KR20030054169A - Laser Markable Thermoplastic Resin Compositions - Google Patents

Abstract

PURPOSE: A thermoplastic resin composition is provided, which can be used to make a white-marking material with excellent definition and whiteness even at a low energy intensity of laser. CONSTITUTION: The thermoplastic resin composition comprises 100 parts by weight of an acryl-based resin; 0.01-5 parts by weight of a black dye or pigment; 0.01-10 parts by weight of a silicate-based compound; and optionally 20 parts by weight or less of a white inorganic filler. Preferably the acryl-based resin is a homopolymer or copolymer of at least one monomer selected from an acrylic acid or methacrylic acid, and alkyl acrylate or alkyl methacrylate, or a copolymer of an acryl-based monomer and at least one kind of vinyl ester-based monomer.

Description

Laser Markable Thermoplastic Resin Compositions

Field of invention

The present invention relates to a thermoplastic resin composition capable of laser marking. More specifically, the present invention is capable of white-marking which is excellent in clarity and whiteness by a laser, and particularly in thermoplastic resin compositions which are capable of white-marking even in a state of low energy intensity of the laser beam, and also of excellent quality. It is about.

Background of the Invention

In general, various printing is performed on the surface of the plastic material, and many methods are known from pad printing or impregnation printing to laser marking. Although paint methods are the most common, it is well known that these methods have many problems in terms of process cost, pollution, and durability. On the other hand, laser marking is a cheaper, more effective, and more durable method than painting. Japanese Laid-Open Patent Publication No. 56-45926 proposes a resin capable of laser marking by incorporating a filling material whose color disappears by a laser beam.

An example of laser marking is a keyboard of a personal computer (PC). The main method of keyboard printing is pad printing (for ABS resin) or impregnation printing (for PBT resin). However, due to environmental problems and high cost, including recycling, printing on ABS resins using Nd: YAG lasers or other lasers is replacing the above method.

In general, black or dark marking (hereinafter black-marking) on the surface of moldings of light gray, cream or bright color is effective, but white on the surface of black or dark resin moldings is effective. White-marking is not effective enough.

According to Japanese Patent Application Laid-Open No. 2-47314, when a laser is irradiated on the surface of a molded article of acrylic resin, bubbles are generated while swelling and white-marking at that part. Japanese Patent Application Laid-Open Nos. 63-81117, 4-267191 and 5-25317 disclose methods for incorporating titanium black, mica and aluminum hydroxide into a resin, respectively, to white-mark the surface of the resin molding. However, these methods do not have enough clarity or quality of the marked part.

In order to solve the above problems, the present inventors have come to develop a thermoplastic resin composition capable of white-marking with excellent clarity and whiteness by combining a special resin composition with dyes / pigments and silicate compounds.

An object of the present invention is to provide a white-marking thermoplastic resin composition excellent in clarity and whiteness by a laser.

Another object of the present invention is to provide a thermoplastic resin composition capable of white-marking and excellent in quality even in a low energy intensity of a laser beam.

Both the above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

The thermoplastic resin composition capable of laser marking of the present invention comprises 100 parts by weight of an acrylic resin (A), 0.01 to 5 parts by weight of a black dye or pigment (B) and 0.01 to 10 parts by weight of the silicate compound (C). In addition, the white inorganic filler (D) may be further included in an amount of 20 parts by weight or less.

In the thermoplastic resin composition of the present invention, a resin other than the acrylic resin (A) may be added as the base resin, and when another resin is added, the acrylic monomer ratio is suitably 1 to 100% by weight, more preferably 10 to 100. Weight percent. In addition, general additives such as dyes, pigments, flame retardants, fillers, stabilizers, lubricants, antibacterial agents, and mold release agents other than the compatibilizer, the black dye or the pigment (B) or the white inorganic filler (D) may be included.

Detailed Description of the Invention

The (A) acrylic resin, (B) black dye or pigment, (C) silicate compound, and (D) white inorganic filler which are each component of the thermoplastic resin composition which can enable clear laser marking of this invention are demonstrated in detail below.

(A) acrylic resin

The acrylic resin (A) used in the production of the resin composition of the present invention includes a homopolymer or copolymer in which at least one monomer selected from acrylic acid or methacrylic acid, acrylic acid alkyl ester or methacrylic acid alkyl ester is used. The role of the acrylic resin (A) is to form bubbles by the laser beam so that white-marking appears on the surface of the resin composition.

Acrylic acid alkyl esters or methacrylic acid alkyl esters are esters obtained from methacrylic acid or acrylic acid and monohydryl alcohols containing 1 to 8 carbon atoms. Specific examples thereof include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid propyl ester, acrylic acid butyl ester, acrylic acid hexyl ester, acrylic acid 2-ethylhexyl ester, or a corresponding methacrylic acid ester. Acid methyl esters are most preferred.

