JP6927928B2 - Adhesion method for resin exterior members - Google Patents

Description

The present invention relates to a method of adhering a painted resin exterior member, and more specifically, constitutes a vehicle exterior component such as a resin door (front door, rear door, back door, etc.) or a resin hood (bonnet, etc.). The present invention relates to a method of adhering a resin exterior member.

Resin exterior parts that make up vehicles such as automobiles include, for example, polypropylene (PP) outer panel members (members that make up the design surface) that are placed on the outside of the car, and glass fiber reinforced polypropylene that is placed inside the car. It is manufactured by adhering an inner panel member (reinforcing material) made of (PPGF). A special rubber-based adhesive is used to bond PP and PPGF in order to alleviate the difference in linear expansion coefficient between the two. However, since this rubber-based adhesive is inferior in adhesion to PP, a primer for adhesive assistance (for example, an organic solvent-type primer for a polypropylene material) has been conventionally used for the purpose of improving the adhesiveness between PP and the rubber-based adhesive. A rubber-based adhesive was applied to the PP by interposing it.

In the above bonding process, first, an adhesive primer is applied to the bonding portion on the back side of the outer panel member (that is, the bonding portion with the inner panel member), and then the design surface of the outer panel member (front surface of the outer panel member). The sides) are generally painted. When the organic solvent type primer paint, the organic solvent type base paint, and the organic solvent type clear paint are sequentially applied to form the design surface of the outer panel member, the atomized paint is applied on the surface of the primer coating film for adhesion assistance. This also causes a part of the adhesion auxiliary primer to be redissolved, resulting in a mixed layer of the adhesion auxiliary primer and the paint for forming the design surface. Then, the cohesive force of the adhesion assisting primer is reduced, and there is a problem that poor adhesion between the outer panel member and the adhesion assisting primer occurs. Therefore, after applying the adhesion-assisting primer to the outer panel member, masking treatment is performed on the surface so that the adhesion-assisting primer does not peel off even in the cold-heat cycle test, etc., and the design is placed on the adhesion-assisting primer. It was necessary to protect the surface forming paint from being applied, which required a great deal of labor and cost.

For example, in Patent Document 1, the surface of a glass fiber reinforced polypropylene molded product is surface-treated with a flame, a material that easily adheres to polypropylene is applied to the surface, and then a material that easily adheres to an adhesive is applied thereto. , A method of stably and firmly adhering a glass fiber reinforced polypropylene molded product by applying an adhesive and adhering an adherend has been proposed.

Japanese Unexamined Patent Publication No. 2003-0270112

However, even in the case of bonding using the technique of Patent Document 1, there is a similar problem in the formation of the design surface in the outer panel member.

An object of the present invention is to solve the above-mentioned problems and to stably and firmly bond the outer panel member and the inner panel member, which are resin exterior members, without performing a masking treatment after applying the adhesion auxiliary primer. It is an object of the present invention to provide a method for adhering a resin exterior member.

As a result of diligent studies, the present inventors have used a water-based primer paint as a primer paint that constitutes the design surface of the outer panel member that constitutes the resin exterior part, and used the water-based primer paint as the adhesive portion of the outer panel member with the inner panel member. The present invention is solved by finding that the above problems can be solved by applying an adhesion auxiliary primer and then forming a coating film on the design surface of the outer panel member in the order of a water-based primer coating material, a base coating material, and a clear coating material. It came to.

