JP2002121351A - Thermosetting composition, and sealing article and sealing structure made by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting composition which gives a sealing article excellent in heat resistance and durability. SOLUTION: The thermosetting composition contains an epoxy-containing material, a curing agent for the epoxy-containing material, and a filler, wherein the epoxy-containing material contains an epoxidized thermoplastic resin having low moisture absorptivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermosetting composition,
The present invention relates to a sealing article and a sealing structure using the same.

[0002]

2. Description of the Related Art Vehicles such as automobiles and trucks have discontinuous joints formed by overlapping metal panels. Such discontinuous joints are usually sealed with a sealant. An example of a non-planar overlapping joint is a roof ditch. The roof ditch is formed in the front-rear direction of the vehicle by bending and overlapping side edges of a roof panel and side panels of the vehicle. The roof ditch has a U-shaped groove, and also has a function of collecting moisture and the like and discharging the same to the outside of the vehicle.

[0003] Sealants are supplied as liquid or solid materials depending on the requirements of the application. For example, in the automotive industry, fittings can be made of, for example, polyvinyl chloride (PVC).
Is usually sealed using a liquid plastisol consisting of
However, when the sealant is in a liquid state, there are portions where the construction is difficult. In some cases, it is necessary to use a sealing article having a certain shape, such as a sheet or tape.

Typical sealing articles are disclosed, for example, in JP-A-62-48787 and JP-A-2-272076 (US Pat. No. 5,088,088).
As disclosed in JP-A-505335, JP-A-2000-17248 and JP-A-2000-192013, it is constituted by a thermosetting composition that can be melted and flowed. Such a sealing article can be cured and sealed after flowing by heating to cover the discontinuity.

It is desirable that sealing articles of this type have poor water absorption. This is because when the sealing article having water absorbency is heated and cured after the coating step, it expands due to foaming of water and may cause delamination or float without adhering to the discontinuous portion. Such may allow the ingress of dust, moisture and other undesirable components. Further, even when a sealing article is provided with a coating film on the surface thereof in a vehicle coating process, similarly to a general sealant, it does not sufficiently adhere to the coating film or provides an unfavorable appearance to the coating film. There is also a risk of doing so.

The undesired appearance of the coating film is from -40 to
It may also be formed by stress generated at the interface between the coating and the sealing article having a different coefficient of thermal expansion at a low temperature such as -20 ° C. In particular, when the sealing article is applied to the groove of the roof ditch, the tendency is remarkable. The reason for this is that the coating film on such a sealing article tends to be relatively easily destroyed by not only the stress at the interface with the sealing article but also the constraint from the side wall of the groove. Furthermore, when the elasticity of the sealing article is relatively low at the low temperature described above, it is expected that the coating film is prevented from cracking due to a decrease in stress generated at the interface with the coating film.

[0007]

Accordingly, the present invention provides a thermosetting composition capable of adhering to a discontinuous portion with heat resistance and durability while maintaining the appearance of a coating film. It is an object to provide a sealing article and a sealing structure used.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has an epoxy-containing material,
A thermosetting composition, comprising: a curing agent for the epoxy-containing material; and a filler, wherein the epoxy-containing material includes a low-hygroscopic epoxidized thermoplastic resin.

[0009] In another aspect, the present invention is a sealing article characterized in that the thermosetting composition is formed into a sheet.

The present invention also provides, in yet another aspect,
A sealing structure comprising: an adherend having a discontinuous portion; and a thermosetting composition provided in the discontinuous portion and sealing the discontinuous portion, wherein the thermosetting composition is the present invention. Wherein the adhesive composition is a sealing structure.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail, but it will be readily apparent to those skilled in the art that the present invention is not limited thereto. As described above, the thermosetting composition according to the present invention includes a joint, a step, a joint, a joint, a crack, or another portion (hereinafter, these portions are collectively referred to as “discontinuous”) in a vehicle member. Section). FIG. 1 shows an example of a sealant structure formed by sealing a discontinuous portion using the thermosetting composition of the present invention.

In a sealing structure 10 shown in FIG. 1, two panels 1 and 2 are machined at right angles to form a U-shaped groove called a roof ditch (substrate) to form an adherend. It is produced by applying the thermosetting composition of the present invention to the joint A. Generally, roof ditch is found in vehicles such as automobiles and trucks. Such a roof ditch is usually formed in the front-rear direction of the vehicle by bending a side edge of the roof panel 1 of the vehicle and a side edge of the side panel 2 and welding them together. Such a roof ditch has a joint A as a discontinuity and is sealed by the coating of the thermosetting composition 3. As a result, the joints are prevented from being engulfed by moisture, dust and the like and other undesirable components. In the automobile industry, a coating film 5 is provided on the thermosetting composition 3 as needed.

