JP4017257B2 - Manufacturing method of automotive exterior board - Google Patents

Description

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【発明の効果】
本発明は上述のとおり構成されているので、次に記載するような効果を奏する。
【００７２】
ブロー成形した自動用外装板成形品の外面に斑点や線状痕さらにはエアーマークが発生するおそれがなく、前記自動車用外装板成形品の外面を研磨や水研ぎすることなく直接塗膜を塗布するだけで、耐熱性に優れかつ外観良好な自動車用外装板を製造することができる。
【図面の簡単な説明】
【図１】型開きした金型間にパリスンを押し出した状態を示す模式断面図である。
【図２】ブロー成形された自動車用外装板成形品を金型中で冷却したのち、金型を型開きした状態を示す模式断面図である。
【図３】ブロー成形されたスポイラー成形品を示す模式斜視図である。
【符号の説明】
１ 自動車用外装板成形品
２ 押出ヘッド
３ パリスン
４，５ 金型
４ａ，５ａ キャビティ
６，７ 加熱手段
１０ スポイラー成形品[0001]
BACKGROUND OF THE INVENTION
The present invention, appearance to a method for manufacturing a good, yet automotive exterior plate having excellent heat resistance.
[0002]
[Prior art]
An example of a conventional method for producing a hollow molded article made of an amorphous resin having good appearance and excellent heat resistance will be described.
[0003]
In this method for manufacturing a hollow molded article made of amorphous resin, a split mold having a mirror-finished cavity surface is used, and the tensile modulus between the molds opened is 2000 kg / cm ^2. When a Paris made of an amorphous resin having a temperature of 75 ° C. or higher is placed, the mold is closed, and then, when the gas is blown into the Paris to be brought into close contact with the cavity, the cavity temperature Y ° C. is set to be equal to that of the amorphous resin. For a temperature X ° C. at which the tensile modulus is 2000 kg / cm ² ,
Y = (0.96X−37) to (0.96X + 3)
It is set so that it is within the range of (1), and is in close contact (Japanese Patent Publication No. 6-22875).
[0004]
[Problems to be solved by the invention]
In the case of the above-mentioned conventional technology, in the case of manufacturing an automotive exterior board that is unavoidably caused by spots and linear marks on the outer surface of the amorphous resin hollow molded product, and the appearance is strictly required. After the outer surface of the blow molded amorphous resin hollow molded product is polished or wet-polished to remove spots or line marks, a coating film must be applied to the outer surface. For this reason, there existed a problem that the number of processes increased and the manufacturing cost was raised.
[0005]
The present invention has been made in view of the above-described problems of the prior art, and a coating film is applied to an outer surface without performing polishing or water-polishing of the outer surface of a blow molded automobile exterior plate molded product. alone, it is an object to realize a method of manufacturing an automotive exterior panel, which can be obtained excellent heat resistance and no such orange peel on the painted surface appearance good automotive exterior plates.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing an automotive exterior plate according to the present invention is for an automobile in which a hollow automotive exterior plate molded product is blow-molded and then a coating film is applied to the outer surface of the automotive exterior plate molded product. In the method for manufacturing an exterior plate, the blow molding of the automotive exterior plate molded product is a micro unevenness having a surface roughness within a range of 0.9 to 9.0 μm and an average peak interval within a range of 10 to 150 μm. using a mold having a mold opening and tensile modulus between the mold is closed later type were placed Parisun the temperature at which the 2000 kg / cm ² is made of 75 ° C. or more amorphous resin, then the Parisun A pressurized fluid is introduced into the cavity to bring it into close contact with the cavity, and the surface temperature Y ° C. of the cavity is Y = (0 with respect to a temperature X ° C. at which the amorphous elastic modulus of the amorphous resin is 2000 kg / cm ^2. .96X + 3 It is characterized in that is brought into close contact set within the range of ~ (0.96X + 40).
[0008]
Furthermore, in the manufacturing method of the exterior plate for automobiles according to claim 1, the surface temperature Z ° C of the cavity at the time of mold opening completion when the mold is opened to take out the molded product for automotive exterior plates is determined by the tensile elasticity of the amorphous resin. It is effective to set it within the range of Z ≦ 0.9X with respect to the temperature X ° C. at which the rate is 2000 kg / cm ² .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the above-described conventional technology, the spots and line marks generated on the outer surface of the blow molded amorphous resin hollow molded product are caused by rough skin, die lines, and irregularities generated on the outer surface of Paris.
[0010]
By the way, rough skin is caused by the flow of the molten resin passing through the extrusion head when extruding the Paris, and is irregular irregularities of about 2 μm generated on the outer surface of the Paris.
[0011]
The die line is caused by a joining portion in the flow direction of the molten resin in the extrusion head when extruding the Paris, and is a streak-like depression having a depth of 2 to 500 μm generated on the outer surface of the Paris.
