KR100585280B1 - Resin composition for laser-marking - Google Patents

Abstract

100 parts by weight of a transparent resin composition consisting of 80 to 99 parts by weight of a rubbery four-way transparent copolymer composition and 1 to 20 parts by weight of a thermoplastic elastomer; 0.0005 to 0.5 parts by weight of a black pigment, a black dye or a mixture thereof with respect to 100 parts by weight of the transparent resin composition; And 0.0001 to 0.5 parts by weight of a blue dye, a blue pigment, or a mixture thereof, based on 100 parts by weight of the transparent resin composition. The laser marking product obtained by using the resin composition for laser marking according to the present invention is excellent in chemical resistance. In addition, when the laser marking resin composition according to the present invention is used for laser marking, a clear white marking without yellow taste can be obtained and the transparency of the product can be easily controlled.

Laser marking, rubbery quaternary transparent copolymer composition, thermoplastic elastomer, carbon black, blue dye, transparency, whiteness

Description

Resin composition for laser marking

The present invention relates to a resin composition for laser marking. More specifically, the present invention relates to a resin composition for laser marking which is excellent in clarity, easy to control transparency of a product, and excellent in chemical resistance when marking white letters or figures using a laser beam.

Conventionally, tampon printing or silk screen printing has been mainly used to display letters or symbols on the surface of plastic products. However, these operations require a very skilled and time consuming process because of the complicated steps. However, there was a limit to the display of letters or symbols in the bends. In order to prevent scratching of the first coated letters or symbols or peeling of the coated letters, an additional post-processing process is required, such as forming a transparent coating and then curing it by UV irradiation. It is almost impossible to reuse materials in post processing by UV curing. In addition, the use of solvents may cause environmental problems due to workplace pollution and the scattering of toxic substances.

Another method is the compression label method, but the disadvantage is that the letters or symbols formed by this method are not permanent.

In order to solve this problem, a method of displaying letters or symbols on the surface of a plastic product using laser light has been recently spread. This method is called laser marking method. Although the initial investment is relatively high compared to the conventional marking method, it is very easy to design letters or symbols using a computer or change the design as necessary, and the marking work is quick and very A sophisticated and uniform marking product can be obtained, and there is no need for skilled workers and almost no defective rate. In addition, since it is a non-contact type, it is easy to mark a part that cannot be marked previously, such as a curved surface, and since it does not use a solvent, there is no toxicity problem due to contamination of the working environment or use of the solvent, and it is possible to reuse the material. The marking method is rapidly expanding the area.

In the laser marking method, the marking surface made of resin absorbs the laser light and swells directly below the melting point, or the portion irradiated with the laser is evaporated to engrav or cause instantaneous chemical change on the marking surface to discolor. And bleaching (color change & bleaching). However, when white letters are marked on a black background using a laser, the color of marked characters or symbols may not be clear due to carbonization residues and oxidation of materials during laser irradiation. In addition, the use of laser-marked products often results in chemical cracks on the marked surfaces due to contact with various chemicals. For example, in the case of refrigerator parts, the chemical resistance of the product is very important because it contacts with the blowing agent during foaming or when the injection molded product is contaminated and cleaned with a solvent.

Japanese Patent Application Laid-Open No. 2001-302922 discloses a resin resin composition for laser marking comprising ferric trioxide and other colorants as black pigment in ABS resins, maleimide copolymers, and vinyl cyanide copolymers. Carbonized residues are deposited on the surface, making the marked shades not bright white or yellowish.

Japanese Patent Application Laid-Open No. 2000-212451 discloses a method of white marking a black ground using a stearyl acid metal salt, carbon black and titanium oxide after blending PMMA resin and ABS resin at a predetermined ratio. However, the marked surface does not have a satisfactory sharp whiteness.

Japanese Patent Laid-Open No. 2001-139758 discloses an ethylene- (meth) acrylic acid ester-carbon monoxide terpolymer with at least one compound selected from acrylic acid esters, aromatic vinyl compounds, vinyl cyanide compounds and maleimide compounds in the presence of a rubbery polymer. The method of laser marking using carbon black, ferric trioxide, triiron tetraoxide or titanium black as a black pigment in resin is presented. However, as a result of using the composition shown in the examples, not only the control of transparency is impossible, but also due to the use of an excessive amount of pigment, the laser light absorbing energy of the material is excessive, so that the marking rather than the swelling effect during marking is engraved. It has been found that the effect is large, the surface of the material is degraded, and carbonation residues are deposited and it is difficult to obtain clear white letters and figures. In addition, there is no mention of chemical resistance in this publication.

 The technical problem to be achieved by the present invention is to solve the above problems, it is free to control the transparency when marking white characters or figures using a laser beam, excellent whiteness of the marked white characters or figures, chemical resistance It is to provide this excellent laser marking resin composition.

