JP2000071274A - Resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molding having excellent appearance by suppressing occurrence of a weld line. SOLUTION: In the resin molding obtained by injection molding a resin composition attained by adding a lustering agent to thermoplastic resin, total light ray transmissivity of the molding in the case of 1 mm of a thickness of the molding except the agent is 25 to 65%. The composition has 0.4 to 1.0 of an FF value in the case of a mirror surface molding. This thermoplastic resin contains 60 to 95 wt.% of a nylon and 5 to 40 wt.% of a polypropylene in 100 wt.% of its resin component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention prevents the occurrence of weld lines,
The present invention relates to a resin molded product having excellent surface appearance.

[0002]

2. Description of the Related Art Conventionally, as an engine cover for an automobile,
A resin molded product that has been subjected to a metallic coating has been used. However, for cost reduction, it is required to reduce the labor and cost required for the painting work. Therefore, a resin molded product having a metallic feeling without painting is being developed.

[0003] Conventionally, in order to give a metallic feeling to a resin molded product, aluminum,
Addition of a luminous agent such as mica has been performed.

[0004]

However, when the above-mentioned conventional resin molded product is injection-molded, there is a problem that a streak-like weld line is generated at a portion where the resin flow changes, such as an opening hole and a thickness step. It is considered that the reason is that unevenness of the alignment of the brightening agent occurs starting from the resin flow changing portion.

In order to solve such a problem, as disclosed in Japanese Patent Publication No. Hei 4-27932, a weld line has a layer without a luminous agent at the tip of a resin flow during a flow process. Since a weld line is considered to occur at the joint, the relationship between the average spacing (D) of the brightener and the weld width (H) is set to D ≧ H, and the difference in appearance between the layer with the brightener and the layer without the brightener is reduced. There is a method to make the weld line inconspicuous.

We have proposed to change the compounding ratio of the luminous agent for each average particle size (Japanese Patent Application No. 9-273521).
issue). In other words, when the glitter is a scaly glitter having an average particle size of 10 to 20 μm, this is added to the thermoplastic resin 100.
Add 1 to 8 parts by weight with respect to parts by weight. Average particle size 20
In the case of a scaly luminous agent having a size of ５０50 μm, the following additive amount A is used for 100 parts by weight of the thermoplastic resin. S ≦ 5A + 15 (where S is the average particle size (μm))

The present invention has been made in view of the above-mentioned conventional problems, and is intended to suppress the occurrence of weld lines and provide a resin molded product having excellent appearance.

[0008]

The present invention relates to a resin molded product obtained by injection molding a resin composition obtained by adding a luminous agent to a thermoplastic resin, wherein the resin composition has a thickness except for the luminous agent. 1m
m when the molded product has a total light transmittance of 25 to 6
5%, and the resin composition has a FF value of 0.4 to 1.0 in the case of a mirror-finished molded product.

The resin molded article of the present invention comprises a resin composition obtained by adding a glitter to a thermoplastic resin. The resin composition comprises:
The total light transmittance in the case of forming a molded article having a thickness of 1 mm excluding the glitter is 25 to 65%. Therefore, a resin molded article made of a resin composition containing a glittering agent exhibits a glittering feeling by the glittering agent, and the weld line of the resin flow change portion becomes inconspicuous. In addition, the FF of the resin composition
The value is between 0.4 and 1.0. Therefore, a resin molded article made of the above resin composition can exhibit good-looking glitter. As described above, the resin molded product of the present invention
Weld lines are suppressed and the appearance is excellent.

Next, the details of the present invention will be described. The resin molded product is made of a resin composition obtained by adding a glitter to a thermoplastic resin. This resin composition has a total light transmittance of 2 mm when formed into a molded product having a thickness of 1 mm except for the glittering agent.
5 to 65%. "Total light transmittance" is defined as a molded product having a thickness of 1 mm, excluding a glittering agent from a resin composition.
The ratio of the outgoing light amount to the incident light amount when the molded article is irradiated with light. Therefore, when the resin molded article is made of only the thermoplastic resin and the glitter, the molded article excluding the glitter is made of only the thermoplastic resin. On the other hand, when the resin molded product contains additives such as a filler and a stabilizer in addition to the thermoplastic resin and the brightener, it also contains the thermoplastic resin and these additives.

