JP2001009369A - Exterior panel for car and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an exterior panel molded product for a car excellent in mechanical strength such as rigidity or the like and having no orange peel or the like on its coating surface. SOLUTION: A hollow exterior panel molded product 1 for a car is produced by blow molding and a coating film is applied to the outer surface thereof. In the blow molding of the exterior panel molded product for a car, molds having fine unevenness showing a surface roughness of 3-13.5 μm are used and a parison 3 comprising crystalline resin having the flexural modulus of elasticity of 9,000 kg/cm2 or more at 23 deg.C is arranged between the molds and the surface temp. of the cavities 4a, 5a of the molds is set to a range satisfying A<Y<1.07B [wherein A is a crystallization peak temp. ( deg.C) in a DSC curve of the crystalline resin with the flexural modulus of elasticity of 9,000 kg/cm2 or more at 23 deg.C and B is a fusion peak temp. ( deg.C) in the DSC curve of the crystalline resin with the flexural modulus of elasticity of 9,000 kg/cm2 or more at 23 deg.C]. The thickness of the coating film is set to 120 μm or less and the surface roughness H of the molded product and the thickness T of the coating film have a relation of T (μm)>=4.5 (μm)+10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automotive exterior panel having a good appearance and a method for producing the same.

[0002]

2. Description of the Related Art A conventional method for producing a hollow molded article having a good appearance will be described. (B) A split mold having a mirror-finished cavity surface is used, and the opened mold has a tensile modulus of 20.
A parison made of an amorphous resin having a temperature of 00 Kg / cm ² of 75 ° C. or more is placed, the mold is closed, and then, when a gas is blown into the parison and brought into close contact with the cavity, the cavity temperature Y ′ ° C. At a temperature X ′ ° C. at which the tensile modulus of the amorphous resin becomes 2000 kg / cm ^2.
(2) Thermoplastic resin (Y) = (0.96X'-37)-(0.96X '+ 3) In thermoforming or hollow molding of
A method for improving the glossiness of the surface of a molded article by selectively and instantaneously heating and molding the surface of the mold to a temperature higher than the thermal deformation temperature of the resin by high-frequency induction heating (Japanese Patent Publication No.
No. 27849). (C) It is made of crystalline resin and has a depth of 2 to 100 μm on the surface.
Blow molding a molten parison having a large number of fine irregularities formed in a mirror-finished mold with a roughness of 0.5 S or less heated to a temperature higher than the crystallization temperature of the resin (Japanese Patent Publication No. No. 40498).

[0003]

Among the prior arts described above, (a) is inevitable that spots and linear marks are formed on the outer surface of the amorphous resin hollow molded article, resulting in poor appearance. When manufacturing automotive exterior panels that are strictly required, the outer surface of the blow molded amorphous resin hollow molded product is polished or water-polished to remove spots and linear marks, etc. A coating must be applied. For this reason, there has been a problem that the number of steps is increased and the manufacturing cost is increased.

[0004] In addition, (b) has a problem that the cost is increased because it is necessary to provide a special molding device having a heating device for high-frequency induction heating of the mold.

Further, (c) shows that the surface of the parison has a depth of 2.
Although melt fracture is generated in the parison to form a large number of fine irregularities of about 100 μm, there is a problem that the melt fracture is difficult to control and is not suitable for mass production.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been made in consideration of the above-mentioned problems. The object of the present invention is to provide an automotive exterior panel and a method for producing the same, which can provide an automobile exterior panel having excellent mechanical strength such as rigidity and a good appearance without having peeled skin on a painted surface simply by applying a coating. Is what you do.

[0007]

According to a first aspect of the present invention, there is provided an automotive exterior panel having a tensile modulus of 20.
00Kg / cm ² and comprising temperature flexural modulus in the non-crystalline resin or 23 ° C. over 75 ° C. is 9000 kg / cm
The surface roughness of a molded product of a hollow automotive exterior plate obtained by applying a coating having a thickness of 120 μm or less to the outer surface of a hollow automotive exterior plate molded product obtained by blow molding ^two or more crystalline resins is 3 μm or less.
１３13.5 μm, and the surface roughness (H) of the molded product
And the film thickness (T) of the coating film has a relationship represented by the following equation. T ≧ 4.5H + 10

Further, the tensile modulus of elasticity is 2000 kg / cm ²
The amorphous resin having a temperature of 75 ° C. or higher or the crystalline resin having a flexural modulus at 23 ° C. of 9000 Kg / cm ² or higher may be blended with an inorganic filler in the range of 3 to 35% by weight.

