JP4465039B2 - Grinding fluid for aluminum or its alloys - Google Patents

Description

  The present invention relates to a grinding fluid for aluminum or an alloy thereof, and particularly to a grinding fluid for aluminum or an alloy thereof suitable for grinding a hard disk substrate.

  In recent years, with the increase in capacity of hard disks, there is a significant demand for higher recording density. Along with this, the requirements for the surface quality of hard disk substrates are also becoming more sophisticated. In addition, along with the price reduction of hard disks, there is also a demand to increase product yield in order to reduce substrate manufacturing costs.

  An aluminum alloy is often used for a substrate of a hard disk as a recording medium. In general, an aluminum alloy plate for a hard disk is manufactured by the following method. First, the rolled aluminum coil is punched into a donut-shaped disk, and the disks are stacked. Next, pressure annealing is performed to ensure the flatness of the disk, and the inner and outer circumferences of the disk are end-cut. Thereafter, double-side grinding is performed to produce an aluminum alloy substrate.

  In general, a PVA grindstone is used for grinding the aluminum alloy plate for a hard disk, and a method of grinding both surfaces simultaneously using a double-sided lapping machine is used. However, such a grinding method has the following problems as the grinding amount increases. Clogging occurred on the entire contact surface of the grinding stone substrate, and the grinding efficiency was reduced. Further, scratches were generated on the ground surface of the substrate due to grinding sludge and falling abrasive grains generated during grinding. Furthermore, clogging locally occurred on the substrate contact surface of the grindstone, and scratches (scratches) occurred on the substrate.

Therefore, for example, machining fluids described in Patent Documents 1 to 8 have been proposed as grinding fluids for aluminum alloys.
JP 2000-144110 A JP 2001-294888 A JP 2002-241742 A JP 2003-41285 A JP-A-5-258294 Japanese Patent Publication No.8-7864 JP-A-8-20765 JP-A-11-209746

  However, regardless of which of the above-mentioned processing fluids is used, during substrate grinding, there are occurrences of overall and local clogging on the substrate contact surface of the grindstone, and scratches caused by grinding sludge and falling abrasive grains on the substrate grinding surface. The occurrence could not be sufficiently suppressed. In particular, local clogging on the substrate contact surface of the grindstone is considered to occur due to the following mechanism. Grinding sludge generated during grinding of aluminum or an alloy thereof enters the grindstone pores, and aluminum oxide aggregates and accumulates on the inner walls of the grindstone pores. Therefore, when the said aluminum oxide appears on the surface by abrasion of the grindstone at the time of grinding, it is recognized as local clogging. As a result, it is considered that scratches are generated on the substrate surface in contact with the locally clogged portion.

  The present invention sufficiently suppresses the occurrence of general and local clogging on the substrate contact surface of the grindstone during grinding of aluminum or its alloy substrate, resulting from grinding sludge and falling abrasive grains on the substrate grinding surface. An object of the present invention is to provide a grinding fluid for aluminum or its alloy that sufficiently suppresses the occurrence of scratches.

The present invention
(A) 2 to 15% by weight of a monocarboxylic acid having 12 to 18 carbon atoms;
(B) 3-15% by weight of an alicyclic dicarboxylic acid;
(C) The water-soluble amine contains at least an equivalent amount required for neutralization of the monocarboxylic acid (A) and the alicyclic dicarboxylic acid (B); and (D) contains 15% by weight or more of a nonionic surfactant. The present invention relates to a grinding fluid for aluminum or alloys thereof.

  According to the grinding fluid for aluminum or its alloy according to the present invention, it is possible to sufficiently suppress the occurrence of general and local clogging on the substrate contact surface of the grindstone when grinding a substrate made of aluminum or its alloy. And generation | occurrence | production of the scratch resulting from the grinding sludge and falling abrasive grain in a substrate grinding surface can also be fully suppressed. As a result, a substrate with excellent surface roughness and suppressed generation of scratches can be obtained with high productivity.

