JPH08118433A - Manufacture of reinforced resin cd-rom mechanism member excellent in sliding characteristic - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of a reinforced resin CD-ROM mechanism member, whose surface of at least sliding portion is made of a smooth surface and has favorable sliding characteristics. CONSTITUTION: An amorphous thermoplastic resin containing 5-50wt.% of a reinforced filler and/or an inorganic filler is injected in a mold for injection- molding a CD-ROM mechanism member under the condition that the mold wall surface, which form at least a sliding part, among the mold wall surfaces constituting the mold cavity of a metal main mold is covered with a heat insulating layer made of a heat resisting polymer having a thermal conductivity of not more than 0.002cal/cm.sec. deg.C by the thickness of 0.01-2mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a reinforced resin CD-ROM mechanism component having excellent sliding characteristics. More specifically, the present invention relates to a method of manufacturing mechanical parts such as a game machine, a music player, a computer and an AV device using a CD (compact disc) as an information medium.

[0002]

2. Description of the Related Art Recently, automobiles, office machines, computers,
In the field of home appliances, it has been attempted to replace some of the parts that used sheet metal and aluminum die casting with resin products for the purpose of weight reduction, productivity, and cost reduction. The demand is increasing. In particular, the demand for personal computers, game machines, and music players has expanded remarkably, and the use of resin for CD-ROM machines using CDs as information media has been actively studied.

Characteristics required for resin CD-ROM mechanical parts such as a traverse base chassis, a mechanical chassis, and a tray are moldability, mechanical characteristics, heat resistance, flame retardancy, dimensional accuracy, and sliding characteristics. Of these, regarding sliding characteristics,
CD-ROM mechanical parts obtained by injection molding a resin reinforced with a reinforcing filler and / or an inorganic filler have a roughened surface, and those having a large content of the reinforcing filler and / or the inorganic filler are remarkably present. Since the surface becomes rough and slidability deteriorates, it is essential to apply grease to the sliding portion.

However, particularly in a combination of a reinforced resin product and a non-reinforced resin product (for example, a combination of a mechanical chassis with a reinforced resin product and a tray with a non-reinforced resin product), a reinforced filler and / or an inorganic material of the reinforced resin product. The problem that the surface of the non-reinforced resin is gradually scraped due to the rough surface due to the floating of the filler cannot be solved by grease application, and drastic measures are required. Such a problem causes, for example, shavings to be attached to the optical lens and the CD to cause a reading failure, or shaving causes a dimensional crease, which causes a problem in slidability.

Therefore, in order to make the surface of the reinforced resin molded product smooth, various molding conditions have been changed. Among the factors at the time of molding, it is the mold temperature that has the greatest effect on the smoothness of the surface of the molded product, and the higher the mold temperature, the more preferable. However, when the mold temperature is high, the cooling time required for cooling and solidifying the plasticized resin becomes long and the molding efficiency is lowered.

For this reason, there is a demand for a resin CD-ROM mechanism component which has good surface reproducibility without raising the die temperature and does not require a long cooling time even if the die temperature is raised. Has been done. Heating holes and cooling holes are attached to the mold, and heating medium and refrigerant are alternately flowed to heat the mold.
Although a method of repeating cooling is also used, this method has a problem that a large amount of heat is consumed and a cooling time becomes long.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a CD-ROM mechanical component made of a reinforced resin having good sliding characteristics.

[0008]

DISCLOSURE OF THE INVENTION According to the present invention, a mold cavity of a main mold made of a metal is made of an amorphous thermoplastic resin containing 5 to 50% by weight of a reinforcing filler and / or an inorganic filler. At least the mold wall surface forming the sliding portion has a thermal conductivity of 0.002 cal / cm · sec ·
0.01-2m in heat insulation layer consisting of heat-resistant polymer below ℃
CD-RO injection-molded using m-thick mold
This is a method of manufacturing M mechanical parts.

