JP2005213346A - Surface-modified polycarbonate molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polycarbonate resin molding that causes no crack and has excellent adhesion and appearance of coating film even if the surface of a molding is decorated by a treatment agent containing an organic solvent in coating or printing. <P>SOLUTION: The polycarbonate resin molding is surface treated so that the amount of chemiluminescence at 300-650 nm wavelength in a nitrogen atmosphere at 140°C for 30 minutes reaches 30,000-1,200,000 count based on 1 cm<SP>2</SP>measurement surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polycarbonate molded article formed by extrusion molding, injection molding, injection compression molding, or the like and having a surface modified. More specifically, the present invention relates to a polycarbonate molded product having excellent appearance without cracking the molded product even if the molded product is decorated with a treatment agent containing an organic solvent such as coating or printing.

  Polycarbonate has excellent mechanical properties, electrical properties, heat resistance, transparency and the like, and is used in a wide range of fields such as automobiles, OA equipment, electricity / electronics, architecture, and household goods. When polycarbonate is used as a meter cover or nameplate for automobiles, OA equipment, electrical / electronic equipment, cameras, etc., the surface of the molded product is often decorated by printing, painting, or the like. Since polycarbonate has low chemical resistance, cracks may occur due to the organic solvent used during printing and painting, and adhesion failure of the coating film may occur. In order to eliminate these defective phenomena, for example, a method is disclosed in which the printing surface of a polycarbonate sheet is irradiated with ultraviolet rays having a wavelength of 200 to 400 nm to prevent the occurrence of cracks (see Patent Document 1). This document does not specifically describe the amount of ultraviolet rays to be irradiated and the modification level of the printing surface. According to the method of Patent Document 1, the generation of cracks is completely achieved even if the printing surface is irradiated with ultraviolet rays. It was not possible to prevent.

  Also disclosed is a pretreatment method for plastic coating, characterized in that the plastic is washed with water and then the surface of the plastic is irradiated with a synthetic quartz high-pressure mercury lamp (see Patent Document 2). This document describes that a synthetic quartz high-pressure mercury lamp has a high spectral intensity of a short wavelength of 200 nm or less, and that a short-wavelength ultraviolet light of 200 nm or less breaks the bond of an organic compound. Nevertheless, the preferable irradiation time and irradiation energy of ultraviolet rays are not defined, and there is no quantitative description of what level the plastic surface is to be modified.

  Furthermore, a polycarbonate film and a method for producing the same are disclosed in which a die line pattern does not occur when the polycarbonate film is exposed to a solvent gas of an aliphatic ketone by the method described in the text (see Patent Document 3). ). However, the objects described in this document are limited to films, the occurrence of cracks when exposed to aliphatic ketone solvent gas, and the adhesion of the coating film after printing or painting using organic solvents. There is no mention about. Furthermore, since the polycarbonate resin film is irradiated with near ultraviolet rays, most of the irradiation wavelength is smaller than the binding energy, the degree of modification is considered to be small, and cracks in the polycarbonate resin film due to organic solvents used during printing and painting It was not possible to completely prevent the occurrence of adhesion and the poor adhesion of the coating film.

JP 63-12463 A Japanese Patent Laid-Open No. 5-68934 JP 2000-327808 A

  An object of the present invention is to provide a polycarbonate molded product in which cracks and poor adhesion of a coating film are prevented from occurring in a polycarbonate resin molded product using an organic solvent used in printing and painting.

The present invention has been made to solve the above-described problems. That is, for the molded products modified to various levels by various methods, the results of evaluating the surface modification state by various methods were compared with the results of crack resistance and appearance evaluation after surface decoration. As a result, it was found that there was a great relationship between the amount of chemiluminescence on the surface of the molded product and the crack resistance and appearance after surface decoration. In other words, even if the surface is decorated with a treatment agent containing an organic solvent such as painting or printing, the molded product does not crack, and the molded product with excellent appearance is a 140 ° C. nitrogen atmosphere for 30 minutes. And the amount of chemiluminescence measured at a wavelength of 300 nm to 650 nm is found to be a polycarbonate resin molded product whose surface has been modified so that the measurement surface has a count of 30,000 to 1,200,000 per cm ² , The present invention has been completed.

