JPS5818944B2 - Fiber reinforced polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fiber-reinforced polyamide resin composition that can provide molded articles with improved weld strength.

Reinforced polyamide resin, especially polyamide resin reinforced with fibrous reinforcement, has strength, rigidity, and impact resistance.

Characteristic 1: Because it has excellent properties such as surface gloss, oil resistance, chemical resistance, heat resistance, and durability, it is used in large quantities as parts for automobiles, home appliances, machinery, etc.

Recently, there has been an increase in the number of cars, motorcycles, agricultural machinery, outboard motors, etc., especially from the perspective of energy conservation.

There is an increasing demand for lightweight vehicles, and there is a noticeable movement to replace conventional metal parts with fiber-reinforced polyamide resin, and in the near future the demand will be several times larger than the current level. (It is expected that this will happen.

However, in order to replace plastics in fields where metals have traditionally been used, the reality is that the reliability of the plastic material is required to be several times greater than in previous applications.

Fiber-reinforced polyamide resin is a polyamide resin that originally has excellent heat resistance and solvent resistance, and is reinforced with fibrous reinforcing materials such as glass fiber, making it significantly more reliable as a molding material. has a fatal drawback that the strength of the weld portion is poor.

In other words, fiber-reinforced polyamide resin suffers from insufficient fusion, orientation of the fibrous reinforcing material, and entrapment of air in areas where molten resin collides with each other (weld area), which inevitably occurs during the molding process. Since the strength of the welded portion is lower than that of the non-welded portion, there is a problem that the welded portion selectively causes destruction.

Therefore, in order to avoid the above-mentioned drawbacks, measures have been taken to design the mold so that no welds are formed in the molded product, or to move the welds to areas that are not important for the strength of the molded product. Depending on the shape and use of the molded product, the above measures may not be sufficient, and in any case, the current situation is that the uses of fiber-reinforced polyamide resins are severely limited.

Therefore, the present inventors conducted intensive studies to obtain a fiber-reinforced polyamide resin that can provide a molded product with improved weld strength. As a result, the present inventors added hydroquinone and/or butyl By allowing hydroxyanisole to coexist,
The inventors have discovered that the above object can be effectively achieved and have arrived at the present invention.

That is, the present invention provides polyamide resin with fibrous reinforcing materials 5 to 5.
The present invention provides a fiber-reinforced polyamide resin composition comprising 70% by weight of the present invention and 0.05 to 10% by weight of hydroquinone and/or butylhydroxyanisole.

Although the mechanism of the effect of improving the strength of the weld region in the composition of the present invention is not clear, it is presumed that hydroquinone or butylhydroxyanisole improves the fusion properties of the molten resin.

The polyamide resin used in the present invention is one whose main component is one or more of nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, or copolymers containing these as main components.

Examples of fibrous reinforcing materials that can be used in the present invention include glass fibers, carbon fibers, aromatic polyamide fibers, and various whiskers.

The present invention can also be applied to polyamide resins containing so-called fillers such as wollastenite, mica, talc, calcium carbonate, or silicic anhydride. Therefore, even if the strength of the weld region is improved by incorporating hydroquinone or butylhydroxyanisole of the present invention, it is unlikely to bring much benefit.

However, even greater effects can be obtained by applying the present invention to reinforced polyamide resins containing both these fillers and fibrous reinforcing materials.

The content of the fibrous reinforcing material in the fiber-reinforced polyamide resin composition of the present invention is 5 to 70% by weight, preferably 10 to 50% by weight.
selected from a range of weight %.

If it is less than 5% by weight, no significant improvement in strength can be expected;
If it exceeds % by weight, the strength will actually decrease and the moldability and surface appearance will be adversely affected, which is not preferable.

The content of no-hydroquinone and/or butylhydroxyanisole in the reinforced polyamide resin composition of the present invention is selected from the range of 0.05 to 10% by weight, particularly 0.1 to 6% by weight, and the content is 0.05 to 10% by weight, particularly 0.1 to 6% by weight. If it is less than .05% by weight, the effect of improving weld strength is small, and if it exceeds 10% by weight, no further improvement can be expected, and other physical properties are adversely affected, which is not preferable.

Note that there are no particular limitations on the means for preparing the composition of the present invention; for example, there is an existing method of adding hydroquinone and/or butylhydroxyanisole (additive) when melt-kneading the fibrous reinforcing material and the polyamide resin. A tri-blend of fiber-reinforced polyamide resin and additives,
Molding method and a method of making additive mask pellets using polyamide resin, reinforced polyamide resin, or a third component that is compatible with the reinforced polyamide resin, diluting them with reinforced polyamide resin, and molding. Can be adopted.

