JPH10279730A - Coated resin product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quality in coated surface appearance of a coated resin product by finely and uniformly dispersing a high content of an adsorbent in a resin molded product. SOLUTION: This coated resin product comprises a resin molded product 4 containing an adsorbent 42, capable of adsorbing a substance formed by modifying a stabilizer 41 and having the surface treated with at least either one of an organosilane coupling agent and a nonionic surfactant in the coated resin product comprising the resin molded product 4 containing the stabilizer 41 and a coating film 5, applied and formed on the surface of the resin molded product 4. The affinity of the adsorbent for the resin is improved and the aggregation in the resin is suppressed by the surface treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated resin product, and more particularly, to a coated resin product capable of preventing discoloration of a coating film over time.

[0002]

2. Description of the Related Art For example, in automobiles, resin parts are frequently used in place of metal for the purpose of improving fuel efficiency by weight reduction. However, a molded resin body is inferior in gloss and color tone to a painted product, so resin parts that do not require special luster, such as registers and accessories, are made into products as molded products, such as bumpers and wheel caps. The most prominent design parts are painted after molding to obtain products.

Design parts such as bumpers and wheel caps generally contain a stabilizer such as an antioxidant or an ultraviolet absorber in a resin molded product or a coating film to improve heat resistance and weather resistance. I have. This stabilizer absorbs radicals generated by heat or light, for example, to prevent the resin from deteriorating.At the time of absorption of radicals, the stabilizer undergoes structural modification such as dimerization, resulting in stabilization. The agent itself may be a coloring substance.

[0004] Further, since a stabilizer is easily dissolved in an organic solvent, when a paint containing an organic solvent is applied to a resin molded product, a part of the stabilizer in the resin molded product may migrate into the coating film. . And when the stabilizer originally contained in the coating film, or the stabilizer transferred from the resin molded body becomes a colored substance,
When the coloring substance is seen through the coating film surface, the coating film may be discolored. Furthermore, the coloring substance itself generated by denaturation of the stabilizer in the resin molded product may migrate into the coating film and discolor the coating film.

[0005] Since the stabilizer and the coloring substance are easily dissolved in the organic solvent, the stabilizer may be contained in the resin regenerated by dissolving the resin molded product in the organic solvent. When a coating resin product is formed by using the above, a phenomenon that the stabilizer is colored with the passage of time and similarly discolors the coating film may occur. Therefore, Japanese Patent Laid-Open No.
No. 7624 discloses a coated resin article in which at least one of a resin molded article and a coating film contains an adsorbent for adsorbing a substance formed by denaturation of a stabilizer.

[0006] In this coated resin product, for example, the radicals generated by heat or light are captured by the stabilizer, so that the resin molded body and the coating film are prevented from deteriorating and discoloration is prevented as in the conventional case. Further, the stabilizer absorbs radicals to cause structural changes such as dimerization, and becomes a colored substance having a larger molecular volume than the stabilizer. However, in the above-mentioned coated resin product, this coloring substance is absorbed into the pores or layers of the adsorbent, so that it is difficult to be desorbed, and is prevented from being transferred to or exposed to the coating film. Discoloration can be prevented.

[0007]

However, the adsorbent disclosed in the above publication is composed of an inorganic substance such as zeolite and activated alumina. For this reason, the dispersibility in the resin is poor, and because it exists as coarse particles agglomerated in the resin molded product, it is not possible to hide the presence of the coarse particles even when applying the coating. There was a disadvantage that the surface appearance was impaired.

[0008] It is difficult to improve the dispersibility of these adsorbent particles only by kneading when molding a resin molded article. It has also been attempted to disperse the adsorbent surface in a resin by treating the adsorbent surface with a dispersant such as a fatty acid, a fatty acid metal salt, or a fatty acid amide. It was difficult to finely disperse.