[0012]
The blister is caused by unmelted granular material or carbide of the resin, and is a 5-1000 μm protrusion or recess appearing on the outer surface of Paris.
[0013]
Therefore, as a result of repeating many experiments, the rough surface generated on the outer surface of the Paris, the spots and the linear marks generated on the outer surface of the amorphous resin molded product due to the die line and the bump are the gold having a mirror cavity. The finding that rather than using a mold, a mold having a predetermined surface roughness and minute irregularities with an average crest spacing is used in the cavity, and the surface temperature of the cavity is set to a predetermined temperature and can be suppressed by blow molding Got.
[0014]
The above findings were surprising from conventional common sense. This knowledge is more important than the following two points.
[0015]
For one thing, by raising the surface temperature of the cavity to a predetermined temperature, such as rough skin that occurs on the outer surface of Paris, die lines, and spots and line marks that are generated on the outer surface of an amorphous resin molded product It has been found that it can be removed. By raising the temperature of the surface of the Paris to a predetermined temperature, it is possible to erase the spots and line marks formed on the surface during the extrusion of the Paris. This is like giving a kind of heat treatment to Paris by the surface temperature of the cavity. This makes it possible to remove spots, line marks, and the like that could not be removed by conventional techniques.
[0016]
However, in the case of an amorphous resin molded product, when the cavity surface temperature is raised to a predetermined temperature, rough skin generated on the surface of Paris, spots and line marks generated due to die lines and bumps can be removed. However, it has been found that a crater-like material called an air mark is newly generated on the surface by such treatment. If the air mark is painted on it as it is, the air mark is reflected on the painted surface, so in the end it must be removed by polishing or water sharpening as before. End up. It has also been found that the air mark tends to occur in a complicated shape portion as the shape of the amorphous resin molded product becomes more complicated.
[0017]
Therefore, another finding is that the air mark is formed on the surface of the cavity when minute irregularities having a surface roughness within a range of 0.9 to 9 μm and an average crest interval of 10 to 150 μm are formed. Not only can this be prevented, but with such micro unevenness, even if the surface roughness of the cavity surface is larger than the surface roughness of the Paris, good results can be obtained that do not require polishing or water sharpening. That is, when the fine irregularities are particularly suitable for the coating film when the average irregularity is within the range of 10 to 150 μm, especially when the average crest interval is within the range of 10 to 150 μm, when coated on this amorphous resin molded product, The coating film enters the inside of the micro unevenness by a kind of capillary phenomenon, and as a result, a good painted surface is obtained. When the inventors actually measured the surface of Paris at the time of extrusion, the surface roughness of the surface of Paris was 3 μm and the average crest distance was 539 μm. Even if the surface roughness of the parison is small to a certain degree, the average crest spacing is large, so if the surface of the molded product is left with such a parison surface condition, the crests and troughs are painted. Since it cannot be filled with a film and the unevenness appears on the painted surface, it is expected that the painted surface such as the skin will be defective.
[0018]
In the present invention, as described above, rough skin generated on the outer surface of the Paris, die lines, spots, linear marks, etc. generated on the outer surface of the amorphous resin molded product are obtained by using a mold having a mirror cavity. Rather, it was obtained by the knowledge that the cavity can be controlled by using a mold having a predetermined surface roughness and fine irregularities with an average peak spacing, and setting the surface temperature of the cavity to a predetermined temperature and performing blow molding. Is.
[0019]
Judging from these, a coating film having a thickness of 15 to 150 μm was applied to the outer surface of a hollow automobile exterior plate molded product of an amorphous resin having a tensile modulus of 2000 kg / cm ² of 75 ° C. or higher. If the surface to be coated is a specific rough surface, that is, the surface roughness is within a range of 0.9 to 9.0 [mu] m and the average crest distance is within a range of 10 to 150 [mu] m, The surface was found to have a beautiful appearance with no yuzu skin.
[0020]
The present invention is based on the above findings.
