JP5020567B2 - Thermoplastic resin composition for laser marking, thermoplastic resin molded article, and laser marking method - Google Patents

Description

  The present invention relates to a thermoplastic resin composition and a thermoplastic resin molded article containing a mineral filler made of basalt and excellent in laser marking properties, and a laser marking method. Specifically, a thermoplastic resin composition for laser marking, which is excellent in both laser marking properties and mechanical strength, and can be expected to be applied to a wide range of applications, a thermoplastic resin molded body formed by molding the same, and a laser marking method About.

  Reinforced thermoplastic tree compositions containing fillers are widely used in various applications such as electrical and electronic equipment, automobiles, machinery, and parts for daily use. Glass fiber, talc, mica, kaolin, calcium carbonate, wollastonite and the like are most commonly used as the filler reinforcing agent to be blended, and the type and amount thereof are appropriately selected according to the required characteristics.

  On the other hand, in the case of electrical / electronic parts such as breakers and connectors, the product may be marked for the purpose of product identification and design improvement. Examples of this method include screen printing, an ink writing method, and ink spraying by an ink jet method. However, in these methods, there has been a problem of reduction in productivity and economy due to an increase in the manufacturing process of products.

  On the other hand, as a method of marking with good reproducibility and at high speed, a method of marking characters, symbols, etc. (laser marking) using an energy beam such as laser light has been proposed and has recently attracted attention. ing.

  However, the laser marking method is not applicable to all resins, and clear laser marking cannot be performed with a filler-reinforced thermoplastic resin composition such as a simple glass fiber. Therefore, improvement of the laser marking property of the resin composition by blending various substances has been actively studied, and several laser marking property improving resin compositions have been proposed so far.

  Specifically, a resin molded body made of a thermoplastic resin composition containing 0.01 to 1.0% by weight of carbon black has been proposed (see, for example, Patent Document 1).

  In addition, a resin molded article comprising a resin composition having a limiting oxygen index of 22% or more measured by a test method defined in ASTM D2863, which is formed by blending a flame retardant with polyalkylene terephthalate, and coated with the resin composition There has been proposed a laser marking method characterized in that marking is performed by irradiating the surface of a molded body with laser light (see, for example, Patent Document 2).

  On the other hand, as a technique aimed at improving the mechanical strength of the resin composition, several resin compositions in which a filler made of basalt is blended with a thermoplastic resin have been proposed. Specifically, for example, the surface of a core material composed of 100 parts by weight of acrylic-modified polystyrene and 5 to 100 parts by weight of basalt fiber is coated with a skin layer made of acrylonitrile- (ethylene-propylene-diene) -styrene copolymer. A resin molded body (rain gutter) characterized by the above has been proposed (see, for example, Patent Document 3).

  For the purpose of obtaining a thermoplastic resin composition having a high far-infrared radiation effect, a thermoplastic resin composition containing alkali olivine basalt has been proposed (see, for example, Patent Document 4).

  Furthermore, as a synthetic resin molding material for producing a molded article with a decorative pattern, reminiscent of marble pattern, frost pattern, fiber, etc., thermoplastic resin, reinforcing substance such as titanium dioxide and / or filler, and A resin composition having a decorative pattern containing dark mineral fibers (basalt fibers) having a specific shape has been proposed (see, for example, Patent Document 5).

JP-A-5-92657 Japanese Patent Laid-Open No. 5-96386 JP 2002-266480 A JP 2004-217741 A Japanese Patent Laid-Open No. 7-165984

  However, although the method described in Patent Document 1 has a certain degree of improvement effect in laser marking properties, the contrast in laser marking properties is insufficient. In addition, the blending of carbon black has a problem of reducing impact resistance.

  In addition, the method described in Patent Document 2 requires the addition of a flame retardant in order to achieve the critical oxygen index. Generally, the addition of a flame retardant reduces mechanical properties, thermal stability, etc. And there existed a problem that characteristics other than laser marking property fell. Further, in Patent Documents 3, 4, and 5, there has been no description or suggestion on improvement of laser marking properties.

