JPH10101902A - Epoxy resin composition for reinforcing vehicle body and method of reinforcing vehicle body - Google Patents

Abstract

[PROBLEMS] To reinforce a box-shaped closed-section member of a vehicle with a small increase in weight. SOLUTION: An epoxy resin composition having impact resistance is provided by introducing an epoxy group into an acrylate or methacrylate copolymer resin particle,
This is applied to a pre-formed steel plate and pseudo-hardened by heat treatment to prevent dripping. After assembling a box-shaped member using this steel plate, the car body is foamed and filled in the baking process at the time of car body electrodeposition coating Provide reinforcement method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel epoxy resin composition for reinforcing a vehicle body, and more particularly, to a composition comprising an epoxy group-containing modifier for imparting toughness and pseudo-curability. Prevents dripping by coating and pseudo-curing on a preformed steel sheet, assembling a box-shaped member using the steel sheet, and then baking, filling, or heating in the baking process at the time of body electrodeposition coating After being pseudo-hardened by sheeting and trimming into a vehicle body shape, it is bonded to a preformed steel plate via a stopper such as an adhesive or clip to prevent falling off and outflow, and a box shape using the steel plate The present invention relates to an epoxy resin-based composition for reinforcing a vehicle body and a method for reinforcing a vehicle body, characterized in that, after assembling the members, foaming and filling are performed in a baking step at the time of electrodeposition coating of the vehicle body to improve the rigidity of the vehicle body.

[0002]

2. Description of the Related Art In general, in a vehicle body structure, a skeleton of each part of the vehicle body is firmly formed in terms of running stability, riding comfort, noise, and vibration performance. The conventional body skeleton has a box-shaped closed cross-section structure and is manufactured in various cross-sectional shapes.However, in order to reduce the weight of the vehicle body due to social demands for fuel efficiency improvement from the viewpoint of depletion of fossil fuel and atmospheric environment, Each of them has a thin plate structure, and generally uses a metal reinforcing material to compensate for the decrease in strength. On the other hand, Japanese Patent Laid-Open No. 48-2631 proposes a vehicle body structure in which a rigid urethane foam is filled in the inside of the closed section to reinforce the vehicle body skeleton. Filling with foam is highly effective in suppressing wall buckling and significantly improving the strength of the box-shaped member.Therefore, compared to a method of reinforcing a vehicle body with a metal reinforcing material, without significantly increasing the vehicle body weight,
The rigidity can be improved. In addition to the urethane-based resin, the olefin-based resin foam filler (Nippon Sika Co., Ltd.
0) and epoxy resin foam filler (manufactured by Iida Sangyo, OR
OTEX 815), etc., all of which are foamed / filled types in a vehicle body painting process.

[0003]

However, in the reinforcing method using a urethane resin, urethane from a small hole of the box-shaped member and a joint of the box-shaped closed-section member at the time of injection / foaming of the urethane stock solution into the box-shaped closed-section member during construction. Since leakage of the undiluted solution occurs to a considerable extent, it is necessary to take measures to prevent this, and it is considered that application to a production line of an automobile is difficult. Also, from the viewpoint of improving the working environment,
In recent years, the foaming method using CFCs has been replaced by a foaming method using water. However, the water foaming method has a problem that it is difficult to achieve uniform foaming compared to the CFC foaming method. Further, in the case of the olefin resin foam, since low molecular weight polyethylene wax or the like is used as the base olefin resin, the rigidity / strength of the material is not sufficient. / The effect of improving rigidity is not sufficient. On the other hand, in the case of the epoxy resin-based foam material, first, it is necessary to compensate for the disadvantage that the impact resistance of the epoxy resin is insufficient. The input of the load to the vehicle body is not necessarily static, and the impact load may be applied to the vehicle body due to unevenness of the road surface during running.
Impact resistance and toughness that can withstand such an impact load are required. Methods of improving the impact resistance are roughly classified into a method of improving the chemical structure itself of the epoxy resin and a method of adding a separately prepared impact modifier to the epoxy resin. An epoxy resin that can sufficiently satisfy impact properties cannot be obtained. On the other hand, in the latter method,
(1) a method of adding a soluble elastomer monomer to an uncured epoxy resin and simultaneously polymerizing the two, (2) a method of adding a compatible elastomeric polymer, and (3) a fine particle-like weight for improving impact resistance. Methods for dispersing the coalescence are known. For (1), the interpenetrating network structure: IPN (I
Although this method is known as an “inter-penetrating network”, it generally has disadvantages such as a decrease in the softening point of the product and a variation in mechanical strength. Also,
Regarding the method (2), various examples of modifying the rubber by adding an elastomer component such as a butadiene-acrylonitrile copolymer rubber (CTBN or ATBN) having a carboxyl group or an amino group at a terminal have been proposed, and some of them are practically used. However, those obtained by this method cannot be said to be sufficiently satisfactory in terms of impact resistance and toughness for use in reinforcing the rigidity of a vehicle body. Further, in the method (3), many impact modifiers such as polyamide resins have been proposed, but all of them have a drawback that their pseudo-effects are insufficient. The pseudo-effect herein refers to a property in which a liquid and a paste-like epoxy resin composition solidifies to a non-adhesive or adhesive state at a lower temperature than the thermosetting, and has the following advantages. I have. That is, in the conventional foam filler, when arranging the uncured material on the vehicle body steel plate, it is necessary to use a dedicated clip or an adhesive material. There is a possibility of causing problems such as falling off due to defective setting or adhesive. On the other hand, after applying to the steel plate, heating is performed in a short period of time to form a pseudo-cured product, whereby it is possible to prevent falling off and contamination of the pretreatment liquid.

