JPH1192632A - Epoxy resin composition for laser printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for laser printing, capable of applying vivid black-based printing having durability to resin surface by irradiation of laser without lowering electric characteristics and other characteristics. SOLUTION: This epoxy resin composition for laser printing contains a copper-based compound and a nickel-based compound as a coloring agent by laser irradiation. In the resin composition, it is preferable that the ratio of the copper-based compound to the nickel-based compound is (2/8) to (5/5) and the total compounding amount of both compounds is 1-20 wt.% based on total composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for laser printing which can provide clear printing on the surface of an insulating coating of an electric / electronic component.

[0002]

2. Description of the Related Art Conventionally, thermosetting or ultraviolet-curable inks have been used for printing on electric / electronic parts insulated with an epoxy resin composition to specify characteristics and model numbers. A method capable of printing in a shorter time is required for the purpose of streamlining the process.

[0003] As one of the methods for this, there is a printing system by laser irradiation. In this laser printing system, a portion irradiated with a laser in the form of a character or a pattern is discolored by thermal energy, or the irradiated portion is sublimated and the surface is roughened, so that the character or pattern can be identified by light scattering. The printing time of this method is 0.
01 seconds or less, which is much shorter than the conventional heat or ultraviolet curable ink requiring several minutes to several tens of minutes. However, when a conventional insulating coating of an epoxy resin composition is irradiated with a laser, discoloration does not occur, or simply by roughening the coating surface, the contrast is weak and clear characters or patterns cannot be printed in many cases. For this reason, it is necessary to include a material that changes color by the thermal energy of the laser in the epoxy resin composition.

It has been found that brown letters and patterns can be printed on the coating surface of a yellow background by laser irradiation by blending iron (III) hydroxide with a conventional epoxy resin composition (Japanese Patent No. 1667789). issue). However, since iron (III) hydroxide is also a yellow pigment having a strong hiding power, it can be used only for a hue such as yellow or orange, and its use is limited. Therefore, a method using basic lead phosphite or copper oxalate as a material which is not restricted by such a hue has been proposed (JP-A-2-136288,
JP-A-3-52945. However, lead-based compounds such as basic lead phosphite tend to be avoided because of the recent strong demand for reduction of environmental load. A copper-based compound such as copper oxalate has a disadvantage in that an oxide formed after printing is reduced in an epoxy resin composition using a halogen-based flame retardant in combination, resulting in reduced blackness of characters and patterns. Each material had advantages and disadvantages.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color tone of any hue without deteriorating the electrical characteristics and other characteristics, and to achieve a durability without using a lead compound. An object of the present invention is to provide an epoxy resin composition that can perform laser printing of a certain black color.

[0006]

The present invention contains both a copper-based compound (copper oxalate, basic copper carbonate, etc.) and a nickel-based compound (nickel formate, nickel lactate, etc.) capable of giving black printing. And an epoxy resin composition for laser printing. The reason for using a copper compound and a nickel compound together in the epoxy resin composition of the present invention will be described below.

[0007] The copper-based compound capable of performing black-based printing as described above is decomposed by heating to copper oxide, and changes from blue-based to black-based. Further, the nickel-based compound is also decomposed by heating to nickel oxide, so that the color changes from green to black. In addition, copper-based compounds and nickel-based compounds both have a hue ranging from blue to green, but because of their low hiding power, they limit the hue of the composition like iron (III) hydroxide even when blended in resin. There is nothing to do. Therefore, even if each of the copper-based compound and the nickel-based compound is used alone, when the epoxy resin composition containing these is irradiated with a laser in the form of letters or patterns, the resin surface is heated by the thermal energy of the laser and contained in the resin. The copper-based compound and the nickel-based compound thus reacted cause a black color and a considerably clear print can be obtained.

However, when a copper compound is blended in an epoxy resin composition containing a halogenated compound such as a halogenated aromatic hydrocarbon or a halogenated epoxy resin as a flame retardant, the compound is decomposed by thermal energy of a laser. Oxidation of the copper-based compound does not proceed sufficiently, and on the contrary, it is gradually reduced and metal copper is deposited. This is because, at this time, a strongly reducing hydrogen halide is generated from the halogenated compound which decomposes at the same time, and copper oxide is reduced. Since the copper compound easily reacts with hydrogen halide, it is considered that reduced metallic copper forms a complex. For this reason, a fading phenomenon occurs in which the degree of blackness of the printed characters and patterns is reduced.

