JP2015083621A - Polycarbonate resin compositions excellent in laser marking property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polycarbonate resin compositions excellent in laser marking property containing, with respect to 100 pts.wt. of a polycarbonate resin (A), 0.003 to 3 pts.wt. of a specific bismuth-based metal oxide (B) and 0.01 to 0.2 pts.wt. of a phosphorus-based antioxidant (C).SOLUTION: The polycarbonate resin compositions excellent in laser marking property is extremely useful because it can be applied to clear black marking with high visibility of degree that marks such as characters, symbols and images can be clearly recognized on visual inspection by laser irradiation while maintaining properties such as transparency and heat stability that the polycarbonate resin originally has. These resin compositions can be suitably applied to a sheet having clearer characters, symbols, images and the like by laser for improving security of mainly credit cards, bank cards, transportation cards, authorization cards or the like.

Description

  The present invention relates to a polycarbonate resin composition excellent in laser marking properties. More specifically, laser marking that enables marking with good contrast to the extent that marks such as letters and symbols can be clearly recognized by laser light irradiation while maintaining the transparency, heat resistance, thermal stability, etc. inherent to polycarbonate resin. The present invention relates to a polycarbonate resin composition having excellent properties.

  In recent years, as a method of writing characters, barcodes, images, etc. on the surface of a plastic card such as a non-contact IC card, a method of marking by irradiating a laser beam instead of embossing or printing has been adopted. It has become. For example, by writing information on a card using a YAG laser or the like, it is possible to prevent the written information from being lost due to wear or aging. As a result, in many industries now, conventional ink systems are moving to laser marking systems.

For laser marking, a CO2 laser, an Nd: YAG laser, or the like is used. In order to enable fine printing, an Nd: YAG laser is mainly used.
However, when laser marking is applied to a resin molding material with an Nd: YAG laser, almost all major resin molding materials do not provide marking with sufficient quality in terms of visibility and definition, and few resins cannot be printed at all. Absent.
Therefore, an additive capable of improving the visibility of laser marking is required for main resin molding materials, and several laser marking agents have been proposed so far.

  For example, Patent Document 1 describes that particles of a mixed oxide of tin and antimony having a particle size of 10 to 70 nm are added to a molding material as an additive for laser marking.

  Patent Document 2 discloses an additive for laser marking using a pigment obtained by coating tin oxide doped with antimony, arsenic, bismuth, copper, gallium, germanium or their oxide on a flaky substrate such as mica flakes or SiO2 flakes. Thermoplastics and the like included therein are disclosed.

  Patent Document 3 discloses that when laser marking is applied to a resin molded product in which a composite oxide composed of copper and molybdenum is added to a resin, a color change with high blackness is found. However, when these composite oxides are added to the resin, there is a problem that the resin turns yellow.

  On the other hand, a polyvinyl chloride resin (PVC resin) composition has been used as a conventional material for a card to which a laser mark is applied from the viewpoints of printability, embossability, laminate suitability, and the like. However, when the PVC resin composition is irradiated with a laser, chlorine gas may be generated from the heating part, and there are many complicated problems such as special separation and collection required at the time of disposal. For this reason, polycarbonate resin having high heat resistance has been attracting attention as a suitable resin material that can replace PVC resin.

Special table 2007-512215 gazette Japanese National Patent Publication No. 10-500149 JP 2005-75674 A

  The present invention improves the above-mentioned problems and can clearly recognize marks such as letters and symbols by laser irradiation while maintaining the properties such as transparency, heat resistance, and heat stability inherent in the polycarbonate composition. Disclosed is a polycarbonate resin composition excellent in laser marking properties that can be marked with a good contrast.

  As a result of intensive studies in view of the above problems, the present inventors have surprisingly added transparency to the polycarbonate resin by adding a specific bismuth-based metal oxide and a phosphorus-based antioxidant together. Has been found to be excellent in the thermal stability (hue), and the visibility of the contrast of marks such as letters and symbols can be improved, and the present invention has been completed.

That is, the present invention relates to 0.003 to 3 parts by weight of a bismuth-based metal oxide (B) represented by the following general formula 1 and a phosphorus-based antioxidant (C) with respect to 100 parts by weight of the polycarbonate resin (A). The present invention provides a polycarbonate resin composition excellent in laser marking properties, characterized by containing 0.01 to 0.2 parts by weight.
General formula 1
Bi _(1-x) M _x O _y
(In General Formula 1, M is at least one metal selected from gadolinium and neodymium, and x and y are values having a relationship of 0.001 <x <0.5 and 1 <y <2.5, respectively. .)