In general, it is known that when a rubber component having a glass transition temperature of -30 ° C. or less is added as a plastic impact resistance improver, it acts to relieve external stress, thereby greatly improving the impact resistance. However, most of such rubber components, when a liquid epoxy is used as a base material, the dispersibility thereof is easily affected by the mixing state, and the obtained composition has an unstable storage property, It is not practical for automotive production applications that require stability.

If the viscosity of the resin sharply decreases in the foaming temperature range, it is difficult to retain the gas generated from the foaming agent in the resin, and it is difficult to break the foam to form a foam. . In order for foam cells to be stably present in the foam, the temperature dependence of the resin viscosity in the foaming temperature range must be controlled. For this purpose, it is necessary to add an elastomer or the like having high compatibility with the epoxy resin to control the temperature dependence of the viscosity, or to control the temperature dependence of the viscosity by physical crosslinking. However, the method of controlling the viscosity by adding an elastomer has the disadvantage that the rigidity inherent in the epoxy composition is reduced, and when controlling the viscosity by cross-linking involving a chemical reaction, the cross-link density depends on the reaction conditions. However, since it cannot be strictly controlled, the viscosity is too high and the foaming becomes insufficient, and there is a possibility that the box-shaped member of the automobile is not sufficiently filled.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by introducing an epoxy group into acrylate or methacrylate copolymer resin particles, the impact resistance was improved. An epoxy resin composition provided, applied to a pre-formed steel sheet, pseudo-hardened by heat treatment to prevent dripping, and after assembling a box-shaped member using the steel sheet, baking at the time of electrodeposition coating of a car body In the process, after foaming, filling or pseudo-curing by heating and sheeting and trimming to the body shape,
It adheres to a preformed steel plate via a stopper such as an adhesive or a clip to prevent it from falling off and flowing out. After assembling a box-shaped member using the steel plate, foaming occurs during the baking process during body electrodeposition coating The present inventors have found that the body can be reinforced by filling the body with light weight, and the present invention has been achieved. In particular,
(A) 100 parts by weight of an epoxy resin derived from bisphenol A and / or bisphenol F,
(B) 10 to 100 parts by weight of a powdery acrylate or methacrylate polymer having an average particle size of 1 to 100 μ or less,
(C) 3 to 30 parts by weight of a thermally activated curing agent for epoxy resin,
An epoxy resin-based composition for reinforcing a vehicle body, comprising (D) 0.5 to 15 parts by weight of a thermally decomposable organic foaming agent and (E) 3 to 150 parts by weight of an inorganic filler. More specifically, an epoxy resin composition for reinforcing a vehicle body, wherein the acrylate or methacrylate polymer is a resin powder particle containing 0.2% by weight or more of an epoxy group. And applying the composition to a pre-formed steel sheet, pseudo-hardening by heat treatment to prevent dripping, and after assembling a box-shaped member using the steel sheet, in a baking step at the time of body electrodeposition coating, foaming, After filling or pseudo-hardening by heating to make a sheet and trimming it into a vehicle body shape, it is adhered to a preformed steel plate via a hook such as an adhesive or a clip to prevent falling off and outflow. An object of the present invention is to provide a method of reinforcing a vehicle body capable of reinforcing a vehicle body skeleton lightly by foaming and filling in a baking process at the time of electrodeposition coating of a vehicle body after assembling a box-shaped member using a steel plate.

[0007]

Hereinafter, embodiments of the present invention will be described in detail. Examples of the epoxy resin derived from bisphenol A used as the component (A) in the composition of the present invention include those represented by the following chemical formula 1. Examples of the epoxy resin derived from bisphenol F include those represented by the following chemical formula 2.

Embedded image

In the chemical formulas 1 and 2, n is 0.
Among the above numbers, those having an average value of less than 1 are preferable because they are liquid at room temperature. In addition to being able to mix and use the resins of Formula 1 and Formula 2,
Alternatively, a bisphenol A unit and a bisphenol F unit in a mixed chain can also be suitably used as the bisphenol chain portion of the chemical formula 2.