That is, the present invention is characterized by the following (1) to (3).
(1) An adhesive method for an outer panel member made of resin, in which the outer panel member and the inner panel member constituting the resin exterior component are adhered, and an adhesive auxiliary primer is applied to the adhesion portion of the outer panel member with the inner panel member. Then, at least one of the water-based primer paint, the water-based base paint, and the organic solvent-type base paint, and the organic solvent-type clear paint are sequentially wet-on-wet on the design surface of the outer panel member. After being heat-cured, a rubber-based adhesive is applied to the bonding portion of the outer panel member provided with the bonding assisting primer to bond the inner panel member. Method.
(2) The method for adhering a resin exterior member according to (1), wherein at least one of the outer panel member and the inner panel member is made of a polypropylene-based resin material.
(3) When the adhesive primer is coated so that the dry film thickness is 30 μm and cured by heating at 80 ° C. for 20 minutes, the molecular weight between crosslinks of the cured coating film is 10,000 g / mol or less. The method for adhering a resin exterior member according to (1) or (2) above, wherein the glass transition temperature is 50 ° C. or higher.

According to the bonding method of the present invention, it is not necessary to perform a masking treatment after applying the bonding assisting primer, which can contribute to reduction of man-hours and costs, and the resin exterior member can be stably and firmly bonded.

Hereinafter, the method for adhering the resin exterior member of the present invention will be described in detail.
In the present specification, for convenience of explanation, the side of the vehicle facing the outside of the vehicle may be referred to as the "front side", and the side facing the inside of the vehicle may be referred to as the "back side".

The resin exterior parts obtained by the method of bonding the resin exterior members of the present embodiment are the parts constituting the exterior of the vehicle, the outer panel member which is an external structural member facing the outside of the vehicle, and the inside facing the inside of the vehicle. It is provided with an inner panel member which is a structural member, and is configured by adhering them to each other with an adhesive. The method of adhering the resin exterior member of the present embodiment is a method of adhering the resin exterior member constituting the resin exterior component, that is, the outer panel member and the inner panel member.

The inner panel member is formed of, for example, a resin material containing a highly rigid resin such as glass fiber reinforced polypropylene (PPGF), carbon fiber reinforced polypropylene (PPCF) or other inorganic filler reinforced polypropylene, or SMC (Sheet Molding Compound). Is preferable. These may be used individually by 1 type, or may be used in combination of 2 or more type. Above all, from the viewpoint of rigidity, weight and cost, the inner panel member is preferably formed of a polypropylene-based resin material containing polypropylene, more preferably formed of a resin material containing an inorganic filler-reinforced polypropylene, and glass. It is particularly preferably formed from a resin material containing fiberglass reinforced polypropylene.

The outer panel member is formed of a resin material having a larger coefficient of linear expansion than the inner panel member. Examples of the resin material constituting the outer panel include a resin material containing a highly flexible resin such as polypropylene (PP), acrylonitrile butadiene styrene (ABS), polycarbonate, polyester, and polyamide. These may be used individually by 1 type, or may be used in combination of 2 or more type. Above all, from the viewpoint of flexibility, weight and cost, the outer panel member is preferably formed of a polypropylene-based resin material containing polypropylene.

In the method of adhering the resin exterior member of the present embodiment, an adhesive primer is applied to the adhesion portion of the outer panel member with the inner panel member, and then at least the design surface of the outer panel member is coated with a water-based primer paint and a water-based base. At least one base paint of the paint and the organic solvent type base paint, and the organic solvent type clear paint are sequentially applied wet-on-wet, heat-cured, and then adhered with a primer for adhering the outer panel member. This includes applying a rubber-based adhesive to the site to bond the inner panel member.
Hereinafter, each step will be described in sequence.

In the present embodiment, first, an adhesion assisting primer is applied to an adhesion portion of the outer panel member with the inner panel member (adhesion portion on the back side of the outer panel member).

As the adhesion auxiliary primer, a conventionally known organic solvent type primer applicable to the resin material constituting the outer panel member can be applied without particular limitation. Examples of the adhesion auxiliary primer include conventionally known organic solvent-diluted paints containing chlorinated polypropylene, acrylic-modified chlorinated polypropylene, and the like. In particular, as an adhesive primer, from the viewpoint of ensuring cohesive force and adhesiveness, the cured coating film is crosslinked when it is coated so that the dry film thickness is 30 μm and cured by heating at 80 ° C. for 20 minutes. Primers having an intermolecular weight of 10,000 g / mol or less, preferably 9,000 g / mol or less, and a glass transition temperature of 50 ° C. or higher, preferably 55 to 65 ° C. can be preferably used. The lower limit of the intercrosslinking molecular weight of the cured coating film is not particularly limited, but is preferably 6,000 g / mol or more, and more preferably 7,000 g / mol or more.