The total light transmittance of the above resin composition is 25 to 6
5%. This makes it possible to suppress the occurrence of weld lines without causing noticeable unevenness in the orientation of the glittering agent in the resin flow changing portion while exhibiting a glittering feeling. On the other hand, if it exceeds 65%, it is preferable in terms of the appearance of glitter, but on the other hand, there is a problem that the alignment unevenness of the glitter cannot be covered and weld lines become conspicuous. If it is less than 25%, the weld line becomes inconspicuous, but on the other hand, there is a problem that the glitter is reduced.

The thermoplastic resin preferably comprises 60 to 95% by weight of nylon and 5 to 40% by weight of polypropylene resin in 100% by weight of the resin component. As a result, the total light transmittance can be favorably controlled, and it is possible to achieve both the appearance of brilliancy of the resin molded article containing the brilliant and the improvement in appearance such as prevention of weld line generation in the resin flow change portion. On the other hand, if the content of nylon is less than 60% by weight or the content of polypropylene resin is more than 40% by weight, the total light transmittance may be reduced and the glitter may be impaired.
If the content of nylon exceeds 95% by weight or the content of polypropylene resin is less than 5% by weight, unevenness in the orientation of the brightening agent cannot be covered, and the weld line may be conspicuous.

As nylon, for example, nylon 6, nylon 66, nylon 610, nylon 612,
Nylon 11, Nylon 12, Nylon 46; Nylon 6T / 60, Nylon 6T / 61, Nylon 6T /
6, an aromatic nylon such as nylon MXD6; or a transparent nylon or a mixture thereof, but is not limited thereto.

The polypropylene resin may be modified with, for example, a propylene copolymer such as homopolypropylene, a propylene-ethylene block copolymer, a propylene-ethylene random copolymer, or an acid anhydride such as maleic anhydride. Examples include, but are not limited to, polypropylene resins.

Other examples of the thermoplastic resin include nylon, polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, polybutylene terephthalate, polyethylene terephthalate, aliphatic polyketone, and polyketone. Crystalline resins such as tetramethylene terephthalate, polyacetal, polyphenylene sulfide and polymethylpentene; polystyrene, acrylonitrile styrene copolymer (AS), acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile (ethylene propylene) styrene copolymer (AES) ), Acrylonitrile (acrylate) styrene copolymer, styrene copolymer resin such as (AAS); polycarbonate, polyphenylene oxide, polyary Over DOO, polyether sulfone, polyallyl sulfone, polysulfone, polyether imide, can be used methacrylic resin, amorphous resin such as polyvinyl chloride. These can be used alone or as a mixture of two or more. As the above-mentioned thermoplastic resin, it is possible to use all thermoplastic resins having a total light transmittance of 25 to 65% when formed into a molded product having a thickness of 1 mm.

The FF value (Flip-Flop) in the above mirror-finished molded product
The value) is an index indicating the degree of orientation of the glittering agent measured by a laser glittering measurement device when the resin composition is formed into a mirror-finished product. Such an FF value is obtained by making the degree of change in reflected light intensity when the observation angle with respect to the mirror-shaped product changes, by the average reflected light intensity non-dimensional.

The FF value is 0.4 to 1.0. Therefore, a bright appearance with good appearance can be exhibited. On the other hand, 0.
If it is less than 4, the glitter is reduced and the solid feeling is enhanced, and if it is more than 1.0, the glitter is enhanced.
Brightness varies depending on the type of brightener, mixing ratio, and the like. The glittering feeling is, for example, metallic feeling, glittering feeling,
Includes glare and metallic tone. In particular, when a metallic feeling and a feeling of glare are required, the FF value is 0.5 to 1.0.
More preferably, it is within the range.

The luminous agent is, for example, a scaly luminous agent. As a scaly luminous agent, an aspect ratio of 5-200
Are preferred. If the number is less than 5, the glitter of the resin molded article may be insufficient, and if it exceeds 200, the glitter may not be uniformly dispersed. More preferably, it is 10-100. Here, aspect ratio (A) = average particle diameter (μm) / average particle diameter thickness (μm)
m).

