TW201342370A - Disc damper and hard drive - Google Patents

Abstract

The present invention provides a disc damper for suppressing disk vibration provided in a hard drive, which is molded from a resin composition containing a polyamide resin (A), glass fibers (B), an inorganic filling material (C), and a conductive filler (D), wherein a mass ratio Y/X of the content Y of the inorganic filling material (C) the content X of the glass fibers (B) in the resin composition is 2.5 or less.

Description

Disc damper and hard disk drive

The present invention relates to a disc damper and a hard disk drive.

In recent years, hard disk drives used in PCs and video recorders have been in progress. The hard disk drive system is constituted, for example, by a base that supports the entire hard disk drive, a disk of the recording portion, a spindle motor that rotates the disk of the recording portion, and an actuator that is mounted at the front end portion. magnetic head. Here, the head maintains a certain flying height from the disc and provides a portion for reading and writing magnetic recording.

Due to the high capacity of such a hard disk drive, it is necessary to reduce the distance between the magnetic head and the disk, but at this time, due to the rotation of the disk, wind is generated in the hard disk, and there is a possibility that vibration of the suspension supporting the magnetic head is generated. The situation. When the suspension vibrates, the stability of reading and writing by the magnetic head is impaired.

Further, in the hard disk, when the disk is rotated, there is a problem that the disk vibrates in the direction of the rotation axis, and the vibration is also detrimental to the stability of reading and writing.

Therefore, in recent years, in order to suppress the vibration of the suspension frame and the vibration of the disk, it has been attempted to attach a component called a disk damper to the hard disk (Patent Document 1).

Prior technical literature Patent literature

[Patent Document 1] Japanese Patent No. 3782754

The disc damper is required to have excellent mechanical strength and less warpage. Further, in order to prevent static electricity, it is required to have excellent conductivity. In general, it is difficult for the resin composition to sufficiently satisfy these necessary conditions, and therefore, it is difficult to use a resin composition instead of the disc damper.

An object of the present invention is to provide a disk damper and a hard disk drive including the disk damper that consumes power and has a low rate of occurrence, wherein the disk damper is formed of a resin composition and has sufficient Mechanical strength and electrical conductivity, and less warpage and excellent productivity.

The inventors of the present invention have devoted themselves to research and development in order to solve the above problems. As a result, it has been found that the present invention can be solved by solving the above problems by using a specific resin composition.

That is, a first aspect of the present invention relates to a disc damper for suppressing a disk vibrator disposed in a hard disk drive, the disc damper comprising a polyamide resin (A), A resin composition of the glass fiber (B), the inorganic filler (C), and the conductive filler (D), wherein the content Y of the inorganic filler (C) in the resin composition is relative to the glass The mass ratio Y/X of the content X of the fiber (B) is 2.5 or less.

Since the disc damper is formed by molding a specific resin composition, it has excellent mechanical strength and can sufficiently suppress warpage deformation. Moreover, since the above disc damper is formed by molding a specific resin composition, it is excellent in electrical conductivity. It is good enough to suppress the generation of static electricity in the hard disk drive. Further, when such a disc damper is used, it is possible to realize a hard disk drive that consumes less power and has a lower rate of occurrence.

In one aspect of the invention, the inorganic filler (C) is an inorganic filler having an average aspect ratio of 1.0 to 100. When such an inorganic filler is used, the effects of the present invention can be more significantly achieved.

In one aspect of the invention, the conductive filler (D) is conductive carbon. When such a conductive filler is used, the effects of the present invention can be more significantly achieved.

In one aspect of the invention, the disc damper has a plate portion that is disposed on a surface of the disc of the magnetic disk and is disposed apart from the surface of the disc.

The thickness of the above plate portion may be 2 mm or less. In this aspect, since the disc damper is formed by molding the above-described specific resin composition, even if the thickness of the plate portion is 2 mm or less, excellent mechanical strength and warpage deformation can be sufficiently suppressed.

The surface resistivity of the above-mentioned plate portion is preferably 1 × 10 ² to 1 × 10 ⁹ Ω. Thereby, the generation of static electricity in the hard disk drive can be sufficiently suppressed.

The surface roughness of the above-mentioned plate portion is preferably 50 μm or less. Thereby, it is possible to more significantly suppress the occurrence of vibration of the disk in the hard disk drive. The reason for this is considered to be that it is possible to more effectively rectify the wind generated in the hard disk when a plate portion having a surface roughness of 50 μm or less is used.

In one aspect of the invention, the disc damper preferably has an amount of exhaust gas of 15,000 ng/g or less at 85 ° C for 5 hours. Thereby, it is possible to achieve an effect of reducing the rate of occurrence of defects due to the occurrence of a gas-contaminated recording surface.

In one aspect of the invention, the inorganic filler (C) is selected from the group consisting of wollastonite, mica, kaolin, talc, glass cullet, glass beads, and glass. Inorganic fillers in groups of balloons. When such an inorganic filler is used, the effect of the present invention can be more remarkably achieved by satisfying the above-described mass ratio.

In one aspect of the invention, the total amount of the glass fiber (B) and the inorganic filler (C) in the resin composition is 40% by mass or more based on the total amount of the resin composition. Preferably, it can be 45 mass% or more. Thereby, in the disc damper, excellent mechanical strength is obtained, and at the same time, the effect of sufficiently suppressing warpage can be achieved.

In one aspect of the invention, the mass ratio Y/X is preferably from 0.2 to 1.5. By setting the mass ratio Y/X within this range, the effects of the present invention can be more significantly achieved.

In one aspect of the invention, the polyamine resin (A) may be at least one selected from the group consisting of an aliphatic polyamine resin, an alicyclic polyamide resin, and a semi-aromatic polyamide resin. 1 species. When such a polyamide resin is used, the desired characteristics as the above-described disc damper can be more easily obtained.

In one aspect of the invention, the polyamine resin (A) may be a unit having a hexamethylene adipamide unit and a hexamethylene isonamide unit. When such a polyamide resin is used, the desired characteristics as the above-described disc damper can be more easily obtained.

In one aspect of the invention, the resin composition contains 50 to 150 parts by mass of the glass fiber (B), and 10 to 40 parts by mass of the above inorganic filler based on 100 parts by mass of the polyamide resin (A). The material (C) and 5 to 20 parts by mass of the above conductive filler (D) are preferred. When a resin composition containing each component is used in such a content, a disc damper which achieves the above effects more remarkably can be obtained.

In one aspect of the invention, the above polyamido resin (A) can be based on JIS K 6810 and a polyimide resin having a relative viscosity (η r) of 1.5 to 4.5 as measured under conditions of a concentration of 1% and 25 ° C in 96% sulfuric acid. When such a polyamide resin is used, the disc damper has excellent mechanical strength, and at the same time, the resin composition can achieve the effect of sufficiently ensuring the fluidity of the preferable injection molding.

In one aspect of the invention, the inorganic filler (C) is preferably calcined kaolin or ash. When such an inorganic filler is used, the resin composition and the molded article thereof are more excellent in thermal stability.

In one aspect of the invention, the conductive filler (D) may be a conductive carbon having a dibutyl phthalate oil absorption of 250 mL/g or more. When such a conductive filler is used, excellent conductivity can be imparted by a small amount of blending.

In one aspect of the invention, the conductive filler (D) does not contain carbon fibers. The disc damper described above can obtain the above-described excellent effects even without using carbon fibers as the conductive filler (D).

A second aspect of the invention relates to a hard disk drive comprising a magnetic disk and the disk damper, wherein the disk damper has a plate portion attached to a disk surface of the magnetic disk , configured to be isolated from the surface of the disc. When such a hard disk drive is used, the disk vibration can be effectively suppressed by the disk damper, and power consumption can be reduced and the rate of occurrence of defects can be reduced.

In one aspect of the invention, 10 to 75% of the total area of the disc surface is covered by the plate portion. Thereby, the vibration of the magnetic disk can be suppressed more remarkably.

According to the present invention, it is possible to obtain a disk damper which is formed of a resin composition and has a sufficient mechanical mechanism, and a disk damper which is provided with a power consumption and a poor rate of occurrence. Strength and electrical conductivity, Moreover, the warpage deformation is small and the productivity is excellent.