In the present specification, the glass transition temperature is determined by using a forced vibration type solid viscoelasticity measuring device (for example, FT rheology spectrumr "Rheogel E-400" (manufactured by UBM Co., Ltd.)) for the cured coating film. It is a dynamic glass transition temperature measured as a temperature showing the maximum value of tan δ (loss elastic modulus / storage elastic modulus) in dynamic viscoelasticity measurement measured under the conditions of 110 hertz and a heating rate of 4 ° C./min. ..

Further, in the present specification, the intercrosslinking molecular weight was obtained by applying the minimum value of the storage elastic modulus obtained when measuring the glass transition temperature of the cured coating film to the following rubber viscoelastic theoretical formula (Equation 1). It is a theoretically calculated value.
Equation 1: Mc = 3ρRT / Emin
here,
Mc: Molecular weight between crosslinks (g / mol),
ρ: Density of sample coating film (kg / m ³ ),
R: Gas constant (8.314J / K / mol),
T: Absolute temperature (K) when the storage elastic modulus is Emin,
Emin: Minimum storage modulus (Pa)
Is.

The adhesion auxiliary primer can be applied by a usual method, and examples thereof include spray coating, electrostatic coating, brush coating, roller coating, dip coating, and the like, but in general, spray coating and brush coating are preferable. The coating film thickness is preferably in the range of 7 to 35 μm, particularly preferably in the range of 10 to 15 μm, based on the dry coating film. When the thickness of the dry coating film of the adhesion assisting primer is 7 μm or more, the adhesiveness to the inner panel member via the rubber adhesive can be enhanced, and when the thickness is 35 μm or less, the adhesion assisting primer is used. It is possible to secure the adhesiveness between the coating film formed by the above and the outer panel member.

After applying the adhesive primer to the adhesive portion on the back side of the outer panel member, it is preferable to leave it at room temperature for about 2 to 10 minutes to dry it until the adhesive primer coating film becomes dry to the touch.

Next, at least one of the water-based primer paint, the water-based base paint, and the organic solvent-type base paint, and the organic solvent-type clear paint are sequentially wetted on the design surface of the outer panel member (the front surface of the outer panel member). Painting is performed on-wet (that is, a method in which the paint is continuously applied with the surface of the coating film uncured without forced drying during the coating process of each paint).
When applying three paints for design shaping, that is, primer paint, base paint, and clear paint, on the design surface of the outer panel member, depending on the painting method, parts other than the one where the paint film is planned to be formed, for example, for adhesion assistance The design-forming paint may adhere to the part to which the primer is applied. However, in the present embodiment, by using the water-based primer paint as the primer paint, even if the above three atomized paints adhere to the adhesion auxiliary primer surface applied to the back side adhesive portion of the outer panel member, Adhesion-assisting primer It is presumed that the coated surface does not re-dissolve and mixed layers can be prevented, and that peeling of the adhesion-assisting primer from the outer panel member can be suppressed.

The water-based primer paint is applied for the purpose of ensuring adhesion to the outer panel member. As the water-based primer paint, for example, a water-based polyolefin resin or a water-based acrylic resin is used as a film-forming component, and further, a cross-linking agent, a coloring pigment, an extender pigment, a conductive pigment, a curing catalyst, a rheology control agent, an antifoaming agent, and an organic material. Conventionally known water-soluble or water-dispersible paints in which ordinary paint additives such as solvents are appropriately selected and blended can be used. As the water-based primer coating material, one type may be used alone, or two or more types may be used in combination.

