JP6401100B2 - Ink for coloring inspection used for impact inspection - Google Patents

Description

  The present invention relates to a color inspection ink, and more particularly to a color inspection ink used for impact inspection.

  In recent years, a hard disk drive (HDD) has been used not only as a personal computer recording device but also as a large-capacity storage for various devices such as a television recording device, an in-vehicle navigator, and a server. In order to cope with digital information that continues to increase in the future, it is indispensable to increase the capacity of HDDs.

  Increasing the capacity of HDDs increases the recording density of magnetic disks, and the distance between the magnetic recording surface and the magnetic head becomes narrower. The magnetic head may touch the hard disk due to an impact, and the hard disk may be damaged. . Such scratches on the hard disk can cause major damage to the equipment that uses the hard disk and cannot continue to be used. Therefore, it is inspected whether or not the hard disk is damaged by a shock that can normally occur, and the presence or absence of toughness that does not cause the damage is examined.

  The toughness inspection of a hard disk is currently mainly performed by a collision test between the hard disk carriage and the hard disk surface. Conventionally, the lipstick is applied to the surface of the hard disk carriage facing the hard disk. However, with this method, even if the coating is uniformly applied in a partly large amount, or even if it is applied to the same thickness, uneven coating may occur, and it is difficult to apply uniformly. Lipstick has a certain degree of softness and has the advantage that it can be marked reliably when it comes in contact with an impact, but although it has the softness of a crayon, it can be applied uniformly with a highly viscous liquid at room temperature. very difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a coloring material that can replace a lipstick and has a performance that can be uniformly applied to a hard disk carriage while maintaining a certain degree of softness of color transfer upon contact.

  That is, the present invention provides a color inspection ink containing a tackifier, a wax, a transfer agent, a plasticizer, a colorant, and a solvent.

  The wax is preferably carnauba wax.

  The tackifier is preferably an aromatic modified terpene resin.

  The transferability-imparting agent is preferably a microcrystalline wax.

  The plasticizer is preferably mineral oil.

  The solvent is preferably a combination of toluene and methyl ethyl ketone.

  The ink for color inspection of the present invention has a tackifier of 3.0 to 20.0% by weight, a wax of 1.0 to 9.5% by weight, and a transfer agent of 3.0 to 6 based on the total weight. It is preferably contained in an amount of 0.0% by weight, plasticizer 5.0 to 19.0% by weight, colorant 5.0 to 20.0% by weight and solvent 36.0 to 72.0% by weight.

  Unlike the highly viscous liquid lipstick, the color inspection ink of the present invention is a low-viscosity liquid, and can be applied by various methods in any place, and the application marks at the time of application disappear immediately. And uniform coating can be formed. Immediately after coating, the coating is dried to form a colored film, and has a capability of easily transferring the colored film to an impact object in a collision test. Therefore, the color inspection ink of the present invention can be used for impact inspection of a machine with movement, and is not limited to a hard disk, and can be used in a camera, a watch, a printer, an automobile engine (not heated), etc. it can.

  The ink for color inspection of the present invention is characterized by containing a tackifier, a wax, a transfer agent, a plasticizer, a colorant, and a solvent.

  The tackifier added to the ink for color inspection of the present invention imparts moderate tackiness to the ink, and imparts tackiness by blending with wax and other polymers. Terpene resin, aromatic modified terpene resin, rosin modified phenol resin, alkylphenol resin, terpene phenol resin and the like. Of these, aromatic modified terpene resins are most preferred.

  The tackifier can be blended in an amount of 3.0 to 20.0% by weight, preferably 5.0 to 15.0% by weight, based on the total amount of the color inspection ink of the present invention. If it exceeds 20.0% by weight, stickiness remains after drying, and if it is less than 3.0% by weight, it will not be transferred even if there is a collision.

  The wax to be blended in the color inspection ink of the present invention needs to have an appropriate hardness, softness, and transferability. Wax and petroleum-based polyethylene wax are used. Of these, carnauba wax is most preferred.

  The amount of the wax added to the color inspection ink of the present invention is 1.0 to 9.5% by weight, preferably 1.0 to 8.0% by weight. If the wax is less than 1% by weight, an appropriate hardness cannot be obtained, and if it exceeds 9.5% by weight, no transfer occurs even if there is a collision.

  The transferability-imparting agent blended in the color inspection ink of the present invention assists the transferability of the wax and is considered to be a wax itself, but has a higher transferability, such as a microcrystalline wax and an α-olefin oxide. Can be illustrated. Of these, microcrystalline wax is most preferred.

  The transferability-imparting agent is added in an amount of 3.0 to 6.0% by weight based on the total amount of the color inspection ink of the present invention. If the transferability-imparting agent is less than 3.0% by weight, it does not transfer even if there is a collision, and if it is added in excess of 6.0% by weight, the coating amount increases so that a coating pattern remains at the time of coating.

