JP2600029B2 - Epoxy resin composition suitable for carbon dioxide laser printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates are used in the insulating coating of the electric and electronic components, carbon dioxide laser (hereinafter, CO of ₂ laser) capable of performing clear printing on the insulating coating surface by the irradiation of the CO ₂ The present invention relates to an epoxy resin composition suitable for laser printing.

[0002]

2. Description of the Related Art Conventionally, thermosetting inks and ultraviolet curable inks have been used for printing on electrical and electronic parts insulated with an epoxy resin composition to clearly indicate 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 responding to this, a printing system using laser irradiation has attracted attention. In this laser printing system, the parts irradiated with laser in the form of letters or patterns are discolored by thermal energy, or the irradiated parts are sublimated and the surface is roughened, and letters and patterns can be identified by scattering of light. The printing time of this method is 0.01 second or less, which is much shorter than the conventional heat or ultraviolet curable ink which requires several minutes to several tens of minutes for curing.

However, when a conventional insulating coating of an epoxy resin composition is irradiated with a laser, the surface of the coating is simply roughened, discoloration does not occur, and clear characters and patterns cannot be printed.

Recently, it has been found that when a conventional epoxy resin composition contains yellow ferric hydroxide, the color changes from yellow to brown by laser irradiation (Japanese Patent Laid-Open No. Sho 62-50360).
No.).

Since ferric hydroxide is yellow, it can be used only for a hue such as yellow or orange. However, by using basic copper carbonate or basic lead carbonate, a blue or green base, especially It became possible to apply black laser printing on a light-colored base.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been studied intensively to obtain a resin composition which changes color with lower energy CO ₂ laser light. It has been found that the addition of a fine filler having an average particle size of 10 μm or less can clearly change the color even with low-energy CO ₂ laser light, which had a low degree of color change in the past. The invention has been completed.

It is an object of the present invention to provide a low energy C without deteriorating electrical and other characteristics.
An object of the present invention is to provide an epoxy resin composition which gives a cured product capable of giving a clear print on a resin surface by irradiation even with O ₂ laser light.

[0009]

SUMMARY OF THE INVENTION The present invention provides a CO ₂ laser printing method characterized by containing, in addition to a laser coloring material such as copper (II) oxalate, a fine filler having an average particle size of 10 μm or less. The present invention relates to an epoxy resin composition suitable for:

The epoxy resin composition of the present invention has an average particle size of 10
The reason why a fine filler having a size of not more than μm is used will be described below in the case where copper oxalate is used as a coloring material. Copper (II) oxalate is a pale blue powder that can be heated to 200-300
Decarboxylates at ℃ and changes to copper (II) oxide and turns black.

Therefore, when the epoxy resin composition containing copper (II) oxalate 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 the copper oxalate contained in the resin is heated. (II) undergoes the above chemical reaction and turns black. At this time, if the resin composition contains a fine filler having an average particle diameter of 10 μm or less, it has an effect of promoting the dispersion of the laser coloring material such as copper oxalate (II). Can be dispersed with a laser coloring material. That is, characters and patterns can be clearly printed even with low energy CO ₂ laser light.

The particle size of the coloring material such as copper oxalate (II) used in the present invention is preferably an average particle size of 100 μm or less. The reason is that when the coloring material is mixed and dispersed in the epoxy resin composition, if the average particle diameter is 100 μm or more, when coated on an electronic / electric part, the surface becomes spot-like, which not only reduces the commercial value of the part, but also reduces the dispersion. When laser irradiation is performed, discoloration does not occur in portions where no coloring material is present, and characters and patterns may be cut off to make clear printing impossible.

The average particle size is suitably determined by weight-averaging the particle size distribution obtained with a Coulter counter (manufactured by Nikkaki Co., Ltd.), but may also be determined by a measuring method other than the Coulter counter. Good.

The content of the coloring material is preferably 0.5 to 20% by weight. The reason is that when the content is 0.5% by weight or less, the degree of discoloration is small even when irradiated with a laser, and clear printing is not obtained. On the other hand, if the content exceeds 20% by weight, the electrical insulation of the resin composition is reduced, and it is difficult to satisfy the original performance as an insulating material for electronic and electrical parts.

