JPH07196901A - Polyester-based resin composition and molded article of polyester-based resin - Google Patents

Abstract

PURPOSE:To obtain a polyester-based resin composition providing a molded article having excellent weld appearance and a metallic feeling, comprising a polyester-based resin and a very small plate of a metal prepared by cutting a metal plate by punching processing, etc., having a specific average particle diameter, an average shape ratio and luster. CONSTITUTION:(A) 100 pts.wt. of a polyester-based resin comprising a polycarbonate resin, a polyethylene terephthalate resin or its mixture is blended with (B) 0.2-10 pts.wt. of one or more very small plates of a metal prepared by cutting a metal plate (e.g. aluminum plate) by punching processing, etc., having 80-800mum average particle diameter, 1/100-1/8 average shape ratio (thickness/ average particle diameter) and luster to give the objective polyester-based resin composition providing a molded article useful for an OA (office automation) device, an AV (audio visual) device, a camera telephone, an electric razor, a wheel cap for automobiles, a cosmetic container, etc., having excellent weld appearance, a metallic feeling and suppressed darkening of base color.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to OA equipment, AV equipment,
The present invention relates to a polyester-based resin composition used for cameras, telephones, electric razors, automobile foil caps, cosmetic containers, and the like, and molded articles thereof.

[0002]

2. Description of the Related Art Heretofore, there has been known a method of obtaining a molded product having an excellent metallic appearance such as the brilliance of a galaxy by mixing a thermoplastic resin and a metal powder and melt-molding the metal powder. When a resin containing a resin is injection-molded, a defective appearance of a weld line or a flow pattern of the resin (hereinafter, collectively referred to as “weld appearance”) formed at a joint between resins is likely to occur. The improvement methods are roughly classified into the following two methods. First, as disclosed in, for example, JP-A-51-63847 and JP-A-61-159453, the direction of particles can be improved by using a metal powder having a relatively large average shape ratio and a relatively spherical shape. As a result, the weld appearance is improved. Secondly, as disclosed in JP-A-61-49817, the particle size and the addition amount are adjusted so that the average gap D of the metal particles and the weld width H have a relationship of D ≧ H. To improve the weld appearance.

[0003]

However, in the conventional technique using the metal powder as described above, it is not possible to prevent extremely fine particles from being mixed in because the pulverization is involved in the process of forming the metal powder. In addition, fine particles crushed by the shear received during pelletization and melt molding are mixed, and these act like black pigments, resulting in dark weld lines and flow patterns, achieving excellent weld appearance. I couldn't do it. This is exactly why the weld appearance deteriorates as the amount of metal powder added increases. Further, the fine particles have an adverse effect of darkening the molded product, and when a white pigment such as titanium white is added to improve the effect, the metallic feeling is reduced due to the hiding effect.

The present inventor added a metal microplate obtained by punching or the like to a thermoplastic resin to
We have also proposed a resin molded product that has an excellent weld appearance and an excellent metallic feel that could not be achieved with conventional metal powder obtained by pulverization. Such a resin molded product can be obtained by suppressing the mixing of extremely fine particles as much as possible at the stage of adding the metal powder. However, a filler-reinforced polyethylene terephthalate resin (hereinafter referred to as "GF-PET"),
Polyester resins such as alloy resins of polycarbonate resin (hereinafter referred to as “PC”) and polyethylene terephthalate resin (hereinafter referred to as “PET”) can be used even if the metal microplate obtained by such punching is used. However, there is a problem that the hue of the base resin is darkened and the weld appearance is deteriorated. This is because in the case of these polyester-based resins, because it is inevitable to give a high market share during melt pelletization by a twin-screw extruder or the like,
It is presumed that this is because fine particles are generated even when a metal microplate obtained by punching is used. In fact, when the molded product was observed with an electron microscope, fine particles were still observed together with the folded metal microplates.

Therefore, the present invention provides an OA equipment chassis, an AV
For high-quality molded products such as equipment chassis, camera exterior covers, automobile wheel caps, etc. where complex weld lines and flow patterns are likely to occur, it has an excellent weld appearance and metallic feel that could not be achieved by conventional technology. In addition, it is an object of the present invention to provide a polyester resin composition and a resin molded product in which darkening of the base color is suppressed.

