KR101137442B1 - Polybutylene terephtalate resin composition for Laser White marking - Google Patents

Abstract

The present invention relates to a polybutylene terephthalate resin composition for white marking, and more particularly, to a white marking poly comprising polybutylene terephthalate resin, glass fiber, black pigment masterbatch, conductive carbon black masterbatch and dispersant. It relates to a butylene terephthalate resin composition. Since the polybutylene terephthalate resin composition of the present invention shows excellent whiteness and sharpness when marking white without reducing mechanical properties, the polybutylene terephthalate resin composition may be usefully applied to the manufacture of a personal computer keyboard.

Description

Polybutylene terephtalate resin composition for Laser White marking

The present invention relates to a polybutylene terephthalate resin composition capable of laser white marking, and the polybutylene terephthalate resin composition of the present invention is excellent in mechanical strength and sharpness and whiteness when laser white marking, thus producing a keyboard of a personal computer. This can be usefully applied.

Laser marking is the use of a laser to write on a plastic or to display a specific number. This technology can be adjusted to various shapes using a graphic computer program and can simplify manufacturing lines. Lasers available for marking plastics include CO ₂ lasers and Nd: YAG lasers. CO ₂ lasers can be laser marked by thermochemical reactions, melting and vaporization at wavelengths up to 10,000 mm / sec at 10,600 nm. In the case of Nd: YAG laser, laser marking is possible by carbonization, sublimation, discoloration, bubble generation, etc. at a wavelength of up to 2,000 mm / sec at 1,064 nm.

Laser marking includes black marking for marking black or dark colors on the surface of moldings of high brightness and white marking for marking white on the surfaces of black or dark moldings. In the case of white marking, a dark background is generally made by adding carbon black to a plastic resin, and when the laser beam is irradiated to the manufactured plastic resin, carbon black on the surface of the molded product is decomposed to generate volatile components. The heat absorbed from the laser beam creates bubbles on the surface, which scatters the light, leaving a brightly colored white image.

In order to obtain laser white marking with excellent whiteness and sharpness, it is very important to increase the contrast with the background color. To this end, Korean Patent Nos. 10-0495449, 10-0521703, 10-0576314 and the like propose resins containing titanium oxide, silicate compounds, high molecular weight polyethylene waxes, etc. In addition to severely deteriorating the mechanical strength of the reinforcement products, the technique is limited to acrylic resins, and when applied to polybutylene terephthalate resins, sufficient contrast was not obtained. In addition, Japanese Patent Application Laid-Open No. 63-811177 discloses a method of compounding inorganic compounds such as titanium black, cordierite and mica in JP-A-4-267191, and aluminum hydroxide in JP-A-5-25317. There is a problem that the whiteness improvement effect does not reach the degree of commercialization.

Recently, a technology for improving the marking characteristics by applying a laser absorption additive has been proposed and commercialized in Korea Patent Registration No. 10-0697977, etc., but since the additive is expensive, the expensive laser absorption additive is used in a large amount to obtain desired characteristics. There is a difficulty. In addition, most of the commercially available laser absorption additives use mica (MICA) as a base material, and thus, in the case of a product including glass fiber, mica breaks the glass fiber during extrusion, thereby lowering the mechanical strength of the final product.

Accordingly, the present inventors have tried to solve the above problems, using a black pigment masterbatch, a conductive carbon black masterbatch and a dispersant under conditions of Nd: YAG laser mainly used for industrial use, expensive to cause mechanical properties reduction The present invention has been completed to realize that a fiberglass-reinforced polybutylene terephthalate resin composition capable of clear white marking can be prepared without using a laser absorption additive.

Accordingly, an object of the present invention is to provide a polybutylene terephthalate resin composition for laser white marking having excellent sharpness and whiteness without reducing mechanical properties.

The present invention is a black pigment masterbatch 0.5 to 3 parts by weight, conductive carbon black masterbatch 0.5 to 3 parts by weight based on 100 parts by weight of a resin composition composed of 60 to 80% by weight of polybutylene terephthalate resin and 20 to 40% by weight of glass fiber. It is characterized by a polybutylene terephthalate resin composition for laser white marking comprising a portion and 0.4 to 3 parts by weight of a dispersant.

The polybutylene terephthalate resin composition according to the present invention includes a black pigment masterbatch, a conductive carbon black masterbatch, and a dispersant, so that laser white marking with excellent sharpness and whiteness is possible while maintaining mechanical strength according to glass fiber content. It can be usefully applied to the manufacture of keyboards and the like.