The present invention to achieve the above technical problem,

Rubber mixtures grafted with aromatic vinyl compounds, (meth) acrylic acid alkyl esters, and vinyl cyan compounds in a mixture of a rubbery polymer composed of a small diameter polybutadiene rubber latex and a large diameter polybutadiene rubber latex or a rubbery polymer composed only of a large diameter polybutadiene rubber latex 4 80 to 99 parts by weight of the original transparent copolymer composition and 100 parts by weight of the transparent resin composition composed of 1 to 20 parts by weight of the thermoplastic urethane elastomer or the thermoplastic amide elastomer; 0.0005-0.5 weight part of black pigment, black dye, or mixtures thereof; And it provides a resin composition for laser marking comprising a blue dye, blue pigment or 0.0001 to 0.5 parts by weight thereof.

According to an embodiment of the present invention, the content of the small diameter polybutadiene rubber latex in the rubbery quaternary transparent copolymer is 3 to 15 parts by weight, the content of the large diameter polybutadiene rubber latex is 5 to 25 parts by weight, and aromatic vinyl The content of the compound is 15 to 30 parts by weight, the content of the (meth) acrylic acid alkyl ester is 40 to 70 parts by weight, and the content of the vinyl cyan compound may be 1 to 20 parts by weight.

In addition, when the composition according to the present invention is applied to a translucent product, the content of the black pigment or black dye is preferably 0.0005 to 0.03 parts by weight.

According to another embodiment of the present invention, the average particle diameter of the small-diameter polybutadiene rubber latex is 600-1500 mm 3, the average particle diameter of the large-diameter polybutadiene rubber latex 2600-5000 mm 3, and the gel content of both is 70-95%. And the swelling index may be 12 to 30.

According to another embodiment of the present invention, the rubber content in the rubbery four-way transparent copolymer composition is 5 to 25% by weight, the refractive index may be 1.508 to 1.528.

In addition, when the composition according to the present invention is applied to a translucent product, it is preferable that a difference between the refractive index of the thermoplastic elastomer and the refractive index of the rubbery quaternary transparent copolymer is within 0.01.

According to a preferred embodiment of the present invention, the black pigment may have a particle diameter in the range of 17 to 40 nm.

In addition, the blue dye is an anthraquinone-based, the blue pigment may be selected from the group consisting of phthalocyanine-based, cobalt blue-based, and phthalocyanine-based.

Hereinafter, the present invention will be described in more detail.

The resin composition for laser marking of the present invention is prepared by (A) grafting a (meth) acrylic acid alkyl ester compound, an aromatic vinyl compound and a vinyl cyan compound on a mixture of small and large diameter polybutadiene rubber latexes or large diameter polybutadiene rubber latexes. 80 to 99 parts by weight of a rubbery quaternary transparent copolymer having excellent impact resistance, chemical resistance and processability, and (B) 1 to 20 parts by weight of a thermoplastic urethane elastomer or thermoplastic amide elastomer having a refractive index similar to that of the rubbery transparent polymer for improving chemical resistance. 0.0005 to 0.5 parts by weight of a black pigment, a black dye or a mixture thereof, which can absorb (C) laser light, based on 100 parts by weight of the transparent resin composition [(A) + (B) = 100 parts by weight]; And (D) 0.0001 to 0.5 parts by weight of blue dyes, blue pigments or mixtures thereof to improve the whiteness of the marked letters or symbols.

 (A) Gummy 4-membered transparent copolymer

The rubbery quaternary transparent copolymer is (a) a butadiene is reacted at 55 ~ 70 ℃ by using a polymerization initiator, the average particle diameter is 600 ~ 1500Å, the gel content is 70 ~ 95%, small diameter of 12 to 30 swelling index A step of preparing a polybutadiene rubber latex, (b) to enlarge the small-diameter polybutadiene rubber latex particles particle size 2600 ~ 5000Å, gel content 70 ~ 95%, swelling index 12 ~ 30 large diameter polybutadiene rubber latex Preparing a; And (c) 3 to 15 parts by weight of the small-diameter polybutadiene rubber latex prepared in step (a), 5 to 25 parts by weight of the large-diameter polybutadiene rubber latex prepared in step (b), and 15 to 30 parts by weight of an aromatic vinyl compound. Part, 40 to 70 parts by weight of the (meth) acrylic acid alkyl ester compound, and 1 to 20 parts by weight of the vinyl cyan compound may be prepared by graft copolymerization at 65 to 80 ° C.

Particle diameter and gel content of the polybutadiene rubber latex used in the present invention has a great influence on the physical properties such as transparency and impact strength of the product, it is important to select the appropriate amount and mixing ratio. In other words, the smaller the rubber latex particle size, the better the transparency, but the impact strength and fluidity are lowered. The larger the particle size, the better the impact strength but the lower the transparency. Therefore, in order to improve transparency and impact strength at the same time, it has a small diameter and a large diameter. It is important to choose the proper mix ratio of rubber latex. In addition, if the gel content of the rubber latex is low, the monomer swells a lot in the rubber latex during graft reaction, and the apparent particle size is increased, so that the transparency decreases, but the impact strength is improved. However, the impact resistance is lowered at the time of external impact, the impact resistance is lowered.

In addition, the refractive index of the monomer mixture used in the present invention has an absolute influence on the transparency, and the refractive index is controlled by the amount of the monomer used and the mixing ratio. That is, since the refractive index of the polybutadiene is about 1.518, the refractive index of the entire grafted component should be similar to this in order to have transparency. The refractive index of each component used at this time is about 1.59 of styrene, 1.49 of methyl methacrylate, and about 1.518 of acrylonitrile.