1‧‧‧ disc damper

2‧‧‧Disk

3‧‧‧Spindle motor

4‧‧‧Actuator

11‧‧‧ Board Department

12‧‧‧ Fixed Department

41‧‧‧ head

100‧‧‧ hard disk drive

Fig. 1 is a schematic view showing a disc damper of the embodiment.

Fig. 2 is a view showing the hard disk drive of the embodiment.

[Formation for implementing the invention]

Hereinafter, the form for carrying out the invention (hereinafter also referred to as "this embodiment") will be described in detail. In addition, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

The disc damper according to the present embodiment is formed by molding a resin composition containing a polyamide resin (A), a glass fiber (B), an inorganic filler (C), and a conductive filler (D). The mass ratio Y/X of the content Y of the inorganic filler (C) of the composition to the content X of the glass fiber (B) is 2.5 or less.

The disc damper of the present embodiment has a plate portion that is disposed apart from the disc surface on the disc surface of the disc.

The thickness of the plate portion is preferably 2 mm or less. Further, the surface resistivity of the plate portion is preferably from 1 × 10 ² to 1 × 10 ⁹ Ω. Further, the surface roughness of the plate portion is preferably 50 μm or less.

In the disk damper of the present embodiment, the resin composition is molded, and even if the thickness of the plate portion is 2 mm or less, the mechanical strength is excellent and warpage can be sufficiently suppressed. Further, in the disk damper of the present embodiment, the resin composition is molded, and the surface resistivity in the plate portion can be easily made excellent in electrical conductivity of 1 × 10 ² to 1 × 10 ⁹ Ω. Moreover, the surface roughness of 50 μm or less can be easily achieved.

Hereinafter, each component of the resin composition of the present embodiment will be described in detail.

[Polyuramine resin (A)]

The polyamine resin (A) may be a resin having a plurality of guanamine bonds, and as the polyamine resin (A), a well-known polyamine resin can be used. As the polyamine resin (A), only one type of polyamine resin may be used, or two or more types of polyamine resin may be used in combination.

Examples of the polyamine resin (A) include a polyamidamide resin synthesized by ring-opening polymerization of indoleamine, and a polydecylamine synthesized by a copolycondensation reaction of a diamine and a dicarboxylic acid. Resin. Among these, the polyamide resin (A) is preferably a polyamine resin synthesized by a copolycondensation reaction of a diamine and a dicarboxylic acid from the viewpoint of remarkably suppressing generation of exhaust gas.

In the present embodiment, the polyamide resin (A) is preferably at least one selected from the group consisting of an aliphatic polyamine resin, an alicyclic polyamide resin, and a semi-aromatic polyamide resin.

Examples of the aliphatic polyamine resin include a polyamidamide resin synthesized by ring-opening polymerization of an indoleamine; and a polycondensation synthesized by a copolycondensation reaction of an aliphatic diamine and an aliphatic dicarboxylic acid. Amidoxime resin, etc.

Specific examples of the aliphatic polyamine resin include polyamido 66 (a polyamine resin synthesized by a copolycondensation reaction of hexamethylenediamine and adipic acid), and polyamine 6 (by ε-hexyl) Polyamide amine synthesized by ring-opening polycondensation reaction of indoleamine, polyamine 46 (polyamide resin synthesized by copolycondensation reaction of butane and adipic acid), polyamine 610 (hexamethylenediamine) Polyamide resin synthesized by copolycondensation reaction with sebacic acid), poly Indoleamine 11 (polyamide resin synthesized by ring-opening polycondensation reaction of undecyl indoleamine), polydecylamine 12 (polyamide resin synthesized by ring-opening polycondensation reaction of laurylamine), polydecylamine 612 (polyamide resin synthesized by ring-opening copolycondensation reaction of oleic acid with caprolactam and omega amino acid), polyamine 6/66 (made hexamethylenediamine, adipic acid and ε-) Polyamide resin obtained by copolycondensation of caprolactam), polyamine 6/612 (polyamide resin obtained by co-condensation of ε-caprolactam, caprolactam and laurylamine) .

The alicyclic polyamine resin is a polyamine resin having a plurality of alicyclic structures, and examples of the alicyclic polyamine resin include a diamine component and a dicarboxylic acid component containing an alicyclic diamine. a polyamine resin synthesized by a copolycondensation reaction; and a polyamidamide resin synthesized by a copolycondensation reaction of a diamine component and a dicarboxylic acid component containing an alicyclic dicarboxylic acid. Among these, as the alicyclic polyamine resin, a polyamine resin synthesized by a copolycondensation reaction of a diamine component and a dicarboxylic acid component containing an alicyclic dicarboxylic acid is preferable.

The alicyclic dicarboxylic acid has an alicyclic structure having a carbon number of preferably 3 to 10 and preferably 5 to 10.

The alicyclic structure of the alicyclic dicarboxylic acid may have a substituent other than a carboxyl group. The substituent may, for example, be an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a t-butyl group.

Specific examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,3-cyclopentanedicarboxylic acid.

The alicyclic dicarboxylic acid has a geometrical isomer of a cis isomer or a trans isomer, and the alicyclic dicarboxylic acid as a raw material monomer can be either a cis isomer or a trans form, and can also be used. Use a mixture of the two.

Compared with the trans-body, the cis-form of the alicyclic dicarboxylic acid and the diamine The water solubility of the salt has a high tendency. Therefore, as the raw material monomer dicarboxylic acid, the molar ratio of the cis isomer to the trans isomer (cis to trans/body ratio) is preferably 50/50 to 0/100, and 40/60 to 10/90 is preferred, and more preferably 35/65 to 15/85.

Here, the molar ratio (the ratio of the cis isomer/trans isomer) can be determined by high performance liquid chromatography (HPLC), gas chromatography (GC), NMR, or the like. For example, in the case of NMR, 30 to 40 mg of a polyamide resin was dissolved in 1.2 g of hexafluoroisopropoxide oxime and measured using ¹ H-NMR. The cis-form/trans-form can be obtained from the ratio of the peak area of the peak derived from the trans isomer in the obtained ¹ H-NMR spectrum to the peak area derived from the peak of the cis isomer. ratio. For example, in the case of 1,4-cyclohexanedicarboxylic acid, the ratio of the peak area of 1.98 ppm derived from the trans isomer to the peak area of 1.77 ppm and 1.86 ppm derived from the cis isomer can be determined. The ratio of the body to the trans body.

The alicyclic dicarboxylic acid is a 1,4-cyclohexanedicarboxylic acid from the viewpoint of heat resistance, fluidity, and rigidity of the obtained alicyclic polyamide resin becoming a more desirable damper plate user. It is better.

From the viewpoint of the toughness and chemical resistance of the obtained alicyclic polyamine resin, the 1,4-cyclohexanedicarboxylic acid becomes a more desirable damper plate user, and the ratio of the cis-form/trans-body is The ear ratio is preferably 50/50 or more. Further, from the viewpoint that the molded article of the obtained alicyclic polyamine resin is more excellent in appearance, the ratio of the cis isomer/trans is preferably 97/3 or less. The cis/trans isomer ratio (mol ratio) of 1,4-cyclohexanedicarboxylic acid is preferably from 50/50 to 90/10, more preferably from 55/45 to 90/10. Good is 70/30 to 90/10.

In the copolycondensation reaction for obtaining an alicyclic polyamine resin, the heat resistance, chemical resistance, light resistance and weather resistance of the alicyclic polyamine resin are more rational. From the viewpoint of the damper plate user, the amount of 1,4-cyclohexanedicarboxylic acid is preferably 10 mol% or more based on the total amount of the dicarboxylic acid component, and is formed from the alicyclic polyamine resin. The viewpoint that the appearance of the article and the molded article is better is preferably 80 mol% or less. The amount of 1,4-cyclohexanedicarboxylic acid is preferably from 10 to 70 mol%, more preferably from 10 to 60 mol%, based on the total amount of the dicarboxylic acid component.

