JPH0324501B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass-reinforced polycarbonate resin composition suitable for molding, which has improved adhesion of paint, printing ink, etc. to the surface of a glass-reinforced polycarbonate resin molded product. Polycarbonate resin reinforced with glass-based fillers (hereinafter referred to as "glass-reinforced polycarbonate resin") exhibits various excellent performances such as dimensional stability, mechanical strength, heat resistance, and electrical properties, so it is used in cameras and VTRs. , facsimile, etc. are used in a wide range of industrial fields. However, despite their excellent performance, injection molded products using glass-reinforced polycarbonate resin do not have a beautiful appearance. When used for parts,
In order to give molded products a good appearance, painting has had to rely on secondary processing such as printing, and as a result, the adhesion between the base material and the coating film or printing ink has become a problem. Unlike molded products made of glass-reinforced polycarbonate resin, satisfactory adhesion cannot be obtained even with paints that show good adhesion to molded products made of non-reinforced polycarbonate resin. Sometimes. As a result of investigating the cause, the present inventors found that
It was discovered that this is due to the unique condition of the surface layer of the glass-reinforced polycarbonate resin molded product. That is, when a glass-reinforced polycarbonate resin molded product obtained by injection molding is used, cellophane tape is attached to the surface of the product, and the tape is rapidly peeled off, it is observed that the surface layer peels off in an wafer-like manner. Ta. In order to explain its condition, we observed the surface using a scanning electron microscope (JEOL Ltd.
Co., Ltd., model JSM255, magnification: 300) The results are shown in Figure 1 (before adhesion of cellophane tape) and Photo 2 (after peeling). This phenomenon is more likely to occur when the surface of a molded article is made as smooth as possible with the intention of painting it. Furthermore, when painted on this smooth molded product surface,
For the reasons mentioned above, the coating peels off together with the underlying layer, ie, the surface layer of the molded article. In this case, it has been found that when the coating film is made thinner in order to reduce costs, the effect becomes even more pronounced. The inventors of the present invention have carried out extensive research in order to eliminate these drawbacks of glass-reinforced polycarbonate resins, and as a result, the inventors have found that by blending a specific aromatic carbonate oligomer into a mixed system of aromatic polycarbonate resin and glass filler. The inventors have now found that a glass-reinforced polycarbonate resin composition can be obtained which solves the above-mentioned defects and gives molded products with good adhesion to paints, printing inks, etc., and the present invention has been completed. In order to clarify the features of the resin composition of the present invention, it will be explained using a photograph taken by a scanning electron microscope of a fractured surface including the surface layer of a molded article obtained using the resin composition of the present invention. First, Drawing 3 shows a fractured surface including the surface layer of a molded article obtained using the resin composition of the present invention, and as can be seen from this drawing (photo), cavities are observed around the glass fibers. ,
This means that the resin and glass fiber are not in close contact with each other. Furthermore, when each part of the fractured surface is observed in detail, it is surprisingly found that the skin layer near the surface of the molded article is formed almost entirely of resin, unlike the inner layer. On the other hand, when we observe the fractured surface including the surface layer of a molded product obtained using a resin composition consisting only of polycarbonate resin and glass fiber, which causes peeling of the surface layer of the molded product, we find that the surface layer of the molded product peels off. There is virtually no difference between the inner layer and the inner layer, and it can be seen that glass fibers are present in the surface layer as well. As is clear from these observations, when the resin composition of the present invention is used, the glass fibers are submerged from the outer layer to the inner layer due to the unique effect of the aromatic carbonate oligomer, making it look like a two-layer structure with two cylinders. The result is a molded product in which the skin layer and inner layer are separated, as if molded by an injection molding machine. In this way, the surface layer of the injection molded article obtained using the resin composition of the present invention becomes strong and has cellophane tape peeling resistance, and the adhesion between the paint or printing ink and the molded article surface is remarkable. This led to improvements. The aromatic polycarbonate resin used in the present invention is typically 2,2-bis(4-hydroxyphenyl)-propane or 2,2-bis(3,5-dibromo-4-hydroxyphenyl)-propane. It is a polymer known per se, obtained by reacting one or more divalent phenolic compounds exemplified by a carbonate precursor typically exemplified by phosgene, by a known method. A suitable molecular weight is in the range of 19,000 to 30,000 in terms of viscosity average molecular weight. Next, the glass-based filler used in the present invention refers to a filler selected from the group consisting of glass fibers, glass beads, and glass flakes, and these may be used alone or in combination. It is a short fiber with a diameter of 5 to 15 μm and a length of 0.02 to 10 mm, such as the product name "Glaslon Chopped Strand" or "Glaslon Milled Fiber" manufactured by Asahi Fiber Glass Co., Ltd. or Nippon Sheet Glass Co., Ltd.