  The plasticizer blended in the color inspection ink of the present invention has an action of plasticizing the above waxes, and specifically includes mineral oil, vegetable oil, surfactant and the like. Of these, mineral oil is most preferred.

  The plasticizer is blended in an amount of 5.0 to 19.0% by weight, preferably 8.0 to 18.0% by weight, based on the total amount of the color inspection ink of the present invention. When the plasticizer is less than 5.0% by weight, it is difficult to record an instantaneous impact. Conversely, when the amount exceeds 19.0% by weight, the color inspection ink becomes soft, and even if the impact is recorded, it is buried over time. Will occur.

  The colorant used in the color inspection ink of the present invention is not particularly limited, and any colorant may be used as long as it is used for coloring a wax-based composition. Carbon black, carmine red, titanium white, etc.) and dyes (for example, oil-soluble dyes, nigrosine, etc.). Preferably, carbon black, carmine red, and titanium white are suitable under any light source, and are easy to find a part peeled off by impact even when applied to a metallic glossy surface.

  The colorant is blended in an amount of 5.0 to 20.0% by weight, preferably 7.0 to 15.0% by weight, based on the total amount of the color inspection ink of the present invention. If the colorant is less than 5.0% by weight, the colorability is insufficient and the presence or absence of transfer cannot be determined. On the other hand, when the colorant is more than 20.0% by weight, the colorant becomes too much, the coating property is deteriorated, and the finish is not smooth.

  The solvent used in the color inspection ink of the present invention needs to have the above-mentioned materials having a suitable viscosity with good coatability and at the same time have good drying properties after coating. Specifically, various alcohols (eg, methanol, ethanol, propanol, etc.), aromatic solvents (eg, benzene, toluene, xylene, etc.), ketones (eg, dimethyl ketone, diethyl ketone, methyl ethyl ketone, etc.), ethers (For example, dimethyl ether, methyl ethyl ether, diethyl ether, dipropyl ether, etc.) and esters (for example, methyl acetate, ethyl acetate, propyl acetate, etc.) can be used. Of these, aromatic solvents (particularly toluene) and ketones (particularly methyl ethyl ketone) are more preferred because the coating film needs to have a uniform thickness after drying.

  The amount of the solvent added to the ink for color inspection is 36.0 to 72.0% by weight, preferably 42.0 to 66.0% by weight. When the amount of the solvent is less than 36.0% by weight, the viscosity of the color inspection ink becomes high and sufficient coatability cannot be obtained. On the contrary, if the amount of the solvent is more than 72.0% by weight, the viscosity of the color inspection ink is too low to obtain a predetermined coating amount.

  In addition to the above, the color inspection ink of the present invention may contain a dispersant. The dispersant is used to increase the dispersibility of the pigment to improve the color development and prevent aggregation. Specifically, the polycarboxylic acid partial amide, the amino group-containing polyester, and the fatty acid ester surfactant. And olefin-based activators. Of these, polycarboxylic acid partial amides are most preferred.

  The dispersant may be blended in an amount of 0.3 to 6.0% by weight, preferably 0.5 to 2.0% by weight, based on the total amount of the color inspection ink of the present invention. If the dispersant is less than 0.3% by weight, it has a drawback of agglomeration, and if it is more than 6.0% by weight, the transferability is deteriorated.

  The color inspection ink of the present invention is formed by mixing the above components. Mixing is performed by a normal method, and specifically, using a disper, a homogenizer, a shaker, or an attritor. The mixing time is not particularly limited as long as mixing is performed uniformly, and varies depending on the mixing apparatus to be used. For example, when a shaker is used, 30 minutes to 4 hours, preferably 1 to 3 hours are preferable.

  The color inspection ink of the present invention is applied onto a hard disk carriage by an ordinary method such as brush coating, bar coater, spraying or the like. In the present invention, a color inspection film having a uniform film thickness is formed on a hard disk carriage by simply applying it by brushing. The film thickness of the color inspection film is preferably 30 to 65 μm, more preferably 30 to 60 μm, and most preferably 45 to 55 μm.

  The present invention will be described in more detail with reference to examples. The present invention should not be construed as being limited by these examples.

Example 1
Aromatic modified terpene resin 6 parts by weight (8.53% by weight), carnauba wax 1 part by weight (1.42% by weight), microcrystalline wax 2 parts by weight (2.84% by weight), mineral 8 parts by weight (11.37% by weight) of oil, 5 parts by weight (7.11% by weight) of carbon black, 0.3 part by weight (0.42% by weight) of polyvalent carboxylic acid partial amide as a dispersant, toluene 36 An ink for color inspection was prepared by mixing 2 parts by weight (41.20% by weight) and 12 parts by weight (17.06% by weight) of methyl ethyl ketone using a shaker for 2 hours. The viscosity of the ink was 40 mPa · S, and the volatile content was 68% by weight.