Such a reducing action by hydrogen halide acts on any metal compound, but the durability differs because the reactivity with hydrogen halide differs depending on the metal. Nickel-based compounds are listed as non-lead-based metal compounds that are decomposed and oxidized by the thermal energy of a laser to change to a black-based color and are more durable than copper-based compounds.
However, a nickel-based compound is inferior in the initial blackness of a printed character or pattern as compared with a composition containing a copper-based compound or a lead-based compound. For this reason, if the initial blackness is to be increased only by the nickel-based compound, the amount of the compound in the composition must be increased. Generally, such a metal compound to be compounded for laser printing causes a decrease in electric insulation when the compounding amount is too large, so that the compounding amount is limited.

Therefore, the initial blackness of printed characters and patterns is increased by blending a copper-based compound,
In order to make the fading phenomenon of the copper compound inconspicuous, a technique using a durable nickel compound together was studied.
As a result, by using these two in combination, not only when the halogenated compound is not contained as a flame retardant, but also in the epoxy resin composition containing the halogenated compound, the electric characteristics and other various properties are obtained. It has been found that the color can be adjusted to any hue without deteriorating the characteristics and durable black-based laser printing can be performed without using a lead-based compound.

The combined ratio of the copper compound and the nickel compound is preferably copper compound / nickel compound = 2/8 to
5/5. This is a copper compound / nickel compound>
This is because the composition of 5/5 makes the fading phenomenon more conspicuous, and conversely, in the composition of copper compound / nickel compound <2/8, the low initial blackness becomes more conspicuous. The total amount of the copper compound and the nickel compound is preferably 1 to 20% by weight based on the whole composition. When the content is less than 1% by weight, the degree of discoloration is small even when irradiated with a laser, so that clear printing is not achieved.
If the content exceeds 0% by weight, the electrical insulation of the composition is reduced, and it is difficult to satisfy the original performance as an insulating material for electronic parts.

The maximum particle size of the copper compound and the nickel compound used in the present invention is preferably 300 μm or less. This is because when a copper-based compound and a nickel-based compound are mixed and dispersed in a composition, when coated on an electric or electronic component with a maximum particle size exceeding 300 μm, not only does the surface become spot-like and the commercial value of the component is lowered, but also This is because dispersion is likely to be insufficient, and when laser irradiation is performed, discoloration does not occur in portions where the copper-based compound and the nickel-based compound are not present, characters and patterns are cut off, and clear printing may not be possible. The maximum particle size is a weight maximum particle size that can be measured by a general particle size distribution measuring device such as Microtrac (manufactured by Nikkiso) or Coulter Counter (manufactured by Nikkaki). At this time, when the measurement object is water-soluble, it is necessary to perform measurement in a non-aqueous system.

In the present invention, the copper-based compound includes copper oxalate, basic copper carbonate, copper tartrate, copper hydroxide, copper gluconate, and the like. Copper oxalate, basic copper carbonate, and copper tartrate are preferred. . Examples of the nickel-based compound include nickel formate, nickel lactate, nickel carbonate, nickel hydroxide, nickel hypophosphite, and the like, and nickel formate, nickel lactate, and nickel carbonate are preferred.

In the case of printing with a carbon dioxide laser, an epoxy resin composition containing a copper-based compound and a nickel-based compound is used in order to increase the sharpness of the print, and zirconium silicate, calcium sulfite, etc. May be blended. This is because the wavelength of zirconium silicate or calcium sulfite is the wavelength of carbon dioxide laser light.
It absorbs light around 0.6μm well and can be effectively converted to heat energy.
This is because the oxidation reaction can be promoted. However, the amount is preferably 1 to 30% by weight based on the whole composition. If the compounding amount is less than this, no coloring aid is recognized, and if the compounding amount exceeds this, the printed characters and patterns are blurred and the sharpness is rather lost.