The present invention has been made in view of such circumstances, and an object of the present invention is to disperse an adsorbent finely and uniformly in a resin molded article, thereby improving the appearance quality of a coated resin product. And

[0010]

A feature of the coated resin article according to the first aspect of the present invention is to provide a resin molded article containing a stabilizer and a coating film formed on the surface of the resin molded article. In a coated resin article comprising: a resin molded article adsorbs a substance formed by denaturation of a stabilizing agent, and is subjected to surface treatment by at least one of an organosilane coupling agent and a nonionic surfactant. Material.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the coated resin article of the present invention, for example, the radicals generated by heat or light are captured by a stabilizer, so that the deterioration of the resin molded product and the coating film is prevented and the discoloration is prevented as in the conventional case. Has been prevented. Further, the stabilizer absorbs radicals to cause structural changes such as dimerization, and becomes a colored substance having a larger molecular volume than the stabilizer. However, in the coated resin article of the present invention, this coloring substance is adsorbed by entering into the pores or layers of the adsorbent as in the prior art, so that it is difficult to be desorbed, and is prevented from being transferred to the coating film or exposed. . Therefore, discoloration of the coating film due to the coloring substance is prevented.

[0012] On the other hand, a stabilizer can also be adsorbed on the adsorbent, but it does not matter for the following two reasons. (1) The proportion of the stabilizer that changes to a colored substance is as small as about 10%, and most of the stabilizer is not adsorbed by the adsorbent, so that the function of the stabilizer hardly decreases. (2) Since the stabilizer has a small molecular volume, even if it is adsorbed by the adsorbent, it is easily desorbed from pores or layers.
The action of the stabilizer for absorbing radicals and preventing the resin from deteriorating is not impaired.

In the coated resin article of the present invention, the adsorbent is surface-treated with at least one of an organosilane coupling agent and a nonionic surfactant. As a result, the affinity with the resin is improved and the agglomeration of the adsorbent in the resin is suppressed, so that the adsorbent is finely and uniformly dispersed in the resin molded body, and the surface smoothness of the resin molded body itself is improved and the coating is performed. The surface appearance quality is significantly improved.

As the adsorbent, those having, for example, pores or a layered structure and adsorbing by retaining a coloring substance or the like in which a stabilizer is denatured between the pores or layers are used. Sepiolite (trade name) ), Kanemite (trade name) and the like, or activated clay, silica gel, diatomaceous earth, activated alumina and the like. The coloring substance or the like in which the stabilizer is modified has a larger molecular volume than the stabilizer due to dimerization or the like, and is adsorbed through the pores or layers. Therefore, the pore diameter or the interlayer distance of the adsorbent is more preferably in the range of 10 to 100 ° which is easy to hold a coloring substance or the like and is difficult to be detached.
Å It is desirable to be near. In this range, the coloring substance or the like in which the stabilizer is denatured is hardly desorbed after being adsorbed, so that the discoloration is more reliably prevented. If this value is smaller than 10 °, it becomes difficult to adsorb colored substances and the like, and 100 °
If it is larger, desorption becomes easier even if adsorbed,
Coloring of the coating film occurs.

On the other hand, since the molecular volume of the stabilizer itself is less than half of that of the coloring material, etc., if the pore diameter or the interlayer distance of the adsorbent is 10 ° or more, it can be easily desorbed even if adsorbed. The action of the stabilizer is maintained. Further, the addition amount of the adsorbent is more preferably about 1 to 10% by weight of the resin molded body. If the amount is too small, the effect of preventing discoloration hardly appears, and if the amount is too large, the physical properties of the resin molded product and the physical properties of the coating film may be deteriorated.

The organosilane coupling agent includes:
A silane coupling agent having an epoxy group, a methacryloxy group or a mercapto group is exemplified. By the surface treatment with the organosilane coupling agent, the surface of the adsorbent particles is improved in the bonding strength with the resin and the aggregation is suppressed, so that the dispersibility is improved. It is desirable that the organosilane coupling agent be used in a range of 0.1 to 10% by weight in the resin molded product. When the amount of the organosilane coupling agent is less than 0.1% by weight, it is difficult to uniformly disperse the adsorbent, and the appearance quality of the coating surface is deteriorated due to aggregation.
If the content is more than 10% by weight, the effect is saturated, and the physical properties of the resin molded article may be undesirably reduced.