As described above, the thermosetting composition of the present invention used as a sealant contains an epoxy-containing material, a curing agent for the epoxy-containing material, and a filler. Hereinafter, this component will be described in detail.

[0014] 1. Epoxy-Containing Material The epoxy-containing material used as the first component of the thermosetting composition of the present invention contains a low hygroscopic epoxidized thermoplastic resin, and further contains an epoxy resin and, if necessary, a compatibilizer.

(1) Low moisture absorption epoxidized thermoplastic resin Epoxidized thermoplastic resin is a thermoplastic resin having an epoxy group. Generally, a thermoplastic resin can impart a certain shape to a thermosetting composition. Further, the epoxidized thermoplastic resin contributes to the thermosetting reaction due to the presence of the epoxy group. As a result, when the thermosetting composition is cured, the cured product has heat resistance and durability.
In automotive roof sealers, this epoxy group allows the cured product to adhere to automotive paints (eg, organic solvent-based acrylic paints and organic solvent-based alkyd paints) and to automotive steel sheets coated with cationic electrodeposition. It will be easier. The adhesion of the cured product to the automotive paint is
It is advantageous for the painting process of automobiles. This is because when the vehicle body is painted, the cured product can be made the same color as the vehicle body. As a result, a cover material such as a mall is not required, and the appearance and appearance of the vehicle body are improved. In addition, the close contact with the steel plate also improves the durability and sealing performance of the sealer.

Further, in the thermosetting composition of the present invention, it is necessary that the epoxidized thermoplastic resin has as low hygroscopicity as possible, that is, low hygroscopicity. This is because such low hygroscopicity prevents the absorption of moisture into the thermosetting composition and, as a result, is advantageous in the automotive coating process as described in the section of the prior art. In addition, handling such as storage of the thermosetting composition is simplified. The term "low hygroscopicity" means that the epoxidized thermoplastic resin has a saturated water absorption of 0.2 wt% or less at 35 ° C. and a relative humidity of 80% RH. Such epoxidized thermoplastic resins typically have a solubility parameter (SP) of about 9 or less. As used herein, this solubility parameter is calculated using the small equation (PASmall, J. Appl. Chem.,
3, 71 (1953)).

Usually, such an epoxidized thermoplastic resin is used in an amount of 1,000, in consideration of flowability during molding and hot melting.
It has a molecular weight of 1010,000. The epoxidized thermoplastic resin generally has an epoxy equivalent of 200 to 15,000 in consideration of heat resistance, durability, coating film adhesion and water absorption.

A typical example of the above-mentioned epoxidized thermoplastic resin is an epoxidized ethylene-based thermoplastic resin.
This resin exhibits low hygroscopicity due to the presence of the ethylene moiety. As the epoxidized ethylene-based 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-2001-37028.
As disclosed in JP-A-0-316955 as one component of an adhesive and a hot melt composition, 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. In such a case,
The ethylene portion contributes to the low hygroscopicity of the thermosetting composition, and the glycidyl (meth) acrylate portion contributes to the adhesiveness of the automotive paint and the cation electrodeposited automotive steel sheet described later.

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 not 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.

Further, a typical ethylene-glycidyl (meth) acrylate copolymer is easily melted even at a relatively low temperature of about 120 ° C. or less, so that a thermosetting composition containing the same can be heated and fluidized for sealing. High fluidity is obtained, resulting in an appearance with high uniformity and smoothness. In addition, since it is possible to knead at a relatively low temperature in the heating and mixing process during the production of the sealer, there is little risk of causing a reaction between the thermosetting component and the curing agent during kneading, and further, a curing agent having higher reactivity is selected. You can also.

Unless the effects of the present invention are impaired, epoxidized thermoplastic resins include ethylene and glycidyl (meth)
A ternary ethylene-glycidyl (meth) acrylate copolymer obtained by copolymerizing or graft-polymerizing a third component other than acrylate may be used. Examples of such terpolymers are copolymers of alkyl (meth) acrylate and vinyl acetate, and examples of graft polymers are polystyrene, polyalkyl (meth) acrylate and acrylonitrile-styrene copolymer. It is obtained by grafting coalescence.