  And when the present inventors examined the technique of patent document 2, it used the polyamide 6 as main component resin, and the nitrogen-type flame retardant which is the flame retardant most commonly used for the polyamide 6 to this As a result of confirming the laser marking property, an experimental result was obtained that printing could not be performed at all. That is, in the technique in the document, it has been found that the laser marking property may not be improved even if the critical oxygen index is increased to the range of the document except for a combination of a specific resin and a flame retardant.

  In view of the situation as described above, the inventors of the present invention have excellent mechanical strength such as rigidity and impact resistance without adding a reinforcing agent such as glass fiber, and heat that becomes a resin molded body excellent in laser marking properties. The plastic resin composition was studied earnestly. As a result, it has been found that the laser marking property on the surface of a thermoplastic resin molded article formed by molding a thermoplastic resin composition in which a specific amount of a filler composed of basalt is blended with a thermoplastic resin is remarkably improved. . The present inventors have also found that the effect of the laser marking becomes remarkable when the laser marking is lighter than the color tone of the surface of the thermoplastic resin molded body in the unirradiated portion of the laser.

  That is, the gist of the present invention is (A) a thermoplastic resin composition for laser marking, containing 0.1 to 300 parts by weight of a filler made of basalt with respect to 100 parts by weight of the thermoplastic resin, and the heat A laser marking method characterized by performing marking by irradiating a laser beam on a surface of a resin molded body made of a plastic resin composition or a molded body coated with the resin composition, and laser marking is performed. The present invention relates to a molded thermoplastic resin product.

  According to the present invention, it is possible to provide a resin composition capable of clear laser marking and a resin molded body formed by molding the resin composition. Further, the resin molded body of the present invention is a molded body having excellent mechanical strength such as rigidity and impact resistance without blending a reinforcing agent such as glass fiber. It can be expected to be widely applied as various parts.

The present invention will be described in detail below.
(A) Thermoplastic resin As the (A) thermoplastic resin used in the present invention, any conventionally known one can be used. A thermoplastic resin is one that can be melted by heating, shaped by cooling after being poured into a mold or die, and taken out from the mold or the like to obtain a molded product.

  Specific examples of the thermoplastic resin (A) used in the present invention include, for example, polyamide resin; polyester resin such as polybutylene terephthalate and polyethylene terephthalate; polycarbonate resin; polyacetal resin; polyphenylene ether resin; polyethylene resin, polypropylene resin, polybutadiene Resin, polyolefin resin such as polymethylpentene resin; polystyrene resin; vinyl resin such as polyvinyl chloride and polyvinyl acetate; polyacrylonitrile, acrylonitrile-styrene copolymer resin (AS resin), acrylonitrile-butadiene-styrene copolymer Examples include resins (ABS resins), polyphenylene sulfide, liquid crystal polymers, and the like. These may be used as themselves (homopolymers) or as copolymers and alloys thereof.

  Among these, polyamide resin and polyester resin are excellent in the balance of various properties such as laser marking property, heat resistance, rigidity, insulation, strength, etc., and being easily flame retardant. A polyamide resin is particularly preferable.

  Examples of the polyamide resin used in the present invention include polycondensation of polymerizable ω-amino acids or lactams thereof, preferably lactams having 3 or more membered rings, or polycondensation of dibasic acids and diamines. The polyamide resin obtained by doing is mentioned.

  Examples of the ω-amino acids or lactams include ε-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Examples of the lactams include ε-caprolactam, enantolactam, capryl lactam, lauryl lactam, α-pyrrolidone, α-piperidone and the like.

  Specific examples of dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, hexadecenedioic acid, eicosandioic acid, eicosadiic acid. Examples include endioic acid, diglycolic acid, 2,2,4-trimethyladipic acid, xylylene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid.

  Examples of diamines include hexamethylene diamine, tetramethylene diamine, nonamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4 (or 2,4,4) -trimethylhexamethylene diamine, bis- (4 4'-aminocyclohexyl) methane, metaxylylenediamine and the like.

