JPS6212815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polycarbonate resin compositions. More specifically, the present invention relates to a polycarbonate resin composition containing an inorganic filler of glass powder and/or glass beads and having excellent physical properties.

Polycarbonate resin is widely used as an engineering plastic with excellent toughness, transparency, impact resistance, and electrical properties. In addition, glass fiber-reinforced polycarbonate resins containing glass fibers are also widely used industrially to take advantage of polycarbonate's good heat resistance, provide further rigidity, and reduce mold shrinkage.

Compared to non-reinforced polycarbonate resin, glass fiber reinforced polycarbonate resin has a heat distortion temperature that is approximately 10°C higher, and as the amount of glass fiber added increases, the rigidity increases, and the coefficient of thermal expansion decreases, resulting in improved dimensional accuracy. It has characteristics such as improved hardness and is used in areas where rigidity or dimensional stability is required.

However, products molded using glass fiber-reinforced polycarbonate resin have a problem in the product design stage because the mold shrinkage rate or physical properties change depending on the degree of orientation of the glass fibers, resulting in so-called anisotropy. It's summery.

On the other hand, in order to eliminate this anisotropy, a method of adding an inorganic filler such as glass powder, glass beads, or an inorganic filler has been proposed.
By adding these fillers, the anisotropy can be reduced and a resin composition having a certain degree of rigidity can be obtained. However, the impact resistance of the resin composition thus obtained is significantly reduced and the characteristics of polycarbonate resin are lost, which poses a practical problem.

As a result of various studies to solve these problems, the present inventor has developed a polycarbonate resin composition whose physical properties are significantly improved by adding a specific wax and which has impact resistance comparable to that of glass fiber-reinforced polycarbonate. The present invention was achieved based on the discovery that the following can be obtained.

That is, the present invention provides an aromatic polycarbonate of 50 to
95%, glass powder and/or glass beads 5
50% by weight, glass fiber 0-30% by weight, and polyethylene wax 0.01-3% by weight.

The aromatic polycarbonate used in the present invention is a polymer produced from an aromatic dihydroxy compound and a carbonate precursor, and is generally produced by a solution method using an aromatic dihydroxy compound and phosgene or a melt method using an aromatic dihydroxy compound and diallyl carbonate. It can be manufactured using As the aromatic dihydroxy compound, 2,2bis(4
-hydroxyphenyl)propane [bisphenol A], bis(4-hydroxyphenyl)methane, 2,2bis(4-hydroxy3-methylphenyl)propane, 2,2bis(3,5-dibrom4-hydroxyphenyl) Examples include 2,2bis(3,5-dichloro4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfide, and bis(4-hydroxyphenyl)sulfone. Among these, bis(4-hydroxyphenyl)alkane compounds, particularly bisphenol A, are preferred. The aromatic dihydroxy compounds may be used alone or in combination of two or more. The carbonate precursor used may be a carbonyl halide, diallyl carbonate or haloformate. Well-known examples include phosgene and diphenyl carbonate.

The aromatic polycarbonate used in the present invention is produced from an aromatic dihydroxy compound and a carbonate precursor, but different types of aromatic polycarbonates may be mixed together. The molecular weight of aromatic polycarbonate is generally 10,000 to 100,000,
Preferably it is 15,000 to 60,000. In producing aromatic polycarbonates having these molecular weights, a suitable molecular weight regulator may be used. Also, a catalyst to accelerate the reaction or a branching agent to improve processability can be used. Furthermore, depending on the use, suitable stabilizers such as antioxidants, heat stabilizers, ultraviolet absorbers, flame retardants, antistatic agents, mold release agents, blowing agents, etc. may be added to the aromatic polycarbonate. good. Furthermore, inorganic fillers other than glass powder and glass beads can be added as necessary.

The glass powder used in the present invention is obtained by shredding or crushing glass fibers, and is also known as milled fiber. Glass powder usually has a fiber diameter of 8 to 20μ and a glass fiber length of 30 to 200μ. The glass powder may be surface-treated to increase its affinity with the resin. The glass powder used in the present invention is particularly preferably made of E-glass, but any powder that does not significantly decompose the aromatic polycarbonate can be used.

Further, the glass beads used in the present invention are glass spheres having a minute diameter. The glass beads used are usually 3 to 100 microns, preferably 5 to 60 microns. Like the glass powder, glass beads made of E-glass are particularly preferred, but any material that does not significantly decompose the aromatic polycarbonate can be used. Furthermore, the glass beads may also be surface-treated to improve their affinity with the resin. The content of glass beads and/or glass powder is 5 to 50% by weight, and any of them will have the same effect in eliminating anisotropy in the molded product. If the addition amount is less than 5% by weight, no improvement in rigidity is observed, and 50
Exceeding this percentage by weight is not preferable because moldability deteriorates.

