JP2007039577A - Antistatic polyamide resin molded article having improved heat resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic polyamide resin molded article compounded with a carbon-based filler, having no problem in molding defect, and also having improved heat resistance. <P>SOLUTION: The polyamide resin molded article comprises 0.02-3 pts.wt. of at least one kind selected from diphenylamine and the derivative thereof based on 100 pts.wt. of a polyamide resin, and the carbon-based filler, and has a volume resistivity of 10<SP>2</SP>-10<SP>12</SP>(Ω cm) level, measured based on JIS K6911. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an antistatic polyamide resin molded article having improved heat resistance, and in particular, a polyamide resin molded article having improved heat resistance without impairing antistatic properties by containing a specific heat stabilizer. About.

  In the electronic device manufacturing process, if the device is charged with static electricity for any reason during the process, the antistatic property such as a pallet made of a resin molded body with antistatic performance or conductivity is provided to quickly discharge the static electricity. Sex parts are used. As the antistatic resin molding, polyamide resin moldings containing various carbon fine particles are used (for example, Patent Documents 1 to 3).

Among antistatic components, shuttle pockets, sockets, device guides and the like are required to have a heat resistance of about 140 to 150 ° C. in addition to the above antistatic properties. At present, so-called super engineering plastics such as polyetheretherketone and polyimide imparted with antistatic properties are exclusively used to satisfy both of these characteristics, but these resins are very expensive. is there. Thus, attempts have been made to use aluminum. However, aluminum has a problem of poor wear resistance, large wear due to repeated use, and wear powder adhering to semiconductor components.

The polyamide resin molded body is much cheaper than the super engineering plastic, but is likely to undergo oxidative degradation. Thus, it is known to obtain a polyamide resin molded article having improved weather resistance by polymerizing in the presence of an amine-based antioxidant (Patent Document 4). The molded body can contain carbon black for improving the releasability. However, if the amount of carbon black is more than 3 parts by weight with respect to 100 parts by weight of ω-lactam, it is considered that molding failure occurs. .
Japanese Patent No. 2624483 Japanese Patent No. 3419964 JP 2004-307549 A JP 2003-12922 A

However, in order to provide the required antistatic properties, a carbon-based filler such as carbon black in an amount greater than 3 parts by weight must be blended. Accordingly, an object of the present invention is to provide a polyamide resin molded body having improved heat resistance without problems such as molding defects in the polyamide resin molded body in which such a large amount of carbon-based filler is blended.

As a result of trying various heat stabilizers, the present inventors have found that the above object can be achieved by using a specific heat stabilizer. That is, the present invention includes 0.02 to 3 parts by weight of at least one selected from diphenylamine and its derivatives and a carbon-based filler with respect to 100 parts by weight of polyamide resin, and is measured in accordance with JIS K6911. The polyamide resin molded product is characterized by having a volume resistivity of the order of 10 ² to 10 ¹² (Ω · cm).

The polyamide resin molded product of the present invention can be molded without any problem, and does not impair the antistatic performance. Further, even after being held at 150 ° C. for 500 hours, no crack is generated, and almost the initial antistatic performance and mechanical strength are exhibited.

The polyamide resin molded article of the present invention is characterized by containing a predetermined amount of a diphenylamine-based heat stabilizer. The heat stabilizer includes not only diphenylamine but also diphenylamine derivatives. The derivatives of diphenylamine include diphenylamine having a substituent on the phenyl group, such as dioctyldiphenylamine, styrenated diphenylamine, octylated styrenated diphenylamine, 4,4′-bis (4-α, α′-dimethylbenzyl) diphenylamine, Examples include butyl / octylated diphenylamine. Even if the compound name does not have “diphenylamine”, the compound may contain a diphenylamine structure, and one amino group of p-phenylenediamine is substituted with a phenyl group, for example, N-isopropyl -N'-phenyl-p-phenylenediamine can also be used. Preferably, octylated diphenylamine, styrenated diphenylamine, octylated styrenated diphenylamine and 4,4'-bis (4-α, α'-dimethylbenzyl) diphenylamine are used.

