned vinyl monomer can be used in combination. Examples of the vinyl monomer that can be used in combination include (meth) represented by 2-ethylhexyl acrylate, butyl acrylate, and ethyl acrylate.
Alkyl acrylate, or isobornyl (meth) acrylate, glycidyl (meth) acrylate,
Examples thereof include hydroxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, (meth) acrylic acid, 2-methoxyethyl (meth) acrylate, and vinyl acetate.

The polyvinyl component is desirably contained in an amount of 40 to 250 parts by mass with respect to 100 parts by mass of the thermosetting resin. If the amount of the polyvinyl-based component is less than 40 parts by mass, it becomes difficult to form the sealing material composition into a fixed shape such as a sheet, and the sealing material tends to become brittle. On the other hand, when the amount of the polyvinyl-based component exceeds 250 parts by mass, the thermosetting sealing material is not sufficiently crosslinked, and tends to be inferior in heat resistance and final sealing performance.

By polymerizing the above-mentioned monomer, a certain shape and, if necessary, further tackiness can be imparted to the sealing material composition. When the sealing material has adhesiveness, positioning of the sealing material becomes easy. Also,
It is particularly convenient if the sealing material composition is formed into a sheet, tape or strip form, which is convenient for handling.

The polymerization of the monomer can be carried out by radiation polymerization. The polymerization is carried out in the presence of a polymerization initiator which generates radicals by radiation such as ultraviolet rays. Examples of suitable polymerization initiators include 2,2-dimethoxy-1,2-
Diphenylethan-1-one, which is commercially available from Ciba Geigy as "Irgacure (TM) 651".

Curable Resin In a mixture of a polyvinyl component useful as a low hygroscopic resin and a thermosetting resin, the curable resin is, for example, a thermosetting epoxy-containing material. This material can contribute to improving the final sealing characteristics and heat resistance of the sealing material composition. Epoxy-containing materials that can be used are epoxy resins containing in their molecule at least one oxirane ring polymerizable by a ring opening reaction. Such epoxy-containing materials are broadly referred to as "epoxides" and include monomeric and polymeric epoxides, which may be aliphatic, cycloaliphatic or aromatic. On average, such epoxy-containing materials have 2 per molecule.
Epoxy groups, preferably two or more epoxy groups. Such materials are specifically called polyepoxides and also include epoxy-containing materials with an epoxy functionality of slightly less than 2.0, for example 1.8.
The average number of epoxy groups per molecule is defined as the number obtained by dividing the number of epoxy groups in the epoxy-containing material by the total number of epoxy molecules. The polymer epoxide includes a linear polymer having an epoxy group terminal (for example, diglycidyl ether of polyalkylene glycol) and a polymer having a skeleton of oxirane (for example, polybutadiene polyepoxide). The molecular weight of the epoxy-containing material may vary from about 58 to 100,000. Also, mixtures of various epoxy-containing materials can be used, if desired.

Suitable thermosetting epoxy-containing materials include, among others, bisphenol A epoxy resin, bisphenol AD epoxy resin, bisphenol F epoxy resin, phenol-novolak epoxy resin, cresol-novolak epoxy resin, and alicyclic ring. Heterocyclic epoxy resin such as formula epoxy resin, triglycidyl isocyanate, hydantoin epoxy, hydrogenated bisphenol A
Type epoxy resin, propylene glycol-diglycidyl ether copolymer, aromatic or aliphatic epoxy resin such as pentaerythritol-polyglycidyl ether copolymer, epoxy resin obtained by the reaction of alicyclic carboxylic acid and epichlorohydrin, Spiro ring-containing epoxy resin, glycidyl ether type epoxy resin which is a reaction product of o (ortho) -allyl-phenol novolak compound and epichlorohydrin, bisphenol A
A glycidyl ether type epoxy resin which is a reaction product of a diallyl bisphenol compound having an allyl group at the ortho position of each hydroxyl group of the type and epichlorohydrin can be exemplified.

Thermosetting agent The low moisture absorbing resin usually contains a thermosetting agent for curing the thermosetting resin. Preferably, the thermosetting agent is configured to be thermally activated such that the sealant composition cures upon exposure to a suitable heat source at a suitable time. That is, this thermosetting agent has a latent thermosetting property at room temperature, and is only thermally activated by heating to control the thermosetting of the epoxy-containing material. Suitable thermosetting agents include, but are not limited to, those listed below, such as dicyandiamide, organic acid hydrazides, acid anhydrides, salts of Lewis acids or Bronsted acids, imidazoles or urea derivatives. Triamine and the like can be mentioned. If necessary, such thermosetting agents may be used in combination.