Further, the first method for producing an automotive exterior panel according to the present invention comprises the steps of: forming a hollow automobile exterior panel by blow molding; and applying a coating film on an outer surface of the automotive exterior panel molded product. In the manufacturing method, the blow molding of the automotive exterior plate molded product has a surface roughness of 3 to 13.5 μm.
And a tensile elastic modulus of 2000 Kg / cm ² between the opened molds.
After a parison made of an amorphous resin having a temperature of 75 ° C. or more is arranged, the mold is closed, and then a pressurized fluid is introduced into the parison to adhere to the cavity, and the surface temperature of the cavity Y ° C. Tensile modulus of amorphous resin is 2
At a temperature X ° C. of 000 Kg / cm ² , Y is set within the range of (0.96X + 3) to (0.96X + 40), and the film thickness of the applied coating is set to within 120 μm or less. The following formula is satisfied between the surface roughness (H) of the molded article and the film thickness (T) of the coating film. T ≧ 4.5H + 10

[0010] The second method for manufacturing an automobile exterior panel according to the present invention comprises the step of blow-molding a hollow automobile exterior panel and then applying a coating film on an outer surface of the automobile exterior panel molded article. The blow molding of the molded article for an automotive exterior plate has a surface roughness of 3 to 13.5 μm.
A mold having minute irregularities within the range of is used, and a flexural modulus at 23 ° C. between the opened molds is 900.
After disposing a parison made of a crystalline resin of 0 kg / cm ² or more, the mold is closed, and then a pressurized fluid is introduced into the parison to adhere to the cavity, and the surface temperature y ° C. of the cavity is represented by the following formula: A <A < y <1.07B where A: flexural modulus at 23 ° C. is 9000 kg
/ Cm ² or more crystallization peak temperature in the DSC curve of the crystalline resin (° C.) B: bending elastic modulus at 23 ° C. is 9000 kg / cm ²
The surface roughness (H) of the molded product and the film thickness of the coating film are set within the range of satisfying the melting peak temperature (° C.) in the DSC curve of the above crystalline resin, and the thickness of the coating film to be applied is within the range of 120 μm or less. It is characterized by satisfying the following expression with the film thickness (T). T ≧ 4.5H + 10

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the prior art described above, spots and linear marks on the outer surface of a blow-molded resin hollow molded product are caused by rough skin, die lines, and bumps on the outer surface of a parison. It is. The rough surface is caused by the flow of the molten resin passing through the extrusion head when the parison is extruded, and is irregular irregularities of about 2 μm or more generated on the outer surface of the parison. The die line is
This is caused by a joint in the flow direction of the molten resin in the head when the parison is extruded, and is a streak-like depression of 2 to 500 μm generated on the outer surface of the parison. Butts are caused by unmelted particles or carbides of the resin, and are protrusions or recesses of 5 to 1000 μm appearing on the outer surface of the parison.

Therefore, as a result of repeating many experiments, the rough surface generated on the outer surface of the parison, the spots and linear marks generated on the surface of the resin molded product due to the die line and the bumps are found in the mold having the mirror surface cavity. Rather than using a mold having a surface with minute irregularities of a predetermined surface roughness in a cavity, the surface temperature of the cavity is set to a predetermined temperature and blow molded, and the surface roughness of the minute irregularities of the cavity is It has been found that it can be suppressed by applying a coating film having a predetermined thickness corresponding to the above.

The above findings were surprising from the conventional common sense. This finding is more important than the following two points. One of them is that the surface roughness of the parison, spots and linear marks generated on the outer surface of the resin molded product due to die lines and bumps can be removed by raising the surface temperature of the cavity to a predetermined temperature. It turns out. By raising the surface of the parison to a predetermined temperature, spots and linear marks formed on the surface of the parison during extrusion can be eliminated. This is as if the parison was given a kind of heat treatment depending on the surface temperature of the cavity. This makes it possible to remove spots, linear marks, and the like that could not be removed by the conventional technology.

