JP2010138285A - Thermoplastic resin composition, molded article, and two-color molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition from which a molded article having low frictional resistance and hardly generating frictional noise, while maintaining productivity and laser color developing property, is formed. <P>SOLUTION: The thermoplastic resin composition for laser marking contains a thermoplastic resin, 0.1 to 5 parts by mass of a silicone oil-containing inorganic compound based on 100 parts by mass of the thermoplastic resin, and 0.0001 to 5 parts by mass of a laser light absorber based on 100 parts by mass of the thermoplastic resin, wherein the silicone oil-containing inorganic compound contains an inorganic powder and silicone oil, and the content of the silicone oil is 20 to 80 mass% of the whole amount of the silicone oil-containing inorganic compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermoplastic resin composition, a molded body, and a two-color molded body. More specifically, the present invention relates to a thermoplastic resin composition, a molded body, and a two-color molded body capable of forming a molded body (molded article) that maintains productivity and laser colorability, has low frictional resistance, and hardly generates frictional sound.

  2. Description of the Related Art Conventionally, a marking method using ink is known as a method for printing characters, symbols, designs, etc. on an OA device panel such as a keyboard of a personal computer or a facsimile. However, in this method, it is difficult to mark a portion where marking is difficult (for example, a curved surface), and time for drying after printing is required.

  Therefore, recently, a method of marking the surface of a molded product by laser beam irradiation, that is, a molded product formed of a specific thermoplastic resin composition is irradiated with a laser beam, and a part of the molded product surface disappears by evaporation or thermal decomposition. In addition, a method for expressing characters, symbols, color patterns and the like on the surface of a molded article has been reported. This method has the advantage that it can print well even when marking on a difficult part such as a curved surface, and it does not require time to dry the ink compared to printing using ink. There is.

  Because of such advantages, this marking method is used in many molded products such as medical parts and personal computer keyboards. And as said thermoplastic resin composition, what was obtained by knead | mixing additives (laser light absorber), such as carbon black and a low order titanium oxide, to a thermoplastic resin, for example is reported (for example, patent) Reference 1).

JP 2007-238653 A

  The thermoplastic resin composition described in Patent Document 1 can mark black characters, black symbols, black patterns, etc. on the surface of a transparent molded article with good contrast, and the molded article is excellent in transparency. However, when the molded product comes into contact with other members, a frictional sound may occur. For example, when a button used for a game machine or the like is formed of the thermoplastic resin composition, the button and a support frame for supporting the button may come into contact with each other to generate a frictional sound.

  Therefore, in addition to being able to form molded products with low frictional resistance (that is, improved slidability) and less frictional noise, development of a thermoplastic resin composition that maintains productivity and laser color development has been made. It was anxious.

  The present invention has been made to solve the above-described problems of the prior art, and maintains thermoplasticity and laser colorability, has a low frictional resistance, and can form a molded product that hardly generates frictional noise. A resin composition, a molded body, and a two-color molded body are provided.

  The present invention provides the following thermoplastic resin composition, molded article, and two-color molded article.

[1] The thermoplastic resin, 0.1 to 5 parts by mass of the silicone oil-containing inorganic compound with respect to 100 parts by mass of the thermoplastic resin, and 0.0001 to 5 with respect to 100 parts by mass of the thermoplastic resin The silicone oil-containing inorganic compound contains a part by weight of a laser light absorber, and the silicone oil-containing inorganic compound contains inorganic powder and silicone oil. The content of the silicone oil is based on the total amount of the silicone oil-containing inorganic compound. The thermoplastic resin composition for laser marking, which is 20 to 80% by mass.

[2] The inorganic powder is powdered silica, and the silicone oil has a surface tension at 25 ° C. of 0.015 to 0.035 N / m and a kinematic viscosity at 25 ° C. of 1000 to 200,000. The thermoplastic resin composition for laser marking according to the above [1], which is a methyl alkyl silicone oil of mm ² / sec.

[3] The laser light absorbent according to [1] or [2], wherein the laser light absorber is at least one selected from the group consisting of carbon black, titanium black, metal oxide, sulfide, and nitride. Thermoplastic resin composition for laser marking.

[4] The thermoplastic resin composition for laser marking according to any one of [1] to [3], further containing 0.001 to 10 parts by mass of a colorant with respect to 100 parts by mass of the thermoplastic resin. object.