The water-based primer coating can be applied by a usual method, and examples thereof include spray coating, electrostatic coating, brush coating, roller coating, dip coating, and the like, and spray coating is generally preferable. The coating film thickness is preferably in the range of 5 to 20 μm, particularly preferably in the range of 7 to 15 μm, based on the dry coating film. When the thickness of the dry coating film of the water-based primer coating film is 5 μm or more, adhesiveness, concealment property and the like can be ensured, and when the thickness is 20 μm or less, film strength and the like can be ensured.

In the present embodiment, it is preferable that after the water-based primer coating is applied, the coating film to be formed is not substantially cured, and is air-dried as it is by, for example, air blow, and then the base coating is applied.

The base paint applied to the surface of the water-based primer coating film is applied for the purpose of imparting cosmetic properties. As the base paint, for example, a thermocurable resin composition such as an amino-acrylic resin type, an amino-alkyd resin type, or an amino-polyester resin type is used as a film-forming component, and if necessary, a colored paint, a metallic pigment, or the like is used. Pigments: Use conventionally known water-soluble or water-dispersible water-based base paints or organic solvent-type base paints in which paint additives such as curing catalysts, rheology control agents, defoaming agents, and organic solvents are appropriately selected and blended. be able to. As the base paint, one type may be used alone, or two or more types may be used in combination.

The base coating material can be applied by a usual method, and examples thereof include spray coating, brush coating, electrostatic coating, roller coating, dip coating, and the like, and in general, spray coating and electrostatic coating are preferable. The coating film thickness is preferably in the range of 5 to 30 μm, particularly preferably in the range of 10 to 20 μm, based on the dry coating film. When the thickness of the dry coating film of the base paint is within this range, designability and the like can be ensured.

In the present embodiment, it is preferable that after the base paint is applied, the coating film to be formed is not substantially cured, and is, for example, air-dried as it is at room temperature with an air blow or the like, and then the organic solvent type clear paint is applied. ..

As the organic solvent type clear paint, a paint that forms a colorless or colored transparent coating film can be used. As the organic solvent type clear paint, for example, a thermosetting resin composition such as an isocyanate-acrylic resin type, an amino-acrylic resin type, or an amino-polyester resin type is used as a film-forming component, and if necessary, an ultraviolet absorber is used. An organic solvent-based thermosetting paint obtained by appropriately blending paint additives such as a light stabilizer, a curing catalyst, a coating surface conditioner, a rheology control agent, an antioxidant, and a wax can be used. The organic solvent type clear paint may be used alone or in combination of two or more.

The organic solvent type clear coating material can also be applied by various usual methods, and examples thereof include spray coating, brush coating, electrostatic coating, roller coating, dip coating, and generally spray coating and electrostatic coating. Is preferable. The coating film thickness is preferably in the range of 20 to 80 μm, particularly preferably in the range of 25 to 50 μm, based on the dry coating film. When the thickness of the dry coating film of the organic solvent type clear paint is 20 μm or more, weather resistance, gloss, etc. can be ensured, and when the thickness is 80 μm or less, liquid dripping when the organic solvent type clear paint is applied, etc. Can be prevented.

As described above, the water-based primer paint, the base paint, and the organic solvent type clear paint are sequentially applied, and if necessary, left at room temperature and then heated to cure the three-layer coating (3 coats, 1 bake). As a condition of heat curing, it can be cured at the same time by heating at a temperature in the range of about 60 to about 120 ° C., particularly about 70 to about 100 ° C., usually for about 20 to about 40 minutes.
Examples of the heating means include hot air heating, infrared heating, high frequency heating and the like.

Next, a rubber-based adhesive is applied to the bonding portion provided with the bonding assisting primer of the outer panel member to bond the inner panel member.

