JP3198473B2 - Epoxy resin composition capable of laser beam marking - Google Patents

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 capable of laser beam marking.

[0002]

2. Description of the Related Art Heretofore, in order to display characters and symbols on the surface of an article such as an electronic component, a transfer printing method using a thermosetting or ultraviolet curing ink has been performed. However, this method has problems in that it is difficult to prevent dust from adhering to the surface of the article, to adjust the familiarity of the ink to the surface of the article, and to require a curing step of the ink after printing. Further, as an alternative to the printing process, the surface of the resin in advance blended lead compound, by irradiating a laser beam, a method of changing the surface to a black has been proposed (Japanese Patent Open Rights 1-222
994, Patent Laid-open flat 2-48984). In this case, as the lead compounds, basic phosphites lead and sulfite lead is preferably used. The present inventors have conducted various studies to develop an epoxy resin composition capable of laser beam marking using such a lead compound, but when the composition contains a curing agent having a carboxyl group, a base is used. Insoluble lead phosphite and lead sulphite cause inconveniences such as the viscosity of the composition being significantly increased and the fluidity of the composition being significantly impaired, and the formation of resin coatings and the molding of resin molded articles are difficult. It has been found.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an epoxy resin composition capable of laser beam marking and having good coatability and resin moldability.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, an epoxy resin, Yu
A curing agent having a releasing carboxyl group, laser beam markable epoxy resin composition comprising a non-basic phosphite lead and / or non-basic sulfite lead is provided.

[0005] The non-basic lead phosphite and lead sulfite (hereinafter, also simply referred to as a lead compound) used in the present invention are usually used in the form of fine powder having an average particle size of 20 µm or less, preferably 5 µm or less. As the epoxy resin used in the present invention, conventionally known ones, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A
Various epoxy resins, such as a D-type epoxy resin and a novolak-type epoxy resin, and mixtures thereof are exemplified.

[0006] The curing agent used in the present invention is one containing a free carboxy group. Examples of such compounds include conventionally known compounds such as aromatic carboxylic acids, alicyclic carboxylic acids, aliphatic carboxylic acids, and acid anhydrides containing a free carboxyl group. Further, in the present invention, the above-mentioned carboxyl group-containing curing agent and a curing agent generally used, for example, an amine-based curing agent, an acid anhydride (containing no free carboxyl group), a novolak resin, a phenol compound and the like. It can also be used in combination.

[0007] In the compositions of the present invention, the amount of non-basic phosphite lead and / or non-basic sulfite lead, the total composition 3
% Or more, preferably 5 to 40% by weight. The curing agent is used in a ratio of 0.1 to 1.5 equivalents, preferably 0.5 to 1.5, per epoxy equivalent of the epoxy resin based on the epoxy resin.

The composition of the present invention may further contain, if necessary, auxiliary components such as a curing accelerator, a filler, a coloring agent, a flame retardant, a mold release agent, and a component for improving dispersibility. Mix. In these auxiliary components, when a component containing a carboxyl group is contained, even if a curing agent containing no carboxyl group is used, non-basic lead phosphite and / or lead sulfite is used. Otherwise, the objects of the present invention will not be achieved.

As the curing accelerator, conventional ones, for example, imidazole compounds, diazabicycloundecene and phenol salts thereof, triphenylphosphine, tertiary amines, latent curing accelerators of amine adducts, dicyandiamide and the like are used. . The non-basic lead phosphite and / or lead sulfite used in the present invention is preferably blended with the epoxy resin in advance as a mixture with a heat-fusible substance in order to improve the dispersibility of the epoxy resin. . Such a mixture can be obtained by melt-kneading a lead compound and a heat-fusible substance at a temperature equal to or higher than the melting temperature of the heat-fusible substance, melt-kneading, solidifying by cooling, and pulverizing. The average particle size of the mixture particles is 5 mm
Or less, preferably 1 mm or less.

As the heat-fusible substance, any substance can be used as long as it melts at a temperature not lower than the melting temperature of the epoxy resin to be compounded and is compatible with the epoxy resin. Examples of the heat-fusible substance include an epoxy resin, a higher fatty acid or a salt or ester thereof, a higher alcohol or an ester compound thereof. When the raw material epoxy resin is solid, it is preferably a raw material epoxy resin. The use ratio of the lead compound is from 10 to 80% by weight based on 100 parts by weight of the heat-fusible substance.
%, Preferably 30 to 60%. When the lead compound and the heat-fusible substance are melt-kneaded, a filler having a low specific gravity can be added to promote uniform dispersibility of the lead compound. In this case, as the light specific gravity filler, specific gravity 4 or less,
Preferably, a filler having a specific gravity of 2 to 4, for example, alumina, silica, magnesia, magnesium carbonate, calcium carbonate, mica, clay, sepiolite and the like are included.
The average particle size of these fillers is 0.3 to 20 μm, preferably
It is 0.5 to 10 μm. The filler has a thixotropic property, for example, the average particle diameter is
Ultrafine silica or alumina of 100 nm or less, average particle size of 3
Aluminum hydroxide of less than μm, fibrous magnesium oxysulfate, fibrous silica, fibrous potassium titanate, flaky mica, montmorillonite-organic base double salt called so-called bentonite and the like can be used. Filler having thixotropic imparting property,
Although it can be used alone, it is preferable to use it in combination with a compound having no thixotropic property.