Examples of the component other than 1,4-cyclohexanedicarboxylic acid in the dicarboxylic acid component include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, and 2- Methyl adipate, trimethyl adipate, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethyl succinic acid, sebacic acid, sebacic acid, suberic acid An aliphatic dicarboxylic acid such as dodecanedioic acid or eicosane dibasic acid; 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexane Fats such as dicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cycloheptane dicarboxylic acid, 1,3-cycloheptane dicarboxylic acid, 1,4-cycloheptane dicarboxylic acid Cyclodicarboxylic acid; citric acid, isodecanoic acid, naphthalene dicarboxylic acid, 2-chloro-p-decanoic acid, 2-methyl-p-decanoic acid, 5-methylisodecanoic acid, isophthalic acid-5-sulfonate An aromatic dicarboxylic acid such as sodium salt; diglycolic acid or the like. These may be used alone or in combination of two or more. Further, in the synthesis of the alicyclic polyamine resin, in addition to the diamine component and the dicarboxylic acid component, 1,2,4-benzenetricarboxylic acid, 1, may be further used without departing from the object of the present invention. A trivalent or higher polycarboxylic acid such as 3,5-benzenetricarboxylic acid or trimellitic acid.

a component other than 1,4-cyclohexanedicarboxylic acid in the dicarboxylic acid component, a dicarboxylic acid selected from the group consisting of aliphatic dicarboxylic acids having 6 to 12 carbon atoms and aromatic dicarboxylic acids. Ideally, adipic acid and isophthalic acid are more desirable.

The dicarboxylic acid component preferably contains 10 to 60 mol% of 1,4-cyclohexanedicarboxylic acid, 20 to 90 mol% of adipic acid, and 0 to 40 mol% of isophthalic acid. When the total amount of 1,4-cyclohexanedicarboxylic acid, adipic acid, and isononanoic acid is 100 mol% Better.

Further, the content of each carboxylic acid unit in the alicyclic polyamine resin can be determined, for example, by gas chromatography (GC). Specifically, the alicyclic polyamine resin is hydrolyzed by using hydrobromic acid (HBr) or the like, and then the carboxylic acid is subjected to trimethylsulfonylation and the GC is measured, thereby obtaining the peak derived from each dicarboxylic acid. The peak area is determined by the content of each dicarboxylic acid unit.

In the alicyclic polyamine resin, a diamine component which is polycondensed and polymerized with a dicarboxylic acid component containing an alicyclic dicarboxylic acid is preferably an aliphatic diamine.

Examples of the aliphatic diamine include ethylenediamine, propylenediamine, butanediamine, heptanediamine, hexamethylenediamine, pentamethylenediamine, octanediamine, decanediamine, decanediamine, and undecane Amine, dodecanediamine, 2-methylpentanediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexanediamine, 5-methylnonanediamine, 2,4-Dimethyloctanediamine, 5-methylnonanediamine. The aliphatic diamines may be used singly or in combination of two or more. Further, in the synthesis of the alicyclic polyamine resin, the scope of the object of the present invention is not impaired except for the diamine component and the dicarboxylic acid component. Further, a trivalent or higher polydiamine component such as bis-hexamethylenetriamine may be further used.

As the aliphatic diamine, an aliphatic diamine having 4 to 12 carbon atoms is preferred, and an aliphatic diamine having 6 to 8 carbon atoms is more preferred, and hexamethylenediamine and 2-methylpentanediamine are preferred. good.

In the synthesis of the alicyclic polyamine resin, in addition to the dicarboxylic acid component and the diamine component, an amino acid capable of being condensed with the above, or a decylamine may be used as a copolymerization component. Examples of the amino acid include 6-aminohexanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and p-aminomethylbenzoic acid. Further, examples of the indoleamine include butyrolactam, valeroinamide, caprolactam, caprysamine, and heptamidine. Undecane indoleamine, dodecane indoleamine, and the like. These may be used alone or in combination of two or more.

Examples of the semi-aromatic polyamide resin include a polyamine resin synthesized by a copolycondensation reaction between a diamine component containing an aromatic diamine and a dicarboxylic acid component containing an aliphatic dicarboxylic acid; and a fat containing A polyamine resin synthesized by a copolycondensation reaction of a diamine component of a diamine and a dicarboxylic acid component containing an aromatic dicarboxylic acid.

Examples of the semi-aromatic polyamine resin include polydecylamine MXD6 (a polydecylamine resin synthesized by a copolycondensation reaction of m-xylene diamine and adipic acid), and polyamine 6T (hexamethylenediamine and a pair). Polyamide resin synthesized by polyamine resin synthesized by copolycondensation reaction of citric acid, polyamine 6I (polyamide resin synthesized by copolycondensation reaction of hexamethylenediamine and isononic acid), polyamine Binary copolymer of PACMI (polyamide resin synthesized by copolycondensation reaction of isophthalic acid with bis(3-methyl-4aminocyclohexyl)methane); polyamido 66/6I copolymer Polydecylamine resin obtained by copolycondensation of acid, isophthalic acid and hexamethylenediamine), polyamido 66/6I/6 copolymer (adipate, isodecanoic acid, hexamethylene diamine and ε-caprolactam) Polycondensation of polyamine resin), polyamine 66/6T copolymer (polyamide resin obtained by copolycondensation of adipic acid, p-citric acid and hexamethylene diamine), polyamido 6I/6T copolymer ( Polydecylamine resin obtained by copolycondensation of isophthalic acid, citric acid and hexamethylenediamine), polyamido 66/6I/6T copolymer (adipate, isononanoic acid, p-nonanoic acid and hexamethylene diamine) Polyamide resin), polyamine 6/6T (p-citric acid, Polyamide resin obtained by copolycondensation of diamine and ε-caprolactam), polyamido resin compounded by polyamido 6/6I (isodecanoic acid, hexamethylenediamine and ε-caprolactam) ), polyamine 66/6T (polyamide resin obtained by copolycondensation of adipic acid, p-nonanthanic acid and hexamethylene diamine), polyamido 66/6I (adipate, isononanoic acid and hexamethylene diamine) Polycondensation of polyamine resin), polyamine 6T/6I (isodecanoic acid, polydecylamine resin obtained by copolycondensation of decanoic acid and hexamethylenediamine), polyamine 6/6T/6I (isoindole) Acid, citric acid, hexa Polyamine resin obtained by co-condensation of amine and ε-caprolactam), polyfluorene 6/12/6T (ε-caprolactam, laurylamine, p-nonanoic acid and hexamethylene diamine) Polyamide resin), polyamine 66/12/6T (polyamide resin formed by co-condensation of laurylamine, adipic acid, p-nonanthanic acid and hexamethylenediamine), polyamine 6/12 /6I (polyamide resin obtained by co-condensation of laurylamine, ε-caprolactam, isodecanoic acid and hexamethylenediamine), polyamido 66/12/6I (lauric acid, adipic acid , polydecylamine resin obtained by copolycondensation of isophthalic acid and hexamethylenediamine), polyamidamine 9T (polyamide resin obtained by copolycondensation of decanoic acid and decane diamine), polythramine TMDT copolymer (pair) Tannic acid, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine and polycondensed polyamine resin), and isononanoic acid, citric acid, A polyamine resin obtained by copolycondensation of a diamine and bis(3-methyl-4aminocyclohexyl)methane.

Further, as the polyamine resin (A), a polyamidamide resin obtained by copolycondensation of isophthalic acid, p-citric acid, hexamethylenediamine, and bis(3-methyl-4-aminocyclohexyl)methane can also be used. A mixture with polyamine 6 and a mixture of polyamide MXD6 and polyamide 66.

In the present embodiment, the polyamine resin (A) may be used singly or in combination of two or more. Further, it is also possible to use a polyamide resin in which two or more kinds of the above polyamine resins are further copolymerized by an extruder or the like.

The polyamide resin (A) is a polyamine containing a hexamethylene hexamethyleneamine unit (hereinafter also referred to as "N66") and a hexamethyleneisodecylamine unit (hereinafter also referred to as "N6I"). Resin (hereinafter also referred to as "polyamide resin (a)") is preferred. Here, N66 is a structural unit formed by a condensation reaction of hexamethylenediamine and adipic acid, and N6I is a structural unit formed by a condensation reaction of hexamethylenediamine and isononanoic acid.

Polyamine resin (a) can be a polyamine tree composed of N66 and N6I The fat may be a polyamide resin further having a structural unit other than N66 and N6I. Examples of the structural unit other than N66 and N6I include a polycapramide unit (hereinafter also referred to as "N6"). N6 is a structural unit formed by a ring opening reaction of caprolactam.

