JPH04100830A - Lowly anisotropic high-rigidity glass fiber-reinforced resin molding - Google Patents

Abstract

PURPOSE:To obtain the title molding lowly anisotropic in molding shrinkage and mechanical strengths by mixing an aromatic polycarbonate with specified glass fibers in a specified ratio. CONSTITUTION:This molding comprises 20-50 pts.wt. aromatic polycarbonate (e.g. Upilon S-2000, a product of Mitsubishi Gas Chemical Co.) and 50-80 pts.wt. glass fibers of a number-average aspect ratio of 4-10.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an aromatic polycarbonate glass fiber reinforced molded product that has excellent mechanical strength, particularly rigidity, heat resistance, and electrical properties, and has low anisotropy. Yes, industrial parts, electrical/
Can be used in a wide range of fields such as electronic parts, transportation parts, and miscellaneous goods.
In particular, it can be suitably used for precision molded products that require dimensional accuracy and high rigidity.

[Conventional technology and issues]

Conventionally, it has been known that glass fibers are blended with aromatic polycarbonate resin to obtain molded products with excellent heat resistance, mechanical strength, electrical properties, etc., but fiber orientation affects mold shrinkage rate and mechanical strength. It exhibits anisotropy, causing warping in molded products, which often poses a practical problem.

In order to improve the above-mentioned anisotropy, it is possible to change the wall thickness of the molded product or the gate position, but it is not possible to obtain sufficiently satisfactory results. Next, it is conceivable to use a plate-shaped filler such as mica or talc alone or in combination with glass fiber, but the aromatic polycarbonate decomposes during melt-kneading, causing poor appearance and a decrease in mechanical strength. On the other hand, compositions in which anisotropy is reduced by using glass fibers and glass beads in combination are also known. However, when used in combination with glass beads, there was almost no improvement in mechanical properties such as bending strength and bending modulus.

[Means to solve the problem]

As a result of intensive studies to solve the above problems, the present inventors found that a molded product containing glass fibers having a specific aspect ratio in an aromatic polycarbonate resin has improved mechanical properties and anisotropic molding shrinkage rate. The present invention has been achieved based on the discovery that the properties are also significantly reduced. That is, in the present invention, 20 to 50 parts by weight of aromatic polycarbonate and 50 to 80 parts by weight of glass fibers having a number average aspect ratio of 4 to 10 are used.
This is a low-anisotropy, high-rigidity glass fiber reinforced resin molded product characterized by containing part by weight.

The configuration of the present invention will be explained below.

The aromatic polycarbonate resin used in the molded article of the present invention is an optionally branched thermoplastic aromatic polycarbonate resin obtained by reacting an aromatic dihydroxy compound or a small amount of a polyhydroxy compound with a diester of phosgene or carbonic acid. It is a combination. Examples of aromatic dihydroxy compounds are 2,2-bis(4-hydroxyphenyl)furopane (=bisphenol A), and tetrahydrobisphenol A1 bis(4-hydroxyphenyl).
-p-diisopropylbenzene, hydroquinone, resorcinol, 4-4°-dihydroxydiphenyl, etc., with bisphenol A being particularly preferred.

In addition, to obtain a branched aromatic polycarbonate resin,
Phloroglycine, 4,6-dimethyl-2.4.6-tri(4-hydroxyphenyl)hebutene-2,4,6-dimethyl-2.4.6-1-li(4-hydroxyphenyl)hebutane, 2 .6-dimethyl-2.4.6-1-ly(
4-Hydroxyhebutene-3,4,6-dimethyl-2.
4.6-tri(4hydroxyphenyl)hebutane,
1,3.5-)su(4hydroxyphenyl)benzene,
Polyhydroxy compounds exemplified by 1,1.1-toIJ (4hydroxyphenyl)ethane, and 3.3-
Bis(4-hydroxyaryl)oxindole (=
isatin (bisphenol)), 5-chloroisatin,
5.7-dichloroisatin, 5-bromoisatin, etc. are substituted with a polyhydroxy compound for a portion of the dihydroxy compound, for example, 0.1 to 2 mol %. Monoaromatic hydroxy compounds suitable for controlling the molecular weight include m- and p-propylphenol, p-bromophenol, p-
-tert-butylphenol and p-long chain alkyl-substituted phenol are preferred. Typical examples of aromatic polycarbonate resins include polycarbonates based on bis(4-hydroxyphenyl)alkane compounds, particularly bisphenol A, which can be obtained by using two or more aromatic dihydroxy compounds in combination. Branched polycarbonates obtained by using a small amount of a polycarbonate copolymer and a trivalent phenol compound can also be mentioned.

Aromatic polycarbonate resins may be used as a mixture of two or more.

The glass fibers used in the present invention are so-called E-glass fibers in the form of chopped strands, roving strands, milled fibers, etc., and these glass fibers are treated with coupling agents, organic compounds with oxazolidone rings, and other substances. Those treated with a surface treatment agent can also be suitably used, and those that are usually used in a concentrated form can also be used.