In the acrylic resin (A) used in the present invention, one or more comonomers other than the acrylic monomer may be added to form a copolymer. The conditions of a comonomer should just be what can be copolymerized with said acrylic monomer. Typical examples thereof include vinyl acetate and vinyl ester monomers such as styrene monomers. Specific examples include styrene, alkyl styrene, halogen styrene, maleic anhydride, acrylonitrile, methacrylonitrile, N-alkylmaleimide, N-cycloalkylmaleimide, N-arylmaleimide and the like.

In the case of the monomer, it is not copolymerized with the acrylic monomer, but may be used by blending with the acrylic resin after forming a polymer or copolymer.

Rubber may be added to acrylic resin (A). Examples include polybutadiene, butadiene-styrene copolymer, polyisoprene, butadiene-acrylonitrile copolymer, isobutylene-isoprene copolymer, ethylene-propylene rubber, acrylic rubber, urethane rubber, silicone rubber and the like. These rubber components may be copolymerized to an acrylic resin, but may be used after being copolymerized with a styrene or acrylonitrile resin and then blended with an acrylic resin.

1-100 weight% is suitable for the component ratio of the acrylic monomer in acrylic resin (A), More preferably, it is 10-100 weight%. If the component of the acrylic monomer is too small, the foam (foam) is not properly formed during laser irradiation, the quality of the white-marking is deteriorated.

(B) black dyes or pigments

The black dye or pigment used in the production of the resin composition of the present invention is an organic or inorganic dye or pigment of black or dark color. These black dyes / pigments convert the absorbed laser beam into thermal energy to generate foaming of the resin.

Types of black dyes / pigments include carbon black, titanium black and black iron oxide, and may be used alone or in combination. The particle diameter of these black dyes / pigments is suitably 10 nm-3 micrometers. There are also black dyes in which three dyes of yellow, red and blue are blended, and these can also be used alone or in combination with the inorganic black.

The content of the black dye / pigment is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 2 parts by weight.

(C) Silicate Compounds

The silicate compounds used in the production of the resin composition of the present invention are inorganic or organosilane compounds such as SiO ₂ or clay minerals containing silicates. These silicate compounds serve to form a film upon laser irradiation to enhance the whiteness and durability of the foam.

Among the types of silicate compounds, minerals include SiO ₂ , smokite clay minerals such as montmorillonite, hectorite, and saponite. 10 nm-10 micrometers of these particle diameters are suitable.

These are used alone or in mixtures, and their amount is suitably 0.01 to 10 parts by weight, more preferably 0.1 to 3 parts by weight. If the content is too small, the marking performance is lowered. If the content is too high, the physical properties of the resin composition are lowered.

Among the kinds of silicate compounds, organic compounds include silane compounds, and examples thereof include dialkyl silanes, alkyl-aryl-silanes, and diaryl silanes. Dialkyl silanes are preferable.

When the organosilane compound is mixed with the inorganic silicate, the effect is obvious, and the content of the organosilane compound is preferably 0.01 to 1 part by weight based on 100 parts by weight of the acrylic resin (A).

(D) white inorganic filler

The white inorganic filler used in the manufacture of the resin composition of the present invention is not particularly limited. Examples thereof include calcium carbonate, titanium oxide, zinc oxide, zinc sulfide, and the like, and these white inorganic fillers are believed to help the role of black dyes / pigments by enhancing the hiding power of the resin and scattering the laser beam.

White inorganic filler is an optional component in the present invention, it is preferably used in an amount of 20 parts by weight or less, more preferably in an amount of 0.1 to 5 parts by weight.

The weight ratio of the black dye / pigment (B) and the white inorganic filler (D) is preferably 0.01 to 50, more preferably 0.1 to 5.

Resin other than the acrylic resin (A) may be added to the resin composition of the present invention as a base resin. Specific examples thereof include polyamide, polyester, polyphenylene sulfide, polyphenylene oxide, polyacetal, polyimide, poly (ether ether Ketone (poly (ether ether ketone)), polycarbonate (polycarbonate), epoxy resin (epoxy resin), polyurethane (polyurethane), unsaturated polyester (unsaturated polyester) and the like. When another resin is added, the ratio of the acrylic monomer is suitably 1 to 100% by weight, more preferably 10 to 100% by weight.

In addition, general additives such as dyes, pigments, flame retardants, fillers, stabilizers, lubricants, antibacterial agents, and mold release agents other than the compatibilizer, the black dye or the pigment (B) or the white inorganic filler (D) may be included.

The resin composition may be prepared by various moldings after mixing by a known mixing method using an extruder, a kneader, a mixer, or the like. By irradiating the surface of this molding with a laser, white-marking with excellent sharpness can be obtained. Types of laser beams include YAG lasers, CO ₂ lasers, Ar lasers, excimer lasers, and the like, of which YAG lasers are mainly used.