The blending amount of the heat stabilizer is 0.02 to 3 parts by weight, preferably 0.2 to 1 part by weight, more preferably 0.2 to 0.8 parts by weight with respect to 100 parts by weight of the polyamide resin. . If the amount of the stabilizer is less than the lower limit, it is difficult to achieve the target heat resistance. On the other hand, if the amount exceeds the upper limit, the volume resistivity increases by 10 compared to the case where no stabilizer is added. It exceeds ² Ωcm, making it difficult to achieve the required antistatic properties. In the present specification, the resin component means a portion that burns up to 500 ° C. when the molded body is subjected to thermal analysis, and may include components such as a promoter in addition to ω-lactam. In the actual molding step, the heat stabilizer may be blended in the above blending amount with respect to 100 parts by weight of ω-lactam. This is because the amount of the cocatalyst or the like is usually a small amount, and the weight of the total amount of the polyamide resin is approximately the same as the weight of ω-lactam.

The molded article of the present invention has a volume resistivity on the order of 10 ² to 10 ¹² (Ω · cm). The molded body exceeding the resistivity cannot release static electricity well. In addition, a molded product having a resistivity lower than the order of 10 ² (Ω · cm) may spark due to excessive antistatic property and cause electrostatic breakdown of the device. Here, the order represents a range of resistivity. For example, “10 ¹² order” means a range of 1 × 10 ¹² or more and less than 1 × 10 ¹³ . Further, the order of 10 (in the above example, “12”) may be expressed as the “order” of the resistance value.

  In the present invention, the volume resistivity is measured at a voltage of 10 V in accordance with JIS K6911. However, in the present invention, since the measurement is performed by directly sandwiching the electrode of the cell box without using the conductive rubber or conductive paint specified in JIS K6911, the contact resistance is higher than that of the rubber or paint. It is considered that a lower value can be obtained when measured as defined in K6911.

The resistivity is achieved by adding a carbon-based filler, and can be adjusted to a desired value within the resistivity range by appropriately selecting the type, particle size, and addition amount. Examples of the carbon-based filler include graphite, such as artificial graphite and natural graphite; calcined resin, such as calcined phenol resin, and calcined acrylic resin; and carbon black, preferably artificial graphite, natural graphite, calcined phenol resin. Is used. For example, when artificial graphite filler is used and volume resistivity on the order of 10 ² to 10 ⁶ (Ω · cm) is desired, the graphitization degree is high due to the high firing temperature, and the true specific gravity is 2.20 or more. The artificial graphite having an average particle diameter of 1 to 30 μm, preferably 3 to 20 μm, more preferably 5 to 10 μm is selected, and 10 to 40 parts by weight, preferably 15 to 20 parts by weight with respect to 100 parts by weight of the polyamide resin. Added. If volume resistivity on the order of 10 ⁶ to 10 ¹² (Ω · cm) is desired, the degree of graphitization is low due to the low firing temperature, the true specific gravity is less than 2.20, and the average particle size is 5 to 30 μm, preferably Artificial graphite of 10 to 20 μm is selected and added to 5 to 15 parts by weight, preferably 7 to 10 parts by weight, based on 100 parts by weight of the polyamide resin.

The ω-lactam used for the preparation of the shaped article of the present invention preferably has 4 to 12 carbon atoms, and includes, for example, γ-butyrolactam, ε-caprolactam, ω-enantolactam, ω-caprolactam, ω -Laurolactam and mixtures thereof. Of these, ε-caprolactam, ω-laurolactam and a mixture thereof are preferable.

The above-mentioned carbon fine particles, an anionic polymerization catalyst and an optional co-catalyst are blended and mixed with the ω-lactam, and injected into a mold for anionic polymerization. The polymerization method is not particularly limited, but is preferably performed by a monomer cast method.
A well-known thing can be used as an anionic polymerization catalyst. Examples include alkali metals such as lithium, sodium, potassium; alkaline earth metals such as magnesium, calcium; and hydrides of these metals such as lithium hydride, sodium hydride, potassium hydride; oxides such as sodium oxide Hydroxides such as sodium hydroxide, potassium hydroxide; carbonates such as sodium carbonate, potassium carbonate; alkylates such as methyl sodium, ethyl sodium, methyl potassium, ethyl potassium; alkoxides such as sodium methylate, Sodium ethylate, potassium methylate, potassium ethylate; Grignard compounds such as methylmagnesium bromide, ethylmagnesium bromide; reaction products with ω-lactams such as sodium ω-lactam Um salts, and potassium salts; and mixtures thereof. Preferably sodium hydride is used.