However, in the case of a resin molded article, when the surface temperature of the cavity is raised to a predetermined temperature, rough skin generated on the surface of the parison, spots and linear marks generated by die lines and bumps can be removed. It has been found that a crater-like material called an air mark is newly generated on the surface of such a treatment. If this air mark is applied as it is, the air mark will be reflected on the painted surface, so in the end the painting must be removed by polishing or water sharpening as before. Would. It has also been found that the more complicated the shape of the resin molded product, the more the air mark tends to be generated in the complicated shape.

Therefore, it is another finding that the surface roughness of the fine irregularities of the cavity is set within a range of 3 to 13.5 μm, and the film is formed within a predetermined range corresponding to the surface roughness of the fine irregularities of the cavity. That is, it can be suppressed by applying a thick coating film. When the surface of the resin molded article is coated with specific minute irregularities, the coating film enters the inside of the minute irregularities by a kind of capillary phenomenon, and as a result, a good painted surface is obtained.

According to the present invention, as described above, the rough surface generated on the outer surface of the parison, spots and linear marks generated on the outer surface of the resin molded product due to die lines and bumps can be eliminated by using a mold having a mirror-surface cavity. Rather, using a mold having minute irregularities with a predetermined surface roughness in the cavity, the surface temperature of the cavity is set to a predetermined temperature, and blow molding is performed to correspond to the surface roughness of the minute irregularities in the cavity. It has been found that it can be suppressed by applying a coating film having a predetermined thickness.

Judging from these facts, the tensile modulus was 20%.
00Kg / cm ² and comprising temperature flexural modulus in the non-crystalline resin or 23 ° C. over 75 ° C. is 9000 kg / cm
An automotive exterior panel obtained by applying a coating having a thickness of 120 μm or less to the outer surface of a hollow automotive exterior panel molded article obtained by blow molding ^two or more crystalline resins has a surface roughness of 3 to 13.
If the relationship between the surface roughness (H) of the molded article and the film thickness (T) of the coating film satisfies the relation represented by a specific formula, the painted surface of the surface is not citrus. It has been found that a beautiful appearance free from the like and the like can be obtained, and that the material has mechanical strength such as rigidity required for an exterior panel for an automobile.

Also, the tensile modulus is 2000 kg / cm ^2.
Amorphous resin having a temperature of 75 ° C. or more or crystalline resin having a flexural modulus at 23 ° C. of 9000 Kg / cm ² or more is blended with an inorganic filler within a range of 3 to 35% by weight to blow. The parting line generated in the molded automobile exterior plate molded product is easily removed by ordinary processing such as sanding. If the blending ratio of the inorganic filler is less than 3% by weight, scorching or the like will occur during the operation of removing the parting line by sanding or the like, and it will not be possible to finish to a predetermined surface roughness. Conversely, if the blending ratio of the inorganic filler is more than 35% by weight, it becomes too hard, resulting in a decrease in the skin on the painted surface, a decrease in the moldability, and a decrease in the physical properties of the product.

Next, a first embodiment of the method for manufacturing an automotive exterior panel according to the present invention will be described. As shown in FIG. 1, the divided molds 4 and 5 having minute unevenness having the surface roughness of the cavities 4 a and 5 a within the range of 3 to 13.5 μm are used. The temperature at which the tensile modulus becomes 2000 kg / cm ² is 7
A parison 3 made of an amorphous resin at 5 ° C. or higher is extruded from the extrusion head 2 and arranged. After the above, the molds 4 and 5 are closed, the parison 3 is clamped, and then the parison 3 is blown with a blowing needle (not shown).
A pressurized air of about 7 kg / cm ² , which is a pressurized fluid, is introduced into the inside and expanded to bring it into close contact with the cavities 4 a and 5 a to blow-mold the hollow automobile molded plate molded article 1.

In this step, the parison 3 is brought into contact with the cavities 4a, 5a immediately before or after the heating by the heating means 6, 7 using a heating medium such as heating water, steam, oil or the like provided in the dies 4, 5. When the surface temperature of the cavities 4a and 5a is Y ° C., the tensile elastic modulus of the amorphous resin is 2000 kg.
/ Cm ² , Y = (0.96X +
It is important to set it within the range of 3) to (0.96X + 40).