More specifically, as an organic acid hydrazide used as a thermosetting agent, adipic dihydrazide is typical. Typical examples of the acid anhydride include phthalic anhydride, trimellitic anhydride and pyromellitic anhydride. Representative examples of the Lewis acid or Bronsted acid salt include monoethylamine of boron trifluoride and piperidine of boron trifluoride. Examples of imidazoles include 2,4-diamino-6- [2′-methylimidazole- (1 ′)]-ethyl-s-triazine,
Typical are 2,4-diamino-6- [2'-methylimidazole- (1 ')]-ethyl-s-triazine-isocyanurate, 2-phenyl-4-benzyl-5-hydroxyethylimidazole and nickel imidazole phthalate. It is. Representative examples of the tertiary amine such as a urea derivative include 3-phenyl-1,1-dimethylurea and 3-p-chlorophenyl-1,1-dimethylurea.
Of the above-mentioned thermosetting agents, tertiary amines such as imidazoles and urea derivatives are usually rarely used alone. These compounds can be used together with dicyandiamide, organic acid hydrazide or acid anhydride to perform the function of an accelerator.

Polyester Resins In a mixture of a polyester resin useful as a low hygroscopic resin for the sealant composition of the present invention and a thermosetting resin, preferred polyester resins are those which are solid at room temperature. Preferred polyester resins are from about 7,500 to 200,000, more preferably about 1
Between 0000 and 50,000, most preferably about 15,
It has a number average molecular weight of 000 to 30,000.

The polyester resin useful in the present invention contains a reaction product of a dicarboxylic acid (or a diester derivative thereof) and a diol. Dicarboxylic acids (or derivatives thereof) are saturated fatty acids having 6 to 12 carbon atoms (including those branched or unbranched or forming a ring with 5 to 6 carbon atoms) and / or 8 to 15 carbon atoms. It may be an aromatic acid having two carbon atoms. Examples of suitable fatty acids are succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, 1,1
It includes 2-dodecandioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 2-methylsuccinic acid, 2-methylpentanedioic acid and 2-methylhexanedioic acid. Suitable aromatic acids are terephthalic acid,
Examples include isophthalic acid, phthalic acid, 4,4'-benzophenone dicarboxylic acid, 4,4'-diphenylmethane dicarboxylic acid, 4,4'-diphenylthioether dicarboxylic acid, and 4,4'-diphenylamine dicarboxylic acid. Preferably, the structure between the two carboxylic acids in the diacid contains only carbon and oxygen, and this structure is preferably a phenylene group. As the diacid, a blend of diacids may be used.

The diols include branched, unbranched and cyclic aliphatic diols having 2 to 12 carbon atoms. Examples of suitable diols are ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,3-
Butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,6-hexanediol, cyclobutane-1,3di (2′-ethanol),
Includes cyclohexane-1,4-dimethanol, 1,10-decanediol, 1,12-dodecanediol and neopentyl glycol. Long chain diols such as poly (oxyalkylene) glycols having alkylene groups with 2 to 9, preferably 2 to 4 carbon atoms may be used. Further, a blend of diols may be used as the diol.

In the mixture of the polyester resin and the thermosetting resin, the same thermosetting resin and thermosetting agent as those used in the polyvinyl component and the thermosetting resin can be used. The mixing ratio of the polyester resin and the thermosetting resin may be the same as in the case of the mixture of the above-mentioned polyvinyl component and the thermosetting resin.

Epoxy-Modified Thermoplastics Epoxy-modified thermoplastics are also useful as low moisture-absorbing resins for the sealant compositions of the present invention. As the epoxy-modified thermoplastic resin, an ethylene-glycidyl (meth) acrylate copolymer is preferable. This ethylene-glycidyl (meth) acrylate copolymer is disclosed in JP-A-9-137028 and JP-A-10-37028.
As disclosed as a component of an adhesive and a hot melt composition in JP-A-316955, it is obtained by epoxidizing polyethylene and is usually obtained by copolymerization of ethylene and glycidyl methacrylate.
As a result, the ethylene-glycidyl (meth) acrylate copolymer is composed of an ethylene portion and a glycidyl (meth) acrylate portion.