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

The present invention includes a polybutylene terephthalate resin having excellent clarity and whiteness in laser white marking, including a glass pigment masterbatch, a conductive carbon black masterbatch, and a dispersant, which contain glass fibers to enhance mechanical properties and do not break glass fibers. It relates to a composition.

The polybutylene terephthalate resin is prepared by a known polymerization method such as melt polymerization, interfacial polymerization or solution polymerization from aromatic dicarboxylic acid or ester derivatives thereof and 1,4-butanediol or ester derivatives thereof. It may be used, but is preferably a product produced by the melt polymerization method. As aromatic dicarboxylic acid, it is preferable to use terephthalic acid in which isophthalic acid is mixed at 50 wt% or less. If the weight ratio of terephthalic acid is less than 50%, not only the heat resistance of the entire resin is lowered, but also there may be a problem that the crystallization is slow and the injection molding cycle is long. In the polybutylene terephthalate resin of this invention, raw materials other than the raw material mentioned above can also be used further as a copolymerization component in the range which does not impair the characteristic of invention according to the objective. Examples thereof include ortho phthalic acid, 2,6-naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, succinic acid, adipic acid, sebacic acid, dodecanoic acid, dimer acid, or ester derivatives thereof, and the like. Although not limited to the above, constituents capable of copolymerization may be used, and one or more kinds may be used simultaneously.

The polybutylene terephthalate resin is an ortho chloro phenol (o-Chloro Phenol) solution, the intrinsic viscosity measured at 25 ℃ is preferably in the range of 0.35 ~ 1.60 dl / g, more preferably 0.50 ~ 1.25 dl / It should be in the range of g. If the intrinsic viscosity is too low, the mechanical properties may be lowered. If the intrinsic viscosity is too low, the fluidity may be lowered, resulting in uneven surfaces during injection molding, thereby preventing a uniform appearance required for laser marking.

Moreover, according to the objective, other crystalline resin other than polybutylene terephthalate resin can be used within the range which does not impair a characteristic. Specific examples of usable crystalline resins include polyester resins, polyethylene terephthalate resins, polypropylene terephthalate resins, polyamide resins, and polyphenylene sulfides. (Polyphenylene sulfide) resins, polyphenylene oxide resins, polyacetal resins, thermoplastic polyester elastomers and the like.

The polybutylene terephthalate resin is preferably 60 to 80% by weight when the mixture with the glass fiber is 100% by weight, and when it is less than 60% by weight, the visibility is lowered due to the decrease in the laser marking property due to the glass fiber surface projection. There may be a problem, if it exceeds 80% by weight there may be a problem that mechanical properties such as heat deformation temperature is lowered.

The glass fiber is used as the inorganic filler having a particle length of 3 to 5 mm, the diameter of 10 to 14 ㎛ level. When the particle length is smaller than 3 mm, the rigidity and impact resistance properties may be lowered, and when the particle length is larger than 5 mm, workability may be deteriorated. In addition, if the diameter is less than 10 ㎛ mechanical properties are increased but agglomeration may occur, the workability may be lowered, if larger than 14 ㎛ may have a problem that the impact resistance is lowered. The amount of glass fiber is preferably 20 to 40% by weight when the mixture with the polybutylene terephthalate resin is 100% by weight. If it is less than 20% by weight, the heat resistance and stiffness may be lowered. The weight increase and the workability may be lowered.

In addition, the glass fiber may be coated with an epoxy silane or the like in order to increase the bonding strength with the polybutylene terephthalate as a substrate, and the type of silane used in this case is within the range of not deteriorating the physical properties of the substrate. You can use it in various ways.

As the black pigment used in the black pigment masterbatch, various carbon blacks may be used regardless of a raw material or a manufacturing method, and for example, furnace black, channel black, acetylene black, and ketjen black may be used. The preferred average particle diameter of the carbon black is 10 to 50 nm, and the preferred oil absorption is 50 to 100 cc / 100 g. If the average particle diameter of the carbon black is too small or the oil absorption is too large, the particles are too fine to easily handle. On the contrary, if the average particle diameter is too large or the oil absorption is too small, the dispersibility is lowered. Appearance color development tends to be reduced. Black pigment used in the present invention is prepared and added to the master batch to improve handling stability, dispersibility, color development. The amount of the prepared black pigment masterbatch is 0.5 to 3 parts by weight, preferably 0.5 to 1 part by weight based on 100 parts by weight of the resin composition composed of polybutylene terephthalate resin and glass fiber. When the amount of the masterbatch is too high, gas may be generated on the appearance of the molded article, thereby decreasing the sharpness and contrast when laser white marking, and when the amount of the masterbatch is too small, the blackness of the resin composition may be reduced.

