JP3522805B2 - Polyolefin molded body coated with non-yellowing primer for automobile - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin molded article coated with a non-yellowing primer for automobiles.

[0002]

2. Description of the Related Art As a conventional primer for polypropylene (PP) base material, there are, for example, the followings.
A polyolefin resin or a chlorinated polyolefin resin having a similar solubility parameter (SP value) is applied to the resin of the primer for PP base material in order to secure the adhesion of the coating film to the PP base material. Further, the polyolefin resin or the chlorinated polyolefin resin is modified with a compound having a polar group such as epoxy or maleic anhydride, or an epoxy resin is mixed, in order to secure the adhesion with the top coating film.

[0003]

However, in such a conventional primer for a PP base material, the PP resin used as the base material contains an antioxidant, an ultraviolet absorber, a light stabilizer and the like. However, since it is not formulated to prevent migration of these additive components to the primer, in the case of light-colored top-coating, the top-coating film turns yellow due to the influence of heat, etc. There was a problem.
The yellowing of the coating film is caused by the hindered phenolic antioxidant contained in the PP base resin reacting with the chlorohydrin compound contained as a by-product of the epoxy resin used in the primer to increase the yellowing degree. Hydrogen chloride generated by the dehydrochlorination reaction is a light stabilizer contained in the top coating film,
For example

[Chemical 2] It further reacts with the terminal N group of the 6-membered ring compound and is further yellowed.

[0004]

The present invention has been made by paying attention to such problems in the prior art. The hindered pheno
Epoxy on a polypropylene substrate containing a polyol-based antioxidant.
In the case of a polyolefin molded product made by coating a primer containing a resin and a topcoat paint,

[Chemical 3] A non-yellowing primer for an automobile, characterized in that it contains a tin compound represented by the formula (R ₁ and R ₂ are alkyl groups and R ₃ and R ₄ are laurate, malate or mercaptide groups). The present invention relates to a coated polyolefin molded body. In the present invention, it is preferable to use a polyolefin resin or a chlorinated polyolefin resin and an epoxy resin as the primer resin.

[0005]

In the present invention, the primer contains an epoxy resin.
In addition , it is preferable that the resin further contains polyolefin resin or chlorinated polyolefin resin and epoxy resin.
Good The cause of yellowing of the coating film is that chlorohydrin and P contained as a by-product of the epoxy resin used for the primer
What is generated by reacting with a hindered phenolic antioxidant contained in a P substrate to form a quinone structure, and a terminal N group of a light stabilizer (six-membered ring compound) contained in a top coat film It reacts and further turns yellow.
In the present invention, by incorporating the tin compound represented by [Chemical Formula 3] into the primer, the tin in the compound is used for the hindered phenolic antioxidant contained in the PP base resin and the primer. During the reaction with the chlorohydrin form contained as a by-product of the epoxy resin, it reacts first with the chlorhydrin form, so that the above-mentioned antioxidant does not produce the quinone structure that causes yellowing. Furthermore, tin in the primer reacts with chlorine (Cl) to cause SnCl
_{Since it is 2} , generation of hydrogen chloride can be prevented. Therefore, it is possible to prevent the reaction between various additives contained in the top coating film and hydrogen chloride.

As the tin compound of [Chemical Formula 3] used in the present invention,
For dinormal octyl tin dilaurate, dinorma
Luoctyl tin malate type, dibutyl tin dilaurate type,
Dibutyltin malate-based, dinormal octyltin dimerca
Ptide, octyltin mercaptide, dibutyltin
Examples include mercaptide series. Also, R in [Chemical 3] ₁
And R₂As normal octyl, R₃And R_Four
For this, laurate, malate, mercaptide, etc. are preferred.
It is used well.

For the primer, the tin compound represented by [Chemical Formula 3] is used in an amount of 0.5 to 3 relative to the solid content of the primer resin.
It is preferable to contain 0% by weight. When the amount of the tin compound added is less than 0.5% by weight, the amount of tin is small and the reaction with the chlorohydrin body and chlorine is not sufficiently performed, so that the effect of preventing yellowing of the coating film is small. If it exceeds 30% by weight, blisters (coating swelling) occur in the coating film after the water resistance test and the adhesion of the coating film decreases.