The epoxy resin used in the present invention is, for example, a diglycidyl ether type epoxy resin such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, a phenol novolak type epoxy resin, a novolak type epoxy resin such as cresol novolak type epoxy resin. Examples thereof include, but are not limited to, resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, linear aliphatic type epoxy resins, elementary ring type epoxy resins, and halogenated epoxy resins.

The curing agent and curing accelerator used in the present invention include acid anhydrides, polyamines, novolak type phenol resins, tertiary amines, imidazole compounds and the like, and any of them may be used. As the inorganic filler, those having an average particle size of 10 μm or less, for example, zircon powder, talc powder, crystalline silica powder, fused silica powder, calcium carbonate powder, magnesia powder, calcium silicate powder, hydrated alumina powder, alumina powder And the like.

In the case of copper (II) oxalate, the resin composition obtained by the present invention usually exhibits a light blue color depending on the color tone, but a pigment such as red, blue, green, black or white may be used in combination.
The resin composition of the present invention may be in any state such as a liquid state such as a casting material, a powder state such as a powder coating, a granular state such as a molding material, and a lump.

As a method of producing the epoxy resin composition of the present invention, for example, in the case of a powder coating, a raw material component weighed at a predetermined ratio is sufficiently mixed by a mixer, and then mixed with an extruder, a co-kneader or a roll. There is a method of melt-kneading and then pulverizing with a pulverizer. Examples of a method for performing insulation coating of electronic / electric parts with the powder coating obtained by the above method include general powders such as a fluid immersion method, an electrostatic fluid immersion method, a rolling method, a sprinkling method, a hot spray method, and an electrostatic spray method. A body painting method is used.

Also, casting materials and molding materials can be manufactured by known techniques and used as insulating materials.

[0020]

Next, the present invention will be described in more detail with reference to examples.

Example 1 Bisphenol A type epoxy resin (epoxy equivalent: 950) 50 parts by weight Copper (II) oxalate (average particle size 15 μm) 5 parts by weight Calcium carbonate powder (average particle size 7 μm) 50 parts by weight 2-methylimidazole 1 part by weight The above composition was blended, blended with a Henschel mixer, melt-kneaded with a co-kneader, and then pulverized with a pulverizer to obtain a powder coating of an epoxy resin composition having an average particle size of 60 to 70 μm.

Example 2 A powder coating of an epoxy resin composition having an average particle size of 60 to 70 μm was prepared in the same manner as in Example 1, except that the inorganic filler was changed to calcium carbonate powder (average particle size: 8 μm). Obtained.

Comparative Example 1 A powder coating of an epoxy resin composition having an average particle size of 60 to 70 μm was prepared in the same manner as in Example 1 except that the inorganic filler was changed to calcium carbonate powder (average particle size: 17 μm). Obtained.

Comparative Example 2 A powder coating of an epoxy resin composition having an average particle diameter of 60 to 70 μm was prepared in the same manner as in Example 1 except that the inorganic filler was changed to calcium carbonate powder (average particle diameter: 30 μm). Obtained.

The resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2 were cured at 100 ° C. for 2 hours. Using a carbon dioxide laser (Ushio Inc. 400 type laser mark, energy density 4 Joule / cm ² and 6 Joule / cm ² ), the sample is irradiated with a laser through a predetermined mask for 1 / 1,000,000 second for curing. The surface of the object was marked. The insulation coating voltage of the cured product was measured according to JIS K 6911. Table 1 shows the results.

[0026]

[Table 1]

[0027]

According to the present invention, when the epoxy resin composition suitable for laser printing according to the present invention is used as an insulating coating material, the surface of the resin can be sharpened by irradiating a low-energy laser without deteriorating electrical characteristics and other characteristics. And a coating that can be applied to the printing. Therefore, since printing can be performed in a much shorter time than in the past, the production process of electric and electronic components can be rationalized.

Claims (2)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin, a curing agent, a filler, and the like, having a laser coloring material such as copper (II) oxalate, and the filler having an average particle size of 10 μm or less. An epoxy resin composition, characterized in that: 2. Copper (II) oxalate is added to the composition in an amount of 0,1%.
The epoxy resin composition according to claim 1, wherein the epoxy resin composition is contained in an amount of 5 to 20 parts by weight.