JP2895151B2 - Injection molding parts for cylindrical camera parts - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an injection molded part of a cylindrical camera part obtained by injection molding a material mainly containing an aromatic polycarbonate resin composition.

[Conventional technology]

In general, injection-molded parts of optical equipment such as a lens barrel of a camera, a mirror holding frame, a body, etc., have good surface smoothness and slidability and sufficient strength and rigidity in addition to high dimensional accuracy and shape accuracy. Is required.

Conventionally, in order to satisfy such demands, for example,
As disclosed in -15843, a camera component obtained by molding a composition containing an aromatic polycarbonate resin as a main component, a blend of an acrylic elastic polymer, glass fiber, and carbon black is proposed. Have been. This camera component is particularly improved in appearance.

[Problems to be solved by the invention]

However, in the above-mentioned conventional camera parts, the glass fibers or the like are oriented by the flow of the resin during molding, the molding shrinkage ratio is not constant, and it is difficult to obtain high dimensional accuracy and shape accuracy. In addition, glass fibers and the like floated on the surface, resulting in poor smoothness and slidability. Further, in a cylindrical part such as a lens barrel, it is molded by a multipoint gate, but in a weld portion formed between the gates, the strength is significantly deteriorated, and in order to obtain sufficient strength,
In many cases, there were restrictions on the shape and thickness.

The present invention has been made in view of such conventional problems, and has high dimensional accuracy and shape accuracy, particularly having a roundness of 30 mm or less, good surface smoothness and slidability, and sufficient strength. It is an object of the present invention to provide an injection molded part of a cylindrical camera part.

[Means for solving the problem]

In order to achieve the above object, the present invention provides an aromatic polycarbonate resin composition having 50 to 92% by weight, a core portion, and a needle-like crystal portion extending from the core portion in a different four-axis aroma. 3 to 40% by weight of zinc oxide whiskers, wherein the diameter of the base of the needle-shaped crystal part is 0.3 to 14 μm and the length from the base to the tip of the needle-shaped crystal part is 3 to 200 μm, and glass fiber and / or carbon fiber The composition comprising 5 to 40% by weight was injection molded to obtain an injection molded part of a cylindrical camera part having a roundness of 30 μm or less.

In the present invention, the aromatic polycarbonate resin composition is an aromatic polycarbonate resin alone, or a thermoplastic resin, an elastomer, and the like appropriately mixed therein. In the present invention, the reason for setting the amount of the aromatic polycarbonate resin composition to 50 to 92% by weight is that if it is less than 50% by weight, kneading with zinc oxide whiskers or the like becomes difficult, and the physical properties rapidly decrease. When the content exceeds 92% by weight, the linear expansion increases, the desired accuracy cannot be obtained, the smoothness deteriorates, and the improvement in strength cannot be expected. It is.

The aromatic polycarbonate resin is obtained by a method similar to a conventional method for producing a polycarbonate resin, that is, by reacting an aromatic dihydric phenol compound with phosgene or a carbonic acid diester. The aromatic homo- or co-polycarbonate resin used in the present invention preferably has a viscosity average molecular weight of 15,000 to 30,000.

Here, as the aromatic dihydric phenol compound, 2,2
2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-di-tylphenyl) propane, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ) Ethane, 2,2-bis (4
-Hydroxyphenyl) butane, 2,2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dipropylphenyl) propane, 1,1-bis (4-Hydroxyphenyl) cyclohexane, 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane and the like are exemplified, and they are appropriately used alone or as a mixture of two or more.

As the molecular weight regulator, ordinary phenol, P
-T-butylphenol, tribromophenol, etc.
Long-chain alkyl-substituted phenols such as octylphenol, norylphenol and laurylphenol; long-chain alkyl esters of hydroxybenzoic acid such as octyl hydroxybenzoate, lauryl hydroxybenzoate and noryl hydroxybenzoate; octyl ether phenol (= octyloxyphenol); Examples thereof include monohydric phenol compounds such as long-chain alkyloxyphenols such as phenyl ether phenol and lauryl ether phenol, and the amount used is in the range of 1 to 10 mol%, preferably 2.0 to 3.5 mol% of the dihydric phenol used. is there. Further, it can be used as a branched one, and as a branching agent, phloroglysin, 2,6-dimethyl-2,4,6-tri (4
-Hydroxyphenyl) heptene-3,4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-
2,1,3,5-tri (2-hydroxyphenyl) benzol, 1,1,1-tri (4-hydroxyphenyl) ethane,
2,6-bis (2-hydroxy-5-methylbenzyl)-
Polyhydroxy compounds exemplified by 4-methylphenol, α, α ′, α ″ -tri (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, and 3,3
-Bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chlorisatin,
Examples thereof include 5,7-dichlorisatin and 5-bromoisatin, and the amount used is in the range of 0.02 to 1.0 mol% of the dihydric phenol used.

