Molded article, method for producing a laser-marked molded article and laser marking method

Abstract

The present disclosure relates to the provision of a molded article with clearly printed markings produced by laser marking, a method for producing the molded article, and a laser marking method that enables clearly printed markings. The molded article of the present disclosure is a molded article formed by molding a resin composition comprising a thermoplastic resin (A) and titanium oxide (B) with a mean particle size of 1 µm or less, having an identification section with a color that differs from the color of the surrounding section, wherein the light reflectance at a wavelength of 355 nm is 17% or less when the resin composition is formed into a product with a thickness of 50 µm, and the protrusion height of the identification section is 6.6 µm or less.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a molded article, a method for producing a laser-marked molded article and a laser marking method. BACKGROUND

[0002] Conventionally, methods such as applying printed labels or various printing techniques, e.g. pad printing and screen printing, were used to provide information such as product names, serial numbers and precautions on resin molded articles.

[0003] However, these recording methods are fraught with problems, such as printing errors due to ink dispersion, difficulties printing on uneven surfaces, and problems printing fine characters. Furthermore, the labeling process also has limitations, including the requirement for a smooth surface on the molded item. Therefore, in recent years, laser marking technology (hereinafter referred to as "laser marking") has been increasingly used as a method to solve these problems. Laser marking is an extremely useful process that enables marking with excellent reproducibility and high speed without the drawbacks described above.

[0004] However, laser marking is not necessarily a technique that can be directly applied to all resins, and in general, improvements in laser markability are investigated through modifications of the resin itself or of the various additives.

[0005] PTL 1, for example, proposes an improvement in the marking properties of black carbon black colored polyamide.

[0006] Furthermore, PTL 2 offers a polyamide resin composition with excellent laser marking properties.

[0007] Furthermore, PTL 3 proposes a resin composition consisting mainly of a thermoplastic polyester resin, brominated polystyrene, antimony compounds, titanium dioxide and glass fibers, which is laser-marked with a fiber laser (wavelength: 1064 nm), resulting in a clear color contrast with the surrounding section. CITATION LIST Patent literature PTL 1: WO 2022 / 191310 A1 PTL 2: JP 2009-035656 A PTL 3: JP 2013-151619 A SUMMARY (Technical Problem)

[0008] However, PTL 1's technology is limited to clearly marking black-colored items, as it cannot achieve improved clarity when marking lightly tinted, gray, or colored resins. Furthermore, laser marking is frequently used not only for printing large amounts of text on labels but also for printing complex figures, such as QR codes. ® , which store large amounts of traceability information. PTL 2's technology still has room for improvement regarding the clarity of the printed markings.

[0009] Furthermore, polyamides often contain fillers, commonly referred to as fillers, to provide reinforcement, reduce shrinkage, and impart flame retardancy or other mechanical properties and functionalities. It is well known that fillers in a polyamide tend to be exposed at the surface. When fillers are exposed at the surface, the color changes compared to polyamides without fillers. Consequently, a polyamide containing fillers presents a challenge for further reducing clarity during laser marking.

[0010] Although PTL 3 is a technology that offers high color contrast in printed parts, it contains antimony compounds and brominated polystyrene, which are known to have harmful effects on the environment and human health, raising safety concerns. The use of such substances as additives in resins is prohibited or is to be restricted. Therefore, there is a need to achieve excellent laser marking properties without the use of such substances.

[0011] The present disclosure was made in view of the above circumstances and is directed to provide a molded article with clearly printed markings produced by laser marking, a method for producing such a molded article and a laser marking method capable of providing clearly printed markings. (Solution to the problem)

[0012] The present revelation is as follows in detail.

[0013] [1] Molded articles formed by molding a resin composition containing a thermoplastic resin (A) and titanium oxide (B) with an average particle size of 1 µm or less and free of antimony-based oxides, wherein the molded article comprises: an identification section with a color tone that differs from a color tone of an surrounding section, wherein a light reflectance at a wavelength of 355 nm is 17% or less when the resin composition is formed into a shaped product with a thickness of 50 µm, and a protrusion height of the identification section is 6.6 µm or less.

[0014] [2] Molded articles according to [1], wherein the thermoplastic resin (A) comprises a polyamide-based resin (A1) and / or a polyester-based resin (A2).

[0015] [3] Molded articles according to [2], wherein the polyamide-based resin (A1) is a semi-aromatic polyamide (A1-2) containing an aromatic ring in its backbone or an alloy of the semi-aromatic polyamide (A1-2) and an aliphatic polyamide (A1-1).

[0016] [4] Molded articles according to [3], wherein the semi-aromatic polyamide (A1-2) contains 10 mol% or more isophthalic acid units per 100 mol% of the sum of all constituent dicarboxylic acid units.

[0017] [5] Molded articles according to at least one of [1] to [4], wherein the glass transition temperature of the resin composition is 90°C or higher.

[0018] [6] Molded articles according to at least one of [1] to [5], wherein the crystallization peak temperature of the resin composition is 240°C or less.

[0019] [7] Molded articles according to at least one of [1] to [6], wherein the resin composition further comprises a filler (C).

[0020] [8] Molded articles according to [7], wherein the resin composition contains the filler (C) in an amount of more than 0.0 parts by mass and 150.0 parts by mass or less per 100 parts by mass of the thermoplastic resin (A).

[0021] [9] Molded articles according to [7] or [8], wherein the filler (C) is at least one selected from the group consisting of glass fibers, calcium carbonate, talc, mica, wollastonite and ground fibers.

[0022]

[10] Molded articles according to at least one of [1] to [9], wherein the resin composition further comprises a flame retardant (D).

[0023]

[11] Molded articles according to

[10] , wherein the flame retardant (D) is at least one selected from the group consisting of a phosphinate salt and a diphosphinate salt.

[0024]

[12] Molded articles according to

[11] , wherein the phosphinate salt is a compound of the following formula (I) and the diphosphinate salt is a compound of the following formula (II): in formula (I) are R 11 and R 12 each independently an alkyl group with 1 or more and 6 or fewer carbon atoms or an aryl group with 6 or more and 10 or fewer carbon atoms, M n11+ is an n11-valent metal ion, M is an element of group 2 or group 15 of the periodic table, a transition element, zinc or aluminum, n11 is 2 or 3, and the respective occurrences of R 11 and R 12 They can be the same or different, and in formula (II) R 21 and R 22 each independently an alkyl group with 1 or more and 6 or fewer carbon atoms or an aryl group with 6 or more and 10 or fewer carbon atoms, Y 21 is an alkylene group with 1 or more and 10 or fewer carbon atoms or an arylene group with 6 or more and 10 or fewer carbon atoms, M' x m21+is an m21-valent metal ion, M' is an element of group 2 or group 15 of the periodic table, a transition element, zinc or aluminum, n21 is an integer of 1 or more and 3 or less, if n21 is 2 or 3, the respective occurrences of R can be 21 , R 22 and Y 21 each occurrence of M' can be the same or different, m21 is 2 or 3, x is 1 or 2, if x is 2, the occurrences of M' can each be the same or different, and n21, x and m21 are integers that satisfy the following relation formula: 2 × n21 = m21 × x.

[0025]

[13] Molded article according to at least one of [1] to

[12] , wherein the resin composition comprises a dye (E) and the brightness (L* value) of the molded article is 25 or more.

[0026]

[14] Molded articles according to at least one of [1] to

[13] , wherein the resin composition contains the titanium oxide (B) in an amount of 0.5 parts by mass or more and 10.0 parts by mass or less per 100 parts by mass of the thermoplastic resin (A).

[0027]

[15] Molded articles according to at least one of [1] to

[14] , wherein a ratio of the developed interface areas Sdr of an interface according to ISO 25178 of the identification section is 0.01 or more and 2.0 or less.

[0028]

[16] Molded article according to at least one of [1] to

[15] , wherein the molded article is a housing for a magnetic switch, a housing for a circuit breaker or a molded article for a connector.

[0029]

[17] Method for producing a laser-marked molded article, comprising: Performing laser marking on a molded article formed by molding a resin composition containing a thermoplastic resin (A), wherein the resin composition is a composition with a light reflectance at a wavelength of 355 nm of 17% or less when formed into a shaped product with a thickness of 50 µm.

[0030]

[18] Method for laser marking of a molded article formed by molding a resin composition containing a thermoplastic resin (A), wherein the resin composition is a composition with a light reflectance at a wavelength of 355 nm of 17% or less when formed into a shaped product with a thickness of 50 µm. (Beneficial effect)

[0031] According to the molded article and the manufacturing process of the above aspect, a molded article with clearly printed markings produced by laser marking can be obtained. According to the laser marking process of the present disclosure, a molded article with clearly printed markings can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic diagram showing a method for measuring light absorption capacity; Fig. Figure 2 shows the measurement results of the light reflectance (%) of production examples 12 and 15; and Fig. Figure 3 shows the measurement results of the light transmittance (%) of production examples 12 and 15. DETAILED DESCRIPTION

[0032] One embodiment of the present disclosure (hereinafter referred to simply as "the present embodiment") is described in detail below. It should be noted that the embodiment described below is an illustrative embodiment for the purpose of describing the present disclosure and is not intended to limit the present disclosure to the following subject matter. The present disclosure can be implemented with suitable modifications that do not deviate from the core of the disclosure.

[0033] In this description, the term "polyamide" refers to a polymer with amide groups (-NHCO-) ​​in the main chain. < <formartikel>>

[0034] The molded article of the present embodiment is a molded article formed by molding a resin composition containing a thermoplastic resin (A) and titanium dioxide (B) with an average particle size of 1 µm or less and free of antimony-based oxides.

[0035] The molded article of the present embodiment has an identification section with a different color than the surrounding section. In this description, the term "identification section" refers to a processed section in which a color difference arises between the irradiated and non-irradiated parts due to the color change of the dye upon laser or heat exposure, making it clearly distinguishable.

[0036] In particular, the identification section provided on the molded article of the present embodiment is preferably a printed section produced by laser marking.

[0037] Furthermore, the term “different shade” in this description may refer to a color difference ΔE* of 3 or more (preferably 5 or more, particularly preferably 10 or more) between the ambient section (unprinted section) and the identification section (printed section), as measured by the method described in the examples below.

[0038] The term “environmental section” refers to an unprinted section with a brightness (L* value) of 40 or more, preferably 50 or more, and more preferably 60 or more, as measured by the method described in the examples.

[0039] The resin composition has a light reflectance of preferably 17% or less, more preferably 15% or less, more preferably 13% or less, more preferably 12% or less, and most preferably 11% or less at a wavelength of 355 nm when formed into a product with a thickness of 50 µm. The light reflectance can be greater than 0%, 1% or more, or 2% or more. The lower the light reflectance, the more the laser beam can penetrate the interior of the formed product, thereby increasing the proportion of the dye that changes color due to the laser beam, resulting in excellent clarity of the printed markings.

[0040] Furthermore, the resin composition has a light transmittance of preferably 98% or less, more preferably 95% or less, more preferably 90% or less, further preferably 85% or less, and particularly preferably 80% or less at a wavelength of 355 nm when formed into a product with a thickness of 50 µm. The lower the light absorption, the more the laser beam can penetrate into the interior of the formed product, thereby increasing the proportion of the dye that changes color due to the laser beam, resulting in excellent clarity of the printed markings.

[0041] The light absorption capacity can be calculated using the following formula: Light absorption capacity (%) = 100% − light transmittance (%) − light reflectance (%)

[0042] The test piece for measuring the light reflectance, with a thickness of 50 µm, can be manufactured using the methods described in the following examples. Examples of manufacturing methods include hot pressing and T-die extrusion film formation. If the test piece is manufactured by hot pressing, it is advantageous to adjust the thickness to the specified value using a spacer.

[0043] The light reflectance at a specific wavelength can be measured using a spectrophotometer. Preferably, a spectrophotometer (V670) manufactured by JASCO Corporation is used in combination with an integrating sphere (ILN-725) for the measurement. Since the light transmitted through the test piece is scattered, it is preferred to use an integrating sphere to capture the scattered light for measurement.

[0044] The light absorption capacity at a specific wavelength can be calculated by measuring the transmittance and reflectance at that wavelength with the spectrophotometer described above and subtracting these values ​​from 100%.

[0045] In the molded article of the present embodiment, the ratio of the developed interface area Sdr to the interface area of ​​the identification section defined in ISO 25178 is preferably 0.01 or more and 2.00 or less, more preferably 0.01 or more and 1.50 or less, even more preferably 0.01 or more and 1.00 or less, and particularly preferably 0.01 or more and 0.5 or less.

[0046] If the developed interface ratio Sdr exceeds the aforementioned range, light scattering increases, resulting in unclear color development of the identification section. It is preferable to keep the developed interface ratio Sdr low (e.g., the upper limit described above or less) because this suppresses light scattering.

[0047] The developed interfacial ratio Sdr is one of the parameters that define the surface roughness of an object according to ISO 25178.

[0048] The interface ratio Sdr described above can be measured according to ISO 25178. It can be measured non-contact, e.g., with a laser.

[0049] More precisely, the developed interfacial ratio Sdr can be measured using a laser microscope (measuring unit: VK-X210, controller: VK-X200) from Keyence Corporation. The developed interfacial ratio Sdr according to ISO 25178 can be measured by setting a 20× objective lens, moving the measuring device to the observation surface, and starting the measurement in "expert" mode.

[0050] When three shaped products are obtained under processing conditions of a wavelength of 355 nm, a scan speed of 1700 mm / s, and a laser power of 0.5 W, 0.75 W, or 1.0 W, the developed surface area ratio (Sdr) preferably lies within the aforementioned range for all shaped products. In this description, the developed surface area ratio can also be referred to as surface roughness.

[0051] In the molded article of the present embodiment, the projection height of the identification section is preferably 6.6 µm or less, more preferably 6.0 µm or less. Additionally, the projection height can be 0.001 µm or more, 0.01 µm or more, or 0.05 µm or more.

[0052] Maintaining the protrusion height at or below the aforementioned numerical value results in a thinner surface layer covering the identification section, thus making the color of the identification section clearer. Furthermore, the clarity and durability of printed markings produced by laser marking on the molded part are improved, as fading of the identification section upon scratching is prevented.

[0053] The protrusion height described above is calculated based on the difference between the mean height of the identification section and the mean height of the unprocessed section near the identification section. The protrusion height can be measured using a non-contact method, e.g., with a laser.

[0054] More precisely, it can be measured using a laser microscope (measuring unit: VK-X210, controller: VK-X200) from Keyence Corporation. The protrusion height described above can be measured as the "mean step height" by setting the objective lens to a magnification of 20×, positioning the measuring device so that the edge of the printed markings enters the field of view, adjusting the settings so that both the printed and unprinted sections are within the field of view, and starting the measurement in "expert mode".

[0055] When three shaped products are manufactured under processing conditions of a wavelength of 355 nm, a scan speed of 1700 mm / sec and a laser power of 0.5 W, 0.75 W or 1.0 W, it is advantageous if the above-mentioned protrusion height meets the requirements for all shaped products.

[0056] The color difference ΔE between the ambient area (unprinted area) and the identification area (printed area) can be measured using the method described in the following examples. For instance, if three shaped products are obtained under processing conditions of a wavelength of 355 nm, a scan speed of 1700 mm / s, and a laser power of 0.5 W, 0.75 W, or 1.0 W, preferably all of the shaped products will meet the above requirements.

[0057] Since the molded article of the present embodiment has the configuration described above, excellent clarity of the printed markings can be achieved by laser marking.

[0058] The resin composition from which the molded article of the present embodiment is constructed is described below. <harz-zusammensetzung>

[0059] The resin composition contains a thermoplastic resin (A) and titanium oxide (B).

[0060] The resin composition can consist exclusively of the thermoplastic resin (A) and the titanium oxide (B), or it can contain the thermoplastic resin (A), the titanium oxide (B), and at least one element from the group consisting of a filler (C), a flame retardant (D), and a dye (E). The resin composition is free of antimony-based oxides. [Thermoplastic resin (A)]

[0061] Examples of thermoplastic resin (A) include polyamide-based resins, polyester-based resins, polyacetal-based resins, polycarbonate-based resins, polyacrylic resins, polyphenylene ether-based resins (including modified polyphenylene ethers obtained by mixing or grafting polyphenylene ethers with other resins), polyarylate-based resins, polysulfone-based resins, polyphenylene sulfide-based resins, polyethersulfone-based resins, polyketone-based resins, polyphenylene ether ketone-based resins, polyimide-based resins, polyamide-imide-based resins, polyetherimide-based resins, polyurethane-based resins, polyolefin-based resins (e.g., α-olefin(co)polymers), and various ionomers.

[0062] The thermoplastic resin (A) is preferably a crystalline resin with a melting point in the range of preferably 100°C or higher and 350°C or lower, more preferably in the range of 150°C or higher and 350°C lower, even more preferably in the range of 200°C or higher and 350°C or lower, and particularly preferably in the range of 225°C or higher and 350°C or lower, an amorphous resin with a glass transition temperature in the range of preferably 50°C or higher and 250°C or lower, more preferably in the range of 60°C or higher and 250°C or lower, more preferably in the range of 80°C or higher and 250°C or lower, further preferably in the range of 85°C or higher and 250°C or lower, and particularly preferably in the range of 90°C or higher and 250°C or lower, or a combination thereof.