Examples of the nonionic surfactant include succinimide, N-polyoxyalkylene polyalkylene polyamine, and polyacrylamide derivative. By being surface-treated with this nonionic surfactant, the surface of the adsorbent particles becomes lipophilic, so that the affinity with the resin is improved, and the adsorbent particles repel each other, suppressing aggregation and suppressing dispersion. The performance is improved.

The nonionic surfactant is desirably used in an amount of 0.1 to 10% by weight in the resin molded product. If the amount of the nonionic surfactant is less than 0.1% by weight, it becomes difficult to uniformly disperse the adsorbent, and the appearance quality of the painted surface deteriorates due to aggregation. If the content is more than 10% by weight, the effect is saturated, and the physical properties of the resin molded article may be undesirably reduced.

The organosilane coupling agent and the nonionic surfactant may be used alone or in combination. If you use both,
After one of the adsorbents is subjected to the surface treatment, the other may be subjected to the surface treatment, or both may be subjected to the surface treatment at the same time. As a surface treatment method, a known disperser such as a jet mill, a colloid mill, a sand mill, a ball mill, and a Henschel mixer is used to mix an adsorbent with an organosilane coupling agent and / or a nonionic surfactant. It can be carried out.

[0020]

The present invention will be more specifically described below with reference to examples and comparative examples. (Embodiment 1) FIG. 1 is a sectional view of a main part of a coated resin article of the present embodiment. This coating resin product is equivalent to a bumper of an automobile, and has a filler 40 made of talc, EPR, and carbon black containing polypropylene (PP) as a main component of a matrix, an antioxidant 41 as a stabilizer, and an organosilane cup. It is composed of a resin molded body 4 containing a treated zeolite 42 surface-treated with a ring agent, and a coating film 5 coated on the surface of the resin molded body 4.

Hereinafter, the method for producing the coated resin article will be described, and the detailed description of the structure will be replaced. First, 100 g of zeolite ("Kanemite", manufactured by Omi Kogyo Co., Ltd.) and 350 g of ethyl alcohol were wet-mixed with a sand mill and pulverized, so that the zeolite had an average particle diameter of 4 µm. The particle diameter was measured as an aqueous dispersion using "Horiba LA-700".

Next, 1.0 g of γ-methacryloxypropylmethyldiethoxysilane was dissolved in ethyl alcohol and added to the slurry, followed by stirring with a Henschel mixer, and then evaporating the ethyl alcohol using a rotary evaporator. It was made to dry and further pulverized with a ball mill to prepare a treated zeolite powder. Then, based on the polypropylene (PP) powder, 1% by weight of an antioxidant ("BHT" manufactured by Yoshitomi Pharmaceutical Co., Ltd.) as a stabilizer, 38% by weight of a filler such as talc, and the above treatment as an adsorbent 1% by weight of zeolite powder was added, mixed, extruded and then pelletized to obtain molded pellets.

A plate-like test plate was formed from the molded pellet by injection molding. Then, on one side of this test plate, a chlorinated polyolefin-based primer was applied in a thickness of 5 μm, an alkyd / melamine-based intermediate coating material having a thickness of 30 μm, and an acrylic / melamine-based white top coating material having a thickness of 45 μm in this order. Test pieces were prepared. (Example 2) A treated zeolite powder was prepared in the same manner as in Example 1, except that 1.0 g of γ-mercaptopropyltrimethoxysilane was used instead of γ-methacryloxypropylmethyldiethoxysilane. Test pieces were prepared.

Example 3 1.0 g of β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane was used instead of γ-methacryloxypropylmethyldiethoxysilane.
Except for using, a treated zeolite powder was prepared in the same manner as in Example 1, and a test piece was prepared in the same manner.

Example 4 The procedure of Example 1 was repeated except that 1.0 g of N-polyoxyalkylene polyalkylene polyamine, which was a nonionic surfactant, was used in place of γ-methacryloxypropylmethyldiethoxysilane. Thus, a treated zeolite powder was prepared, and a test piece was prepared in the same manner.