  The grinding fluid according to the present invention (hereinafter, sometimes simply referred to as a machining fluid) is used after being diluted with water when grinding aluminum or an alloy thereof (hereinafter referred to as an aluminum alloy or the like). The grinding fluid of the present invention may contain water or not contain water as long as it is diluted with water at the time of use.

  The processing oil of the present invention contains at least the following components (A) to (D), and usually further contains water as the balance.

Component (A);
Component (A) is a monocarboxylic acid having 12 to 18 carbon atoms, specifically an aliphatic hydrocarbon compound having the same carbon number and having only one carboxyl group in the molecule. Examples of such monocarboxylic acids include unsaturated aliphatic monocarboxylic acids and saturated aliphatic monocarboxylic acids. From the viewpoint of more effectively suppressing local clogging of the grindstone, it is preferable to use at least an unsaturated aliphatic monocarboxylic acid.

  Specific examples of the unsaturated aliphatic monocarboxylic acid include myristoleic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and elaidic acid. The preferred carbon number of the unsaturated aliphatic monocarboxylic acid is 14-18, especially 16-18. The most preferred unsaturated aliphatic monocarboxylic acid is oleic acid.

  Specific examples of the saturated aliphatic monocarboxylic acid include myristic acid, palmitic acid, stearic acid, and the like. The preferred carbon number of the saturated aliphatic monocarboxylic acid is 14-18, especially 16-18.

  Such unsaturated aliphatic monocarboxylic acids and saturated aliphatic monocarboxylic acids are readily available as commercial products.

Content of a component (A) is 2 to 15 weight%, Preferably it is 2 to 10 weight%. When there are too many components (A), the grindstone will be clogged as a whole, and scratches will occur on the substrate. When the component (A) is too small, local clogging occurs in the grindstone, and scratches occur in the substrate. As the component (A), two or more kinds of compounds may be used, and in this case, the total content thereof may be within the above range.
In the present specification, the content is expressed as a ratio to the total amount of the machining fluid.

Component (B);
Component (B) is an alicyclic dicarboxylic acid, specifically an alicyclic hydrocarbon compound having only two carboxyl groups in the molecule. Examples of such alicyclic dicarboxylic acid include cycloolefin dicarboxylic acid having an unsaturated bond in the carbocyclic ring and cycloparaffin dicarboxylic acid having a saturated carbocyclic ring structure. From the viewpoint of more effectively suppressing the overall clogging of the grindstone, it is preferable to use only cycloolefin dicarboxylic acid as the component (B). If an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid is used in place of the alicyclic dicarboxylic acid, the grindstone is totally clogged, and the substrate is scratched.

で表されるシクロオレフィンジカルボン酸（以下、シクロオレフィンジカルボン酸（ｂ１）という）が挙げられる。Examples of the cycloolefin dicarboxylic acid include general formula (b1);

And a cycloolefin dicarboxylic acid (hereinafter referred to as cycloolefin dicarboxylic acid (b1)).

In general formula (b1), R ¹ is an alkylene group having 4 to 10 carbon atoms, preferably 6 to 8 carbon atoms.
R ² is a single bond (-) or an alkylene group having 1 to 3 carbon atoms, preferably a single bond.
R ³ is an alkyl group having 4 to 8 carbon atoms, preferably 5 to 7 carbon atoms. The alkyl group may be linear or branched, and is preferably linear.

  Specific examples of the cycloolefin dicarboxylic acid (b1) include, for example, 8- (5-carboxy-4-hexyl-2-cyclohexen-1-yl) octanoic acid and 8- (6-carboxy-4-pentyl-2-cyclohexene). -1-yl) octanoic acid, 8- (6-carboxy-4-hexyl-2-cyclohexen-1-yl) octanoic acid, and the like. The most preferred cycloolefin dicarboxylic acid is 8- (5-carboxy-4-hexyl-2-cyclohexen-1-yl) octanoic acid.