  The polyamide resin used in the present invention is preferably a polyamide 6 resin (PA6) mainly composed of ε-caprolactam or ε-aminocaproic acid, and a polyamide 66 resin mainly composed of an equimolar salt of hexamethylenediamine and adipic acid ( PA66), 6/66 copolymerized polyamides mainly composed of an equimolar salt of hexamethylenediamine and adipic acid and ε-caprolactam or ε-aminocaproic acid. These polyamide resins may be used alone or in combination of two or more at any ratio. Among them, PA6 and PA66 are preferable as the polyamide resin.

  The polyamide resin used in the present invention has a viscosity number of 70 to 200 measured at a temperature of 23 ° C. and 96 wt% concentrated sulfuric acid at a polyamide resin concentration of 1 wt% in accordance with ISO 307 (JIS K6933). preferable. When this viscosity number is less than 70, rigidity, dimensional stability, impact resistance, and appearance may be deteriorated. On the other hand, when it exceeds 200, moldability is deteriorated, resulting in poor appearance of the resulting resin molding. There is a case.

  Examples of the polyester resin used in the present invention include a polyester resin composed of dicarboxylic acid or a derivative thereof and diols. The dicarboxylic acid or derivative thereof is usually terephthalic acid or a lower alkyl ester thereof, but may contain other acid components or esters thereof.

  Specifically, for example, phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 4,4′-benzophenone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, Fatty compounds such as aromatic dicarboxylic acids such as 4,4′-diphenylsulfone dicarboxylic acid and 2,6-naphthalenedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid Examples thereof include aliphatic dicarboxylic acids such as cyclic dicarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid, and esters such as lower alkyl and glycol. These may be used alone or in combination of two or more at any ratio.

  The diols are usually mainly ethylene glycol and 1,4-butanediol, but may contain other diol components. Specifically, for example, ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, polypropylene glycol, polytetramethylene glycol, dibutylene glycol, 1,5-pentanediol, neopentyl glycol 1,6-hexanediol, 1,8-octanediol and other aliphatic diols, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, etc. And aromatic diols such as xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) sulfone. These may be used alone or in combination of two or more at any ratio.

  Furthermore, other polyfunctional components such as acid components may be copolymerized. Specifically, for example, hydroxycarboxylic acids such as lactic acid, glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, p-β-hydroxyethoxybenzoic acid, alkoxycarboxylic acids Monofunctional components such as stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, Trifunctional or higher polyfunctional components such as trimethylolpropane, glycerol, pentaerythritol and the like can be mentioned.

  As the polyester resin used in the present invention, an aromatic polyester resin is particularly preferable, and a polybutylene terephthalate (PBT) resin having moderate mechanical strength is particularly preferable. As a polybutylene terephthalate (PBT) resin used for this invention, a terephthalic acid occupies 50 mol% or more of all the dicarboxylic acid components, and a 1, 4- butanediol accounts for 50 weight% or more of all the diols. It is preferable that terephthalic acid accounts for 80 mol% or more, particularly 95 mol% or more of the total dicarboxylic acid component.

  It is preferable that 1,4-butanediol accounts for 80 mol% or more, particularly 95 mol% or more of the total diol component. The intrinsic viscosity of the polyester resin is arbitrary, and may be selected and determined as appropriate. However, if the intrinsic viscosity is too small, the mechanical strength is too low, and conversely, if it is too large, molding becomes difficult, so usually 1,1,2,2-tetrachloroethane / phenol = 1/1 (weight ratio) ) Measured at a temperature of 30 ° C. using a mixed solvent of 0.5) to 3). If the average value is within this range, two or more kinds of polyester resins having different intrinsic viscosities may be used in combination.

  The method for producing the polyester resin used in the present invention is arbitrary, and it may be suitably selected from conventionally known arbitrary conditions and produced using the above-described dicarboxylic acid or a derivative thereof and diols.