Example 5 A treated zeolite powder was prepared in the same manner as in Example 1 except that succinimide, a nonionic surfactant, was used in an amount of 1.0 g instead of γ-methacryloxypropylmethyldiethoxysilane. It was prepared and a test piece was prepared in the same manner. Example 6 A treated zeolite powder was prepared in the same manner as in Example 1, except that 1.0 g of a polyacrylamide derivative as a nonionic surfactant was used in place of γ-methacryloxypropylmethyldiethoxysilane. Then, a test piece was prepared in the same manner.

Example 7 First, 100 g of zeolite (“Kanemite” manufactured by Omi Kogyo Co., Ltd.) and ethyl alcohol 3
50 g of the zeolite was wet-mixed with a sand mill and pulverized to make the average particle diameter of the zeolite 4 μm. The measurement of the average particle diameter was performed in the same manner as in Example 1. Next, for this slurry,
After dissolving 1.0 g of γ-methacryloxypropylmethyldiethoxysilane and 0.2 g of N-polyoxyalkylene polyalkylene polyamine in ethyl alcohol and adding the resulting mixture, and stirring with a Henschel mixer, the mixture was mixed with ethyl alcohol using a rotary evaporator. Evaporate the alcohol to dryness,
The powder was further pulverized by a ball mill to prepare a treated zeolite powder.

A molded pellet was prepared in the same manner as in Example 1 except that this treated zeolite powder was used, and a test piece was prepared in the same manner. (Example 8) First, 100 g of zeolite ("Kanemite", manufactured by Omi Kogyo Co., Ltd.) and 350 g of ethyl alcohol were wet-mixed with a sand mill and pulverized, so that the zeolite had an average particle diameter of 4 µm. The measurement of the average particle diameter was performed in the same manner as in Example 1.

Next, 1.0 g of γ-mercaptopropyltrimethoxysilane and 0.2 g of N-polyoxyalkylene polyalkylene polyamine dissolved in ethyl alcohol were added to the slurry, and the mixture was stirred with a Henschel mixer. After that, the ethyl alcohol was evaporated to dryness using a rotary evaporator, and further pulverized with a ball mill to prepare a treated zeolite powder.

Then, a molded pellet was prepared in the same manner as in Example 1 except that this treated zeolite powder was used, and a test piece was prepared in the same manner. Comparative Example 1 A molded pellet was prepared in the same manner as in Example 1 except that zeolite having an average particle size of 20 μm or more (“Kanemite” manufactured by Omi Kogyo Co., Ltd.) was used as it was, and a test piece was prepared in the same manner. did.

Comparative Example 2 First, 100 g of zeolite (“Kanemite” manufactured by Omi Kogyo Co., Ltd.) and ethyl alcohol 3
50 g of the zeolite was wet-mixed with a sand mill and pulverized to make the average particle diameter of the zeolite 4 μm. The measurement of the average particle diameter was performed in the same manner as in Example 1. Next, ethyl alcohol was evaporated to dryness using a rotary evaporator, and further pulverized with a ball mill to prepare an untreated zeolite powder.

A molded pellet was prepared in the same manner as in Example 1 except that this untreated zeolite powder was used, and a test piece was prepared in the same manner. (Comparative Example 3) 1.0 g of sodium stearate instead of γ-methacryloxypropylmethyldiethoxysilane
Except for using, a treated zeolite powder was prepared in the same manner as in Example 1, and a test piece was prepared in the same manner.

Comparative Example 4 A treated zeolite powder was prepared and tested in the same manner as in Example 1 except that 1.0 g of potassium stearate was used instead of γ-methacryloxypropylmethyldiethoxysilane. Pieces were made. (Comparative Example 5) 1.0 g of calcium stearate was used instead of γ-methacryloxypropylmethyldiethoxysilane.
Except for using, a treated zeolite powder was prepared in the same manner as in Example 1, and a test piece was prepared in the same manner.

Comparative Example 6 A treated zeolite powder was prepared in the same manner as in Example 1 except that 1.0 g of sodium dioctylsulfosuccinate was used instead of γ-methacryloxypropylmethyldiethoxysilane. Test pieces were prepared. (Comparative Example 7) A treated zeolite powder was prepared in the same manner as in Example 1 except that 1.0 g of polyethylene glycol alkylamine was used instead of γ-methacryloxypropylmethyldiethoxysilane, and a test piece was prepared in the same manner. Produced.