Examples of the above-mentioned brightener include aluminum powder, mica pearl pigment, brass powder, glass powder, metal plating powder, metal coating powder and the like.
Among them, aluminum powder is preferred as a versatile luminous agent which gives a molded surface with excellent luminous feeling without noticeable weld appearance abnormality. In particular, an aluminum powder having a very smooth surface and a shape with little unevenness is effective and suitable for improving the FF value described above.

The average particle size of the above-mentioned brilliant is 10 to 300.
μm is preferred. If it is less than 10 μm,
The glitter of the resin molded product may be insufficient,
If the thickness exceeds 0 μm, the uniformity of glitter may be insufficient. A more preferred range is 30 to 150.
μm. The amount of the luminous agent added was FF value of 0.4 to 0.4.
It can be set arbitrarily within a range satisfying 1.0.

The above resin composition may contain phthalocyanine blue, cyanine green, indazulene, azo, anthraquinone, perylene, perinone, quinacridone, isoindolinone, thioindigo, etc., if necessary. Organic pigments such as dioxazine, titanium oxide, titanium yellow, red iron oxide, fired pigments, inorganic pigments such as carbon black, phthalocyanine, anthraquinone, perylene, perinone dyes, antioxidants, ultraviolet absorbers, An additive such as a coupling agent, a dispersant such as metal soap, low molecular weight polyolefin, or a reinforcing material such as talc may be added.

The resin molded product may be directly injection-molded with a resin composition in which each component is mixed in a required amount in the final molded product, or a compound comprising the resin composition may be prepared by an extruder. After this, it may be injection molded. It is also possible to prepare a dry color or a high-concentration masterbatch, dilute it with a resin to form a resin composition, and subject it to injection molding. The shape and thickness of the resin molded product of the present invention are not limited. Further, it may be either a mirror surface or a rough surface. For example, when the shape has a resin flow changing portion as shown in FIG. 1, the effect of the present invention can be effectively exhibited.

[0023] The resin molded product of the present invention comprises an engine cover,
It is suitable for various engine parts such as timing belt covers and rocker covers, engine interior parts and exterior parts such as side moldings, garnishes and pillars, home appliances parts and interior parts.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to Examples 1 to 4 in comparison with Comparative Examples 1 to 5. (Preparation of resin composition) As shown in Table 1, Nylon 6 and maleic anhydride-modified polypropylene were blended in proportions.
A glitter was added to 100 parts by weight of these resins. In some cases, talc is added as a reinforcing material. These were kneaded, and the resin compositions were subjected to the following measurements as Examples 1 to 4 according to the present invention and Comparative Examples 1 to 5 for comparison.

As the luminous agent, scaly aluminum powder A,
B and C were used. Aluminum powder A has an average particle size of 60 μm and an aspect ratio of 10. Aluminum powder B has an average particle size of 40 μm,
The aspect ratio is 25. Aluminum powder C has an average particle size of 20
μm and an aspect ratio of 50. The aluminum powders A and B are of a high-brightness type having a very smooth surface and little irregularities, and the aluminum powder C is of a general-purpose type having irregularities on the surface.

(Total light transmittance) The above various resin compositions were 1 mm thick and 80 mm ×
An 80 mm square plate-shaped molded product was formed. This molded product
There was no grain and the mirror surface was used. And 40 from the above molded product
A sample piece of mm × 40 mm was cut out. The ratio of the outgoing light amount to the incident light amount when the sample piece was irradiated with light was measured by a haze meter manufactured by Toyo Seiki Seisaku-sho, and the total light transmittance was determined. As a result, as shown in Table 1, the total light transmittance of the molded product was 33 to 33 in Examples 1 to 4.
It was within the range of 55%, with Comparative Example 1 being 76% and Comparative Example 5 being 18%.

(FF value) Mirror finished products were formed from the above various resin compositions. This mirror-finished product has a composition including a luminous agent, unlike the total light transmittance. The FF value of this mirror-finished molded product was measured with a laser-type metallic feeling measurement device (trade name: LMR-200, manufactured by Kansai Paint Co., Ltd.). As a result, as shown in Table 1, the FF value of the mirror-finished product was 0.1 in Examples 1 to 4.
57 to 0.83, 1.03 or more in Comparative Examples 1 and 3, and 0.35 or less in Comparative Examples 2, 4, and 5.