  The addition amount of the alkali catalyst is usually 0.05 to 10 mol%, more preferably 0.1 to 2 mol%, where the total of ω-lactam and the catalyst is 100 mol%.

  As the polymerization cocatalyst, any polymerization cocatalyst known in the anionic polymerization of nylon monomers can be used, and various isocyanate compounds, urea derivatives, acyllactams, and mixtures thereof can be used. Examples include tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, m-xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, polyisocyanates such as polymethylene polyphenylene polyisocyanate and carbodiimide modified diisocyanates Carbamide lactams such as 1,6-hexamethylenebiscarbamide caprolactam and N, N′-diphenyl-p-phenylenebiscarbamide caprolactam, N-acetyl-ε-caprolactam, triallyl isocyanurate, acid chloride such as terephthaloyl Chloride, adipoyl chloride and sebacoyl chloride, polyacyl lactams such as adipoyl biscaprolactam and terephthaloid Bis caprolactam, 1,3-diphenyl urea, and mixtures thereof. Preferably, diisocyanates and carbamide lactams are used.

  The addition amount of the polyfunctional cocatalyst is 0.02 to 4.0 mol%, preferably 0.1 to 2.0 mol%, where the total of ω-lactam and the polymerization cocatalyst is 100 mol%.

The polymerization temperature is not lower than the melting point of the monomer used and not higher than the melting point of the molded nylon, and is usually in the range of 120 to 200 ° C. The polymerization time is usually within 30 minutes. In addition, you may mix | blend additives, such as a pigment, dye, a reinforcing agent, an antibacterial agent, with the molded object of this invention in the range which does not impair the objective of this invention.

The molded body of the present invention is further subjected to secondary processing such as cutting to become parts for various antistatic uses. Examples of such parts include device guides used in device mounting processes and test processes in semiconductor related product manufacturing processes, handling jigs such as shuttle pockets, sockets, trays, liners, plates, etc. It is also suitable for applications such as transport pallets, housings, roller wheels, gears, bearings, guides, etc. used in the required environment.
EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

The following substances were used in the examples and comparative examples.
Thermal stabilizer No.
1． Dioctyldiphenylamine (manufactured by King Industry, NA-LUBE AO-110 (trade name))
2. Styrenated diphenylamine (manufactured by Kawaguchi Chemical Industry Co., Ltd., Antage DDA (trade name))
3. Octylated styrenated diphenylamine (manufactured by Kawaguchi Chemical Industry Co., Ltd., ANTAGE OD (trade name))
4.4,4′-bis (4-α, α′-dimethylbenzyl) diphenylamine (manufactured by Bayer, Nugard445 (trade name))
5. N-isopropyl-N′-phenyl-p-phenylenediamine (manufactured by Kawaguchi Chemical Industry Co., Ltd., ANTAGE 3C (trade name))
6.1,3-Benzenedicarboxamide-N, N′-bis (2,2,6,6, -tetramethyl-4-piperidyl (manufactured by Clariant, Nyrostub (trade name))
7). Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (manufactured by Ciba Specialty Chemicals, IRGANOX 1010 (trade name))
8). N, N′-hexane-1,6-diylbis [3,5-di-tert-butyl-4-hydroxyphenylpropionamide] (manufactured by Ciba Specialty Chemicals, IRGANOX 1098 (trade name))
9. Tris (2,4-di-tert-butylphenyl) phosphite (Ciba Specialty Chemicals, IRGAFOS 168 (trade name))
10. Diocudadecyl-3,3′-thiodipropionate (Clariant, Hostanox SE4 (trade name))
Filler a. Manufactured by Showa Denko KK, artificial graphite, UFGC30 (trade name)
b. Manufactured by Showa Denko KK, artificial graphite, UFG10 (trade name)
c. Air Water Velpearl Co., baked phenolic resin, Bell Pearl CC-2000S (trade name)

Preparation of molded body Take 2000 g of anhydrous ε-caprolactam in a stainless steel beaker and heat it to a temperature of 140-160 ° C. 300 parts of the filler shown in Table 1 which was heated to a temperature of 140 to 160 [deg.] C. in advance and parts by weight shown in Table 1 with respect to the total amount of [epsilon] -caprolactam were added and mixed. On the other hand, 1000 g of anhydrous ε-caprolactam was taken in another beaker, and 6 g of sodium hydride (oiliness 63%) as a polymerization catalyst was added thereto, and the temperature was adjusted to 140 to 160 ° C. The contents of both beakers were mixed, poured into a 30 mm × 250 mm × 400 mm molding die preheated to 150 ° C., polymerized for 20 minutes, and then taken out. From the obtained molded body, 5 mm × 100 mm × 100 mm test pieces for volume resistivity measurement and tensile test were sampled and evaluated. The results are shown in Table 1.