Among the components used in the rubbery quaternary transparent copolymer, the polybutadiene rubber component mainly acts to increase the impact strength of the product, the amount of which is preferably 5 to 25 parts by weight based on the total rubbery four-way transparent copolymer. If the polybutadiene rubber component is less than 5 parts by weight, it is difficult to obtain a satisfactory impact strength, and if it exceeds 25 parts by weight, the mechanical strength tends to decrease.

The aromatic vinyl compound mainly improves the processability, and absorbs a portion of the energy that absorbs the laser light energy together with dyes, pigments and other additives that can absorb the laser light to melt and swell the irradiated portion of the laser beam. It seems to play a role. The usage-amount is adjusted so that the refractive index of an all-rubber quaternary transparent copolymer may be 1.518 in the range of 15-30 weight part with respect to an all-rubber transparent quaternary copolymer.

On the other hand, the (meth) acrylic acid alkyl ester compound absorbs a relatively small amount of laser light and is easy to swell rather than engraved, thereby enhancing the light diffusion effect of the surface to increase the whiteness of the marked letters or figures. do. In addition, the material itself during the laser irradiation is less deterioration and serves to improve the weather resistance of the final product.

In addition, the vinyl cyan compound mainly serves to enhance chemical resistance. The amount of the vinyl cyan compound is preferably 1 to 20 parts by weight based on the total amount of the vinyl cyan compound. When the amount of the vinyl cyan compound is less than 1 part by weight, the chemical resistance decreases significantly. There is a lot of space, and after laser marking, the sharpness of marked letters or figures is inferior.

The graft addition method of each component at the time of a grafting polymerization reaction can use the method of collectively administering each component, and the method of continuously administering all or part of them sequentially. In the present invention, it takes a complex form to adjust the batch and continuous administration method.

Referring to the method for producing a rubbery quaternary transparent copolymer used in the present invention in detail.

(1) Polybutadiene Rubber Latex Manufacturing Process

(a) Small Diameter Rubber Latex Manufacturing Process

100 parts by weight of 1,3-butadiene, 1 to 4 parts by weight of emulsifier, 0.1 to 0.6 parts by weight of polymerization initiator, 0.1 to 1.0 parts by weight of electrolyte, 0.1 to 0.5 parts by weight of molecular weight regulator and 90 to 130 parts by weight of distilled water by 50 to 130 The reaction is carried out at 65 ° C. for 7 to 12 hours. Subsequently, 0.05 to 1.2 parts by weight of a molecular weight modifier was further added in a batch to react at 55 to 70 ° C. for 5 to 15 hours to have an average particle diameter of 600 kPa to 1500 kPa, a gel content of 70% to 95%, and a swelling index of 12 to 30. Phosphorus small-diameter polybutadiene rubber latex is prepared.

Emulsifiers that may be used in the present invention include alkylaryl sulfonates, alkali methyl alkyl sulfates, sulfonated alkyl esters, fatty acid soaps, alkali salts of rosin acids, and the like, or may be used alone or as a mixture of two or more thereof. As a polymerization initiator, a water-soluble persulfate compound or a peroxy compound can be used, and an oxidation-reduction initiator system can also be used. Preferred water-soluble persulfate compounds are sodium persulfate compounds and potassium persulfate compounds, and fat-soluble polymerization initiators include cumene hydroperoxide, diisopropyl benzenehydroperoxide, azobisisobutyronitrile (AIBN), tertiary butyl hydroper Oxide, paramethane hydroperoxide, benzoyl peroxide, etc. can be used individually or in mixture of 2 or more types.

Electrolytes that can be used in the present invention include KCl, NaCl, KHCO ₃ , NaHCO ₃ , K ₂ CO ₃ , Na ₂ CO ₃ , KHSO ₃ , NaHSO ₃ , K ₄ P ₂ O ₇ , K ₃ PO ₄ , Na ₃ PO ₄ , K ₂ HPO ₄ , Na ₂ HPO ₄ and the like. These can be used individually or in mixture of 2 or more types. It is preferable to use mercaptans as said molecular weight regulator.

(b) Large Diameter Rubber Latex Manufacturing Process (Small Diameter Rubber Latex Fusion Process)

Particles were enlarged by gradually administering 3-4 parts by weight of an aqueous acetic acid solution to 100 parts by weight of a small diameter rubber latex having a particle diameter of 600 to 1500 mm, a gel content of 70 to 95%, and a swelling index of 12 to 30 for 1 hour. The stirring was stopped to prepare a large diameter rubber latex having a particle diameter of 2600 kPa to 5000 kPa, a gel content of 70% to 95% and a swelling index of 12 to 30. The large diameter rubber latex used to impart impact resistance can also be prepared by direct polymerization, but the direct polymerization method takes a long time to react and has a limitation in obtaining large diameter rubber latex having a high gel content. Therefore, in order to prepare a large-diameter rubber latex having a high gel content in a short time, a small-diameter rubber latex having a high gel content is first prepared, and an acidic substance is added thereto to enlarge the particles to prepare a large-diameter rubber latex. desirable.

