JPH0310884A - Laser marking method and resin composition for laser marking - Google Patents

Abstract

PURPOSE:To easily perform sharp white marking of high recognizability by irradiating the surface of an article composed of a resin composition containing non-white metal titanate and a resin with laser beam to perform marking. CONSTITUTION:As non-white metal titanate, for example, non-white potassium titanate, sodium titanate or barium titanate are designated and, among them, non-white potassium titanate is pref. The content of non-white titanate is pref. set to 0.5-50wt.% from such an aspect that a lowering of physical properties of a molded article or film is reduced. As a resin used in a molding material, a polyolefinic resin, a vinyl chloride type resin, a polystyrenic resin and an acrylic resin are designated and can be used alone or as a mixture of two or more kinds of them. The surface of a part desired to be marked is formed from a resin composition and may be irradiated with laser beam to perform marking. White marking of high recognizability can be performed with good sensitivity only by the irradiation with laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser marking method for performing white marking using laser light, and a resin composition for laser marking suitable for marking by this method.

[Conventional technology]

The laser marking method is a method of marking marks, barcodes, images, etc. on the surfaces of metals, ceramics, polymeric organic materials, etc. using laser light.
Recently, it has been widely used industrially because it is non-contact, has a fast marking speed, and is easy to automate and control the process.

Laser marking involves irradiating a target surface with a laser beam, and causing two changes: (1) changes in the surface condition due to etching of the irradiated area (roughness and dents), and (2) changes due to decolorization and discoloration of the coloring agent in the irradiated area (for example, JP-A-56-1999). Publication No. 144995, JP-A-60-1
55493), etc., for marking.

[Problem to be solved by the invention]

However, the contrast between the laser beam irradiated area and the non-irradiated area is weak in the state change of the surface in (■), and irradiation with high-energy laser light is required to display the mark. The discoloration method has drawbacks such as the color of the substrate being limited by the colorant that can be bleached and changed, the heat resistance being low, and the use of a coloring agent that is easy to bleach and change the color, making unirradiated areas more likely to change color.

[Means to solve the problem]

As a result of intensive research in view of this situation, the present inventors found that
It has been discovered that clear and highly visible white markings can be easily applied to objects made of a resin composition containing a non-white metal titanate and a resin by simply irradiating the surface with laser light. , we have completed the present invention.

That is, the present invention provides a laser marking method characterized in that the surface of an object made of a resin composition containing a non-white titanate metal salt and a resin is marked by irradiating a laser beam, and a non-white titanium The present invention provides a resin composition for laser marking, which is characterized by containing an acid metal salt and a resin.

The laser used in the present invention is not particularly limited, but carbon dioxide laser - carbon oxide laser, semiconductor laser,
Examples include yttrium neodymium glass laser (YAG laser), among which carbon dioxide laser is preferred.

As a carbon dioxide laser (wavelength: 10.6 μm), for example, Transversely Excited Ato
n+ospheric pre-ssure (TEA
) type carbon dioxide laser, scanning type (continuous oscillation or pulse oscillation) carbon dioxide laser, etc.

As an apparatus, for example, a TEA type carbon dioxide laser has an output of 0.5 to 20 joules/pulse, a pulse duration of 0.1 μ to 10 μ seconds, and a device that can irradiate laser light 1 to 200 times/win, a scanning type. (continuous oscillation or pulse oscillation) carbon dioxide laser has an output of 0.5 to 20,000
In the case of W, pulse oscillation, there are devices with a pulse interval of 2 to 10 kHz.

Examples of the non-white metal titanate used in the present invention include non-white potassium titanate, sodium titanate, lithium titanate, cesium titanate, silver titanate, thallium titanate, strontium titanate, and calcium titanate. , bismuth titanate, lanthanum titanate, cadmium titanate, barium titanate, etc. Among them, non-white potassium titanate is preferred.

Among the above-mentioned non-white potassium titanates, potassium titanate with a chemical composition of 20 ・nTiox (1≦x<1.9) is a highly stable black compound, and a clear and highly visible white compound. It is particularly preferred in that marking can be obtained.