[0006]

The object of the present invention is achieved by the following resin composition and molded articles thereof. That is, 100 parts by weight of polyester resin and an average particle size of 80 to 8 obtained by cutting a metal plate by punching or the like.
A polyester resin and a resin molded article, which comprise 0.2 to 10 parts by weight of one or more kinds of metal microplates having a gloss of 00 μm and an average shape ratio of 1/100 to 1/8.

The metal microplate used in the present invention is
It is mainly produced by punching, and can be obtained, for example, by stamping a metal sheet into an appropriate shape using a stamping machine. According to this, since a crushing step is not required when producing the metal microplate, it is possible to substantially prevent the mixing of extremely fine particles, which cannot be avoided by the conventional metal powder. Here, “substantially” means that the weight fraction of extremely fine particles having a particle size of 15 μm or less is approximately 5% or less.
A cutting method such as cutting may be used as long as the same effect as punching can be obtained in terms of preventing the mixing of extremely fine particles as described above.

The metal microplate has an average shape ratio (thickness / average particle diameter) in the range of 1/100 to 1/8. Due to the progress of scaling, the phenomenon of being folded rather than crushed is the main factor against the shear that is received during pelletization and melt molding, and it is possible to suppress the generation of extremely fine particles. If the average shape ratio is smaller than 1/100, it is actually extremely difficult to use in terms of workability in punching when manufacturing a metal microplate and handling in use. 1 /
When it is larger than 8, fine particles are often generated, so that the weld appearance is deteriorated and the molded product is darkened, which is not preferable. When it is 1/100 to 1/8, an excellent appearance having both metallic appearance and weld appearance is exhibited.

The average particle size referred to in the metal microplate means the average of the maximum lengths of the particles. The average particle size of the metal microplate is 8
It is 0 to 800 μm, and if it is smaller than 80 μm, the probability of crushing against the shear received during pelletization or melt molding increases, and extremely minute particles are not mixed in a lot. As a result, the weld appearance deteriorates. If it is larger than 800 μm, the metallic microplate will be too conspicuous to obtain an excellent appearance. When the thickness is 80 to 800 μm, an excellent appearance having both metallic feeling and weld appearance is exhibited.
Preferably 90 to 500 μm, more preferably 100 to
300 μm is preferable.

The metal microplate is added in an amount of 0.2 to 10 parts by weight. When it is less than 0.2 parts by weight, the metallic feeling is extremely weak, and when it is more than 10 parts by weight, the metal microplate is conspicuous and excellent. You can't get a metallic feel. 0.
When the amount is 2 to 10 parts by weight, an excellent appearance having both metallic appearance and weld appearance is exhibited. Desirably 0.3
-8 parts by weight, more preferably 0.5-5 parts by weight.

The shape of the metal microplate is not particularly limited. For example, in the case of a metal microplate having a symmetrical shape in the front, rear, left and right such as a square or a circle, the metal microplate is cut at one or more locations on the outer periphery. A shape having a notched concave portion, for example,
By forming a cutout in one corner of a square as shown in FIG. 1, the orientation of the metal microplates in the flow resin can be easily aligned, and a stronger metallic feeling can be obtained with a small addition amount. You can

Aluminum is the most preferable example of the metal used for the metal microplate, but copper, stainless steel,
Tin or the like may be used. Further, such a metal microplate as a base material may be subjected to a process such as baking coating of a paint or attaching a weather resistant sheet.

The metal microplates may be mixed with metal microplates having several particle sizes in order to improve the metallic feeling. However, in this case, the weld appearance is deteriorated due to the difference in flowability depending on the particle size, and therefore caution is required.

The polyester resin used in the present invention is not particularly limited, but examples thereof include PC, PET, polybutylene terephthalate resin (hereinafter referred to as PBT), and two or more kinds of resins are mixed with each other. You may. Further, these resins may be mixed mainly with other resins. Furthermore, in the case of a transparent or translucent resin, an excellent metallic feeling with a greater depth can be obtained. In addition, various colorants, fillers, stabilizers, release agents, flame retardants and the like can be added within a range that does not impair the effects of the present invention. For example, by adding carbon black or the like to color the resin, it is possible to obtain the appearance of a galaxy shining in the clear night sky.