(2) graft copolymer production process

15 to 30 parts by weight of the aromatic vinyl compound, 40 to 70 parts by weight of the (meth) acrylic acid alkyl ester compound, and vinyl to a mixture of 3 to 15 parts by weight of the small-diameter polybutadiene rubber latex prepared by the above method and 5 to 25 parts by weight of the large-diameter rubber latex Graft copolymerization is performed using 1 to 20 parts by weight of the cyan compound, 0.2 to 0.6 parts by weight of an emulsifier, 0.2 to 0.6 parts by weight of a molecular weight regulator, and 0.05 to 0.3 parts by weight of a polymerization initiator. At this time, the polymerization temperature is appropriate from 65 ℃ to 80 ℃, the polymerization time is suitable for 4 to 7 hours. Methyl methacrylate may be used as the (meth) acrylic acid alkyl ester compound in the polymerization reaction, and styrene, α-methylstyrene, o-ethylstyrene, p-ethylstyrene, vinyltoluene, etc. may be used as the aromatic vinyl compound. As a vinyl cyan compound, acrylonitrile, methacrylonitrile, (alpha)-ethyl acrylonitrile, etc. can be used. The emulsifier used in the polymerization reaction may be used alone or in combination of two or more of alkylaryl sulfonate, alkali methyl alkyl sulfate, sulfonated alkyl ester, soap of fatty acid, alkali salt of rosin acid and the like. As the molecular weight regulator, tertiary dodecyl mercaptan is mainly used. Polymerization initiators include peroxides, such as cumene hydroperoxide, diisopropylbenzenehydroperoxide, persulfate compounds, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, dextrose, sodium pyrrolate, and Oxidation-reduction catalyst systems consisting of a mixture with a reducing agent such as sodium sulfate and the like can be used. The polymerization conversion rate of the latex obtained after completion of the polymerization is 98% or more. The latex is agglomerated using an aqueous calcium chloride solution, dehydrated and dried to obtain a rubbery four-way transparent copolymer powder.

 (B) thermoplastic elastomer

The thermoplastic elastomer is used to enhance chemical resistance against solvents used in intermediate processes such as foaming processes or various solvents in which final products are contacted with a cleaning agent or final product used to remove contamination after injection. It also serves to prevent the reduction of the impact strength due to the dispersion and inorganic additives of various inorganic additives added as necessary to promote foaming during laser marking. When the resin for laser marking is manufactured using only the rubbery four-way transparent copolymer, the laser marking property is good, but chemical resistance may not be sufficient, causing chemical cracks due to various chemicals contacted in actual use after intermediate processing or assembly. Therefore, the thermoplastic elastomer is used to improve chemical resistance without compromising the transparency of the rubbery quaternary transparent copolymer.

The thermoplastic urethane elastomer or thermoplastic amide elastomer and the rubbery quaternary transparent copolymer are compatible due to the interaction of secondary polar bonds between amide groups in the thermoplastic urethane elastomer or thermoplastic amide elastomer and carboxyl groups in the rubbery quaternary transparent copolymer. great. In addition, the interaction of the alkylether properties with the styrene groups in the elastomer also improves their compatibility. Thus, the transparency of the overall blend composition is maintained due to the interaction when the refractive index of the thermoplastic urethane elastomer or thermoplastic amide elastomer is similar to the rubbery quaternary transparent copolymer.

When manufacturing the opaque laser marking products, the refractive index of the thermoplastic elastomer does not need to be considered.However, when manufacturing the product for the translucent laser marking, the refractive index difference between the thermoplastic urethane elastomer or the thermoplastic amide elastomer is different from that of the rubbery quaternary transparent copolymer. The range is preferably within 0.01. If the difference in the refractive index exceeds 0.01, there is a fear that the transparency decreases as the amount of the thermoplastic elastomer used increases.

In addition, thermoplastic urethane elastomers or thermoplastic amide elastomers are hydrophilic, so that laser-marked products do not adsorb dirt well during actual use, and also improve low temperature impact resistance and elongation.

 (C) black pigments, black dyes or mixtures thereof

Black pigments, black dyes or mixtures thereof used in the present invention absorb the laser beam energy, supply energy that the polymer molecular chain can swell, and oxidize and decolorize themselves so that white letters or white shapes appear. Do it. Therefore, the characteristics and the amount of use greatly influence the whiteness or the clarity of the letters or figures, and the kind or the amount of use also affect the transparency and the color of the base surface.

If the amount of black pigment is used too much, it is possible to mark with a small laser energy, but there are side effects such that the black pigment is left with a large amount of oxidation residue after oxidation and the presence of less oxidized black pigment on the base surface. In addition, the engraving effect is greater than the effect of swelling (foaming) due to excessive energy supply, and there is a disadvantage in that oxidation and carbonization of some resin compositions are promoted and the marked surface is not clean. On the contrary, if the amount is too small, the shortage of energy supply to the marking surface makes it difficult for the polymer chain to swell, and the energy of the laser beam required for marking increases, resulting in yellowish yellow marking or insufficient laser marking. do. In the case of manufacturing a translucent marking product, the amount of black pigment or black dye is limited in order to maintain transparency, so it is necessary to increase the laser beam energy.