[0063] Crystalline resins with the aforementioned melting point ranges are preferred because they are less prone to discoloration or decomposition when overheated during laser marking.

[0064] Amorphous resins with the aforementioned glass transition temperatures are preferred because they are less prone to foaming when overheated during laser marking, which reduces the height of the raised area and the surface roughness. This results in a clearer black color of the titanium oxide discoloration layer on the printed section, thus increasing the contrast with the surrounding area. Furthermore, the reduction in surface roughness reduces light scattering at the surface, which also contributes to improved contrast between the printed section and the surrounding area.

[0065] The melting point of crystalline resins, as used here, refers to the peak temperature of the endothermic peak observed by a differential scanning calorimeter (DSC) upon heating from 23°C at a heating rate of 10°C / min. If two or more endothermic peaks are observed, the peak temperature of the highest temperature peak is taken as the melting point. The enthalpy of the endothermic peak observed at this time is preferably 10 J / g or more, and more preferably 20 J / g or more. Furthermore, the sample should preferably be heated once during the measurement to a temperature of 20°C or higher above the melting point to melt the resin, and then cooled to 23°C at a cooling rate of 10°C / min before use.

[0066] Furthermore, the glass transition temperature Tg of amorphous resins used here refers to the peak temperature (maximum point of tanδ, corresponding to E2 / E1) at which the storage modulus (E1) decreases significantly and the loss modulus (E2) reaches its maximum. This is determined by a measurement performed at an applied frequency of 8 Hz using a dynamic mechanical analyzer while the resin is heated from 23°C at a rate of 3°C / min. If two or more loss modulus peaks are observed, the peak temperature of the highest temperature peak is considered the glass transition temperature. For this measurement, the measurement frequency must be at least once every 20 seconds to increase accuracy. Although there are no specific restrictions regarding the manufacturing process of the sample, it is preferable to use a section from a thermoformed molded part to eliminate the effect of mold deformation.From the point of view of thermal conductivity, the dimensions (width and thickness) of the cutout should be as small as possible.

[0067] The thermoplastic resin (A) can be a homopolymer or a copolymer.

[0068] The thermoplastic resin (A) can be one type of resin described above, or two or more types can be used in combination. The thermoplastic resin (A) can also be a resin as described above, modified with at least one compound selected from unsaturated carboxylic acids, their anhydrides, and derivatives.

[0069] From the point of view of heat resistance, malleability, shapeability and mechanical properties, it is preferable that the thermoplastic resin (A) is one or more resins selected from polyolefin-based resins, polyamide-based resins, polyester-based resins, polyacetal-based resins, polyacrylic resins, polyphenylene-based ether resins and polyphenylene sulfide-based resins.

[0070] The thermoplastic resin (A) preferably contains a polyamide-based resin (A1) and / or a polyester-based resin (A2), more preferably only a polyamide-based resin (A1) and / or a polyester-based resin (A2), and most preferably only a polyamide-based resin (A1). This improves the clarity of the printed markings produced by laser marking. The polyamide-based resin (A1) and / or the polyester-based resin (A2) can be used alone or in combination with other thermoplastic resins.

[0071] The proportion of the total mass of a polyamide-based resin (A1) and / or a polyester-based resin (A2) per 100 wt% of the thermoplastic resin (A) is preferably 10 to 100 wt%, more preferably 30 to 100 wt%, more preferably 50 to 100 wt%, and even more preferably 70 to 100 wt%. Increasing the proportion of these resins in the thermoplastic resin (A) improves the whiteness of the unprocessed section, increases the color difference compared to the processed section, and improves the clarity of the printed markings.

[0072] When both a polyamide-based resin (A1) and a polyester-based resin (A2) are included, the mass ratio of the polyester-based resin (A2) to 100% by mass of the total amount of the polyamide-based resin (A1) and the polyester-based resin (A2) is preferably 5 to 50% by mass, and more preferably 5 to 30% by mass. The above range of values ​​increases heat resistance, making discoloration or decomposition less likely if the processed area overheats during laser marking.

[0073] The mass ratio of the thermoplastic resin (A) per 100 mass % of the resin composition is preferably 20 mass % or more, more preferably 30 mass % or more, even more preferably 40 mass % or more and particularly preferably 50 mass % or more. (Polyamide-based resin (A1))

[0074] The polyamide-based resin (A1) is preferably a semi-aromatic polyamide (A1-2) with an aromatic ring in the backbone or an alloy of an aliphatic polyamide (A1-1) and the semi-aromatic polyamide (A1-2). This improves the clarity of the printed markings produced by laser marking. It should be noted that if the polyamide-based resin (A1) is an alloy, the thermoplastic resin (A) may be a ternary or more alloy combined with another thermoplastic resin(s).

[0075] If the polyamide-based resin (A1) is an alloy as described above, the respective contents of the aliphatic polyamide (A1-1) and the semi-aromatic polyamide (A1-2) in the polyamide-based resin (A1) are not particularly limited.

[0076] In particular, the content of semi-aromatic polyamide (A1-2) is preferably 5.0 parts by mass or more and 100.0 parts by mass or less, more preferably 5.0 parts by mass or more and 95.0 parts by mass or less, more preferably 10.0 parts by mass or more and 80.0 parts by mass or less, and more preferably 15.0 parts by mass or more and 70.0 parts by mass or less, per 100.0 parts by mass of the total amount of aliphatic polyamide (A1-1) and semi-aromatic polyamide (A1-2).

[0077] Furthermore, the content of the aliphatic polyamide (A1-1) is preferably more than 0.0 to 95.0 parts by mass or less, more preferably 5.0 parts by mass or more and 95.0 parts by mass or less, more preferably 7.0 parts by mass or more and 80.0 parts by mass or less, and more preferably 9.0 parts by mass or more and 70.0 parts by mass or less, per 100.0 parts by mass of the total amount of the aliphatic polyamide (A1-1) and the semi-aromatic polyamide (A1-2).

[0078] Maintaining the respective levels of aliphatic polyamide (A1-1) and semi-aromatic polyamide (A1-2) within the above-mentioned numerical ranges improves the clarity of the printed markings produced by laser marking.

[0079] The total mass of the aliphatic polyamide (A1-1) and the semi-aromatic polyamide (A1-2) per 100 wt% of the polyamide-based resin (A1) is preferably 80 wt% or more, more preferably 90 wt% or more and more preferably 100 wt%. (1) Aliphatic polyamide (A1-1)

[0080] The constituent units of the aliphatic polyamide (A1-1) preferably satisfy at least one of the following conditions (1) and (2): (1) An aliphatic dicarboxylic acid unit (A1-1a) and an aliphatic diamine unit (A1-1b) are contained; and (2) At least one constituent unit (A1-1c) selected from the group consisting of lactam units and aminocarboxylic acid units is included.

[0081] The constituent units of the aliphatic polyamide (A1-1) may contain one or more constituent units that satisfy at least one of the conditions (1) and (2) mentioned above. In particular, it is preferred that the constituent units of the aliphatic polyamide (A1-1) satisfy condition (1). (1-1) Aliphatic dicarboxylic acid unit (A1-1a)

[0082] Examples of the aliphatic dicarboxylic acid that forms the aliphatic dicarboxylic acid unit (A1-1a) include straight-chain or branched saturated aliphatic dicarboxylic acids with 3 or more and 20 or fewer carbon atoms.

[0083] Examples of straight-chain saturated aliphatic dicarboxylic acids with 3 or more and 20 or fewer carbon atoms include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, cortic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosandioic acid and diglycolic acid.

[0084] Examples of branched saturated aliphatic dicarboxylic acids with 3 or more and 20 or fewer carbon atoms include dimethylmalonic acid, 2,2-dimethyl succinic acid, 2,3-dimethylglutaric acid, 2,2-diethyl succinic acid, 2,3-diethylglutaric acid, 2,2-dimethylglutaric acid, 2-methyladipic acid and trimethyladipic acid.

[0085] One of these aliphatic dicarboxylic acids, which form these aliphatic dicarboxylic acid units (A1-1a), can be used alone, or two or more of these can be used in combination.

[0086] From the point of view of achieving excellent heat resistance, flowability, toughness, low water absorption and stiffness of the resin composition, a straight-chain saturated aliphatic dicarboxylic acid with 6 or more carbon atoms is preferable to the aliphatic dicarboxylic acid that forms the aliphatic dicarboxylic acid unit (A1-1a).

[0087] Specific examples of preferred straight-chain saturated aliphatic dicarboxylic acids with 6 or more carbon atoms include adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid and eicosandioic acid.

[0088] With regard to the heat resistance of the resin composition, adipic acid, sebacic acid or dodecanedioic acid are preferable.

[0089] The aliphatic polyamide (A1-1) may, as required, contain further units derived from trivalent or higher polycarboxylic acids, provided that the function of the molded article of the present embodiment is not impaired. Examples of trivalent or higher polycarboxylic acids include trimellitic acid, trimesic acid, and pyromellitic acid. One of these trivalent or higher carboxylic acids may be used alone, or two or more may be used in combination. (1-2) Aliphatic diamine unit (A1-1b)

[0090] Examples of the aliphatic diamine that forms the aliphatic diamine unit (A1-1b) include straight-chain saturated aliphatic diamines with 2 or more and 20 or fewer carbon atoms, or branched saturated aliphatic diamines with 3 or more and 20 or fewer carbon atoms.

[0091] Examples of straight-chain saturated aliphatic diamines with 2 or more and 20 or fewer carbon atoms include ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine and tridecamethylenediamine.

[0092] Examples of branched saturated aliphatic diamines with 3 or more and 20 or fewer carbon atoms include 2-methylpentamethylenediamine (also known as 2-methyl-1,5-diaminopentane), 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 2-methyl-1,8-octanediamine (also known as 2-methyloctamethylenediamine), and 2,4-dimethyloctamethylenediamine.

[0093] One of these aliphatic diamines, from which these aliphatic diamine units (A1-1b) are built, can be used alone, or two or more of them can be used in combination.

[0094] Among these, the carbon number of the aliphatic diamine forming the aliphatic diamine unit (A1-1b) is preferably 6 or more and 12 or less, and more preferably 6 or more and 10 or less. A carbon number within or above the lower limit described above further increases the heat resistance of the molded article. Conversely, the crystallinity and demolding properties of the molded article are improved when the carbon number is at or below the upper limit described above.

[0095] Specific examples of preferred straight-chain or branched saturated aliphatic diamines with 6 or more and 12 or fewer carbon atoms include hexamethylenediamine, 2-methylpentamethylenediamine and 2-methyl-1,8-octanediamine.

[0096] Among these, hexamethylenediamine or 2-methylpentamethylenediamine is preferable as a straight-chain or branched saturated aliphatic diamine with 6 or more and 12 or fewer carbon atoms. The incorporation of such an aliphatic diamine unit (A1-1b) further improves the heat resistance and stiffness of the molded article.

[0097] Furthermore, the aliphatic polyamide (A1-1) may optionally contain units derived from a trivalent or higher-level aliphatic amine, provided that the properties of the molded article of the present embodiment are not impaired. An example of such a trivalent or higher-level aliphatic amine is bishexamethylenetriamine. (1-3) At least one structural unit (A1-1c) selected from the group consisting of lactam units and aminocarboxylic acid units

[0098] The aliphatic polyamide (A1-1) can contain at least one structural unit (A1-1c) selected from the group consisting of lactam units and aminocarboxylic acid units. The incorporation of such units leads to the production of polyamides with excellent toughness.

[0099] The terms “lactam unit” and “aminocarboxylic acid unit” used here refer to the polymerized (condensed) forms of lactams and aminocarboxylic acids, respectively.

[0100] Examples of lactams that form the lactam units include butyrolactam, pivadolactam, ε-caprolactam, caprylolactam, enantholactam, undecanolactam and laurolactam (dodecanolactam).

[0101] Among the preferred lactams that form the lactam unit are ε-caprolactam and laurolactam, with ε-caprolactam being preferable. The inclusion of such lactams tends to improve the toughness of the molded article.

[0102] Examples of aminocarboxylic acids that form aminocarboxylic acid units include ω-aminocarboxylic acids and α,ω-amino acids formed by ring opening of lactams.

[0103] Furthermore, straight-chain or branched saturated aliphatic carboxylic acids with 4 or more and 14 or fewer carbon atoms, substituted with an amino group in the ω position, are preferred as the aminocarboxylic acids forming the aminocarboxylic acid units. Examples of such aminocarboxylic acids include 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Para-aminomethylbenzoic acid is also an example of an aminocarboxylic acid.

[0104] One type of these lactams and aminocarboxylic acids that form the structural unit (A1-1c) can be used, or two or more of them can be used in combination.

[0105] The weight-average molecular weight can be used as an indicator of the molecular weight of the aliphatic polyamide (A1-1). The weight-average molecular weight of the aliphatic polyamide is preferably 10,000 or more and 50,000 or less, more preferably 17,000 or more and 45,000 or less, even more preferably 20,000 or more and 45,000 or less, still more preferably 25,000 or more and 45,000 or less, particularly preferably 30,000 or more and 45,000 or less, and most preferably 35,000 or more and 40,000 or less.

[0106] If the weight-averaged molecular weight is within the specified range, a molded article with clearer printed markings produced by laser marking can be obtained.

[0107] The weight-average molecular weight of aliphatic polyamide (A1-1) can be measured, for example, by gel permeation chromatography (GPC). (2) Semi-aromatic polyamide (A1-2)

[0108] The semi-aromatic polyamide (A1-2) is a polyamide with an aromatic ring in the main chain and contains diamine units and dicarboxylic acid units.

[0109] The semi-aromatic polyamide (A1-2) preferably contains 10 mol% or more and 95 mol% or less of aromatic components, more preferably 20 mol% or more and 90 mol% or less of aromatic components, and even more preferably 30 mol% or more and 85 mol% or less of aromatic components, based on the total components of the semi-aromatic polyamide (A1-2). As used herein, the term “aromatic components” refers to an aromatic diamine unit and an aromatic dicarboxylic acid unit.

[0110] The semi-aromatic polyamide (A1-2) preferably contains 10 mol% or more of aromatic dicarboxylic acid units (preferably isophthalic acid units), more preferably 30 mol% or more, more preferably 50 mol% or more of aromatic dicarboxylic acid units (preferably isophthalic acid units), more preferably 75 mol% or more of aromatic dicarboxylic acid units (preferably isophthalic acid units) and particularly preferably 100 mol% of aromatic dicarboxylic acid units (preferably isophthalic acid units) per 100 mol% of the sum of all constituent dicarboxylic acid units contained in the semi-aromatic polyamide (A1-2).

[0111] If the content of aromatic dicarboxylic acid units is at or above the lower limit described above, the printed markings produced by laser marking will be clearer.

[0112] The aromatic dicarboxylic acid unit in the semi-aromatic polyamide (A1-2) is not particularly limited, but a terephthalic acid unit or an isophthalic acid unit is preferred, with the isophthalic acid unit being more preferred.

[0113] It should be noted that the ratio of certain monomer units from which the semi-aromatic polyamide (A1-2) is composed can be determined using techniques such as nuclear magnetic resonance spectroscopy ( 1 can be measured using H-NMR.

[0114] In particular, for example, the respective proportions of units derived from aromatic dicarboxylic acids, units derived from dicarboxylic acids other than aromatic dicarboxylic acids, units derived from aromatic diamines, and units derived from diamines other than aromatic diamines that form the semi-aromatic polyamide (A1-2) can be calculated by dissolving the semi-aromatic polyamide (A1-2) in hexafluoroisopropanol at a concentration of approximately 5 wt% by heating. 1 H-NMR analysis is performed using a nuclear magnetic resonance spectrometer (JNM-ECA-500) manufactured by JEOL Ltd. and the integral ratios are calculated. (2-1) Dicarboxylic acid unit (A1-2a)

[0115] The dicarboxylic acid unit (A1-2a) from which the semi-aromatic polyamide (A1-2) is built is not particularly limited, and examples include aromatic dicarboxylic acid units, aliphatic dicarboxylic acid units, and alicyclic dicarboxylic acid units. (2-1-1) Aromatic dicarboxylic acid unit

[0116] Examples of aromatic dicarboxylic acids that form the aromatic dicarboxylic acid unit, and are not isophthalic acid units, include dicarboxylic acids with a phenyl group or an aromatic group, such as a naphthyl group. The aromatic group of the aromatic dicarboxylic acid can be unsubstituted or contain a substituent.

[0117] Examples of substituents include, but are not limited to, alkyl groups with 1 or more and 4 or fewer carbon atoms, aryl groups with 6 or more and 10 or fewer carbon atoms, arylalkyl groups with 7 or more and 10 or fewer carbon atoms, alkylaryl groups with 7 or more and 10 or fewer carbon atoms, halogen groups, silyl groups with 1 or more and 6 or fewer carbon atoms, and sulfonic acid groups and their salts (such as sodium salts).

[0118] Examples of alkyl groups with 1 or more and 4 or fewer carbon atoms include, but are not limited to, the methyl group, the ethyl group, the n-propyl group, the isopropyl group, the n-butyl group, the isobutyl group and the tert-butyl group.

[0119] Examples of aryl groups with 6 or more and 10 or fewer carbon atoms include phenyl groups and naphthyl groups.