The epoxy group-containing acrylate or methacrylate resin particles used as the component (B) in the composition of the present invention are obtained by converting an epoxy group-containing monomer or polymer into a (meth) acrylate monomer or polymer. However, it can be obtained by known methods such as copolymerization, graft polymerization, mixing and post-treatment. Examples of the epoxy group-containing monomer or polymer for introducing an epoxy group include allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, glycidyl-P-vinyl benzoate, methyl glycidyl itaconate, glycidyl ethyl malate, and glycidyl vinyl sulfonic acid. Or glycidyl esters of unsaturated acids such as glycidyl (meth) allyl sulfonate, and monomers such as epoxy olefins such as butadiene monooxide, vinylcyclohexene monooxide, and 2-methyl-5,6-epoxyhexene, or polymerization thereof. These may be used alone or in combination of two or more. Examples of the monomers constituting the (meth) acrylate polymer include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate and stearyl methacrylate, alkyl acrylates such as methyl acrylate and butyl acrylate, and alkyls such as butoxyethyl (meth) acrylate. Glycol (meth) acrylate, alkylene glycol mono (meth) acrylate and the like can be mentioned, and these may be used alone or in combination of two or more.

The resin particles thus obtained preferably contain at least 0.2% by weight of epoxy groups. The epoxy group content of this monomer unit is 0.2% by weight
If it is less than 3, the interfacial bonding and adhesion of the (meth) acrylate resin to the epoxy resin three-dimensional crosslinked structure become weak, and it is not possible to improve rigidity or obtain sufficient impact strength. Further, the polymer needs to have a fine particle size, and preferably has an average particle size in the range of 1 to 100 μm. When the average particle diameter is smaller than 1 μm, the dispersion in the epoxy resin is deteriorated due to the adsorption force between the particles, which hinders production and mixing. When the average particle size is larger than 100 μm, when the composition is formed, pseudo-curability is inferior and impact resistance is lowered.

Examples of the heat-active curing agent for the epoxy resin used as the component (C) in the composition of the present invention include dicyandiamide, 4,4'-diaminodiphenylsulfone, and 2-n-heptadecylimidazole. Imidazole derivatives, isophthalic dihydrazide,
N, N-dialkylurea derivatives, N, N-dialkylthiourea derivatives, acid anhydrides such as tetrahydrophthalic anhydride, isophoronediamine, m-phenylenediamine,
N-aminoethylpiperazine, melamine, guanamine,
Boron trifluoride complex compounds, trisdimethylaminomethylphenol and the like, which may be used alone or in combination of two or more, among which dicyandiamide is particularly preferred is there. in this case,
To achieve sufficient foaming, the baking temperature of
The temperature is preferably in the range of 0 to 210 ° C., and the baking time is preferably in the range of 10 to 30 minutes. The amount of the heat-active curing agent (C) is not particularly limited, but is usually 3 to 30 parts by weight based on 100 parts by weight of the epoxy resin (A). If the amount is less than 3 parts by weight, it will not be sufficiently cured and the rigidity / strength will be remarkably reduced. If it exceeds 30 parts by weight, an excessive exothermic reaction will take place during curing, causing partial decomposition and thermal deterioration, It causes the mechanical strength of the composition to be significantly impaired.

Examples of the organic blowing agent used as the component (D) in the composition of the present invention include azo compounds such as azodicarbonamide and azobisisobutyronitrile, and nitroso compounds such as dinitrosopentamethylenetetramine. , P-toluenesulfonyl hydrazide,
Examples thereof include sulfohydrazide compounds such as 4,4'-oxybenzenesulfonylhydrazide. These may be used alone or in combination of two or more. Among them, azodicarboxylic acid is particularly preferred. Amides are preferred. In addition, when using an organic thermal decomposition type foaming agent, usually zinc white, zinc nitrate, lead phthalate, lead carbonate, tribasic lead phosphate, Inorganic salts such as tribasic lead sulfate, zinc fatty acid soap, lead fatty acid soap, metal soap such as cadmium fatty acid soap, boric acid, oxalic acid, succinic acid, acids such as adipic acid, urea, biurea, ethanolamine, glycol,
One or more of glycerin and the like can be mixed and used. The blending amount of the organic foaming agent of the component (D) is not particularly limited, but is usually preferably in the range of 0.5 to 15 parts by weight based on 100 parts by weight of the epoxy resin of the component (A). is there. If the amount is less than 0.5 part by weight, the foaming becomes insufficient, and if it exceeds 15 parts by weight, the control of the foaming is not effective, and stable mechanical properties cannot be obtained.