After the above steps, the molded product 1 is cooled in the molds 4 and 5, and then the mold is opened and taken out as shown in FIG. 2 to remove excess burrs. After the above process, a coating film having a thickness of 120 μm or less is applied to the outer surface of the molded article 1 for an automobile exterior plate to produce an exterior panel for an automobile.

The tensile modulus in the present invention is defined by JISK
Test speed 2m using No. 2 type test piece according to 7113
It shows the value tested in m / min. Even the same type of amorphous resin shows different values depending on the characteristics of each resin. An amorphous resin having a tensile modulus of 2000 kg / cm ² at a temperature of 75 ° C. or higher, and more preferably 85 ° C. or higher has excellent heat resistance. For example, a modified polyphenyl oxide resin, a polycarbonate resin, an amorphous polyamide resin, an ABS resin, and a polysulfone resin. As a blend (alloy) resin of an amorphous resin, a blend (alloy) resin of an ABS resin and a polycarbonate resin is preferable.

The amorphous resin in the present invention is a blend (alloy) resin having an amorphous resin component of 30% by weight or more and an amorphous resin and a crystalline resin, and having a tensile modulus of 2000 kg. It may be a resin having a temperature of not less than 75 ° C./cm ² . For example, as a blended (alloy) resin of an amorphous resin and a crystalline resin, a blended (alloy) resin of a modified polyphenylene oxide resin and a polyamide resin,
It is a blend (alloy) resin of a polycarbonate resin and a polybutylene terephthalate resin.

Next, a description will be given of a second embodiment of the method for manufacturing an automotive exterior panel according to the present invention. As shown in FIG. 1, the divided molds 4 and 5 having minute unevenness having the surface roughness of the cavities 4 a and 5 a within the range of 3 to 13.5 μm are used. Then, a parison 3 made of a crystalline resin having a flexural modulus of 9000 Kg / cm ² or more is extruded from the extrusion head 2 and arranged. After the above, the molds 4 and 5 are closed, the parison 3 is clamped, and then the parison 3 is blown with a blowing needle (not shown).
A pressurized air of about 7 kg / cm ² , which is a pressurized fluid, is introduced into the inside and expanded to bring it into close contact with the cavities 4 a and 5 a to blow-mold the hollow automobile molded plate molded article 1.

In the present step, the parison 3 is brought into contact with the cavities 4a, 5a immediately before or after the cavities 4a, 5a are brought into close contact with the cavities 4a, 5a by heating means 6, 7 using a heating medium such as heating water, steam, oil or the like provided in the dies 4, 5. The surface temperature y ° C. of the cavities 4a and 5a is expressed by the following equation: A <y <1.07B where A: the flexural modulus at 23 ° C. is 9000 kg.
/ Cm ² or more of a crystalline resin having a DSC curve (JISK71
21) B: The flexural modulus at 23 ° C. is 9000 Kg / cm ^2.
The temperature is raised so as to satisfy the melting peak temperature (° C.) in the DSC curve (see JIS K7121) of the above crystalline resin.

After the above steps, the molded product 1 is cooled in the dies 4 and 5, and then the mold is opened and taken out as shown in FIG. 2 to remove excess burrs. After the above steps, a coating film is applied to the outer surface of the molded article 1 for an automotive exterior plate to produce an exterior panel for an automobile.

The flexural modulus at 23 ° C. in the present invention is as shown in JIS K7171. A crystalline resin having a flexural modulus at 23 ° C. of 9000 Kg / cm ² or more satisfies mechanical strength such as rigidity required for an automotive exterior panel, and includes, for example, a polypropylene resin, a high-density polyethylene resin, and a polyamide. Resin (for example, nylon 6), polybutylene terephthalate resin,
A simple resin such as a polyethylene terephthalate resin, a blend (alloy) resin with an amorphous resin containing at least 30% by weight of a crystalline resin thereof, and a blend (alloy) resin of these crystalline resins. .
Examples of the blend (alloy) resin with the amorphous resin include polyamide resin / modified polyphenylene ether resin or polypropylene resin / polystyrene resin. As a blend (alloy) resin of crystalline resins, polypropylene resin / high-density polyethylene resin may be used.