[0120] Examples of arylalkyl groups with 7 or more and 10 or fewer carbon atoms include, but are not limited to, the following benzyl groups.

[0121] Examples of alkylaryl groups with 7 or more and 10 or fewer carbon atoms include tolyl groups and xylyl groups.

[0122] Examples of halogen groups include fluorine, chlorine, bromine, and iodine groups.

[0123] Examples of silyl groups with 1 or more and 6 or fewer carbon atoms include trimethylsilyl groups and tert-butyldimethylsilyl groups.

[0124] With the exception of the isophthalic acid units, the aromatic dicarboxylic acids forming the aromatic dicarboxylic acid unit are preferably aromatic dicarboxylic acids with 8 or more and 20 or fewer carbon atoms, which are unsubstituted or substituted with specific substituents.

[0125] Specific examples of such aromatic dicarboxylic acids include terephthalic acid, naphthalenedicarboxylic acid, 2-chlorotephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid and 5-sodium sulfoisophthalic acid.

[0126] To form the aromatic dicarboxylic acid unit, one aromatic dicarboxylic acid alone or two or more aromatic dicarboxylic acids in combination can be used. (2-1-2) Aliphatic dicarboxylic acid unit

[0127] Examples of aliphatic dicarboxylic acids that form the aliphatic dicarboxylic acid unit include straight-chain or branched saturated aliphatic dicarboxylic acids with 3 or more and 20 or fewer carbon atoms.

[0128] Specific examples of straight-chain saturated aliphatic dicarboxylic acids with 3 or more and 20 or fewer carbon atoms include, among others, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, cortic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosandioic acid, and diglycolic acid.

[0129] Specific examples of branched saturated aliphatic dicarboxylic acids with 3 or more and 20 or fewer carbon atoms include, among others, dimethylmalonic acid, 2,2-dimethyl succinic acid, 2,3-dimethylglutaric acid, 2,2-diethyl succinic acid, 2,3-diethylglutaric acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid. (2-1-3) Alicyclic dicarboxylic acid unit

[0130] The alicyclic dicarboxylic acids that form the alicyclic dicarboxylic acid unit (hereinafter sometimes referred to as the "alicyclic dicarboxylic acid unit") include, among others, the following alicyclic dicarboxylic acids with an alicyclic structure having 3 or more and 10 or fewer carbon atoms. Of these, alicyclic dicarboxylic acids with an alicyclic structure having 5 or more and 10 or fewer carbon atoms are preferred.

[0131] Examples of such alicyclic dicarboxylic acids include 1,4-cyclohexane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, and 1,3-cyclopentane dicarboxylic acid. Of these, 1,4-cyclohexane dicarboxylic acid is the preferred alicyclic dicarboxylic acid.

[0132] To form the alicyclic dicarboxylic acid unit, one alicyclic dicarboxylic acid alone or two or more alicyclic dicarboxylic acids in combination can be used.

[0133] The alicyclic group in the alicyclic dicarboxylic acid can be unsubstituted or contain a substituent. Suitable substituents include, for example, alkyl groups with one or more and four or fewer carbon atoms. Examples of alkyl groups with one or more and four or fewer carbon atoms include those found in the aforementioned "aromatic dicarboxylic acid units."

[0134] The dicarboxylic acid unit, which is not an isophthalic acid unit, preferably contains an aromatic dicarboxylic acid unit, and preferably an aromatic dicarboxylic acid with 6 or more and 12 or fewer carbon atoms.

[0135] The use of such dicarboxylic acids results in a resin composition with improved mechanical properties. Furthermore, a molded part can be produced with clearer, laser-marked printed markings.

[0136] In the semi-aromatic polyamide (A1-2), the dicarboxylic acid forming the dicarboxylic acid unit (A1-2a) is not limited to the compounds listed above as dicarboxylic acids, but can be any compound equivalent to the above dicarboxylic acids.

[0137] The term "dicarboxylic acid equivalent compound" used here refers to a compound that may possess a dicarboxylic acid structure similar to the dicarboxylic acid structure derived from the aforementioned dicarboxylic acid. Such compounds include, but are not limited to, anhydrides and halides of dicarboxylic acids.

[0138] Furthermore, the semi-aromatic polyamide (A1-2) can contain additional units derived from trivalent or higher-valent carboxylic acids as required, without impairing the effects of the molded article of the present embodiment.

[0139] Examples of trivalent or higher carboxylic acids include trimellitic acid, trimesic acid, and pyromellitic acid. One of these trivalent or higher carboxylic acids can be used alone, or two or more can be used in combination. (2-2) Diamine unit (A1-2b)

[0140] The diamine unit (A1-2b) forming the semi-aromatic polyamide (A1-2) is not particularly limited, and examples include aromatic diamine units, aliphatic diamine units, and alicyclic diamine units. Among these, the semi-aromatic polyamide (A1-2) preferably contains a diamine unit (A1-2b) having 4 or more and 10 or fewer carbon atoms, and more preferably it contains a diamine unit having 6 or more and 10 or fewer carbon atoms. (2-2-1) Aliphatic diamine unit

[0141] Examples of aliphatic diamines that form the aliphatic diamine unit include straight-chain saturated aliphatic diamines with 4 or more and 20 or fewer carbon atoms.

[0142] Examples of straight-chain saturated aliphatic diamines with 4 or more and 20 or fewer carbon atoms include ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, and tridecamethylenediamine. (2-2-2) Alicyclic diamine units

[0143] Examples of alicyclic diamines that form the alicyclic diamine unit (hereinafter also referred to as "alicyclic diamines") include, but are not limited to, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine and 1,3-cyclopentanediamine. (2-2-3) Aromatic diamine units

[0144] Aromatic diamine units are not limited to the following, as long as they are aromatic diamines containing an aromatic group. Specific examples of aromatic diamines include, for example, m-xylylenediamine.

[0145] A diamine can be used alone, or two or more diamines can be used in combination to form any diamine unit.

[0146] Among these, aliphatic diamine units (A1-2b) are preferred, straight-chain saturated aliphatic diamine units with 4 or more and 10 or fewer carbon atoms are further preferred, straight-chain saturated aliphatic diamine units with 6 or more and 10 or fewer carbon atoms are further preferred, and hexamethylenediamine units are particularly preferred.

[0147] The use of such diamines results in a resin composition with excellent mechanical properties. Furthermore, a molded article can be produced with clearer, laser-marked printed markings.

[0148] The weight-average molecular weight can be used as an indicator of the molecular weight of the semi-aromatic polyamide (A1-2). The weight-average molecular weight of the semi-aromatic polyamide is preferably 10,000 or more and 50,000 or less, more preferably 15,000 or more and 45,000 or less, more preferably 15,000 or more and 40,000 or less, still more preferably 17,000 or more and 35,000 or less, particularly preferably 17,000 or more and 30,000 or less, and most preferably 18,000 or more and 28,000 or less.

[0149] If the weight-averaged molecular weight is within the specified range, a molded article with clearer printed markings produced by laser marking can be obtained.

[0150] The weight-average molecular weight of the semi-aromatic polyamide (A1-2) can be measured, for example, using GPC. (3) End capping devices

[0151] The ends of the polyamide-based resin (A1) can be capped with a known end capping agent.

[0152] Such an end-capping agent can be added as a molecular weight regulator when a polyamide is produced from the dicarboxylic acids and diamines described above or from at least one of the lactams and aminocarboxylic acids described above.

[0153] Examples of end-capping agents include, but are not limited to, monocarboxylic acids, monoamines, acid anhydrides (such as phthalic anhydride), monoisocyanates, monoesters, and monoalcohols. A single end-capping agent or two or more end-capping agents in combination may be used.

[0154] Among these, monocarboxylic acids or monoamines are preferred as end-capping agents. Capping the ends of the polyamide with the end-capping agent results in improved thermal stability of the molded article.

[0155] The monocarboxylic acids that can be used as end-capping agents are not particularly limited, as long as they are reactive with the amino groups that may be present at the ends of the polyamide. Examples of monocarboxylic acids include, among others, aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids.

[0156] Examples of aliphatic monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid and isobutyric acid.

[0157] Examples of alicyclic monocarboxylic acids include cyclohexanecarboxylic acid.

[0158] Examples of aromatic monocarboxylic acids include benzoic acid, toluic acid, α-naphthoic acid, β-naphthoic acid, methylnaphthoic acid, and phenylacetic acid.

[0159] One of these monocarboxylic acids can be used alone, or two or more of them can be used in combination.

[0160] In particular, the ends of the semi-aromatic polyamide (A1-2) are preferably capped with acetic acid with regard to flowability and mechanical strength.

[0161] The monoamines that can be used as end-capping agents are not particularly limited, as long as they are reactive with the carboxyl groups that may be present at the ends of the polyamide. Examples of monoamines include, but are not limited to, aliphatic monoamines, alicyclic monoamines, and aromatic monoamines.

[0162] Examples of aliphatic monoamines include methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine.

[0163] Examples of alicyclic monoamines include cyclohexylamine and dicyclohexylamine.

[0164] Examples of aromatic monoamines include aniline, toluidine, diphenylamine, and naphthylamine.

[0165] One of these monoamines can be used alone, or two or more of them can be combined.

[0166] A resin composition containing a polyamide capped with an end capping agent tends to exhibit better heat resistance, flowability, toughness, low water absorption, and stiffness. (4) Preferred polyamide-based resins (A1)

[0167] Preferred polyamide-based resins (A1) are not particularly limited, but examples include polyamides obtained by polycondensation reactions of lactams, such as polyamide 6, polyamide 11 and polyamide 12; and polyamides obtained as copolymers of diamines and dicarboxylic acids, such as polyamide 66, polyamide 610, polyamide 611, polyamide 612, polyamide 66 / 6I, polyamide 4T, polyamide 6T, polyamide 6I, polyamide 6I / 6T, polyamide 9T, polyamide 10T, polyamide 2M5T, polyamide MXD6, polyamide 6C and polyamide 2M5C.

[0168] Among these, one or more aliphatic polyamides selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 611 and polyamide 612, or one or more semi-aromatic polyamides selected from the group consisting of polyamide 66 / 6I, polyamide 6T, polyamide 6I, polyamide 6I / 6T, polyamide 9T and polyamide MXD6, are preferred. (Method for the production of a polyamide-based resin (A1))

[0169] In the production of the polyamide-based resin (A1) (aliphatic polyamide (A1-1) and semi-aromatic polyamide (A1-2)), it is preferable that the amounts added of the dicarboxylic acid and the diamine are approximately equimolar. Taking into account the escape of the diamine from the reaction system during the polymerization reaction, it is preferred that the molar ratio of the total molar amount of diamine to the total molar amount of dicarboxylic acid is 0.9 or more and 1.2 or less, more preferably 0.95 or more and 1.1 or less, and even more preferably 0.98 or more and 1.05 or less.

[0170] The process for producing the polyamide includes, among other things, a polymerization step according to one of the following methods (1) or (2). (1) The step of polymerizing a combination of the dicarboxylic acid forming the dicarboxylic acid unit and the diamine forming the diamine unit to obtain a polymer. (2) The step of polymerizing one or more selected from the group consisting of a lactam forming the lactam unit and an aminocarboxylic acid forming the aminocarboxylic acid unit to obtain a polymer.

[0171] Furthermore, it is preferred that the process for producing the polyamide includes, after the polymerization step, a boosting step to increase the degree of polymerization of the polyamide. If necessary, a capping step can follow the polymerization step and the boosting step, in which the ends of the resulting polymer are capped with an end capping agent.

[0172] Specific examples of processes for the production of polyamide include various processes, such as those described below under 1) to 4). 1) A process in which an aqueous solution or aqueous suspension of one or more selected from the group consisting of a dicarboxylic acid diamine salt, a mixture of a dicarboxylic acid and a diamine, a lactam and an aminocarboxylic acid is polymerized by heating while maintaining the molten state (hereinafter sometimes referred to as a "thermal melt polymerization process"). 2) A process in which a polyamide obtained by the thermal melt polymerization process is kept in the solid state at a temperature equal to or lower than the melting point in order to increase the degree of polymerization (hereinafter sometimes referred to as the ‘thermal melt polymerization solid-state polymerization process’). 3) A process in which one or more selected from the group consisting of a dicarboxylic acid diamine salt, a mixture of a dicarboxylic acid and a diamine, a lactam and an aminocarboxylic acid are polymerized while maintaining a solid state (hereinafter referred to as the “solid-phase polymerization process”). 4) A process in which a dicarboxylic acid halide component equivalent to a dicarboxylic acid and a diamine component are used for polymerization (hereinafter sometimes referred to as the “solution process”).

[0173] Among these, a manufacturing process involving thermal melt polymerization is preferred as a specific method for producing the polyamide. When the polyamide is produced by the thermal melt polymerization process, it is advantageous to maintain the molten state until polymerization is complete. To maintain the molten state, it is necessary to produce the polyamide composition under polymerization conditions suitable for the specific polyamide composition. Examples of such polymerization conditions include the following: First, heating is continued while the polymerization pressure in the thermal melt polymerization process is increased to 14 kg / cm². 2 or more and 25 kg / cm² 2 or less (overpressure). The pressure in the tank is then regulated over a period of at least 30 minutes until atmospheric pressure is reached (overpressure is 0 kg / cm²). 2 ) reduced.

[0174] The process for producing polyamide is not particularly restricted in the form of polymerization and can be a batch or continuous process. The polymerization apparatus used for producing polyamide is also not particularly limited; any known apparatus can be used. Specific examples of polymerization apparatus include autoclave reactors, tumbler reactors, and extruder reactors (such as kneaders).

[0175] The following describes a specific process for the production of polyamide by a batch-type thermal melt polymerization process, but the process for producing polyamide is not limited to this.

[0176] First, an aqueous solution is prepared containing approximately 40 wt% or more and 60 wt% or less of the raw material components for the polyamide (at least one selected from the group consisting of a combination of dicarboxylic acid and diamine, and optionally lactams and aminocarboxylic acids). The aqueous solution is then concentrated in a concentration tank operated at a temperature of 110°C or higher and 180°C or lower, and a pressure of approximately 0.035 MPa or more and 0.6 MPa or less (gauge pressure), to obtain a concentrated solution of approximately 65 wt% or more and 90 wt% or less.

[0177] The resulting concentrated solution is then transferred to an autoclave and heated further until the pressure in the autoclave reaches approximately 1.2 MPa or more and 2.2 MPa or less (overpressure).

[0178] The pressure in the autoclave is then maintained at approximately 1.2 MPa or more and 2.2 MPa or less (gauge pressure) while at least one of the water and gas components is removed. When the temperature reaches approximately 220°C or more and 260°C or less, the pressure is reduced to atmospheric pressure (gauge pressure is 0 MPa). After the pressure in the autoclave has been reduced to atmospheric pressure, the water produced as a byproduct can be effectively removed by further reducing the pressure in the autoclave, if necessary.

[0179] The autoclave is then pressurized with an inert gas such as nitrogen to extrude the polyamide melt as strands. The extruded strands are cooled and cut to obtain polyamide granules.

[0180] The polyester-based resin (A2) is a polyester obtained by polycondensation of a dicarboxylic acid compound and a dihydroxy compound, by polycondensation of an oxycarboxylic acid compound, by polycondensation of these compounds or the like, and can be either a homopolyester or a copolyester.

[0181] One type of polyester-based resin (A2) can be used alone or as an alloy of several resins.

[0182] Aromatic dicarboxylic acids or their ester-forming derivatives are preferably used as the dicarboxylic acid compound from which the polyester-based resin (A2) is built.

[0183] Examples of aromatic dicarboxylic acids are terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl 2,2'-dicarboxylic acid, biphenyl 3,3'-dicarboxylic acid, biphenyl 4,4'-dicarboxylic acid, diphenyl ether 4,4'-dicarboxylic acid, diphenylmethane 4,4'-dicarboxylic acid, diphenylsulfone 4,4'-dicarboxylic acid, diphenylisopropylidene 4,4'-dicarboxylic acid, 1,2-bis(phenoxy)ethane 4,4'-dicarboxylic acid, anthracene 2,5-dicarboxylic acid, anthracene 2,6-dicarboxylic acid, p-terphenylene 4,4'-dicarboxylic acid and pyridine 2,5-dicarboxylic acid, with terephthalic acid being particularly preferred.

[0184] Two of these aromatic dicarboxylic acids can be used in a mixture. As is well known, these can be used in polycondensation reactions not only in the form of the free acid, but also in the form of ester-forming derivatives such as dimethyl esters.

[0185] In addition, small amounts of aliphatic dicarboxylic acids such as adipic acid, azelaic acid, dodecanedioic acid and sebacic acid or alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid can be used together with these aromatic dicarboxylic acids.

[0186] Examples of the dihydroxy compound from which the polyester-based resin (A2) is constructed include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, hexylene glycol, neopentyl glycol, 2-methylpropane-1,3-diol, diethylene glycol, and triethylene glycol; cyclic diols such as cyclohexane-1,4-dimethanol; and mixtures thereof. Additionally, small amounts of long-chain diols with a molecular weight of 400 to 6,000, such as polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol, can be copolymerized.

[0187] In addition, aromatic diols such as hydroquinone, resorcinol, naphthalene diols, dihydroxydiphenyl ethers and 2,2-bis(4-hydroxyphenyl)propane can also be used.