As thermoplastic resins, crystalline thermoplastic polyester resins such as PET and PBT; liquid crystal polyesters and resins such as copolymers of wholly aromatic polyesters and polyesters having a resin group chain; PS, HIPS, AS, MS, ABS, MBS, EPDM-SAN,
Styrene resins such as AES, AAS, MAS; Acrylic resins such as PMMA; Nylon-6, Nylon-12, MXD6 and other polyamide resins; Polyolefin resins such as PE and PP; Polyphenylene ether, Polysulfone, Polysulfone,
Examples thereof include thermoplastic resins exemplified by polyether sulfone and various other engineering plastics, and one or more of them may be used in combination.

As the elastomer, polyester elastomer,
Elastomer such as polyamide elastomer, styrene-butadiene-styrene block copolymer or hydrogenated product thereof, copolymer rubber such as alkyl acrylate and alkyl methacrylate, ethylene-propylene or ethylene-propylene-diene copolymer rubber Thermoplastic elastomers exemplified by, for example; core-shell structures formed by graft polymerization of glassy resin around polybutadiene, acrylic rubber, etc., other multilayer elastomers, so-called "gel rubber" having a multicellular structure, etc. And used for impact resistance and compatibility as appropriate.

Further, in the present invention, a flame retardant and other additives can be appropriately used in combination. As the flame retardant, halogenated polycarbonate using tetrabromobisphenol A or an oligomer thereof, polydibromophenylene oxide, bis (pentabromo Aromatic flame retardants such as phenoxy) ethane, brominated polystyrene, tetrabromobisphenol S, and ethylenebistetrabromophthalimide; and organic phosphorus bromide such as triphenylphosphonium bromide and triphenyl-n-butylphosphonium bromide. Flame-retardant aids such as flame retardants, antimony compounds such as antimony trioxide, antimony tetroxide, and diantimony pentoxide.

On the other hand, the zinc whisker for oxidation used in the present invention has a substantially tetrapod shape composed of a core portion and needle-like crystal portions extending in four different directions from the core portion, and the diameter of the base of the needle-like crystal portion is 0.3. 1414 μm and the length from the base to the tip is 3-200 μm. If the amount of the zinc oxide whisker is 3 to 40% by weight, the effect of improving the orientation, improving the weld strength and imparting the slidability cannot be sufficiently exhibited if the amount is less than 3% by weight. %, The mixing becomes difficult and the improvement of the predetermined effect cannot be expected.

Further, in the present invention, as the glass fiber and the carbon fiber, conventional ones conventionally used are used. Further, the amount of the glass fiber and / or the carbon fiber is set to 5 to 40% by weight.
If it is less than 10% by weight, the reinforcing effect is reduced,
On the other hand, if it exceeds 40% by weight, mixing becomes difficult and molding anisotropy becomes large.

[Action]

In the injection molded part of the camera part having the above configuration, the substantially tetrapod-shaped zinc oxide whisker prevents the glass fiber or the carbon fiber from being aligned in one direction due to the flow, and the glass fiber in the aromatic polycarbonate resin composition. And the orientation of the carbon fiber is randomly oriented. Therefore, molding shrinkage becomes more isotropic, and higher dimensional accuracy and shape accuracy can be obtained.

In addition, the floatation of the glass fiber or the carbon fiber on the surface of the molded product is prevented by the zinc oxide whisker, and the zinc oxide whisker protruded on the surface of the molded product has very good surface smoothness and slidability.

Further, at the weld portion of the molded product, the glass fiber or the carbon fiber randomized by the zinc oxide whiskers is oriented in a direction closer to a right angle to the weld line, so that the molded product has a high weld strength.

〔Example〕

(First Embodiment) FIG. 2 shows a helicoid frame 1 which is an injection molded part of a camera part of the present embodiment.
Has a cylindrical shape with a diameter of 60 mm, a shaft length of 70 mm, and a wall thickness of 1.5 mm,
A helicoid screw 2 is formed on the inner wall surface 1a. Further, on one end face 1b of the helicoid frame 1, three gates 3 formed by injection molding are provided. Further, three weld lines 4 are formed on the peripheral side surface 1c of the helicoid frame 1.

The helicoid frame 1 having such a configuration is formed of a material having a composition as shown in the following table. Specifically, polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., Iupilon S-
2000), zinc oxide whisker (Matsushita Sangyo Kikai Co., Ltd., Panatetra), glass fiber (CSO3MA409C, manufactured by Asahi Fiberglass Co., Ltd.), carbon fiber (Vesfight HTA-C6-SRS-GF, manufactured by Toho Rayon Co., Ltd.) ) Was used.