[0021]
(1) As shown in FIG. 1, the split type having minute irregularities in which the surface roughness of the cavities 4a and 5a is within the range of 0.9 to 9.0 μm and the average crest interval is within the range of 10 to 150 μm. using a mold 4,5, mold opening has been between the mold 4 and 5, extruded Parisun 3 temperature tensile modulus is 2000 kg / cm ² is made of 75 ° C. or more amorphous resin from the extrusion head 2 Arrange.
[0022]
(2) After the above (1), the molds 4 and 5 are closed to hold the Paris 3, and then the pressurized fluid (about 7 kg / cm ²⁾ is applied to the Paris 3 with a blow needle (not shown). By introducing compressed air and expanding it, the hollow automotive exterior plate molded product 1 is blow-molded in close contact with the cavities 4a and 5a.
[0023]
In this step, when the parison 3 is brought into close contact with the cavities 4a and 5a by the heating means 6 and 7 using heating medium such as heated water, steam, and oil provided in the molds 4 and 5, the cavity 4a after the close contact is provided. , 5a 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 modulus of the amorphous resin is 2000 kg / cm ^2. It is important to keep it.
[0024]
(3) After the above step (2), the automobile exterior plate molded product 1 is cooled in the molds 4 and 5, and then the mold is opened and removed as shown in FIG. 2 to remove excess burrs.
[0025]
As a modification, the surface temperature Z ° C. of the cavities 4a and 5a at the time of mold opening when the mold is opened and the automotive exterior plate molded article 1 is taken out, and the tensile modulus of the amorphous resin is 2000 kg / cm. ^{If the} temperature is set to 2 within the range of Z ≦ 0.9X with respect to the temperature X ° C., a beautiful automotive exterior plate molded product 1 having an appearance without deformation after mold release is obtained.
[0026]
(4) After the above step (3), a coating film is applied to the outer surface of the automotive exterior plate molding 1 to produce an automotive exterior plate.
[0027]
In the present invention, the automobile exterior plate refers to a spoiler, a bumper, a trunk lid, a side molding, a fender, a bonnet, and the like, which are strictly required to have a so-called good appearance with a clear surface gloss and color tone.
[0028]
The tensile elastic modulus in the present invention indicates a value tested at a test speed of 2 mm / min using a No. 2 type test piece in accordance with JIS-K-7113. Moreover, even if it is the amorphous resin of the same kind, a different value is shown by the characteristic of each resin. An amorphous resin having a temperature at which the tensile modulus of elasticity is 2000 kg / cm ² is 75 ° C. or higher, and further 85 ° C. or higher is excellent in heat resistance. For example, modified polyphenylene oxide, polycarbonate, amorphous polyamide, ABS resin, and polysulfone. Further, the blend of amorphous resin is a blend of ABS resin and polycarbonate.
[0029]
Further, the amorphous resin in the present invention is a blend of an amorphous resin and a crystalline resin having an amorphous resin component of 30% by weight or more, and a temperature at which the tensile elastic modulus is 2000 kg / cm ^2. May be a resin of 75 ° C. or higher. For example, the blend of the amorphous resin and the crystalline resin includes a blend of modified polyphenylene oxide and polyamide, a blend of polycarbonate and polybutylene terephthalate, and the like.
[0030]
The surface roughness of the rough surface formed on the outer surface of the molded product for automobile exterior plates and the surface roughness of the micro unevenness of the cavity of the mold used are within the range of 0.9 to 9.0 μm. Is the roughness (JIS-B-0601) based on the maximum height of the cavity surface measured with a stylus electric roughness measuring instrument. It is obtained from the sum of the maximum height and the maximum depth of the valley (concave).
[0031]
This surface roughness is a curved curve (JIS-B-0601) rather than the maximum height Rmax (JIS-B-0601) due to the cross-sectional curve because the surface is often a gentle curve, particularly in the case of blow molded products. What was calculated | required by the sum of the maximum height of a peak (convex) and the maximum depth of a trough (concave) calculated | required from this was adopted. The roughness curve cutoff value at this time was 0.8 mm.
[0032]
In addition, the average crest of the rough surface formed on the outer surface of the automobile exterior plate molded product and the average crevice of the minute irregularities of the mold cavity to be used are within the range of 10 to 150 μm. The average distance between the peaks measured on the surface of the cavity with a stylus electric roughness measuring device. Here, five measurement surfaces were arbitrarily prepared and measured at a width of 4 mm each.
[0033]