Another typical example of an epoxidized thermoplastic resin is an epoxidized styrene-based thermoplastic resin, which exhibits low hygroscopicity due to the presence of a conjugated diene. 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 epoxidized styrene-based 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 is added at about -30 ° C.
The durability (especially the vibration durability) at low temperatures up to this point can be enhanced. As a result, the epoxidized styrene-based thermoplastic resin is very advantageous for use in a sealer where a stress is repeatedly applied even at a low temperature, for example, a sealer for an automobile roof touch as described above. Also,
In automotive roof-titch sealer applications, the styrene and epoxy groups of the epoxidized styrene-based thermoplastic resin allow the cured product to be used in automotive paints (eg, organic solvent-based acrylic paints and organic solvent-based alkyd paints) and cationic electrodeposition. It comes into close contact with the painted automotive steel plate.

Examples of such an epoxidized styrene-based thermoplastic resin are a styrene-epoxidized butadiene-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.

It is preferable that the low moisture-absorbing epoxidized thermoplastic resin is contained in the thermosetting composition in an amount of 10 to 90% by weight. If the amount is less than about 10% by weight, the heat resistance and the low hygroscopicity decrease, and if the amount exceeds about 90% by weight, the filler relatively decreases and a low linear expansion coefficient may not be obtained.

(2) Epoxy resin Epoxy-containing materials include, in addition to the above-mentioned epoxidized thermoplastic resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, and glycidylamine type epoxy resin. A liquid or solid epoxy resin is included to further enhance the heat resistance and durability of the cured product of the thermosetting composition and the adhesion to the above-mentioned automotive paint. Desirable epoxy resin, for example, hydrogenated bisphenol A type epoxy resin, alicyclic epoxy resin, linear aliphatic epoxy resin such as butadiene skeleton epoxy resin, or glycidyl ester type epoxy resin such as dimer acid modified epoxy resin, Epoxy resin with relatively low polarity. This is because the epoxidized thermoplastic resin has excellent compatibility with the low water absorbing component, for example, the ethylene portion and the butadiene portion. Further, the absorption of moisture into the cured product is prevented, which is advantageous for the automobile coating process as described above. The amount of the epoxy resin is usually from 0 to 50 based on 100 parts by mass of the component (1), that is, 100 parts by mass of the low hygroscopic epoxidized thermoplastic resin.
0 parts by weight, preferably 5 to 400 parts by weight.

(3) Compatibilizer If necessary, the epoxy-containing material may further contain a compatibilizer. Specifically, this compatibilizer has a
0 to 300 parts by weight, preferably 1 to 100 parts by weight, based on 0 parts by weight of the low-hygroscopic epoxidized thermoplastic resin, the compatibility of the low-hygroscopic epoxidized thermoplastic resin with the epoxy resin. Can be increased. In the present invention, the compatibilizer is not particularly limited as long as the above-mentioned compatibility can be achieved, but preferably includes a polyester resin or an ethylene-vinyl acetate copolymer (EVA). In particular, when the polyester resin is blended with the low moisture-absorbing epoxidized thermoplastic resin in a predetermined ratio, not only the separation of the low moisture-absorbing epoxidized thermoplastic resin and the epoxy resin is prevented, but also the thermosetting resin is used. This is because the fluidity of the composition at the curing temperature (100 to 160 ° C.) can be greatly improved.

[0028] 2. The curing agent for the epoxy-containing material can cure the epoxy group contained in the epoxidized thermoplastic resin and the epoxy resin to provide a crosslinked structure in the thermosetting composition of the present invention, thereby obtaining a cured product. According to the present invention, the curing agent is not limited as long as a cured product can be obtained. Therefore, the curing agent, for example, amine compounds such as dicyandiamide, acryl compounds having a carboxyl group (including acid anhydride) in the molecule or rosin, imidazole derivatives, BF ₃ complexes, organic acid hydrazides, diaminomaleonitrile nitriles Alternatively, it may contain melamines or a mixture thereof. Further, the polarity of the curing agent is not limited. However, to cure the glycidyl group of the ethylene-glycidyl (meth) acrylate copolymer,
JP-A-9-137028 and JP-A-10-316
As disclosed in Japanese Patent No. 955, use of an acrylic compound containing a carboxyl group in a molecule or a curing agent containing rosin is required. Highly polar curing agent is ethylene-
Incompatible with glycidyl (meth) acrylate copolymer,
This is because such a curing agent is more compatible with the ethylene-glycidyl (meth) acrylate copolymer and hardens the glycidyl group of the ethylene-glycidyl (meth) acrylate copolymer, as compared with the case where the reaction cannot be substantially performed.

The curing agent may be used in combination with a curing accelerator. In particular, for the reaction between the curing agent having a carboxyl group and the epoxy, a curing accelerator containing a phenol-containing substance, an imidazole derivative or a tertiary amine can be advantageously used.