The epoxy resin used in the present invention is not particularly limited, such as a diglycidyl ether type epoxy resin such as a bisphenol A type epoxy resin, a novolak type epoxy resin such as a phenol novolak type epoxy resin, and a halogenated epoxy resin. is not. The curing agent and curing accelerator used in the present invention are not particularly limited, such as acid anhydrides, amines and imidazole. If necessary, known inorganic fillers such as silica powder,
Calcium carbonate powder, calcium silicate powder, talc powder, hydrated alumina powder and the like may be blended. Furthermore, the epoxy resin composition obtained according to the present invention presents a blue-based to green-based color depending on the hue of the copper-based compound and the nickel-based compound, but has a low hiding power as described above, so that red, blue,
By mixing pigments such as yellow, white and black, it is possible to achieve various colors.

The epoxy resin composition of the present invention may be in a liquid state such as a casting material, a powder state such as a powder coating, or a granular state such as a molding material. As a production method, for example, when the case of powder coating is raised, a raw material component weighed to a predetermined ratio is sufficiently mixed by a mixer, and then extruded, a kneader, a method of melting and kneading with a roll, and pulverizing with a pulverizer. Etc. Examples of a method of coating the powder coating obtained in this manner on electric / electronic parts include a fluid immersion method, an electrostatic fluid immersion method, a hot spray method, an electrostatic spray method and the like. Casting materials and molding materials can also be manufactured by known techniques and used as insulating materials.

[0017]

Next, the present invention will be described in more detail with reference to examples. In addition to the following raw materials, a predetermined amount of a coloring agent and a coloring aid for laser printing as shown in Table 1 are blended, blended by a mixer, melt-kneaded by an extruder, and then pulverized by a pulverizer. A powder coating of an epoxy resin composition having a particle size of 60 to 70 μm was prepared. The cured product of the powder coating was irradiated with laser light through a mask using a carbon dioxide laser marker (Unimark 610AGH, energy 6J, manufactured by Ushio Inc.), and characters and patterns were printed on the surface of the cured product. At this time, the appearance of the cured product surface, and the initial blackness, durability, and clarity of the printed area are visually observed.
Judgment was made in four stages of ●, ○, △, ×. ● indicates a very high level, ○ indicates a good level, Δ indicates a normal level, and X indicates a slightly inferior level. In order to evaluate the electrical insulation properties of the cured product, the volume resistivity (moisture resistance) after 2 hours of boiling was J
It measured based on IS-K6911. The results are summarized in the lower column of Table 1.

[0018]

[Table 1]

[0019]

When the epoxy resin composition for laser printing of the present invention is used as an insulating coating material, the resin surface can be made clear and durable by laser irradiation without deteriorating the electrical and other properties. System printing can be performed. As a result, the electrical characteristics of electric / electronic parts can be maintained more than before, and high-quality laser printing with high contrast and high durability of characters and patterns becomes possible.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 3/32 C08K 3/32 3/34 3/34 5/098 5/098

Claims (6)

[Claims] 1. An epoxy resin composition for laser printing, comprising a copper-based compound and a nickel-based compound as a color former by laser irradiation. 2. The combined ratio of the copper compound and the nickel compound is copper compound / nickel compound = 2/8 to 5.
The epoxy resin composition according to claim 1, wherein the total amount of the epoxy resin composition is 1 to 20% by weight based on the whole composition. 3. The epoxy resin composition according to claim 1, wherein the maximum particle size of the copper-based compound and the nickel-based compound is 300 μm or less. 4. The epoxy resin composition according to claim 1, wherein the copper-based compound is copper oxalate, basic copper carbonate, copper hydroxide, copper gluconate, or copper tartrate. 5. The epoxy resin composition according to claim 1, wherein the nickel compound is nickel formate, nickel lactate, nickel hydroxide, nickel carbonate, or nickel hypophosphite. 6. The composition according to claim 1, wherein zirconium silicate and / or calcium sulfite is contained in an amount of 1 to 30% by weight based on the whole composition.
Or the epoxy resin composition according to 5.