The above chemical composition KzO-nTiox (1≦x<1
．． 9) Potassium titanate having different n and X values can be used as a mixture of two or more. Furthermore, the particle shape is not particularly limited. These compounds may contain water of crystallization.

In addition, the chemical composition includes 0.nTi0. The resistance value of potassium titanate decreases as the value of X decreases, so if insulation is required, it is preferable to reduce the content or use potassium titanate having a chemical composition with a large value of X.

The non-white titanate metal salt can also be used after being surface-treated with a fatty acid metal salt, a silicon-based, titanium-based, or aluminum-based coupling agent, or the like.

Examples of the resin composition for laser marking of the present invention include a molding material containing a non-white metal titanate in a resin, and a composition for coating such as a paint. Moreover, as a product made of this resin composition,
Examples include a molded article formed by molding the molding material, a film formed by coating, drying or curing the coating composition, and the like.

The content of non-white metal titanate varies depending on the type and use of the resin composition and is not constant, but it is usually contained in objects made of the resin composition, such as molded products or coatings that are subjected to laser marking. The ratio is in the range of 0.1 to 80% by weight. Among these, the content is preferably in the range of 0.5 to 50% by weight because clear and highly visible white markings are obtained and the physical properties of molded products, coatings, etc. are less likely to deteriorate.

The resin used for the molding material is not particularly limited, but may include extrusion molding, transfer molding, injection molding,
Thermoplastic resins that can be blow molded, cast molded, press molded, tape molded, etc., such as polyolefin resins, vinyl chloride resins, polystyrene resins, acrylic resins,
Polyvinyl alcohol resin, polyester resin, polycarbonate resin, polyacetal resin, polyphenylene sulfide resin, polyether resin, polyamide resin, polyimide resin, fluorine resin, etc.; thermosetting resin, such as epoxy resin, Phenolic resins, amino resins, polyester resins, polyether resins, acrylic resins, diallyl phthalate resins, urethane resins, aniline resins, furan resins, polyimide resins, silicone resins, fluorine resins, etc. mentioned,
These can be used alone or in combination of two or more.

In addition, the resin used in the coating composition is not particularly limited in its type, but includes brush coating, spray coating, dip coating, gravure coating, doctor coating,
Resins for room-temperature-drying/curable paints, resins for moisture-curable paints, resins for thermosetting paints that can be used for roll coating, electrostatic coating, powder coating, transfer, printing, etc., such as oil varnish, boiled oil, shellac, Cellulose resin, phenolic resin, alkyd resin, amino resin, xylene resin, toluene resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polystyrene resin, vinyl butyral resin, acrylic resin, diallyl Phthalate resin, epoxy resin, urethane resin, polyester resin, polyether resin, aniline resin, furan resin, polyimide resin, silicone resin, fluorine resin, etc.; light or electron beam curing resin, For example, polyvinyl cinnamate resin, polyvinyl benzalacetophenone resin, polyvinyl styryl pyridine resin, polyvinyl alcohol resin, unsaturated polyester resin, acrylated oil, acrylated alkyd resin, acrylated polyester resin. , acrylated polyether resin, acrylated epoxy resin, acrylated polyurethane resin,
Examples include macromonomers, oligomers, and monomers of acrylic resins, acrylated spiran resins, acrylated silicone resins, acrylated fluorine resins, polythiol resins, and cationic polymerizable epoxy resins, which may be used alone or in combination. A mixture of the above can be used.