[0030] 3. Filler In the present invention, a filler containing , for example, calcium carbonate or silica or a mixture thereof is further added to the thermosetting composition. The filler can reduce the coefficient of linear expansion of the cured product. As a result, such a cured product was formed by applying the above-mentioned automotive paint thereon, in which the linear expansion coefficient was reduced, and the amount of shrinkage at a low temperature was reduced, especially at the above-mentioned temperature change at a low temperature. It becomes difficult to apply stress to the coating film. Thus, the formed coating film is hard to crack even at a low temperature.

When the filler is added as described above, generally, the thermosetting composition may be accompanied by undesired fluidity during heating and melting. Therefore, the thermosetting composition of the present invention preferably contains a plasticizer. By including a plasticizer, the thermosetting composition of the present invention maintains desired fluidity. This is because the plasticizer generally has a low viscosity and can contribute to improving the fluidity of the composition.

The plasticizer which may be contained in the thermosetting composition of the present invention includes, for example, phthalic esters such as di-2-ethylhexyl phthalate or diisononyl phthalate;
Adipic acid esters, epoxidized fatty acid esters,
Contains epoxidized soybean oil, epoxidized linseed oil, liquid terpene resin, liquid terpene phenol copolymer or liquid terpene styrene copolymer, azelaic esters, sebacic esters, epoxy hexaphthalic esters or mixtures thereof Plasticizer. Such a plasticizer can impart flexibility to a cured product of the thermosetting composition. Further, the cured product can lower the glass transition temperature and lower the elastic modulus even at a low temperature of −20 to −40 ° C. As a result, the cured product can greatly expand at such a low temperature, and dynamic durability such as vibration durability can be improved.

The above-mentioned thermosetting composition is used by molding into a sealing article having a predetermined shape such as a sheet, a tape, a rope or a strap. Specifically, the sealing article is placed on a discontinuity, such as a joint. The sealing article can then be made hot-melt-flowable by heating to seal the discontinuities. That is, when heated in a state where the discontinuous portion is covered, it softens and adapts to the surface of the discontinuous portion, thereby pushing out the trapped air. Thereafter, the sealing article cures upon heating (i.e., crosslinks by covalent bonds) and prevents flow upon subsequent cooling and reheating.

In the automotive industry, this discontinuity is found, for example, in the roof ditch, where the sealing article is applied. Such sealing articles are restrained not only on the bottom surface of the roof ditch but also on the side walls. Roof ditch, due to the bias and deflection of the panel that constitutes it,
The sealing article may be stressed from the side walls. However, due to the elasticity of the above-described thermosetting composition, the sealing article can flexibly follow even when subjected to a stress from the side wall at a relatively low temperature of about -30 ° C., and is not easily cracked.
As a result, intrusion of dust, moisture and other undesirable components can be prevented.

In the automobile industry, curing is performed in a heating step while a coating film is provided on the sealing article in the coating step after the sealing article of the roof ditch is melted and flowed by heating. This coating is constrained by the side walls of the roof ditch, as is the sealing article, and also constrained by the sealing article. As a result, interfacial stress generally occurs between the coating and the sealing article. Usually, this interfacial stress is often observed at low temperatures. At low temperatures, typical sealing articles are susceptible to shrinkage. This interfacial stress (P) is typically relaxed at temperatures above the glass transition temperature (Tg) of the sealing article,
At a temperature (T) below the glass transition temperature of the sealing article, it is represented by the following equation. P = ΔT · E · Δα where ΔT: T−Tg E: elastic modulus of the sealing article Δα: difference in linear expansion coefficient between the coating film and the sealing article.

In the case of the sealing article of the present invention, as described above, the elastic modulus is low and the difference in linear expansion coefficient is small. As a result, the sealing article of the present invention has a glass transition temperature (specifically, −30 to −10 ° C.) of −40 to −20 ° C. or less.
At such a low temperature, the stress is reduced and cracks in the coating film can be prevented.

Further, as described above, the sealing article of the present invention has a reduced moisture content before and after curing. As a result, even if the sealing article is left under high temperature and high pressure for several days before the coating process, even if the coating process is performed, the moisture expands due to foaming, so that the sealing component does not adhere to the discontinuous portion. Delamination or lifting can be prevented and the ingress of dust, moisture and other undesirable components can be avoided.
Also, such sealing components may adhere well to the coating or provide a pleasing appearance to the coating.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to these embodiments. For example,
The thermosetting composition of the present invention includes fine metal particles, inorganic particles,
A crystallization agent composed of a crystalline polymer or an organic pigment may be included. Such a crystallization agent can promote crystallization of the crystalline resin when the thermosetting composition contains a crystalline resin such as polyester, and as a result,
It is possible to prevent the performance of the thermosetting composition and the molded article as a sealing article from changing with time.