The resin composition of the present invention is much superior to the sharpness and whiteness of the laser-marked portion, compared to the prior art, there is an advantage that can be vivid white-marking at low laser beam intensity.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

The specifications of (A) acrylic resin, (B) black dye / pigment, (C) silicate compound and (D) white inorganic filler used in the following Examples and Comparative Examples are as follows.

(A) Acrylic resin: A methyl methacrylate-styrene copolymer having a methyl methacrylate monomer content of 50% by weight and a weight average molecular weight (Mw) of 100,000 was used.

(B) Black dye / pigment: Carbon black was used.

(C) a silicate-based compound was used for SiO _2.

(D) White inorganic filler: Titanium oxide was used.

In addition to the above components, polystyrene having a weight average molecular weight (Mw) of 100,000 was used, Irganox 1076 (Ciba) as an antioxidant, and ethylene bis-stearamid as a lubricant.

Example 1-4 and Comparative Example 1-2

Using the above components, the same resin composition as that shown in Example 1-4 and Comparative Example 1-2 of Table 1 was prepared. Pellets were prepared using the biaxial extruder as a component of Table 1, and a specimen for laser marking was prepared using an injection machine. The laser used to compare the white-marking performance was an Nd: YAG laser with a wavelength of 1064 nm.

White-marking performance was determined as follows, and the results are shown in Table 1.

Marking clarity and whiteness Very bad Bad usually good Very good Rating One 2 3 4 5

Example Comparative Example One 2 3 4 One 2 Component (parts by weight) (A) acrylic resin 100 100 100 70 100 - (B) black dyes / pigments 0.5 0.5 0.5 0.5 0.5 0.5 (C) Silicate Compounds One 2 3 3 - 3 (D) white inorganic filler 3 - - 3 3 3 polystyrene - - - 30 - 100 Antioxidant 0.1 0.1 0.1 0.1 0.1 0.1 Lubricant 0.5 0.5 0.5 0.5 0.5 0.5 Marking grade 4 5 5 5 2 One

From the results in Table 1, it can be seen that the resin composition of Example 1-4 using the silicate compound (C) showed excellent white-marking performance. Comparative Example 1 is a case where the silicate-based compound (C) is not used, which is white-marked but its quality is not satisfactory. In addition, Comparative Example 2 shows that the white-marking performance is very poor when the acrylic resin (A) is not used.

The present invention is composed of acrylic resin, black dye / pigment, silicate-based compound and optionally white inorganic filler, and is capable of white-marking with excellent clarity and whiteness by laser, especially in the state of low energy intensity of laser beam. Marking is possible and has the effect of providing a thermoplastic resin composition with excellent quality.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (8)

A thermoplastic resin composition capable of laser marking, comprising (A) 100 parts by weight of acrylic resin, (B) 0.01-5 parts by weight of black dye or pigment, and 0.01-10 parts by weight of (C) silicate compound. The laser marking of claim 1, wherein the acrylic resin (A) is a homopolymer or copolymer using at least one monomer selected from acrylic acid or methacrylic acid, acrylic acid alkyl ester or methacrylic acid alkyl ester. Thermoplastic resin composition. The thermoplastic resin composition of claim 1, wherein the acrylic resin (A) is a copolymer in which an acrylic monomer and a vinyl ester monomer such as at least one vinyl acetate or styrene monomer are used. The method of claim 1, wherein the polybutadiene, butadiene-styrene copolymer, polyisoprene, butadiene-acrylonitrile copolymer, isobutylene-isoprene air Rubber selected from the group consisting of isobutylene-isoprene copolymer, ethylene-propylene rubber, acrylic rubber, urethane rubber or silicone rubber is the acrylic resin ( A thermoplastic resin composition capable of laser marking, which is copolymerized with A) or copolymerized with styrene or acrylonitrile resin and then blended with acrylic resin. The method of claim 1, wherein the silicate-based compound (C) is a SiO ₂ or a montmorillonite, hectorite, mineral, such as saponite of the smectite type of clay minerals and / or di-alkyl silane, alkyl-aryl-silane or Dia A thermoplastic resin composition capable of laser marking, which is an organosilane compound such as reel silane. The laser marking-enabled thermoplastic resin according to claim 5, wherein when the inorganic material and the organosilane compound are mixed and used, the content of the organosilane compound is 0.01 to 1 part by weight based on 100 parts by weight of the acrylic resin (A). Composition. According to claim 1, In addition to the acrylic resin (A) polyamide (polyamide), polyester (polyester), polyphenylene sulfide (polyphenylene sulfide), polyphenylene oxide (polyphenylene oxide), polyacetal (polyacetal), Group consisting of polyimide, poly (ether ether ketone), polycarbonate, epoxy resin, polyurethane or unsaturated polyester The laser marking capable thermoplastic resin composition further comprises another resin selected from. The thermoplastic resin composition according to any one of claims 1 to 7, further comprising a white inorganic filler (D) in an amount of 20 parts by weight or less.