Hereinafter, the present invention will be described in detail. Examples of the reinforcing filler used in the present invention include fiber reinforcing agents such as glass fibers, carbon fibers, ceramic fibers, and metal fibers, and inorganic particles such as glass beads. Examples of the inorganic filler include glass flakes, scale-like inorganic fillers such as mica, talc, and oxides such as magnesium, aluminum, silicon, calcium, potassium, titanium, carbonates, silicates, and sulfates. Types are also possible.

From the balance of dimensional accuracy and mechanical properties, glass flake, glass flake and mica combination, glass fiber and glass flake combination, glass fiber and mica combination, glass fiber and glass flake, mica combination are preferably used. it can. The amount of the reinforcing filler and / or the inorganic filler added is 5 to 50% by weight (based on the total composition), and can be selected as necessary within this range. A composition containing 10 to 40% by weight can be more preferably used in terms of performance and moldability as a CD-ROM mechanical component.

As the glass fiber, those having a commonly used diameter can be used, and those having a diameter of, for example, 5 to 50 μm are preferable. Particularly preferably, the glass fiber is 5 to 15 μm.
Furthermore, the closer the reinforcing filler or inorganic filler and the resin are to each other, the better the sliding characteristics of the CD-ROM mechanism component of the present invention, which is preferable. In order to improve the adhesion between the reinforcing filler or the inorganic filler and the resin depending on the characteristics of the resin, vinylsilane,
Those treated with a commonly used surface treatment agent such as aminosilane and chromium compound can be favorably used.

The glass flake has a major axis of 1 after blending with a resin.
It is 000 μm or less, preferably in the range of 1 to 500 μm, and has an aspect ratio (ratio of major axis and thickness) of 5 or more, preferably 10 or more, more preferably 30 or more. Mica is, for example, Sudrite Mica (trademark)
(Manufactured by Kuraray Co., Ltd.) can be used favorably. Average flake diameter after resin blending is 1000 μm or less, preferably 50
It is preferably 0 μm or less, more preferably 200 μm or less, and the weight average aspect ratio (average diameter of flakes / average thickness) is 10 or more, preferably 30 or more.

As the amorphous thermoplastic resin to which the reinforcing filler and / or the inorganic filler is added, polystyrene, rubber-modified polystyrene, AS resin, polystyrene resin such as ABS resin, polycarbonate resin, polycarbonate alloy resin (for example, Alloy resin with ABS resin),
Polyphenylene ether resins (for example, rubber-modified polystyrene, polyamide resins, alloy resins with polyolefin) and engineering resins such as polyetherimide, polysulfone, polyarylate, and polyethersulfone can be favorably used.

As the resin reinforced with the reinforcing filler and / or the inorganic filler used in the CD-ROM mechanism component of the present invention, a reinforcing resin called low warp grade can be particularly favorably used. If a lubricating material such as silicone oil (eg, dimethyl silicone, methylphenyl silicone, fluorine-modified silicone, etc.), fluororesin, molybdenum disulfide, etc. is added to these synthetic resins as necessary, the C
The sliding characteristics of the D-ROM mechanism parts are further improved, which is preferable.

The non-crystalline thermoplastic resin described in the present invention means a resin composed of 50 wt% or more of non-crystalline resin as a resin component. Therefore, it includes a polymer alloy and a polymer alloy containing less than 50% by weight of a crystalline resin as a resin component. Further, the resin composition of the CD-ROM mechanism component of the present invention is a phosphorus-based or brominated flame retardant, a phenol-based, phosphorus-based, hindered phenol-based antioxidant, etc. Agents, colorants such as titanium oxide and carbon black, lubricants such as metallic soaps, flow improvers, reinforcing thermoplastic elastomers such as styrene-butadiene block-based and polyesteramide-based additives can be added in desired amounts.