In the present invention, the polycarbonate resin surface-treated so that the amount of chemiluminescence having a wavelength of 300 nm to 650 nm measured for 30 minutes in a nitrogen atmosphere at 140 ° C. is 30,000 counts to 1,200,000 counts per 1 cm ^2. Since the molded product is excellent in crack resistance and appearance, it can be suitably used for applications that require decoration of the surface of the molded product, such as meter covers and name plates for automobiles, OA equipment, electrical / electronic equipment, cameras, and the like.

The present invention will be described in detail. Almost all organic substances are oxidized by oxygen and free radicals to produce peroxides. The decomposition of the peroxide is a strong exothermic reaction, and the product carbonyl compound and oxygen are electronically excited and emit photoelectrons upon deactivation. This is chemiluminescence. The chemiluminescence intensity of the PC sheet not subjected to surface treatment is very small. This is presumably because the surface of the PC sheet has no substituent that can be easily oxidized and become a peroxide. On the other hand, it has been found that the surface-modified sheet exhibits a large chemiluminescence intensity which is considered to be due to the generated carboxyl group, carbonyl group, hydroxyl group and the like. In the present invention, the amount of chemiluminescence having a wavelength of 300 nm to 650 nm measured for 30 minutes in a nitrogen atmosphere at 140 ° C. is 30,000 counts to 1,200,000 counts per 1 cm ^{2 of} the measurement surface (1.08 × 10 ^{−14 W / s~4.33 × 10 -13 W /} s), preferably 60,000 counts 1,000,000 counts ^{(2.17 × 10 -14 W / s~3.61} × 10 -13 W / It is a polycarbonate resin molded product that has been surface-treated so as to be s). If the amount of chemiluminescence at a wavelength of 300 nm to 650 nm measured in a nitrogen atmosphere at 140 ° C. for 30 minutes is less than 30,000 counts (1.08 × 10 ⁻¹⁴ W / s) per 1 cm ^{2 of} the measurement surface, surface modification The level is low, the crack resistance is insufficient, and if it exceeds 1,200,000 count (4.33 × 10 ⁻¹³ W / s), the yellowing degree exceeds 2 and the color tone is significantly deteriorated.

In the present invention, the surface treatment is performed so that the chemiluminescence amount at a wavelength of 300 nm to 650 nm measured for 30 minutes in a nitrogen atmosphere at 140 ° C. becomes 30,000 counts to 1,200,000 counts per 1 cm ^{2 of} the measurement surface. Although the modification method for obtaining the polycarbonate resin molded product is not particularly limited, plasma treatment, corona discharge treatment, electron beam irradiation treatment, ultraviolet irradiation treatment and the like are exemplified from the viewpoint of workability. Among them, the ultraviolet irradiation treatment is preferable because the equipment is simple.

  The polycarbonate according to the present invention can be obtained by interfacial polymerization of aromatic dihydroxy or a small amount thereof and a polyhydroxy compound and phosgene, or a branch formed by transesterification of the above aromatic dihydroxy compound and carbonic acid diester. It may be a thermoplastic polycarbonate.

  As aromatic dihydroxy compounds, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane (= tetramethylbisphenol A) 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane (= tetrabromobisphenol A), 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane (= tetrachlorobisphenol A) ), 1,1-bis (4-hydroxyphenyl) cyclohexane, α, α′-bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl, etc., preferably And bisphenol A.

  To obtain a branched polycarbonate, phloroglucin, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-2, 4,6-dimethyl-2,4,6-tri (4-hydroxy) Phenyl) heptane, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-3, 1,3,5-tri (4-hydroxyphenyl) benzene, 1,1,1-tri ( Polyhydroxy compounds represented by 4-hydroxyphenyl) ethane and the like, and 3,3-bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chlorisatin bisphenol, 5,7-dichloroisatin bisphenol Polyhydroxy compounds such as 5-bromoisatin bisphenol are used as part of the dihydroxy compound To do. The amount of the polyhydroxy compound used is, for example, about 0.1 to 2 mol% of the aromatic dihydroxy compound.

  Furthermore, a monovalent aromatic hydroxy compound or the like can be used as a molecular weight regulator. Examples of the molecular weight modifier include m- and p-methylphenol, m- and p-propylphenol, p-bromophenol, p-tert-butylphenol, and p-long chain alkyl-substituted phenol. The amount of the molecular weight modifier used is 0.3 to 10 mol% of the aromatic dihydroxy compound.