The rubber-based adhesive can be used without particular limitation as long as it exhibits rubber-like properties. For example, natural rubber, chloroprene rubber, styrene-butadiene copolymer rubber (SBR), isobutylene rubber, butyl rubber, styrene-isoprene- Liquid adhesive containing rubber components such as styrene block copolymer rubber (SIS), styrene-butadiene-styrene block copolymer rubber (SBS), butadiene-acrylonitrile copolymer rubber (NBR), butadiene rubber (BR), urethane rubber, etc. Can be mentioned. Only one type of rubber component may be used, or two or more types may be used in combination. A urethane rubber adhesive is particularly preferable.

In the present embodiment, an adhesive primer may be applied before applying the rubber-based adhesive, if necessary, in order to ensure the adhesiveness of the rubber-based adhesive. As the adhesive primer, an isocyanate-based primer can be used. As the adhesive primer, one type may be used alone, or two or more types may be used in combination.

A resin exterior part can be obtained by adhering the inner panel member to the formed rubber-based adhesive surface so as to be in close contact with the inner panel member and heating the inner panel member as necessary. As the heating conditions, it is preferable to heat at 30 to 80 ° C., preferably 40 to 50 ° C. for 5 to 20 minutes, preferably 10 to 15 minutes. Examples of the heating means include hot air heating, infrared heating, high frequency heating and the like.
In addition, you may pressurize at the time of close contact. By pressurizing, the outer panel member and the inner panel member can be more firmly adhered to each other. Here, the pressing force may be appropriately adjusted depending on the size and shape of the joint surface.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Preparation of test specimen>
The adhesion-assisting primers used in the following examples, comparative examples and reference examples are as follows.
Adhesion auxiliary primer A: Solvent system, molecular weight between crosslinks 8000 g / mol, glass transition temperature 56 ° C.
Adhesion auxiliary primer B: Solvent system, molecular weight between crosslinks 8000 g / mol, glass transition temperature 45 ° C.

(Example 1)
A polypropylene plate (length 2 cm × width 10 cm × thickness 3 mm) was used as the outer panel member. Adhesion-assisting primer A was applied to one side (back side) of the polypropylene plate so as to have a dry film thickness of 12 μm, and dried at room temperature for 3 minutes. After that, the water-based primer paint "ASX380-1 D35" (manufactured by Kansai Paint Co., Ltd.) is sprayed on one side (surface) on the opposite side of the polypropylene plate and the coated surface of the adhesive primer A so that the dry film thickness is 15 μm. After painting and preheating at 80 ° C for 5 minutes, the water-based base paint "WBC713D-3 S28" (manufactured by Kansai Paint Co., Ltd.) is spray-coated on the water-based primer coating so that the dry film thickness is 15 μm, and then 80 ° C. After preheating for 5 minutes, a two-component solvent-based clear paint "Soflex 8538D" (manufactured by Kansai Paint Co., Ltd.) was electrostatically atomized onto the aqueous base coating film so as to have a dry film thickness of 30 μm. Then, it was heated at 100 degreeC for 30 minutes, and the three-layer coating film was cured at the same time.

In a test assuming an actual resin exterior member, the adhesive primer A was applied to one side (back side) of a polypropylene plate (length 2 cm x width 10 cm x thickness 3 mm) as an outer panel member so that the dry film thickness was 12 μm. After coating on the surface and drying at room temperature for 3 minutes, a water-based primer paint, a water-based base paint, and a two-component solvent-based clear paint are sequentially applied to one side (surface) on the opposite side of the polypropylene plate, and these three-layer coatings are applied. Although it is heat-cured, in order to be used for the simple peeling test described later, a water-based primer paint, a water-based base paint, and a two-component solvent-based clear paint are applied in sequence on the surface of the primer for adhesion assistance, and a three-layer coating is applied. By forming it, it was made a strict condition.