The main metal mold used in the method of manufacturing the CD-ROM mechanism component of the present invention is generally made of steel, aluminum or an alloy containing aluminum as a main component, zinc alloy, beryllium-copper alloy, or the like. It includes metal molds used for molding synthetic resins. Particularly, steel materials can be used favorably. The heat-resistant polymer used in the heat insulating layer in the present invention means a heat-resistant polymer having a glass transition temperature of 150 ° C or higher, preferably 190 ° C or higher and / or a melting point of 250 ° C or higher, preferably 280 ° C or higher. The heat conductivity of the heat resistant polymer is 0.002 cal / cm · sec · ° C. or less, and that of a general polymer is less than this heat conductivity. Further, a tough polymer having a fracture elongation of the heat resistant polymer of 10% or more is preferable.
The fracture elongation is measured according to ASTM-D638,
The tensile speed at the time of measurement is 5 mm / min.

The polymer which is preferably used in the present invention as the heat insulating layer is a heat resistant polymer having an aromatic ring in the main chain, and particularly preferably used are various amorphous heat resistant polymers which are soluble in an organic solvent. Polymers and various polyimides. Examples of the non-crystalline heat resistant polymer include polysulfone, polyether sulfone, polyallyl sulfone, polyarylate, polyphenylene ether, polybenzimidazole and the like. The repeating units of these typical heat resistant polymers are shown below.

[0018]

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[0019]

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[0020]

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[0021]

[Chemical 4]

[0022]

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There are various kinds of the above-mentioned polyimides, but a linear high-molecular-weight polyimide is preferably used. Generally, the straight-chain high-molecular-weight polyimide has a large fracture elongation and excellent durability. Examples of linear type high molecular weight polyimides which are preferably used in the present invention are shown in Table 1. In addition, Tg represents a glass transition temperature, and n represents the number of repeating units.

[0024]

[Table 1]

The linear type high molecular weight polyimides have different Tg depending on the constituents, and examples thereof are shown in Tables 2 and 3.
The Tg of the straight-chain high-molecular-weight polyimide used favorably in the present invention is preferably 150 ° C. or higher, more preferably 1
90 ° C or higher, particularly preferably 230 ° C or higher.

[0026]

[Table 2]

[0027]

[Table 3]

Table 4 shows various soluble polyimides which can be dissolved in a solvent which is favorably used in the present invention.

[0029]

[Table 4]

Injection molding has economic value in that a molded product having a complicated shape can be obtained by molding once. It is important to coat the surface of this complicated mold with a heat-resistant polymer and firmly adhere to it. Apply a heat-resistant polymer solution and / or a heat-resistant polymer precursor solution, and then heat to heat resistance. Most preferably, a polymer is formed. Therefore, the heat resistant polymer and the heat resistant polymer precursor used in the present invention are preferably soluble in a solvent.

The above-mentioned non-crystalline heat-resistant polymer, soluble polyimide and polyimide precursor are tetrahydrofuran,
Dimethylformamide, dimethylacetamide, N-
It is soluble in various solvents such as methylpyrrolidone.
The linear polyimide precursor is synthesized, for example, by subjecting an aromatic diamine and an aromatic tetracarboxylic dianhydride to a ring-opening polyaddition reaction.

[0032]

[Chemical 6]

These linear polyimide precursors are heated to undergo a dehydration cyclization reaction to form a polyimide. The most preferable linear polyimide precursor is polyamic acid, and the repeating unit of a typical example of Sori and the repeating unit of a polyimide obtained by imidizing the same are shown below.

[0034]

[Chemical 7]

[0035]

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[0036]

[Chemical 9]

[0037]

[Chemical 10]

The above polyimide precursor polymer is N
-Dissolve in a solvent such as methylpyrrolidone and apply it on the mold wall surface. To these heat-resistant polymer solutions or heat-resistant polymer precursor solutions, the viscosity at the time of coating, the surface tension of the solution, the additive for adjusting the thixotropy, or the mold may be added. It is possible to add a small amount of additive for improving the adhesion with the. Although the heat-resistant polymer used for the heat insulating layer has been described as the amorphous heat-resistant polymer and the polyimide, the present invention is not basically limited to these. Epoxy resin, silicone resin and the like having flexibility are usable depending on molding conditions.