  The cycloolefin dicarboxylic acid (b1) is available as, for example, commercially available Diacid 1550 (manufactured by Harima Chemicals Co., Ltd.).

で表されるシクロパラフィンジカルボン酸（以下、シクロパラフィンジカルボン酸（ｂ２）という）が挙げられる。Examples of cycloparaffin dicarboxylic acid include general formula (b2);

And cycloparaffin dicarboxylic acid (hereinafter referred to as cycloparaffin dicarboxylic acid (b2)).

In the general formula (b2), R ⁴ is an alkylene group having 4 to 10 carbon atoms, preferably 6 to 8 carbon atoms.
R ⁵ is a single bond (-) or an alkylene group having 1 to 3 carbon atoms, and preferably a single bond.
R ⁶ is an alkyl group having 4 to 8 carbon atoms, preferably 5 to 7 carbon atoms. The alkyl group may be linear or branched, and is preferably linear.

  Specific examples of the cycloparaffin dicarboxylic acid (b2) include, for example, 8- (6-carboxy-4-hexyl-cyclohexyl) octanoic acid, 8- (3-carboxy-4-hexyl-cyclohexyl) octanoic acid, and the like.

  Content of a component (B) is 3 to 15 weight%, Preferably it is 3 to 10 weight%. If the component (B) is too much, the grindstone will be clogged as a whole, and scratches will occur on the substrate. If the component (B) is too small, the grindstone will be clogged as a whole and grinding efficiency will be reduced. Two or more types of compounds may be used as the component (B), and in this case, the total content thereof may be within the above range.

Component (C);
Component (C) is a water-soluble amine, for example, alkylamines such as ethylamine and propylamine; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and triisopropanolamine; morpholine and the like A cyclic amine; an alkyl alkanolamine such as ethyldiethanolamine; an alkyl diamine such as metaxylenediamine; and the like. A preferred water-soluble amine is alkanolamine.

  Content of a component (C) is more than the equivalent required for neutralizing a component (A) and (B), Preferably it is 10-25 weight%. When there is too little component (C), the solubility to water will fall. Two or more kinds of compounds may be used as the component (C), and in this case, the total content thereof may be within the above range.

Component (D);
Component (D) is a nonionic surfactant, and any nonionic surfactant conventionally used in the field of grinding fluids can be used. Examples of such nonionic surfactants include polyoxyalkylene, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenyl ether, and polyoxyalkylene alkyl ester. From the viewpoint of suppressing clogging of the entire grindstone, it is preferable to use at least one compound selected from polyoxyalkylene, polyoxyalkylene alkyl ether, and polyoxyalkylene alkylphenyl ether. More preferably, at least polyoxyalkylene and polyoxyalkylene alkyl ether are used in combination. More preferably, at least polyoxyalkylene, polyoxyalkylene alkyl ether, and polyoxyalkylene alkylphenyl ether are used in combination. When an anionic surfactant or a cationic surfactant is used instead of the component (D), the zeta potential is affected and local clogging occurs.

As polyoxyalkylene, for example, general formula (d1);
_{HO (CH 2 CH 2 O)} p1 - (CH 2 CH (CH 3) O) p2 - (CH 2 CH (C 2 H 5) O) p3 -H (d1)
And polyoxyalkylene (hereinafter referred to as polyoxyalkylene (d1)).

In the general formula (d1), p1 + p2 + p3 is not particularly limited as long as the molecular weight falls within the range described later, and p1, p2 and p3 are each independently an integer of 0 or more (provided that p1, p2 And p3 are not simultaneously 0). Usually, p1 is an integer of 1 or more, particularly 3 to 6, and p2 and p3 are each independently an integer of 0 or more, particularly 0 to 8. Preferably, the ratio between p1 and p2 + p3 is 10:90 to 90:10.
The polyoxyalkylene (d1) may have a oxyalkylene part such as an oxyethylene part, an oxypropylene part, or an oxybutylene part in a block type or a random type, but is preferably a block type.