Furthermore, hydroquinone and/or butylhydroxyanisole can also be added during polymerization of the polyamide resin.

The fiber-reinforced polyamide resin composition of the present invention can be used for injection molding,
It can be applied to any molding method that involves a process in which molten resin is fused in a fluid state, such as blow molding or injection blow molding.

Generally, welds do not occur in extrusion molding, but it is applicable when a special die shape causes the flow of molten resin to split into two or more parts in the die, which are fused in the subsequent process to form a product. can.

In addition, in the secondary processing of molded products, methods such as spin welding, hot plate fusion, and ultrasonic bonding can be used to locally melt the fiber-reinforced polyamide resin and then press-bond it to join.

The composition of the present invention may contain other fillers, pigments,
Other additives such as flame retardants, stabilizers, mold release agents, and lubricants can be included.

The effects of the present invention will be specifically explained below using examples.

Example 1 Nylon 66 (Tojo CM3001G-30)' pellets 100 reinforced with 30% by weight of glass fiber (silane treated)
0.3 parts by weight of hydroquinone powder or butylhydroxyanisole powder was added to each part by weight, mixed well in a polyethylene bag, and subjected to injection molding.

The injection molding machine used was Meiki Seisakusho 5J-35B, cylinder temperature 280℃, mold temperature 80℃', screw rotation speed 8Orpm, injection pressure 260kg/crA, molding cycle injection time 10sec, cooling time. is 10
Weld test mold (thickness 1/8" OASTM
A test piece was molded using a mold that had the shape of a No. I dumbbell and had gates at both ends so that the molten resin would be fused at the center.

The test piece after molding was placed in a desiccator containing silica gel, and left to cool in a temperature-controlled room at 23°C for 24 hours or more.
Next, a bending test according to ASTM D790 was conducted.

That is, the distance between the spans was set to 501rL1rL, the test piece was set so that the weld position was located between the two lower support stands, and the fracture strength and fracture deflection were determined at a bending speed of 1 mm/min.

ASTM No. Danvenil and impact test pieces were molded under the same conditions except that the molding pressure was changed to approximately 600 kg/ca. The tensile test was performed using ASTM D63s, and the impact test was performed using ASTM
Measured according to TMD256.

Further, for comparison, 0M3001G-30 alone was tested in the same manner.

These results are shown in Table 1. As is clear from these results, the weld strength of the fiber-reinforced polyamide composition of the present invention is improved by about 40% compared to a general fiber-reinforced polyamide resin to which hydroquinone or butylhydroxyanisole is not added.

Example 2 10 parts by weight of hydroquinone or butylhydroxyanisole was added to 100 parts by weight of CM3001G-30 used in Example 1, and the mixture was thoroughly premixed, and then kneaded and blended using a 30 mm extruder to produce master pellets. Ta.

The cylinder temperature of the extruder was set at 280° C., the screw rotation speed was 7 Orpm, and the discharge amount was about 6 kg/hr.

After air-drying the master pellet at 70°C for 20 hrs, the master pellet and CM3001G-30 were blended and injection molded so that the addition rate of hydroquinone or butylhydroxyanisole was 0.1 to 1.0% by weight. , the weld strength of each test piece was measured.

The molding conditions and measurement conditions are exactly the same as in Example 1.

The results are shown in Table 2. As can be seen from the comparison with Example 1,
Even when the mask pellet method is adopted as the method of adding hydroquinone or butylhydroxyanisole, the same effects as the triblend method can be obtained.

Furthermore, when hydroquinone or butylhydroxyanisole is added at 0.1% by weight, the weld strength increases by about 20%, and as the addition rate increases, the weld strength increases.

・Example 3 Nylon 6 reinforced with 45% by weight of glass fiber (silane treated) (Toshi ■CMI O11G-45>Pellet 100
Hydroquinone powder was thoroughly mixed with the parts by weight and injection molded.

In preparing the test piece, the conditions different from those in Example 1 were that the cylinder temperature was 260°C and the molding pressure was 480 kg/crt for the weld test heather! , 850 kg/crr for tensile and impact test pieces
Molding and measurement were performed under the same conditions except that t was used.

The results are shown in Table 3.

In addition, CMlollG- which does not contain hydroquinone
The measurement results for No. 45 are also shown in Table 3.

The effects of the present invention are also observed in nylon 6-based reinforced polyamide resin.

Claims (1)

[Claims] 1 Fiber-reinforced polyamide resin composition comprising polyamide resin mixed with 5-70% by weight of fibrous reinforcing material and 0.05-10% by weight of hydroquinone and/or butylhydroxyanisole.