[5] The thermoplastic resin is at least one selected from the group consisting of an olefin resin, a polyamide resin, a thermoplastic urethane resin, a polyacetal resin, an acrylic resin, a polycarbonate resin, a styrene resin, and an ester resin. The thermoplastic resin composition for laser marking according to any one of [1] to [4].

[6] A molded article obtained by injection molding or extrusion molding the thermoplastic resin composition for laser marking according to any one of [1] to [5].

[7] A support formed of the thermoplastic resin composition for laser marking according to any one of [1] to [5], and a cover made of a transparent thermoplastic resin that covers the support. A two-color molded article.

  The thermoplastic resin composition of the present invention has the effects of maintaining productivity and laser colorability, and forming a molded product that has low frictional resistance and hardly generates frictional noise.

  The molded article of the present invention has the effect of maintaining the laser colorability and hardly generating frictional noise.

  The two-color molded article of the present invention has an effect of maintaining laser color development and hardly generating frictional sound.

  Hereinafter, the best mode for carrying out the present invention will be described, but the present invention is not limited to the following embodiment. That is, it is understood that modifications and improvements as appropriate to the following embodiments are also within the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

[1] Thermoplastic resin composition:
One embodiment of the thermoplastic resin composition for laser marking of the present invention (hereinafter sometimes simply referred to as “the thermoplastic resin composition of the present invention”) is a thermoplastic resin, 100 parts by mass of this thermoplastic resin. On the other hand, it contains 0.0001 to 5 parts by mass of a laser light absorber with respect to 0.1 to 5 parts by mass of the silicone oil-containing inorganic compound and 100 parts by mass of the thermoplastic resin. And a silicone oil containing inorganic compound contains inorganic powder and silicone oil, and the content rate of silicone oil is 20-80 mass% with respect to the whole quantity of a silicone oil containing inorganic compound. Furthermore, it is used as a material of a molded article to be laser marked. Such a thermoplastic resin composition can maintain a productivity and a laser coloring property, and can form a molded product having a small frictional resistance and hardly generating a frictional sound.

[1-1] Thermoplastic resin:
As the thermoplastic resin, a conventionally known thermoplastic resin can be appropriately selected and used. Specifically, it may be at least one selected from the group consisting of olefin resins, polyamide resins, thermoplastic urethane resins, polyacetal resins, acrylic resins, polycarbonate resins, styrene resins, and ester resins. Preferably, it is more preferably at least one selected from the group consisting of a polyamide resin, an acrylic resin, a polycarbonate resin, and a styrene resin. By using these resins, there is an advantage that the laser colorability is improved.

  Examples of the olefin resin include polyethylene and polypropylene. Examples of the polyamide resin include polyamide 6, polyamide 66, polyamide 6T, and polyamide 9T. Examples of the thermoplastic urethane resin include a polyether urethane resin and a polyester urethane resin. Examples of the acrylic resin include polymethyl methacrylate (PMMA) and rubber-reinforced acrylic resin. Examples of the styrene resin include polystyrene, methyl methacrylate-styrene copolymer resin, acrylonitrile butadiene styrene copolymer (ABS), and acrylonitrile styrene copolymer. Examples of ester resins include polyethylene terephthalate (specifically, A-PET, PETG), polybutylene terephthalate copolymer polyester resin, polyethylene naphthalate (PEN), polyarylate (PAR), and the like.

  An acrylic resin is preferably used for white color development, and a polycarbonate resin is preferably used for black color development.

[1-2] Silicone oil-containing inorganic compound:
The silicone oil-containing inorganic compound contains inorganic powder and silicone oil, and the content of the silicone oil is 20 to 80% by mass with respect to the total amount of the silicone oil-containing inorganic compound. By containing such a silicone oil-containing inorganic compound, there is an advantage that the frictional resistance can be reduced without reducing the productivity.

  Here, when silicone oil is added to a thermoplastic resin such as pellets, beads, or flakes, the silicone oil remains because the silicone oil is hardly absorbed by the thermoplastic resin. The excess silicone oil enters between the screw and the barrel during extrusion, so that the screw rotates but the thermoplastic resin slips and becomes idle. Therefore, there has been a problem that the feed amount of the thermoplastic resin by the screw is reduced. Since the thermoplastic resin composition of the present invention uses a silicone oil-containing inorganic compound, that is, a silicone oil-containing inorganic compound containing silicone oil, the silicone oil is excessive as described above. It is difficult to cause a problem that the feed amount is reduced, and it is possible to prevent the feed amount from being lowered. Therefore, there is an advantage that productivity does not decrease.