(Evaluation of Appearance) As shown in FIG. 2, a mold cavity 6 (100 mm long × 100 mm wide ×
Injection molding was performed from the gate 60 to obtain a flat molded product with holes. The flat molded product had the shape shown in FIG. 1 (a), and its surface was a mirror surface. The presence or absence of a metallic feeling of the flat molded product and the presence of weld at the downstream of the baffle disk were visually observed. ○, when there is a metallic feeling
When there was no, it was evaluated as x.ウ ェ ル indicates that no weld line was observed, and × indicates that no weld line was observed.

As a result, as shown in Table 1, Examples 1 to
In the case of No. 4, there was a metallic feeling and no weld line was observed. On the other hand, in Comparative Examples 1 and 3, although there was a metallic feeling, a weld line 8 occurred.
(A)). In Comparative Examples 2, 4, and 5, no weld line was observed, but no metallic feeling was observed. In Comparative Example 2, although a little metallic feeling was recognized,
There was a lack of glitter. Comparative Example 4 produced a flat appearance with a gentle appearance. In Comparative Example 5, it was solid.

From the above measurement results, all of the molded products of Examples 1 to 4 having good appearance characteristics have a total light transmittance of 25 to 6
It can be seen that the FF value is in the range of 5% and the FF value is in the range of 0.4 to 1.0.

[0031]

[Table 1]

(Shape of Molded Article) Next, as shown in FIG. 1, molded articles of various shapes were injection-molded from the above resin composition. That is, a molded product 71 having an opening hole 711 (FIG. 1)
(A)), a molded product 72 having a step portion 721 (FIG. 1)
(B)), a molded product 73 having a convex portion 731 (FIG. 1)
(C)), a molded product 74 (FIG. 1 (d)) in which resin was injected from both left and right sides was molded. In FIG. 1, reference numeral 60 denotes a gate for injecting the resin composition. The molded article was molded on both the mirror surface and the rough surface.

It is considered that the injected resin composition flows as shown by arrow A in FIG. In Examples 1 to 5, no weld line was generated with any shape, or even on a mirror or rough surface, but in Comparative Examples 1 and 3, a weld line was generated. The weld lines of Comparative Examples 1 and 3 were particularly conspicuous on the mirror surface.

Here, in Comparative Examples 1 and 3, in the case of FIG. 1A, the downstream side of the opening 711, in the case of FIG. 1B, around the stepped portion 721, and FIG. Around the convex, Fig. 1
In (d), the resin flow changes at the portions where the resin injected from the left and right collide. A streak-like weld line 8 was generated on the surface of the molded product at that portion.

[0035]

According to the present invention, the occurrence of weld lines can be suppressed and a resin molded article having excellent appearance can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a molded product according to an embodiment.

FIG. 2 is an explanatory view of the inside of a mold in the embodiment.

[Explanation of symbols]

 6. . . Cavity, 60. . . Gate, 61. . . Disturbing discs, 71, 72, 73, 74. . . 7. molded product . . Weld line,

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yutaka Ogasawara 1 Ochiai Nagahata, Kasuga-cho, Nishi-Kasugai-gun, Aichi F-term (reference) 4F206 AA29K AB14 AH16 AH17 AM36 JA07 JF01 JF02 4J002 BB021 BB121 BB122 BB152 BB171 BB212 BB231 BC021 BD041 BG051 BN141 BP022 CB001 CC011 CF051 CF161 CG001 CH071 CL011 CL031 CL061 CM041 CN011 CN031 DA096 DC006 DJ056 DL006 FA016 FB046 FB076 FD010 FD090 FD206 GL00 GN00 GQ00

Claims (2)

[Claims] 1. A resin molded product obtained by injection molding a resin composition obtained by adding a glitter to a thermoplastic resin, wherein the resin composition is a molded product having a thickness of 1 mm except for the glitter. A resin molded product having a total light transmittance of 25 to 65% in the case of performing the above, and an FF value of 0.4 to 1.0 when the resin composition is a mirror molded product. . 2. The resin molded article according to claim 1, wherein the thermoplastic resin comprises 60 to 95% by weight of nylon and 5 to 40% by weight of a polypropylene resin in 100% by weight of the resin component.