  Polyoxyalkylene (d1) can be obtained as commercially available Pluronic (manufactured by BASF Japan).

Examples of the polyoxyalkylene alkyl ether include the general formula (d2);
^{_{R 7 O (CH 2 CH 2}} O) n1 - (CH 2 CH (CH 3) O) n2 - (CH 2 CH (C 2 H 5) O) n3 -H (d2)
And polyoxyalkylene alkyl ethers (hereinafter referred to as polyoxyalkylene alkyl ethers (d2)).

In general formula (d2), R ⁷ is an alkyl group having 8 to 18 carbon atoms, preferably 10 to 14 carbon atoms.
n1 + n2 + n3 is not particularly limited as long as the molecular weight falls within the range described later, and n1, n2, and n3 are each independently an integer of 0 or more (provided that n1, n2, and n3 are not 0 at the same time) ). Usually, n1 is an integer of 1 or more, particularly 3 to 9, and n2 and n3 are each independently an integer of 0 or more, particularly 0 to 2. Preferably, the ratio between n1 and n2 + n3 is 10:90 to 100: 0.
When n2 and n3 are each independently 1 or more, the polyoxyalkylene alkyl ether (d2) may be a random type, even if the oxyalkylene part such as an oxyethylene part, an oxypropylene part, or an oxybutylene part is a block type In particular, a block type is preferable.

  Polyoxyalkylene alkyl ether (d2) is available as commercially available Lutensol (manufactured by BASF Japan).

Examples of the polyoxyalkylene alkylphenyl ether include the general formula (d3);
_{^{R 8 -Ph-O (CH 2}} CH 2 O) m1 - (CH 2 CH (CH 3) O) m2 - (CH 2 CH (C 2 H 5) O) m3 -H (d3)
And polyoxyalkylene alkylphenyl ether (hereinafter referred to as polyoxyalkylene alkylphenyl ether (d3)).

In the general formula (d3), R ⁸ is an alkyl group having 6 to 10 carbon atoms, preferably 8 to 9 carbon atoms.
Ph is a phenylene group, preferably a 1,4-phenylene group.
m1 + m2 + m3 is not particularly limited as long as the molecular weight falls within the range described below, and m1, m2, and m3 are each independently an integer of 0 or more (provided that m1, m2, and m3 are not 0 at the same time) ). Normally, m1 is an integer of 1 or more, particularly 1 to 12, and m2 and m3 are each independently an integer of 0 or more, particularly 0 to 10. Preferably, the ratio of m1 to m2 + m3 is 10:90 to 100: 0.
When m2 and m3 are each independently 1 or more, the polyoxyalkylene alkylphenyl ether (d3) may be a block type oxyalkylene part such as an oxyethylene part, an oxypropylene part, or an oxybutylene part, or randomly Although it may be a mold, a block type is particularly preferable.

  Polyoxyalkylene alkylphenyl ether (d3) is available as commercially available nonipol (manufactured by Sanyo Chemical Industries, Ltd.).

  The average molecular weight of the nonionic surfactant is usually 200 to 10,000 in terms of weight average molecular weight.

  The content of the component (D) is 15% by weight or more, particularly 15 to 90% by weight, preferably 15 to 80% by weight, more preferably 30 to 50% by weight. If the component (D) is too small, the grindstone will be clogged as a whole and grinding efficiency will be reduced. Two or more kinds of compounds may be used as the component (D), and in this case, the total content thereof may be within the above range.

  As long as the working fluid of the present invention is diluted with water at the time of use, it does not necessarily contain water, but usually a predetermined amount of the above components are added to the remaining water and sufficient It is manufactured by mixing. The processing fluid of the present invention exhibits sufficient storage stability even when it contains water.

