JPH06305258A - Epoxy resin composition suitable for laser printing - Google Patents

Abstract

PURPOSE:To enable clear printing without deteriorating electric properties of an epoxy resin compound which is used for an insulating film of electric and electronic parts and enables laser beam printing on a surface coated with the film by incorporating nickel lactate into the compound. CONSTITUTION:Nickel lactate with an average particle size 100mum or less is incorporated in an epoxy resin composition comprising epoxy resin, a curing agent, and filler in a ratio of 0.5-20wt.% to the composition. The nickel lactate, light green powder, is decomposed when heated at 200 300 deg.C, turning black. When a character or a pattern on the surface of the epoxy resin composition containing the nickel lactate is irradiated with a laser beam, the surface is heated by the laser beam to turn the nickel lactate black so that the character or the pattern is printed clearly.

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 suitable for laser printing, which is used for insulating coating of electric / electronic parts and is capable of sharply marking the surface of the insulating coating by laser irradiation. Is.

[0002]

2. Description of the Related Art Conventionally, a thermosetting ink or an ultraviolet curable ink has been used for printing on an electric / electronic component insulating-coated with an epoxy resin composition to clearly indicate a characteristic or a model number. However, there has been a demand for a method that can print in a shorter time for the purpose of streamlining the process. As one of the countermeasures against this, a printing system using laser irradiation is drawing attention. In this laser printing system, the part irradiated with laser in the form of letters or patterns is discolored by thermal energy, or the part exposed is sublimed and surface roughened, and letters or patterns can be identified by scattering of light. is there. The printing time of this method is 0.01 second or less, which is significantly shorter than the conventional heat-curable or ultraviolet-curable ink which requires several minutes to several tens of minutes for curing. However, when the insulating coating of the conventional epoxy resin composition is irradiated with a laser, discoloration does not occur simply by roughening the coating surface, and clear characters or patterns cannot be printed.

Recently, it has been found that when a conventional epoxy resin composition contains yellow ferric hydroxide, it is discolored from yellow to brown by laser irradiation (JP-A-62-62).
50360). However, since ferric hydroxide is yellow, it can be used only for hues such as yellow and orange, and it is a future task to apply black laser printing to blue or green substrates, especially light-colored substrates. Has been said.

[0004]

DISCLOSURE OF THE INVENTION In the present invention, as a result of earnestly studying to obtain a resin composition in which a blue or green bright color, which has been impossible in the past, is discolored into a black color by a laser is studied, nickel (II) lactate It has been found that when it is contained, it changes color from light green to black when irradiated with a laser, and based on this finding, various studies have been advanced to complete the present invention. An object of the present invention is to provide an epoxy resin composition which gives a cured product capable of sharply marking a resin surface by laser irradiation without deteriorating electrical properties and other properties. is there.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an epoxy resin composition suitable for laser printing, which contains nickel (II) lactate. The reason why nickel (II) lactate is used in the epoxy resin composition of the present invention will be described below. Nickel (II) lactate is a light green powder,
When heated, it decomposes at 200 to 300 ° C. and changes into nickel (II) oxide, resulting in a black color. Therefore, when the epoxy resin composition containing nickel (II) lactate is irradiated with a laser in a letter or pattern, the resin surface is heated by the thermal energy of the laser, and the nickel (II) lactate contained in the resin is A chemical reaction occurs that turns black. That is, only the portion irradiated by the laser becomes black, and the non-irradiated portion remains light green, so that black characters and patterns can be clearly printed on the light green substrate.

The nickel (II) lactate used in the present invention preferably has an average particle size of 100 μm or less. The reason for this is that when nickel (II) lactate is mixed and dispersed in an epoxy resin composition, the surface becomes speckled when coated on electronic / electrical parts with an average particle size of 100 μm or more,
Not only the commercial value of the parts is reduced, but also the dispersion is likely to be insufficient, and when the laser is irradiated, discoloration does not occur in the part where nickel lactate (II) does not exist, and characters and patterns are interrupted, making clear printing possible. It may disappear. The average particle size is appropriately determined by weight-averaging the particle size distribution obtained by a Coulter counter (manufactured by Nikkaki Co., Ltd.), but may be determined by a measuring method other than the Coulter counter. The content of nickel (II) lactate is preferably 0.5 to 20% by weight. The reason for this is that if the content is 0.5% by weight or less, the degree of discoloration is small even when irradiated with laser, so that clear printing cannot be performed, and conversely 20
This is because if the content exceeds 5% by weight, the electrical insulation of the resin composition deteriorates, and it becomes difficult to satisfy the original performance as an insulating material for electronic parts.