The inorganic filler used as the component (E) in the composition of the present invention includes, for example, calcium carbonate, talc, clay, mica, aluminum hydroxide,
Glass beads, shirasu balloons and the like may be mentioned, and these may be used alone or in combination of two or more. Among them, calcium carbonate is particularly preferable. The amount of the inorganic filler used as the component (E) is not particularly limited, but is usually 3 to 150 parts by weight based on 100 parts by weight of the epoxy resin (A). If the amount is less than 3 parts by weight, a sufficient reinforcing effect cannot be obtained. If the amount exceeds 150 parts by weight, the viscosity increases remarkably, making application and adhesion difficult. It may cause damage.

The epoxy resin composition of the present invention comprises an epoxy resin as component (A), acrylate or methacrylate resin powder particles as component (B), and a thermally activated curing agent as component (C). It can be adjusted by blending the agent, the inorganic filler of the component (E), and the additional components used as desired, and mixing them uniformly. Examples of the additive component to be added to the composition include a plasticizer, a diluent, a stabilizer, an emulsifier, a reinforcing agent, a coloring agent, an antioxidant, an ultraviolet absorber, a lubricant, a thixotropy-imparting agent, and a curing accelerator. No.

[0015]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following. still,
The physical properties of the composition were evaluated by the following methods. (1) Pseudo-hardening A cold-rolled steel sheet is coated with a coating gun using a coating gun.
After pseudo-curing with hot air at 20 ° C. for 20 seconds, the epoxy resin composition was left in a hot-air drying oven at 160 ° C. for 20 minutes to foam the epoxy resin composition and evaluated according to the following criteria.

○ The gelled composition does not fall off and is sufficiently foamed. △ The gelled composition falls off or has insufficient foaming. × Does not gelate. (2) Tensile shear strength The adhesive strength was baked on an untreated cold-rolled steel sheet in the same manner as above and evaluated according to JIS K6850.

(3) Impact test A 700-mm long U-shaped cold-rolled steel sheet press-formed in advance to have a cross-sectional dimension of 50 mm x 50 mm was inserted into a steel sheet having a length of 7 mm.
Application was performed using an application gun over 00 mm.
Pseudo-curing with hot air at 0 ° C for 20 seconds. A closing plate is integrated with this U-shaped steel plate member by spot welding to form a box-shaped cross-section member, which is left in a hot-air drying oven at a temperature of 160 ° C for 20 minutes to foam and fill the epoxy resin composition. Let it.

Using the box-shaped cross-section member assembled as described above, a hemispherical dropper having a weight of 5 kgf was applied to a 7 m / sec. The foam was collided at a speed and the presence or absence of breakage of the foam was evaluated according to the following criteria. ○ The foam is not broken. △ The foam is partially broken. × The foam is broken. (4) Member rigidity. Use the same box-shaped cross-section as used in (3). Figure 1
The epoxy resin composition was compared with an unfilled box-shaped section member, and the rigidity was evaluated according to the following criteria. ○ The rigidity was sufficiently improved to a satisfactory level. △ The rigidity was improved but not at a satisfactory level. × The rigidity was not improved. (Example 1) 5 parts of glycidyl methacrylate and 95 parts of methyl methacrylate The part was emulsion-polymerized and atomized by spray drying to obtain reinforcing resin particles having an average particle size of 3 μm and an epoxy group content of 2.6% by weight. With respect to 30 parts by weight of the thus obtained reinforcing resin particles, FIG.
As shown in FIGS. 5 and 6, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of a curing agent dicyandiamide, 16 parts by weight of an organic blowing agent azodicarbonamide,
Then, 6 parts by weight of an inorganic filler and calcium carbonate were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. This composition was previously prepared with a cross-sectional dimension of 5
Length 7 press-formed to be 0mm x 50mm
Coating is applied to a 00 mm U-shaped cold-rolled steel sheet using a coating gun over a length of 700 mm, and pseudo-hardened with hot air at 110 ° C. for 20 seconds. A closing plate was integrated with this U-shaped steel plate member by spot welding to form a box-shaped cross-section member, which was placed in a hot-air drying oven at a temperature of 160 ° C. for 20 minutes.
The epoxy resin composition is foamed and filled by being left for minutes. Using the box-shaped cross-section member assembled in this way,
The evaluation results are shown in FIGS. (Example 2) In Example 2, the compounding amount of the methacrylate resin particles was changed to 180 parts by weight based on 200 parts by weight of the bisphenol A type epoxy resin.
Everything else is the same as in the first embodiment.

Comparative Examples 1 and 2 In Comparative Example 1, the methacrylate resin was blended so as to be 15 parts by weight based on 200 parts by weight of the bisphenol A type epoxy resin. In Comparative Example 2, the mixing was performed so that the methacrylate resin was 220 parts by weight with respect to 200 parts by weight of the bisphenol A type epoxy resin. All other aspects are the same as in the first embodiment.