The laser sensitive component used in the present invention uses a conductive carbon black to prepare a masterbatch. The conductive carbon black has the advantage that the laser marking property is improved compared to the general carbon black because carbon black particles are agglomerate and are present as large agglomerates. The conductive carbon black used in the present invention preferably has an average particle diameter of 10 to 30 nm and an oil absorption of 100 to 200 cc / 100 g. If the average particle diameter of the conductive carbon black is too small or the oil absorption is too large, the particles are too fine to easily handle. On the contrary, when the average particle diameter is too large or the oil absorption is too low, the color development and sharpness of the laser marking part are very low. Is likely to be degraded. The amount of the conductive carbon black masterbatch prepared is preferably 0.5 to 3 parts by weight based on 100 parts by weight of the resin composition composed of polybutylene terephthalate resin and glass fiber. If the amount is too small, the color development may be degraded during laser marking, and the visibility of the marking portion may be deteriorated, so that smooth marking may not be realized. If the amount is too large, contrast at the boundary of marking is hardly obtained. The conductive carbon black masterbatch has a low blackness, so synergistic effects occur when used with a black pigment masterbatch rather than alone.

The dispersant has a function of improving the dispersibility of the laser sensitive component (conductive carbon black) and increasing the surface smoothness to provide a surface favorable for marking. Such dispersants may include saponified montan ester waxes derived from montanic acid or high molecular weight polyolefin waxes, and when used in combination with two types of waxes, the surface surface smoothness and the dispersion of glass fibers are improved. It is preferable to use together because it gives a favorable surface for marking. The amount of the dispersant is 0.4 to 3 parts by weight based on 100 parts by weight of the resin composition consisting of polybutylene terephthalate resin and glass fiber, if the amount of the dispersant is too small, it is difficult to obtain a clear factor because of low dispersibility improvement effect, If the amount of the dispersant is too large, problems such as adhesion of the dispersant to the mold by evaporation and sublimation may occur.

In addition to the essential components may be added to the barium sulfate (Barium Sulfate) powder to the inorganic particles to improve the sharpness of the marking character. The barium sulfate powder preferably has an average particle diameter of 0.5 to 2 µm, more preferably 0.75 to 1.25 µm. If the average particle diameter is less than 0.5 μm, there may be a problem of uniform dispersion during compounding due to the increase of surface tension, and if it exceeds 2 μm, carbon black particles are concealed by the barium sulfate particles, thereby irradiating laser light. ), The foaming effect is reduced, so there may be a problem that the whiteness of the marking character falls. The whiteness of the powder itself satisfies 98 or more by CIE L * value (brightness value), and preferably contains 96% or more of barium sulfate (BaSO ₄ ). When the brightness value of the barium sulfate powder is low, the whiteness of the marking character may be lowered. The oil absorption of the barium sulfate powder is preferably 10 to 20 cc / 100 g. If the oil absorption exceeds the above range, the whiteness of the marking portion and the contrast of the interface may be reduced. When the barium sulfate powder is added, the amount used is 0.01 to 1 parts by weight, more preferably 0.05 to 0.5 parts by weight, and more preferably 0.05 to 0.3, based on 100 parts by weight of the resin composition composed of polybutylene terephthalate resin and glass fiber. It is good to use in parts by weight. If the amount is too small, the sharpness of the marking character may fall, and if used too much, the impact strength of the molded body may be lowered.

To the resin composition of the present invention, conventional additives such as antioxidants, stabilizers, ultraviolet absorbers, colorants, flame retardants, flame retardant aids, impact modifiers, and the like may be further added within a range that does not impair the effects of the invention.

The method for producing the polybutylene telephthalate resin composition of the present invention is not particularly limited, and after mixing the components used in the present invention in a super mixer, a single screw, twin screw extruder, Banbury mixer, Kneader, etc. It can advance in melt kneading machine etc.