Examples of the epoxy resin used in the present invention include diglycidyl ether type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, phenol novolac type epoxy resins, and novolac type epoxy resins such as cresol novolac type epoxy resins. Examples of the resin include, but are not limited to, resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, chain aliphatic type epoxy resins, heterocyclic type epoxy resins and halogenated epoxy resins. Examples of the curing agent and curing accelerator used in the present invention include acid anhydrides, polyamines, novolac type phenolic resins, and
Although there are primary amines, imidazole compounds, etc., any of them may be used. If necessary, known inorganic fillers such as zircon powder, talc powder, crystalline silica powder, fused silica powder, calcium carbonate powder, magnesia powder, calcium silicate powder, hydrated alumina powder, and alumina powder may be added. .

The resin composition obtained according to the present invention usually has a pale yellow color due to the color tone of nickel (II) lactate, but has a red color.
Pigments such as blue, green, black and white may be used together. The resin composition of the present invention may be in any state such as liquid such as casting material, powder such as powder coating material, granule such as molding material and lump. As a method for producing the resin composition of the present invention, for example, when raising the case of powder coating, after thoroughly mixing the raw material components weighed in a predetermined ratio with a mixer, melt kneading with an extruder, a cokneader or a roll, Then, there is a method of crushing with a crusher. As a method for performing insulation coating of electronic / electrical components with the powder coating obtained by the above method, a fluid immersion method, an electrostatic fluid immersion method, a rolling method, a sprinkling method, a hot spray method, an electrostatic spray method, or another general powder. There is a body painting method. Also, in the case of a casting material or a molding material, it can be manufactured by a known technique and can be used as an insulating material.

[0009]

EXAMPLES Next, the present invention will be described in more detail by way of examples. << Example 1 >> Bisphenol A type epoxy resin (epoxy equivalent 950) 50 parts by weight Nickel (II) lactate (average particle size 20 μm) 5 parts by weight Crystalline silica powder 50 parts by weight 2-Methylimidazole 1 part by weight The above composition is blended. Then, they were blended with a Henschel mixer, melt-kneaded with a kneader, and then pulverized with a pulverizer to obtain a powder coating material of an epoxy resin composition having an average particle diameter 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 obtained in the same manner as in Example 1, except that the amount of nickel (II) lactate added was changed to 20 parts by weight. It was << Comparative Example 1 >> A powder coating material of an epoxy resin composition having an average particle diameter of 60 to 70 μm was obtained in the same manner as in Example 1, except that the addition amount of nickel (II) lactate was changed to 0.1 part by weight. . << Comparative Example 2 >> In Example 1, the addition amount of nickel (II) lactate was changed to 50 parts by weight, and the average particle size was 6
A powder coating material of the epoxy resin composition having a thickness of 0 to 70 μm was obtained.

Cured products were prepared from the resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2. A carbon dioxide gas laser (400 type laser mark manufactured by Ushio Denki Co., Ltd., energy: 6 Joule) was applied to this sample by laser irradiation through a predetermined mask for 1,000,000th of a second to mark the surface of the cured product. In addition, the dielectric breakdown voltage of the cured product is measured according to JIS K
6911. The results are shown in Table 1.

[0012]

[Table 1]

[0013]

When the epoxy resin composition suitable for laser marking of the present invention is used as an insulating coating material, a sharp marking can be made on the resin surface by laser irradiation without deteriorating the electrical characteristics and other characteristics. It is possible to provide a coating capable of Therefore, since printing can be performed in a much shorter time than in the past, the production process of electric / electronic parts can be rationalized.

Claims (3)

[Claims] 1. An epoxy resin composition comprising an epoxy resin, a curing agent, a filler, etc., wherein nickel (II) lactate is used.
An epoxy resin composition comprising: 2. The average particle size of nickel (II) lactate is 100.
The epoxy resin composition according to claim 1, which has a thickness of not more than μm. 3. The nickel (II) lactate is contained in an amount of 0.5 to 20 parts by weight based on the composition.
Or the epoxy resin composition according to 2.