Further, in the present embodiment, among the polyamine resins (a), a copolymer composed of N66 and N6I is referred to as "polyamido 66/6I copolymer", and is composed of N66, N6I and N6. The copolymer formed is a case called "polyamide 66/6I/6 copolymer". The polyamide resin (A) is preferably at least one selected from the group consisting of polyamine 66/6I copolymer and polyamine 66/6I/6 copolymer.

A preferred example of the polyamine resin (a) is a polyamine resin having 70 to 83% by mass of N66 and 17 to 30% by mass of N6I based on the total amount of N66 and N6I.

Further, as the polyamine resin (a), for example, 70 to 83% by mass of N66 and 17 to 30% by mass of N6I can be used as a reference, and the total amount of N66 and N6I is also used. 100 parts by mass, having 1 to 10 parts by mass of N6 polyamine resin.

The content of N6I in the polyamide resin (a) is preferably from 17 to 30% by mass, more preferably from 20 to 29% by mass, even more preferably from 23 to 28% by mass, based on the total amount of N66 and N6I. good. When the content of N6I is in the above range, the warpage deformation of the disc damper can be more significantly suppressed, and the smoothness of the disc damper can be improved. In addition, by using the polyamide resin (a) having a content of N6I in the above range, the elongation at the time of melting of the resin composition can be improved, and the productivity can be further improved.

When the polyamide resin (a) contains N6, the content of N6 is preferably from 1 to 10 parts by mass, preferably from 3 to 7 times, per 100 parts by mass of the total of N66 and N6I. The amount is more preferably 4 to 6 parts by mass. When the content of N6 is in the above range, the toughness of the resin composition can be remarkably excellent.

Preferable examples of the polyamine 66/6I copolymer include a copolymer of N66 and 5 to 40% by mass of N6I in an amount of 60 to 95% by mass based on the total amount of the copolymer. When such a polyamide 66/6I copolymer is used, the generation of exhaust gas can be further reduced.

In the above polyamine 66/6I copolymer, the content of N66 is preferably from 63 to 90% by mass, more preferably from 65 to 85% by mass, still more preferably from 70 to 83% by mass. Further, the content of N6I is preferably from 10 to 37% by mass, more preferably from 15 to 35% by mass, still more preferably from 17 to 30% by mass. When a copolymer satisfying such a content range is used, the warpage deformation of the disc damper can be more significantly suppressed, and the smoothness of the disc damper can be further improved.

Preferable examples of the polyamine 66/6I/6 copolymer include N66, 5 to 35 mass% of N6I, and 1 to 10 mass% of 55 to 95 mass% based on the total amount of the copolymer. Copolymer of N6. When such a polyamide 66/6I/6 copolymer is used, the warpage of the disc damper can be more significantly suppressed, and the smoothness of the disc damper can be improved.

In the above polyamine 66/6I/6 copolymer, the content of N66 is preferably from 60 to 90% by mass, more preferably from 65 to 85% by mass. Further, the content of N6I is preferably from 7 to 32% by mass, more preferably from 10 to 30% by mass. Further, the content of N6 is preferably from 1 to 8% by mass, more preferably from 1 to 5% by mass. When a copolymer satisfying such a content range is used, the warpage deformation of the disc damper can be more significantly suppressed, and the smoothness of the disc damper can be further improved.

Polyamide resin (A) is based on JIS K 6810 and uses 96% sulfuric acid The relative viscosity (η r) (also referred to as "sulfuric acid relative viscosity") measured at a medium concentration of 1% and 25 ° C is preferably 1.5 to 4.5, preferably 1.7 to 4.3, and 1.9 to 4.1. Better. Further, when the polyamide resin (A) is a polyamide-6/6I copolymer, the relative viscosity (?r) is preferably from 1.8 to 2.5. When a polyamide resin having a relative viscosity (η r) in the above range is used, the appearance and smoothness of the resin composition after molding can be further improved.

Further, the relative viscosity (η r) of the polyamide resin can be adjusted, for example, by adjusting the polymerization time and in an appropriate range.

[glass fiber (B)]

In the present embodiment, the glass fiber (B) is blended in order to impart excellent mechanical strength, rigidity, and formability to the resin composition. The glass fiber (B) is not particularly limited, and can be used, for example, in a polyamide resin. As the glass fiber (B), a strand, a roving, a ground fiber, or the like can be used.

The average fiber diameter of the glass fiber (B) is not limited to the following, and can be, for example, 5 to 30 μm or 7 to 20 μm.

The average fiber length of the glass fiber (B) is not limited to the following, and for example, when dicing is used, it may be appropriately selected in the range of 0.1 to 6 mm.

Further, in the present specification, the average fiber diameter and the average fiber length are the average values of the values obtained by measuring the diameter and length of the 500 fibers which are randomly extracted.

The average aspect ratio (average fiber length / average fiber diameter) of the glass fiber (B) can be, for example, 200 or more, or 250 or more. Further, depending on the case, it is preferably 700 or less, and may be 500 or less. When the average aspect ratio of the glass fiber (B) is 200 or more, the mechanical strength of the molded article tends to be further improved. When the average aspect ratio is 700 or less, the formability of the resin composition is more favorable. to.

As the glass fiber (B), a sizing agent and a decane coupling agent can be applied to the surface. The sizing agent is not particularly limited, and a previously known sizing agent can be used. Further, the decane coupling agent is not particularly limited, and for example, γ-aminopropyltrimethoxydecane, γ-aminopropyltriethoxydecane, and N-β(aminoethyl)-γ-aminopropyltrimethyl can be used. Oxydecane, vinyl triethoxysilane, γ-glycidoxypropyltrimethoxydecane, and the like.

[Inorganic filler (C)]

In the present embodiment, the resin composition is capable of suppressing warpage deformation of the disk damper of the molded article of the resin composition by containing the inorganic filler (C). Further, in the present embodiment, the inorganic filler (C) is in the form of a pellet or a block, and in this respect, it can be clearly distinguished from the glass fiber (B).

In order to further suppress warpage deformation, the inorganic filler (C) preferably has an average aspect ratio of 1.0 to 100, preferably 1.0 to 50, more preferably 1.0 to 20.

In addition, the average aspect ratio of the inorganic filler (C) in the resin composition can be obtained by burning a resin component of the resin composition in an electric furnace at 50 ° C, and then using a scanning electron microscope (SEM) at a magnification of from 1,000 to 50,000. The particle image of the inorganic filler (C) was taken at a time, and the long diameter and the short diameter of each of the 200 inorganic filler (C) particles selected were measured.

In the present embodiment, the longest axis length of the particle image of the inorganic filler (C) is defined as the long diameter (particle diameter), and the shortest axis length of the particle image is defined as the short diameter. Further, the average particle diameter, the average major axis, the average minor axis, and the average aspect ratio can be obtained by the following formula.

Average long diameter = average particle diameter = Σ (Li2) / Σ Li

Average short diameter = Σ (Di2) / Σ Di

Average aspect ratio L/D=[Σ(Li2)/Σ Li]/[Σ(Di2)/Σ Di](The long diameters (particle sizes) of the particles are set as L1, L2, ..., L200, respectively. The short diameters are respectively set as D1, D2, ..., D200. In the formula, i is an integer of 1 to 200).

As the inorganic filler (C), a mineral filler and a glass filler can be applied. As a mineral filler, it is preferable to use limestone, mica, kaolin, and talc. As a glass filler, it is preferable to use glass chips, glass beads, and glass balloons.

That is, as the inorganic filler (C), for example, at least one selected from the group consisting of a limestone, a mica, a kaolin, a talc, a glass bead, and a glass balloon is preferably used. By using these as the inorganic filler (C), the warpage deformation of the resin composition can be further reduced.

The ash stone is a mineral with a chemical name called calcium citrate and white needle crystal. The asbestos usually contains 40 to 60% by mass of SiO ₂ and contains 40 to 55% by mass of CaO, and further contains a component such as Fe ₂ O ₃ , Al ₂ O ₃ , MgO, Na ₂ O, K ₂ O or the like.

The average fiber diameter of the ascites is preferably from 0.5 to 20 μm, preferably from 1.0 to 15 μm, more preferably from 2.0 to 10 μm.