Incidentally, additives or solvents can be added to the resin used in the molding material and the coating composition, if necessary. Additives include curing agents suitable for the resin used (amine curing agents, acid anhydride curing agents, peroxide curing agents, etc.), drying agents (cobalt naphthenate, calcium naphthenate, etc.), crosslinking agents, and photoinitiation. agents (acetophenone series, benzophenone series, Michler's ketone series, benzyl series,
benzoin series, thioxanthone series, etc.), photosensitizers (butylamine series, triethylamine, diethylaminoethyl methacrylate, etc.), polymerization inhibitors (hydroquinone,
benzoquinone, sodium carbamate compounds, etc.),
Dispersants (metallic soaps, surfactants, etc.), fluidity modifiers (metallic soaps, bentonite, polymerized oil, sodium alginate, casein, Aerosil, organic/inorganic fine particles, etc.), anti-settling agents (lecithin, etc.), Flame retardants (antimony trioxide, phosphoric acid esters, chlorine/bromine flame retardants, etc.), lubricants/I-type agents (paraffin wax, polyethylene wax, montan wax, fatty acids, fatty acid amides, fatty acid esters, fatty alcohols, fatty acids, etc.) (partial esters of alcohols, surfactants, silicon compounds, fluorine compounds, etc.), plasticity (phthalic acid derivatives, adipic acid derivatives, cepatic acid derivatives, trimellitic acid derivatives, epoxy derivatives, fatty acid derivatives, organic phosphoric acid derivatives, etc.) , stabilizers (metallic soaps, organotin compounds, phosphite compounds, etc.), antioxidants (naphthylamine, diphenylamine, quinoline, phenol, phosphite compounds, etc.), ultraviolet absorbers (salicylic acid derivatives, (benzophenone, benzotriazole, hindered amine compounds, etc.)
, reinforcing agents (glass fibers, carbon fibers, ceramic fibers, whiskers, etc.), colorants (inorganic pigments, organic pigments, dyes, etc.), and other additives used in ordinary molding materials and paints. The appropriate amount can be added.

In order to obtain a resin composition containing a non-white metal titanate and a resin, as well as additives, solvents, etc. as necessary, it is sufficient to uniformly mix these by any method, and the method is not particularly limited. .

Laser marking methods include, for example, scanning the surface of the article with a laser beam of an appropriate size spot, or using a TEA-type carbon dioxide laser keyhole with a rectangular laser beam as a mask to cut out the desired shape. , a method of irradiating the surface of an article, and the like.

Examples of marking in the laser marking method of the present invention include capacitors, chip resistors, and inductors.
■Electronic parts such as C; electrical parts such as connector cases and printed circuit boards; products that are normally marked, such as electric wires, key tops, sheets, mechanical parts, housings for electrical products, coupons, cards, etc.; very small, transcription Items that cannot be marked such as items such as items that cannot be marked; Items that are extremely small and require highly accurate marking, such as barcodes.

In order to carry out the laser marking method of the present invention, a resin composition containing a non-white metal titanate and a resin as all or part of the organic material part of the object is used, and the surface of the object is coated with the resin composition. The surface of the part desired to be marked can be coated, by printing, coating or multi-layer molding on a part of the surface of the object with the resin composition, or by forming the resin composition into a tape and pasting it on the surface of the object. It is sufficient to form the resin composition and mark it by irradiating it with laser light, and it is possible to make white markings with high sensitivity and high visibility just by irradiating this laser light.

〔Example〕

The present invention will be explained in more detail by showing Examples and Comparative Examples below. Note that all parts in the examples are parts by weight.

Example 1 Curing accelerator (benzyldimethylamine) 2 parts KKO-
nTiox' (n = 6, x#1.4) 4
Part Silica 10 parts The epoxy resin composition of the above formulation was mixed uniformly with three rolls to obtain a molding material, which was cast between two glass plates to a thickness of 51W, and then heated at 80°C for 5 hours and 160°C. It was cured for 5 hours at 'C' to obtain a black test piece. Next, this test piece was irradiated with laser light for about 3 microseconds through a mask using a pulsed carbon dioxide laser device. The laser irradiation energy at that time was 9 Joule/d. Particularly clear white markings with high visibility were obtained on the surface of the test piece.