(B) Filler made of basalt The filler made of (B) basalt used in the present invention is obtained by pulverizing basalt into an indeterminate or plate-like powder, or by melt spinning basalt and cutting it into a fiber. (Hereinafter abbreviated as basalt fiber). In particular, the present invention is characterized in that the basalt fiber is contained in the thermoplastic resin composition, whereby the rigidity, strength and impact resistance can be remarkably improved simultaneously with the laser marking property.

  The basalt used in the present invention is mainly composed of Ca-rich plagioclase and auginite, and other olivine, orthopyroxene, vision pyroxene, horn blend, biotite, magnetite, titanite, silica mineral, alkali feldspar, phosphorus It contains several kinds of minerals such as apatite, zeolite, nepheline, melilite, leucite and the like as main or subcomponent minerals.

  The filler made of (B) basalt used in the present invention is not particularly limited in its raw material and composition, and the color tone depending on the combination and amount of colored minerals contained in the basalt as a raw material is arbitrary. Less is preferable because it does not inhibit the thermal stability of the resin.

  The filler made of (B) basalt used in the present invention may be used by pulverizing basalt into an indeterminate shape or a plate shape. The average particle diameter may be 0.1 to 200 μm in consideration of the mechanical characteristics of the resin composition of the present invention, and it is particularly preferably 0.2 to 100 μm, particularly preferably 0.5 to 50 μm. The average particle diameter can be measured by laser diffraction or the like.

  Moreover, when using a basalt fiber as a filler which consists of (B) basalt used for this invention, a basalt fiber obtained by the conventionally well-known arbitrary methods can be used. Specific examples of the production method include the methods described in JP-T 9-500080, JP-A 2001-508389, etc., and the melt spinning temperature and other conditions are not limited at all. It is not a thing.

The shape and physical properties of the basalt fiber used in the present invention may be appropriately selected and determined in consideration of the desired physical properties of the resin molded product. Specifically, for example, the tensile modulus is usually preferably 8000 kg / mm ² or more. If the tensile elastic strength is excessively small, it is difficult to exhibit a sufficient reinforcing effect.

  Although the average fiber diameter of the basalt fiber used for this invention is arbitrary, when too small, the impact resistance of a resin molding will fall. On the other hand, if it is too large, the effect of improving the rigidity of the resin molded body may be reduced, basalt fibers may float on the surface layer of the resin molded body (flow mark), or the appearance of laser marking may deteriorate. Therefore, the average fiber diameter of the basalt fiber is usually 0.1 to 50 μm, preferably 7 to 25 μm.

  In the thermoplastic resin composition for laser marking of the present invention, if the average fiber length of the basalt fiber dispersed in the resin component is too short, the effect of improving the rigidity of the resin molded product is reduced, and the impact resistance is reduced. May occur. On the other hand, even if it is too long, appearance defects such as flow marks may occur on the surface of the resin molded body. Therefore, normally, the average fiber length of the basalt fiber dispersed in the resin component is 20 to 10000 μm, preferably 100 to 8000 μm, particularly preferably 200 to 3000 μm.

  The shape of the basalt fiber is, for example, by heating the resin composition at 600 ° C. for 3 hours, incinerating the resin, taking out the fiber, and taking out 1000 to 2000 fibers at random using a microscope, and observing the image. Can be measured.

  In addition, the (B) basalt filler used in the present invention is surface-treated with a coupling agent (for example, a silane compound, a titanium compound, a boron compound, etc.) regardless of its shape. From the viewpoint of product appearance, particularly basalt fiber is preferable because the effect becomes remarkable. The preferred coupling agent varies depending on the type of (A) thermoplastic resin used in the present invention. Specific examples of the surface treatment agent include urethane-based, acrylic-based, epoxy-based, nylon-based sizing agents, Si Examples include coupling agents such as coupling agents and titanium coupling agents. Among these, surface treatment with a silane coupling agent is preferable because it can increase mechanical strength.

  For example, when a polyamide resin or a polyester resin is used as the thermoplastic resin (A), aminosilane or epoxysilane is preferable. The fibers are preferably bundled with a sizing agent (for example, polyvinyl acetate, polyester, etc.) because the handling during the production of the composition becomes good.