The resin composition of the present invention may contain glass fiber. Any glass fiber that is normally used for aromatic polycarbonate may be used. The diameter of the glass fibers is 9 to 20 μm, and the length of the glass fibers in the pellet is 0.15 to 6 m/m. Further, the glass fiber may be surface-treated to improve its affinity with the resin. As the ratio of glass fibers and glass beads and/or glass powder increases, anisotropy appears as the ratio of glass fibers increases.
The ratio by weight is preferably 2 parts glass fiber to 1 part or more of glass beads and/or glass powder.

Further, the polyethylene wax used in the resin composition of the present invention is low molecular weight polyethylene or partially hydrophilized wax having a molecular weight of about 1,500 to 10,000. These waxes include, for example, Hiwax (manufactured by Mitsui Petrochemicals), Hoechst Wax; PA190, PA520.
(manufactured by Hoechst) and others.
The content of polyethylene wax in the resin composition is 0.01 to 3% by weight. Although polyethylene wax is generally known as a lubricant, it is an unexpected fact that in the resin composition of the present invention, a significant effect of improving impact strength can be exhibited by just adding a small amount of polyethylene wax. If the content of the polyethylene wax is less than 0.01% by weight, no effect of its addition will be observed, and if it exceeds 3% by weight, the moldability will be markedly deteriorated, which is not preferred. Next, in producing the resin composition of the present invention, any known method may be used. For example, a method of extruding a mixture of aromatic polycarbonate, glass powder and/or glass beads, and polyethylene wax using a single-screw or multi-screw extruder;
Method of kneading aromatic polycarbonate to which glass powder and/or glass beads have been added and polyethylene wax; Pelletization by kneading aromatic polycarbonate to which polyethylene wax has been added and glass powder and/or glass beads, or the above method. Examples include a method of forming a molded article by direct injection molding a mixture of any of the above, but the characteristics of the resin composition of the present invention are expressed no matter which method is used.

The resin composition of the present invention may contain various stabilizers depending on the use. It is also possible to add plasticizers which improve processability. Further, other resins such as resins containing polyolefin rubber components may be added to the extent that the essential properties of the aromatic polycarbonate are not impaired.

The resin composition of the present invention not only provides molded products with low anisotropy, but also has significantly improved impact resistance, so it can be used in various applications that have not been used conventionally due to such problems. There is expected. It is a useful industrial material.

The method of the present invention will be illustrated below with examples, but the method is not necessarily limited thereto. It should be noted that the impact values described in the examples are values for test pieces with an impact of 3.2 m/m and an impact of Kgfcm/cm with isotto notches.

Example 1 Aromatic polycarbonate resin (molecular weight 24700) made from bisphenol A (molecular weight 24,700) 89.3% by weight, glass beads (Toshiba Balloteini EGB731) 10% by weight and polyethylene wax (Hiwax)
400P) was extruded into pellets at a cylinder temperature of 280°C. The obtained pellets were dried at 120°C for 6 hours and then molded into physical property test pieces using an injection molding machine. Impact test piece at 23℃, 50
After conditioning the humidity at %RH for 4 hours, the impact value was measured and found to be 9.0.

For comparison, the impact value was 4.1 when the same procedure as above was performed except that no polyethylene wax was added.

Example 2 When glass powder (Nittobo PFA) was used in place of the glass beads in Example 1, the impact value was 11.2.

For comparison, the same procedure as above was performed except that no polyethylene wax was added, and the impact value was 5.1.

Example 3 69% by weight of aromatic polycarbonate made from bisphenol A, glass beads (manufactured by Kyoritsu Ceramics)
The impact value was measured in the same manner as in Example 1, except that pellets consisting of 30% by weight and 1.0% by weight of polyethylene wax (Hoechst Wax PA190) were used, and the impact value was 6.5.

For comparison, the same procedure as above was performed except that polyethylene wax was not added, and the impact value was
It was 2.6.

Example 4 When the glass powder used in Example 2 was used in place of the glass beads in Example 3, the impact value was 15.5.

Also, when the molding shrinkage rate was measured with this composition,
0.55% in the flow direction, 0.60% in the direction perpendicular to the flow
, and no anisotropy was observed.

For comparison, the same procedure as above was carried out except that no polyethylene wax was added, and the impact value was 2.5. Moreover, no difference was observed in the molding shrinkage rate with and without the addition of polyethylene wax.

Example 5 79.2% by weight of aromatic polycarbonate made from bisphenol A, 14.9% by weight of glass powder, 5% by weight of glass fiber (chopped strand), and polyethylene wax (high wax).
An impact test piece was prepared by direct injection molding of a mixture consisting of 400P) 0.9PHR, and the impact value was measured in the same manner as in Example 1. The impact value is 8.5, and the molding shrinkage rate is 0.50% in the flow direction and perpendicular to the flow direction.
It was 0.65%.

Claims (1)

[Claims] 1. A polycarbonate resin composition comprising 50 to 95% by weight of aromatic polycarbonate, 5 to 50% by weight of glass powder and/or glass beads, 0 to 30% by weight of glass fiber, and 0.01 to 3% by weight of polyethylene wax.