[0188] In addition to the bifunctional monomers described above, small amounts of trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol and trimethylolpropane can be used to introduce branched structures, and monofunctional compounds such as fatty acids can be used to control molecular weight.

[0189] Typically, the polyester-based resin (A2) is obtained mainly from the polycondensation of dicarboxylic acids and diols, wherein 50 wt% or more, preferably 70 wt% or more, of the total resin originates from such polycondensates. Aromatic carboxylic acids are preferably used as dicarboxylic acids and aliphatic diols are preferably used as diols.

[0190] Among these, polyalkylene terephthalates are particularly preferred, in which 95 mol% or more of the acid component terephthalic acid and 95 wt% or more of the alcohol component is an aliphatic diol. Representative examples include polybutylene terephthalate and polyethylene terephthalate. Those that are nearly homopolyesters are preferred, meaning that 95 wt% or more of the total resin consists of terephthalic acid components and 1,4-butanediol or ethylene glycol components.

[0191] It is particularly preferable that the main component of the polyester-based (A2) resin is polybutylene terephthalate.

[0192] The intrinsic viscosity of the polyester-based resin (A2) is preferably 0.5 to 2 dl / g. From the perspective of formability and mechanical properties, a polyester-based resin with a limiting viscosity in the range of 0.6 to 1.5 dl / g is preferable. If a polyester-based resin with a limiting viscosity of less than 0.5 dl / g is used, the resulting resin composition tends to exhibit low mechanical strength. Conversely, if the limiting viscosity exceeds 2 dl / g, the resin composition may exhibit poor flowability, leading to reduced formability. The limiting viscosity of the thermoplastic polyester resin is measured using a solvent mixture of tetrachloroethane and phenol in a 1:1 ratio (by mass) at 30°C. [Titanium oxide (B)]

[0193] The resin composition contains as essential components the thermoplastic resin (A) described above and titanium dioxide (B) with an average particle size of 1 µm or less.

[0194] The mean particle size of the titanium dioxide (B) is preferably 1 µm or less, more preferably 800 nm or less, more preferably 500 nm or less, and more preferably 300 nm or less. The smaller the mean particle size, the greater the surface area per unit volume, thereby increasing the effect relative to the amount added. The mean particle size can be 1 nm or more.

[0195] The method for measuring the mean particle size of titanium dioxide (B) is not particularly limited, but can be measured using dynamic light scattering or laser light scattering methods.

[0196] The amount of titanium dioxide (B) added is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 0.6 parts by mass or more and 9.0 parts by mass or less, more preferably 0.7 parts by mass or more and 8 parts by mass or less, more preferably 0.8 parts by mass or more and 7 parts by mass or less, and particularly preferably 0.9 parts by mass or more and 6 parts by mass or less, per 100 parts by mass of the thermoplastic resin (A). Excessive addition of titanium dioxide (B) can reduce the toughness of the resin composition. Furthermore, too much titanium dioxide (B) near the surface can block the laser beam, thereby reducing the proportion of the laser beam that penetrates the interior of the molded product and thus decreasing the clarity of printed markings with dyes that change color under laser light.Conversely, if too little titanium dioxide (B) is added, there is not enough titanium dioxide to change the color, resulting in reduced contrast in the printed section.

[0197] The crystal form of titanium dioxide (B) is not particularly limited, but the rutile type or the anatase type is preferred, with the thermally stable rutile type being particularly preferred.

[0198] The surface treatment of titanium dioxide (B) is not particularly limited, but the titanium dioxide (B) is preferably treated with substances such as aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), stearic acid, or alkylsilanes. Such surface treatment can improve the dispersibility of the titanium dioxide (B) in the resin, increase its weather resistance, and impart excellent properties to the resin molded article.

[0199] The oil absorption capacity of titanium dioxide (B) is not particularly limited, but it is preferably 5 g / 100 g or more, more preferably 10 g / 100 g or more, more preferably 15 g / 100 g or more, and more preferably 20 g / 100 g or more (oil used for measurement: boiled linseed oil). A high oil absorption capacity indicates a large surface area per unit volume, which increases the effect relative to the amount added. [Filler (C)]

[0200] The resin composition preferably contains, in addition to the thermoplastic resin (A) and the titanium dioxide (B), a filler (C). The inclusion of the filler (C) results in a resin composition with improved mechanical properties, such as strength and stiffness. The filler (C) refers to components other than the thermoplastic resin (A) and the titanium dioxide (B).

[0201] Examples of filler (c) include, but are not limited to, glass fibers, carbon fibers, calcium silicate fibers, potassium titanate fibers, aluminum borate fibers, glass flakes, calcium carbonate, talc, kaolin, mica, hydrotalcite, zinc carbonate, calcium hydrogen phosphate, wollastonite, zeolite, boehmite, magnesium oxide, calcium silicate, sodium aluminosilicate, magnesium silicate, Ketjen carbon black, acetylene carbon black, furnace carbon black, carbon nanotubes, graphite, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, montmorillonite, swellable fluorophlogopite, apatite and ground fibers.

[0202] One type of these fillers (C) can be used alone, or two or more types can be used in combination.

[0203] Of these, glass fibers, carbon fibers, glass flakes, talc, kaolin, mica, calcium hydrogen phosphate, wollastonite, carbon nanotubes, graphite, calcium fluoride, montmorillonite, expandable fluorinated mica, or apatite are preferred as filler (C) with regard to stiffness and strength. One or more of the following materials are particularly preferred as filler (C): glass fibers, calcium carbonate, talc, mica, wollastonite, and ground fibers. Glass fibers or carbon fibers are preferred, and glass fibers are particularly preferred.

[0204] If the filler (C) consists of glass fibers or carbon fibers, the number-average fiber diameter (d1) is preferably 3 µm or more and 30 µm or less. Furthermore, the weight-average fiber length (L) is preferably 100 µm or more and 5 mm or less. Additionally, fibers with an aspect ratio ((L) / (d1)) of the number-average fiber diameter (d1) to the weight-average fiber length (L) of 3 or more and 100 or less are preferred. Higher performance can be achieved by using glass fibers or carbon fibers in the above structure.

[0205] If the filler (C) consists of glass fibers, it is also preferable that the number-average fiber diameter (d1) be 3 µm or more and 30 µm or less. The weight-average fiber length (L) is preferably 103 µm or more and 5 mm or less. Furthermore, fibers with an aspect ratio ((L) / (d)) of 10 or more and 100 or less are preferable.

[0206] The number-averaged fiber diameter and the weight-averaged fiber length of the filler (C) can be measured according to the following procedure.

[0207] First, a molded article is dissolved in a solvent such as formic acid in which the thermoplastic resin (A) is soluble. Then, from the resulting insoluble components, e.g., 100 or more fillers (C) are randomly selected. The filler (C) is then observed using a light microscope or a scanning electron microscope, and the number-mean fiber diameter can be determined by dividing the total measured fiber diameters by the number of fillers (C) measured. Alternatively, the weight-mean fiber length can be determined by dividing the total measured fiber length by the total measured weight of the filler (C).

[0208] The resin composition preferably contains more than 0 parts by mass and 150.0 parts by mass or less of the filler (C), more preferably 10.0 parts by mass or more and 140.0 parts by mass or less of the filler (C), more preferably 20.0 parts by mass or more and 135.0 parts by mass or less of the filler (C), particularly preferably 25.0 parts by mass or more and 130.0 parts by mass or less of the filler (C), and most preferably 30.0 parts by mass or more and 100.0 parts by mass or less of the filler (C), per 100 parts by mass of the thermoplastic resin (A).

[0209] If the filler content (C) is at or above the lower limit described above, the mechanical properties, such as strength and stiffness, of the molded part tend to be further improved. Conversely, if the filler content (C) is at or below the upper limit described above, the molded part tends to exhibit a superior surface appearance.

[0210] In particular, if the filler (C) consists of glass fibers and their content is within the above-mentioned range per 100 parts by mass of the thermoplastic resin (A), the mechanical properties such as strength and stiffness of the molded article tend to be improved even further. [Flame retardant (D)]

[0211] Preferably, the resin composition contains, in addition to the thermoplastic resin (A) and the titanium oxide (B), a flame retardant (D). The flame retardant (D) is a different component than the thermoplastic resin (A), the titanium oxide (B), and the filler (C).

[0212] There are no special restrictions on the flame retardant (D), and examples include phosphorus-based flame retardants that do not contain halogen elements.

[0213] One of these flame retardants (D) can be used alone, or two or more can be used in combination. Furthermore, the flame-retardant properties can be further improved by using the flame retardant (D) in combination with a flame-retardant additive.

[0214] The range of phosphorus-based flame retardants is not particularly limited, and any flame retardant that does not contain halogens and does contain phosphorus can be used. Examples of phosphorus-based flame retardants include phosphate ester-based flame retardants, melamine polyphosphate-based flame retardants, phosphazene-based flame retardants, phosphinic acid-based flame retardants, and red phosphorus-based flame retardants.

[0215] Among these, the flame retardant (D) is preferably a phosphate ester-based flame retardant, a melamine polyphosphate-based flame retardant, a phosphazene-based flame retardant or a phosphinic acid-based flame retardant, particularly preferably a phosphinic acid-based flame retardant.

[0216] Examples of phosphinic acid-based flame retardants include, in particular, phosphinate salts and diphosphinate salts. Preferably, the flame retardant (D) is at least one selected from the group consisting of a phosphinate salt and a diphosphinate salt.

[0217] Examples of phosphinate salts include compounds represented by the following formula (I) (hereinafter sometimes referred to as ‘phosphinate salt (I)’).

[0218] Examples of diphosphinate salts include diphosphinate salts of the following formula (II) (hereinafter referred to as “diphosphinate salt (II)”).

[0219] In formula (I) R 11 and R 12 Each independently comprises an alkyl group with 1 or more and 6 or fewer carbon atoms, or an aryl group with 6 or more and 10 or fewer carbon atoms. M n11+ is an n11-valent metal ion. M is an element of group 2 or group 15 of the periodic table, a transition element, zinc, or aluminum. n11 is 2 or 3. The respective occurrences of R 11 and R 12 They can be the same or different.

[0220] In formula (II) R 21 and R 22 Each independently comprises an alkyl group with 1 or more and 6 or fewer carbon atoms, or an aryl group with 6 or more and 10 or fewer carbon atoms. Y 21 is an alkylene group with 1 or more and 10 or fewer carbon atoms, or an arylene group with 6 or more and 10 or fewer carbon atoms. M' x m21+ is an m21-valent metal ion. M' is an element of group 2 or group 15 of the periodic table, a transition element, zinc, or aluminum. n21 is an integer of 1 or more and 3 or less. If n21 is 2 or 3, the respective occurrences of R can 21 , R 22 and Y 21 They can be the same or different. m21 is 2 or 3. x is 1 or 2. If x is 2, the occurrences of M' can each be identical or different. n21, x, and m21 are integers that satisfy the relation: 2 × n21 = m21 × x. (R 11 , R 12 , R 21 and R 22 )

[0221] R 11 , R 12 , R 21 and R 22 Each of these is independently an alkyl group with 1 or more and 6 or fewer carbon atoms, or an aryl group with 6 or more and 10 or fewer carbon atoms. The respective occurrences of R 11 and R 12 They can be the same or different; however, for the sake of simplicity, it is preferable that they be the same. If n21 is equal to 2 or 3, the residues of R can be 21 and R 22 They may be the same or different; however, for the sake of simplifying production, it is preferable that they be the same.

[0222] The alkyl group can be linear or cyclic, but preferably linear. The linear alkyl group can be either straight-chain or branched. Examples of straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl groups. Examples of branched alkyl groups include 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl and 1,1,2-trimethylpropyl groups.

[0223] Examples of aryl groups include phenyl and naphthyl groups.

[0224] The alkyl group and the aryl group can have substituents. Examples of substituents on the alkyl group include aryl groups with 6 or more and 10 or fewer carbon atoms. Examples of substituents on the aryl group include alkyl groups with 1 or more and 6 or fewer carbon atoms.

[0225] Specific examples of alkyl groups with substituents include benzyl groups.

[0226] Specific examples of aryl groups with substituents include tolyl groups and xylyl groups.

[0227] Among these are R 11 , R 12 , R 21 and R 22 preferably alkyl groups with 1 or more and 6 or fewer carbon atoms, with methyl or ethyl groups being more preferred. (Y 21 )

[0228] Y 21 is an alkylene group with 1 or more and 10 or fewer carbon atoms, or an arylene group with 6 or more and 10 or fewer carbon atoms. If n21 is 2 or 3, the occurrences of Y can 21 They may be the same or different; however, for the sake of simplifying production, it is preferable that they be the same.

[0229] The alkylene group can be either linear or cyclic, although a linear alkylene group is preferred. The linear alkylene group can be straight-chain or branched. Examples of straight-chain alkylene groups include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups. Examples of branched alkylene groups include 1-methylethylene and 1-methylpropylene groups.

[0230] Examples of arylene groups include phenylene and naphthylene groups.

[0231] The alkylene and arylene groups can have substituents. Examples of substituents on the alkylene group include aryl groups with 6 or more and 10 or fewer carbon atoms. Examples of substituents on the arylene group include alkyl groups with 1 or more and 6 or fewer carbon atoms.

[0232] Specific examples of alkylene groups with substituents include phenylmethylene, phenylethylene, phenyltrimethylene, and phenyltetramethylene groups.

[0233] Specific examples of arylene groups with substituents include methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene and tert-butylnaphthylene.

[0234] Among these is Y 21 preferably an alkylene group with 1 or more and 10 or fewer carbon atoms, with methylene or ethylene groups being more preferred. (M and M')

[0235] M and M' are each independently an ion of an element from Group 2 or Group 15 of the periodic table, a transition metal ion, a zinc ion, or an aluminum ion. Examples of ions of elements belonging to Group 2 of the periodic table are calcium ions and magnesium ions. Examples of ions of elements belonging to Group 15 of the periodic table are bismuth ions.

[0236] If x equals 2, the occurrences of M' can be the same or different; however, for the sake of simplicity in production, it is preferable that they be the same.

[0237] Among these, M and M' are preferably calcium, zinc or aluminium, with calcium or aluminium being preferred. (x)

[0238] x represents the number of M' and is either 1 or 2. x can be selected according to the type of M' and the number of diphosphinic acids. (n11 and n21)

[0239] n11 represents the number of phosphinic acid groups and the valence of M and is either 2 or 3. n11 can be chosen accordingly depending on the type and valence of M.

[0240] n21 represents the number of diphosphinic acid groups and is an integer of 1 or more and 3 or less. n21 can be selected appropriately depending on the type and valence of M'. (m21)

[0241] m21 represents the value of M' and is either 2 or 3.

[0242] n21, x and m21 are integers that satisfy the following relation formula: 2 × n21 = m21 × x.

[0243] Specific examples of preferred phosphinate salts (I) include dimethylphosphinic acid calcium, dimethylphosphinic acid magnesium, dimethylphosphinic acid aluminum, dimethylphosphinic acid zinc, ethylmethylphosphinic acid calcium, ethylmethylphosphinic acid magnesium, ethylmethylphosphinic acid aluminum, ethylmethylphosphinic acid zinc, diethylphosphinic acid calcium, diethylphosphinic acid magnesium, diethylphosphinic acid aluminum, diethylphosphinic acid zinc, methyl-n-propylphosphinic acid calcium, methyl-n-propylphosphinic acid magnesium, methyl-n-propylphosphinic acid aluminum, methylphenylphosphinic acid calcium, methylphenylphosphinic acid magnesium, methylphenylphosphinic acid aluminum, Methylphenylphosphinic acid zinc, diphenylphosphinic acid calcium, diphenylphosphinic acid magnesium, diphenylphosphinic acid aluminum and diphenylphosphinic acid zinc.The phosphinate salts (I) are preferably dimethylphosphinic acid calcium, dimethylphosphinic acid aluminum, diethylphosphinic acid calcium or diethylphosphinic acid aluminum, more preferably diethylphosphinic acid calcium or diethylphosphinic acid aluminum and particularly preferably diethylphosphinic acid aluminum because of its excellent flame-retardant properties.

[0244] Specific examples of preferred diphosphinate salts (II) include methanedi(methylphosphinic acid)-calcium, methanedi(methylphosphinic acid)-magnesium, methanedi(methylphosphinic acid)-aluminium, methanedi(methylphosphinic acid)-zinc, benzene-1,4-di(methylphosphinic acid)-calcium, benzene-1,4-di(methylphosphinic acid)-magnesium, benzene-1,4-di(methylphosphinic acid)-aluminum and benzene-1,4-di(methylphosphinic acid)-zinc.

[0245] The flame retardant content (D) is preferably 5.0 parts by mass or more and 90.0 parts by mass or less, further preferably 10.0 parts by mass or more and 80.0 parts by mass or less, more preferably 15.0 parts by mass or more and 70.0 parts by mass or less and particularly preferably 20.0 parts by mass or more and 60.0 parts by mass or less, per 100 parts by mass of the thermoplastic resin (A).