The average mountain interval Sm is the interval from the point from the mountain to the valley across the parallel line of the measured length extracted from the fracture surface curve (JIS-B-0601) to the cross-section from the next mountain to the valley. Average value. The vertical magnification with respect to the roughness at this time was 20000 times or 10,000 times, and the horizontal magnification was 50 times.
[0034]
In order to form minute irregularities with a surface roughness within a range of 0.9 to 9.0 μm and an average peak interval within a range of 10 to 150 μm, a sand having a particle size of 150 to 1000 is blown, that is, Sand blasting is preferred.
[0035]
Moreover, application | coating of the coating film with respect to the outer surface of the exterior board molded article for motor vehicles forms a 15-150 micrometer coating film by spraying a coating material with an air spray gun similarly to the well-known coating method.
[0036]
【Example】
An experiment for confirming the effect of the present invention was conducted, and the result will be described.
[0037]
As an experimental example, using a blow molding machine equipped with an extruder with a screw diameter of 90 mm, as shown in FIG. 3, the length L is 1200 mm, the width D is 180 mm, the height H is 90 mm, and the average wall thickness is After blow molding the 3 mm spoiler molded article 10, a spoiler was produced in which a 50 μm coating film was applied to the outer surface of the spoiler molded article 10.
[0038]
In Experimental Examples 1 to 5, a mold having fine irregularities with a surface roughness of a cavity of 5.0 μm by sandblasting and an average peak interval of 25 μm was used, and ABS resin (manufactured by Techno Polymer Co., Ltd., YM-254, X = 105 ° C.) was extruded at 240 ° C., and the surface temperature of the cavity was changed to produce each sample.
[0039]
Experimental Example 6 is in direct proportion to Experimental Example 2, and each sample was manufactured in the same manner as Experimental Example 2 except that a mold having a mirror surface was used.
[0040]
In Experimental Example 7, Samples 1 to 9 were produced in the same manner as in Experimental Example 2 except that a mold having a micro unevenness with a cavity surface roughness of 1.0 μm and an average peak interval of 9.0 μm was used.
[0041]
In Experimental Example 8, Samples 1 to 9 were manufactured in the same manner as in Experimental Example 2 except that a mold having micro unevenness with a cavity surface roughness of 1.0 μm and an average peak interval of 10 μm was used.
[0042]
In Experimental Example 9, Samples 1 to 9 were manufactured in the same manner as in Experimental Example 2 except that a mold having minute irregularities with a surface roughness of the cavity of 5.0 μm and an average crest interval of 150 μm was used.
[0043]
In Experimental Example 10, Samples 1 to 9 were produced in the same manner as in Experimental Example 2 except that a mold having a micro unevenness with a surface roughness of the cavity of 5.0 μm and an average peak interval of 160 μm was used.
[0044]
In Experimental Example 11, Samples 1 to 9 were produced in the same manner as in Experimental Example 2 except that a mold having fine irregularities with a cavity surface roughness of 0.9 μm and an average peak interval of 25 μm was used.
[0045]
In Experimental Example 12, Samples 1 to 9 were manufactured in the same manner as in Experimental Example 2 except that a mold having fine irregularities with a cavity surface roughness of 0.8 μm and an average peak interval of 25 μm was used.
[0046]
Experimental Example 13 to Experimental Example 15 use a mold having fine irregularities with a surface roughness of a cavity of 5.0 μm and an average crest interval of 25 μm by sandblasting, and modified PPO resin (Noryl EBM-, manufactured by GE Plastics, Japan). 9201, X = 114 ° C.) was extruded at 240 ° C., and samples 1 to 9 were produced by changing the cavity surface temperature.
[0047]
Evaluation of Experimental Examples 1 to 15 is shown in Tables 1 to 15.
[0048]
The evaluation criteria in Tables 1 to 15 are as follows.
[0049]
In the table, Rt represents the surface roughness of the molded product, the unit is μm, Sm represents the average crest of the fine irregularities of the molded product, and the unit is μm. For the deformation, the appearance of the molded product after blow molding and before coating was judged visually.
[0050]
Deformation ○: Not seen.
Δ: Slightly seen, but no problem.
X: Seen.
[0051]
Rough skin ◯: There is no crusted skin-like unevenness on the surface and it is uniform.
Δ: Slightly crusted skin is observed.
X: Remarkable crust skin-like irregularities are present on the surface.
[0052]
Air mark ○: Not generated.
Δ: Almost no occurrence
X: It has occurred.
[0053]
Die line ○: Not generated.
Δ: Almost no occurrence
X: It has occurred.
[0054]
Buzz ○: Not generated.
Δ: Almost no occurrence
X: It has occurred.
[0055]
Appearance of painted surface ○: No generation of yuzu skin was observed.
(Triangle | delta): The generation | occurrence | production of the yuzu skin was seen slightly.
X: Yuzu skin was generated.
[0056]
[Table 1]