Example 2 Photoinitiator (α-hydroxyisobutyl 5-part phenone) KzO·nTiOx (n = 6, x#1.4)
30 parts of the above composition were uniformly mixed in a lab mixer to obtain a coating composition, which was coated on a glass plate to a thickness of 70 μm using a bar coater, and then cured by irradiating ultraviolet light with a high-pressure mercury lamp. , a black test piece was obtained. Next, the laser irradiation energy was set to 7 joules/d.
When carbon dioxide laser light was irradiated in the same manner as in Example 1 except for changing to , clear white markings were obtained.

Example 3 Photoinitiator (α-hydroxyisobutyl 5 parts phenone) K2O-nTiox (n = 6, x' = 1.4)
A black test piece was prepared using 100 parts of the above composition in the same manner as in Example 2, and when irradiated with a 7 joule/c++1 carbon dioxide laser beam, a particularly clear and highly visible white marking was obtained. Ta.

In Example 4, O・nTiOx (n = 6, x#1.1)
When a black test piece was prepared using 40 parts of the above composition in the same manner as in Example 2 and irradiated with 7 Joule/ctA laser light, particularly clear and highly visible white markings were obtained.

Example 5 PEG600 diacrylate 95 parts [NK ester A-600 manufactured by Shin Nakamura Chemical Co., Ltd.] K, O-n
Tiox (n=6, x#1.7) 40 parts A black test piece was prepared using the above composition in the same manner as in Example 2, and exposed to 7 joules/cfli laser light.

When irradiated with , particularly clear and highly visible white markings were obtained.

In Example 6, O・nTiOx (n = 6, x#1.4)
40 parts Dispersant (zinc stearate) 2 parts The composition of the above formulation was sufficiently kneaded at 140°C using a Toyo Seiki ■ Uboplasto Mill to obtain a molding material, which was then molded into a llIn thick sheet using a hot press machine. Then, it was cooled to obtain a black test piece. Then, when 7 joule/cd laser light was irradiated in the same manner as in Example 1, particularly clear and highly visible white markings were obtained.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1, except that carbon black was blended instead of K, O・nTiox (n-6, x'i1.4), and the surface of the test piece was coated with the same method. Although laser light of the same intensity was irradiated, no white color developed and no marking was obtained.

Comparative Example 2: 20-nTiox (n = 6, x: 1.4
) instead of black organic alloy dye (Ciba Geigy 0
RASOL BLA-CK l? A test piece was prepared in the same manner as in Example 2 except that L) was added, and the surface of the test piece was irradiated with a laser beam of the same intensity in the same manner, but no white color developed and no marking was obtained. Ta.

Comparative Example 3: 20-nTiox (n = 6, x!:il,
A test piece was prepared in the same manner as in Example 2 except that carbon black was added instead of 4), and the surface of the test piece was irradiated with laser light of the same intensity in the same manner, but no white color developed. No markings were obtained.

In Comparative Example 4, 0-nTiox (n=6, x #1.4)
A test piece was prepared in the same manner as in Example 6 except that triiron tetroxide, an inorganic black pigment, was blended instead of . No color developed and no markings were obtained.

The laser irradiation results of Examples 1 to 6 and Comparative Examples 1 to 4 are summarized in Table-1.

Table-1 [×: No color development.

C Effects of the Invention] When the surface of an article made of the resin composition for laser marking of the present invention is irradiated with laser light, there is an effect that a white mark with high sensitivity and high visibility can be displayed easily.

Claims (1)

[Scope of Claims] 1. A laser marking method characterized by marking the surface of an object made of a resin composition containing a non-white metal titanate and a resin by irradiating laser light. 2. The method of claim 1, wherein the non-white metal titanate is non-white potassium titanate. 3. The method according to claim 1, wherein the resin composition is a coating composition containing non-white potassium titanate. 4. The method according to claim 1, wherein the resin composition is a molding material containing non-white potassium titanate. 5. A resin composition for laser marking, comprising a non-white metal titanate salt and a resin. 6. The resin composition according to claim 5, wherein the non-white metal titanate is non-white potassium titanate. 7. The resin composition according to claim 5, which is a coating composition containing non-white potassium titanate. 8. The resin composition according to claim 5, which is a molding material containing non-white potassium titanate.