The thermosetting composition may further contain a modifier for improving the adhesion to a coating film provided thereon, as long as the effects of the present invention are not impaired. Such a modifier is a tackifier such as a terpene-based resin or an olefin copolymer obtained by copolymerizing a component having a relatively high polarity.

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 article. You may be. As described above, even when air bubbles enter the sealing article from the discontinuous surface of the sealing portion during heating and melting, the barrier layer can capture the air bubbles inside the sealing article. That is, it is possible to prevent bubbles from appearing on the surface of the sealing article, and to maintain and improve the preferable appearance of the coating film. Also, the barrier layer supports the sealing article,
The handleability can be improved. However, the barrier layer is not limited to the above. By irradiating the surface of the sealing article with radiation such as an electron beam, a crosslinked structure is provided on the surface,
A barrier layer may be formed.

Further, the present invention is not limited to the above-mentioned sealing article basically composed of a thermosetting composition in which each component is uniformly mixed. FIG. 2 is a side sectional view showing another embodiment of the sealing article of the present invention. The sealing article 20 is of a two-layer type, in which an upper layer 6 which may be provided with a coating film and a lower layer 7 which is in contact with an adherend having discontinuous portions.
And Each layer basically contains the epoxy-containing material and its curing agent uniformly, while the lower layer contains the uneven distribution of filler. When a plasticizer is used, the plasticizer is unevenly contained in the upper layer. In this case, the plasticizer and filler are separated from each other, effectively providing shrinkage of the sealing article itself and stress relief for the coating.

The present invention is not always applied only to simple sealing such as roof ditch. For example, in the case of a thermosetting composition having a specific composition described below,
For example, the present invention can be applied to a lower portion of a side sill below a door of a vehicle. More specifically, the lower portion of the side sill is provided behind the front wheel tires of the vehicle, and is susceptible to chipping impact such as pebbles and gravel on the road jumped up by the front tires while the vehicle is running. However, such impact can be reduced by applying a thermosetting composition having a specific composition to the side sill. This is because a thermosetting composition having this specific composition has a relatively soft rubber elasticity when cured. Therefore, there is no need to provide a cover member made of, for example, resin below the side sill to prevent noise and vibration due to the impact of chipping, and the vehicle can be reduced in weight.

When the thermosetting composition is formed into a specific shape such as a sealing article, it can be handled more easily than a PVC sol or a one-part urethane sealer that requires a coating robot. Thus, the use of PVC sols can be avoided.

Further, such a thermosetting composition has relatively poor fluidity even when heated. Therefore, even if this thermosetting composition is applied to the overhang surface below the side sill, it hardly drips from there. Therefore, no special measures are required for applying the overhang surface.

Further, the cured product of the thermosetting composition includes:
Coating with the above-mentioned steel plate paint is possible. as a result,
For example, by applying a paint of the same color as that of the vehicle body to the cured product, a favorable appearance can be easily given to the vehicle.

[0046]

EXAMPLES Next, the present invention will be described with reference to examples, but it goes without saying that the present invention is not limited to these examples. Example 1 Preparation of Thermosetting Composition / Production of Sealed Article First, the following components were used: (1) 30 parts by mass of an ethylene-glycidyl methacrylate copolymer containing 18% by mass of glycidyl methacrylate (trade name: CG5001, (2) 70 parts by mass of a thermoplastic polyester resin (compatibilizer, trade name: S320, manufactured by Huls) (3) 60 parts by weight of an epoxy resin having an epoxy equivalent of 190 (trade name: YD128, TOTO (4) 20 parts by mass of an epoxy resin having an epoxy equivalent of 600 to 700 (trade name: Epicoat 1002, manufactured by Yuka Shell); (5) 6 parts by mass of dicyandiamide (curing agent, trade name: H3636AS, (6) 4 parts by mass of an imidazole derivative (hardening accelerator, trade name 2MZA, manufactured by Shikoku Chemicals), (7) 50 parts by mass of calcium carbonate (filler, trade name Whiten SB,
(8) 2 parts by mass of a crystallization agent (trade name: Unilin425, manufactured by Toyo Petrolite) were charged into a twin-screw extruder having a shaft diameter of 30 mm and kneaded to prepare a thermosetting composition. . Thereafter, the thermosetting composition is extruded from a twin-screw extruder, and is applied onto one surface of a PET film substrate using a hot knife coater (comma coater type).
A sheet (sealing article) having a thickness of 0 mm was formed. The sheet is then cut to a length of 150 cm and a length of 3 cm.
(Hereinafter, also referred to as a “melt seal tape”), and prepared for the test and measurement described later.