  The molecular weight of the polycarbonate resin according to the present invention is a viscosity average molecular weight measured from the viscosity of the methylene chloride solution at 25 ° C., preferably 10,000 to 100,000, more preferably 14,000 to 50,000, Most preferably, it is 18,000 to 35,000. When the viscosity average molecular weight is less than 10,000, the mechanical properties of a polycarbonate resin molded product whose surface is decorated with a treatment agent containing an organic solvent such as coating or printing may be deteriorated. On the other hand, if the viscosity average molecular weight exceeds 100,000, an appearance defect due to the gel-like insoluble matter occurs, which is not preferable.

  Depending on the purpose, the polycarbonate according to the present invention may further contain other additives that impart desired characteristics. For example, one or more antioxidants, heat stabilizers, ultraviolet absorbers, colorants and the like may be added and contained at a blending ratio of less than 1% by weight.

  The polycarbonate molded product according to the present invention can be easily molded by a conventionally known molding method such as an extrusion molding method, an injection molding method, an injection compression molding method, or a compression molding method.

The present invention will be described in more detail with reference to examples below, but the present invention is not limited thereto.
The molding method and processing method of the sample used in the examples and comparative examples, and the evaluation method are shown below.

(1) Molded Viscosity Polycarbonate (Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon E-2000) having a molding viscosity average molecular weight of 28,000 is extruded with a vent of L / D35 with a screw diameter of 65 mm and L / D35. Polycarbonate with a thickness of 0.5 mm, melted and kneaded by a machine, passed through a T-die with a width of 600 mm set at 270 ° C., and cooled with three polishing rolls with a surface temperature set at 130 ° C. to 200 ° C. The sheet was formed and cut into 40 mm × 400 mm, and then surface treatment was performed. Using the molded product, chemiluminescence measurement, color tone measurement, and printing test were performed.

(2) Surface treatment conditions of molded product (2-1) Ultraviolet irradiation treatment condition-1: Nippon Battery Co., Ltd. high pressure mercury lamp EHAL1400SL, output 120 W / cm, light source distance 80 mm, sample moving speed 1.3 m / min, Irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “ultraviolet ray-1”. (2-2) Ultraviolet irradiation treatment condition-2: High pressure mercury lamp EHAL1400SL manufactured by Nippon Batteries Co., Ltd., output 120 W / cm, light source distance 250 mm, sample moving speed 2 .6 m / min, irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “UV-2” (2-3) UV irradiation treatment condition-3: Nippon Battery Co., Ltd. high pressure mercury lamp EHAL1400SL, output 66 W / cm, light source distance 250 mm, sample moving speed 2 .6 m / min, irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “ultraviolet ray-3” (2-4) UV irradiation treatment condition-4: Nippon Battery Co., Ltd. high pressure mercury lamp EHAL1400SL, output 30 W / cm, light source distance 250 mm, sample moving speed 2 .6 m / min, irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “ultraviolet ray-4”. (2-5) Ultraviolet irradiation treatment condition-5: High-pressure mercury lamp HI-32SL manufactured by Nippon Battery Co., Ltd., output 30 W / cm, light source distance 250 mm, sample movement Speed 6 m / min, irradiation atmosphere nitrogen, sheet temperature 23 ° C.
Hereinafter, this surface treatment condition is abbreviated as “UV-5” (2-6) UV irradiation treatment condition-6: High-pressure mercury lamp HI-32N manufactured by Nippon Battery Co., Ltd., output 30 W / cm, light source distance 250 mm, sample movement Speed 6 m / min, irradiation atmosphere nitrogen, sheet temperature 23 ° C.
Hereinafter, this surface treatment condition is abbreviated as “ultraviolet-6”. (2-7) Ultraviolet irradiation treatment condition-7: High pressure mercury lamp HI-32N manufactured by Nippon Battery Co., Ltd., output 30 W / cm, light source distance 380 mm, sample movement Speed 6 m / min, irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “ultraviolet-7”. (2-8) Ultraviolet irradiation treatment condition-8: High-pressure mercury lamp HI-32N manufactured by Nippon Battery Co., Ltd., output 30 W / cm, light source distance 380 mm, sample movement Speed 10 m / min, irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “UV-8” (2-9) UV irradiation treatment condition-9: High pressure mercury lamp HI-32N manufactured by Nippon Battery Co., Ltd., output 30 W / cm, light source distance 380 mm, sample movement Speed 20 m / min, irradiation atmosphere Air, sheet temperature 100 ° C.
Hereinafter, this surface treatment condition is abbreviated as “UV-9”.