(C-1) Black Pigment

The carbon black used as the black pigment preferably has a particle diameter in the range of 17 to 40 nm, and the range of the added amount is preferably 0.0005 to 0.5 parts by weight. If the particle diameter is less than 17 nm, the energy consumption is large, and if the particle diameter exceeds 40 nm, there is a fear that the tensile strength and the impact strength are lowered. The amount of black pigment used differs depending on whether the product to be laser marked is an opaque product or a transparent product.

In the case of an opaque product, it is preferable to use 0.02-0.5 weight part of black pigments with respect to 100 weight part [A + B] of transparent resin compositions, and the usage-amount changes with the color tone of a ground color. If the amount of the black pigment is less than 0.02 parts by weight, the product becomes transparent, and when titanium oxide or other inorganic filler is used to make the product opaque, there is a problem that the blackness is lowered. In general, when the background color is black or blue, the amount of carbon black is low, and when the white marking is performed on gray, titanium oxide is used, so the amount of black pigment is also increased.

In the case of transparent products, it is preferable to use 0.0005 to 0.03 parts by weight since carbon black reduces transparency. If the transparency needs to be adjusted, it may be better to mix it with black dye as needed. In general, when marking a transparent or translucent product, since the carbon black content that absorbs energy is low, the marking should be performed by increasing the power of the laser. When marking transparent or translucent products, if the carbon black content is less than 0.0005 parts by weight, the absorption of laser beam energy is too low, so the letters or symbols are not marked well, and if the power is excessively increased for marking, high energy Irradiation of the part of the composition is not good due to carbonization. If the content of the carbon black exceeds 0.03 parts by weight, the transparency is too low, there is a problem that it is difficult to make a transparent or translucent product.

(C-2) Black Dye

Black dye is mainly used to control the background color and transparency of transparent or translucent products. In the case of using carbon black alone, there is a limit in the control of the transparency, so the transparency can be controlled by using in combination with a black dye having excellent dispersibility. The amount of the black dye used is preferably in the range of 0.0001 to 0.1 parts by weight. It is possible to use in combination with dyes of other colors to change the color of other background colors.

 (D) blue dyes, blue pigments or mixtures thereof

Blue dyes, blue pigments or mixtures thereof used in the present invention are used to further improve the whiteness and sharpness of the characters or figures to be marked. Blue dyes and blue pigments enhance the whiteness of letters and figures by offsetting the yellowishness produced by surface oxidation by part of the product by the energy absorbed during laser marking. In particular, as there are less substances absorbing the laser beam energy, such as in the case of transparent or translucent products, the oxidation occurs because the intensity of the laser beam must be increased. At this time, if the blue dye or blue pigment is adjusted according to the degree of oxidation, it is possible to mark clear white letters or figures.

The blue dyes that can be used are mainly anthraquinones, and the blue pigments are mainly phthalocyanine, cobalt blue, and phthalocyanine.

In general, the amount of the blue dye or blue pigment as an auxiliary agent for improving whiteness is preferably in the range of 0.0001 to 0.5 parts by weight.

On the other hand, the resin composition for laser marking according to the present invention may further comprise titanium oxide. Titanium oxide acts to promote the foaming of the resin upon laser beam irradiation. It is also used to adjust the light transmission of the product or to improve the whiteness of the marked part during laser marking. Large particles of titanium oxide have excellent light blocking properties but are yellowish in color, so laser-marked letters or figures show slightly yellowish color, while small particles have a slightly blueish color, making the marked characters look cleaner. In terms of helping the foaming of the resin, not only titanium oxide, but also various inorganic additives such as talc may be used. In this case, if the dispersion of the inorganic additive is not dispersed, it is preferable to make and use a master batch because the marked surface is uneven. In addition, when the inorganic additive is used, the impact strength of the product may drop a lot, but since the composition according to the present invention includes a thermoplastic urethane elastomer or a thermoplastic amide elastomer, not only the impact strength may be reduced, but also the inorganic additive. It is also effective in the dispersion of.

Laser marking according to the present invention by mixing all the components, such as rubber-based four-way transparent copolymer powder, thermoplastic elastomer, black pigment, black dye, blue dye, blue pigment described above and extruded at a temperature of about 180 ℃ to about 230 ℃ The resin composition for manufacture is manufactured in the form of a master batch pellet. When producing this master batch pellet, antioxidants, heat stabilizers, lubricants, weathering enhancers, antistatic agents, antibacterial agents, and the like may be added as needed, and other colorants for color matching may also be added.

Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the scope of the present invention is not limited to the following examples.