In the present invention, a material having a large adhesion between the heat resistant polymer film and the main mold is used, more preferably 0.8 kg / 10 mm width or more, particularly preferably 1 kg /
The width is 10 mm or more. This adhesive force means that the adherent heat insulating layer is cut into a width of 10 mm, and is 20 mm /
It is the peeling force when pulled at a speed of minutes. This peeling force varies considerably depending on the measurement location and the number of measurements, but
It is important that the minimum value is large, and stable and large peeling force is preferable. The adhesion force described in the present invention is the minimum value of the adhesion force of the main part of the mold.

In order to further improve the smoothness of the surface of a thin layer of a heat insulating material such as polyimide, or to further improve the scratch resistance of the surface, or to improve the releasability, the thickness of the polyimide layer or the like is increased. If necessary, it is possible to use a material having a thickness of less than 1/10, which is made of another material, and coated on the polyimide surface or the like. As another material for the surface coating, various metals can be used in addition to the heat resistant resin as long as they are thin. Further, it is possible to use a synthetic resin sheet or mold surface coated with a coating generally called a hard coat, which is used for improving scratch resistance. Further, for example, a thermosetting type silicone hard coating agent, particularly a hard coating agent having excellent adhesion, which is a mixture of a silicone type hard coating agent and an epoxy type substance, is preferable for the present invention. It is also possible to favorably use a product coated with a fluororesin or a silicone-based polymer in order to improve releasability.

When the content of the reinforcing filler and the inorganic filler is large, the heat insulating layer on the mold surface is easily scratched during molding. In such a case, the heat insulating layer is hard and has excellent scratch resistance. If a metal layer such as chrome is attached, a CD-ROM mechanical component having good sliding characteristics can be obtained.
When a mold in which a mold wall forming a main mold cavity made of metal is covered with a heat insulating layer is used for injection molding, the mold surface is heated by the heat of the injected synthetic resin itself. Therefore, it is possible to obtain the same effect as that obtained by molding by setting the temperature of the main mold high. In order to improve the mold surface reproducibility of molded products and the smoothness of molded products, it is necessary to keep the injected resin in contact with the mold wall surface, and at least a certain amount of pressure is applied to the resin to press it against the mold wall surface. Only during this period, it is necessary that the mold surface temperature be maintained above the softening temperature of the resin. When a mold in which the mold wall surface is covered with a heat insulating layer is used, the mold surface is heated by the heat of the injected resin due to the heat insulating effect of the heat insulating layer, improving mold surface reproducibility,
The smoothness of the molded product is improved.

The CD-ROM mechanical component of the present invention having excellent sliding characteristics is reinforced by injection molding using a mold in which at least the mold wall surface corresponding to the sliding portion is covered with the above-mentioned heat insulating layer. Reinforcement filler or inorganic filler in a resin molded product containing a filler or an inorganic filler is less likely to protrude to the surface of the molded product. Therefore, the thickness of the heat insulating layer that covers the mold wall surface needs to be sufficient to achieve this purpose.

The thickness of the heat insulating layer is appropriately selected within the range of 0.01 to 2 mm. It is preferably 0.1 to 0.5 mm. If it is less than 0.01 mm, the effect is low, and if it exceeds 2 mm, it is unnecessary. Thickness (cm) / thermal conductivity (cal
/Cm.sec..degree. C.) value of 5 to 100 is particularly good for the present invention, and such a very narrow range is particularly effective. If it is smaller than the range of 5 to 100, the mold surface reproducibility tends to deteriorate, and if it is larger than this range, the cooling time in the mold tends to be long, and the mirror-like coating of the low thermal conductive material tends to be difficult. Often occurs.