Mica, also known as mica, is a crystalline structure of a layered silicate mineral with a potassium atom and an aluminum atom sandwiched between layers of tannic acid tetrahedron. As a type of mica, there are naturally muscovite, phlogopite and sericite, especially muscovite which can be applied in white tones. The chemical composition of mica is usually composed of 35 to 50% by mass of SiO ₂ , 10 to 40% by mass of Al ₂ O ₃ , and 5 to 10% by mass of K ₂ O, and also contains MgO, Fe ₂ O ₃ , and H _{2 .} O, F, Na ₂ O, CaO as other impurities.

As the average particle diameter of mica, it is preferably 30 to 300 μm, preferably It is 35 to 250 μm, more preferably 40 to 200 μm.

Kaolin is an aluminum citrate salt which is usually used by dehydrating crystal water by calcination. The chemical composition of kaolin is 40 to 50% by mass of Al ₂ O ₃ and 50 to 60% by mass of SiO ₂ , and most of them also contain Na ₂ O, TiO ₂ , CaO, Fe ₂ O ₃ , MgO, K _{2 .} O and other impurities. Among the kaolin, calcined kaolin is preferred from the viewpoint that the appearance of the molded article of the resin composition is good.

The average particle diameter of the kaolin is preferably from 0.5 to 10 μm, preferably from 1.0 to 8.0 μm, more preferably from 2.0 to 6.0 μm.

Talc and mica are layered silicates, which are white powder-like crystal minerals having a magnesium oxide octahedral structure between layers of tannic acid tetrahedron. The chemical composition of talc contains 60 to 70% by mass of SiO ₂ and 30 to 40% by mass of MgO, and most of the cases also contain impurities such as Al ₂ O ₃ , Fe ₂ O ₃ , CaO and the like.

The average particle diameter of the talc is preferably from 0.5 to 30 μm, preferably from 1.0 to 25 μm, more preferably from 2.0 to 20 μm.

The average particle diameter of the glass cullet, the glass beads and the glass balloon is preferably 5 to 50 μm, preferably 10 to 45 μm, more preferably 15 to 40 μm.

[conductive filler (D)]

Examples of the conductive filler (D) include conductive carbon, carbon fiber, graphite, fine metal powder (silver, copper, nickel, etc.), metal oxide (zinc oxide, tin oxide, etc.), and metal fiber (aluminum, stainless steel). and many more. Further, the conductive carbon means carbon black of a ochre micropowder produced by incomplete combustion of natural gas or liquid hydrocarbon.

As the conductive filler (D), it is preferable to use a conductive filler other than carbon fibers from the viewpoint of suppressing defects caused by dropping or the like, and it is possible to obtain particularly desirable conductivity and other physical properties from the disc damper. Opinion so that Conductive carbon is preferred.

The conductive carbon is not limited to the following, and acetylene black obtained by completely burning acetylene gas and KETJEN BLACK obtained by furnace incomplete combustion using crude oil as a raw material are preferred. .

From the viewpoint of obtaining remarkably high conductivity, the amount of dibutyl phthalate (DBP) absorbed by the conductive carbon is preferably 250 mL/100 mg or more, preferably 300 mL/100 g or more, more preferably 350 to 600 mL/100 g. Further, the DBP oil absorption amount is a value measured in accordance with the method specified in ASTM D2414.

[Resin composition]

The resin composition contains a polyamide resin (A), a glass fiber (B), an inorganic filler (C), and a conductive filler (D).

The content of the polyamide resin (A) in the resin composition is preferably 30 to 70% by mass, preferably 40 to 60% by mass, and 40 to 50% by mass based on the total amount of the resin composition. For better.

The content of the glass fiber (B) in the resin composition is more excellent in rigidity from the resin composition, and is preferably 50 parts by mass or more based on 100 parts by mass of the total amount of the polyamide resin (A). The mass portion or more is more preferably 80 parts by mass or more. In addition, the content of the glass fiber (B) is preferably 150 parts by mass or less, more preferably 140 parts by mass or less, from the viewpoint of further improving the fluidity of the resin composition at the time of the composite and the injection molding. The following parts are better.

The content of the inorganic filler (C) in the resin composition is 10 parts by mass or more based on 100 parts by mass of the total amount of the polyamide resin (A) from the viewpoint of further suppressing the warpage deformation of the disk damper. Preferably, it is preferably 12 parts by mass or more, more preferably 15 parts by mass or more. Further, the content of the inorganic filler (C) is from the resin composition The viewpoint of better mechanical strength and rigidity is preferably 40 parts by mass or less, more preferably 38 parts by mass or less, and still more preferably 35 parts by mass or less.

The content of the conductive filler (D) in the resin composition is preferably 5 parts by mass or more, and 7 parts by mass, based on 100 parts by mass of the total amount of the polyamide resin (A), from the viewpoint of more excellent conductivity. The above is preferred, and more preferably 8 parts by mass or more. In addition, the content of the conductive filler (D) is more preferably 20% by mass or less, more preferably 18 parts by mass or less, even more preferably 15 parts by mass or less, from the viewpoint of fluidity at the time of injection molding of the resin composition. good.

The total amount of the glass fiber (B) and the inorganic filler (C) in the resin composition is preferably 40% by mass or more, and more preferably 45% by mass or more based on the total amount of the resin composition. In addition, when the polyamide resin (A) of the present embodiment is substituted with a thermoplastic resin other than the polyamide resin, when the resin composition contains 40% by mass or more of the glass fiber (B) and the inorganic filler (C) It is difficult to obtain sufficient formability. On the other hand, in the present embodiment, when the polyamide resin (A) is present, even when the glass fiber (B) and the inorganic filler (C) are contained in an amount of 40% by mass or more in the resin composition, With sufficient formability, a remarkable effect of the present invention can be achieved.

The total amount of the glass fiber (B) and the inorganic filler (C) in the resin composition can be 70% by mass or less, or 60% by mass or less from the viewpoint of obtaining sufficient moldability.

Further, when the polyamide resin (A) is a polyamine resin (polyamide resin (a)) having N66 and N6I, the total of the glass fiber (B) and the inorganic filler (C) in the resin composition The amount is preferably 45% by mass or more based on the total amount of the resin composition. When the polyamide resin (A) is a polyamide resin (a), even if it contains 45 mass% or more of the glass fiber (B) and the inorganic filler (C), excellent molding can be obtained. Sex. Therefore, when such a resin composition is used, the effects of the present invention can be more remarkably achieved.

In addition, when the polyamide resin (A) is a polyamide resin (a), the total amount of the glass fiber (B) and the inorganic filler (C) in the resin composition can be obtained from the viewpoint of obtaining sufficient moldability. The amount is 75 mass% or less, and may be 65 mass% or less.

In the resin composition, the mass ratio Y of the content Y of the inorganic filler (C) to the content X of the glass fiber (B) is not more than 2.5, more preferably from 0.1 to 1.5, still more preferably from 0.2 to 1.5. When the mass ratio Y/X is more than 2.5, sufficient mechanical strength cannot be obtained. Further, when the mass ratio Y/X is from 0.1 to 1.5, the mechanical strength and surface resistivity of the disc damper are better.

The resin composition may be added with an antioxidant, a UV absorber, a thermal stabilizer, a photo-deterioration inhibitor, a plasticizer, and a lubricant which can be generally added to the resin composition as needed within the scope of the object of the present embodiment. Additives such as agents, mold release agents, nucleating agents, flame retardants, and the like.

[Method for Producing Resin Composition]

The resin composition of the present embodiment can be produced by mixing and kneading the above-mentioned components (A) to (D) and various additives as required.

In this case, the mixing, mixing and kneading methods, and the order of the processes are not particularly limited, and are generally used in a mixer such as a Henschel mixer, a tumbler or a ribbon mixer (Ribbon). Blender) and so on. As a kneader, a single or twin screw extruder is generally used. The mixing of the components can be mixed simultaneously or in sequence, and some components such as glass fibers can be melted. Side feed is performed during mixing.

Moreover, it is also possible to mix some of the components by another step, and then It is mixed with other ingredients, melted and pelletized.

In particular, in the case of the conductive filler (D), it is preferable to use a higher concentration of the polyamide resin (A) and the conductive filler (D) in advance by using a separate step from the viewpoint of improving productivity. . By disposing the conductive filler (D) by such a method, the amount of exhaust gas generated from the disc damper can be further reduced.