  The working fluid of the present invention is contained in a container and traded on the market. At the time of grinding, the working fluid is diluted 20 to 1000 times, preferably 100 to 1000 times by weight, with water as an aqueous solution for grinding. used. Grinding is performed by interposing such a water dilution body (aqueous solution for grinding) of the working fluid between the aluminum alloy to be ground and the grindstone.

  As the grindstone, those conventionally used for grinding aluminum alloys or the like can be used, and examples thereof include a porous grindstone represented by a PVA grindstone.

  The working fluid of the present invention provides the effect of the present invention, particularly the effect of simultaneously suppressing both the overall and local clogging of the grindstone. The details of the mechanism are not clear, but are thought to be based on the following phenomenon. By using the components (A) to (D) in combination, the absolute value of the zeta potential of the aluminum-based fine powder generated during grinding can be increased. Therefore, the dispersibility of the aluminum-based fine powder is improved, and aggregation / accumulation on the inner wall of the grindstone is suppressed. As a result, it is considered that both the overall and local clogging of the grindstone are simultaneously suppressed and the effect of the present invention can be obtained.

  The working fluid of the present invention exhibits a zeta potential of −50 mV or less, particularly −60 to −50 mV, with respect to the aluminum fine powder generated when the aluminum alloy is ground by dilution with water at the aforementioned magnification.

(Example / Comparative Example)
The processing liquid was prepared by mixing the components described in the table. The machining fluid was evaluated for the following items.

(Zeta potential)
A working solution was diluted 100 times (weight ratio) with ion-exchanged water to prepare a test solution. A disc-shaped aluminum alloy substrate was ground on both sides simultaneously using the prepared test solution. The zeta potential of the grinding sludge generated during grinding was measured with ELS-6000 manufactured by Otsuka Electronics Co., Ltd. The zeta potential is preferably −50 mV or less.
Measurement conditions: Measurement cell type (ELS standard cell) Solvent refractive index (1.3312) Measurement temperature (25 ° C)

(Whetstone dirt)
A working solution was diluted 100 times (weight ratio) with ion-exchanged water to prepare a test solution. A disk-shaped aluminum alloy substrate was ground on both sides simultaneously using a test liquid and a grindstone. A PVA grindstone was used as the grindstone. As the aluminum alloy, KS5D86 (manufactured by Kobe Steel) was used.
Evaluation was made on the clogging that occurs entirely on the substrate contact surface of the grindstone during grinding.
◎; No overall clogging occurred;
○: Overall clogging occurred slightly and the grinding efficiency was slightly reduced, but there was no practical problem;
Δ: Overall clogging occurred relatively quickly, grinding efficiency was reduced, and there was a problem in practical use;
X: Overall clogging occurred early.

(Local clogging)
The disk-shaped aluminum alloy substrate was ground on both sides simultaneously by the same method as that for grindstone dirt.
The clogging that occurs locally on the substrate contact surface of the grindstone during grinding was evaluated.
A: No local clogging occurred. ;
○: Local clogging occurred slightly, but there was no practical problem;
Δ: Local clogging occurred relatively frequently, causing problems in practical use;
X: Many local clogging occurred.
It was revealed that local clogging can be effectively prevented when the zeta potential is −50 mV or less.

(scratch)
The disk-shaped aluminum alloy substrate was ground on both sides simultaneously by the same method as that for grindstone dirt.
Scratches (scratches) caused by grinding sludge and dropped abrasive grains on the substrate cutting surface during grinding were evaluated.
◎; no scratches occurred;
○: Scratch occurred slightly, but there was no practical problem;
Δ: Scratches occurred relatively frequently, causing practical problems;
X: Scratches frequently occurred.

(Storage stability)
The working fluid was stored as it was, and the appearance and its change with time were evaluated.
A: Uniform and transparent with little change in appearance over time;
◯: Uniform and transparent at the initial stage of production, with some changes in appearance over time, but no problem in practical use;
Δ: Uniform and transparent at the initial stage of preparation, but there was a problem in practical use because of a large change in appearance over time;
X: There was an appearance defect from the initial stage of preparation.

