JPH0618987B2 - Epoxy resin composition for laser printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for an insulating coating of electric and electronic parts, and an epoxy resin for laser printing capable of sharply printing on the surface of the insulating coating by laser irradiation. It relates to a composition.

[Conventional technology]

Conventionally, a thermosetting ink or an ultraviolet curable ink is used for printing on an electric / electronic component insulating-coated with an epoxy resin composition in order to clearly indicate the characteristics and model number, but the purpose is to rationalize the process. As a result, there is a demand for a method capable of printing in a shorter time.

As one of the countermeasures against this, a printing system using laser irradiation is drawing attention. In this laser marking system, the part irradiated with laser in characters or patterns is discolored by heat energy, or the irradiated part is sublimated and surface roughened, and characters or patterns can be identified by scattering of light. , The printing time of this method is 0.0
The time is 1 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 was irradiated with a laser, the coating surface was simply roughened, discoloration did not occur, and clear characters or patterns could not 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 (JP-A-62-50360).
Issue).

However, since ferric hydroxide is yellow, it can be used only for hues such as yellow and orange, and a blue or green substrate,
Especially, it is possible to apply black laser printing on a light-colored base,
It has been regarded as a future issue.

[Problems to be Solved by the Invention]

The present invention, as a result of earnestly studying to obtain a resin composition that changes from blue or green bright color to black color by laser, which was not possible in the past, as a result of irradiation with laser when copper (II) oxalate was contained. We found that the color changed from pale blue to black,
Further, 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.

[Means for Solving the Problems]

The present invention relates to an epoxy resin composition for laser printing, which contains copper (II) oxalate.

The reason why copper (II) oxalate is used in the epoxy resin composition of the present invention will be described below.

Copper (II) oxalate is a light blue powder, and when heated, it becomes 2
It is decarbonated at 00 to 300 ° C and changes to copper (II) oxide, which turns black.

Therefore, when a laser is irradiated in a letter or pattern on an epoxy resin composition containing copper (II) oxalate, the resin surface is heated by the thermal energy of the laser, and copper (II) oxalate contained in the resin is heated. Causes the above chemical reaction and becomes black. That is, only the portion irradiated by the laser becomes black, and the non-irradiated portion remains light blue, so that black characters or patterns can be clearly printed on the light blue base.

The average particle size of copper (II) oxalate used in the present invention is preferably 100 μm or less. The reason for this is that when copper (II) oxalate is mixed and dispersed in an epoxy resin composition, when the average particle diameter is 100 μm or more, the surface of the electronic and electrical parts becomes speckled when coated, which not only reduces the commercial value of the parts. However, the dispersion is likely to be insufficient, and when laser irradiation is performed, discoloration does not occur in a portion where copper (II) oxalate is not present, and characters or patterns may be broken and clear printing may not be possible.

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 copper (II) oxalate is 0.5 to 20% by weight
Is preferred. The reason for this is that if the content is 0.5 wt% or less, the degree of discoloration even when irradiated with laser is small and clear printing cannot be performed, while if it exceeds 20 wt%, the electrical insulation of the resin composition is This is because it is difficult to satisfy the original performance as an insulating material for electronic and electrical 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, novolac type epoxy resins such as cresol novolac type epoxy resins, and glycidyl. Examples thereof include, but are not limited to, ester type epoxy resins, glycidyl amine type epoxy resins, linear aliphatic type epoxy resins, ring-containing epoxy resins, halogenated epoxy resins and the like.

As the curing agent and curing accelerator used in the present invention,
Acid anhydride, polyamine, novolac type phenol resin,
There are tertiary amines, imidazole compounds and the like, but 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 by the present invention usually exhibits a light blue color due to the color tone of copper (II) oxalate, but pigments such as red, blue, green, black and white may be used in combination.

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, in the case of powder coating, after thoroughly mixing the raw material components weighed at a predetermined ratio with a mixer, melt kneading with an extruder, a co-kneader or a roll, Then, there is a method of crushing with a crusher. As a method for performing insulation coating of electronic and electrical parts with the powder coating obtained by the above method, a fluidized immersion method, an electrostatic fluidized immersion method, a rolling method,
A general powder coating method such as a sprinkling method, a hot spray method, or an electrostatic spray method is used.

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.

〔Example〕

 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 Crystalline silica powder 50 parts by weight 2 Methylimidazole 1 part by weight The above composition was blended, After blending with a Henschel mixer, melt-kneading with a cokneader, and pulverizing with a pulverizer, a powder coating material of an epoxy resin composition having an average particle diameter of 60 to 70 μm was obtained.

Example 2 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 copper (II) oxalate was changed to 20 parts by weight.

Comparative Example 1 In Example 1, the addition amount of copper (II) oxalate was 0.1.
The average particle diameter is 60 to 70 μm in the same manner except that the weight part is replaced.
A powder coating material of the epoxy resin composition was obtained.

Comparative Example 2 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 copper (II) oxalate was changed to 50 parts by weight.

Cured products were prepared from the resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2.

Carbon dioxide gas laser (USHIO INC. 40
A 0 type laser mark, energy density 6 Joule / cm ² ) was used to irradiate a laser through a predetermined mask for 1 / million seconds to mark the surface of the cured product.

The insulation coating voltage of the cured product was measured according to JIS K6911. The results are shown in Table-1.

[Effects of the Invention] When the laser-printing epoxy resin composition of the present invention is used as an insulating coating material, it is possible to perform clear printing on the resin surface by laser irradiation without deteriorating 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 and electronic parts can be rationalized.

Claims (3)

[Claims] 1. An epoxy resin composition for laser printing, comprising an epoxy resin, a curing agent, a filler and the like, and containing copper (II) oxalate. 2. The average particle size of copper (II) oxalate is 100 μm.
The epoxy resin composition for laser printing according to claim 1, wherein: 3. Copper (II) oxalate is added to the composition in an amount of 0.5.
3 to 20% by weight is contained.
The epoxy resin composition for laser printing as described above.