(Examples 3 and 4) In Example 3, methyl methacrylate 9 was added to 5 parts of glycidyl methacrylate.
Emulsion polymerization of 5 parts, this is atomized by spray drying,
Reinforcement resin particles having an average particle size of 3 μm and an epoxy group content of 2.6% by weight were obtained. In Example 4, 95 parts of methyl methacrylate was subjected to suspension polymerization with respect to 5 parts of glycidyl methacrylate to obtain reinforcing resin particles having an average particle diameter of 80 μm. Liquid bisphenol A type, epoxy resin 200 parts by weight, curing agent dicyandiamide 16 parts by weight, organic blowing agent azodicarbonamide 16 parts by weight, and inorganic based The filler and 60 parts by weight of calcium carbonate were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

Comparative Examples 3 and 4 In Comparative Example 3, methyl methacrylate 9 was added to glycidyl methacrylate 5 parts.
Emulsion polymerization of 5 parts, this is atomized by spray drying,
In Comparative Example 4, 95 parts of methyl methacrylate was suspension-polymerized with 5 parts of glycidyl methacrylate to form a reinforcement having an average particle diameter of 120 μm. Agent resin particles were obtained. Others are all the same as the third and fourth embodiments. (Examples 5 and 6) 95 parts of methyl methacrylate was emulsion-polymerized with respect to 5 parts of glycidyl methacrylate, and this was atomized by spray drying to obtain a reinforcing resin having an average particle diameter of 3 μm and an epoxy group content of 2.6% by weight. Particles were obtained. With respect to a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, and 60 parts by weight of an inorganic filler calcium carbonate. Then, 10 parts by weight of the curing agent dicyandiamide in Example 5 and 50 parts by weight in Example 6 were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Comparative Examples 5 and 6)
In Comparative Example 5, the compounding amount of the curing agent dicyandiamide to 200 parts by weight of the liquid bisphenol A type epoxy resin was 4
All parts are the same as in Examples 5 and 6, except that in Comparative Example 6, 70 parts by weight were used.

(Examples 7 and 8) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to give an average particle diameter of 3 μm.
m, and a reinforcing resin particle having an epoxy group content of 2.6% by weight was obtained. A mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of a curing agent dicyandiamide, and 60 parts by weight of an inorganic filler calcium carbonate was mixed with an organic resin. 2 parts by weight of the blowing agent azodicarbonamide in Example 7 and 30 parts by weight in Example 8 were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Comparative Examples 7 and 8)
The same as Examples 7 and 8, except that the compounding amount of the organic blowing agent azodicarbonamide to 200 parts by weight of the liquid bisphenol A type epoxy resin was 0.2 parts by weight in Comparative Example 7 and 40 parts by weight in Comparative Example 8. It is.

(Examples 9 and 10) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to give an average particle diameter of 3 μm.
m, and a reinforcing resin particle having an epoxy group content of 2.6% by weight was obtained. The mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, and 16 parts by weight of a curing agent dicyandiamide was mixed with an inorganic resin. In Example 9, the filler calcium carbonate was used in an amount of 10 parts by weight,
In Example 10, 300 parts by weight were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Comparative Examples 9 and 10) Compared with Examples 9 and 10, the amount of the inorganic filler calcium carbonate was set to 2 parts by weight with respect to 200 parts by weight of the liquid bisphenol A type epoxy resin. Are all the same as Examples 9 and 10, except that 400 parts by weight were used.

Example 11 1000 parts of methyl methacrylate was emulsion-polymerized with respect to 4 parts of glycidyl methacrylate, and this was atomized by spray drying to give an average particle diameter of 3 μm.
m, a reinforcing agent tree particle having an epoxy group content of 0.2% by weight was obtained. The thus obtained reinforcing resin particles 60 parts by weight, liquid bisphenol A type epoxy resin 200 parts by weight, organic blowing agent azodicarbonamide 16 parts by weight, curing agent dicyandiamide 16 parts by weight, inorganic filler calcium carbonate 60 parts by weight were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Comparative Example 11) 1000 parts of methyl methacrylate was emulsion-polymerized with respect to 2 parts of glycidyl methacrylate, and this was atomized by spray drying to obtain an average particle diameter of 3 μm.
m, and a reinforcing resin particle having an epoxy group content of 0.1% by weight was obtained. All others are the same as in the eleventh embodiment.

(Examples 12 and 13) 95 parts of methyl methacrylate was emulsion-polymerized to 5 parts of glycidyl methacrylate, and this was atomized by spray drying to obtain an average particle diameter of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. For a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, and 16 parts by weight of a curing agent dicyandiamide, In Example 12, 60 parts by weight of talc as an inorganic filler, and in Example 13, 60 parts by weight of silica were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Example 14) Glycidyl acrylate 5
Emulsion polymerize 95 parts of methyl methacrylate to parts,
This was atomized by spray drying to obtain reinforcing agent resin particles having an average particle size of 3 μm and an epoxy group content of 2.6% by weight.
60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of a curing agent dicyandiamide, 16 parts by weight of an organic blowing agent azodicarbonamide, and an inorganic filler calcium carbonate 60 parts by weight were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Examples 15 and 16) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to obtain an average particle size of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. In Example 15, a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 16 parts by weight of a curing agent dicyandiamide, 16 parts by weight of an organic blowing agent azodicarbonamide, and 60 parts by weight of an inorganic filler calcium carbonate was used. Example 16 100 parts by weight of bisphenol A type epoxy resin and 100 parts by weight of bisphenol F type epoxy resin
In this example, 200 parts by weight of a bisphenol F epoxy resin was mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All other aspects are the same as in the first embodiment.