Further, the primer resin used in the present invention comprises a polyolefin resin or a chlorinated polyolefin resin and an epoxy resin, and preferably the polyolefin resin or the chlorinated polyolefin resin has a polar group such as epoxy or maleic anhydride. Modified with compound or mixed with epoxy resin. A polyolefin resin having an SP value similar to that of the PP substrate ensures adhesion to the substrate, and epoxy or maleic anhydride having a polar group ensures adhesion to the overcoat film.

[0009]

EXAMPLES The present invention will be described below with reference to examples and comparative examples. In the examples, "parts" means "parts by weight" unless otherwise specified.

Examples 1 to 7 and Comparative Example 1 The following formula for tin compounds

[Chemical 4] The dinormaloctyltin malate represented by (Adecastap OT-9, manufactured by Asahi Denka Co., Ltd.) was used to prepare the primers of Examples 1 to 7 and Comparative Example 1 with the formulations shown in Table 1. Next, eight polypropylene (PP) base materials (TX-1180) manufactured by Mitsubishi Petrochemical Co., Ltd. were degreased using isopropyl alcohol. Each of the above primers is coated on each substrate so that the dry film thickness is 5 μm, and the temperature is 90 ° C.
After baking and drying for 20 minutes, a urethane-modified melamine acrylic topcoat paint was applied so that the dry film thickness was 30 μm, and baking and drying was carried out at 120 ° C. for 20 minutes to obtain a coated plate. Using these finished coated plates, a coating film performance test was conducted by the following evaluation method.

Evaluation method (1) The heat-resistant yellowing test piece was left in a drying oven kept at 90 ° C. for 240 hours,
The b value is measured 1 hour after the removal. Yellowing degree (Δb) is
It is calculated by the following formula. Δb = (b value after heat resistance test) − (b value before heat resistance test) Measuring device: CR-200 (manufactured by Minolta Co., Ltd.) Make 100 squares (10 x 10), adhere the adhesive tape to the eyes of the bag, keep one end of the tape perpendicular to the effective surface, and instantaneously separate it at a speed of 0.5 m / s or more. Determine the adhesion of the coating film to the substrate. (3) Immerse the test piece in water-resistant deionized water or distilled water. Put in a constant temperature water bath kept at 40 ° C. for 240 hours. The film is taken out and then allowed to stand at room temperature for 1 hour, after which the coating film is tested for adhesion. The adhesion test of the coating film is in accordance with (2) above.

Table 1 shows the above evaluation results together.

[Table 1]

[0013]

As it has been described above, according to the present invention, the present invention, the ratio
A polyolefin molded product obtained by coating a primer containing an epoxy resin and a topcoat paint on a polypropylene substrate containing a binder phenolic antioxidant, characterized in that the primer contains a tin compound represented by [Chemical Formula 3]. Is a polyolefin molded article coated with a non-yellowing primer for automobiles, preferably 0.5 to 3
Since 0% by weight is added, (1) yellowing of the coating film on the polypropylene base material can be prevented, (2) it is possible to expand the adoption of light coloring, and (3) diversion of inexpensive additives It is possible to obtain the excellent effect that the cost of the polypropylene base material can be reduced.

Front Page Continuation (72) Inventor Masahiko Yamanaka 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Kentaro Watanabe 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72 ) Inventor Isamu Hara 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP-A-5-59327 (JP, A) JP-A-51-109944 (JP, A) JP-A- 62-192916 (JP, A) JP-B 47-13305 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 5/00 C09D 157/00 C09D 163/00 C08J 7 / 00

Claims (4)

(57) [Claims] 1. A hindered phenolic antioxidant is included.
In a polyolefin molded article obtained by coating a primer containing an epoxy resin and a top coating material on a polypropylene substrate, the primer has the following formula: A non-yellowing primer for an automobile, characterized in that it contains a tin compound represented by the formula (R ₁ and R ₂ are alkyl groups and R ₃ and R ₄ are laurate, malate or mercaptide groups). Painted polyolefin molding. 2. A polyolefin molded article coated with a non-yellowing primer for automobiles according to claim 1, wherein the top coating film contains a 6-membered ring compound having a terminal N group as a light stabilizer. 3. The automobile battery according to claim 1, wherein the tin compound represented by [Chemical Formula 1] is contained in an amount of 0.5 to 30% by weight based on the solid content of the primer resin. A polyolefin molded product coated with a yellowing primer. 4. The polyolefin molded article coated with the non-yellowing primer for an automobile according to claim 1, wherein the primer further contains a polyolefin resin or a chlorinated polyolefin resin.