The crystallization peak temperature in the present invention is defined as J
It is the crystallization peak temperature in the DSC curve defined by ISK7121, and the same as the melting peak temperature according to JISK.
7 is a melting peak temperature in a DSC curve defined in 7121. Here, a blend with an amorphous resin (alloy)
In the case of a resin, the crystallization peak temperature and the melting peak temperature of the crystalline resin contained therein are the respective temperatures of the blend (alloy) resin. In addition, in the case of a blended (alloy) resin of crystalline resins, the temperature obtained from the arithmetic average of the respective temperatures of the respective crystalline resins contained therein according to their blending ratio can be treated as the current temperature. found.

For example, the blending ratio of the crystalline resin (a) is a%, the melting peak temperature is t ₁ , and the melting peak temperature of the crystalline resin (b) is t _2. The temperature B is as follows: B = (a / 100) t ₁ + (1−b / 100) t ₂ However, the melting peak temperatures of these two types of crystalline resins (a) and (b) are close to each other, and
If the peak of the curve did not appear clearly, the peak of the peak of the DSC curve was taken as the melting peak temperature of the blend. Similarly, the crystallization peak temperature can be determined by the above method.

Table 1 shows the temperatures of typical crystalline resins used in the present invention.

[Table 1]

The surface roughness of the rough surface formed on the outer surface of the molded article of the automotive exterior plate shall be within the range of 3 to 13.5 μm. Roughness based on the maximum height measured by a measuring instrument (JI
SB0601), which is specifically obtained from the sum of the maximum height of the peaks (convex) and the maximum depth of the valleys (concave) of the rough surface or minute unevenness. The rough surface roughness, especially in the case of blow-molded article, the surface of the crest is determined from the maximum height R _max (JISB0601) rather than the roughness curve by a profile curve since it is often a gradual curve (JISB0601) ( The maximum value of the convex (convex) and the maximum depth of the valley (concave) were used. At this time, the roughness curve cutoff value was 0.8 mm. In order to form minute irregularities having a surface roughness within the range of 3 to 13.5 μm in the cavity, it is preferable to spray sand having a grain size of # 120 to # 800, that is, sand blast.

Further, the coating of the coating film on the outer surface of the molded article of the automotive exterior plate is performed by spraying the coating with an air spray in the same manner as a known coating method to form a coating film of 120 μm or less. In the present invention, the exterior panel for automobiles is strictly required to have a so-called good appearance with clear surface gloss and color tone. Spoiler, bumper, trunk lid, side molding, fender, hood, etc.

[0033]

EXAMPLE As an experimental example, a blow molding machine equipped with an extruder having a screw diameter of 90 mm was used, as shown in FIG.
Length L is 1200 mm, width D is 180 mm, height H is 9
Spoiler molded product 1 having a thickness of 0 mm and an average thickness of 3 mm
After blow molding No. 0, a spoiler in which a coating film was applied to the outer surface of a spoiler molded product was manufactured.

Table 2 shows Experimental Examples 1 to 7.

[Table 2]

In Experimental Examples 1 to 7, the surface roughness of the cavities was 3 μm and 5 μm, respectively, by sandblasting.
μm, 9 μm, 10 μm, 11.5 μm, 13.5 μ
m, 18 μm and an ABS resin (YM254, manufactured by Techno Polymer Co., X = 105)
C) was extruded at 240 ° C., and a coating having the film thickness shown in Table 2 was applied to the spoiler molded body obtained at a heating temperature of 125 ° C. on the surface of the cavity to obtain each sample.
The surface roughness shown in Table 2 indicates the surface roughness of the molded spoiler. FIG. 4 is a graph of the results shown in Table 2.

From Table 2, it can be seen that the surface of the spoiler molded body heated to 125 ° C. has the same surface roughness as the surface roughness of the mold cavity. Also, from Table 2 and FIG. 4, it can be seen that a good coating surface can be obtained within the range indicated by the wavy line. The inclined wavy line is T = 4.5H
It is indicated by +10. The wavy line indicated by T = 120 indicates that when the coating film exceeds 120 μm, the practical use is economically reduced.