(Example 17) 5 parts of glycidyl methacrylate was emulsion-polymerized with 95 parts of methyl methacrylate, which was atomized by spray drying to obtain an average particle diameter of 3 μm.
m, and a reinforcing resin particle having an epoxy group content of 2.6% by weight was obtained. With respect to 30 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of a curing agent dicyandiamide as shown in Tables 1, 2 and 3, and an organic resin 16 parts by weight of a blowing agent azodicarbonamide and 6 parts by weight of an inorganic filler calcium carbonate were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. This is thickness 1
It is extruded into a 5 mm sheet and pseudo-cured with hot air at 110 ° C. for 20 seconds. This composition was previously prepared with a cross-sectional dimension of 50 m.
Length 700 press-molded to mx 50mm
mm, cut and attached to a U-shaped cold-rolled steel plate, and a closing plate is integrated with this U-shaped steel plate member by spot welding to form a box-shaped cross-section member. The epoxy resin composition is left to stand in a drying oven for 20 minutes to foam and fill. The evaluation results using the box-shaped cross-section member assembled in this manner are shown in FIGS. 7, 8, and 9.

Example 18 Example 18 is different from Example 17 in that the blending amount of the methacrylate resin particles was 180 parts by weight with respect to 200 parts by weight of the bisphenol A type epoxy resin. Same as 17.

Comparative Examples 12 and 13 In Comparative Example 12, the methacrylate resin was a bisphenol A epoxy resin 20.
It was blended so as to be 15 parts by weight with respect to 0 parts by weight. In Comparative Example 13, the compounding was performed such that the methacrylate resin was 220 parts by weight with respect to 200 parts by weight of the bisphenol A type epoxy resin. All others are Example 17.
Is the same as

(Examples 19 and 20) In Example 19, 95 parts of methyl methacrylate was emulsion-polymerized with respect to 5 parts of glycidyl methacrylate, and this was atomized by spray drying to obtain an average particle diameter of 3 μm and an epoxy group content of 2 parts. 0.6% by weight
Thus, a reinforcing resin particle was obtained. In Example 20, methyl methacrylate 95 was added to 5 parts of glycidyl methacrylate.
Was subjected to suspension polymerization to obtain reinforcing resin particles having an average particle size of 80 μm. With respect to 60 parts by weight of the thus obtained reinforcing agent resin particles, the liquid bisphenol A type epoxy resin 20
0 parts by weight, 16 parts by weight of a curing agent dicyandiamide, 16 parts by weight of an organic foaming agent azodicarbonamide, and 60 parts by weight of an inorganic filler calcium carbonate were mixed at room temperature using a planetary mixer to obtain an epoxy resin composition. I adjusted things. All others are the same as in the seventeenth embodiment.

(Comparative Examples 14 and 15) In Comparative Example 14, 95 parts of methyl methacrylate was emulsion-polymerized with respect to 5 parts of glycidyl methacrylate, and this was atomized by spray drying to obtain an average particle size of 0.5 μm and an epoxy group-containing content. In Comparative Example 15, 95 parts of methyl methacrylate was suspension-polymerized with 5 parts of glycidyl methacrylate to obtain a reinforcing resin particle having an average particle size of 120 μm. All others are the same as in Examples 19 and 20.

(Examples 21 and 22) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to obtain an average particle diameter of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. With respect to a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, and 60 parts by weight of an inorganic filler calcium carbonate. In Example 21, the curing agent dicyandiamide was added to 10
By weight, in Example 22, 50 parts by weight were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All others are the same as in the seventeenth embodiment.

Comparative Examples 16 and 17 Compared to Examples 21 and 22, the compounding amount of the curing agent dicyandiamide with respect to 200 parts by weight of the liquid bisphenol A type epoxy resin was 4 parts by weight in Comparative Example 16, and 70 parts by weight in Comparative Example 17. All are the same as in Examples 21 and 22, except for the part.

(Examples 23 and 24) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to give an average particle size of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. To a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of a curing agent dicyandiamide, and 60 parts by weight of an inorganic filler calcium carbonate, In Example 23, 2 parts by weight of the blowing agent azodicarbonamide, and in Example 24, 30 parts by weight were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All others are the same as in the seventeenth embodiment.