(1) Measuring method of volume resistivity The test piece was measured by a double electrode method based on JIS K6911 using an electrometer R8340 / A (manufactured by Advantest Co., Ltd.).

(2) Measuring method of tensile strength The tensile strength was measured according to ASTM D-638 using an Intesco 225 type precision universal material testing machine.

(3) Evaluation of heat resistance After holding the test piece in a hot air oven set at 150 ° C for 500 hours, the appearance, volume resistivity, and tensile strength retention were evaluated. As for the appearance, the presence or absence of cracks was visually observed, and “A” was given without cracks and “X” was given. Moreover, the volume resistivity and the tensile strength were not measured for those in which cracks were observed (indicated by “−” in the table).

Comparative Example 1 does not contain a thermal stabilizer and has a volume resistivity of 8 × 10 ^{8 (} Ω · cm). The volume resistivity of the molded body of the example was +10 ² (Ω · cm) or less from the volume resistance of Comparative Example 1, that is, 8 × 10 ¹⁰ (Ω · cm) or less.
In Comparative Example 2, an amine heat stabilizer other than diphenylamine or a derivative is blended. The resistivity was 8 × 10 ¹⁰ (Ω · cm) or less, and cracks were not generated, but the resistivity after thermal aging was not constant, and the tensile strength retention rate was poor.
Comparative Examples 3 and 4 contain a thermal stabilizer in an amount outside the scope of the present invention. Comparative Example 3 had poor heat resistance, and Comparative Example 4 had a volume resistivity greater than +10 ² (Ω · cm) from the volume resistivity of Comparative Example 1.
In Comparative Examples 7 and 8 containing a phenol-based heat stabilizer, molding failure occurred and the initial volume resistivity could not be measured.
In Comparative Example 7, a phosphorus-based heat stabilizer was used, but the volume resistivity was remarkably increased.
Comparative Example 8 uses a sulfur-based heat stabilizer. Although the initial resistivity was small, the thermal stability was poor and cracks occurred.

  The molded body of the present invention has improved heat resistance without impairing antistatic properties by containing a predetermined amount of a predetermined heat stabilizer. The molded body is suitable for applications such as device guides, shuttle pockets, sockets, trays, liners, and plates used in device mounting processes and test processes in semiconductor manufacturing processes.

Claims (5)

The volume resistivity measured according to JIS K6911 includes 10 to 0.03 to 3 parts by weight of at least one selected from diphenylamine and derivatives thereof and a carbon-based filler with respect to 100 parts by weight of the polyamide resin. A polyamide resin molded product characterized by being on the order of ² to 10 ¹² (Ω · cm). The diphenylamine-based heat stabilizer includes octylated diphenylamine, styrenated diphenylamine, octylated styrenated diphenylamine, 4,4′-bis (4-α, α′-dimethylbenzyl) diphenylamine, and N-isopropyl-N′-phenyl. The polyamide resin molded article according to claim 1, wherein the polyamide resin molded article is at least one selected from the group consisting of -p-phenylenediamine. The polyamide resin molded body according to claim 1 or 2, wherein the carbon-based filler is at least one selected from the group consisting of artificial graphite, natural graphite, and fired resin. The volume resistivity is on the order of 10 ² to 10 ⁶ (Ω · cm), and 10 to 40 parts by weight of a carbon-based filler is included with respect to 100 parts by weight of the polyamide resin. The polyamide resin molded product according to any one of the preceding claims. The volume resistivity is on the order of 10 ⁶ to 10 ¹² (Ω · cm), and 5 to 15 parts by weight of a carbon-based filler is included with respect to 100 parts by weight of the polyamide resin. The polyamide resin molded product according to claim 1.