The ethylene-glycidyl (meth) acrylate copolymer is desirably constituted so that the monomer weight ratio of ethylene to glycidyl (meth) acrylate is in the range of 50:50 to 99: 1. Ethylene-glycidyl (meth) acrylate copolymers containing ethylene exceeding the upper limit tend to make it difficult to impart desired mechanical strength and durability to the cured product. Conversely, ethylene-glycidyl (meth) acrylate copolymers containing ethylene below the lower limit tend not to achieve the desired low hygroscopicity.

Another typical example of an epoxy-modified thermoplastic resin is an epoxidized styrene-based thermoplastic resin. This epoxidized styrene-based thermoplastic resin is, for example, a block copolymer having a hard segment made of polystyrene and a soft segment made of epoxidized polybutadiene and imparting rubber elasticity to the elastomer. Alternatively, epoxidized polyisoprene can be used instead of, or in conjunction with, epoxidized polybutadiene.

Usually, the glass transition temperature (Tg) of an epoxy-modified styrenic thermoplastic resin is as very low as -70 to -50 ° C. At this time, the cured product of the thermosetting composition of the present invention has an approximately Durability at low temperatures up to -30 ° C (particularly vibration durability) can be enhanced. As a result, this epoxy-modified styrenic thermoplastic resin is very advantageous for sealing applications where stress is repeatedly applied even at low temperatures, for example, for roof ditch sealing of automobiles as described above. In addition, in sealing applications for roof ditch of automobiles, the cured product is cured by an automobile paint (for example, an organic solvent-based acrylic paint or an organic solvent-based alkyd paint) and a cation, due to a styrene portion and an epoxy group of the epoxidized styrene-based thermoplastic resin. It comes into close contact with the electrodeposited automotive steel sheet.

One example of such an epoxy-modified styrene-based thermoplastic resin is styrene-epoxidized butadiene-
A styrene copolymer and a styrene-epoxidized isoprene-styrene copolymer. In either case, the epoxidation is performed by epoxidizing the unsaturated bonds of the conjugated diene.

[0034] The epoxy-modified thermoplastic resin contains the same curing agent as the above low hygroscopic resin.

Low Hygroscopicity of Resin The excellent low hygroscopicity derived from the use of the above-mentioned thermoplastic resin such as a polyvinyl component and a polyester resin facilitates quality control of the sealing material composition. It is not necessary to store the sealant composition in a desiccator or with a desiccant to prevent exposure to, for example, winter condensation. Even if the sealing material composition is left under high-temperature and high-humidity conditions before thermosetting of the thermosetting resin, the sealing material composition does not substantially absorb moisture. Referring to the automobile manufacturing industry as an example, when a line is closed on a holiday, the sealant composition applied to the automobile parts remains attached without thermosetting the thermosetting resin. Particularly during a long vacation in the summer, etc., the sealing material composition may be exposed to high temperature and high humidity for a long period of time. Even if the operation is restarted and the automobile parts with the sealing material composition are passed through the heating booth and the painting booth, the disadvantage that the sealing material composition expands is substantially eliminated. This is because, as described above, the sealing material composition does not absorb moisture and does not expand its volume even when heated. Therefore, the sealing material composition of the present invention does not absorb moisture, maintains adhesion to discontinuous portions such as seams even when heated, and can cover and protect it.

Metal Powder The sealing material composition of the present invention is characterized by containing metal powder. When the metal powder is exposed on the surface of the sealing material, the metal powder acts to improve the adhesion to the coating film formed on the sealing material. Examples of the metal powder include aluminum powder, nickel powder, and silver powder, and aluminum powder is preferably used from an economic viewpoint. The average particle size of the metal powder is preferably 10 to 100 μm.
It is. If it is less than 10 μm, the metal powder is not exposed from the surface of the sealing material, and the effect of the present invention may not be obtained. On the other hand, if it exceeds 100 μm, the surface smoothness of the sealing material formed into a sheet or the like is impaired. This is because the desired appearance may not be obtained. The metal powder is usually spherical particles, but other forms such as flakes, fibers, rods, etc. can be applied as long as the effects of the present invention are exhibited.

The metal powder may be uniformly dispersed throughout the sealing material, but the metal powder may be contained only in the surface layer of the sealing material formed into a sheet or the like. Such a case is preferable because the cost of the sealing material can be reduced. Such a sealing material can be obtained by a method described in detail below.