[0057]
[Table 2]

[0058]
[Table 3]

[0059]
[Table 4]

[0060]
[Table 5]

[0061]
[Table 6]

[0062]
[Table 7]

[0063]
[Table 8]

[0064]
[Table 9]

[0065]
[Table 10]

[0066]
[Table 11]

[0067]
[Table 12]

[0068]
[Table 13]

[0069]
[Table 14]

[0070]
[Table 15]

[0071]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0072]
There is no risk of spots, line marks, or air marks on the outer surface of blow molded automatic exterior panel moldings, and the coating is applied directly without polishing or polishing the outer surface of the automotive exterior panel molding. By doing this, it is possible to manufacture an automotive exterior board having excellent heat resistance and good appearance.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a state in which a Paris is extruded between molds that are opened.
FIG. 2 is a schematic cross-sectional view showing 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 schematic perspective view showing a blow-molded spoiler product.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Car exterior plate molding 2 Extrusion head 3 Paris 4, 5 Die 4a, 5a Cavity 6, 7 Heating means 10 Spoiler molding

Claims (2)

After blow molding a hollow automotive exterior plate molded product, in a method for manufacturing an automotive exterior plate in which a coating film is applied to the outer surface of the automotive exterior plate molded product,
The blow molding of the automobile exterior plate molded article uses a mold having fine irregularities having a surface roughness within a range of 0.9 to 9.0 μm and an average crest interval of 10 to 150 μm. mold opening and tensile modulus between the mold is closed later type temperature at which 2000 kg / cm ² was arranged Parisun consisting 75 ° C. or more amorphous resin and then introducing a pressurized fluid into the said Parisun Then, the surface temperature Y ° C. of the cavity is brought into close contact with the cavity, and the temperature X ° C. at which the tensile modulus of the amorphous resin becomes 2000 kg / cm ² ,
Y = (0.96X + 3) to (0.96X + 40)
The manufacturing method of the exterior plate | board for motor vehicles characterized by setting within the range of this, and making it closely_contact | adhere. 2. The method of manufacturing an automobile exterior plate according to claim 1, wherein the surface temperature Z ° C. of the cavity at the time of mold opening when the mold is opened and the automotive exterior plate molded product is taken out is expressed by the tensile modulus of the amorphous resin. For a temperature X ° C. of 2000 kg / cm ² ,
Z ≦ 0.9X
The manufacturing method of the exterior plate for motor vehicles characterized by setting within the range of this.

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