Comparative Example 8 An antioxidant ("BHT" manufactured by Yoshitomi Pharmaceutical Co., Ltd.) as a stabilizer was added at 1% by weight to polypropylene (PP) powder without using an adsorbent, and talc or the like was used. 38% by weight of the filler was mixed, extruded, and pelletized to obtain molded pellets. A test piece was prepared in the same manner as in Example 1 except that this molded pellet was used.

(Test / Evaluation) The smoothness of each of the obtained test pieces was measured using an ultra-small surface roughness measuring instrument (“Handy Surf E-30A” manufactured by Tokyo Seimitsu Co., Ltd.). It is shown in Table 1. In Table 1, ◎ indicates a surface roughness of less than 0.10 μm, ○ indicates a surface roughness of 0.1 μm or more and less than 0.3 μm, and X indicates a surface roughness of 0.30 or more.

Each test piece was subjected to a heat resistance test of heating at 80 ° C. for 480 hours. Then, using a “SM Color Computer 5S-1S-2B” (manufactured by Suga Test Instruments Co., Ltd.), the reflection spectrum of the painted surface before and after the heat resistance test was measured at several points, and the average value of the difference between the b values calculated therefrom was measured. (Δb value)
Was determined as the degree of yellowing. Note that this Δb value is based on JISZ8
730-1980 (CIE-19
76b). Table 1 shows the results.
In addition, the display of the Δb value in Table 1 indicates a distribution of a plurality of measurement results performed on a plurality of test pieces in each example.

[0038]

[Table 1] From Table 1, it can be seen that the use of a zeolite treated with an organosilane coupling agent or a nonionic surfactant significantly improves the surface smoothness of a coated resin product while maintaining a high yellowing suppression ability. Recognize. It is also clear that the combined use of an organosilane coupling agent and a nonionic surfactant further improves the surface smoothness.

The test pieces of Examples 7 and 8 and the test pieces of Comparative Examples 1 and 8 whose surface smoothness was remarkably improved and the sharpness of the resin molded product itself before coating were measured. The gloss was measured and the results are shown in Table 2. The sharpness is measured using a sharpness gloss meter (“PGD-IV” manufactured by Tokyo Koden Co., Ltd.), and the glossiness is measured using a micro-TRI GLOSS (“cat No.4520” BYK-
Gardner GmbH) was used to measure the 60 ° specular reflectance.

[0040]

[Table 2] From Table 2, in Comparative Example 1, the particle size of the adsorbent was large,
Low sharpness and low gloss. Further, in Comparative Example 8, since the resin slippage and the releasability from the mold were poor, the sharpness and glossiness were low even though no adsorbent was contained.

However, although the test pieces of Examples 7 and 8 contained an adsorbent, they exhibited extremely high sharpness and glossiness even in comparison with Comparative Example 8, and the adsorbent was formed of resin. It is evident that it is very finely distributed evenly throughout the body.

[0042]

According to the coating resin product of the present invention,
Since the adsorbent does not agglomerate and is uniformly and highly dispersed in the resin molded article, the smoothness of the resin molded article itself is remarkably improved, and the appearance quality of the painted surface is remarkably improved. And even if the stabilizer itself is colored, the transition to the coating film is prevented by being adsorbed by the adsorbent, and the appearance of the color is prevented,
Discoloration of the coating film can be prevented for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a coated resin article according to one embodiment of the present invention. 4: Resin molded body 5: Coating film 40:
Filler 41: Antioxidant (stabilizer) 42: Treated zeolite (adsorbent)

Claims (1)

[Claims] 1. A coated resin article comprising a resin molded product containing a stabilizer and a coating film formed on the surface of the resin molded product, wherein the resin molded product is obtained by denaturing the stabilizer. A coated resin article, characterized by containing an adsorbent which adsorbs a substance formed by the above-mentioned method and which has been subjected to a surface treatment of at least one of an organosilane coupling agent and a nonionic surfactant.