The resin molded article of the present invention is a method in which a thermoplastic resin and a metal microplate are extrusion-molded, or a melt-pelletized product obtained by an extruder or the like is molded by injection molding or the like.
Further, it can be obtained by a method of directly kneading a thermoplastic resin and a metal microplate with an injection molding machine. The method of melting and pelletizing the thermoplastic resin and the metal microplate is preferable because the dispersibility of the metal microplate is improved. Weld appearance is further improved by selecting mild conditions during melt pelletization and suppressing crushing of the metal microplates as much as possible.

[0016]

EXAMPLES The present invention will be described more specifically by showing Examples and Comparative Examples below. The weld appearance, metallic appearance, and darkness of the base hue were visually evaluated by molding the weld appearance evaluation molded product shown in FIG. The numerical value in the figure is mm, and the wall thickness of this evaluation molded product is 2 mm.
In the figure, A is a gate (2 places), and B is a weld generating part. In addition, ⊚ in Table 1 indicates that the weld appearance and metallic appearance are extremely good, and the base color has no darkening.
The following are good in the order of ○, Δ, and ×. Further, the shape having a notched concave portion at one corner of the square in the embodiment is the shape shown in FIG. In FIG. 1, the symbol a represents the length of one side of the square.

Example 1 PC / PET = 70/30
(Weight ratio) 0.5 parts by weight of phosphite stabilizer, MB
Aluminum microplate obtained by punching (average grain size: 100 parts by weight of resin containing 0.4 parts by weight of S resin), having an average shape ratio of 1/10, and a notched recessed portion at one corner of a 200 μm side square A material to which 1 part by weight of 283 μm) was added was molded by an injection molding machine under the following molding conditions.

Molding conditions: Material drying 130 ° C., 4 hours Cylinder temperature 270 ° C., 270 ° C., 260 ° C., 2
40 ° C. Injection pressure 1000 kg / cm ² Mold temperature 60-65 ° C.

The obtained molded product had a sufficient metallic appearance and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

Example 2 A molded product was produced under the same conditions as in Example 1 except that the average shape ratio of the aluminum microplate obtained by punching was set to 1/20 and the addition amount was set to 0.4 part by weight. Molded. The obtained molded product had a sufficient metallic appearance and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

Example 3 A molded product was molded under the same conditions as in Example 2 except that the amount of aluminum microplate obtained by punching was 8 parts by weight. The obtained molded product had an extremely excellent metallic appearance and an excellent weld appearance, and had an appearance with little darkening of the base hue, and could be used as a high-grade molded product.

Example 4 A molded product was molded under the same conditions as in Example 1 except that the average shape ratio of the aluminum microplate obtained by punching was set to 1/90. The obtained molded product had an extremely excellent metallic feel and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

[Embodiment 5] An aluminum microplate obtained by punching is 100 μm with an average shape ratio of 1/20.
A molded product was molded under the same conditions as in Example 1 except that a square having a notch and a recess was formed at one corner of the side (an average particle size of 141 μm). The obtained molded product had a sufficient metallic appearance and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

Example 6 An aluminum microplate obtained by punching was 200 μm with an average shape ratio of 1/90.
Square with sides (without notches and recesses) (average grain size 2
The molded product was molded under the same conditions as in Example 1 except that the thickness was 83 μm). The obtained molded product had a sufficient metallic appearance and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

[Embodiment 7] An aluminum microplate obtained by punching has an average shape ratio of 1/60 and a diameter of 100.
A molded product was molded under the same conditions as in Example 1 except that the shape was circular (there was no cutout recess). The obtained molded product had a sufficient metallic appearance and excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

[Embodiment 8] A punched metal microplate is
An average shape ratio of 1/40 and a square of 200 μm side (without notches and recesses) made of stainless steel (average particle size 28
A molded product was molded under the same conditions as in Example 1 except that the thickness was 3 μm). The obtained molded article has a sufficient metallic feeling,
It also had an excellent weld appearance and had an appearance without darkening of the base hue, and could be used for high-grade molded products.