(3) Measurement of chemiluminescence amount For each of Examples 1 to 7 and Comparative Examples 1 to 3, the chemiluminescence amount was measured under the following conditions with CLD-110 / CLC-10 manufactured by Tohoku Electronics Industry Co., Ltd. It was.
Measurement wavelength range: 300 nm to 650 nm
1 count: 3.61 × 10 ⁻¹⁹ (W / s)
Sample measurement surface area: 9 cm ²
Measurement temperature: 140 ° C. Constant-temperature measurement cell nitrogen gas flow rate: 1 L / min
Measurement time: Calculation of chemiluminescence amount for 30 minutes from 5 seconds after placing the sample in the measurement cell is performed as follows. Assuming that the chemiluminescence amount of each sample for 30 minutes is (Cx) and the background chemiluminescence amount measured under the same conditions with no sample is (Cy), 30 minutes for each sample. amount of chemiluminescence per 1 cm ² (Cz counts ^/ cm 2 ^/ 30min) is calculated from equation 1.
Cz (counts ^{/ cm 2 / 30min) = (} Cx-Cy) / 9cm 2 ··· Formula 1

(4) Color tone evaluation About each of Examples 1-7 and Comparative Examples 1-3, the degree of yellowing was measured with SZ-Σ90 manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Printing Test Examples 1 to 7 and Comparative Examples 1 to 3 were obtained from 100 parts by weight of ink (Teikoku 13-000, slow dry medium) and 30 parts by weight of solvent (Teikoku G004). The resulting ink composition was applied to a molded product so that the thickness before drying was 120 μm, air-dried at 25 ° C. for 1 hour, and then hot-air dried at 100 ° C. for 10 minutes.
(6) Evaluation of crack resistance: The printed surface was visually observed and evaluated as follows.
A: No crack is observed on the printed surface.
X: A crack was observed.
(7) Appearance evaluation: The printed surface was visually observed and evaluated as follows.
A: Glossy printed surface.
○: The printed surface is slightly inferior in gloss.
X: Glossy printed surface.

Examples 1-7
The sheet molded article was subjected to surface modification by the method shown in [0024], and then a chemiluminescence amount measurement, a yellowing degree measurement, and a printing test were performed. The evaluation results are shown in Table 1. From Table 1, in the invention, a polycarbonate molded product having a chemiluminescence amount of 300 nm to 650 nm measured in 30 minutes in a nitrogen atmosphere at 140 ° C. and having a 30,000 count to 1,200,000 count per 1 cm ^{2 of} the measurement surface It was confirmed that the molded product was excellent in crack resistance and appearance.

Comparative Examples 1-3
Comparative Example 1 was not subjected to surface modification, Comparative Example 2 was subjected to surface modification under UV treatment condition-9 in the [0025] column, and Comparative Example 3 was subjected to surface modification under UV treatment condition-1 in the [0026] column. Tests were performed under the same conditions as in Examples 1 to 7, and the evaluation results are shown in Table 1. From Table 1, in the invention, the molded article of Comparative Example 2 having a chemiluminescence amount of a wavelength of 300 nm to 650 nm measured in a nitrogen atmosphere at 140 ° C. for 30 minutes is less than 30,000 counts per 1 cm ^{2 of} the measurement surface is crack resistant. It was found that the molded product was inferior in properties. In addition, in the invention, the molded product of Comparative Example 3 having a chemiluminescence amount of 300 nm to 650 nm measured in 30 minutes under a nitrogen atmosphere of 140 ° C. over 1,200,000 counts per 1 cm ^{2 of} the measurement surface is yellowed. It was found to be unsuitable for practical use.

Claims (6)

Molded polycarbonate resin surface-treated so that the amount of chemiluminescence at a wavelength of 300 nm to 650 nm measured in a nitrogen atmosphere at 140 ° C. for 30 minutes is 30,000 counts to 1,200,000 counts per 1 cm ^{2 of} the measurement surface. Goods. The molded article according to claim 1, wherein the molded article is a sheet. A molded product obtained by decorating the surface of the molded product according to claim 1 with a treating agent containing an organic solvent. Treatment of a polycarbonate molded article subjected to surface treatment so that a chemiluminescence amount of a wavelength of 300 nm to 650 nm measured in a nitrogen atmosphere at 140 ° C. for 30 minutes is 30,000 counts to 1,200,000 counts per 1 cm ^{2 of} the measurement surface. Method. The processing method according to claim 4, wherein the molded product is a sheet. The processing method which decorates the surface of the molded article which performed the process of Claim 4 with the processing agent containing an organic solvent.