Preliminary Example 1

1- (1): Polybutadiene Rubber Latex Manufacture

(a) Manufacture of small diameter rubber latex

110 parts by weight of distilled water, 100 parts by weight of 1,3-butadiene as monomer, 1.2 parts by weight of potassium rosin salt as emulsifier, 1.5 parts by weight of potassium oleate salt, sodium carbonate (Na ₂ CO) as electrolyte ₃ ) 0.1 parts by weight, 0.5 parts by weight of potassium hydrogen carbonate (KHCO ₃ ), 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator were added in a batch, the reaction temperature was raised to 55 ° C., and 0.3 parts by weight of potassium persulfate as an initiator. The batch was administered in batches to initiate the reaction. After the reaction for 10 hours, 0.05 parts by weight of tertiary dodecyl mercaptan was further administered and reacted at 65 ° C. for 8 hours to terminate the reaction. As a result, rubber latex having a particle diameter of 1000 mm, a gel content of 90%, and a swelling index of 18 was obtained.

(b) Manufacture of large diameter rubber latex (fusion of small diameter rubber latex)

100 parts by weight of the small-diameter rubber latex prepared above was added to the reaction tank, and 3.5 parts by weight of a 7% acetic acid aqueous solution was slowly added for 1 hour at a stirring speed of 10 rpm and a temperature of 30 ° C., and then the stirring was stopped and left for 30 minutes. Rubber latex was prepared. The particle size of the large-diameter rubber latex obtained by the fusion process was 3000 mm 3, the gel content was 90%, and the swelling index was 17.

1- (2): graft copolymer production process

100 parts by weight of distilled water, 12 parts by weight of sodium oleate emulsifier, 18.72 parts by weight of methyl methacrylate, 7.28 parts by weight of styrene, 3.33 parts by weight of acrylonitrile 0.2 parts by weight of tertiary dodecyl mercaptan, 0.048 part by weight of sodium pyrophosphate, 0.012 part by weight of dextrose, 0.001 part by weight of ferrous sulfate, and 0.04 part by weight of cumene hydroperoxide at 50 ° C. and the reaction temperature up to 73 ° C. The reaction was allowed to rise over 2 hours. And 60 parts by weight of distilled water, 0.4 parts by weight of sodium oleate, 37.44 parts by weight of methyl methacrylate, 14.56 parts by weight of styrene, 6.67 parts by weight of acrylonitrile, 0.25 parts by weight of tertiary dodecyl mercaptan, 0.048 parts by weight of sodium pyrophosphate , 0.012 parts by weight of dextrose, 0.001 parts by weight of ferrous sulfate, and 0.10 parts by weight of cumene hydroperoxide were continuously administered for 4 hours, and then heated up to 76 ° C. to mature for 1 hour and the reaction was terminated. The polymerization conversion rate was 99.5% and solid coagulation content was 0.1%. The latex was coagulated with an aqueous calcium chloride solution, washed and a powder was obtained. This is called a rubbery quaternary transparent copolymer A1.

Preliminary Example 2: Preparation of Graft Copolymer

90 parts by weight of distilled water, 0.2 parts by weight of sodium oleate emulsifier, 11.98 parts by weight of methyl methacrylate in a mixture of 8 parts by weight of small-diameter rubber latex prepared by the method of Preliminary Example 1 and 10 parts by weight of large-diameter rubber latex prepared in a nitrogen-substituted polymerization reactor , 4.52 parts by weight of styrene, 4 parts by weight of acrylonitrile, 0.2 parts by weight of tertiary dodecyl mercaptan, 0.048 part by weight of sodium pyrophosphate, 0.012 part by weight of dextrose, 0.001 part by weight of ferrous sulfate, 0.04 part of cumene hydroperoxide The weight part was dosed at 50 ° C. in a batch and the reaction temperature was raised to 73 ° C. over 2 hours. And 70 parts by weight of distilled water, 0.4 parts by weight of sodium oleate, 35.92 parts by weight of methyl methacrylate, 13.58 parts by weight of styrene, 12 parts by weight of acrylonitrile, 0.25 parts by weight of tertiary dodecyl mercaptan, 0.048 parts by weight of sodium pyrophosphate , 0.012 parts by weight of dextrose, 0.001 parts by weight of ferrous sulfate, and 0.10 parts by weight of cumene hydroperoxide were continuously administered for 4 hours, and then heated up to 76 ° C to mature for 1 hour and the reaction was terminated. The polymerization conversion rate was 99.8% and solid coagulation content was 0.12%. The latex was coagulated with an aqueous calcium chloride solution, washed and a powder was obtained. This is called rubbery quaternary transparent copolymer A2.

Preliminary Example 3

In a nitrogen-substituted polymerization reactor 25 parts by weight of large diameter rubber latex prepared by the method of Preliminary Example 1 150 parts by weight of distilled water, 0.5 parts by weight of sodium oleate emulsifier, 49.74 parts by weight of methyl methacrylate, 17.26 parts by weight of styrene, acrylonitrile 8 parts by weight, tertiary dodecyl mercaptan 0.5 part by weight, sodium pyrophosphate 0.096 part by weight, dextrose 0.024 part by weight, ferrous sulfate 0.002 part by weight, cumene hydroperoxide 0.08 part by reaction temperature 73 ° C. for 5 hours. After the reaction was administered continuously, the temperature was again raised to 80 ° C., aged for 1 hour, and the reaction was terminated. The polymerization conversion rate was 99.2% and solid coagulation content was 0.3%. The latex was coagulated with an aqueous calcium chloride solution, washed and a powder was obtained. This is called rubbery quaternary transparent copolymer A3.