[Example 9] PC / PET with thermoplastic resin
= 85/15 (weight ratio), the molded product was molded under the same conditions as in Example 5. The obtained molded product had a sufficient metallic appearance and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

[Embodiment 10] PC / PE is used as a thermoplastic resin.
A molded product was molded under the same conditions as in Example 5 except that T = 30/70 (weight ratio). The obtained molded product had a sufficient metallic appearance and an extremely excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

Example 11 G was added to 84.2 parts by weight of PET.
F15 parts by weight, 0.4 parts by weight of phenolic stabilizer, 0.2 parts by weight of phosphite stabilizer, and 0.2 parts by weight of crystal nucleating agent were added to 100 parts by weight of resin, and an average shape ratio of 1/20 was 500 μm. Has a notched concave portion in one corner of the side square,
A material obtained by adding 2 parts by weight of an aluminum microplate (average particle size: 707 μm) obtained by punching was molded by an injection molding machine under the following molding conditions.

Molding conditions: Material drying 140 ° C., 4 hours Cylinder temperature 280 ° C., 270 ° C., 260 ° C., 2
50 ° C. Injection pressure 1100 kg / cm ² Mold temperature 130-135 ° C.

The obtained molded product had a sufficient metallic feel and an excellent weld appearance, and had an appearance without darkening of the base hue, and could be used as a high-grade molded product.

[Embodiment 12] PET / PBT = 30/7
0 (weight ratio): 84.6 parts by weight of the mixture, 15 parts by weight of GF, and 0.4 parts by weight of a phosphite-based stabilizer were added to 100 parts by weight of a resin. Aluminum microplate obtained by punching, which has a notched concave portion (average grain size 283 μm)
The weld appearance evaluation molded product shown in FIG. 1 was molded by an injection molding machine under the following molding conditions using a material to which 3 parts by weight of was added.

Molding conditions: Material drying 130 ° C., 4 hours Cylinder temperature 270 ° C., 270 ° C., 260 ° C., 2
40 ° C. Injection pressure 900 kg / cm ² Mold temperature 65-70 ° C.

The obtained molded product had a sufficient metallic appearance and excellent weld appearance, and had an appearance with little darkening of the base hue, and could be used as a high-grade molded product.

[Comparative Example 1] In Example 5, the average shape ratio of the aluminum microplates obtained by punching was 1 /
What was made into 5 was made into the comparative example 1. The obtained molded product has a sufficient metallic feel and excellent weld appearance,
It had an appearance with a lot of darkening of the base hue, and could not be used for high-grade molded products. As is clear from this, if the average shape ratio of the metal microplate is too large, the base hue becomes dark.

[Comparative Example 2] Comparative Example 2 is the same as Example 6 except that the addition amount of the aluminum microplate obtained by punching is 0.1 part by weight. The obtained molded product is
It has an extremely excellent weld appearance and has no darkness in the base hue, but it has an appearance with a very weak metallic feel, which makes it unsuitable for high-grade molded products. As is clear from these, if the addition amount of the metal microplate is small, the metallic feeling becomes poor.

[Comparative Example 3] In Example 6, the addition amount of aluminum microplates obtained by punching was 12.0.
What was made into weight part was made into the comparative example 3. The obtained molded product had an excellent metallic feel, but had poor weld appearance and had an appearance with a lot of darkening of the base hue, and could not be used as a high-grade molded product. As is clear from this, when the amount of the metal microplates added is too large, not only the weld appearance becomes poor, but also the base hue becomes dark.

Comparative Example 4 In Comparative Example 4, the aluminum microplate obtained by punching was formed into a square of 50 μm side (average particle size 71 μm), and the addition amount was 5.0 parts by weight. did. The obtained molded product had an extremely excellent metallic feel, but had poor weld appearance and had an appearance with a lot of darkening of the base hue, and could not be used as a high-grade molded product. As is clear from this, when the amount of the metal microplate added is too large, poor weld appearance and dark base hue occur.

[Comparative Example 5] In Comparative Example 5, the aluminum microplate obtained by punching in Example 6 was formed into a square having a side of 700 μm (average particle size of 990 μm) and the addition amount was 1.0 part by weight. did. The obtained molded product has an extremely excellent weld appearance and has no darkening of the base hue, but the metal microplates are too conspicuous to give an appearance without a high-class impression, and are not usable for high-grade molded products. It was As described above, if the average particle size of the metal microplate is too large, the metallic feeling becomes poor.

