JPH068380B2 - Epoxy resin composition suitable for carbon dioxide 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 a carbon dioxide laser capable of applying clear carbon dioxide laser irradiation to the surface of the insulating coating. The present invention relates to an epoxy resin composition suitable for printing by.

[Prior Art] Conventionally, a thermosetting ink or an ultraviolet curable ink is used when printing is performed to clearly indicate the characteristics and model number of an electric / electronic component insulating-coated with an epoxy resin composition. A method capable of printing in a shorter time is required 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 marking 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 the letters or patterns can be identified by the 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).

Since ferric hydroxide is yellow, it can be used only in hues such as yellow and orange, but by using basic copper carbonate, basic lead carbonate, etc., it is possible to use blue or green substrates, especially light-colored bases. It has become possible to apply black laser printing to the base of the.

[Problems to be Solved by the Invention]

The present invention, as a result of earnest studies to obtain a resin composition that discolors with carbon dioxide laser light of lower energy, zirconium silicate (I
It has been found that the inclusion of V) enables clear discoloration even with low-energy carbon dioxide laser light, which has a low degree of discoloration in the past, and based on this finding, various studies have been carried out to complete the present invention. .

The object of the present invention is to provide an epoxy resin composition which gives a cured product capable of sharply printing on the resin surface by irradiation with carbon dioxide laser light of low energy without deteriorating electrical properties and other properties. To provide things.

[Means for Solving the Problems]

The present invention relates to an epoxy resin composition suitable for carbon dioxide laser printing, which contains zirconium (IV) silicate in addition to a laser color material.

The coloring material used in the present invention is not particularly limited, but includes ferric hydroxide, copper hydroxide, copper (II) gluconate, copper (II) carbonate, copper (II) oxalate, and acetic acid. Examples thereof include silver, bismuth oxalate, cobalt oxalate, lead hydroxycarbonate, nickel hydroxide, nickel formate, zinc, aluminum, calcium, magnesium and barium borate, and acetylacetone aluminum.

The epoxy resin composition of the present invention contains zirconium silicate (I
The reason for using V) will be described below in the case where ferric hydroxide is used as the coloring material.

Ferric hydroxide is a yellow powder, and when heated,
It changes to iron (II) oxide dehydrated at 300 ° C and turns brown.

Accordingly, when the epoxy resin composition containing ferric hydroxide is irradiated with a laser in a letter or pattern, the resin surface is heated by the thermal energy of the laser, and the ferric hydroxide contained in the resin is A chemical reaction occurs and turns brown. At this time, zirconium silicate (I
When V) is contained, the absorption amount of laser light in the infrared wavelength region is increased, and the amount converted into thermal energy is increased.
That is, even if the energy of the carbon dioxide gas laser light is low, the temperature rise of the irradiated portion is the same as in the conventional case, the same discoloration occurs, and letters or patterns can be clearly printed on the background.

The content of zirconium (IV) silicate is preferably 1% by weight or more, because the effect is small even if the laser is irradiated when the content is less than 1% by weight.

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 ester type epoxy resins, glycidyl amine type epoxy resins, linear aliphatic type epoxy resins, heterocyclic type epoxy resins, halogenated epoxy resins, and the like, but are not limited thereto.

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 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, red, blue, green, black,
A white pigment or the like 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 Ferric hydroxide (average particle size 10 μm) 5 parts by weight Crystalline silica powder 50 parts by weight 2 Methylimidazole 1 part by weight Zirconium (IV) silicate 10 parts by weight Parts The above compositions were blended, blended with a Henschel mixer, melt-kneaded with a cokneader, 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.

Comparative Example 1 In Example 1, the addition amount of zirconium (IV) silicate was changed to 0.5 parts by weight, and the other conditions were the same and the average particle size was 60 to 7
A powder coating of 0 μm 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 zirconium (IV) silicate was not added.

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 4 Joule / cm ² and 6 Joule / cm ² ) was used to irradiate a laser through a predetermined mask for one millionth of a second to mark the surface of the cured product.

In addition, the insulation coating voltage of the above-mentioned cured product is set to JIS K
It was measured by. The results are shown in Table-1.

[Effects of the Invention] When the epoxy resin composition suitable for laser printing of the present invention is used as an insulating coating material, a sharp print is made on the resin surface by laser irradiation without deteriorating the electrical characteristics and other characteristics. A coating can be applied which can be applied. 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.

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Claims (2)

[Claims] 1. An epoxy resin composition comprising an epoxy resin, a curing agent, a filler, etc., characterized by containing a laser colorant such as ferric hydroxide and zirconium (IV) silicate. object. 2. The epoxy resin composition according to claim 1, which contains zirconium (IV) silicate in an amount of 1 part by weight or more based on the composition.