Example 1

97 parts by weight of the rubbery quaternary transparent copolymer A1 prepared in Preliminary Example 1 and 3 parts by weight of a thermoplastic urethane elastomer having a refractive index of 1.518 (KOLON, K470A, refractive index of 1.518) were used as a basic resin composition. And 0.03 parts by weight of a blue dye (manufactured by Bayer, Macrolex Blue 05) were mixed in a mixer, and pellets were prepared by adjusting the cylinder temperature range of the twin screw extruder to 200 ° C. using a twin screw extruder. By injection molding using the prepared pellets, a plate-shaped specimen having a thickness of 3 mm was prepared. The prepared specimens were laser-marked by using a Nd: YAG laser marking machine (model: SY-2000) manufactured by EO Technic with a wavelength of 1064 nm, an oscillation frequency of 5 kHz, and a laser power of 3 watts.

Examples 2-6

Laser marking was performed in the same manner as in Example 1 by applying the composition described in Table 1, and the physical properties of the specimens were measured and the results are shown in Table 1.

Examples 7-12

The laser marking was carried out in the same manner as in Example 1 except that the laser power was changed to 3 to 25 watts as required by applying the composition described in Table 2, and the results of the test were measured in Table 2 Indicated.

Comparative Example 1

Laser marking was performed in the same manner as in Example 1 by applying only the rubbery transparent quaternary copolymer A1 without using the thermoplastic elastomer and applying the composition shown in Table 3 below without applying the whiteness enhancing auxiliary colorant. The physical properties of the specimens were measured and the results are shown in Table 3.

Comparative Examples 2 to 8

Laser marking was performed in the same manner as in Example 1 except that the composition of Table 3 was applied to change the laser power to 3 to 25 watts as necessary. The physical properties of the specimens were measured and the results are shown in Table 3.

The physical property evaluation of the laser marking product obtained in the said Example and the comparative example was performed by the following method.

Izod impact strength

After making a notch on a 1/8 inch specimen according to the method described in ASTM D 256, the impact strength was measured using an Izod impact tester.

transparency

Transparency was measured in the method described in ASTM D 1003.

Refractive index

The refractive index was measured according to the method described in ASTM D 542.

Marking property

Marking properties were evaluated by visual inspection.

Chemical resistance-1

The 1/8 inch tensile strength specimen was fixed by hanging on a 0.7% strain jig, and then immersed in cyclopentane for 1 minute, taken out, and left at room temperature for 4 hours. At this time, the elongation of the specimens before and after immersion of cyclopentane was measured using a universal testing machine, and the elongation retention was calculated according to Equation 1 below.

Elongation retention = (Elongation after immersion) * 100 / (Elongation before immersion)

Chemical resistance-2

The 1/8 inch tensile strength specimen was fixed on a 0.7% strain jig, and then the surface of the specimen was covered with toilet paper and hexane was dropped 5 times using a pipette. At this time, the elongation of the specimen before and after dropping of hexane was measured using a universal testing machine, and the elongation retention was calculated according to Equation 2 below.

Elongation retention = (elongation after loading) * 100 / (elongation before loading).

division Example One 2 3 4 5 6 Gum quaternary copolymer A1 97 97 97 98 A2 95 A3 97 Thermoplastic elastomer B1 3 5 3 B2 3 2 B3 3 Black Pigment & Dye Carbon black 0.05 0.05 0.05 0.05 0.05 0.05 Black Dye Whiteness enhancement auxiliary colorant Blue Dye 0.03 0.03 0.03 0.03 0.03 Blue Pigment 0.02 Evaluation item Impact strength 10 15 25 10 11 11 transparency opacity opacity opacity opacity opacity opacity Chemical resistance-1 93% 97% 100% 96% 100% 90% Chemical resistance-2 67% 75% 96% 72% 100% 65% Ground color black black black black black black Marking color White White White White White White Marking property Good Good Good Good Good Good Laser Power (Watt) 3 3 3 3 3 3

Note) A1: rubber content 12% by weight, refractive index 1.517;

A2: rubber content 18% by weight, refractive index 1.518;

A3: rubber content 25% by weight, refractive index 1.518,

B1: thermoplastic urethane elastomer (Kolon Oil Co., Ltd., K470A) refractive index 1.518;

B2: thermoplastic urethane elastomer (Kolon Oil Co., Ltd., K285PCAT), refractive index 1.525;

B3: thermoplastic amide elastomer (Japanese Sanyo Chemical Co., Pelestat NC6321), refractive index 1.51;

Carbon Black: Pigment Black 07, from Nippi Korea,

Black Dye: Mitsubishi, Diaresin Black B,

Blue dyes: Bayer, Macrolex Blue 3R,

Blue pigment: Holiday, Ultramarine Blue 05.