In the evaluation items in the above table, the roundness (μm) is the amount of deviation of the outer periphery of the helicoid frame 1 from a perfect circle. The compressive breaking strength (kgf) is the strength when compressed on a plane in the direction indicated by arrow F in FIG. Rotation starting torque (g
· Cm), when the helicoid screw 2 of the helicoid frame 1 is screwed into a standard screw member (not shown),
Is the minimum torque that can be rotated in the direction of arrow T in FIG.

(Second to Fifth Examples, Comparative Examples 1 and 2) A helicoid frame having the same shape as that of the first example was formed of a material having the composition shown in the above table.

As is clear from the evaluation results shown in the table, the first to fifth
The helicoid frames of the examples have smaller roundness, higher compressive breaking strength, and lower rotation starting torque than the helicoid frames of Comparative Examples 1 and 2.

Here, the reason why the roundness of the example is smaller than that of the comparative example is that the anisotropy of molding shrinkage by injection molding is smaller. This is because, when the helicoid frame is formed by injection molding, in the comparative example, the direction of the glass fiber or carbon fiber in the helicoid frame is not random but aligned in a certain direction due to the flow of the resin. Therefore, the molding shrinkage does not become isotropic, and the roundness increases. On the other hand, in the embodiment, the directions of the glass fibers and the carbon fibers are randomized and made isotropic by the four-direction projections of the zinc oxide whiskers. for that reason,
The molding shrinkage becomes isotropic, and the roundness is reduced.

This is especially evident at the weld line. FIG. 1 and FIG. 3 are enlarged views of the structure of the helicoid frame 1 in the weld line 4 of the first embodiment and the comparative example 1, respectively. As shown in FIG. 1, in the case of the first embodiment, the glass fibers 6 are randomly oriented in the polycarbonate resin 5. This is because the orientation of the glass fiber 6 is hardly affected by the flow of the injection molding due to the zinc oxide whisker 7.

On the other hand, as shown in FIG. 3, in the case of Comparative Example 1, the longitudinal direction of the glass fiber 6 in the polycarbonate resin 5 is substantially parallel to the weld line 4.

The orientation of the glass fiber 6 at the weld line 4 also affects the compressive breaking strength.

On the other hand, the strength of the helicoid frame of the comparative example is low because the fibers are aligned at the weld line, so that the reinforcing effect at the weld line can hardly be exhibited. On the other hand, the helicoid frame of the embodiment has a reinforcing effect by the fiber, and the strength is improved.

In addition, the rotation starting torque is smaller in the example than in the comparative example because the zinc oxide whiskers considerably prevent the glass fiber and the carbon fiber from floating on the surface of the helicoid screw portion of the helicoid frame.
The sliding resistance on the surface is reduced.

〔The invention's effect〕

As described above, according to the injection molded part of the cylindrical camera part of the present invention, the composition comprising the predetermined aromatic polycarbonate resin composition, zinc oxide whisker, glass fiber and / or carbon fiber is injection molded. As a result, the dimensional accuracy and shape accuracy are high, especially, the molding shrinkage ratio is isotropic, and the roundness is 30 μm or less,
In addition, the surface smoothness and slidability are good and have sufficient strength, and the cost is low.

[Brief description of the drawings]

FIG. 1 is an enlarged view showing a structure of a helicoid frame of a first embodiment of the present invention at a weld line, FIG. 2 is a perspective view showing a helicoid frame of the first embodiment of the present invention, and FIG. 3 is a comparative example. It is an enlarged view which shows the structure in the weld line in 1 helicoid frame. DESCRIPTION OF SYMBOLS 1 ... Helicoid frame 4 ... Weld line 5 ... Polycarbonate resin 6 ... Glass fiber 7 ... Zinc oxide whisker

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 7:06 7:08 7:14) B29K 69:00 105: 12 B29L 23:00 (72) Inventor Toshio Matsukura 2 Hatagaya, Shibuya-ku, Tokyo Chome 43-2 O Olympus Optical Industry Co., Ltd. (72) Inventor Toshiaki Izumida 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Mitsubishi Plastics Chemical Co., Ltd. Plastic Center (72) Inventor Sangoro Kango 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Japan Mitsubishi Plastics Chemical Co., Ltd. Plastic Center (72) Inventor Koujiro Matsuo 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Jun Yagi Osaka 1006 Kadoma, Kadoma City Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-162445 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 69/00

Claims (1)

(57) [Claims] 1. An aromatic polycarbonate resin composition of 50 to 92.
% By weight, and a core portion and a needle-like crystal portion extending in four different directions from the core portion, wherein the base of the needle-like crystal portion has a diameter of 0.3 to 14 μm, and the base of the needle-like crystal portion Length from to 3 to tip
3 to 40% by weight of zinc oxide whiskers of 200 μm, glass fiber and / or carbon fiber 5
An injection molded part of a cylindrical camera part having a roundness of 30 μm or less, obtained by injection molding a composition comprising 〜40% by weight.