Glass beads with an outer diameter of 10 to 100 μm can be mentioned.
For example, Toshiba Balloteini Co., Ltd.
The glass flakes are plate-shaped with a thickness of 1 to 20 μm and a side length of 0.05 to 1.0 mm, such as Nippon Sheet Glass. Examples include those commercially available under the trade name "Micro Glass Flake CEF-48" manufactured by Co., Ltd. The amount of the glass filler added may be selected within the range of 5 to 50% by weight of the total composition of the present invention, and when it is less than 5%, dimensional stability (low shrinkage rate),
It is inferior in terms of strength or rigidity, and cannot function as a glass-reinforced resin material. On the other hand, if it exceeds 50%, it may become difficult to mold due to lack of fluidity.
The wear of molds and cylinders increases, which is economically disadvantageous. The most preferable range is 8 to
It is 40% by weight. Further, the aromatic carbonate oligomer used in the present invention refers to a low molecular weight polycarbonate having an average of 2 to 15 repeating structural units represented by the following formula. formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, and each may be the same or different, (X is a substituted or unsubstituted alkylidene group having 1 to 5 carbon atoms, an oxygen atom, a sulfur atom, or a sulfonyl group.) This aromatic carbonate oligomer has 2,2
-bis(4-hydroxyphenyl)propane,
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-
It is obtained by the reaction of an aromatic dihydric phenol compound typically exemplified by dimethyl-4-droxyphenyl)propane with a carbonate precursor typified by phosgene. Generally speaking, the oligomers are low molecular weight substances having an intrinsic viscosity of 0.3 or less at 25° C. in methylene chloride. When preparing this oligomer, the molecular weight may be adjusted by adding phenol and/or alkyl-substituted phenol to the polymerization system to block the ends, for example, in an interfacial polymerization method using phosgene. The amount of the aromatic carbonate oligomer thus obtained may be selected within the range of 2 to 30% by weight based on the total amount of the composition of the present invention, and if it is less than 2%, the amount of the aromatic carbonate oligomer added may be selected to be within the range of 2% to 30% by weight of the total amount of the composition of the present invention. It has little effect on preventing peeling, and on the other hand, if it exceeds 30%, the average molecular weight of the entire polycarbonate resin that makes up the composition decreases, causing problems in physical properties such as stress cracking properties, which is disadvantageous. It is. The most preferred range is 5-20% by weight. The method for preparing the composition of the present invention is not particularly limited, and for example, polycarbonate resin, carbonate oligomer, and glass fiber are thoroughly mixed in a V-type blender, and then pelletized in a vented single-screw extruder. First, prepare a mixture of polycarbonate resin and carbonate oligomer sufficiently mixed in a powerful mixer such as a super mixer, and when extruding this using a vented twin-screw extruder, add glass from the middle of the extruder. Methods commonly used in industry can be applied, such as feeding, mixing, and extruding fibers into pellets. In addition, lubricants such as fatty acid esters, paraffin wax, and silicone oil; internal plasticizers such as polyethylene, ABS, and polyethylene terephthalate; and various other additives may also be added to this composition as necessary. . Comparative examples and examples will be specifically described below. Example 1 [Production of aromatic carbonate oligomer (number average degree of polymerization 7)] In a reaction tank with an internal capacity of 400 mm equipped with a stirrer, a phosgene gas blowing pipe, and a cooling jacket, 25 kg of a 48% by weight caustic soda aqueous solution, 250 ml of aqueous sodium hydroxide solution, and methylene chloride were added. 60, 100 g of hydrosulfite and 27.5 kg of bisphenol A were successively added, and 15 kg of phosgene was blown in over 30 minutes while maintaining the liquid temperature in the range of 15°C to 2°C to cause a reaction. After that, 6 kg of 48 wt% caustic soda aqueous solution and 100 g of triethylamine were added to the reaction system.