Example 2 Ethylene-glycidyl methacrylate copolymer containing 18% by mass of glycidyl methacrylate (trade name: CG5001, manufactured by Sumitomo Chemical Co., Ltd.) (2) 20 parts by mass of the following components: (1) 70 parts by mass Epoxy resin having an epoxy equivalent of 200 (trade name PB3600, manufactured by Daicel Chemical Industries), (3)
6 parts by mass of a carboxyl group-containing rosin (curing agent, trade name KE604, manufactured by Arakawa Chemical) having an acid value of 240 mg KOH / g,
(4) 2.5 parts by mass of an imidazole derivative (curing accelerator,
(2MZA, Shikoku Chemicals), (5) 20 parts by mass of diisononyl phthalate (plasticizer), (6) 60 parts by mass of calcium carbonate (filler, brand name Whiten SB, made of Shiraishi calcium), and ( 7) A melt seal tape was formed in the same manner as in Example 1 using 10 parts by mass of a terpene-based resin (modifier, TO125, manufactured by Yashara Chemical).

Example 3 An epoxidized styrene / isoprene / styrene copolymer having an epoxy equivalent of 727 (trade name DSM105, manufactured by Daicel Chemical Industries, Ltd.) comprising 40 parts by weight of the following components:
(2) 30 parts by weight of a polyester resin (compatibilizer, trade name S1
402, manufactured by Huls) (3) 30 parts by weight of a polyester resin (compatibilizer, trade name: S320, manufactured by Huls) (4) 30 parts by weight of an epoxy resin having an epoxy equivalent of 190 (trade name)
YD-128, manufactured by Toto Kasei), (5) 3.3 parts by mass of dicyandiamide (hardener, trade name: H3636AS, manufactured by AC R), (6) 4.9 parts by mass, having an acid value of 240 mg KOH / g Carboxyl group-containing rosin (curing agent, trade name KE604, manufactured by Arakawa Chemical), (7) 4.9 parts by mass of imidazole derivative (curing accelerator, trade name 2MZA, manufactured by Shikoku Chemicals), (8) 10 parts by mass of calcium carbonate (Filler, trade name Whiteton SB, made of Shiroishi calcium), (9) 70 parts by mass of silica (filler, trade name FB-40S, made by Asahi Denka), (10) 15 parts by mass of phthalic acid di-
2-ethylhexyl (plasticizer, manufactured by Kyowa Hakko Kogyo), (11)
1.0 parts by mass of a crystallization agent (trade name: unilin425, manufactured by Toyo Petrolite Co., Ltd.); (12) 3.4 parts by mass of an antioxidant (trade name: Ir
ganox 1010 (manufactured by Ciba Geigy), and a melt seal tape was formed in the same manner as in Example 1.

Example 4 Preparation of thermosetting composition for chipping resistance, preparation of sheet The following components were used: (1) 25 parts by mass of an epoxidized styrene / isoprene / styrene copolymer having an epoxy equivalent of 5333 ( Product name: CT136, manufactured by Daicel Chemical Industries) (2)
75 parts by mass of polyester resin (Compatibilizer, trade name S1402
(3) 35 parts by weight of an epoxy resin having an epoxy equivalent of 200 (trade name: PB3600, manufactured by Daicel Chemical Industries); (4) 29 parts by weight of a carboxyl having an acid value of 240 mg KOH / g Group-containing rosin (curing agent, trade name KE604,
(Arakawa Chemical), (5) 2.9 parts by mass of imidazole derivative (curing accelerator, trade name 2M-OK, Shikoku Chemicals), (6) 34
Parts by weight of calcium carbonate (filler, brand name Whiten S
B, made of calcium shiraishi), (7) 15 parts by mass of diphthalic acid
2-ethylhexyl (plasticizer) and (8) 1.3 parts by mass of a crystallization agent (trade name: unilin425, manufactured by Toyo Petrolite Co., Ltd.)
Was charged into a twin-screw extruder having a shaft diameter of 15 mm and kneaded to prepare a thermosetting composition. Thereafter, the thermosetting composition is extruded from the twin-screw extruder, and a hot knife coater (comma coater type) is formed on one surface of the PET film substrate.
Was applied to form a 10 cm × 20 cm sheet (sealing article) having a thickness of 2.0 mm, which was prepared for a chipping resistance test described later.

Heat cycle test The sheets or tapes of Examples 1 to 3 were subjected to a heat cycle test as described below. First, a substrate for a heat cycle test was prepared as follows. First, an automotive-grade cationic electrodeposition coating with a depth of 25 mm and a thickness of 0.8 mm (Nippon Paint E-coating U-600 Black
) Is applied to a cold-rolled steel sheet (hereinafter, also referred to as a “cation electrodeposition coated sheet”) as shown in FIG.
An adherend 30 having a U-shaped groove having a depth of 5 mm and a width of 8 mm was prepared, and simulated the roof ditch described above.