  The silicone oil-containing inorganic compound can be obtained, for example, by using an inorganic powder as a carrier and impregnating a predetermined amount of silicone oil into the inorganic powder. The inorganic powder is not particularly limited as long as it is a powdery inorganic substance, and examples thereof include silica.

  The content of the inorganic powder is preferably 20 to 80% by mass, more preferably 20 to 70% by mass, and 30 to 60% by mass with respect to the total amount of the silicone oil-containing inorganic compound. Is particularly preferred. When the content is less than 20% by mass, it becomes difficult for the inorganic powder to impregnate the silicone oil, and thus the productivity may be reduced. On the other hand, if it exceeds 80% by mass, it is difficult to sufficiently obtain the effect of adding silicone oil, and the properties of the thermoplastic resin are impaired due to an increase in the proportion of inorganic powder (that is, , The advantage obtained by containing the thermoplastic resin may not be obtained).

  Examples of the silicone oil include methyl alkyl silicone oil, fluorine-modified silicone oil, amino-modified silicone oil, polyether-modified silicone oil, phenol-modified silicone oil, methacrylate-modified silicone oil, and methylphenyl silicone oil. Among these, methyl alkyl silicone oil is preferable.

  The silicone oil preferably has a surface tension at 25 ° C. of 0.015 to 0.035 N / m, more preferably 0.018 to 0.032 N / m, and 0.020 to 0.030 N / m. Particularly preferred is m. If the surface tension is less than 0.015 N / m, the compatibility with the thermoplastic resin may be lowered. On the other hand, if it exceeds 0.035 N / m, the viscosity becomes high and it may be difficult to disperse in the thermoplastic resin. Here, “surface tension” in this specification is a value measured using a surface tension measuring device such as “MPTC” manufactured by LAUDA.

The silicone oil preferably has a kinematic viscosity at 25 ° C. of 1000 to 200,000 mm ² / sec, more preferably 3000 to 180,000 mm ² / sec, and 5000 to 150,000 mm ² / sec. It is particularly preferred that If the kinematic viscosity is less than 1000 mm ² / sec, the compatibility with the thermoplastic resin may be lowered. On the other hand, if it exceeds 200,000 mm ² / sec, the viscosity becomes high and it may be difficult to disperse in the thermoplastic resin. Here, in this specification, “kinematic viscosity” is a value measured using a kinematic viscosity measuring device such as “PVS1” manufactured by LAUDA.

  The content rate of a silicone oil is 20-80 mass% with respect to the whole quantity of a silicone oil-containing inorganic compound, it is preferable that it is 30-80 mass%, and it is still more preferable that it is 40-70 mass%. When the content is less than 20% by mass, the effect of reducing frictional resistance is reduced. Further, since the proportion of the inorganic powder is increased, the function of the thermoplastic resin is not sufficiently exhibited (that is, the advantage obtained by containing the thermoplastic resin cannot be obtained). On the other hand, if it exceeds 80% by mass, it becomes difficult for the inorganic powder to be impregnated with the silicone oil, resulting in a decrease in productivity.

  In addition to the inorganic powder and the silicone oil, the silicone oil-containing inorganic compound may contain other components. Examples of other components include colorants, antioxidants, ultraviolet absorbers, lubricants, stabilizers, flame retardants, inorganic fillers, and organic fillers.

  Content of a silicone oil containing inorganic compound is 0.1-5 mass parts with respect to 100 mass parts of thermoplastic resins, It is preferable that it is 0.3-4 mass parts, 0.5-3 mass parts More preferably. If the content is less than 0.1 parts by mass, the amount of silicone oil is too small, and the effect of reducing frictional resistance cannot be sufficiently obtained. On the other hand, if it exceeds 5 parts by mass, the influence of silicone oil on the base color is increased, the contrast between the base color and the laser color development part is decreased, and the laser color development is deteriorated.

  Conventionally, as a method for reducing the frictional resistance of a molded product, silicone oil is kneaded into a thermoplastic resin, but this method involves a large amount of silicone oil to be kneaded (for example, thermoplastic resin). 1 to 3 parts by mass with respect to 100 parts by mass), the productivity of the molded product is not sufficient, and the laser emission is not sufficient. Further, even if silicone oil is kneaded into a powdery thermoplastic resin, the productivity of the molded product is not sufficient, and the laser emission is not sufficient.