[Disc damper and hard disk drive]

Hereinafter, the disc damper and the hard disk drive according to the present embodiment will be described with reference to the drawings, but the present invention is not limited to the following aspects.

Fig. 1 is a schematic view showing a disc damper of the embodiment. The disc damper 1 has a plate portion 11 which is disposed on the disc surface of the disk and is spaced apart from the disc surface. Further, the disc damper 1 is provided with a fixing portion 12 for fixing to a base of the hard disk.

The thickness of the plate portion 11 can be set to 2 mm or less. Further, since the plate portion 11 is composed of the above resin composition, the surface resistivity is 1 × 10 ² to 1 × 10 ⁹ Ω.

The surface roughness of the plate portion 11 is preferably 50 μm or less, preferably 40 μm or less, and 30 μm or less, from the viewpoint of sufficiently reducing the power consumption of the hard disk drive and sufficiently reducing the failure rate of the hard disk drive. good. In the present embodiment, since the plate portion 11 is composed of the above-described resin composition, such a desired surface roughness can be easily achieved.

In order to further reduce the rate of occurrence of the hard disk drive, the amount of exhaust gas generated from the disk damper 1 is preferably 15000 ng/g or less, and preferably 10000 ng/g or less at 85 ° C for 5 hours. It is more preferably 3000 ng/g or less. Further, the amount of exhaust gas generated can be measured by the method described in the examples.

Fig. 2 is a view showing the hard disk drive of the embodiment. The hard disk drive 100 includes a disk damper 1; a disk 2 of a recording portion; a spindle motor 3 for rotating the disk 2; and an actuator 4 for mounting the magnetic head 41 at the tip end portion. The magnetic head 41 provides a portion for reading and writing magnetic recording from the magnetic disk 2 at a certain floating height (for example, 5 to 15 nm).

The plate portion 11 of the disc damper 1 is disposed on the disc surface of the disc 2 so as to be spaced apart from the disc surface. Here, it is preferable that the plate portion 11 is a total area of the magnetic disk 2 to cover 10 to 75%.

The hard disk drive 100 may have a plurality of disk dampers 1 and a disk 2 respectively. In this case, the plurality of disks 2 are arranged to be isolated from each other on the same rotating axis, and are inserted between the disks 2 respectively. The plate portion 11 of the disc damper 1.

In the hard disk drive 100 of the present embodiment, it is possible to sufficiently suppress the vibration of the magnetic disk 2 when the magnetic disk 2 rotates and the wind generated when the magnetic disk 2 rotates, thereby causing the vibration of the actuator 4 to be stably stabilized. Read and write disk information.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

[Examples]

Hereinafter, the present embodiment will be specifically described by way of examples and comparative examples, but the present embodiment is not limited to the examples. The preparation, production method, and evaluation method of the raw materials used in the examples and comparative examples are as follows.

[Modulation of raw materials] [1. Polyamide resin (A)]

Using the polyamine copolymer obtained in the production example described later, and Polyamide resin as described.

A6: PA66 (relative viscosity (η r) = 2.6), A7: PA610 (relative viscosity (η r) = 2.3), A8: will have a trans/body ratio (mol ratio) of 80/20 Polydecylamine obtained by thermal polycondensation of 1,4-cyclohexanedicarboxylic acid and 2-methylpentanediamine (relative viscosity (η r)=2.3), A9:PA9T (relative viscosity (η r)=1.9 ), A10: PA6 (relative viscosity (η r) = 2.4).

[2. Glass fiber (B)]

B1: Glass fiber having an average fiber diameter of 10.5 μm and a fiber cut length of 3 mm.

[3. Inorganic filler (C)]

C1: calcined kaolin (powder average particle diameter = 1.5 μm, γ-aminopropyl triethoxy decane surface treatment, average aspect ratio = 7.8), C2: ash stone (average fiber diameter = 2.2 μm, average fiber length) = 7.2 μm, average aspect ratio = 3.3), C3: glass cullet (average short diameter = 1.1 μm, average particle diameter = 20 μm, average aspect ratio = 20).

[4. Conductive carbon (D)]

D1: Ketjen black (DBP oil absorption 495mL/100g), D2: furnace black (DBP oil absorption 200mL/100g).

[Production Example of Polyamine Resin (A)] [Manufacturing Example 1: Manufacturing of A1]

Adjusting the molar salt of hexamethylenediamine and adipic acid as a polyamide resin An aqueous solution of 12.3 kg which is equivalent to 50% by mass is contained; and a molar salt of hexamethylenediamine and isodecanoic acid is used as a polyamide resin to prepare a 2.7 kg aqueous solution containing 50% by mass. Next, the above aqueous solution was added to an autoclave having a stirring device and having a capacity of 40 liters at the lower portion of the extraction nozzle, and the aqueous solution was sufficiently stirred at 50 °C. Next, after sufficiently replacing the inside of the autoclave with nitrogen, the temperature in the autoclave was raised from 50 ° C to about 270 ° C while stirring the aqueous solution. At this time, the pressure in the autoclave is about 1.8 MPa, and the water is discharged to the outside of the system at any time so that the pressure is not higher than 1.8 MPa. Further, the polymerization time was adjusted such that the relative viscosity (η r) of the polyamide resin became a target value. After completion of the polymerization in the autoclave, the polyamide resin strands were fed linearly from the lower nozzle and cooled and cut with water to obtain a pelletized polyamide 66/6I copolymer. The polyamide resin was vacuum dried at 80 ° C for 24 hours. When η r of the polyamide resin was measured by the following method (method according to JIS K 6810), it was 2.10. Further, the melting point of the polyamide resin was 237 °C.

[Manufacturing Example 2: Manufacturing of A2]

A molar salt of hexamethylenediamine and adipic acid is used as a polyamide resin to prepare a 10.95 kg aqueous solution containing 50% by mass; and a molar salt such as hexamethylenediamine or isophthalic acid is used as the polyamide resin. The preparation contained a relatively 50% by mass of a 4.05 kg aqueous solution. Next, the above aqueous solution was added to an autoclave having a stirring device and having a capacity of 40 liters at the lower portion of the extraction nozzle, and the aqueous solution was sufficiently stirred at 50 °C. Next, after sufficiently replacing the inside of the autoclave with nitrogen, the temperature in the autoclave was raised from 50 ° C to about 270 ° C while stirring the aqueous solution. At this time, the pressure in the autoclave is about 1.8 MPa, and the water is discharged to the outside of the system at any time so that the pressure is not higher than 1.8 MPa. Further, the polymerization time was adjusted such that the relative viscosity (η r) of the polyamide resin became a target value. After the polymerization in the autoclave is finished, the polythene will be collected from the lower nozzle. The amine resin strands were fed linearly and cooled by water and cut to obtain a pelletized polyamine 66/6I copolymer. The polyamide resin was vacuum dried at 80 ° C for 24 hours. When the η r of the polyamide resin was measured by the following method, it was 1.90. Further, the melting point of the polyamide resin was 223 °C.

[Manufacturing Example 3: Manufacturing of A3]

A molar salt of hexamethylenediamine and adipic acid is used as a polyamide resin to prepare a 12.3 kg aqueous solution containing 50% by mass; and a molar salt such as hexamethylenediamine or isophthalic acid is used as the polyamide resin. The preparation contained a 2.7 kg aqueous solution equivalent to 50% by mass. Next, the above aqueous solution was added to an autoclave having a stirring device and having a capacity of 40 liters at the lower portion of the extraction nozzle, and the aqueous solution was sufficiently stirred at 50 °C. Next, after sufficiently replacing the inside of the autoclave with nitrogen, the temperature in the autoclave was raised from 50 ° C to about 270 ° C while stirring the aqueous solution. At this time, the pressure in the autoclave is about 1.8 MPa, and the water is discharged to the outside of the system at any time so that the pressure is not higher than 1.8 MPa. Further, the polymerization time was adjusted such that the relative viscosity (η r) of the polyamide resin became a target value. After completion of the polymerization in the autoclave, the polyamide resin strands were fed linearly from the lower nozzle and cooled and cut with water to obtain a pelletized polyamide 66/6I copolymer. The polyamide resin was vacuum dried at 80 ° C for 24 hours. When the η r of the polyamide resin was measured by the above method (method according to JIS K 6810), it was 1.90. Further, the melting point of the polyamide resin was 237 °C.