Since the polybutylene terephthalate resin composition according to the present invention is capable of laser white marking with excellent sharpness and whiteness without deteriorating mechanical strength, it can be usefully applied to the manufacture of personal computer keyboards and various molded articles.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

[Example]

Preparation Example 1 Preparation of Black Pigment Masterbatch

70 parts by weight of polybutylene terephthalate resin (SUPET EB800, Hyundai EPI), 30 parts by weight of carbon black (HIBLACK 600L, Evonik Degussa) with an oil absorption of 72 cc / 100 g, an average particle diameter of 16 nm and saponified montan ester 1 part by weight of wax (LICOWAX OP, Clariant, Inc.) was kneaded and kneaded with a kneader to prepare a masterbatch using a twin screw extruder.

Preparation Examples 2 to 5: Preparation of Conductive Carbon Black Masterbatch

Conductive carbon black (HIBLACK 30B, Evonik Degussa Co., Ltd.) (Manufacturing Example 2) having the same degree of oil absorption as 110 cc / 100 g and an average particle diameter of 23 nm, respectively, Conductive carbon black with induction of 130 cc / 100 g and an average particle diameter of 19 nm (HIBLACK 41Y, Evonik Degussa) (Production Example 3), conductive carbon having an oil absorption of 150 cc / 100 g and an average particle diameter of 25 nm Black (HIBLACK 40B2, Evonik Degussa Co., Ltd.) (Production Example 4), oil absorption of 170 cc / 100 g and an average particle diameter of 20 nm, substituted with conductive carbon black (VULCAN XC72, CABOT Co., Ltd.) (Production Example 5) Masterbatch was prepared.

Examples 1-4

Polybutylene terephthalate resin, glass fiber (diameter 10 μm, length 3 mm), black pigment masterbatch, conductive carbon black masterbatch, dispersant and antioxidant in a super mixer, 40 mm in diameter, 2 L / D 52 A polybutylene terephthalate resin composition was prepared using a screw extruder at a temperature of 200 to 400 rpm at a temperature of 230 to 260 ° C. The content of the constituent materials is shown in Table 1 below.

Example 5

It carried out similarly to Example 2, but added 0.2 weight part of barium sulfate powders (average particle diameter 1 micrometer, oil absorption 14 cc / 100g) further.

Comparative Examples 1 to 5

A polybutylene terephthalate resin composition was prepared using a black pigment masterbatch or a conductive carbon black masterbatch alone.

Comparative Examples 6 to 7

Polybutylene terephthalate using a mica-based laser sensitive additive (Comparative Example 6) and a solvent black laser sensitive additive (Comparative Example 7) without using a black pigment masterbatch and a conductive carbon black masterbatch, respectively. A resin composition was prepared.

Comparative Example 8

A polybutylene terephthalate resin composition was prepared in the same manner as in Example 2, without adding a dispersant.

division Example (parts by weight) Comparative example (parts by weight) One 2 3 4 5 One 2 3 4 5 6 7 8 A-1 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 A-2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 55.2 B 30 30 30 30 30 30 30 30 30 30 30 30 30 C 0.5 0.5 0.5 0.5 0.5 One - - - - - - 0.5 D-1 One - - - - - One - - - - - - D-2 - One - - One - - One - - - - One D-3 - - One - - - - - One - - - - D-4 - - - One - - - - - One - - - E-1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 - E-2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 - F - - - - 0.2 - - - - - - - - G-1 - - - - - - - - - - One - - G-2 - - - - - - - - - - - One - H 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 A-1: Polybutylene Terephthalate Resin [SUPET EB900, Hyundai EP]
A-2: Polybutylene Terephthalate Resin [SUPET EB800, Hyundai EP]
B: glass fiber [G / F 952, Owens Corning Korea]
C: Black pigment masterbatch prepared in Preparation Example 1
D-1: conductive carbon black masterbatch prepared in Preparation Example 2
D-2: Conductive Carbon Black Masterbatch Prepared in Preparation Example 3
D-3: Conductive Carbon Black Masterbatch Prepared in Preparation Example 4
D-4: Conductive Carbon Black Masterbatch Prepared in Preparation Example 5
E-1: Saponified Montan Ester Wax [LICOWAX OP, Clariant]
E-2: High molecular weight polyethylene oxide wax [PED191, Clariant]
F: Barium Sulfate Powder [HD80, Solvay Corporation]
G-1: Mica based laser sensitive additive [LASERFLAIR 835, Merck]
G-2: Solvent Black Laser Sensitive Additive [VALIFAST 3820, Orient]
H: Antioxidant [IRGANOX, Ciba company]

Physical property test

One) The tensile strength

Tensile strength of the specimens was measured using a Tinious Olsen UTM instrument according to ASTM D 638.