[1-3] Laser light absorber:
The laser light absorber is a compound for printing by absorbing the laser light, converting the light into heat energy, and carbonizing the resin surface with the generated heat. The laser light absorber is preferably at least one selected from the group consisting of carbon black, titanium black, metal oxide, sulfide, and nitride. These compounds are advantageous in that good laser colorability can be obtained. Examples of carbon black include acetylene black, channel black, and furnace black. Examples of the metal oxide include ITO (indium tin oxide), ATO (antimony-doped tin oxide), CuO, Fe ₂ O ₃ , SnO _{2 and the} like. Among these, ITO is particularly preferable. Examples of the sulfide include zinc sulfide, iron sulfide, and carbon disulfide. Examples of the nitride include titanium nitride, silicon nitride, and iron nitride.

  Further, as the laser light absorber, a combination of titanium black and a metal-containing compound can be used. Thus, the outstanding black color development can be obtained by mix | blending a metal containing compound further. Examples of the metal contained in the metal-containing compound include bismuth, nickel, zinc, calcium, copper, titanium, silicon, cobalt, and iron.

  Examples of the metal-containing compound include oxides, carbonates, hydroxides, and organic carboxylates of the above metals. Specifically, bismuth oxide, nickel formate, zinc borate, calcium borate, phosphate zinc, calcium silicate, bismuth hydroxide, basic bismuth carbonate, basic bismuth acetate, nickel hydroxide, copper oxalate, Examples thereof include basic copper carbonate, calcium carbonate, copper thiocyanate, copper citrate, iron oxalate, and titanium oxide. In addition, these metal containing compounds can be used individually by 1 type or in combination of 2 or more types.

  Content of a laser beam absorber is 0.0001-5 mass parts with respect to 100 mass parts of thermoplastic resins, It is preferable that it is 0.0005-4 mass parts, It is 0.001-3 mass parts. More preferably it is. When the content is less than 0.0001 part by mass, heat generation due to laser irradiation is small and color developability is poor. On the other hand, if it exceeds 5 parts by mass, too much heat is generated by laser irradiation, so that the colored portion is burnt and the color developability is poor.

  The number average particle diameter of the laser light absorber is preferably 1 to 120 nm, more preferably 3 to 100 nm, and particularly preferably 5 to 80 nm. If the number average particle diameter is less than 1 nm, heat generation due to laser irradiation is small and color developability may be inferior. On the other hand, if it exceeds 120 nm, too much heat is generated by laser irradiation and color development becomes worse, and the influence on the base color may be increased. Here, the “number average particle diameter” in the present specification is a number average particle diameter measured by using a dynamic light scattering method. The number average particle diameter can be measured using, for example, a trade name “SUPERSCAN SS-550” manufactured by Shimadzu Corporation.

[1-4] Colorant:
It is preferable that the thermoplastic resin composition of the present invention further contains 0.001 to 10 parts by mass of a colorant with respect to 100 parts by mass of the thermoplastic resin. The colorant is other than the laser light absorber.

  Examples of the colorant include inorganic pigments, organic pigments, dyes, and the like. Examples of inorganic pigments include white pigments, yellow pigments, red pigments, and blue pigments. Examples of white pigments include titanium oxide, barium sulfate, zinc sulfide, and zinc oxide. Examples of yellow pigments include iron oxide and titanium yellow. Examples of red pigments include iron oxide. Examples of blue pigments include cobalt blue and ultramarine blue. Examples of the organic pigment include monoazo, condensed azo, disazo, heterocyclic ring, quinacridone, perylene, and phthalocyanine. Examples of the dye include monoazo, anthraquinone, disazo, heterocycle, perinone and thioindigo.

  The content of the colorant is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, as described above, with respect to 100 parts by mass of the thermoplastic resin. It is especially preferable that it is 1-3 mass parts. If the content is less than 0.001 part by mass, the coloring power may be weakened because the addition amount is small. On the other hand, if it exceeds 10 parts by mass, the function of the thermoplastic resin may not be sufficiently exhibited (that is, the advantage obtained by containing the thermoplastic resin may not be obtained).

  Furthermore, additives, such as a mold release agent, a stabilizer, antioxidant, a ultraviolet absorber, a reinforcing agent, can be added to the thermoplastic resin composition of this invention as needed.