[Manufacturing Example 4: Manufacturing of A4]

A molar salt of hexamethylenediamine and adipic acid is used as a polyamide resin to prepare a 12.3 kg aqueous solution containing 50% by mass; and a molar salt such as diamine and isophthalic acid is used as the polyamide resin. The preparation contained a 2.7 kg aqueous solution equivalent to 50% by mass. Next, the above aqueous solution is added to have a stirring device and has a pumping at the lower portion. The aqueous solution was sufficiently stirred at 50 ° C in an autoclave having a nozzle volume of 40 liters. Next, after sufficiently replacing the inside of the autoclave with nitrogen, the temperature in the autoclave was raised from 50 ° C to about 270 ° C while stirring the aqueous solution. At this time, the pressure in the autoclave is about 1.8 MPa, and the water is discharged to the outside of the system at any time so that the pressure is not higher than 1.8 MPa. Further, the polymerization time was adjusted such that the relative viscosity (η r) of the polyamide resin became a target value. After completion of the polymerization in the autoclave, the polyamide resin strands were fed linearly from the lower nozzle and cooled and cut with water to obtain a pelletized polyamide 66/6I copolymer. The polyamide resin was vacuum dried at 80 ° C for 24 hours. When the η r of the polyamide resin was measured by the above method (method according to JIS K 6810), it was 2.40. Further, the melting point of the polyamide resin was 237 °C.

[Manufacturing Example 5: Manufacturing of A5]

A molar salt of hexamethylenediamine and adipic acid is used as a polyamide resin to prepare a 12.3 kg aqueous solution containing 50% by mass; and a molar salt such as hexamethylenediamine or isophthalic acid is used as the polyamide resin. The preparation contained a 2.7 kg aqueous solution equivalent to 50% by mass. Next, the above aqueous solution was added to an autoclave having a stirring device and having a capacity of 40 liters at the lower portion of the extraction nozzle, and the aqueous solution was sufficiently stirred at 50 °C. Next, after sufficiently replacing the inside of the autoclave with nitrogen, the temperature in the autoclave was raised from 50 ° C to about 270 ° C while stirring the aqueous solution. At this time, the pressure in the autoclave is about 1.8 MPa, and the water is discharged to the outside of the system at any time so that the pressure is not higher than 1.8 MPa. Further, the polymerization time was adjusted such that the relative viscosity (η r) of the polyamide resin became a target value. After completion of the polymerization in the autoclave, the polyamide resin strands were fed linearly from the lower nozzle and cooled and cut with water to obtain a pelletized polyamide 66/6I copolymer. The polyamide resin was vacuum dried at 80 ° C for 24 hours. When the η r of the polyamide resin is measured by the above method (method according to JIS K 6810), 2.90. Further, the melting point of the polyamide resin was 237 °C.

[Evaluation method] [Determination of Relative Viscosity of Sulfuric Acid (JIS K 6810)]

A polyamine solvent in which 1 g of polyamine resin was dissolved in 100 mL of 96% sulfuric acid was measured using an Oswald viscometer at 25 ° C and the relative viscosity of sulfuric acid was determined by the following formula.

The relative viscosity of sulfuric acid of the polyamide resin (η r) = (the number of seconds of dropping of the polyamine solution) / (the number of seconds of the sulfuric acid solution)

[Measurement of Bending Elastic Modulus]

The flexural modulus of elasticity for evaluating the properties (mechanical strength) of the machine was measured. An injection molding machine (FN-3000, screw diameter: 40 mm, manufactured by Nissei Resin Co., Ltd.) was used, and the cylinder temperature was 290 ° C, the mold temperature was 90 ° C, the injection pressure was 65 MPa, the injection time was 5 seconds, the cooling time was 25 seconds, and the screw was used. Under the molding conditions of a number of revolutions of 200 rpm, a test piece according to ISO 294 was molded and the test piece for bending test was subjected to cutting. The obtained test piece was measured in accordance with ISO 178 using an autoclave (AG-5000D-shaped, manufactured by Shimadzu Corporation) at a crosshead speed of 5 mm/min, a pitch of 64 mm, and an ambient temperature of 23 °C.

[surface resistivity]

For the obtained disc damper, the surface resistivity of the central portion of the disc damper was measured using a SIMCO surface resistivity meter Worksurface Tester ST-3 manufactured by SIMCO JAPAN.

[Exhaust production]

For the resulting disc damper, use the Dynamic Headspace-Gas Chromatography-Mass Spectrometry (DHS GC-MS) method. The amount of generated exhaust gas was measured.

First, about 1 g of the sample was cut out from the disc damper and placed in a glass box, and N ₂ gas was passed through the inside of the heating oven while being kept at 85 ° C for 3 hours. The gas generated by the sample is collected in a adsorption tube.

Next, while the collected adsorption tube was heated while flowing inert gas, the heat was removed, cooled and concentrated, and then measured by a gas chromatography mass spectrometer (GC-MS). The ionization method of the mass spectrometer was performed by an electron punching method (EI method; 70 eV). From the peak area value detected by the gas chromatograph mass spectrometer, the amount of component (ng) collected by the adsorbent tube is obtained using a calibration curve of hexadecane, and the mass per unit mass is determined by dividing by the sample (g). The amount of exhaust produced.

[surface roughness]

For the obtained disk damper, the surface roughness meter Surfcom made by TOKYO SEIMITSU was used, and the surface roughness Rmax (the maximum height from the average line) was measured at the center portion of the plate portion of the disk damper. ).

[warp deformation degree]

The V-shaped block at both ends of the obtained disc damper is fixed on the platform, and the molded product is placed and the both end portions thereof are fixed in the height direction, and the maximum warpage amount at the center portion is measured and set as the warpage deformation degree. .

[HDD bad rate]

The resulting disc damper was assembled into a hard disk drive and subjected to a 50,000 load/unload test. At this time, the generated defective ratio was measured and evaluated. The case of the poor rate of occurrence of the general assumed level is rated as A, the case where the rate of occurrence of defects is higher than that is evaluated as B, and the case where more is the case is evaluated as C.

[Power Consumption Evaluation]

The resulting disc dampers were assembled into a hard disk drive and subjected to 1000 load/unload tests. At this time, it was connected to a constrain with a power consumption meter, and the amount of electric power consumption was measured and evaluated. The case where the power consumption amount of the general assumed level is rated as A, the case where the amount of power consumption is larger than the case is evaluated as B, and the case where it is more is evaluated as C.

[Example 1]

Using A1 as the polyamide resin (A) and D1 as the conductive carbon (D), the extruder (TEM58SS, manufactured by Toshiba Machine Co., Ltd.) was used in advance in the ratio (adjusted amount) shown in Table 1 Melt mixing and cooling were carried out under the conditions of a cylinder temperature (set temperature) of 260 ° C, a screw revolution of 500 rpm, and a discharge amount of 330 kg / hour. Next, using a TEM48 Φ twin-screw extruder manufactured by Toshiba Machine Co., Ltd., the main feed port provided at the most upstream portion was set at a temperature of 280 ° C, a screw rotation number of 265 rpm, and a discharge amount of 200 kg/h. The cooled composition is supplied. Then, among the side supply ports provided at the downstream side where the polyamide component is sufficiently melted, C1 is used as the inorganic filler (C) from the upstream side and B1 is used as the glass fiber from the downstream side ( B), each of which is supplied in the ratio (mixing amount) shown in Table 1. Then, the strand extruded from the die nozzle (3 mm Φ × 19 holes) provided at the most downstream portion was cooled with water, and cut with a strand cutter to obtain particles of a polyamide resin composition. . The obtained pellets were used and the flexural modulus was measured using the method described above.

Next, using a injection molding machine (SE50D, screw diameter Φ 25 mm, manufactured by Sumitomo Heavy Industries, Ltd.), a disk damper was formed under the molding conditions of a cylinder temperature of 290 ° C, a mold temperature of 100 ° C, and a screw rotation number of 150 rpm. . For the manufactured disk damper, the surface resistivity and the warpage deformation degree were evaluated using the above method. The evaluation results are shown in Table 2. Moreover, the disc damper is covered with a plate as a hard disk. The machine is shaped by 65% of the total area of the disc. Further, the thickness of the plate portion was set to 1.0 mm.