Further, at least one barrier layer made of a nonwoven fabric, a resin such as polyester and nylon such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), a metal or the like is provided inside or on one or both surfaces of the sealing material. You may be. Thus, even if air bubbles enter the sealing material from the discontinuous surface of the sealing portion during heating and melting, the barrier layer can capture the air bubbles inside the sealing material. That is, it is possible to prevent bubbles from appearing on the surface of the sealing material, and to maintain and improve the preferable appearance of the coating film. In addition, the barrier layer can support the sealing material and improve the handleability thereof. However, the barrier layer is not limited to the above. Irradiation such as an electron beam may be applied to the surface of the sealing material to provide a crosslinked structure on the surface and form a barrier layer.

Other Ingredients Further, the sealing material composition of the present invention may contain, if necessary, a filler made of a powder such as calcium carbonate, silica, alumina or talc; a microsphere filler such as silica; A plasticizer made of an acid derivative, an adipic acid derivative or a liquid rubber, an antioxidant, a surfactant, or an antifoaming agent made of polydimethylsiloxane may be contained.

Method for Producing Sealant The sealant composition of the present invention is preferably a sheet,
It is used as a sealing material formed into a flat article such as a tape and a strap. FIG. 1 shows a cross-sectional view of one embodiment of the sealing material of the present invention. For example, when the sealing material composition is a mixture of a polyvinyl component and a thermosetting resin, the sealing material 1 includes a monomer for the polyvinyl component and a heat A sealing material 1 in which a metal powder 3 is dispersed in a low hygroscopic resin 2 can be obtained by sandwiching a mixture containing a curable resin and a metal powder, and then polymerizing the above monomer with radiation such as ultraviolet rays. it can. When the sealing material composition is a mixture of a polyester resin and a thermosetting resin or an epoxidized thermoplastic resin, the activity of the curing agent is higher than the softening point of the polyester resin or the thermoplastic resin. The sealing material 1 can be obtained by compounding and molding the sealing material composition of the present invention at a temperature lower than the formation temperature by an appropriate device such as an extruder. FIG. 2 is a cross-sectional view of a sealing material containing metal powder only in the surface layer. Such a sealing material is a co-extruded sealing material composition of the present invention containing metal powder and a sealing material composition not containing metal powder, or a sealing material containing metal powder, and containing metal powder. Laminate with no sealing material by appropriate means such as heat lamination,
It can be manufactured by an appropriate means such as. Also,
FIG. 3 is a cross-sectional view of one embodiment of a sealing material including a barrier layer. Such a sealing material can be obtained by laminating the sealing material 1 and the barrier layer 4 by an appropriate means.

Use of Sealing Material Composition and Sealing Material The sealing material composition of the present invention and a sealing material formed from the same can be particularly suitably used for sealing automotive steel sheets. FIG. 4 is a cross-sectional view of one embodiment of a laminate including a steel sheet sealed with the sealing material of the present invention, a sealing material, and a coating film. For example,
The sealing material 1 of the present invention is applied to a discontinuous portion such as a seam of the steel plate 7 to which the cationic electrodeposition coating has been applied.
Precuring is performed at a temperature of 00 ° C. or higher, and then a coating film 6 of an amino alkyd type paint is applied and baked, whereby a laminate 5 is obtained. Normally, the amino alkyd type paint is first applied with a first-layer coating as an intermediate baking coating, baked at a temperature of, for example, 140 ° C., and then a second-layer coating is applied. It is baked at the temperature. In addition, the sealing material composition and the sealing material of the present invention are not limited to automotive applications, but can be used in other applications such as architectural applications.

[0042]

In the following, the present invention will be further described with reference to examples. In the examples, unless otherwise indicated.
Parts and percentages are by weight. Example 1 First, the following vinyl monomer and polymerization initiator, that is, (1) 15 parts of n-butyl acrylate (nBA)
And (2) 85 parts of 2-phenoxyethyl acrylate (2-POEA) and 0.04 parts of Irgacure (Irg
acure) 651 "(trade name, manufactured by Ciba Geigy) in a transparent jar and mixed. Thereafter, the jar was purged with nitrogen, and then the mixture was irradiated with ultraviolet light using an ultraviolet light source having a maximum intensity in an ultraviolet region having a wavelength of 300 to 400 nm to partially polymerize the vinyl monomer. The irradiation of the ultraviolet rays is performed at a power density of 1.76 mW / cm ² , and the partial polymerization has a viscosity of about 3,000 mW / cm ^2.
Pa. s.