Next, the adhesive primer "RC- 50E ”(manufactured by Yokohama Rubber Co., Ltd.) is applied to a dry film thickness of 5 μm, dried at room temperature for 5 minutes, and then a urethane rubber-based adhesive is applied as a rubber-based adhesive to the primer-coated surface for the adhesive. It was applied so that the dry film thickness was 5 mm. On the other hand, one side of a glass fiber reinforced polypropylene plate (length 2 cm x width 10 cm x thickness 3 mm) as an inner panel member is subjected to plasma treatment, and then the adhesive primer "RC-50E" (manufactured by Yokohama Rubber Co., Ltd.) is dried. It was applied so as to have a film thickness of 5 μm, and dried at room temperature for 5 minutes. Then, the primer-coated surface for the adhesive of the glass fiber reinforced polypropylene plate is brought into close contact with the rubber-based adhesive surface provided on the polypropylene plate to adhere to each other, and heated at 40 ° C. for 20 minutes to obtain the test piece (1). rice field.

(Example 2)
A test body (2) was obtained in the same manner as in Example 1 except that the adhesion auxiliary primer B was used instead of the adhesion auxiliary primer A in Example 1.

(Comparative Example 1)
A polypropylene plate (length 2 cm × width 10 cm × thickness 3 mm) was used as the outer panel member. Adhesion-assisting primer A was applied to one side (back side) of the polypropylene plate so as to have a dry film thickness of 12 μm, and dried at room temperature for 3 minutes. After that, the organic solvent-based primer paint "Soflex 3210 CD" (manufactured by Kansai Paint Co., Ltd.) was applied to the opposite side (surface) of the polypropylene plate and the coated surface of the adhesive primer A so that the dry film thickness was 15 μm. After spray coating and allowing to stand for 2 minutes, the organic solvent-based base paint "Soflex 606D S28" (manufactured by Kansai Paint Co., Ltd.) is electrostatically atomized on the organic solvent-based primer coating so that the dry film thickness is 15 μm. After painting and preheating at 80 ° C for 5 minutes, a two-component solvent-based clear paint "Soflex 500DL" (manufactured by Kansai Paint Co., Ltd.) is electrostatically applied on an organic solvent-based base coating so that the dry film thickness is 30 μm. It was atomized and painted. Then, it was heated at 100 degreeC for 30 minutes, and the three-layer coating film was cured at the same time.

Next, the adhesive primer "RC- 50E ”(manufactured by Yokohama Rubber Co., Ltd.) is applied to a dry film thickness of 5 μm, dried at room temperature for 5 minutes, and then a urethane rubber-based adhesive is applied as a rubber-based adhesive to the primer-coated surface for the adhesive. It was applied so that the dry film thickness was 5 mm. On the other hand, one side of a glass fiber reinforced polypropylene plate (length 2 cm x width 10 cm x thickness 3 mm) as an inner panel member is subjected to plasma treatment, and then the adhesive primer "RC-50E" (manufactured by Yokohama Rubber Co., Ltd.) is dried. It was applied so as to have a film thickness of 5 μm, and dried at room temperature for 5 minutes. Then, the primer-coated surface for the adhesive of the glass fiber reinforced polypropylene plate is brought into close contact with the rubber-based adhesive surface provided on the polypropylene plate to adhere to each other, and heated at 40 ° C. for 20 minutes to obtain the test piece (3). rice field.

(Comparative Example 2)
A test body (4) was obtained in the same manner as in Comparative Example 1 except that the adhesion auxiliary primer B was used instead of the adhesion auxiliary primer A in Comparative Example 1.

(Reference example 1)
A polypropylene plate (length 2 cm × width 10 cm × thickness 3 mm) was used as the outer panel member. Adhesion-assisting primer A was applied to one side (back side) of the polypropylene plate so as to have a dry film thickness of 12 μm, and dried at room temperature for 3 minutes. After that, the structural agent primer "RC-50E" (manufactured by Yokohama Rubber Co., Ltd.) was applied to the center of the adhesive auxiliary primer A surface, specifically in the range of 2 cm in length and 8 cm in width, so that the dry film thickness was 5 μm. Then, after drying at room temperature for 5 minutes, a urethane rubber-based adhesive as a rubber-based adhesive was applied to the adhesive primer-coated surface so as to have a dry film thickness of 5 mm. On the other hand, one side of a glass fiber reinforced polypropylene plate (length 2 cm x width 10 cm x thickness 3 mm) as an inner panel member is subjected to plasma treatment, and then the adhesive primer "RC-50E" (manufactured by Yokohama Rubber Co., Ltd.) is dried. It was applied so as to have a film thickness of 5 μm, and dried at room temperature for 5 minutes. Then, the primer-coated surface for the adhesive of the glass fiber reinforced polypropylene plate is brought into close contact with the rubber-based adhesive surface provided on the polypropylene plate to adhere to each other, and heated at 40 ° C. for 20 minutes to obtain a test piece (5). rice field.