In the CD-ROM mechanical part of the present invention, the mold surface temperature is kept at least 0.1 seconds after the main mold temperature is cooled to 80 ° C. or less and the injected synthetic resin comes into contact with the mold surface. Is preferably molded at 100 ° C. or higher. The temperature of the main mold is more preferably 80 ° C. or lower and room temperature or higher. Generally, the mold temperature is 80 ° C. or less for injection molding, and if the mold temperature is higher than 80 ° C., the molding cycle time becomes long and the molding efficiency decreases. When the temperature is lower than room temperature, dew condensation occurs on the surface of the mold. The change of the mold surface temperature during injection molding is the temperature of the synthetic resin composition, the main mold, the heat insulating layer,
It can be calculated from specific heat, thermal conductivity, and density. For example ADIN
A and ADINAT (software developed at the Massachusetts Institute of Technology) and the like can be used to calculate by unsteady heat conduction analysis by the nonlinear finite element method.

As a matter of course, the smoother the surface of the molded product corresponding to the sliding portion of the CD-ROM mechanism component of the present invention, the smaller the sliding resistance and the better the slidability. C
The D-ROM mechanical component is generally required to be a molded product having high bending rigidity and tensile strength as mechanical properties. Therefore,
The amount of the reinforcing filler and / or the inorganic filler to be added to the amorphous resin is generally 5 to 50 (based on the total composition), preferably 10 to 40% by weight. If such a reinforcing filler and / or inorganic filler is blended, the surface of the molded product will be deteriorated by ordinary injection molding, and the slidability will be deteriorated.

In the present invention, the main mold is cooled, and the mold surface corresponding to at least the sliding portion of the molded product is covered with the heat insulating layer. When the heat-plasticized reinforcing filler or inorganic filler is injection-molded into the mold covered with the heat insulating layer, the heat insulating layer is heated by the heat of the injected resin itself, and the temperature of the main mold becomes high. The same effect as obtained by molding can be obtained. That is, the mold cavity portion covered with the heat insulating layer has a smooth molded product surface in which the reinforcing filler or the inorganic filler protruding to the surface of the molded product is significantly reduced.

The CD-ROM mechanism component obtained by the production method of the present invention has a surface in which the reinforcing filler or the inorganic filler does not substantially protrude from the surface of the molded product at least in the portion corresponding to the sliding portion. It is an injection molded product with excellent sliding characteristics. The CD-ROM mechanical component obtained by the present invention is
Molding is performed by using a mold in which a heat insulating layer is coated on the wall surface of the mold corresponding to at least the portion where sliding characteristics are required. When the sliding portion is the convex portion of the molded product (the concave portion of the mold), the heat insulating layer is provided only in the concave portion of the mold. In this case, it is preferable to provide pores for degassing at the time of molding in the concave portions of the mold. In addition to the sliding portion, a smooth surface layer can be formed as necessary (for example, a portion requiring a good appearance) by the same means as described above.

The CD-ROM mechanical parts described in the present invention include CD (compact disc), LD (laser disc), and magneto-optical disc (MD (trademark mini disc).
Etc.), optical disc, FD (Floppy disc), HD
Mechanical components such as a (hard disk) that uses a disk as an information medium to write and read by light or magnetism, such as a computer, a game machine, a music player, and an AV device, are collectively referred to.

[0049]

EXAMPLES The sliding characteristics of the CD-ROM mechanism component containing the reinforcing filler resin and / or the inorganic filler of the present invention will be described in detail below with reference to Examples. The resin composition shown in Table 5 was prepared by the following method. (1) Surface smoothness According to JIS-B0601, the surface roughness of a flat plate is a three-dimensional surface roughness profile measuring device, Surcom 570A manufactured by Tokyo Seimitsu Co., Ltd.
The center line average roughness Ra was measured using -3D. (2) Sliding property Diameter of 2.5mmR (tip diameter 0.9mmφ) 5mmφ
While pressing the pin of No. 2 against the flat plate test piece with a load of 2 kg, a one-way distance of 10 mm is applied at a speed of 30 mm / sec for 10 minutes.
In the friction / wear acceleration test of reciprocating 000 times,
The friction coefficient immediately before the end of the test and the amount of wear after the end of the test were evaluated by the wear depth.