  The polycarbonate resin composition excellent in laser marking properties of the present invention is clearly visible with marks such as letters, symbols and images by laser irradiation while maintaining the properties such as transparency and thermal stability inherent to the polycarbonate resin. A clear black marking with high contrast and high visibility is recognizable, which is extremely useful. These resin compositions are mainly used for various cards such as credit cards, bank cards, transportation cards, government employee IDs, passports, employee ID cards, medical insurance cards, resident card cards, driver's licenses, vehicle registration cards, etc. In order to improve security, it can be suitably applied as a resin sheet with clearer characters, symbols, images, etc. by laser.

Hereinafter, embodiments of the present invention will be described in detail.
In the present invention, “marking” means forming letters, designs, symbols, etc., and the laser marking according to the present invention usually means that a laser beam irradiated part by a YAG laser or the like is a laser non-irradiated part. On the other hand, it is a marking that becomes visible when it has a black or blackish color tone with relatively low brightness.

  The polycarbonate resin (A) used in the present invention is obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxyaryl compound and a carbonate such as diphenyl carbonate are reacted. A typical example of the polymer is a linear polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A).

  Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like. However, it is preferred from the environmental viewpoint to use a dihydroxydiaryl compound not substituted with halogen.

  These can be used alone or in admixture of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

  The viscosity average molecular weight of the polycarbonate resin (A) is not particularly limited, but is usually in the range of 10,000 to 100,000, more preferably 15,000 to 40,000, and still more preferably 17,000 to 28,000 in terms of moldability and strength.

  Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like.

  These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be used in combination.

Examples of the bismuth (Bi) -based metal oxide particles (B) used in the present invention include those composed of a compound represented by the following general formula 1.
General formula 1
Bi _(1-x) M _x O _y
(Wherein M is at least one metal selected from gadolinium and neodymium, and x and y are values having a relationship of 0.001 <x <0.5 and 1 <y <2.5, respectively). expressed.

Moreover, since the bismuth-type metal oxide used for this invention maintains the dispersibility to resin, the form of particle | grains is preferable, and a finer marking is enabled, so that the particle diameter is small.
The average particle diameter D50 is preferably 10 μm or less, and more preferably 1 μm or less.
The bismuth metal oxide used in the present invention is preferably a compound produced from bismuth trioxide and gadolinium trioxide as a raw material, or a compound produced from bismuth trioxide and neodymium trioxide as a raw material.
This bismuth-based metal oxide can be easily obtained as a commercial product, and examples of the commercial product include 42-920A manufactured by Toago Material Technology Co., Ltd.

  As a compounding quantity of a bismuth type metal oxide (B), it is 0.003-3 weight part per 100 weight part of polycarbonate resin (A). If the blending amount is less than 0.003 parts by weight, it is difficult to obtain a sufficient laser marking effect. On the other hand, when the amount exceeds 3 parts by weight, the appearance of a sheet or molded article made of the resin composition obtained is impaired, which is not preferable. More preferably, it is 0.005 to 2 parts by weight.

Examples of the phosphorus-based antioxidant (C) used in the present invention include compounds composed of compounds represented by the following general formulas 2 and 3.
General formula 2

（一般式２において、Ｒ５、Ｒ６は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を、ａ、ｂは整数０〜３を示す。）。
一般式３

(In General Formula 2, R5 and R6 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.).
General formula 3

（一般式３において、Ｒ７は炭素数１〜２０のアルキル基、またはアルキル基で置換されてもよいアリール基を、ｃは０〜３の整数を示す。）

(In General Formula 3, R7 represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and c represents an integer of 0 to 3)

As a compound of the general formula 2, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane Adeka stab PEP-36 manufactured by Adeka Corporation is listed as commercially available.
As the compound of the general formula 3, Sumitizer P-168 manufactured by Sumitomo Chemical Co., Ltd. may be mentioned as commercially available.