[0246] If the flame retardant content is adjusted to the lower limit described above or higher, a resin composition with excellent flame-retardant properties can be obtained. Conversely, by adjusting the flame retardant content to the upper limit described above or lower, a resin composition with excellent flame-retardant properties can be obtained without impairing the inherent properties of the resin composition. [Antimony-based oxides]

[0247] The resin composition is free of antimony-based oxides.

[0248] Examples of antimony-based oxides are antimony trioxide (Sb₂O₃), antimony tetroxide, antimony pentoxide, and sodium antimonate. Preferably, the resin composition is free of compounds containing antimony elements. Preferably, the thermoplastic resin (A), the titanium dioxide (B), the filler (C), the flame retardant (D), the dye (E), and the other additives (F) are free of antimony compounds. [Colorant (E)]

[0249] The resin composition may contain a dye (E) in addition to the thermoplastic resin (A) and the titanium dioxide (B). The dye (E) is a separate component from the thermoplastic resin (A), the titanium dioxide (B), the filler (C), and the flame retardant (D).

[0250] Conventional dyes can be used as the colorant (E), so that the resin composition can be colored in any shade from white to black and in various colors. Preferably, the resin composition can be colored white, light gray, gray, dark gray, or in various colors (e.g., orange). The colorant (E) can be a dye that develops white, gray, or colored hues. The brightness (L*) of the colorant is preferably 25 or more, more preferably 35 or more, more preferably 45 or more, and more preferably 55 or more. Additionally, the colorant (E) is preferably added such that the brightness (L*) of the molded article is 25 or higher, preferably 35 or higher, more preferably 45 or higher, and more preferably 55 or higher.

[0251] Brightness is measured using a spectrophotometer. More precisely, the colorimetric measurement can be performed with a Suga Test Instruments Co., Ltd. SC-50µ colorimeter using D65 light at 10°.

[0252] With a view to improving the clarity of printed markings produced by laser marking, a laser-absorbing dye is preferred as the dye (E).

[0253] Examples of such dyes include carbon black (such as acetylene carbon black, lamp black, thermal carbon black, furnace black, sewer soot, Ketjen carbon black, gas carbon black, and oil carbon black), graphite, titanium carbon black, and black iron oxide. Among these, carbon black (E-1) is preferred from the perspectives of dispersibility, color development, and cost. These dyes can be used alone or in combination with two or more.

[0254] Various inorganic and organic pigments, listed below, can be used as non-black pigments. These non-black pigments can be used alone or in combination with other pigments.

[0255] Examples of inorganic pigments include white pigments such as calcium carbonate, zinc oxide, and zinc sulfide; yellow pigments such as cadmium yellow, lead yellow, titanium yellow, zinc chromate, ochre, and yellow iron oxide; red pigments such as red base pigments, amber, red iron oxide, and cadmium red; blue pigments such as Prussian blue, ultramarine, and cobalt blue; and green pigments such as chrome green.

[0256] Examples of organic pigments are pigments based on azo, azomethine, methine, indanthrone, anthraquinone, pyranthrone, flavanthrone, benzanthrone, phthalocyanine, quinophthalone, perylene, perinone, dioxazine, thioindigo, isoindolinone, isoindolin, pyrrole, and quinacridone.

[0257] The dye content (E) is preferably 0.0001 parts by mass or more and 5.0000 parts by mass or less, more preferably 0.0005 parts by mass or more and 2.5000 parts by mass or less, and even more preferably 0.0010 parts by mass or more and 1.0000 parts by mass or less, per 100 parts by mass of the thermoplastic resin (A). If the dye content (E) is at or above the lower limit described above, the heating efficiency by laser is further improved and the clarity is further increased. On the other hand, if the dye content (E) is at or below the upper limit described above, it is possible to more effectively prevent the deterioration of the properties and carbonization of the resin due to heating. [Other additives (F)]

[0258] In addition to the thermoplastic resin (A) and the titanium oxide (B), the resin composition may also contain other additives (F) commonly used in resin compositions, provided that the effects exhibited by the molded article of the present embodiment are not impaired. Examples of other additives (F) include moldability enhancers, degradation inhibitors, nucleation agents, and heat stabilizers.

[0259] The content of other additives (F) in the resin composition varies depending on the type and application of the composition, and there is no particular restriction as long as the effects exhibited by the molded article of the present embodiment are not impaired.

[0260] The other additives (F) are components other than the thermoplastic resin (A), the titanium dioxide (B), the filler (C), the flame retardant (D) and the dye (E). (Means to improve malleability)

[0261] The agents used to improve malleability are not particularly limited and include, for example, higher fatty acids, metal salts of higher fatty acids, esters of higher fatty acids, and amides of higher fatty acids. It should be noted that malleability-enhancing agents also act as lubricants. (1) Higher fatty acids

[0262] Examples of higher fatty acids include straight-chain or branched, saturated or unsaturated aliphatic monocarboxylic acids with 8 or more and 40 or fewer carbon atoms.

[0263] Examples of straight-chain saturated aliphatic monocarboxylic acids with 8 or more and 40 or fewer carbon atoms include lauric acid, palmitic acid, stearic acid, behenic acid, and montanic acid.

[0264] Examples of branched saturated aliphatic monocarboxylic acids with 8 or more and 40 or fewer carbon atoms include isopalmitic acid and isostearic acid.

[0265] Examples of straight-chain unsaturated aliphatic monocarboxylic acids with 8 or more and 40 or fewer carbon atoms include oleic acid and erucic acid.

[0266] Examples of branched, unsaturated aliphatic monocarboxylic acids with 8 or more and 40 or fewer carbon atoms include isolic acid.

[0267] Among these, stearic acid or montanic acid is preferred as a higher fatty acid. (2) Metal salts of higher fatty acids

[0268] Metal salts of higher fatty acids are metal salts of higher fatty acids.

[0269] Examples of metallic elements in metal salts include the elements of Group 1, Group 2 and Group 3 of the periodic table, as well as zinc and aluminum.

[0270] Examples of elements in Group 1 of the periodic table include sodium and potassium.

[0271] Examples of elements in Group 2 of the periodic table include calcium and magnesium.

[0272] Examples of elements in Group 3 of the periodic table include scandium and yttrium.

[0273] Among these, the elements of Group 1 and 2 or aluminium are preferred, with sodium, potassium, calcium, magnesium or aluminium being more strongly preferred.

[0274] Specific examples of metal salts of higher fatty acids are calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, and calcium palmitate.

[0275] Among these, metal salts of montanic acid or stearic acid are preferred. (3) Esters of higher fatty acids

[0276] An ester of a higher fatty acid is an esterification product of a higher fatty acid and an alcohol.

[0277] A preferred ester of a higher fatty acid is an ester of an aliphatic carboxylic acid with 8 or more and 40 or fewer carbon atoms and an aliphatic alcohol with 8 or more and 40 or fewer carbon atoms.

[0278] Examples of aliphatic alcohols with 8 or more and 40 or fewer carbon atoms include stearyl alcohol, behenyl alcohol, and lauryl alcohol.

[0279] Specific examples of higher fatty acid esters include stearyl stearate and behenyl behenate. (4) Amides of higher fatty acids

[0280] An amide of a higher fatty acid is an amide compound of a higher fatty acid.

[0281] Examples of higher fatty acid amides include stearamide, oleamide, erucamide, ethylenebis(stearamide), ethylenebis(oleamide), N-stearylstearamide and N-stearyl-erucamide.

[0282] These higher fatty acids, metal salts of higher fatty acids, esters of higher fatty acids and amides of higher fatty acids can be used alone or in combination of two or more. (Decomposition inhibitors)

[0283] Decomposition inhibitors are used to prevent thermal decomposition and discoloration during heating and to improve heat aging resistance.

[0284] Although decomposition inhibitors are not particularly limited, examples include copper compounds, phenolic stabilizers, phosphite-based stabilizers, hindered amine-based stabilizers, triazine-based stabilizers, benzotriazole-based stabilizers, benzophenone-based stabilizers, cyanoacrylate-based stabilizers, salicylate-based stabilizers, and sulfur-based stabilizers.

[0285] Examples of copper compounds include copper acetate and copper iodide.

[0286] An example of a phenolic stabilizer is a sterically hindered phenol compound.

[0287] One of these decomposition inhibitors can be used alone, or two or more can be used in combination. (Nutting agent)

[0288] A nucleating agent is a substance that, when added, has at least one of the following effects: (1) the effect of increasing the crystallization peak temperature of the resin composition; (2) the effect of reducing the difference between the extrapolated initial and final temperatures of the crystallization peak; and (3) the effect of refining or standardizing the size of the spherulites in the resulting molded article.

[0289] Examples of nucleating agents include talc, boron nitride, mica, kaolin, silicon nitride, carbon black, potassium titanate and molybdenum disulfide.

[0290] A nucleating agent can be used alone, or two or more nucleating agents can be used in combination.

[0291] From the perspective of the effect of nucleating agents, talc or boron nitride is preferred among these.

[0292] To achieve a better effect of the nucleating agents, the number-average particle size of the nucleating agents is preferably 0.01 µm or more and 10 µm or less.

[0293] The number-mean particle size of a nucleating agent can be measured using the following method. First, a molded article is dissolved in a solvent such as formic acid, which dissolves the resin composition. Then, 100 or more nucleating agent particles are randomly selected from the resulting insoluble components. The particle sizes of the nucleating agent particles are then measured using an optical microscope or a scanning electron microscope.

[0294] The content of the nucleating agent in the resin composition is preferably 0.001 parts by mass or more and 1 part by mass or less, more preferably 0.001 parts by mass or more and 0.5 parts by mass or less, and more preferably 0.001 parts by mass or more and 0.09 parts by mass or less, per 100 parts by mass of the thermoplastic resin (A).

[0295] If the nucleating agent content is at or above the lower limit described above, the heat resistance of the molded part tends to be improved. Conversely, if the content is at or below the upper limit described above, a molded part with excellent toughness can be obtained. (Heat stabilizer)

[0296] Although the heat stabilizer is not particularly limited, examples include phenolic heat stabilizers, phosphorus-based heat stabilizers, amine-based heat stabilizers, and metal salts of elements from groups 3, 4, and 11 to 14 of the periodic table. (1) Phenolic heat stabilizers

[0297] Examples of phenolic heat stabilizers include hindered phenolic compounds. Hindered phenolic compounds have properties that give resins such as polyamide and fibers excellent heat and light resistance.

[0298] Examples of hindered phenolic compounds include N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide), triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, and 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester. 1,3,5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and 1,3,5-Tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, for example.

[0299] One of these hindered phenol compounds can be used alone, or two or more of them can be used in combination.

[0300] When a phenolic heat stabilizer is used, the content of the phenolic heat stabilizer in the resin composition is preferably 0.01 wt% or more and 1 wt% or less, and more preferably 0.05 wt% or more and 1 wt% or less per total mass of the resin composition.

[0301] By adjusting the content of the phenolic heat stabilizer within the above-mentioned range, the heat aging resistance of the molded article can be further improved and gas formation further reduced. (2) Phosphorus-based heat stabilizers

[0302] Examples of phosphorus-based heat stabilizers include, but are not limited to: pentaerythrite-type phosphite compounds, trioctyl phosphite, trilaurel phosphite, tridecyl phosphite, octyldiphenyl phosphite, tris(isodecyl) phosphite, phenyldiisodecyl phosphite, phenyldi(tridecyl) phosphite, diphenylisooctyl phosphite, diphenylisodecyl phosphite, diphenyl(tridecyl) phosphite, triphenyl phosphite, tris(nonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butyl-5-methylphenyl) phosphite, tris(butoxyethyl) phosphite, and 4,4'-butylidenebis(3-methyl-6-tert-butylphenyl-tetra-tridecyl) diphosphite. Tetra(C12-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, 4,4'-isopropylidenebis(2-tert-butylphenyl)di(nonylphenyl) phosphite, tris(biphenyl) phosphite, Tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane diphosphite, Tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6-tert-butylphenyl)diphosphite, Tetra(C1-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite,Tris(mixed mono- and di-nonylphenyl)phosphite, 4,4'-isopropylidenebis(2-tert-butylphenyl)di(nonylphenyl)phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, Tris(3,5-di-tert-butyl-4-hydroxyphenyl)phosphite, hydrogenated 4,4'-isopropylidenediphenylpolyphosphite, Bis(octylphenyl)-bis(4,4'-butylidenebis(3-methyl-6-tert-butylphenyl))-1,6-hexanedioldiphosphite, Hexatridecyl-1,1,3-Tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butanetriphosphite, Tris(4,4'-isopropylidenebis(2-tert-butylphenyl))phosphite Tris(1,3-distearoyloxyisopropyl) phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, 2,2'-methylenebis(3-methyl-4,6-di-tert-butylphenyl)-2-ethylhexyl phosphite, Tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, for example.

[0303] One of these phosphorus-based heat stabilizers can be used alone, or two or more can be used in combination.

[0304] Beispiele für Phosphitverbindungen vom Pentaerythrit-Typ umfassen unter anderem: 2,6-Di-tert-butyl-4-methylphenyl-phenyl-pentaerythrit-diphosphit, 2,6-Di-tert-butyl-4-methylphenyl-methyl-pentaerythrit-diphosphit, 2,6-Di-tert-butyl-4-methylphenyl-2-ethylhexyl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-isodecyl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-lauryl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-isotridecyl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-stearyl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-cyclohexyl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-benzyl-pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-ethylcellosolve pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-butyl-carbit pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-octylphenyl-Pentaerythritdiphosphit, 2,6-Di-tert-butyl-4-methylphenyl-nonylphenyl-Pentaerythritdiphosphit, Bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,6-di-tert-butylphenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,4-di-tert-butylphenyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,4-di-tert-octylphenyl pentaerythritol diphosphite, 2,6-Di-tert-butyl-4-methylphenyl-2-cyclohexylphenyl pentaerythritol diphosphite, 2,6-Di-tert-amyl-4-methylphenyl-phenyl-pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl)-pentaerythritol diphosphite and bis(2,6-di-tert-octyl-4-methylphenyl)-pentaerythritol diphosphite, for example.

[0305] One of these phosphite compounds of the pentaerythritol type can be used alone, or two or more of them can be used in combination.

[0306] When a phosphorus-based heat stabilizer is used, the content of the phosphorus-based heat stabilizer in the resin composition is preferably 0.01 wt% or more and 1 wt% or less, and more preferably 0.05 wt% or more and 1 wt% or less, based on the total mass of the resin composition.

[0307] By adjusting the content of the phosphorus-based heat stabilizer within the above-mentioned range, the heat aging resistance of the molded part can be further improved and gas formation further reduced. (3) Amine-based heat stabilizers

[0308] Beispiele für Hitzestabilisatoren auf Aminbasis umfassen unter anderem 4-Acetoxy-2,2,6,6-tetramethylpiperidin, 4-Stearoyloxy-2,2,6,6- tetramethylpiperidin, 4-Acryloyloxy-2,2,6,6-tetramethylpiperidin, 4-(Phenylacetoxy)-2,2,6,6-Tetramethylpiperidin, 4-Benzoyloxy-2,2,6,6-Tetramethylpiperidin, 4-Methoxy-2,2,6,6-Tetramethylpiperidin, 4-Stearoxy-2,2,6,6-Tetramethylpiperidin, 4-Cyclohexyloxy-2,2,6,6-Tetramethylpiperidin, 4-Benzyloxy-2,2,6,6-Tetramethylpiperidin, 4-Phenoxy-2,2,6,6-Tetramethylpiperidin, 4-(Ethylcarbamoyloxy)-2,2,6,6-Tetramethylpiperidin, 4-(Cyclohexylcarbamoyloxy)-2,2,6,6-Tetramethylpiperidin, 4-(Phenylcarbamoyloxy)-2,2,6,6-tetramethylpiperidin, Bis(2,2,6,6-tetramethyl-4-piperidyl)-carbonat, Bis(2,2,6,6-tetramethyl-4-piperidyl)-oxalat, Bis(2,2,6,6-tetramethyl-4-piperidyl)-malonat, Bis(2,2,6,6-Tetramethyl-4-piperidyl)-sebacat, Bis(2,2,6,6-tetramethyl-4-piperidyl)-adipat, Bis(2,2,6,6-tetramethyl-4-piperidyl)-terephthalat, 1,2-Bis(2,2,6,6-tetramethyl-4-piperidyloxy)-ethan, α,α'-Bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-xylene, bis(2,2,6,6-tetramethyl-4-piperidyl)-toluene-2,4-dicarbamate, bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylene-1,6-dicarbamate, Tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,5-tricarboxylate, Tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,4-tricarboxylate, 1-[2-{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl} butyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl] 2,2,6,6-Tetramethylpiperidine, a condensate of 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5)undecane]-diethanol, for example.

[0309] One of these amine-based heat stabilizers can be used alone, or two or more can be used in combination.

[0310] When an amine-based heat stabilizer is used, the content of the amine-based heat stabilizer in the resin composition is preferably 0.01 wt% or more and 1 wt% or less, and more preferably 0.05 wt% or more and 1 wt% or less, based on the total mass of the resin composition.

[0311] By adjusting the content of the amine-based heat stabilizer within the above-mentioned range, the heat aging resistance of the molded article can be further improved and gas formation further reduced. (4) Metal salts of the elements of groups 3, 4 and 11 to 14 of the periodic table

[0312] Metal salts of elements from groups 3, 4 and 11 to 14 of the periodic table are not restricted, as long as they are salts of metals belonging to these groups.