Comparative Example 6 0.2 parts by weight of aluminum powder (average shape ratio 1/12, average particle size 90 μm) obtained by crushing instead of the aluminum microplate obtained by punching in Example 1 was used. The added one was designated as Comparative Example 6. The obtained molded product had an excellent weld appearance and no darkening of the base hue, but had an extremely weak metallic appearance, and was not usable for a high-grade molded product.

Comparative Example 7 In Example 1, 1.0 part by weight of aluminum powder (average shape ratio 1/12, average particle size 90 μm) obtained by crushing instead of the aluminum microplate obtained by punching was used. What was added was set as Comparative Example 7. The obtained molded product had poor weld appearance, lacked a metallic feel, and had an appearance with a lot of darkening of the base hue, and could not be used as a high-grade molded product.

Comparative Example 8 In Example 1, 1.0 part by weight of aluminum powder (average shape ratio 1/10, average particle size 55 μm) obtained by crushing instead of the aluminum microplate obtained by punching was used. What was added was Comparative Example 8. The obtained molded product had poor weld appearance, lacked a metallic feel, and had an appearance with a lot of darkening of the base hue, and could not be used as a high-grade molded product.

Comparative Example 9 In Example 1, 3.0 parts by weight of aluminum powder (average shape ratio 1/10, average particle size 55 μm) obtained by crushing instead of the aluminum microplate obtained by punching was used. What was added was set as Comparative Example 9. The obtained molded article has a sufficient metallic feeling,
The base hue had a large amount of darkening and the weld appearance had an extremely poor appearance, and it could not be used for high-grade molded products.

Comparative Example 10 In Example 11, 3.0 parts by weight of aluminum powder (average shape ratio 1/12, average particle size 90 μm) obtained by crushing instead of the aluminum microplate obtained by punching was used. What was added is Comparative Example 1
It was set to 0. The obtained molded product had a sufficient metallic feel, but the base hue was very dark, and the weld appearance had an extremely poor appearance. Therefore, it could not be used as a high-grade molded product.

As is clear from Comparative Examples 6 to 10, when the metal powder obtained by pulverization is used, poor weld appearance, poor metallic appearance, or darkening of the base hue is produced, and high-grade molded products are obtained. Can not be used as.

[0046]

[Table 1]

[0047]

As described above, according to the present invention, the average particle size is 80 to 800 μm with respect to 100 parts by weight of the thermoplastic resin,
The resin of the present invention contains 0.2 to 10 parts by weight of at least one metal microplate obtained by punching or the like having a gloss with an average shape ratio (thickness / average particle size) of 1/100 to 1/8. Since the molded product has an excellent metallic appearance and also has a very good weld appearance, it has a complicated structure such as OA equipment chassis, AV equipment chassis, camera exterior cover, automobile wheel cap, etc. It can also be used for high-grade molded products that are prone to weld lines and flow patterns.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a metal microplate.

FIG. 2 is a view showing a weld appearance evaluation molded product, in which (a) is a front view and (b) is a side view.

Claims (6)

[Claims] 1. 100 parts by weight of a polyester resin, an average particle size of 80 to 800 μm obtained by cutting a metal plate by punching, and an average shape ratio (thickness / average particle size) 1 /
A polyester resin composition comprising 0.2 to 10 parts by weight of at least one metal microplate having a gloss of 100 to 1/8. 2. The resin composition according to claim 1, wherein the polyester resin is a polycarbonate resin, a polyethylene terephthalate resin, or a mixture thereof. 3. The resin composition according to claim 1 or 2, wherein the metal microplate is formed in a shape having a notched concave portion at one or more locations. 4. 100 parts by weight of a polyester resin, an average particle size of 80 to 800 μm obtained by cutting a metal plate by punching, and an average shape ratio (thickness / average particle size) 1 /
A polyester resin molded article comprising 0.2 to 10 parts by weight of at least one metal microplate having a gloss of 100 to 1/8. 5. The polyester resin molded article according to claim 4, wherein the polyester resin is a polycarbonate resin, a polyethylene terephthalate resin, or a mixture thereof. 6. The polyester-based resin molded product according to claim 4, wherein the metal microplate is formed in a shape having notches and recesses at one or more locations.