Hereinafter, “%” means “% by weight”.
Lunac OA (manufactured by Kao Corporation): oleic acid 75%, palmitoleic acid 6%, linoleic acid 6%, palmitic acid 5%, myristic acid 3%, myristoleic acid 3%, stearic acid 1%, linolenic acid 1%.
Tall oil fatty acid; oleic acid 69%, rosin 29%, unsaponifiable 2%.
C10 saturated aliphatic monocarboxylic acid diacid 1550 (manufactured by Harima Chemicals); 8- (5-carboxy-4-hexyl-2-cyclohexen-1-yl) octanoic acid.
Nonionic active agent A; POEO block polymer, PO (6) EO (4), weight average molecular weight 2800.
Nonionic activator B; POE (5) alkyl ether, alkyl group; C12 secondary.
Nonionic activator C; nonylphenol EOPO, EO (9.5) PO (6).

  The machining fluid of the present invention is useful as a lubricant and a cleaning agent used for grinding a workpiece of aluminum or an alloy thereof or after machining.

Claims (7)

(A) 2 to 15% by weight of a monocarboxylic acid having 12 to 18 carbon atoms;
(B) 3-15% by weight of an alicyclic dicarboxylic acid;
(C) an equivalent amount or more required for neutralization of the monocarboxylic acid (A) and the alicyclic dicarboxylic acid (B) with a water-soluble amine; and (D) containing 15% by weight or more of a nonionic surfactant ,
The nonionic surfactant (D) is represented by the general formula (d1);
_{HO (CH 2 CH 2 O)} p1 - (CH 2 CH (CH 3) O) p2 - (CH 2 CH (C 2 H 5) O) p3 -H (d1)
[In the general formula (d1), p1 is 1 or more, and p2 and p3 are each independently 0 or more], a polyoxyalkylene represented by the general formula (d2);
^{_{R 7 O (CH 2 CH 2}} O) n1 - (CH 2 CH (CH 3) O) n2 - (CH 2 CH (C 2 H 5) O) n3 -H (d2)
[In general formula (d2), R ⁷ is an alkyl group having 8 to 18 carbon atoms; n1 is 1 or more, and n2 and n3 are each independently 0 or more] Ethers and general formula (d3);
^{_{R 8 -Ph-O (CH 2}} CH 2 O) m1 - (CH 2 CH (CH 3) O) m2 - (CH 2 CH (C 2 H 5) O) m3 -H (d3)
[In General Formula (d3), R ⁸ is an alkyl group having 6 to 10 carbon atoms; Ph is a phenylene group; m1 is 1 or more, and m2 and m3 are each independently 0 or more] A grinding fluid for aluminum or an alloy thereof, wherein the grinding fluid is at least one compound selected from the polyoxyalkylene alkylphenyl ethers represented .   The grinding fluid for aluminum or its alloy according to claim 1, wherein the monocarboxylic acid (A) contains at least an unsaturated aliphatic monocarboxylic acid.   The grinding fluid for aluminum or its alloy according to claim 1 or 2, wherein the alicyclic dicarboxylic acid (B) is a cycloolefin dicarboxylic acid.   The water-soluble amine (C) is an alkanolamine. The grinding fluid for aluminum or an alloy thereof according to any one of claims 1 to 3. The content of the nonionic surfactant (D) is 30 to 50% by weight . The grinding fluid for aluminum or an alloy thereof according to any one of claims 1 to 4.   The grinding fluid for aluminum or an alloy thereof according to any one of claims 1 to 5, wherein the grinding fluid is diluted with water by 20 to 1000 times on a weight basis. The grinding fluid for aluminum or its alloy according to any one of claims 1 to 6, wherein the nonionic surfactant (D) contains at least polyoxyalkylene and polyoxyalkylene alkyl ether.