The aromatic polycarbonate resin of the low anisotropy glass fiber reinforced resin molded article of the present invention is preferably 20 to 50 parts by weight. If the amount of aromatic polycarbonate is less than 20 parts by weight, molding becomes extremely difficult.

The low anisotropy high rigidity glass fiber reinforced resin molded product of the present invention is
It is usually manufactured by injection molding using a composition formed by blending glass fiber with the aromatic polycarbonate resin component, and the number average aspect ratio of the glass fiber in the molded product is in the range of 4 to 10. It is characterized by: Here, the number average aspect ratio of glass fiber is 1
If it is larger than 0, (molding shrinkage rate in the resin flow direction) <
(molding shrinkage rate in the direction perpendicular to the resin flow). On the contrary, 4
If it is smaller, (molding shrinkage rate in the resin flow direction)〉
(molding shrinkage rate in the direction perpendicular to the resin flow), and
This is not preferable because it also causes a large decrease in strength.

The blending ratio of glass/A fiber can be appropriately selected from the range of 50 to 80 parts by weight based on 20 to 50 parts by weight of the resin component. If it exceeds 80 parts by weight, molding becomes difficult;
If it is less than 50 parts by weight, the improvement in mechanical strength, particularly rigidity, will be insufficient, which is not preferred.

The low anisotropy high rigidity glass fiber reinforced resin molded product of the present invention is
The resin component and glass fiber are melt-kneaded in an extruder to form pellets, which are manufactured by injection molding.

In the present invention, it is preferable to select glass fibers having a number average aspect ratio of 5.5 to 14 as the molding material.

The method for producing pellets or molding materials is to use pellets with a number average aspect ratio of about 6 to 24, or
Alternatively, there are various methods such as extruding twice using glass fibers with a regular length of about 3 to 5 mm, or manufacturing using a twin-screw extruder of high kneading type that easily crushes glass fibers. .

As desired, various additives such as stabilizers, pigments, dyes, flame retardants, and lubricants can be added to the low-anisotropy glass fiber molded article of the present invention as described above. Other resin components may be added to the extent that they do not adversely affect the composition.

[Example, comparative example]

Hereinafter, a specific explanation will be given by giving Examples and Comparative Examples.

Examples 1 to 7, Comparative Examples 1 to 4 Aromatic polycarbonate resin [manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name Newpilon S-2000, viscosity average molecular weight 2400]
0 (hereinafter referred to as PC8), Kneepilon H-3000,
Viscosity average molecular weight 18,000 (hereinafter abbreviated as PCII)]
Glass fiber (hereinafter referred to as GFL) with a diameter of 9 μm and a length of 3 mm
), glass fiber with a diameter of 9 μm and an average fiber length of 70 μm (hereinafter referred to as G
FM) were mixed in the proportions (parts by weight) listed in Table 1.

These mixtures were melt-kneaded and extruded using a single-screw extruder with a screw diameter of 40 mm or a twin-screw extruder with a screw diameter of 30 mm at a cylinder temperature of 280° C. to obtain pellets.

After pre-drying the obtained pellets at 120°C for 5 hours,
As a mold, the gate is 2mm thick and 30mm wide, 4X
Using a 100 x 100 mm flat plate, use a screw injection molding machine with a cylinder temperature of 310°C and a mold temperature of 1.
Injection molding was carried out at 00°C, injection pressure of 1200 kg/cm2, and molding cycle of 60 seconds.

The number average aspect ratio of glass fibers, molding shrinkage rate, bending elastic modulus, and bending strength of the obtained flat plate-like molded product were measured, and the results are shown in Table 1.

Next, the test method for the test items shown in Table 1 will be explained.

Aspect ratio: Sample from the center of the flat molded product, and measure the length of approximately 20,000 or more fibers per sample for glass fibers of 10 μm or more.
Measurement was performed using a 0-type image analyzer to determine the number average aspect ratio.

Molding shrinkage rate (%) was measured using a two-dimensional dimension measuring machine.

P direction: Flow direction of molten resin (from the side with the gate to the opposite side) V direction: Bending strength in the direction perpendicular to the flow direction of molten resin (k
g/cm2), flexural modulus (kg/cm2): Width 12.7 mm and length 63.5 mm from the center of the flat molded product
A test piece was cut out and measured at 23°C using a Toyo Seiki bentograph.

[Operation and effect of the invention]

The low anisotropy high rigidity glass fiber reinforced resin molded product of the present invention is
It has excellent rigidity with a bending modulus of 10.000 kg/cnf or more, and has reduced mold shrinkage and anisotropy in mechanical strength. Therefore, the low anisotropy, high rigidity glass fiber reinforced resin molded product of the present invention takes advantage of its high rigidity and low anisotropy, and is extremely useful as a precision molded product in a wide range of fields.

Claims (1)

[Claims] 1. Low anisotropy, high rigidity glass fiber reinforced resin molding characterized by comprising 20 to 50 parts by weight of aromatic polycarbonate and 50 to 80 parts by weight of glass fibers having a number average aspect ratio of 4 to 10. Item 2: The glass fiber reinforced resin molded article of Claim 1, which is injection molded using a molding material whose glass fibers have a number average aspect ratio of 5.5 to 14.