Table 3 shows Experimental Example 8. Experimental Example 8 was performed using a mold having a surface roughness of 9 μm, changing the surface temperature of the cavity to form a spoiler molded product, and manufacturing a spoiler having a 58 μm coating film applied to the outer surface of the spoiler. Was obtained in the same manner as in Example 3.

[Table 3]

According to Table 3, the surface roughness of the cavity of the mold is 9
When the heating temperature is lower than μm, a value larger than the surface roughness of the mold cavity appears. It is expected that this is because the unevenness generated on the surface during the extrusion of the parison remains without involving the surface of the molded product. It can be seen that when the heating temperature exceeds 105 ° C., the irregularities generated on the surface of the parison can be removed by the heat treatment. It can be seen that when the surface roughness is 13.5 μm or more, a film thickness of 58 μm cannot cope with it, and the irregularities appear on the painted surface to deteriorate the appearance.

Table 4 shows Experimental Examples 9 to 15.

[Table 4]

In Experimental Examples 9 to 15, the surface roughness of the cavities was 3 μm each by sandblasting.
5 μm, 9 μm, 10 μm, 11.5 μm, 13.5 μ
m and 18 μm, a parison of a blend of polypropylene resin / high-density polyethylene resin was extruded at 210 ° C., and a heating temperature of the cavity surface was adjusted to 125 ° C. to form a spoiler molded body. Was applied to obtain samples. Here, the polypropylene / high-density polyethylene resin is polypropylene (manufactured by Nippon Polychem Co., Ltd., EC9, A = 115 ° C.,
B = 162 ° C.) and high-density polyethylene (B970, A = 121 ° C., B = 130 ° C., manufactured by Asahi Chemical Industry Co., Ltd.) at a ratio of 70:30. , A = 116.8 ° C, B = 1
52.4 ° C. The surface roughness shown in Table 4 indicates the surface roughness of the molded spoiler.

From Table 4, it can be seen that the surface of the spoiler molded body heated to 125 ° C. has the same surface roughness as the surface roughness of the mold cavity. When the surface roughness of the spoiler molded body is 3 μm, there is a problem in appearance when the thickness of the painted surface is 15 μm or less, and when the surface roughness of the spoiler molded body is 5 μm, the appearance is reduced when the thickness of the painted surface is 30 μm or less. There's a problem. It can be seen that as the surface roughness of the spoiler formed body increases, a good appearance cannot be obtained unless the thickness of the painted surface is increased. When the surface roughness of the spoiler molded body exceeds 13.5 μm, it can be seen that the appearance defect cannot be eliminated even if the thickness of the painted surface is large.

Experimental Example 16 is shown in Table 5.

[Table 5]

In Experimental Example 16, a mold having a surface roughness of 9 μm was used to form a spoiler molded article by changing the surface temperature of the cavity.
It was obtained in the same manner as in Example 11 except that a spoiler coated with a 0 μm coating was manufactured.

According to Table 5, the surface roughness of the mold cavity is 9 μm.
If the heating temperature is lower than m, a value larger than the surface roughness of the mold cavity appears. It is expected that this is because the unevenness generated on the surface during the extrusion of the parison remains without involving the surface of the molded product. It can be seen that when the heating temperature exceeds 120 ° C., the irregularities generated on the surface of the parison can be removed by the heat treatment. It can be seen that when the surface roughness is 13.5 μm or more, a film thickness of 60 μm cannot cope with the roughness, and the irregularities appear on the painted surface to deteriorate the appearance.

[0045]

According to the present invention, a blow-molded automotive exterior plate is excellent in mechanical strength such as rigidity by merely applying a coating film without polishing or water-sharpening the outer surface. In addition, it is possible to obtain an exterior panel for an automobile having a good appearance without a yuzu skin on a painted surface.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a blow molding mode of an automotive exterior panel according to the present invention, showing a state in which a parison is extruded between open molds.

FIG. 2 is a cross-sectional view illustrating a state in which a blow-molded automotive exterior plate molded product is cooled in a mold and then the mold is opened.

FIG. 3 is a perspective view showing a blow molded spoiler product.