(Comparative Examples 18 and 19) Compared to Examples 23 and 24, the compounding amount of the organic blowing agent azodicarbonamide with respect to 200 parts by weight of the liquid bisphenol A type epoxy resin was 0.2 parts by weight in Comparative Example 18, In Comparative Example 19, 40
Except for using parts by weight, all are the same as Examples 23 and 24.

(Examples 25 and 26) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to obtain an average particle diameter of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. The mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, and 16 parts by weight of a curing agent dicyandiamide was mixed with an inorganic resin. 10 parts by weight of the filler calcium carbonate in Example 25 and 300 parts by weight in Example 26 were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All others are the same as in the seventeenth embodiment.

(Comparative Examples 20 and 21) Compared to Examples 25 and 26, the compounding amount of the inorganic-filled calcium carbonate with respect to 200 parts by weight of the liquid bisphenol A type epoxy resin was 2 parts by weight in Comparative Example 20, and 2 parts by weight in Comparative Example 21. Except that the amount was 400 parts by weight, all were the same as Examples 25 and 26.

Example 27 Glycidimethacrylate 4
Parts by weight was subjected to emulsion polymerization of 1000 parts of methyl methacrylate, which was atomized by spray drying to obtain an average particle diameter of 3 μm.
Thus, a reinforcing resin particle was obtained. The epoxy group content of the thus obtained reinforcing resin particles is 0.2 parts by weight,
Using a planetary mixer, 60 parts by weight of the particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, 16 parts by weight of a curing agent dicyandiamide, and 60 parts by weight of an inorganic filler calcium carbonate. The mixture was mixed at room temperature to prepare an epoxy resin composition. All others are the same as in the seventeenth embodiment.

(Comparative Example 22) 1000 parts of methyl methacrylate was emulsion-polymerized with respect to 2 parts of glycidyl methacrylate, and this was atomized by spray drying to obtain an average particle diameter of 3 μm.
m of the reinforcing resin particles were obtained. The epoxy resin content of the thus obtained reinforcing agent resin particles was 0.1 part by weight, and all other details were the same as in Example 27.

(Examples 28 and 29) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to give an average particle diameter of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. For a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of an organic blowing agent azodicarbonamide, and 16 parts by weight of a curing agent dicyandiamide, In 28, 60 parts by weight of talc as an inorganic filler, and in Example 29, 60 parts by weight of silica were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All others are the same as in the seventeenth embodiment.

Example 30 Glycidyl acrylate 5
95 parts of methyl acrylate was emulsion-polymerized with respect to parts, and this was atomized by spray drying to obtain reinforcing agent resin particles having an average particle size of 3 μm and an epoxy group content of 2.6% by weight. 60 parts by weight of the thus obtained reinforcing resin particles, 200 parts by weight of a liquid bisphenol A type epoxy resin, 16 parts by weight of a curing agent dicyandiamide, 16 parts by weight of an organic blowing agent azodicarbonamide, and 60 parts by weight of an inorganic filler calcium carbonate 60 The parts by weight were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. All others are the same as in the seventeenth embodiment.

(Examples 31 and 32) To 5 parts of glycidyl methacrylate, 95 parts of methyl methacrylate was subjected to emulsion polymerization, and this was atomized by spray drying to obtain an average particle diameter of 3 parts.
Reinforcement resin particles having a thickness of μm and an epoxy group content of 2.6% by weight were obtained. In Example 31, a mixture of 60 parts by weight of the thus obtained reinforcing resin particles, 16 parts by weight of a curing agent dicyandiamide, 16 parts by weight of an organic blowing agent azodicarbonamide, and 60 parts by weight of an inorganic filler calcium carbonate was used. 100 parts by weight of the A type epoxy resin and 100 parts by weight of the bisphenol F type epoxy resin, and in Example 32, 200 parts by weight of the bisphenol F type epoxy resin were mixed at room temperature using a planetary mixer to prepare an epoxy resin composition. . All other aspects are the same as in the seventeenth embodiment.

(Example 33) As shown in FIG. 2, a gun for applying the epoxy resin composition of the present invention to a preformed steel plate constituting a center pillar / waist portion and a roof rail / center pillar joint portion of a vehicle body. Apply using 11
Pseudo-curing by hot air at 0 ° C for 20 seconds. Then, after assembling the car body using the steel sheet, the car body was washed with a caustic treatment solution to improve the adhesion of the coating film of the car body, and further immersed in an electrodeposition bath for rust prevention treatment. The electrodeposited coating film is baked under the conditions of 20 minutes, and at the same time the foamed resin composition is foamed and cured, thereby filling the box-shaped structural member of the vehicle body and improving the rigidity. At this time, since the foam material had been pseudo-cured in advance, no outflow or falling off was observed in the washing / electrodeposition immersion process.