  In the present invention, the content of the filler consisting of (B) basalt is 0.1 to 300 parts by weight, more preferably 1 to 125 parts by weight, with respect to 100 parts by weight of (A) thermoplastic resin. Is preferred. By setting it within this range, the effect becomes remarkable when the laser marking is lighter than the color tone of the surface of the thermoplastic resin molded body in the laser non-irradiated portion. If the amount is less than 0.1 parts by weight, the laser marking performance becomes insufficient. On the other hand, if the amount is more than 300 parts by weight, the surface property (appearance) of the resin molded product is remarkably deteriorated, and the impact resistance is also significantly reduced.

  The thermoplastic resin composition for laser marking of the present invention may contain conventionally known arbitrary additives and fillers as long as the effects of the present invention are not impaired. Specifically, for example, reinforcing agents such as glass fibers, glass flakes, glass beads, mica, talc, kaolin, wollastonite, potassium titanate whisker, calcium carbonate; olefin-based, acrylic-based, styrene-based elastomers; Heat stabilizers such as hindered phenols, copper halide compounds, phosphite compounds, phosphate compounds and thioether compounds; light stabilizers such as hindered amines; mold release agents such as polyethylene waxes, higher fatty acid esters and higher fatty acid metal salts; Plasticizers such as normal butylene sulfonic acid amides; Colorants such as carbon black, nigrosine and titanium oxide; Halogen flame retardants such as brominated polystyrenes and brominated epoxies; Phosphorus flame retardants such as phosphazenes, phosphinate metal salts and phosphates Flame retardant; Melami cyanurate Nitrogen flame retardants such as melamine polyphosphate; alkali hydrated metal salts such as magnesium hydroxide, aluminum hydroxide and zinc borate; flame retardants and flame retardant aids such as silicon, polytetrafluoroethylene and antimony trioxide Is mentioned.

  In particular, the thermoplastic resin composition for laser marking of the present invention preferably contains antimony trioxide, a halogen flame retardant, carbon black, nigrosine and the like for the purpose of improving laser marking properties.

  The method for producing the resin composition of the present invention is arbitrary, and may be produced by any conventionally known method for producing a resin molded body. Usually, (A) a thermoplastic resin and (B) a basalt filler, and other additives to be added as necessary may be blended in a predetermined amount, and melt-kneaded. The melt kneading method is not particularly limited and may be any conventionally known method.

  Specifically, for example, using a single-screw or twin-screw extruder, a Banbury mixer, or an apparatus similar to this, all materials may be charged all at once from the root of the extruder and melt-kneaded. When (B) basalt fiber is used as a filler composed of basalt, (A) thermoplastic resin and other additives are introduced from the upstream part of the extruder, melt-kneaded, and then basalt fiber is introduced from the middle stream part. Side feed is preferable because it can be easily controlled to a desired fiber length by suppressing breakage of the basalt fiber, and as a result, mechanical properties such as rigidity and strength can be enhanced.

  Further, after pelletizing two or more kinds of compounds having different additives and compositions, a method of pellet blending or a method of separately blending some powder components may be used.

  The thermoplastic resin molded article of the present invention is also characterized in that a clear laser marking is provided on the surface thereof. The thermoplastic resin molded article of the present invention may be obtained by molding the thermoplastic resin composition for laser marking of the present invention by any conventionally known method, and the production method is not particularly limited. Specific examples include an injection molding method, a hollow molding method, an extrusion molding method, a sheet molding method, a rotational molding method, a laminate molding method, and a press molding method. Among these, an injection molding method that is excellent in productivity is preferable.

  Below, the laser marking regarding the thermoplastic resin molding to which the laser marking of this invention was given, and the laser marking method is demonstrated.

  In the present invention, the type of laser light used for marking is not particularly limited. Specific examples include a gas laser, a solid laser, and a liquid laser.