Next, while continuously stirring this partial polymerization product, the following components were used: (4) 0.1 part of “Irgacure 651”, (5) 3 parts of glycidyl methacrylate (GMA), (6) 50 parts of "Epicoat 1001" having an epoxy equivalent of about 500 (manufactured by Yuka Shell Epoxy Co., Ltd.); (7) 30 parts of "Epicoat 828" having an epoxy equivalent of about 190 (oiling shell epoxy) (8) 6 parts of dicyandiamide, (9) 2
Parts of 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine (“2-MZ
A) (Shikoku Chemicals), (10) 100 parts of aluminum powder ("AC-2500", manufactured by Toyo Aluminum Co., Ltd.) having an average particle size of about 45 m was added to prepare a sealing material precursor composition.

Next, silicone having a thickness of 50 μm
A pair of treated polyethylene terephthalate (PE
T) Prepare a film, between these PET films
The sealing material composition precursor prepared as described above
To a thickness of 0.5 mm. Then purple above
External light is placed on each PET film, and two PET
UV light is applied to the sealing material composition precursor through the film.
Then, the vinyl monomer was polymerized. At this time, purple
The energy density of external radiation is 1,000 mJ / cm ^Twoso
there were. 0.5m when removing two PET films
m of a sheet-shaped sealing material is obtained.
Was.

Example 2 In place of (1) 15 parts of n-butyl acrylate and (2) 85 parts of 2-phenoxyethyl acrylate in Example 1, 40 parts of isooctyl acrylate (I
OA), using 60 parts of isobornyl acrylate,
Further, (6) 50 parts of “Epicoat 1” in Example 1 were used.
In place of “001” and (7) 30 parts of “Epicoat 828”, 35 parts of a hydrogenated epoxy-containing material (epoxy equivalent = 190, trade name “RXE21”, manufactured by Yuka Shell Epoxy Co.) was used. (10) A sheet-like sealing material was produced in the same manner as in Example 1, except that 60 parts of aluminum powder was used instead of 100 parts of aluminum powder.

Example 3 (11) 50 parts of a thermoplastic polyester resin (trade name "Dynapol S1402", manufactured by Huls) and (1)
2) 40 parts of "Epicoat 1001", (13) 7 parts of dicyandiamide, (14) 3 parts of "2-MZA", and (15) 50 parts of aluminum powder ("AC-25
00 ") was uniformly mixed to prepare a sealing material composition. This sealing material composition was put into an extruder and processed into a sheet having a thickness of 0.5 mm to produce a sheet-shaped sealing material.

Comparative Example 1 A sheet-like sealing material was produced in the same manner as in Example 1 except that (10) aluminum powder in Example 1 was not used.

Comparative Example 2 A sheet-like sealing material was produced in the same manner as in Example 3 except that (15) aluminum powder in Example 3 was not used.

The following five samples were evaluated as follows. Evaluation 1: Adhesion of coating film A sheet-shaped sealing material was cut into a rectangle having a width of 25 mm and a length of 50 mm, and was subjected to an automotive grade cationic electrodeposition coating (“E
-Coating U-600 Black (manufactured by Nippon Paint Co., Ltd.), and then placed in a constant temperature oven and heated at 160 ° C. for 30 minutes. The rectangular sheet was taken out of the oven, allowed to cool to room temperature, and then applied with an aminoalkyd paint obtained by crosslinking polyester with melamine using a bell spray. Such amino alkyd paints are called intermediate bake paints in the automotive industry. In this state, the rectangular sheet was placed in a constant temperature oven and heated at 140 ° C. for 30 minutes. At this time, the thickness of the coating film of the intermediate baking paint was 40 μm. Then, the rectangular sheet was taken out of the oven, allowed to cool naturally to room temperature, and a solid coating of an aminoalkyd type obtained by crosslinking polyester with melamine was applied on the intermediate baking paint. Such amino alkyd paints are referred to in the automotive industry as topcoat paints. In this state, the rectangular sheet is put again in a constant temperature oven,
Heated for 0 minutes. At this time, the thickness of the coating film of the top baking paint was 40 μm. Then, the sheet was taken out of the oven and allowed to cool to room temperature to complete a test substrate. Next, grid-shaped cuts were made at intervals of 2 mm using a razor in the coating portion of the test substrate. The cuts were made 11 times in each of the vertical and horizontal directions, and 100 lattices were formed. "Cellotape" (Nichiban) is attached so as to cover the entire lattice, and peeled off at a speed of 500 mm per minute at an angle of 180 ° with respect to the substrate, and some of the 100 lattices remain without peeling. Counted what you have.