[0050]

[Examples 1 to 3] Using the following main molds or polyimide-coated molds, 100 mm x 100 mm x 3 mmt flat plate test pieces and pins were prepared under the resin composition, combination and molding conditions shown in Table 5. Then, the surface smoothness and slidability were evaluated. The results are shown in Table 5. The obtained molded product had less protrusion of the reinforcing filler and the inorganic filler, had a smooth surface, and had good slidability. (A) Main mold: A flat plate mold made of steel (S55C), the mold surface is mirror-like, and hard chrome plating is applied. (B) Polyimide precursor and cured polyimide: The linear high-molecular-weight polyimide precursor solution was trained with # 3.
00 (trade name, manufactured by Toray Industries, Inc.) was used. The performance of the cured polyimide is Tg of 300 ° C. and thermal conductivity of 0.000.
5 cal / cm · sec · ° C, breaking elongation 60%.

(C) Polyimide-coated mold: A polyimide precursor solution was applied to the main mold and heated to 160 ° C. for partial imidization, and then the above-mentioned coating and heating at 160 ° C. were repeated 10 times, and finally 290 ° C. It is heated up to 100% for imidization, and further, YP-9327 (trade name of Toshiba Silicon Co., Ltd.) containing polydiphenylsiloxane and bisphenol A epoxy resin as main components is applied on the surface of the polyimide, and at 150 ° C. After heat curing, a polymer thin film having a thickness of about 2 μm was mirror-coated. (D) Reinforced resin and unreinforced resin: Zylon X333V as a polyphenylene ether-based reinforced resin containing glass fiber and mica in a total amount of 30% by weight, Zylon 500V as an unreinforced resin (trade name of Asahi Kasei Kogyo Co., Ltd.), and polyacetal Tenac 4520 (a product name of Asahi Kasei Kogyo Co., Ltd.) as a reinforced resin, Stylac IM15 (a product name of Asahi Kase Kogyo Co., Ltd.) as an ABS unreinforced resin, P
Novalloy-S S5230 as C / ABS reinforced resin
(Trade name manufactured by Daicel Chemical Industries, Ltd.) and Panlite G-3130H (trade name manufactured by Teijin Chemicals Ltd.) were used as the PC resin.

[0052]

[Comparative Examples 1 to 3] Tests were conducted in the same manner as in Examples 1 to 3 except that a mold not coated with polyimide was used. The results are shown in Table 5. The obtained molded product had a large amount of protrusion of the reinforcing filler and the inorganic filler, poor surface smoothness, and poor sliding characteristics. In particular, the pins were heavily worn.

[0053]

[Table 5]

[0054]

EFFECTS OF THE INVENTION Conventionally, the problem of the reinforced resin CD-ROM mechanism parts, that is, the problem that the sliding portion is scraped off due to the rough surface due to the floating of the reinforcing filler and the inorganic filler, and the sliding, (EN) It is possible to provide a CD-ROM mechanical component having excellent sliding characteristics, in which the problem of rattling of the size of a part is solved.

Claims (1)

[Claims] 1. A reinforcing filler and / or an inorganic filler is used in an amount of 5 to 5.
The amorphous thermoplastic resin containing 50% by weight has a thermal conductivity of 0.0 at least on the mold wall surface forming the sliding portion among the mold wall surfaces constituting the mold cavity of the main mold made of metal.
A method for producing a CD-ROM mechanical component, which is injection-molded using a mold covered with a heat insulating layer made of a heat-resistant polymer having a thickness of 02 cal / cm · sec · ° C. or less to a thickness of 0.01 to 2 mm.