Examples of the gas laser include a CO ₂ laser, a CO laser, an excimer (ArF, KrF, XeCl, and XeF) laser, an Ar laser, a He—Ne laser, an iodine laser, a copper vapor laser, and the like. As solid lasers, YAG (Nd: YAG etc.) laser, YVO 4 laser, ruby laser, GaAs (GaAsP etc.) laser, GaAlAs (GaAlAsSb etc.) laser, InGaAs (InGaAsSb etc.) laser, InP laser InAs type laser, InSb type laser, ZnS type laser, GaN type laser, CdS type laser, CdSe type laser, PbSnTe type laser and the like. Furthermore, examples of the liquid laser include a neodymium oxide liquid laser, a chelate compound liquid laser, and a dye liquid laser.

Among these, a CO ₂ laser, an excimer laser, a YAG laser, a YVO 4 laser, and the like are preferable, and an Nd: YAG laser characterized by an intrinsic wavelength of 1064 nm is particularly preferable. These lasers may be used alone or in combination of two or more.

  In the laser marking method of the present invention, the above-described laser light is irradiated onto the surface of a resin molded body made of the above-described thermoplastic resin composition for laser marking, or the surface of the molded body coated with the resin composition. Just do it. Then, by performing laser marking, the thermoplastic resin molded body to which the laser marking of the present invention is applied is obtained.

  In the present invention, the laser light irradiation conditions are arbitrary, and may be appropriately selected and determined. Irradiation conditions include output, frequency, irradiation time (scanning speed), pulse conditions, distance and angle from the laser light source to the molded product, etc., and these can be selected and determined as appropriate according to the desired laser marking. That's fine. The irradiation method can also be a scan method and / or a mask method, but the scan method is preferable. When forming a marking by irradiating laser beams having different wavelengths, irradiation may be performed one wavelength at a time, or two or more wavelengths may be irradiated simultaneously.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. The raw materials used in Examples and Comparative Examples are shown below.

(A) a thermoplastic resin;
(A-1) PA6 resin Novamid 1010J Viscosity 118 manufactured by Mitsubishi Engineering Plastics

(A-2) PBT resin Novaduran 5010 manufactured by Mitsubishi Engineering Plastics Co., Ltd., intrinsic viscosity 1.1

(B) Filler made of basalt;
(B-1) Basalt fiber Basalt fiber manufactured by Showa Polymer Co., Ltd. Average fiber diameter: 13 μm (chopped strand in which natural basalt is 100% raw material and a silane coupling agent and a sizing agent are added to melt-spun fibers).

The chemical composition of the basalt fiber is as follows. SiO _2: from 47.4 to 49.6 _{wt%, Al} 2 O 3: _14~15.3 wt%, CaO: from 10.8 to 11.9 wt%, MgO: 8.2-9.7 wt%, FeO: 6.3-9.1 _wt%, Na 2 O: 2.3 _wt%, H 2 O +: _1~1.2 wt%)

(C) Other additives;
(C-1) Glass fiber: ECS03-T-289 manufactured by Nippon Electric Glass Co., Ltd., chopped strand having a fiber diameter of 13 μm

[Examples 1-2 and Comparative Examples 1-4]
The above-described raw materials are melt-mixed at a blending ratio shown in Table 1 at a setting temperature of 240 ° C. and a screw rotation speed of 200 rpm using a twin-screw extruder (TEX-30 XCT manufactured by Nippon Steel Works), and a thermoplastic resin composition. Manufactured.

  (A) The thermoplastic resin was introduced from the upstream part of the extruder, and (B) basalt fiber and glass fiber were introduced from the middle part of the extruder by side feed and melt mixed. The obtained composition was vacuum-dried at 120 ° C. for 8 hours, and then, with an injection molding machine (α100iA manufactured by FANUC), cylinder temperature 250 ° C., mold temperature setting 80 ° C., injection / cooling = 20/20 seconds. An ISO test piece was molded under the conditions.

  The bending elastic modulus was measured on the test piece based on ISO-178. Further, a Charpy impact test with a notch was also performed based on ISO-179. The results are shown in Table 1.