Evaluation 2: Moisture Resistance A sheet-shaped sealing material was cut into a rectangle having a width of 25 mm and a length of 50 mm, and was attached to a steel plate coated with a vehicle undercoat paint as shown in Evaluation 1, and then placed in a constant temperature oven. And heated at 120 ° C. for 15 minutes. After removing the rectangular sheet from the oven and allowing it to cool to room temperature,
% In a constant temperature / humidity oven heated and humidified to a relative humidity of 72%, left for 72 hours, taken out of the oven, and allowed to cool down to room temperature. After application, the appearance of the rectangular sheet was visually evaluated.

Evaluation 3: Confirmation of Existence of Exposed Metal Powder on the Surface of Sealing Material The sheet-like sealing material was cut into a rectangle having a width of 25 mm and a length of 50 mm, and the undercoat paint for automobile as shown in Evaluation 1 was applied. After sticking to a steel plate, it was placed in a constant temperature oven and heated at 140 ° C. for 30 minutes. After removing the rectangular sheet from the oven and allowing it to cool naturally to room temperature, the rectangular sheet is cut into two for each steel plate using a diamond cutter, and the cross section is visually observed using a magnifying glass to check the exposure of the metal powder. The presence or absence was checked.

The results of the above evaluations 1 to 3 for Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0053]

[Table 1]

From the results shown in Table 1 above, all sheet-like sealing materials using the sealing material composition of the present invention have much higher coating film adhesion than conventional sealing materials containing no metal powder. You can see that. In Example 3, the coating film adhesion was inferior to that of Examples 1 and 2, but the coating film adhesion was inferior to that of Examples 1 and 2. It can be seen that the coating film adhesion was greatly improved. Further, in all of Examples 1 to 3, the metal powder was exposed on the surface of the sealing material, and due to the exposure of the metal powder, the surface energy of the sealing material was increased, and the adhesion to the coating film was improved. It is considered something. The moisture resistance is the same as that of the sealing material containing no metal powder, and it can be seen that the addition of the metal powder does not reduce the moisture resistance.

[0055]

The sealing material composition of the present invention and the sealing material obtained therefrom have improved adhesion to the coating film.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of one embodiment of the sealing material of the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the sealing material of the present invention, which includes metal powder only in the surface layer of the sealing material.

FIG. 3 is a cross-sectional view of still another embodiment of the sealing material of the present invention, which includes a barrier layer.

FIG. 4 is a cross-sectional view of one embodiment of a laminate including a steel sheet sealed with the sealing material of the present invention, a sealing material, and a coating film.

[Description of Signs] 1 ... Sealant 2 ... Low hygroscopic resin 3 ... Metal powder 4 ... Barrier layer 5 ... Laminate 6 ... Coating film 7 ... Steel plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08K 3/08 C08K 3/08 C08L 101/00 C08L 101/00 F term (Reference) 4F100 AA19 AB01B AB03A AK01B AK25 AR00C BA04 BA07 BA10A BA10D CC00D DC30A DE01B EJ54 GB32 JD02C JD15B JL11 YY00B 4H017 AA04 AA23 AA39 AB01 AB08 AB13 AC02 AC03 AC04 AD06 AE05 4J002 BG03W CD00X CF00X DA076 DA086 DA096 GJ02

Claims (9)

[Claims] 1. A sealing material composition comprising a low hygroscopic resin and metal powder. 2. The method according to claim 1, wherein the metal powder contains the low hygroscopic resin
The sealant composition according to claim 1, wherein the composition is contained in an amount of 30 to 150 parts by mass per part by mass. 3. The sealing material composition according to claim 1, wherein the average particle size of the metal powder is 100 μm or less. 4. The sealing material composition according to claim 1, for sealing a seam of a steel sheet. 5. A sealing material formed into a flat shape selected from the group consisting of a sheet, a tape and a strap, comprising the sealing material composition according to any one of claims 1 to 4. 6. The planar sealing material according to claim 5, wherein the metal powder is present only in the surface layer of the planar sealing material. 7. The method according to claim 5, further comprising a barrier layer.
A sealing material formed into a flat shape as described in the above. 8. The sealing material formed in a flat shape according to claim 5, for sealing a joint of a steel sheet. 9. A laminated structure comprising a steel sheet forming a seam, a sealing material formed into a flat shape according to claim 8, which seals the seam on the steel sheet, and a coating film on the sealing material. .