division Example 7 8 9 10 11 12 Gum quaternary copolymer A1 97 92 97 97 97 A2 95 A3 Thermoplastic elastomer B1 3 8 5 3 B2 3 B3 3 Black Pigment & Dye Carbon black 0.015 0.01 0.008 0.04 0.05 0.02 Black Dye 0.015 0.01 Whiteness enhancement auxiliary colorant Blue Dye 0.003 0.05 0.06 0.015 Blue Pigment 0.02 0.02 0.03 Titanium oxide 0.3 0.5 0.1 Evaluation item Impact strength 10 12 15 10 11 11 transparency Translucent Translucent Translucent opacity opacity opacity Chemical resistance-1 95% 100% 92% 100% 94% 96% Chemical resistance-2 70% 98% 87% 100% 94% 92% Ground color black black Black Blue Hall Hall Dark gray Marking color White White White White White White Marking property Good Good Good Good Good Good Laser Power (Watt) 25 25 20 7 3 7

division Comparative example One 2 3 4 5 6 7 8 polymer A1 100 70 30 90 ABS 25 25 30 30 SAN 25 30 70 70 PMMA 50 75 70 10 Black Pigment & Dye Carbon black 0.05 0.15 0.5 0.5 0.5 0.5 Triiron tetraoxide 0.3 0.5 Whiteness enhancement auxiliary colorant Titanium oxide 0.3 0.2 Evaluation item Impact strength 10 14 7 3 12 17 19 9 transparency opacity opacity opacity opacity opacity opacity opacity opacity Chemical resistance-1 23% 75% 23% 16% 65% 84% 75% 25% Chemical resistance-2 59% 77% 22% 18% 53% 82% 80% 25% Ground color black black black black black black black black Marking color White White White White White White White White Marking property Good Bad Bad Blank Bad Bad Bad Bad Laser Power (Watt) 3 25 3 7 3 3 3 3

Note) ABS: Butadiene / styrene / acrylonitrile (weight ratio) = 50/36/15,

SAN: styrene / acrylonitrile (weight ratio) = 75/25,

PMMA: LG Chemicals, IF-850.

As shown in Table 1, Examples 1 to 6 had good elongation retention after application of cyclopentane and hexane, and as a result of visually observing the marking state, a marking product having good whiteness was obtained on an opaque black background.

In Examples 7 to 9, all of the products were translucent products, and elongation retention was good after applying cyclopentane and hexane, and marking products having good whiteness were obtained on the translucent black background.

In Examples 10 to 12, all the letters and graphics marked as opaque products in which the background color of the product was changed were good white. Elongation retention after application of cyclopentane and hexane was also good.

In Comparative Example 1, the background color of the product was opaque black, and all marked letters or symbols were good white. However, the elongation retention was significantly lowered after the application of cyclopentane and hexane.

In Comparative Examples 2 to 8, the background color of the product was opaque black, and the marked letters or symbols were carbonized and deposited, and the surface was dirty, and yellowish white was added, or the elongation retention after cyclopentane and hexane was also significantly decreased. .

As described above, the laser marking product obtained by using the resin composition for laser marking according to the present invention has excellent chemical resistance. In addition, when the laser marking resin composition according to the present invention is used for laser marking, a clear white marking without yellow taste can be obtained and the transparency of the product can be easily controlled.

Claims (8)

Aromatic vinyl compound, alkyl (meth) acrylate 100 parts by weight of a transparent resin composition composed of 80 to 99 parts by weight of an ester and a vinyl cyan compound-grafted rubbery quaternary transparent copolymer composition, and 1 to 20 parts by weight of a thermoplastic urethane elastomer or a thermoplastic amide elastomer; 0.0005 to 0.5 parts by weight of a black pigment, a black dye or a mixture thereof based on 100 parts by weight of the transparent resin composition; And A resin composition for laser marking, comprising 0.0001 to 0.5 parts by weight of a blue dye, a blue pigment or a mixture thereof, based on 100 parts by weight of the transparent resin composition. The content of the small-diameter polybutadiene rubber latex in the rubbery quaternary transparent copolymer is 3 to 15 parts by weight, the content of the large-diameter polybutadiene rubber latex is 5 to 25 parts by weight, and the content of the aromatic vinyl compound. Is 15 to 30 parts by weight, the content of the (meth) acrylic acid alkyl ester is 40 to 70 parts by weight, and the content of the vinyl cyan compound is 1 to 20 parts by weight. The resin composition for laser marking according to claim 1, wherein when applied to a translucent product, the content of the black pigment or the black dye is 0.0005 to 0.03 parts by weight. The resin composition for laser marking according to claim 1, wherein the gel content of the small-diameter polybutadiene rubber latex and the large-diameter polybutadiene rubber latex is 70 to 95% and the swelling index is 12 to 30. The resin composition for laser marking according to claim 1, wherein the rubber content in the rubbery quaternary transparent copolymer composition is 5 to 25% by weight and the refractive index is 1.508 to 1.528. The resin composition for laser marking according to claim 1, wherein when applied to a semitransparent product, a difference between the refractive index of the thermoplastic elastomer and the refractive index of the rubbery quaternary transparent copolymer is within 0.01. The resin composition for laser marking according to claim 1, wherein the black pigment has a particle size in the range of 17 to 40 nm. The resin composition for laser marking according to claim 1, wherein the blue dye is an anthraquinone series, and the blue pigment is selected from the group consisting of phthalocyanine series, cobalt blue series, and phthalocyanine series.