  The thermoplastic resin composition of the present invention can be obtained, for example, by mixing predetermined amounts of a thermoplastic resin, a silicone oil-containing inorganic compound, a laser light absorber, and a colorant under conventionally known conditions. .

  The thermoplastic resin composition of the present invention is for laser marking. That is, in a molded product formed using the thermoplastic resin composition of the present invention as a raw material, the irradiated portion is marked (printed) when irradiated with a laser beam.

  Conventionally, characters, symbols, designs, etc. printed on game console buttons, medical parts, personal computer keyboards, etc., were printed by using ink, but when printed using ink, curved surfaces It was difficult to mark such parts. In addition, the ink sometimes peeled off over time.

  Therefore, in recent years, marking by laser irradiation (laser marking) has been performed. In this laser marking, a laser light absorbent (for example, carbon black), which is contained in a molded product (thermoplastic resin composition) and has a property of absorbing laser light, generates heat by the laser light. A desired portion of the molded product is colored. Such laser marking has an advantage that even a portion such as a curved surface can be easily printed, and the printed portion does not peel off.

Examples of the laser medium for the laser beam include neodymium-modified yttrium-aluminum-garnet (YAG), yttrium-vanadium tetroxide (YVO ₄ ), He-Ne laser, Ar laser, CO ₂ laser, excimer laser, semiconductor laser, and dye. A laser etc. can be mentioned. Note that the beam diameter of the laser light can be appropriately selected depending on the intended use.

[2] Molded body:
The molded article of the present invention is obtained by injection molding or extrusion molding the thermoplastic resin composition for laser marking of the present invention. Such a molded article maintains laser colorability and has low frictional resistance, that is, it is difficult to generate frictional noise.

  Conventionally known conditions can be appropriately employed as the injection molding conditions. For example, the composition temperature can be 160 to 320 ° C. (preferably 180 to 300 ° C.).

  As the conditions for extrusion molding, conventionally known conditions can be appropriately employed. For example, the composition temperature can be 160 to 340 ° C. (preferably 180 to 320 ° C.).

[3] Two-color molded product:
The two-color molded article of the present invention has a support formed from the thermoplastic resin composition for laser marking of the present invention, and a cover made of a transparent thermoplastic resin that covers the support. is there. Such a two-color molded article maintains laser colorability and has a low frictional resistance, that is, a frictional noise is hardly generated. For example, when a button of a game machine, a medical part, a keyboard of a personal computer, and the like are formed of the two-color molded body of the present invention, there is an advantage that the covering becomes a protective layer and the laser printing portion is hard to disappear.

  FIG. 1 shows a two-color molded body 10 having a support 11 formed of a thermoplastic resin composition for laser marking and a covering 12 made of a transparent thermoplastic resin that covers the support 11. It is an example. FIG. 2 is a cross-sectional view schematically showing a button portion of the game machine 100. The two-color molded body 10 is fitted into the fixed frame 20 and functions as a button.

  The thickness of the support is preferably 0.5 to 5 mm, and more preferably 0.7 to 4 mm.

  Examples of the transparent thermoplastic resin include polymethacrylstyrene resin (MS resin), AS resin, methyl methacrylate resin (PMMA resin), soft methyl methacrylate resin (soft PMMA resin), polycarbonate resin, polyethylene terephthalate resin, poly Examples include cyclohexane 1,4-dimethylphthalate resin, polystyrene resin, transparent ABS resin, polyvinyl chloride resin, polypropylene resin, and polyethylene resin. Among these, methyl methacrylate resin, soft methyl methacrylate resin, polycarbonate resin, and polyethylene terephthalate resin are preferable from the viewpoint of improving surface hardness characteristics, and methyl methacrylate resin and soft methyl methacrylate resin are more preferable. In addition, it is preferable that the thickness of a coating body is 0.5-5 mm, and it is still more preferable that it is 0.7-4 mm.

  The thickness ratio of the covering to the support (covering / support) is preferably from 1/9 to 9/1, and more preferably from 3/7 to 7/3. This thickness composition ratio has the advantage that cracks and breakage are unlikely to occur in the coated body even when contrast needs to be increased, that is, when laser marking is performed a plurality of times.

  In addition, the two-color molded product may contain other additives such as a mold release agent, a stabilizer, an antioxidant, an ultraviolet absorber, and a reinforcing agent as long as the characteristics are not impaired. Can do.