[0313] Of these, copper salts are preferable from the perspective of further improving the heat aging resistance of the molded part. Examples of such copper salts include, among others, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, and copper complex salts in which the copper is coordinated to chelating agents, for example.

[0314] Examples of chelating agents include ethylenediamine and ethylenediaminetetraacetic acid.

[0315] One of these copper salts can be used alone, or two or more of them can be used in combination.

[0316] Among these, copper acetate is preferred as a copper salt. Using a copper salt allows for a resin composition with improved heat aging resistance and more effective control of metal corrosion of the screw and barrel during extrusion (hereinafter referred to simply as "metal corrosion").

[0317] When a copper salt is used as a heat stabilizer, the content of the copper salt in the resin composition is preferably 0.01 parts by mass or more and 0.60 parts by mass or less, and more preferably 0.02 parts by mass or more and 0.40 parts by mass or less, per 100 parts by mass of the thermoplastic resin (A).

[0318] By adjusting the copper salt content within the above-mentioned range, the heat aging resistance of the molded article can be further improved, while copper precipitation and metal corrosion are more effectively suppressed.

[0319] From the perspective of improving the heat aging resistance of the formed product, the concentration of the copper element derived from the above copper salt is preferably 10 parts by mass or more and 2000 parts by mass or less, more preferably 30 parts by mass or more and 1500 parts by mass or less, and even more preferably 50 parts by mass or more and 500 parts by mass or less, based on 10 6 Mass parts (millions of mass parts) of the thermoplastic resin (A).

[0320] One of the heat stabilizer components described above can be used alone, or two or more of them can be used in combination. [Method for producing a resin composition]

[0321] The process for producing the resin composition is not particularly limited as long as it involves mixing the individual components, namely the thermoplastic resin (A) with the titanium dioxide (B) and, if necessary, the filler (C), the flame retardant (D), the dye (E), and other additives (F). Hereinafter, the thermoplastic resin (A), the titanium dioxide (B), the filler (C), the flame retardant (D), the dye (E), and other additives (F) will also be referred to as component (A), component (B), component (C), component (D), component (E), and component (F), respectively.

[0322] Examples of mixing processes for components (A) and (B) and, where necessary, components (C) to (F) include the following processes: (1) A process in which components (A) and (B) and optionally components (C) to (F) are mixed with a Henschel mixer or the like and then fed to a single or twin screw extruder for melt kneading. (2) A process in which a mixture of components other than component (C) is premixed using a Henschel mixer or the like, the mixture obtained is fed to a single-screw or twin-screw extruder for melt kneading and then, if necessary, component (C) is added via the side feed of the extruder. (3) A method that combines the methods described in (1) and (2).

[0323] The method for feeding the components of the resin composition to the hot melt kneading machine can be carried out by simultaneously feeding all components to the same feed opening or by feeding the components from different feed openings.

[0324] If the polyamide (A1) contains an aliphatic polyamide (A1-1), the melting temperature is preferably at least 1°C and at most 100°C higher than the melting point of the aliphatic polyamide (A1-1), more preferably at least 10°C and at most 50°C higher than the melting point of the aliphatic polyamide (A1-1).

[0325] The shearing speed in the kneading machine is preferably about 100 seconds. -1 or more. In addition, the average dwell time during kneading is preferably 0.5 minutes or more and 5 minutes or less.

[0326] A known device can be used as a device for melt kneading, such as single or twin screw extruders, Banbury mixers and melt kneading machines (mixing rollers).

[0327] The respective quantities of the components in the resin composition are the same as the respective quantities of the components in the resin composition described above. [Physical properties of the resin composition]

[0328] The glass transition temperature Tg of the resin composition is preferably 75°C or higher, more preferably 75°C or higher and 220°C or lower, more preferably 80°C or higher and 200°C or lower, further preferably 85°C or higher and 180°C or lower, particularly preferably 90°C or higher and 160°C or lower, and most preferably 92°C or higher and 150°C. It is preferably 90°C or higher.

[0329] If the glass transition temperature Tg of the resin composition is within the range of numbers described above, the resulting molded article exhibits excellent gloss and improved clarity of the printed markings produced by laser marking.

[0330] The glass transition temperature Tg of the resin composition can be measured, for example, with a device for measuring dynamic viscoelasticity.

[0331] For example, if a measurement is performed at a frequency of 8 Hz while the resin composition is heated from -100°C to 250°C at a heating rate of 3°C / min, the temperature at the peak of the measurement, where the storage modulus decreases significantly and the loss modulus reaches its maximum, is defined as the glass transition temperature Tg. More precisely, the temperature at which tanδ reaches its maximum point is defined as the glass transition temperature Tg, where tanδ is the ratio (E2 / E1) of the loss modulus E2 to the storage modulus E1. If two or more loss modulus peaks are observed, the peak temperature of the highest temperature peak is assumed to be the glass transition temperature Tg. For this measurement, the measurement frequency must be at least once every 20 seconds to increase accuracy.

[0332] Although there are no specific restrictions regarding the manufacturing process of the test specimen, the specimen is preferably prepared in accordance with JIS-K7139. To eliminate the effects of mold deformation, a section of a thermoformed part is preferably used. From a thermal conductivity perspective, it is advantageous for the dimensions (width and thickness) of the section to be as small as possible.

[0333] The crystallization peak temperature of the resin composition is preferably 240°C or lower, more preferably 240°C or lower or not present, more preferably 120°C or higher and 235°C or lower or not present, more preferably 140°C or higher and 230°C or lower or not present, and particularly preferably 160°C or higher and 225°C or lower or not present.

[0334] Ensuring that the crystallization peak temperature of the resin composition falls within the range described above results in excellent gloss and improved clarity of the printed markings produced by laser marking on the molded part. A lack of a peak temperature indicates a significant influence of the amorphous resin component.

[0335] The crystallization peak temperature of the resin composition can be measured, for example, using DSC.

[0336] Specifically, for example, the temperature at the peak of the observed endothermic peak is defined as the crystallization peak temperature when the resin composition is heated from 40°C to 300°C at a heating rate of 20°C / min and held at 300°C for 3 minutes, then cooled from 300°C to 40°C at a cooling rate of 20°C / min, held at 40°C for 3 minutes, reheated from 40°C to 300°C at a heating rate of 20°C / min, held at 300°C for 3 minutes, and then cooled again from 300°C to 40°C at a cooling rate of 20°C / min. If two or more endothermic peaks occur, the temperature at the peak of the highest endothermic peak is defined as the crystallization peak temperature. The crystallization peak temperature observed using this method was measured.

[0337] The enthalpy of the endothermic peak observed at this time is preferably 10 J / g or more, and more preferably 20 J / g or more. Furthermore, the sample should preferably be heated once during the measurement to a temperature of at least 20°C above the melting point to melt the resin, and then cooled to 23°C at a cooling rate of 10°C / min before use. <Verfahren zur Herstellung des Formartikels>

[0338] The molded article described above can be manufactured, for example, using the following method.

[0339] In particular, the method for manufacturing a molded article with an identification section of the present embodiment (hereinafter sometimes referred to as "the manufacturing method of the present embodiment") comprises performing a laser marking (hereinafter referred to as "the laser marking step") on a molded article formed by molding a resin composition comprising a thermoplastic resin (A) and titanium oxide (B).

[0340] The resin composition described in the above step has a light absorption capacity of 17% or less at a wavelength of 355 nm when formed into a shaped product with a thickness of 50 µm, and the laser marking is carried out such that the protrusion height of the identification section of the shaped article is 6.6 µm or less.

[0341] Since the manufacturing process of the present embodiment has the configuration described above, a molded article with a clearly printed section produced by laser marking can be obtained.

[0342] That is, the manufacturing process of the present embodiment can also be referred to as a laser marking process to give a molded article a clear, laser-marked printed section. [Laser marking step]

[0343] Examples of lasers used in laser marking include carbon dioxide lasers, Nd:YAG lasers, YAG lasers, ruby ​​lasers, semiconductor lasers, argon lasers, and excimer lasers. Nd:YAG lasers, YAG lasers, and semiconductor lasers are preferred in terms of marking performance.

[0344] The wavelength of the laser used is generally preferably 193 nm or more and 1100 nm or less, more preferably within one of the three wavelength bands of 300 nm or more and 400 nm or less, 500 nm or more and 600 nm or less or 900 nm or more and 1100 nm or less, more preferably within the two wavelength bands of 300 nm or more and 400 nm and 500 nm or more and 600 nm or less, and further preferably within the wavelength band of 300 nm or more and 400 nm or less.

[0345] By processing within these wavelength ranges, the color of the titanium oxide (B) that absorbs the laser changes to a blackish hue, thus making the contrast to the surrounding area clear.

[0346] From the perspective of reducing cycle time, the scanning speed of the laser marking is preferably 10 mm / s or more and 5000 mm / s or less, more preferably 100 mm / s or more and 4000 mm / s or less, even more preferably 200 mm / s or more and 3000 mm / s or less, and particularly preferably 500 mm / s or more and 2500 mm / s or less.

[0347] Setting the scan speed to the lower limit described above or higher prevents excessive laser irradiation of the titanium oxide (B), thus effectively preventing carbonization of the resin or foaming of the surface layer due to heating. This would obscure the discolored titanium oxide, potentially reducing contrast with the surrounding area and thus more effectively preventing the printed markings from becoming illegible. Conversely, setting the scan speed to the upper limit described above or lower prevents insufficient laser irradiation, effectively preventing a reduction in contrast with the surrounding area and thus more effectively preventing the printed markings from becoming unclear.

[0348] The processing power of the laser marking is preferably 0.01 W or more and 30.0 W or less, more preferably 0.05 W or more and 20.0 W or less, and even more preferably 0.1 W or more and 15.0 W or less.

[0349] Setting the processing power to the lower limit described above or higher prevents a reduction in contrast due to insufficient laser irradiation of the titanium oxide (B), thus more effectively preventing the printed markings from becoming unclear. Conversely, setting the processing power to the upper limit described above or lower prevents excessive laser absorption, thus effectively preventing carbonization of the resin or foaming of the surface layer due to heating, which could obscure the discolored titanium oxide and reduce the contrast with the surrounding area, thereby more effectively preventing the printed markings from becoming illegible.

[0350] The frequency of the laser marking is preferably 1 kHz or more and 1000 kHz or less, more preferably 5 kHz or more and 750 kHz or less, and even more preferably 10 kHz or more and 500 kHz or less.

[0351] Setting the frequency to the lower limit described above or higher enables seamless marking, resulting in uniform print density and improved contrast of the markings, thus more effectively preventing the printed markings from becoming illegible. Conversely, maintaining the frequency at or below the upper limit described above ensures that the irradiation energy per pulse remains above a certain level, preventing a reduction in laser irradiation on the titanium oxide (B), which would otherwise decrease the contrast difference with the surrounding area, thus more effectively preventing the printed markings from becoming illegible.

[0352] The distance for the laser marking is preferably 0.1 µm or more and 500 µm or less, more preferably 1 µm or more and 250 µm or less, and even more preferably 5 µm or more and 250 µm or less.

[0353] Maintaining the lower distance described above, or a greater distance, prevents excessively dense laser irradiation, which could lead to carbonization of the resin or foaming of the surface resin layer due to heating. This would obscure the discolored titanium oxide, potentially reducing contrast with the surrounding area and thus more effectively preventing the printed markings from becoming unclear. Conversely, adhering to the upper limit described above, or a smaller distance, ensures complete marking, resulting in uniform print density and improved contrast of the markings, thus more effectively preventing the printed markings from becoming unclear. [Shaping step]

[0354] The manufacturing process of the present embodiment may also include a shaping step prior to the laser marking step.

[0355] In the shaping step, the resin composition described above is formed to obtain a shaped intermediate article that does not have a printed section produced by laser marking (e.g. the identification section described above).

[0356] The process for manufacturing the shaped intermediate article is not particularly restricted, and known shaping processes can be used.

[0357] Examples of well-known forming processes include extrusion molding, injection molding, vacuum casting, blow molding, injection compression molding, decoration molding, twin injection molding, gas-assisted injection molding, expansion injection molding, low-pressure molding, ultra-thin injection molding (ultra-high-speed injection molding) and in-mold composite molding (insert molding and outsert molding).

[0358] The mold temperature during injection molding is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. Furthermore, the mold temperature is preferably 35°C or higher, more preferably 40°C or higher, and even more preferably 45°C or higher.

[0359] A lower mold temperature during injection molding reduces the crystallinity of the surface layer and increases the proportion of laser-sensitive dyes that penetrate into the interior of the molded product, thereby improving clarity.

[0360] However, if the mold temperature is extremely low (e.g., 30°C or lower), the surface layer solidifies before the pressure holding step during injection molding, resulting in an uneven surface. In this state, the surface roughness of the laser-marked section increases, causing light to scatter, which enhances the whiteness and suppresses the blackness of the discolored titanium oxide, leading to reduced contrast. [Method for producing the laser-marked molded article]

[0361] The method for producing a laser-marked molded article of the present embodiment comprises a step of performing a laser marking on a molded article formed by molding a resin composition containing a thermoplastic resin (A).

[0362] The resin composition has a light reflectance of 17% or less at a wavelength of 355 nm when formed into a shaped product with a thickness of 50 µm.

[0363] The resin composition may be similar to that of the molded article described above, and a similar resin composition is preferable. The molded article may be the molded article of the present embodiment described above. The laser marking step may include a step similar to the laser marking step in the method for manufacturing a molded article of the present embodiment described above, and a similar step is preferable.

[0364] The laser-marked molded article can be a molded article in which an identification section is provided using a laser. [Laser marking process]

[0365] The laser marking method of the present embodiment is a method for laser marking a molded article formed by molding a resin composition containing a thermoplastic resin (A).

[0366] The resin composition has a light reflectance of 17% or less at a wavelength of 355 nm when formed into a shaped product with a thickness of 50 µm.

[0367] The resin composition can be comparable to that of the molded article of the present embodiment described above, and a similar resin composition is preferable. The molded article can be the molded article of the present embodiment described above.

[0368] The laser marking process may include a step similar to the laser marking step in the molded article manufacturing process described above, and a similar step is preferable.

[0369] A molded article that has been laser-marked using the laser marking method of the present embodiment can be a molded article in which an identification section is provided by a laser. <Anwendung des Formartikels>

[0370] Since the molded article of the present embodiment has a clear printed section produced by laser marking, it can be used for various applications.

[0371] The molded article of the present embodiment is used, for example, in the automotive, electrical and electronics, machinery and industry, office equipment and aerospace sectors.

[0372] In particular, the molded article of the present embodiment is suitable as an electrical or electronic component, such as a housing for a magnetic switch, a housing for a circuit breaker, various switch components and a molded article for a connector.

[0373] Electromagnetic contactors, which open and close electrical circuits using an electromagnet; thermal relays, which interrupt electrical circuits in the event of an overload; electromagnetic switches, which combine these functions (and have several names, such as magnetic switches and air switches); and safety switches or residual current devices, which interrupt the power supply when a current exceeds a certain value or when anomalies such as vibration or overheating are detected (hereinafter collectively referred to as "circuit breakers"), are electrical or electronic components that are installed in electrical lines and are essential for ensuring the safety of electrical lines.

[0374] These electrical and electronic components require markings for product identification, connection markings to prevent installation errors, and safety-related markings. Conventionally, adhesive labels are used for such markings, but this method has limitations, such as the need for a smooth surface on the molded part. Therefore, the shift from conventional adhesive marking to laser marking is progressing for these products as well, and unambiguous marking characteristics are required.

[0375] This means that the molded article of the present embodiment is suitable for the electrical and electronic components described above, where clear marking features are required. EXAMPLES

[0376] The present revelation will be described in more detail below using specific examples and comparisons. However, the present revelation is not limited to the following examples.

[0377] The components of the resin composition used in the molded articles of the examples and comparison examples are described below. <komponenten>[Thermoplastic resin (A)] A1-1: Polyamide 66, aliphatic polyamide A1-2-1: Polyamide 6I, semi-aromatic polyamide A1-2-2: Polyamide 6I / 6T (manufactured by EMS, trade number: G21, isophthalic acid unit content in all dicarboxylic acid units of 70 mol%, molecular weight: 27,000), semi-aromatic polyamide A1-2-3: Polyamide 66 / 6I, copolymer, semi-aromatic polyamide A2: Polybutylene terephthalate [Titanium oxide (B)] B-1: Titanium oxide (rutile type, surface treatment agents: aluminum oxide, silicon dioxide, average particle size: 210 nm, oil absorption: 15 g / 100 g) [Filler (C)] C-1: Glass fibers (GF) (trade name: “ECS03T275H”, manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter: 10 µm, average fiber length: 3 mm) [Flame retardant (D)] D-1: Phosphinic acid-based flame retardant, aluminium diethylphosphinate (manufactured by Clariant, trade name: “Exolit OP1230”) D-2: Brominated polystyrene (manufactured by Chemtura Japan Limited, PBS-64HW) D-3: Antimony trioxide (manufactured by Yamanaka & Co., Ltd., GMA) [Colorant (E)] E-1: Soot (primary particle size: 27 nm) E-2: Zinc sulfide (particle size: 300 nm) E-3: Pigment Violet 15 <Herstellung von Polyamiden>

[0378] The processes for the preparation of an aliphatic polyamide A1-1, a semi-aromatic polyamide A1-2-1, and a semi-aromatic polyamide A1-2-3 are described below. The aliphatic polyamide A1-1, the semi-aromatic polyamide A1-2-1, and the semi-aromatic polyamide A1-2-3 obtained by the following preparation processes were dried in a nitrogen stream to adjust the moisture content to approximately 0.2 wt% before being used as raw materials for the resin compositions in the molded articles of the examples and comparative examples described later. [Synthesis example 1](Synthesis of aliphatic polyamide A1-1 (polyamide 66))

[0379] A polymerization reaction of the polyamide was carried out according to the "thermal melt polymerization process" as follows.