g and p-tert-butylphenol 5.2Kg
Add a solution of 50% of methylene chloride,
Stirring was continued for an additional 60 minutes. The precipitated methylene chloride phase was extracted and transferred to a 300 volume purification tank equipped with a stirrer, neutralized with 1% phosphoric acid aqueous solution of 100 parts each and water, and washed with water. The content of the purified methylene chloride solution is
The mixture was transferred to a 500 ml solidification tank and heated with 300 ml of water while stirring to distill off methylene chloride. After cooling,
The precipitate was separated and dried to obtain 33.6 kg of aromatic carbonate oligomer powder. The melting point of the obtained carbonate oligomer is
At 229-232°C, the viscosity average molecular weight was 5 x 1000, and the number average molecular weight by end group analysis was 2.1 x 1000. Example 2 [Production of aromatic polycarbonate oligomer (number average degree of polymerization 10)] In the production method of Example 1, the amount of phosgene was
14.6Kg, p-tert-butylphenol amount
33 kg of aromatic carbonate oligomer powder was obtained in exactly the same manner except that the powder was 3.6 kg. The melting point of this product is 235-238℃, and the viscosity average molecular weight is 7×
1000, and the number average molecular weight was 2.9×1000. Examples 3 to 7 and Comparative Examples 1 to 2 Polycarbonate resin powder, glass filler, and aromatic carbonate oligomer obtained in Example 1 were mixed in a tumbler in the proportions shown in Table 1, and each was uniaxially mixed. It was pelletized using a vented extruder. 120 pellets of each composition obtained
After drying for 6 hours in a hot air circulation dryer at ℃, a cylindrical molded product was molded using a Neomat 350/120 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. The molded product is a cylindrical molded product with an outer diameter of 58 mm, a thickness of 2 mm, and a height of 25 mm. The molding conditions are resin temperature of 320°C, mold temperature of 90-100°C, holding pressure of 1000 Kg/cm ² , and injection speed of 60 mm. /second and molding cycle 50 seconds (cooling time 25 seconds, injection time 1 second and hold time 7 seconds). The obtained molded product was subjected to a peel test on the surface of the molded product using cellophane tape and a grid test after painting, and the results are summarized in Table 1. As is clear from Table 1, it is recognized that the adhesion of the coating film of the molded article using the composition of the present invention is improved. 【table】

[Brief explanation of the drawing]

Figures 1 to 4 show the state of dispersion of glass fibers in a glass fiber-reinforced polycarbonate resin molded product and the accompanying surface structure of the resin molded product, as seen using a scanning electron microscope. The surface of the conventional formulation; Figure 2 is the surface of the formulation shown in Figure 1 with cellophane tape applied and removed; Figure 3 is the fractured surface including the surface of the invention; Figure 4 is the conventional formulation. The fracture surface includes the surface of the product. It can be seen that the molded article of the present invention shown in FIG. 3 has a skin layer that does not contain glass fibers. The numbers in the figure are 1...surface layer, 2...
...Skin layer, 3...Glass fiber, 4...Matrix resin. The electron microscope is manufactured by JEOL Ltd.
A JSM255-type was used, and the magnification was 300x.

Claims (1)

[Claims] 1. A composition consisting of (a) an aromatic polycarbonate resin, (b) a glass filler, and (c) an aromatic carbonate oligomer having an average of 2 to 15 repeating structural units represented by the following formula: A polycarbonate resin composition for molding, wherein the component (b) accounts for 5 to 50% by weight of the total composition, and the component (c) accounts for 2 to 30% by weight of the total composition. formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, and each may be the same or different, and X is a substituted or unsubstituted alkylidene group having 1 to 5 carbon atoms, an oxygen atom, a sulfur atom, or a sulfonyl group.) 2. The glass filler is selected from the group consisting of glass fibers, glass flakes, and glass beads. A resin composition according to claim 1.