The above-mentioned melt sealing tape was cut into rectangular test pieces having a length of 25 mm and a width of 7 mm. The specimen was then placed in a U-shaped groove and placed in a constant temperature oven at that temperature for 15 minutes at 110 ° C.
Heated for minutes. This simulates pre-drying of a sealing article in an automobile manufacturing line, and is called pre-cure.

Then, the adherend was taken out of the oven together with the test piece, allowed to cool to room temperature (25 ° C., the same applies hereinafter), and then applied to a vehicle body coating (ie, an aminoalkyd paint obtained by crosslinking polyester with melamine). Were sprayed onto them, and the adherend was again placed in an oven together with the test pieces and heated at a temperature of 140 ° C. for 18 minutes. The above-mentioned paints are called intermediate baking paints in the automotive industry. At this time, the thickness of the intermediate baking paint was 35
μm.

Then, the adherend with the test piece was taken out of the constant temperature oven and allowed to cool to room temperature, and then a solid coating of aminoalkyd type obtained by crosslinking polyester with melamine was applied on the intermediate baking paint. Such aminoalkyd-type solid paints are called top-coat baking paints in the automotive industry. In this state, the adherend with the test piece was put again in a constant temperature oven and left at a temperature of 140 ° C. for 18 minutes. At this time, the thickness of the coating film of the top baking paint was 40 μm. Then, remove the sheet from the constant temperature oven and let it cool to room temperature to make a test board,
It prepared for the heat cycle test mentioned later.

Thereafter, the test substrate described above was put into a cycle tester, and heat was applied according to the following cycle. Room temperature → 4 hours at 90 ° C → 1.5 hours at -40 ° C → 70 ° C, 95% RH
3 hours → 1.5 hours at −40 ° C. → room temperature After repeating this cycle 10 times, the test substrate was taken out of the cycle tester, and the appearance of the coating film on the test piece was visually inspected. In each case, no crack was observed in the coating film.

Low temperature elongation measurement and water absorption measurement The melt absorption tape was measured for the melt seal tape of Example 1.
And about the melt seal tape of Example 2, low temperature elongation measurement and water absorption measurement were performed as shown below.

Water Absorption Measurement The above-mentioned melt seal tape (uncured) was cut and cut.
After being formed into a rectangle of 40 mm × 50 mm, it was placed in an oven and left at a temperature of 35 ° C. and a relative humidity of 85% RH for 3 days. Then, the melt seal tape was taken out of the oven and the water content was measured by the Karl Fischer method. The water content was 0.36 wt% in Example 1 and 0.29 wt% in Example 2. Do you get it.

After measuring the low-temperature elongation of the melt seal tape at 110 ° C. for 15 minutes, it was further heated at 140 ° C. for 45 minutes to obtain a cured product. Then, this cured product was punched with a dumbbell No. 1 to make a sample. This sample was pulled at a pulling rate of 50 mm / min at a temperature of −20 ° C., and its elongation was measured. As a result, the elongation was found to be 88%.

Coating Film Adhesion Test and Hygroscopic Foaming Test The sheet or tape of Example 3 was subjected to the following coating film adhesion test and hygroscopic foaming test. Coating film adhesion test In this test, a substrate similar to the test substrate used in the above-described thermal cycle test was prepared. First, the sheet of Example 3 was cut into a rectangular sample of 25 mm × 50 mm. Then, this sample was stuck on the above-mentioned cationic electrodeposition coated plate, and in this state, it was preheated at a temperature of 110 ° C. for 15 minutes. Then, after applying an intermediate paint for automobiles to this sample, the sample was heated at a temperature of 140 ° C. for 18 minutes. Then, after further coating the automotive topcoat with the automotive topcoat, the test substrate was prepared by heating at 140 ° C. for 18 minutes.

Next, a so-called grid test was carried out using this test substrate according to JIS K5400 of Japanese Industrial Standard. That is, the coating film and the adhesive composition were cut with a razor to form 25 squares of 2 mm × 2 mm. Then, Nichiban Cellotape (trademark) was applied to the surface of the coating film and then peeled off at a stretch, but no peeling of the coating film was observed. This grid test was also performed after the test substrate was immersed in warm water at 40 ° C. for 2 weeks, but no peeling of the coating film was observed.