  The total thickness of the two-color molded body is preferably 1.0 to 10 mm, and more preferably 1.5 to 8 mm. If the thickness is less than 1.0 mm, the covering may become too thin and cracks may easily occur. On the other hand, if it exceeds 10 mm, the coating is too thick and the laser colorability may be inferior.

  The two-color molded body can be formed by co-molding the support and the covering by injection molding. As a co-molding method by injection molding, for example, two colors (two types) of resins such as a core back method, a die slide method, and a rotary method are sequentially injected and filled into the mold from separate injection cylinders. A molding method for producing a molded article of a different material or a different color material can be mentioned.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to these Examples and a comparative example. In addition, “surface tension” and “kinematic viscosity” in Examples and Comparative Examples were measured by the following methods.

surface tension:
The surface tension at 25 ° C. was measured using “MPTC” manufactured by LAUDA.

Kinematic viscosity:
The dynamic viscosity at 25 ° C. was measured using “PVS1” manufactured by LAUDA.

Example 1
100 parts of acrylic resin as thermoplastic resin, 0.1 part of carbon black (manufactured by Cabot, product grade “Monarch # 1000”) as laser light absorber, ultramarine as colorant (commercial grade by Daiichi Kasei Co., Ltd.) “D-981”) 1.0 part, a trade name “Torefill F202” (silica / dimethylsilicone oil = 40/60 mass%, dimethylsilicone oil at 25 ° C., manufactured by Toray Dow Corning Co., Ltd. as a silicone oil-containing inorganic compound Surface tension: 0.021 N / m, kinematic viscosity of dimethyl silicone oil at 25 ° C .: 60000 mm ² / sec, 1.0 part) is kneaded and extruded at 230 ° C. Thus, a resin composition pellet (thermoplastic resin composition) was obtained. As the acrylic resin, a product obtained by mixing 52 parts of the trade name “VRL40”, 33 parts of the trade name “VH”, and 15 parts of the trade name “MF” manufactured by Mitsubishi Rayon Co., Ltd. was used.

Extrudability:
About the obtained resin composition pellets, the amount of discharge (kg / hour) is measured under the condition of a screw rotation speed of 100 rpm using an extruder (trade name “DMG 40 mm”) manufactured by Nippon Placon Co., Ltd., and extrusion molding. Sexuality was evaluated. The evaluation criteria are shown below.
◎: Discharge rate 20 kg / hour or more ○: Discharge amount 15 kg / hour or more, less than 20 kg / hour Δ: Discharge amount 10 kg / hour or more, less than 15 kg / hour ×: Discharge amount 10 kg / hour or less

  Next, the pellets obtained were pre-dried at 90 ° C. for 3 hours, and then injection molded under the condition of 230 ° C. under the trade name “NEX-30” manufactured by Nissei Plastic Industry Co., Ltd., an outer diameter of 23 mm and an inner diameter of 20 mm. A slidability measuring ring having a thickness of 20 mm was formed.

Sliding property:
For the molded slidability measuring ring, use a sliding tester (trade name “EFM-III”) manufactured by Orientec Co., Ltd., and measure for 5 minutes under the conditions of a peripheral speed of 100 mm / second and a load of 0.5 kg. The dynamic friction coefficient was calculated. The slidability was evaluated by this dynamic friction coefficient. The evaluation criteria are shown below.
◎: Dynamic friction coefficient less than 0.1 ○: Dynamic friction coefficient 0.1 or more, less than 0.2 Δ: Dynamic friction coefficient 0.2 or more, less than 0.3 ×: Dynamic friction coefficient 0.3 or more

Laser color development:
Using the resin composition pellets, a flat plate (5 cm × 10 cm × 0.3 cm) was prepared with an injection molding machine (trade name “NEX-30”) manufactured by Nissei Plastic Industry. Next, using a Nd / YAG laser (trade name “RSM30D”, manufactured by Roffin Basel), the flat plate was irradiated with laser at a laser irradiation speed of 400 mm / second to develop predetermined characters. Thereafter, the quality of the contrast between the colored portion and the fabric portion of this flat plate was visually observed and judged according to the following criteria.
◎: Color development visibility is very good ○: Color development visibility is good △: Color development visibility is good ×: Color development visibility is inferior

  The resin composition pellets obtained in this example had an extrusion moldability of “◎”, a slidability of “◯”, and a laser coloring property of “◎”.