EXAMPLE 34 As shown in FIG. 3, the epoxy resin composition of the present invention was applied to a preformed steel sheet constituting a center pillar / waist portion and a roof rail / center pillar joint portion of a vehicle body at 110 ° C. The sheet, which has been pseudo-cured by hot air for 20 seconds, is trimmed into a vehicle body shape and placed via an adhesive. Then, after assembling the car body using the steel sheet, the car body was washed with a caustic treatment solution to improve the adhesion of the coating film of the car body, and further immersed in an electrodeposition bath for rust prevention treatment. Baking the electrodeposition coating film under the conditions of 20 minutes, and at the same time, foaming the epoxy resin composition.
By curing, the rigidity is improved by filling the box-shaped structural member of the vehicle body. At this time, since the foam material had been pseudo-cured in advance, no outflow or falling off was observed in the washing / electrodeposition immersion process.

[0050]

As described above, the present invention is derived from bisphenol A and / or bisphenol F in which acrylate or methacrylate polymer resin powder particles containing 0.2% by weight or more of an epoxy group are dispersed. Epoxy resin, an organic foaming material and an inorganic filler are compounded, and an epoxy resin composition having both toughness and pseudo-curability is applied to a pre-formed steel sheet and then pseudo-cured by heat. After assembling a box-shaped member using the steel plate, in the baking process at the time of electrodeposition coating of the car body, it is foamed, filled, or pseudo-cured by heating to make a sheet and form a car body shape After trimming,
It adheres to a preformed steel plate via a stopper such as an adhesive or a clip to prevent it from falling off and flowing out. After assembling a box-shaped member using the steel plate, foaming occurs during the baking process during body electrodeposition coating By filling, it becomes possible to reinforce the body frame lightly. This is expected to improve the riding comfort of vehicles and reduce noise and vibration. In addition, by filling a highly rigid foam in a box-shaped closed-section member, it is expected to have an energy absorbing effect at the time of vehicle collision. Can be.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for measuring an improvement in rigidity of a box-shaped cross-section member according to the present invention.

FIG. 2 is a process chart showing a method of reinforcing a vehicle body, which is subjected to pseudo-curing after the application of the epoxy resin composition according to the present invention.

FIG. 3 is a process chart showing a method of reinforcing a vehicle body, which is obtained by pseudo-curing the epoxy resin composition according to the present invention in advance and forming a sheet, and then cutting out and attaching the sheet.

FIG. 4 is a diagram showing evaluation results of Examples 1 to 5 and Comparative Examples 1 to 4.

FIG. 5 is a diagram showing evaluation results of Examples 6 to 10 and Comparative Examples 5 to 8.

FIG. 6 is a diagram showing evaluation results of Examples 11 to 16 and Comparative Examples 9 to 11.

FIG. 7 is a diagram showing evaluation results of Examples 17 to 21 and Comparative Examples 12 to 15.

FIG. 8 is a diagram showing evaluation results of Examples 22 to 26 and Comparative Examples 16 to 19.

FIG. 9 is a diagram showing evaluation results of Examples 27 to 32 and Comparative Examples 20 to 22.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Epoxy resin composition 2 Box-shaped sectional member

Claims (4)

[Claims] 1. A powdery acrylate or methacrylate polymer (B) having an average particle size in the range of 1 to 100 μm per 100 parts by weight of an epoxy resin derived from (A) bisphenol A and / or bisphenol F.
100 parts by weight, (C) 3 to 30 parts by weight of a thermally activated curing agent for epoxy resin, (D) 0.5 to 0.5 parts of a thermally decomposable organic foaming agent
An epoxy resin composition for reinforcing a vehicle body, comprising 15 parts by weight and (E) 3 to 150 parts by weight of an inorganic filler. 2. The epoxy resin composition for reinforcing a vehicle body according to claim 1, wherein the acrylate or methacrylate polymer (B) is a resin powder particle containing 0.2% by weight or more of an epoxy group. 3. A box-shaped structural member for a vehicle body.
Or after applying the epoxy resin-based composition for reinforcing a vehicle body according to 2 to a preformed steel sheet, pseudo-hardening by heating to prevent falling off and outflow, and assembling a box-shaped member using the steel sheet. , Foaming in the baking process during body electrodeposition painting,
A method for reinforcing a vehicle body, which comprises filling a box-shaped structural member of the vehicle body to improve rigidity. 4. A box-shaped structural member for a vehicle body.
Alternatively, the epoxy resin composition for reinforcing a vehicle body described in 2 is pseudo-cured by heating, trimmed into a vehicle body shape, and then adhered to a preformed steel plate via a stopper such as an adhesive or a clip to drop off. A body characterized by preventing leakage, assembling a box-shaped member using the steel plate, and then foaming in a baking process at the time of electrodeposition coating of the body, filling the box-shaped structural member of the body to improve rigidity. Reinforcement method.