[0380] First, a 50 wt% homogeneous equimolar aqueous solution of crude monomers was prepared by dissolving 1500 g of an equimolar salt of adipic acid and hexamethylenediamine in 1500 g of distilled water. The aqueous solution was placed in a 5.4 L autoclave, which was then filled with nitrogen. The solution was then concentrated by gradually releasing steam until, with stirring, the concentration reached 70 wt% at a temperature of approximately 110°C or higher and 150°C or lower. The internal temperature was then increased to 220°C. At this point, the pressure in the autoclave was increased to 1.8 MPa. A reaction was initiated at 1.8 MPa for one hour until the internal temperature reached 245°C by gradually releasing steam for one hour. The pressure was then reduced over one hour.The interior of the autoclave was then maintained at a reduced pressure of 650 Torr (86.66 kPa) for 10 minutes using a vacuum device. At this point, the final polymerization temperature was 265°C. The resulting polymer was then extruded into strands through a bottom spinneret under nitrogen pressure. These strands were water-cooled, cut, and discharged as pellets. The pellets were then dried at 100°C for 12 hours under a nitrogen atmosphere to obtain an aliphatic polyamide A1-1 (polyamide 66). [Synthesis example 2](Synthesis of semi-aromatic polyamide (A1-2-1) (Polyamide 6I))

[0381] A polymerization reaction of the polyamide was carried out according to the "thermal melt polymerization process" as follows.

[0382] First, a 50 wt% homogeneous aqueous solution of crude monomers was prepared by dissolving 1500 g of an equimolar salt of isophthalic acid and hexamethylenediamine, 1.5 mol% excess of adipic acid (based on the total equimolar salt component), and 0.5 mol% acetic acid in 1500 g of distilled water. The solution was then concentrated by gradually releasing steam until, with stirring, the concentration reached 70 wt% at a temperature of approximately 110°C or higher and 150°C or lower. The internal temperature was then increased to 220°C. At this point, the pressure in the autoclave was increased to 1.8 MPa. While maintaining the pressure at 1.8 MPa, a reaction was initiated for one hour until the internal temperature reached 245°C by gradually releasing steam for one hour. The pressure was then reduced over 30 minutes.The interior of the autoclave was then maintained at a reduced pressure of 650 Torr (86.66 kPa) for 10 minutes using a vacuum device. At this point, the final polymerization temperature was 265°C. The resulting polymer was then extruded into strands through a bottom spinneret under nitrogen pressure. These strands were cooled with water, cut, and discharged as pellets. The pellets were then dried at 100°C for 12 hours under a nitrogen atmosphere to obtain a semi-aromatic polyamide (A1-2-1) (polyamide 6I). [Synthesis example 3](Synthesis of semi-aromatic polyamide A1-2-3 (Polyamide 66 / 6I))

[0383] A 5-liter autoclave was charged with 2.00 kg of an equimolar salt of adipic acid and hexamethylenediamine, 0.50 kg of an equimolar salt of isophthalic acid and hexamethylenediamine, and 2.5 kg of purified water, with thorough stirring. After sufficient nitrogen substitution, the temperature was increased from room temperature to 220°C over a period of approximately 1 hour while stirring. At this time, the internal pressure of the autoclave reached 18 kg / cm³ due to the natural pressure of water vapor inside the autoclave. 2 G and to prevent the pressure from reaching 18 kg / cm² 2 Once the temperature reached G or higher, the water was removed from the reaction system while heating continued. After another 2 hours, when the internal temperature reached 260°C, the heating process was stopped. The autoclave's exhaust valve was closed, and the system was cooled to room temperature over a period of approximately 8 hours. After cooling, the autoclave was opened, and about 2 kg of the polymer was removed and pulverized. The resulting pulverized polymer was placed in a 10-liter evaporator and subjected to solid-state polymerization for 10 hours at 200°C under a nitrogen stream. The resulting polymer was then extruded into strands through a bottom spinneret under nitrogen pressure. These strands were water-cooled, cut, and discharged as pellets.The pellets were then dried at 100°C for 12 hours under a nitrogen atmosphere to obtain a semi-aromatic polyamide A1-2-3 (polyamide 66 / 6I copolymer). <Herstellung der Harzzusammensetzung> [Production example 1]

[0384] A Toshiba Machine Co. Ltd. TEM58SS twin-screw extruder was used (target temperature: 280°C, screw speed: 300 rpm). A premixed blend of aliphatic polyamide A1-1, semi-aromatic polyamide A1-2-1, and titanium oxide (B-1) was fed through the top feed opening, located on the upstream part of the extruder. The melt-kneaded mixture extruded from the die head was then cooled into strands and pelletized to produce resin pellets. The mixing ratios (parts by mass) are summarized in Table 1. [Production examples 2 to 25]

[0385] Each resin composition was produced according to the same procedure as described in Production Example 1, except that the mixing ratios of components (A) to (E) were summarized as in Tables 1 and 2, and the titanium oxide B-1 was fed through the side feed opening downstream of the extruder (where the resin supplied from the top feed opening had sufficiently melted).

[0386] In production example 24, the resin composition was produced according to the same procedure as described in production example 1, with the exception that the target temperature of the twin screw extruder was changed to 250°C. [Table 1] Production example 1 2 3 4 5 6 7 Thermoplastic resin (A) Aliphatic polyamide (A1-1) Mass parts 13,0 13,0 29,0 73,0 90,0 72,0 - Semi-aromatic polyamide (A1-2-1) Mass parts 87, 0 87, 0 71,0 27,0 10,0 28,0 - Semi-aromatic polyamide (A1-2-2) Mass parts - - - - - - - Semi-aromatic polyamide (A1-2-3) Mass parts - - - - - - 100,0 Titanium oxide (B) Titanium oxide (B-1) Mass parts 1,120 1,120 1,350 1,350 1,350 1,890 1,330 Filler (C) Fiber optic (C-1) Mass parts - 11,0 33,3 33,3 33,0 100,0 33,3 Flame retardant(D) Phosphorus-based flame retardant (D-1) Mass parts - - - - - - - Dye (E) Soot (E-1) Mass parts - - - - - - - Zinc sulfide (E-2) Mass parts - - - - - - - Pigment Violet 15(E-3) Mass parts - - - - - - - In total Mass parts 101,120 112,120 134,650 134,650 134,350 201,890 134,630 Production example 8 9 10 11 12 13 14 Thermoplastic resin (A) Aliphatic polyamide (A1-1) Mass parts - 9,5 80,0 80,0 80,0 80,0 80,0 Semi-aromatic polyamide (A1-2-1) Mass parts - - 20,0 20,0 20,0 20,0 20,0 Semi-aromatic polyamide (A1-2-2) Mass parts - 90,5 - - - - - Semi-aromatic polyamide (A1-2-3) Mass parts 100,0 - - - - - - Titanium oxide (B) Titanium oxide (B-1) Mass parts 2,000 1,900 0,920 1,380 1,830 4,600 9,170 Filler (C) Fiber optic (C-1) Mass parts 100,0 100,0 46,0 46,0 46,0 46,0 46,0 Flame retardant(D) Phosphorus-based flame retardant (D-1) Mass parts - - 37,0 37,0 37,0 37,0 37,0 Dye (E) Soot (E-1) Mass parts - - - - - - - Zinc sulfide (E-2) Mass parts - - - - - - - Pigment Violet 15(E-3) Mass parts - - - - - - - In total Mass parts 202,000 201,900 183,920 184,380 184, 830 187,600 192,170 [Table 2] Production example 15 16 17 18 19 20 Thermoplastic resin (A) Aliphatic polyamide (A1-1) Mass parts 80,0 80,0 80,0 80,0 80,0 60,0 Semi-aromatic polyamide (A1-2-1) Mass parts 20,0 20,0 20,0 20,0 20,0 40,0 Semi-aromatic polyamide (A1-2-2) Mass parts - - - - - - Semi-aromatic polyamide (A1-2-3) Mass parts - - - - - - Polybutylene terephthalate (A2) Mass parts - - - - - - Titanium oxide(B) Titanium oxide (B-1) Mass parts - - 0,480 1,380 5,160 2,600 Filler (C) Fiber optic (C-1) Mass parts 46,0 46,0 46,0 46,0 46,0 130,0 Flame retardant (D) Phosphorus-based flame retardant (D-1) Mass parts 37,0 37,0 37,0 37,0 37,0 27,0 Brominated polystyrene (D-2) Mass parts - - - - - - Antimony trioxide (D-3) Mass parts - - - - - - Dye(E) Soot (E-1) Mass parts - - 0,005 0,018 - - Zinc sulfide (E-2) Mass parts - 1,835 - - - - Pigment Violet 15(E-3) Mass parts - - - 0,440 0,070 - In total Mass parts 183,000 184,835 183,485 184, 838 188,230 259,600 Production example 21 22 23 24 25 Thermoplastic resin (A) Aliphatic polyamide (A1-1) Mass parts 100,0 100,0 100,0 - - Semi-aromatic polyamide (A1-2-1) Mass parts - - - - - Semi-aromatic polyamide (A1-2-2) Mass parts - - - - - Semi-aromatic polyamide (A1-2-3) Mass parts - - - - - Polybutylene terephthalate (A2) Mass parts - - - 100,0 100,0 Titanium oxide(B) Titanium oxide (B-1) Mass parts 1,350 2,000 1,900 1,830 7,500 Filler (C) Fiber optic (C-1) Mass parts 33,3 100,0 48, 0 46,0 22,0 Flame retardant (D) Phosphorus-based flame retardant (D-1) Mass parts - - 42,0 - - Brominated polystyrene (D-2) Mass parts - - - - 15,0 Antimony trioxide (D-3) Mass parts - - - - 5,4 Dye(E) Soot (E-1) Mass parts - - - - - Zinc sulfide (E-2) Mass parts - - - - - Pigment Violet 15(E-3) Mass parts - - - - - In total Mass parts 134,650 202,000 191,900 147,830 149,900 <Physikalische Eigenschaften und Bewertung>

[0387] First, the pellets of each resin composition obtained in production examples 1 to 25 were dried in a nitrogen gas stream, reducing the moisture content in the resin composition to 500 ppm by mass or less. Subsequently, various physical properties of the pellets of each resin composition with the adjusted moisture content were measured according to the procedures described below. Furthermore, various physical properties and evaluations were carried out on the molded articles described later. [Physical property 1](glass transition temperature Tg)

[0388] The pellets of each resin composition obtained in production examples 1 to 25 were molded using an injection molding machine (ROBOSHOT S-2000i, manufactured by FANUC Corporation) with a mold temperature of either 30°C, 60°C or 80°C set under injection molding conditions of a cylinder temperature of 290°C, an injection time of 10 seconds and a cooling time of 10 seconds to produce a molded article in accordance with JIS-K7139.

[0389] The molded articles of production examples 1 to 24 were examined with a dynamic viscoelasticity analyzer (EPLEXOR 500N, manufactured by GABO) under the following conditions: (Measurement conditions) Measurement mode: Tensile stress Measurement frequency: 8 Hz Heating rate: 3°C / min Temperature range: -100°C or higher and 250°C or lower

[0390] The temperature at which tanδ reaches its maximum was used as the glass transition temperature Tg (°C), where tanδ is the ratio (E2 / E1) between the loss modulus (E2) and the storage modulus (E1). [Physical property 2](crystallization peak temperature)

[0391] The crystallization peak temperature was measured according to JIS-K7121 using a Diamond DSC (manufactured by PerkinElmer) as follows. This measurement was performed in a nitrogen atmosphere.

[0392] First, approximately 10 mg of the resin composition was heated from 40°C to 300°C at a heating rate of 20°C / min. The resin composition was then held at 300°C for 3 minutes before being cooled from 300°C to 40°C at a cooling rate of 20°C / min. After being held at 40°C for 3 minutes, the resin composition was reheated from 40°C to 300°C at a heating rate of 20°C / min. Finally, the resin composition was held at 300°C for 3 minutes before being cooled from 300°C to 40°C at a cooling rate of 20°C / min. The temperature of the crystallization peak (°C) observed during this procedure was recorded. [Physical property 3](Light absorption capacity at a wavelength of 355 nm and a thickness of 50 µm)

[0393] The pellets of each resin composition obtained in production examples 1 to 25 were formed into a flat plate sample (9 cm × 6 cm, thickness: 2 mm) using an injection molding machine (ROBOSHOT S-2000i, manufactured by FANUC Corporation) under conditions of a cooling time of 15 seconds, a screw speed of 100 rpm, a cylinder temperature of 290°C and a mold temperature of 80°C, by adjusting the injection pressure and injection speed so that the filling time is in the range of 0.5 ± 0.1 seconds.

[0394] A small piece was cut out of the shaped plate sample, and the test piece was placed in the Fig. The structure shown in Figure 1 was used. The test specimen was heated and compressed using a hot press (a two-stage heating and cooling press manufactured by Tester Sangyo Co., Ltd., capacity: 70 tons) and stretched to a thickness of 50 µm. The processing conditions for hot pressing were as follows.

[0395] Heating temperature: 300°C (production examples 1 to 23) or 270°C (production examples 24 to 25) for the upper and lower plates. Step 1: The sample was placed in the heating area and preheated for 6 minutes (in a state where the upper and lower plates are close together, without applying pressure to the sample).

[0396] Step 2: A first stage of pressing was carried out at 2 MPa (as read on the manometer of the device) and held for 3 minutes.

[0397] Step 3: A second stage of pressing was performed at 5 MPa (as read on the device's manometer) and held for 3 minutes.

[0398] Step 4: A third stage of pressing was performed at 8 MPa (as read on the device's manometer) and held for 2 minutes.

[0399] Step 5: The sample was transferred to the cooling chamber and held at a pressure of 8 MPa (as read on the device's pressure gauge). The sample was removed after the cooling water temperature had dropped to 40°C or below.

[0400] The hot-pressed sample was removed and cut into a size suitable for calibration in a spectrophotometer (V-670, JASCO Corporation, using an integrating sphere "ILN-725"). The light transmittance and light reflectance at a wavelength of 355 nm were measured using the aforementioned spectrophotometer. The light absorbance (%) was calculated by subtracting these measurements from 100%.

[0401] Fig. Figure 1 is the arrangement diagram of the sample with a thickness of 50 µm. Fig. Figure 1 shows only the layers below the sample. During the actual hot pressing, a fluoroglass disc and an aluminum plate were additionally placed over the layer in Fig. 1 sample shown attached.

[0402] The size of the cut test pieces and the placement of the underlay tape (manufactured by Misumi Corporation, thickness: 50 µm) as spacers were adjusted accordingly, so that the thickness of the sample after hot pressing was 50 µm. [Evaluation of light absorption by titanium oxide]

[0403] To investigate the effect of light absorption by titanium oxide, flat plates were produced according to the procedure described above in Production Examples 12 and 15, and samples with a thickness of 50 µm were prepared from small pieces cut from these flat plates. The light transmittance and light reflectance of these two samples were measured in the wavelength range from 300 nm to 1200 nm. The measurement results are presented in the Fig. 2 and Fig. Figure 3 shows that the transmittance and reflectance of production example 12 decreased rapidly in the wavelength range of 400 nm or shorter, indicating that titanium oxide absorbs light in this wavelength range. [Rating 1](Gloss)

[0404] The 60-degree gloss (%) of the center section of each molded item (section without printed laser markings) was measured using a gloss meter (HORIBA, IG-320) according to JIS-K7150. A higher reading indicates a better gloss. [Rating 2](Color difference)

[0405] The color value of both the laser-marked section and the adjacent unprinted (unprocessed) section of each molded item was measured using a colorimeter (SC-50µ, manufactured by Suga Test Instruments) with D65 light at a 10° angle. The brightness (L*) and hue (a*, b*) of both the laser-marked section and the adjacent unprinted (unprocessed) section were measured, and the color difference ΔE* was calculated based on the differences (ΔL*, Δa*, Δb*). A larger color difference ΔE* indicates higher clarity of the laser-marked printed markings. [Physical property 3](Ratio of the developed interface areas Sdr of the interface area of ​​a printed section produced by laser marking)

[0406] The developed interfacial area ratio Sdr of the interface of the printed section produced by laser marking of each molded article was measured with a laser microscope (measuring instrument: VK-X210, control: VK-X200, manufactured by Keyence Corporation) at an objective magnification of 20× in expert mode according to ISO 25178. [Physical property 4](Protrusion height of the printed section produced by laser marking)

[0407] The average heights of the laser-marked printed section and its surroundings in each molded item were measured using a Keyence Corporation laser microscope (measuring unit: VK-X210, controller: VK-X200) at 20x objective magnification in expert mode using the mean step height measurement method. <Herstellung des Formartikels][Beispiele 1 bis 22 und Vergleichsbeispiele 1 bis 7]

[0408] Molded parts made of flat sheets (9 cm × 6 cm, thickness: 2 mm) were produced from the pellets of each resin composition obtained in production examples 1 to 25 using an injection molding machine (ROBOSHOT S-2000i, manufactured by FANUC Corporation) under conditions of a cooling time of 15 seconds, a screw speed of 100 rpm, a cylinder temperature of 290°C (production examples 1 to 23) or 260°C (production examples 24 to 25) and a mold temperature of 80°C, by adjusting the injection pressure and injection speed so that the filling time is in the range of 0.5 ± 0.1 seconds.