  The compounding quantity of phosphorus antioxidant (C) is 0.01-0.2 weight part per 100 weight part of polycarbonate resin (A). If the blending amount is less than 0.01 parts by weight, a sufficient antioxidant effect cannot be obtained, resulting in poor thermal stability (hue), thereby reducing the contrast between the fabric part and the mark part such as letters, which is not preferable. . On the other hand, if it exceeds 0.2 parts by weight, the thermal stability becomes insufficient at the time of retention during the molding process, and it is not preferable because it turns yellow. More preferably, it is 0.05 to 0.10 parts by weight.

  Various known additives, polymer materials, and the like can be added to the polycarbonate resin composition excellent in laser marking properties of the present invention as desired. For example, in order to suppress discoloration of the resin molded product when exposed to light for a long period of time, a hindered amine-based light-resistant stabilizer is used, and further, in order to obtain a vivid color tone, a benzoxazole-based fluorescent whitening agent and These may be added in combination.

  When flame retardancy is required, various known flame retardants, for example, brominated flame retardants such as tetrabromobisphenol A oligomers, monophosphate esters such as triphenyl phosphate and tricresyl phosphate, bisphenol A diesters, etc. In order to further improve the flame retardancy, phosphorous flame retardants such as phosphate-type condensed phosphates such as phosphate, resorcin diphosphate, tetraxylenyl resorcin diphosphate, ammonium polyphosphate and red phosphorus, various silicone flame retardants And metal salts of aromatic sulfonic acid and perfluoroalkanesulfonic acid, preferably 4-methyl-N- (4-methylphenyl) sulfonyl-benzenesulfonamide potassium salt, diphenylsulfone- 3- potassium sulfonate, Potassium phenyl sulfonic -3-3'- disulfonic acid, sodium para-toluene sulfonic acid, also organic metal salts such as potassium perfluorobutane sulfonate and the like may be added. Among these flame retardants, phosphorus-based flame retardants can be suitably used because they can improve not only flame retardancy but also fluidity.

  Furthermore, known additives other than those mentioned above, for example, lubricants [paraffin wax, n-butyl stearate, synthetic beeswax, natural beeswax, glycerin monoester, montanic acid wax, polyethylene wax, pentaerythritol tetrastearate, etc.], coloring agents [For example, titanium oxide, carbon black, dye], filler [calcium carbonate, clay, silica, glass fiber, glass sphere, glass flake, carbon fiber, talc, mica, various whiskers, etc.], fluidity improver, spreading Agents [epoxidized soybean oil, liquid paraffin, etc.], and other thermoplastic resins and various impact resistance improvers (polybutadiene, polyacrylates, ethylene / propylene rubbers, rubbers such as methacrylates, styrene, Graft polymerization of compounds such as acrylonitrile Beam reinforced resins.) Can be added as required.

  There are no restrictions on the embodiment and order of the polycarbonate resin used in the present invention. For example, polycarbonate resin (A), bismuth-based metal oxide (B), phosphorus-based antioxidant (C) are weighed in an arbitrary blending amount and mixed together using a tumbler, riboblender, high-speed mixer, etc. A method of melt-kneading and pelletizing using a normal single-screw extruder or twin-screw extruder, or individually or partially weighing individual components, and feeding them into a extruder from a plurality of supply devices, A method of melt mixing, further blending polycarbonate resin component (A), bismuth metal oxide (B) and phosphorus antioxidant (C) in high concentration, once melt mixed and pelletized, Then, the master batch and the polycarbonate resin can be mixed in a desired ratio. Then, when these components are melt-mixed, arbitrary conditions such as the position to be fed into the extruder, the extrusion temperature, the screw rotation speed, and the supply amount can be selected and pelletized.

  By simply irradiating a desired position with a laser beam on a sheet molded product or the like molded from the resin composition for laser marking according to the present invention, clear black marking is easily performed. In order to perform marking of a desired shape, for example, a method of scanning the surface of an object with a laser beam as an appropriate spot, a method of irradiating the surface of the object with a laser beam of a desired shape by masking the laser beam, etc. Is mentioned. The type of laser used is not particularly limited, and any of carbon dioxide laser, ruby laser, semiconductor laser, argon laser, excimer laser, YAG laser, and the like are possible. A YAG laser is particularly preferable. The YAG laser has a wavelength of 1.06 μm, and its energy is hardly absorbed by the resin itself, so that the resin does not easily burn or vaporize. Particularly preferred is a scanning Nd: YAG laser.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