FIG. 4 is a graph showing the results of Experimental Examples 1 to 7 shown in Table 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automotive exterior plate molded product 2 Extrusion head 3 Parison 4,5 Die 4a, 5a Cavity 6,7 Heating means 10 Spoiler molded product

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29C 49/78 B29C 49/78 B32B 27/20 B32B 27/20 Z // B29K 105: 16 B29L 31:30 F-term (reference) 4D075 AE03 CA02 DA23 DB31 DC12 EA02 EC01 EC54 4F100 AA01A AK74 BA02 CA23A CC00B DA20 DD07A DD21 EH171 EH462 EH901 GB32 JA11A JA12A JK01 JK07A JK15 YY00A YY00B 4F202 AB05 AR19 AR01 AB01 AR01 4F208 AB19 AB25 AF01 AG05 AG07 AH18 AR06 AR12 AR13 AR20 LA01 LB01 LG01 LG22 LH02 LH06 LJ09 LW02 LW37

Claims (4)

[Claims] 1. A hollow automobile made by blow molding an amorphous resin having a tensile elastic modulus of 2000 Kg / cm ² at a temperature of 75 ° C. or higher or a crystalline resin having a flexural elastic modulus at 23 ° C. of 9000 Kg / cm ² or higher. 12 on the outer surface of the exterior plate molding
In an automotive exterior panel coated with a coating having a thickness of 0 μm or less, the surface roughness of the molded product is 3 to 13.5 μm, and the surface roughness (H) of the molded product and the film thickness (T ) Has the following formula: (H and T are in μm). T ≧ 4.5H + 10 2. The automotive exterior panel according to claim 1, wherein the temperature at which the tensile modulus is 2000 kg / cm ² is 7 ° C.
For an amorphous resin of 5 ° C. or more or a crystalline resin having a flexural modulus at 23 ° C. of 9000 Kg / cm ² or more, 3-35
An exterior panel for automobiles, characterized by blending an inorganic filler within a range of weight%. 3. A method for manufacturing an automotive exterior panel, comprising: forming a hollow automotive exterior panel by blow molding, and then applying a coating film on an outer surface of the automotive exterior panel molded article. The molding has a surface roughness of 3 to 13.5.
A mold having minute irregularities within the range of μm is used, and the tensile elastic modulus between the opened molds is 2000 kg / c.
m ² and made the temperature is closed later type were arranged parison consisting of 75 ° C. or more amorphous resin, followed by introducing a pressurized fluid into the parison is brought into close contact with the cavity surface temperature Y ° C. of the cavity Is set within a range of Y = (0.96X + 3) to (0.96X + 40) with respect to a temperature X ° C. at which the tensile elastic modulus of the amorphous resin becomes 2000 kg / cm ^2, and the coating is applied while being adhered. The production of an automotive exterior panel characterized in that the thickness of the film is within the range of 120 μm or less and the following formula is satisfied between the surface roughness (H) of the molded product and the thickness (T) of the coating film. Method (H and T
Is in μm). T ≧ 4.5H + 10 4. A method for manufacturing an automotive exterior panel, comprising: forming a hollow automotive exterior panel by blow molding, and then applying a coating film on an outer surface of the automotive exterior panel molded article. The molding has a surface roughness of 3 to 13.5.
Using a mold having fine irregularities within the range of μm, the flexural modulus at 23 ° C. between the opened molds is 9
After disposing a parison made of a crystalline resin of 000 Kg / cm ² or more, the mold is closed, and then a pressurized fluid is introduced into the parison to adhere to the cavity, and the surface temperature y ° C. of the cavity is expressed by the following formula: A < y <1.07B where: A: Flexural modulus at 23 ° C. is 9000 Kg / cm ²
Crystallization peak temperature (° C.) in DSC curve of the above crystalline resin B: Flexural modulus at 23 ° C. is 9000 Kg / cm 2
The surface roughness (H) of the molded product and the film thickness of the coating film are set within the range of satisfying the melting peak temperature (° C.) in the DSC curve of the above crystalline resin, and the thickness of the coating film to be applied is within the range of 120 μm or less. A method for manufacturing an automotive exterior panel (H and T) characterized by satisfying the following expression between the film thickness (T) and the film thickness (T).
Is in μm). T ≧ 4.5H + 10