(Reference example 2)
A test body (6) was obtained in the same manner as in Reference Example 1 except that the adhesion auxiliary primer B was used instead of the adhesion auxiliary primer A in Reference Example 1.

<Simple peeling test>
Ten specimens (1) to (6) were left at 20 ° C. and 65% RH (relative humidity) for 24 hours. After that, in the gap between the polypropylene plate as the outer panel member and the glass fiber reinforced polypropylene plate as the inner panel member, that is, in the gap of the portion where the rubber adhesive is applied, a spacer (thickness 7 mm or 7 mm in thickness) of each thickness for peeling is used. 8 mm) was sandwiched and left in this state in a constant temperature bath at 80 ° C. for 72 hours. Each spacer has a thickness of +2 mm or +3 mm, which is larger than the thickness of the rubber adhesive (5 mm). By inserting the spacer into the gap between the polypropylene plate and the glass fiber reinforced polypropylene plate, stress is applied to both. It will take.
Then, the test piece was taken out from the constant temperature bath, and the presence or absence of peeling between the polypropylene plate and the adhesion auxiliary primer was visually confirmed and evaluated based on the following evaluation criteria. The results are shown in Table 1.
〔Evaluation criteria〕
◯: Number of test bodies with peeling is 0 Δ: Number of test bodies with peeling is 1 to 4 ×: Number of test bodies with peeling is 5 or more

From the comparison between Example 1 and Comparative Example 1, in Example 1, there was no peeling between the polypropylene plate and the adhesion auxiliary primer even in the peeling test with a spacer having a thickness of 8 mm in which a stronger stress was applied to the outer panel member and the inner panel member. , Good adhesion was maintained. Further, from Examples 1 and 2, it was shown that when the glass transition temperature of the adhesion auxiliary primer is 50 ° C. or higher, the outer panel member and the inner panel member of the resin exterior component can be adhered more firmly. From the comparison between Example 2 and Comparative Example 2, even when the glass transition temperature of the adhesion assisting primer is lower than 50 ° C., the outer panel member and the adhesion assisting primer can be adhered by the bonding method of the present embodiment. It was found that the adhesiveness with and can be improved.

Claims (3)

This is a method of adhering resin exterior members, which adheres the outer panel members and inner panel members that make up the resin exterior parts.
An adhesive primer is applied to the bonding portion of the outer panel member with the inner panel member, and then at least one of the water-based primer paint, the water-based base paint, and the organic solvent-type base paint is applied to the design surface of the outer panel member. The two base paints and the organic solvent type clear paint are sequentially applied wet-on-wet and cured by heating, and then a rubber-based adhesive is applied to the adhesive portion of the outer panel member provided with the adhesive auxiliary primer. A method of bonding a resin exterior member, which comprises bonding an inner panel member. The method for adhering a resin exterior member according to claim 1, wherein at least one of the outer panel member and the inner panel member is made of a polypropylene-based resin material. When the adhesive primer was applied so as to have a dry film thickness of 30 μm and cured by heating at 80 ° C. for 20 minutes, the intercrosslinked molecular weight of the cured coating film was 10,000 g / mol or less. The method for adhering a resin exterior member according to claim 1 or 2, wherein the glass transition temperature is 50 ° C. or higher.