[0409] The resulting flat plate molds were then laser-marked to create a 3 mm × 3 mm square imprint, thus preserving each mold. The laser marking conditions were as follows: a wavelength of 355 nm (model used: MD-U1000, manufactured by Keyence Corporation), 1064 nm (model used: MD-X2000A, manufactured by Keyence Corporation), or 10600 nm (model used: ML-Z9610, manufactured by Keyence Corporation), a scan speed of 1100 to 1700 mm / s, a power of 0.5 W, 0.75 W, or 1.0 W, a processing frequency of 40 kHz, and a processing distance of 25 µm. In Examples 21 and 22, the power was set to 1.75 W, 2.00 W, or 2.25 W, respectively.

[0410] The measurement and evaluation results of the physical properties of the individual molded articles according to the procedures described above are summarized in Tables 3 to 5. [Table 3] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Production example 1 2 3 4 5 6 7 Melting temperature during injection molding °C 80 80 80 80 80 80 80 Tg Viscoelasticity measurement °C 129 129 117 107 100 107 102 Crystallization peak temperature Cooling rate: 20 °C / min °C NoPeak NoPeak 188, 0 203,5 213,0 209,5 192,6 Transmittance (355 nm) % 63 55 38 25,4 19,4 14,1 17,2 Light reflectance (355 nm) % 10,2 9, 8 9,6 10,6 10,1 9,5 9,6 Light absorption capacity (355 nm) % 26,8 35,2 52,4 64,0 70,5 76,4 73,2 Laser marking conditions wavelength nm 355 355 355 355 355 355 355 Scan speed mm / sec 1700 1700 1700 1700 1600 1700 1700 Brightness of the unprinted area (L*) - 89,5 88, 1 87,2 86,4 85,9 87,5 86,1 Color difference: ΔE* Power output of 0.5 W - 27,2 26,0 25,5 31,1 25,6 26,2 27,0 Power output of 0.75 W - 29,5 29,2 28,2 29,4 31,5 29,7 31,6 Power output of 1.0 W - 25,2 24,7 23,5 22,3 29,3 28,8 31,7 Ratio of developed interfaces (Sdr) Power output of 0.5 W - 0,11 0,11 0,14 0,14 0,12 0,19 0,11 Power output of 0.75 W - 0,12 0,12 0,17 0,13 0,16 0,24 0,13 Power output of 1.0 W - 0,16 0,15 0,18 0,19 0,30 0,32 0,17 Lead size Power output of 0.5 W mm 0,09 0,09 1,38 0,20 1,81 2,85 0,16 Power output of 0.75 W mm 1,00 1,43 0,96 0,63 2,29 4,13 0,09 Power output of 1.0 W mm 3,89 3,06 3,62 2,51 3,75 5,01 0,68 shine 60 degrees % 87, 0 87, 0 85,5 85,0 81,7 70,2 86,0 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Production example 8 9 10 11 12 12 13 Melting temperature during injection molding °C 80 80 80 80 80 60 80 Tg Viscoelasticity measurement °C 102 124 98 98 98 98 98 Crystallization peak temperature Cooling rate: 20 °C / min °C 210,9 217 208,9 209,1 209,3 209,0 209,0 Transmittance (355 nm) % 16,3 13,2 34,2 15,9 27,4 7,3 7,3 Light reflectance (355 nm) % 9,2 11,4 10,8 10,1 9,5 8,5 8,5 Light absorption capacity (355 nm) % 74,5 75,4 55,0 74,0 63,1 84,2 84,2 wavelength nm 355 355 355 355 355 355 355 Laser marking conditions Scan speed mm / sec 1700 1700 1700 1700 1700 1700 1700 Brightness of the unprinted area (L*) - 89,1 82,3 87,2 87,1 70,1 87,0 69,8 Power output of 0.5 W - 24,0 21,5 23,4 24,5 28,2 30,1 23,0 Color difference: ΔE* Power output of 0.75 W - 28,9 22,8 26,8 25,0 25,5 28,2 24,5 Power output of 1.0 W - 29,3 22,6 25,5 23,2 24,1 26,1 23,5 Power output of 0.5 W - 0,11 0,31 0,09 0,07 0,13 0,08 0,17 ratio of the developed Power output of 0.75 W - 0,16 0,38 0,13 0,14 0,22 0,14 0,27 Interfaces (Sdr) Power output of 1.0 W - 0,27 0,45 0,22 0,21 0,31 0,20 0,33 Power output of 0.5 W mm 3,06 3,20 1,94 2,45 2,87 2,50 1,37 Lead size Power output of 0.75 W mm 2,37 4,50 2,10 2,17 3,04 2,75 1,45 Power output of 1.0 W mm 4,16 5,50 2,68 2,96 2,90 2,83 2,04 shine 60 degrees % 83,3 67,5 79,0 78,3 77,8 68,0 78,7

[0197] [Table 4] See example 1. See example 2. See example 3. Example 15 Production example 15 16 17 18 Melting temperature during injection molding °C 80 80 80 80 Tg Viscoelasticity measurement °C 98 98 98 98 Crystallization peak temperature Cooling rate: 20°C / min °C 119,1 209,6 211,3 212,5 Transmittance (355 nm) % 82,1 33,5 30,4 15,9 Light reflectance (355 nm) % 17,5 41,7 11,3 10,1 Light absorption capacity (355 nm) % 0,4 24,8 58,3 74,0 Laser marking conditions wavelength nm 355 355 355 355 Scan speed mm / sec 1700 1700 300 1700 Brightness of the unprinted area (L*) - 67,0 69,8 67,6 85,5 Color difference:ΔE* Power output of 0.5 W - Non-printable Non-printable 4,7 24,7 Power output of 0.75 W - Non-printable Non-printable 7,5 24 0 Power output of 1.0 W - Non-printable Non-printable 8, 9 21,0 Power output of 5.0 W - - - - - Ratio of developed interfaces (Sdr) Power output of 0.5 W - - - 0,42 0,16 Power output of 0.75 W - - - 0,44 0,27 Power output of 1.0 W - - - 0,62 0,38 Power output of 5.0 W - - - - - Lead size Power output of 0.5 W mm - - 6,75 2,00 Power output of 0.75 W mm - - 9,36 2,63 Power output of 1.0 W mm - - 11,78 3,34 Power output of 5.0 W mm - - - - shine 60 degrees % 76,6 77,9 77,8 78,2 Example 16 Example 17 Example 18 Example 19 Example 20 Production example 20 21 22 23 24 Melting temperature during injection molding °C 80 80 80 80 80 Tg Viscoelasticity measurement °C 113 85 87 89 79 Crystallization peak temperature Cooling rate: 20 °C / min °C 199,1 221,0 223,0 220,6 192,3 Transmittance (355 nm) % 18,7 19,8 12,8 9,5 2,5 Light reflectance (355 nm) % 9,4 12,9 10,9 11,9 10,9 Light absorption capacity (355 nm) % 71,9 67,3 76,3 78,6 86,6 Laser marking conditions wavelength nm 355 355 355 355 355 Scan speed mm / sec 1700 1700 1700 1700 1700 Brightness of the unprinted area (L*) - 90,7 87, 1 87,6 89, 0 90,5 Color difference:ΔE* Power output of 0.5 W - 23,2 19,9 20,3 19,5 24,4 Power output of 0.75 W - 25,3 23,0 20,9 21,4 25,2 Power output of 1.0 W - 25,7 23,3 19,5 19,2 27,5 Power output of 5.0 W - - - - - - Ratio of developed interfaces (Sdr) Power output of 0.5 W - 0,18 0,08 0,10 0,17 0,34 Power output of 0.75 W - 0,26 0,11 0,17 0,26 0,50 Power output of 1.0 W - 0,35 0,17 0,23 0,37 0,53 Power output of 5.0 W - - - - - - Lead size Power output of 0.5 W mm 1,12 2,34 2,35 0,08 2,52 Power output of 0.75 W mm 0,94 2,67 2,93 0,38 3,82 Power output of 1.0 W mm 0,83 2,67 3,98 1,75 4,11 Power output of 5.0 W mm - - - - - shine 60 degrees % 72,1 65,2 49,5 56,2 50,2 See example 4. See example 5. See example 6. See example. 7 Production example 12 24 12 25 Melting temperature during injection molding °C 80 80 80 80 Tg Viscoelasticity measurement °C 98 79 98 75 Crystallization peak temperature Cooling rate: 20 °C / min °C 209,3 192,3 209,3 193,1 Transmittance (355 nm) % 27,4 2,5 27,4 1,4 Light reflectance (355 nm) % 9,5 10,9 9,5 14,0 Light absorption capacity (355 nm) % 63,1 86,6 63,1 84,6 Laser marking conditions wavelength nm 1064 1064 10600 1064 Scan speed mm / sec 1700 1700 1700 1700 Brightness of the unprinted area (L*) - 70,1 90,5 70,1 81, 0 Color difference:ΔE* Power output of 0.5 W Non-printable Non-printable Non-printable Power output of 0.75 W Non-printable Non-printable Non-printable Power output of 1.0 W Non-printable Non-printable Non-printable Power output of 5.0 W - - - - 18, 0 Ratio of developed interfaces (Sdr) Power output of 0.5 W - - - - - Power output of 0.75 W - - - - - Power output of 1.0 W - - - - - Power output of 5.0 W - - - - 2,20 Lead size Power output of 0.5 W mm - - - - Power output of 0.75 W mm - - - - Power output of 1.0 W mm - - - - Power output of 5.0 W mm - - - 4,50 shine 60 degrees % 77,8 50,2 77,8 43,0 [Table 5] Example 21 Example 22 Production example 14 19 Melting temperature during injection molding °C 80 80 Tg Viscoelasticity measurement °C 98 98 Crystallization peak temperature Cooling rate: 20 °C / min °C 208,5 211,0 Transmittance (355 nm) % 0,5 1,1 Light reflectance (355 nm) % 8,5 9,1 Light absorption capacity (355 nm) % 91,0 89,8 Laser marking conditions wavelength nm 355 355 Scan speed mm / sec 1600 1100 Brightness of the unprinted area (L*) - 87,2 88,7 Color difference: ΔE* Power output of 1.75 W - 18,6 21,0 Power output of 2.00 W - 20,3 20, 9 Power output of 2.25 W - 18, 8 20,7 Ratio of developed interfaces (Sdr) Power output of 1.75 W - 0,45 0,38 Power output of 2.00 W - 0,45 0,37 Power output of 2.25 W - 0,51 0,39 Lead size Power output of 1.75 W mm 2,94 2,10 Power output of 2.00 W mm 2,73 2,65 Power output of 2.25 W mm 2,93 2,86 shine 60 degrees % 73,7 78, 1

[0411] Tables 3 to 5 showed that molded articles (Examples 1 to 22) containing titanium dioxide (B-1) with a mean particle size of 1 µm or less in an amount in the range of 0.5 parts by mass or more and 10.0 parts by mass or less per 100 parts by mass of the thermoplastic resin (A) exhibited a light reflectance at 355 nm of 17% or less when the thickness was 50 µm, and had a protrusion height of the identification section of 6.6 µm or less, and all exhibited excellent clarity in the printed section produced by laser marking.

[0412] On the other hand, in comparison examples 1 to 6, which did not meet these conditions, the clarity of the printed section produced by laser marking was poor.

[0413] The above results showed that molded articles containing titanium dioxide exhibited a light reflectance at a wavelength of 355 nm at a thickness of 50 µm and a protrusion height of the identification section within a certain numerical range, and exhibited excellent clarity of the printed section produced by laser marking. INDUSTRIAL APPLICABILITY

[0414] According to the molded article and the manufacturing process of the present embodiment, molded articles with clearly printed markings produced by laser marking can be obtained. The molded article of the present embodiment can be used in various fields, including the automotive sector, the electrical and electronics sector, the mechanical and processing sector, the office equipment sector, and the aerospace sector. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2022 / 191310 A1

[0007] JP 2013-151619 A

[0007] < / komponenten> < / formartikel>

Claims

[1] Molded articles formed by molding a resin composition containing a thermoplastic resin (A) and titanium oxide (B) with an average particle size of 1 µm or less and free of antimony-based oxides, wherein the molded article comprises: an identification section with a color tone that differs from a color tone of an surrounding section, wherein a light reflectance at a wavelength of 355 nm is 17% or less when the resin composition is formed into a shaped product with a thickness of 50 µm, and a protrusion height of the identification section is 6.6 µm or less. [2] Molded article according to claim 1, wherein the thermoplastic resin (A) comprises a polyamide-based resin (A1) and / or a polyester-based resin (A2). [3] Molded article according to claim 2, wherein the polyamide-based resin (A1) is a semi-aromatic polyamide (A1-2) containing an aromatic ring in its backbone, or an alloy of the semi-aromatic polyamide (A1-2) and an aliphatic polyamide (A1-1). [4] Molded article according to claim 3, wherein the semi-aromatic polyamide (A1-2) contains 10 mol% or more isophthalic acid units per 100 mol% of the sum of all constituent dicarboxylic acid units. [5] Molded articles according to claim 1 or 2, wherein the glass transition temperature of the resin composition is 90°C or higher. [6] Molded article according to claim 1 or 2, wherein the crystallization peak temperature of the resin composition is 240°C or less. [7] Molded article according to claim 1 or 2, wherein the resin composition further comprises a filler (C). [8] Molded article according to claim 7, wherein the resin composition contains the filler (C) in an amount of more than 0.0 parts by mass and 150.0 parts by mass or less per 100 parts by mass of the thermoplastic resin (A). [9] Molded article according to claim 7, wherein the filler (C) is at least one selected from the group consisting of glass fibers, calcium carbonate, talc, mica, wollastonite and ground fibers. [10] Molded article according to claim 1 or 2, wherein the resin composition further comprises a flame retardant (D). [11] Molded article according to claim 10, wherein the flame retardant (D) is at least one selected from the group consisting of a phosphinate salt and a diphosphinate salt. [12] Molded article according to claim 11, wherein the phosphinate salt is a compound of the following formula (I) and the diphosphinate salt is a compound of the following formula (II): in formula (I) are R 11 and R12 each independently an alkyl group with 1 or more and 6 or fewer carbon atoms or an aryl group with 6 or more and 10 or fewer carbon atoms, M n11+ is an n11-valent metal ion, M is an element of group 2 or group 15 of the periodic table, a transition element, zinc or aluminum, n11 is 2 or 3, and the respective occurrences of R 11 and R 12 They can be the same or different, and in formula (II) R 21 and R 22 each independently an alkyl group with 1 or more and 6 or fewer carbon atoms or an aryl group with 6 or more and 10 or fewer carbon atoms, Y 21 is an alkylene group with 1 or more and 10 or fewer carbon atoms or an arylene group with 6 or more and 10 or fewer carbon atoms, M' x m21+is an m21-valent metal ion, M' is an element of group 2 or group 15 of the periodic table, a transition element, zinc or aluminum, n21 is an integer of 1 or more and 3 or less, if n21 is 2 or 3, the respective occurrences of R can be 21 , R 22 and Y 21 each occurrence of M' can be the same or different, m21 is 2 or 3, x is 1 or 2, if x is 2, the occurrences of M' can each be the same or different, and n21, x and m21 are integers that satisfy the following relation formula: 2 × n21 = m21 × x. [13] Molded article according to claim 1 or 2, wherein the resin composition comprises a dye (E) and the brightness (L* value) of the molded article is 25 or more. [14] Molded article according to claim 1 or 2, wherein the resin composition contains the titanium oxide (B) in an amount of 0.5 parts by mass or more and 10.0 parts by mass or less per 100 parts by mass of the thermoplastic resin (A). [15] Molded article according to claim 1 or 2, wherein a ratio of the developed interface areas Sdr of an interface according to ISO 25178 of the identification section is 0.01 or more and 2.00 or less. [16] Molded article according to claim 1 or 2, wherein the molded article is a housing for a magnetic switch, a housing for a circuit breaker or a molded article for a connector. [17] Method for producing a laser-marked molded article, comprising: Performing laser marking on a molded article formed by molding a resin composition containing a thermoplastic resin (A), wherein the resin composition is a composition with a light reflectance at a wavelength of 355 nm of 17% or less when formed into a shaped product with a thickness of 50 µm. [18] Method for laser marking of a molded article formed by molding a resin composition containing a thermoplastic resin (A), wherein the resin composition is a composition having a light reflectance at a wavelength of 355 nm of 17% or less when formed into a molded product with a thickness of 50 µm.

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