(Examples 2 and 3)
Resin composition pellets were obtained in the same manner as in Example 1 except that the blending amounts shown in Table 1 were used. The obtained resin composition pellets were evaluated for the above-described extrusion moldability, slidability, and laser color development. The evaluation results are shown in Table 1.

(Comparative Example 1)
Resin composition pellets (thermoplastic resin composition) were obtained in the same manner as in Example 1 except that the silicone oil-containing inorganic compound was not used. The obtained resin composition pellets were evaluated for the above-described extrusion moldability, slidability, and laser color development. The evaluation results are shown in Table 1.

(Comparative Example 2)
Instead of the silicone oil-containing inorganic compound of Example 1 (trade name “Trefil F202” manufactured by Toray Dow Corning), silicone oil (trade name “SH200-100000CS” manufactured by Toray Dow Corning, Inc.) (dimethylsilicone oil, The surface tension at 25 ° C .: 0.021 N / m, the kinematic viscosity at 25 ° C .: 100000 mm ² / sec. Resin composition pellets (thermoplastic resin composition) were obtained. The obtained resin composition pellets were evaluated for the above-described extrusion moldability, slidability, and laser color development. The evaluation results are shown in Table 1.

(Comparative Example 3)
Resin composition pellets were obtained in the same manner as in Example 1 except that the blending amounts shown in Table 1 were used. The obtained resin composition pellets were evaluated for the above-described extrusion moldability, slidability, and laser color development. The evaluation results are shown in Table 1.

  As is clear from Table 1, the thermoplastic resin compositions of Examples 1 to 3 maintain productivity and laser color development and have low frictional resistance as compared with the thermoplastic resin compositions of Comparative Examples 1 to 3. It was confirmed that it was possible to form a molded product that hardly generated frictional noise.

  The thermoplastic resin composition of the present invention is a material for forming a molded product (for example, a button of a game machine, a medical part, a keyboard of a personal computer, etc.) on which characters, symbols, designs, etc. are printed by laser beam irradiation. Is preferred. The molded body and the two-color molded body of the present invention can be used, for example, as buttons for game machines, medical parts, keyboards for personal computers, and the like.

It is a perspective view which shows one Embodiment of the two-color molded object of this invention. It is sectional drawing which shows a part of game machine which fitted the two-color molded object of this invention.

Explanation of symbols

10: Two-color molded body, 11: Support, 12: Cover, 20: Fixed frame, 100: Game machine.

Claims (7)

Thermoplastic resin,
0.1 to 5 parts by mass of a silicone oil-containing inorganic compound with respect to 100 parts by mass of the thermoplastic resin, and
Containing 0.0001 to 5 parts by mass of a laser light absorber with respect to 100 parts by mass of the thermoplastic resin,
The said silicone oil containing inorganic compound contains inorganic powder and silicone oil, The content rate of the said silicone oil is 20-80 mass% with respect to the whole quantity of the said silicone oil containing inorganic compound. Thermoplastic resin composition. The inorganic powder is powdery silica, and the silicone oil has a surface tension at 25 ° C. of 0.015 to 0.035 N / m and a kinematic viscosity at 25 ° C. of 1000 to 200,000 mm ² /. The thermoplastic resin composition for laser marking according to claim 1, which is a methyl alkyl silicone oil which is seconds.   The thermoplasticity for laser marking according to claim 1 or 2, wherein the laser light absorber is at least one selected from the group consisting of carbon black, titanium black, metal oxide, sulfide, and nitride. Resin composition.   The thermoplastic resin composition for laser marking according to any one of claims 1 to 3, further comprising 0.001 to 10 parts by mass of a colorant with respect to 100 parts by mass of the thermoplastic resin.   The thermoplastic resin is at least one selected from the group consisting of olefin resin, polyamide resin, thermoplastic urethane resin, polyacetal resin, acrylic resin, polycarbonate resin, styrene resin, and ester resin. Item 5. The thermoplastic resin composition for laser marking according to any one of Items 1 to 4.   The molded object obtained by carrying out injection molding or extrusion molding of the thermoplastic resin composition for laser markings as described in any one of Claims 1-5.   2 which has the support body formed with the thermoplastic resin composition for laser markings as described in any one of Claims 1-5, and the coating body which consists of a transparent thermoplastic resin which coat | covers the said support body. Color molded body.

Images