  About the obtained color inspection ink, as described below, wettability, surface condition (surface roughness, separation condition), thickness after spreading, hardness after scribing, color unevenness, transferability, hardness and A comprehensive evaluation was performed. The results are shown in Table 1.

For wettability , one drop of ink is dropped on a hard disk, and after drying, the spread width of the ink is measured by diameter (mm).

Surface roughness of the surface state The surface roughness is measured with a laser microscope manufactured by Mitaka Kogyo Co., Ltd.

The ink is dropped with a surface-like separation state spoid, and the separation state of the oil and the colorant in the ink is visually observed at the end.

Thickness after spreading The thickness after spreading is measured with a laser microscope manufactured by Mitaka Kogyo Co., Ltd.

Color unevenness This ink was applied to a substrate by brushing, dried at 25 ° C. (room temperature) for 3 hours, and then the color unevenness of the colored film was visually observed. Evaluation was performed as follows. The results are shown in Table 1.
○… The concentration is uniform.
Δ: Dense and thin, but partially appears.
X: Dense and thin, but clearly appears.

Transferability Next, the impact test under the conditions of contacting the ink surface by its own weight with 13gf torque screwdriver was observed transferability of the ink. Evaluation of transferability was performed as follows. The results are shown in Table 1.
○: The ink is transferred and the transfer marks are clearly visible.
Δ: The ink is transferred, and the transfer mark is partial.
X: Not transferred.

Hardness after scribing Further, the hardness of the colored film was measured by scribing with a syringe needle. They were evaluated according to the following criteria.
○: The mark does not change even after an arbitrary time.
Δ: Soft and narrow marks. Or it is hard and the edge part is a little chipped.
×: Soft marks are buried. Or it is hard and the edge part is missing.

Comprehensive evaluation The above color unevenness, transferability and hardness were comprehensively evaluated according to the following criteria. The results are shown in Table 1.
A: There is no color unevenness, transferability is good, and the applied colored film has an arbitrary hardness.
Δ: Color unevenness and transferability are good or partially good, but the applied colored film is out of any hardness.
X: There is uneven color, transferability is poor, and the applied colored film is out of any hardness.

Examples 2-6 and Comparative Examples 1-2
A color inspection ink was prepared in the same manner as in Example 1 using the formulation shown in Table 1. The viscosity and volatile concentration of the ink are listed in Table 1. Moreover, the same evaluation as Example 1 was performed. The results are shown in Table 1.

  The color inspection inks of the examples all have no color unevenness, good transferability, and good hardness. Therefore, comprehensive evaluation is also excellent. In Example 4, the wax component carnauba wax was used in an amount of 9.80% by weight. The amount of carnauba wax is large and the hardness is not sufficient. In Example 5, since mineral oil as a plasticizer is used in an amount of 19.50% by weight, evaluation of gloss, surface condition, and separation is good, but color unevenness occurs and the finished coating film is soft. Because of this, the line marks fill up with time in the scribing test. In Example 6, the colorant is used in an amount of 31.70% by weight. Color unevenness, gloss, and surface condition are evaluated well, but separation is observed, the finished coating film is soft, and the marking lines are filled with time and become narrower than the original interval. Comparative Example 1 is a formulation that does not use microcrystalline wax and has good evaluation of smoothness, separation, and color unevenness, but poor transfer performance. In addition, when microcrystalline wax is not used, the ink viscosity increases when it is allowed to stand for 1 day, and the wettability and the surface condition are significantly deteriorated. Compared to other examples, it is considered that the microcrystalline wax exhibits the performance of stabilizing the fluidity of the ink as well as the transferability. Comparative Example 2 is an example in which no carnauba wax is used, and the color hardness and the hardness after scuffing are poor, making it difficult to actually use.

  The ink for color inspection of the present invention is an ink that is applied to the surface of a carriage for a hard disk in order to detect the presence or absence of an impact scratch that can be used in an impact resistance test of a hard disk drive (HDD). Used when testing the impact resistance of a drive (HDD).

Claims (2)

Relative to the total weight of the colored test inks used in the impact test, tackifier 3.0 to 20.0% by weight is an aromatic modified terpene resin, carnauba wax 1.0 to 9.5 wt%, microcrystalline Transferability imparting agent 3.0 to 6.0% by weight as a wax, plasticizer 5.0 to 19.0% by weight, a colorant 5.0 to 20.0% by weight, and a solvent 36.0% as a mineral oil. Ink for coloring inspection used for impact inspection , contained in an amount of 72.0% by weight. The color inspection ink used for impact inspection according to claim 1, wherein the solvent is a combination of toluene and methyl ethyl ketone.