The details of the used blending components are as follows.
Polycarbonate resin (A):
Polycarbonate resin synthesized from bisphenol A and phosgene (viscosity average molecular weight: 23000)
(Sumika Stylon Polycarbonate Caliber 200-3, hereinafter abbreviated as PC)
Bismuth metal oxide (B):
Metal oxide particles synthesized from bismuth trioxide and neodymium trioxide (Bi-Nd, particle size 1.0 μm)
(42-920A manufactured by Toago Material Technology Co., Ltd., hereinafter abbreviated as RM)
Phosphorous antioxidant (C):
3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane (phosphorus-based oxidation manufactured by ADEKA) Inhibitor PEP-36, hereinafter abbreviated as AO)

  After drying the pellets of various resin compositions obtained based on the blending components and blending ratios shown in Tables 1 and 2 at 120 ° C. for 4 hours, the pellets were melted with an injection molding machine (J100E2-P manufactured by Nippon Steel Tsuna Co., Ltd.). A color chip (flat plate test piece) for evaluation (size: 60 mm × 60 mm × 2 mm) was prepared under the condition of a temperature of 300 ° C.

Hereinafter, various evaluation items and measurement methods in the present invention will be described.
1. Color development evaluation (black marking property)
The obtained color chip was irradiated with a YAG laser (Laserfront SL475K manufactured by OMRON Corporation), and sample characters were laser-marked under the conditions of a feed speed of 1200 mm / second, an input current of 13.0 A, and a Q-sw frequency of 5 kHz. The case where the black sample character can be clearly recognized visually is judged as good (◎), the case where it can be recognized visually (○), and the case where the visual recognition property is poor (×).

2. Hue Evaluation The hue of the obtained color chip was measured using a spectrophotometer CMS35SP manufactured by Murakami Color Research Laboratory under the conditions of a D65 light source and a viewing angle of 10 degrees. The case where the yellowness after marking was 7.0 or less was regarded as good hue. The results are shown in Tables 1 and 2.

3. Print sharpness (contrast)
The print sharpness (contrast) of the marking portion of the obtained color chip was determined. Judgment criteria are as follows.
The clearness of the print is judged visually. The contrast between the color of the fabric part and the marking character color is very good “◎”, the contrast between the color of the fabric part and the marking character color is “good”, the color of the fabric part and the marking character The color contrast was evaluated as poor “×”.
The results are shown in Tables 1 and 2.

As shown in Examples 1 to 4, those satisfying the constituent requirements of the present invention satisfied the required performance.
On the other hand, as shown in Comparative Examples 1 to 4, those that do not satisfy the constituent requirements of the present invention have the following drawbacks.
Comparative Example 1 was a case where the blending amount of the antioxidant (AO) was less than the specified amount and was inferior in hue.
Comparative Example 2 was a case where the blending amount of the antioxidant (AO) was larger than the specified amount, and the hue was inferior.
Comparative Example 3 was a case where the blending amount of the laser marking agent (RM) was less than the specified amount and was inferior in character color development.
Comparative Example 4 was a case where the blending amount of the laser marking agent (RM) was larger than the specified amount, and the print clarity was inferior.

Claims (5)

0.003 to 3 parts by weight of a bismuth metal oxide (B) represented by the following general formula 1 and a phosphorus antioxidant (C) 0.01 to 0 with respect to 100 parts by weight of the polycarbonate resin (A) Polycarbonate resin composition excellent in laser marking property, characterized by containing 2 parts by weight General formula 1
Bi _(1-x) M _x O _y
(In General Formula 1, M is at least one metal selected from gadolinium and neodymium, and x and y are values having a relationship of 0.001 <x <0.5 and 1 <y <2.5, respectively. .)   2. The resin composition according to claim 1, wherein an amount of the bismuth-based metal oxide (B) is 0.005 to 2 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A).   2. The resin composition according to claim 1, wherein the bismuth-based metal oxide (B) has an average particle size of 10 μm or less. The resin composition according to claim 1, wherein the phosphorus-based antioxidant (C) is a compound represented by the following general formula 2.
General formula 2

(In General Formula 2, R1 and R2 represent an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and a and b represent integers 0 to 3.)   2. The resin composition according to claim 1, wherein the amount of the phosphorus antioxidant (C) is 0.03 to 0.15 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A). object.