2) Izod  Impact strength

The impact strength of the notched specimen at 23 ° C. was measured using a Tinious Olsen Model 235 instrument according to ASTM D 256.

3) marking  Exterior

Using the prepared resin composition, a hollow cylindrical molded article having a diameter of 100 mm and a height of 100 mm was used to evaluate laser marking characteristics on flat specimens of 100 mm width, 100 mm thickness, 2 mm thickness, 3 mm and curved surfaces. Nd: YAG lasers with 1,064 nm wavelength were white-marked at 46-90% power and pulse frequency of 1-30 kHz using a laser marking apparatus, and the appearance was visually evaluated. The evaluation was evaluated in the order of ◎ (very good)> O (excellent)> Δ (good)> X (bad).

division Example Comparative example One 2 3 4 5 One 2 3 4 5 6 7 8 The tensile strength
(Kgf / cm ² ) 1355 1354 1355 1352 1357 1350 1345 1351 1348 1347 1150 1310 1350 Impact strength
(Kgf cm / cm) 9 9 9 9 9 9 9 9 9 9 7 8.5 9 back
color
Degree 3mm specimen O O O O ◎ X △ △ △ △ O X △ 2 mm specimen O ◎ O O ◎ X △ △ △ △ O X △ Molded article O O O O ◎ X △ △ △ △ O X △ line
persons
Degree 3mm specimen O O O O ◎ X △ △ △ △ O X △ 2 mm specimen O ◎ O O ◎ X △ △ △ △ O X △ Molded article O O O O ◎ X △ △ △ △ O X △

As shown in Comparative Examples 1 to 5 of Table 2, when using the black pigment master batch or the conductive carbon black master batch alone, it can be seen that there is a problem that the whiteness and the sharpness due to laser marking are lowered. In Comparative Example 6 using a mica-based laser sensitive additive, there is a problem in that tensile strength and impact strength are decreased due to breakage of the glass fiber, and in Comparative Example 7 using a solvent black laser sensitive additive, the mechanical strength is good. In the fiber-reinforced polybutylene terephthalate composition, it can be seen that the whiteness and sharpness are greatly reduced during laser marking. In addition, in Comparative Example 8, in which the dispersant was not added, it was confirmed that the whiteness and sharpness of the laser marking were greatly reduced due to the decrease in surface smoothness.

As a result, when the conductive carbon black masterbatch is used instead of the mica-based laser susceptibility additive, and the black pigment masterbatch and the dispersant are used to prevent the mechanical strength of the composition, as in the present invention, the whiteness and the clarity in the laser white marking are It was confirmed that an excellent polybutylene terephthalate resin composition can be obtained and can be usefully applied to the production of personal computer keyboards and various molded articles.

Claims (7)

100 parts by weight of a resin composition composed of 60 to 80% by weight of polybutylene terephthalate resin and 20 to 40% by weight of glass fiber,
0.5-3 parts by weight of a black pigment masterbatch made of carbon black having an oil absorption of 50 to 100 cc / 100 g;
0.5 to 3 parts by weight of a conductive carbon black masterbatch made of conductive carbon black having an oil absorption of 100 to 200 cc / 100 g; And
0.4 to 3 parts by weight of dispersant;
Polybutylene terephthalate resin composition for laser white marking comprising a.
The polybutylene terephthalate resin composition for laser white marking according to claim 1, wherein the black pigment masterbatch is made of carbon black having an average particle diameter of 10 to 50 nm.
The polybutylene terephthalate resin composition for laser white marking according to claim 1, wherein the conductive carbon black masterbatch is made of conductive carbon black having an average particle diameter of 10 to 30 nm.
The polybutylene terephthalate resin composition for laser white marking according to claim 1, wherein the dispersant is saponified montan ester wax, high molecular weight oxidized polyolefin wax, or a mixture thereof.
The polybutylene terephthalate resin composition for laser white marking according to any one of claims 1 to 4, further comprising barium sulfate powder.
The polybutylene tere for laser white marking according to claim 5, wherein the barium sulfate powder is added in an amount of 0.01 to 1 parts by weight based on 100 parts by weight of the resin composition composed of the polybutylene terephthalate resin and the glass fiber. Phthalate resin composition.
6. The polybutylene terephthalate resin composition for laser white marking according to claim 5, wherein the barium sulfate powder has an average particle diameter of 0.5 to 2 µm and an oil absorption of 10 to 20 cc / 100 g.