[Evaluation of laser marking characteristics]
Using the obtained thermoplastic resin composition, cylinder temperature 250 ° C., mold temperature setting 80 ° C., injection / cooling = 20/20 seconds on an injection molding machine (JSW J75-ED type manufactured by Nippon Steel) Under the conditions, a flat test piece of 100 mm × 100 mm × 3 mm was molded. Laser marking was performed on the surface of the test piece (resin molded body) using the following laser marker.

  The laser marking conditions were a YAG laser (natural wavelength 1064 nm) for the laser beam, Unimark SY made by Ushio Electric Co., Ltd., and a model SL475H / HF made by NEC Corporation for the marker engine. The marking output current values were 10A and 15A. Marking speed was 200 mm / sec. Marking symbols were marked on two plates. One plate was marked so as to fill a square of 20 × 20 mm, and the other plate was programmed with a pattern for marking 10 alphabet letters A to J with a 5 mm square font.

  Subsequently, the visibility (laser marking property) of the laser irradiated portion (printed portion) is visually determined, and at the same time, a color difference meter (Spectral color difference meter SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.) Light source: halogen lamp C light, 2 degrees, Measurement area: 10 mmΦ. A standard white plate was used as a back plate for fixing the test piece.) ΔE between the laser irradiated portion and the non-irradiated portion was measured and used as an index of contrast (ΔE).

  Specifically, the brightness was measured using a colorimeter for each of the plate before marking and the plate coated with a 20 × 20 mm square. The larger the ΔE, the higher the clearness and the better the laser marking property. The results are shown in Table 1.

From Table 1, it can be seen that the laser markings on the resin moldings made of the thermoplastic resin compositions of Examples 1 and 2 are excellent in sharpness and show good marking properties with strong contrast. Moreover, it can be seen that the mechanical properties are also higher than those of Comparative Examples 1 and 2, indicating high rigidity and high impact resistance. This is apparent from the fact that it is at the same level as Comparative Examples 3 and 4 which are glass reinforced products having excellent rigidity and impact resistance. On the other hand, (B) Comparative Examples 1 to 4 which do not contain basalt fiber were all subjected to laser marking treatment, but only slightly changed in color and could not be subjected to laser marking.

Claims (10)

(A) The thermoplastic resin composition for laser marking which contains 0.1-300 weight part of fillers which consist of (B) basalt with respect to 100 weight part of thermoplastic resins. (B) The thermoplastic resin composition for laser marking according to claim 1, wherein the filler composed of basalt is a basalt fiber having an average fiber diameter of 0.1 to 50 μm and an average fiber length of 200 to 5000 μm. (A) The thermoplastic resin for laser marking according to claim 1 or 2, wherein the thermoplastic resin is at least one thermoplastic resin selected from the group consisting of a thermoplastic polyester resin and a thermoplastic polyamide resin. Composition. When laser marking by laser irradiation is performed on a thermoplastic resin molded product obtained by molding a thermoplastic resin composition, the laser marking color tone is lighter than the color tone of the surface of the thermoplastic resin molded product that has not been irradiated with laser. The thermoplastic resin composition for laser marking according to any one of claims 1 to 3, wherein: The thermoplastic resin composition for laser marking according to any one of claims 1 to 4, wherein the thermoplastic resin composition for laser marking does not contain glass fibers. The thermoplastic resin composition for laser marking according to any one of claims 1 to 4, wherein the thermoplastic resin composition for laser marking does not contain a reinforcing agent other than basalt. Marking is performed by irradiating a laser beam on the surface of a resin molded body comprising the thermoplastic resin composition for laser marking according to any one of claims 1 to 6 or a molded body coated with the resin composition. A characteristic laser marking method. A thermoplastic resin molded article formed by molding the thermoplastic resin composition for laser marking according to any one of claims 1 to 6, wherein the laser marking is performed by laser light irradiation. Plastic resin molding. An electrical / electronic component comprising the thermoplastic resin molded article according to claim 8 . A laser marking improver for thermoplastic resin, characterized by containing basalt.