[Example 2-5]

A disc damper was produced and evaluated in the same manner as in the first embodiment except that the amount of the B1 and the C1 was changed as described in Table 1. The evaluation results are shown in Table 2.

[Embodiment 6]

A disc damper was produced and manufactured in the same manner as in the first embodiment except that C2 was used instead of C1 as the inorganic filler (C), and the amounts of B1 and C2 were changed as shown in Table 1. Conduct an evaluation. The evaluation results are shown in Table 2.

[Embodiment 7]

A disc damper was produced and manufactured in the same manner as in the first embodiment except that C3 was used instead of C1 as the inorganic filler (C), and the amounts of B1 and C3 were changed as described in Table 1. Conduct an evaluation. The evaluation results are shown in Table 2.

[Embodiment 8]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A3 was used instead of A1 as the polyamine resin (A). The evaluation results are shown in Table 2.

[Embodiment 9]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A4 was used instead of A1 as the polyamine resin (A). The evaluation results are shown in Table 2.

[Embodiment 10]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A5 was used instead of A1 as the polyamine resin (A). The evaluation results are shown in Table 2.

[Example 11]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A2 was used instead of A1 as the polyamine resin (A). The evaluation results are shown in Table 2.

[Embodiment 12]

A disc damper was produced and evaluated in the same manner as in Example 1 except that D2 was used instead of D1 as the conductive carbon (D). The evaluation results are shown in Table 2.

[Example 13]

A disc damper was produced and evaluated in the same manner as in the first embodiment except that the thickness of the plate portion of the disc damper was set to 1.5 mm. The evaluation results are shown in Table 2.

[Embodiment 14]

A disc damper was manufactured and manufactured in the same manner as in the first embodiment except that the plate portion of the disc damper was formed so as to cover 25% of the total area of the disc of the hard disk drive. Conduct an evaluation. The evaluation results are shown in Table 2.

[Example 15]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A6 was used instead of A1 as the polyamine resin (A). Comment The price results are shown in Table 2.

[Example 16]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A7 was used instead of A1 as the polyamine resin (A). The evaluation results are shown in Table 2.

[Example 17]

A disc damper was produced and manufactured in the same manner as in Example 1 except that A8 was used instead of A1 as the polyamide resin (A) and the set temperature of the twin-screw extruder was changed to 345 °C. Evaluation. The evaluation results are shown in Table 2.

[Embodiment 18]

A disc damper was produced and manufactured in the same manner as in Example 1 except that A9 was used instead of A1 as the polyamide resin (A) and the set temperature of the twin-screw extruder was 320 °C. Evaluation. The evaluation results are shown in Table 2.

[Embodiment 19]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A10 was used instead of A1 as the polyamine resin (A). The evaluation results are shown in Table 2.

[Comparative Example 1]

A disc damper was produced and evaluated in the same manner as in the first embodiment except that the amount of the B1 and the C1 was changed as described in Table 1. The evaluation results are shown in Table 2.

[Comparative Example 2]

A disc damper was produced and evaluated in the same manner as in Example 1 except that D1 was removed from the composition. Evaluation results are as Table 2 shows.

[Comparative Example 3]

A disc damper was produced and evaluated in the same manner as in Example 1 except that B1 was removed from the composition. The evaluation results are shown in Table 2.

[Comparative Example 4]

A disc damper was produced and evaluated in the same manner as in Example 1 except that C1 was removed from the composition. The evaluation results are shown in Table 2.

[Comparative Example 5]

A disc damper was produced and evaluated in the same manner as in Example 1 except that A6 was used instead of A1 as the polyamine resin (A) and C1 was removed from the composition. The evaluation results are shown in Table 2.

[Comparative Example 6]

A dish was produced in the same manner as in Example 1 except that A8 was used instead of A1 as the polyamide resin (A), C1 was removed from the composition, and the set temperature of the twin-screw extruder was changed to 345 °C. The damper was evaluated and evaluated. The evaluation results are shown in Table 2.

[Comparative Example 7]

A disc damper was produced and evaluated in the same manner as in Example 1 except that PC (polycarbonate) was used instead of the polyamide resin (A). The evaluation results are shown in Table 2.

1‧‧‧ disc damper

12‧‧‧ Fixed Department

11‧‧‧ Board Department

Claims (20)

A disc damper for suppressing a disk damper that is disposed on a hard disk drive, which comprises a polyamide resin (A), a glass fiber (B), and an inorganic filler (C) And a resin composition of the conductive filler (D), wherein the mass ratio of the content Y of the inorganic filler (C) to the content X of the glass fiber (B) in the resin composition is Y/ X is 2.5 or less. The disc damper according to claim 1, wherein the inorganic filler (C) has an average aspect ratio of 1.0 to 100. The disc damper according to claim 1 or 2, wherein the conductive filler (D) is conductive carbon. The disc damper according to any one of claims 1 to 3, wherein the disc damper has a plate portion attached to a disc surface of the magnetic disk, and the disc The sheet surface is disposed to be isolated, and the thickness of the plate portion is 2 mm or less. The disc damper according to any one of claims 1 to 4, wherein the disc damper has a plate portion attached to a disc surface of the magnetic disk, and the disc The sheet surface is disposed to be isolated, and the surface resistivity of the aforementioned plate portion is 1 × 10 ² to 1 × 10 ⁹ Ω. The disc damper according to any one of claims 1 to 5, wherein the disc damper has a plate portion attached to a disc surface of the magnetic disk, and the disc The sheet surface is disposed to be isolated, and the surface roughness of the plate portion is 50 μm or less. The disc damper according to any one of claims 1 to 6, wherein the amount of exhaust gas generated at 85 ° C for 5 hours is 15000 ng / g. the following. The disc damper according to any one of claims 1 to 7, wherein the inorganic filler (C) is selected from the group consisting of wollastonite, mica, kaolin, talc, glass cullet, glass. Inorganic fillers in groups of beads and glass balloons. The disc damper according to any one of claims 1 to 8, wherein the total amount of the glass fiber (B) and the inorganic filler (C) in the resin composition is the same as the resin The total amount of the composition is calculated to be 40% by mass or more. The disc damper according to any one of the preceding claims, wherein the total amount of the glass fiber (B) and the inorganic filler (C) in the resin composition is the same as the resin The total amount of the composition is calculated to be 45% by mass or more. The disc damper according to any one of claims 1 to 10, wherein the aforementioned mass ratio Y/X is 0.2 to 1.5. The disc damper according to any one of claims 1 to 11, wherein the polyamide resin (A) contains an aliphatic polyamine resin, an alicyclic polyamide resin, and At least one of the groups of semi-aromatic polyamide resins. The disc damper according to any one of claims 1 to 12, wherein the polyamido resin (A) has a hexamethylene adipamide unit and a hexamethylene Indoleamine unit. The disc damper according to any one of the preceding claims, wherein the resin composition is 50 to 150 parts by mass based on 100 parts by mass of the polyamide resin (A). Glass fiber (B), 10 to 40 parts by mass The inorganic filler (C) and 5 to 20 parts by mass of the above-mentioned conductive filler (D). The disc damper according to any one of claims 1 to 14, wherein the polyamine resin (A) is based on JIS K 6810 and is used in a concentration of 1% and 25 ° C in 96% sulfuric acid. The polyamidamide resin having a relative viscosity (η r) of 1.5 to 4.5 was measured. The disc damper according to any one of claims 1 to 15, wherein the inorganic filler (C) is calcined kaolin or ash. The disc damper according to any one of claims 1 to 16, wherein the conductive filler (D) is a conductive carbon having a dibutyl phthalate oil absorption of 250 mL/g or more. The disc damper according to any one of claims 1 to 17, wherein the conductive filler (D) does not contain carbon fibers. A disk damper having a disk and a disk damper according to any one of claims 1 to 18, wherein the disk damper has a plate portion attached to the disk The disc surface is arranged to be isolated from the disc surface. The hard disk drive according to claim 19, wherein 10 to 75% of the total area of the disk surface is covered by the plate portion.