The filler is used in an amount of 0 to 200 parts by weight, preferably 30 to 100 parts by weight, per 100 parts by weight of the heat-fusible substance. Such a filler increases the viscosity of the melt-kneaded product to prevent sedimentation of the lead compound during the melt-kneading of the heat-fusible substance and the lead compound, and finally the well-dispersed lead compound and the heat-fusible To give a fine powder consisting of a mixture with an active substance.

The composition of the present invention may be in the form of a solid or liquid,
Used as molding and coating materials. When used as a molding material, examples of the molding method include a transfer molding method, an injection molding method, a compression molding method, a cast molding method, and a dipping molding method. When used as a coating material, examples of the coating method include a fluid immersion method, an electrostatic spray method, and a brushing method. When the composition of the present invention is used in a liquid state, a mixed liquid composed of an epoxy resin, a lead compound, a filler, and other additional components, and a mixed liquid composed of a curing agent and a curing accelerator are prepared. And used as an epoxy resin composition and as a molding material and a coating material.

A molded article or a painted article obtained from the epoxy resin composition of the present invention can form a black color mark by a laser beam. Specific examples of the articles to be marked include, for example, electronic and electric parts such as capacitors, resistors, diodes, and ICs coated with a surface resin, and various kinds of resin casings for sealing and the like. Further, since the mark formed according to the present invention has a black color tone, the epoxy resin has a color tone other than the black color in advance, for example, colorless to white, light color, light blue, light green, red, yellow, etc. It is good to keep it bright. Thereby, a black mark with good contrast can be obtained. As a laser beam, a near infrared ray having a wavelength of 1 to 100 μm, particularly a wavelength of 5 to 15 μm is used. As such a laser beam marking generator, various known devices such as a carbon dioxide laser beam marking generator and a YAG laser generator are used.

[0014]

According to the present invention, the epoxy resin composition containing the carboxylic acid-based curing agent according to the present invention contains non-basic lead phosphite and / or lead sulfite as a lead compound, so that the epoxy resin composition can be cured by heating and melting. There is no reaction between the agent and the lead compound, and there is no problem of increasing the viscosity or decreasing the fluidity of the melt, and it is advantageously applied as a molding material or a coating material. Further, by irradiating the cured product of the composition of the present invention with a laser beam, the irradiated portion can be changed to a black color tone.

[0015]

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

Example 1 A composition prepared by mixing the components shown in Table 1 with 100 parts by weight of a liquid epoxy resin (Epicoat 828) in the parts by weight shown in Table 1 was used.
Aluminum metal piece (length: 100mm, width: 25mm, thickness: 1.5mm)
Was applied to a thickness of 0.5 mm and heated at 120 ° C. to form a yellow-white cured resin film. Next, the surface of the sample having the cured resin film was irradiated with a laser beam to form a black mark. In this case, the laser beam marking device used was an IEA CO ₂ laser, Unimark 400 4J
(Joule) type (made by Ushio Inc.). The thickness of the mark formed in this case was 0.2 mm. The quality of the mark thus formed on the sample surface and the surface properties of the coating film were visually determined. The results are shown in Table 1. In Table 1, ○ indicates good and x indicates bad. The curing agent “SL-20” shown in Table 1 is a divalent long-chain carboxylic acid.

[0017]

[Table 1]

Example 2 100 parts by weight of a solid epoxy resin (Epicoat 1004) was melted in a kneader heated to 150 ° C.
A part by weight was added, and the mixture was uniformly melt-mixed for 30 minutes, then solidified by cooling and pulverized. To 120 parts by weight of this pulverized product, 0.5 part by weight of triphenylphosphine, 5 parts by weight of a coloring agent, and a polymerization part shown in Table 2 were added with a curing agent and a lubricant shown in Table 2, and were dry-mixed, and the resulting mixture was heated. And after mixing homogeneously in the molten state,
The mixture was rapidly cooled to room temperature and pulverized. The obtained powder was 80% mesh pass 100% and 250 mesh pass approximately 50%. Next, the powder obtained above was applied to an aluminum metal piece heated at 150 ° C. (length: 60 mm, width: 60 mm, thickness: 3.2 mm) to a thickness of about 0.5 mm by a fluid immersion method, Thereafter, the coating was cured in a hot air drying oven at 120 ° C. for 30 minutes to form a white coating film. next,
A black mark was formed on the sample surface having this coating film by a laser beam in the same manner as in Example 1. The quality of this mark and the surface properties of the coating film were visually determined. Table 2 shows the results.

[0019]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 23/00 B41M 5/26 V (56) References JP-A-2-48984 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) C08L 63/00-63/10 C08K 3/30 C08K 3/32 C08G 59/42 B41M 5/26 H01L 23/00

Claims (1)

(57) [Claims] 1. An epoxy resin composition capable of laser beam marking comprising an epoxy resin, a curing agent having a free carboxyl group, and non-basic lead phosphite and / or non-basic lead sulfite.