[0060] hygroscopicity foaming test In this test, firstly, one reference test substrates, and were prepared two comparative test substrate in consideration of moisture absorption envisaged in automobile production lines as follows. The reference test board was cut from the sheet of Example 3 and applied to an adherend having a U-shaped groove having a depth of 10 mm and a width of 15 mm using a rectangular test piece of 7 mm x 25 mm. Other than that, it is the same as the test substrate of the thermal cycle test.

The first comparative test substrate was left at 35 ° C. and 80% RH for 3 days before being heated at 110 ° C. for 15 minutes after being attached to the above-mentioned cationic electrodeposition coated plate. Except for this, it is the same as the above-mentioned reference test substrate. Also,
The second comparative test substrate was heated at a temperature of 110 ° C. for 15 minutes, and then heated to a temperature of 35 ° C. before applying an intermediate coating for automobiles.
Same as the above-mentioned reference test substrate except that the substrate was left under a relative humidity of 80% RH for 3 days.

When the reference test board and the first comparative test board and the second comparative test board were visually inspected, the appearance between the reference test board and the first comparative test board and the second comparative test board was apparent. No difference was found. Similarly, no difference in appearance was observed between the first comparative test substrate and the second comparative test substrate in any of the examples.

Chipping Resistance Test The sheet of Example 4 was cut to obtain a rectangular sample of 50 mm × 100 mm. This sample was attached to a 75 mm × 150 mm cationic electrodeposition coated plate, and preheated at 110 ° C. for 10 minutes in this state. After the application of the intermediate coating for automobiles, the coating was heated at 140 ° C. for 18 minutes. Furthermore, after applying the automotive topcoat on the automotive intermediate paint, 14
A test substrate was prepared by heating at 0 ° C. for 18 minutes.

Next, a chipping resistance test was performed using this test substrate. That is, 30 granite granite
Collisions were made vertically from a distance of cm. At this time, the crushed stone was discharged at an air pressure of 0.4 MPa and an air flow rate of 40 L / sec. The test was conducted at two temperatures of 25 ° C and -20 ° C. In each case, no cracks were found in the steel sheet and no defects were found in the test piece, and only a crack was formed in the coating film on the test piece surface. Was.

[0065]

As described above, according to the present invention,
While maintaining the appearance of the coating film provided on it, heat resistance,
It is possible to provide a thermosetting composition that provides a sealing with excellent durability.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a preferred embodiment of a sealing structure according to the present invention.

FIG. 2 is a side sectional view showing a preferred embodiment of a sealing article according to the present invention.

FIG. 3 is a perspective view of a substrate used for a heat cycle test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Roof panel 2 ... Side panel 3 ... Thermosetting composition (sealing article)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 63/08 C08L 63/08 C09K 3/10 C09K 3/10 L (72) Inventor Tomohiro Koiwa Sagamihara, Kanagawa (8) Inventor Kotaro Shinozaki 3-8-8 Minamihashimoto, Sagamihara City, Kanagawa Prefecture Sumitomo 3M Co., Ltd. F term (reference) 4F071 AA42 AE04 AE17 AF10 AH07 AH19 BB02 BC01 4H017 AA04 AB08 AC03 AD06 AE05 4J002 CD021 CD051 CD061 CD081 CD131 CD162 CD181 CD191 DE236 DJ016 EH097 EH147 FD016 FD022 FD027 GJ00 4J036 AA01 AK02 AK03 AK04 AK11 AK19 DA01 DB15 DC02 DC31 DC35 DC41 FA03 FA05 FB03 JA03 FB03

Claims (7)

[Claims] 1. A thermosetting composition comprising: an epoxy-containing material; a curing agent for the epoxy-containing material; and a filler, wherein the epoxy-containing material comprises a low hygroscopic epoxidized thermoplastic resin. . 2. The thermosetting composition according to claim 1, further comprising a plasticizer. 3. The epoxidized thermoplastic resin having a low hygroscopicity is at least one selected from the group consisting of an epoxidized ethylene-based thermoplastic resin and an epoxidized styrene-based thermoplastic resin. Item 1 or 2
3. The thermosetting composition according to item 1. 4. The thermosetting composition according to claim 3, wherein the epoxidized ethylene-based thermoplastic resin is an ethylene-glycidyl (meth) acrylate copolymer. 5. The thermosetting composition according to claim 3, wherein the epoxidized styrene-based thermoplastic resin is a styrene-epoxidized butadiene-styrene copolymer or a styrene-epoxidized isoprene-styrene copolymer. 6. A sealing article, wherein the thermosetting composition according to claim 1 is formed into a sheet. 7. An adherend having a discontinuous portion, and the thermosetting composition according to claim 1, which is provided in the discontinuous portion and seals the discontinuous portion. A sealing structure comprising: