JP2602162B2 - Polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition, and more particularly to a new resin composition capable of alloying a polyamide resin, a resin waste material which has recently become a problem, with a thermoplastic resin. .

[0002]

2. Description of the Related Art Polyamide resin is the most representative engineering plastic, and has mechanical strength, impact resistance,
Because of its excellent heat resistance and chemical resistance and good moldability, it is also used as many mechanical parts such as gears, rolls, and sliding plates. This polyamide resin is obtained by casting ε-caprolactam into a mold and performing anionic polymerization. When a plate or a round bar made of the cast polyamide resin material is machined, a large amount of processing waste is generated. But,
Processing waste of cast polyamide resin is high molecular weight, high crystallization,
Because of its high melting point, even if it is pelletized again by the extruder and it is to be reused, the load on the extruder is large and the extruded amount needs to be reduced, and the productivity is extremely poor. For this reason, most of the processing waste of the cast polyamide resin has been discarded as industrial waste. In order to improve this, a method has been proposed in which a lubricant such as calcium stearate or zinc stearate or a low-viscosity polyamide resin is added to the processing waste of the cast polyamide resin to lower the viscosity and extrusion is performed.

[0003]

However, even if a lubricant such as calcium stearate is added to the processing waste of the cast polyamide resin to lower the viscosity, the addition of a large amount deteriorates the biteability into the screw. Therefore, only a small amount could be added, and as a result, the load on the extruder was large and the moldability was significantly poor. Further, the low-viscosity polyamide resin has an advantage that it can be added to the cast polyamide resin at an arbitrary ratio, but the effect is small and unsatisfactory when the amount is small. An object of the present invention is to improve such a problem, and an object of the present invention is to provide a polyamide resin composition that can be sufficiently reused by efficiently using the processing waste of the cast polyamide resin.

[0004]

That is, the feature of the present invention is that the melt flow rate at 240 ° C. per 10 minutes is used.
Processing waste of cast polyamide resin with zero rate 20
Thermoplastic resin 1 having a melting point or softening point lower than the melting point of the cast polyamide resin at
The polyamide resin composition contains 2 to 77% by weight and 3 to 15% by weight of a compatibilizer. The polyamide resin composition described in the present invention comprises at least three components: a cast polyamide resin, a thermoplastic resin having a melting point lower than the melting point of the cast polyamide resin or a softening point lower than the melting point, and a compatibilizer. It includes those obtained by mixing, or the mixture is melt-kneaded using an extruder to form a polymer alloy into pellets, or the pellets are formed into a molded product by injection molding.

Hereinafter, the present invention will be described in more detail. The above cast polyamide resin is a substantially anhydrous ω-lactam having five or more ring members, and is obtained by casting 2-pyrrolidone, ε-caprolactam, ω-capryloractam, etc. into a mold and anion-polymerizing the same. It is the obtained polyamide resin. This production method is described in, for example, Japanese Examined Patent Publication No. 50-9.
No. 026 and Japanese Patent Publication No. 51-1277. The cast polyamide resin obtained by this method has a higher molecular weight than the polyamide resin obtained by another polymerization method because it is sufficiently polymerized in the mold, and since each molecule is also entangled, High melt viscosity. For this reason, the cast polyamide resin has a zero melt flow rate at 240 ° C. for 10 minutes. The added amount of the cast polyamide resin is 20 to 85% by weight.
If the amount is less than 0% by weight, the inherent heat resistance, high strength and high modulus of the cast polyamide resin do not appear effectively.
If it exceeds 5% by weight, the load on the extruder increases, and it is necessary to reduce the amount of extrusion per unit time.

The thermoplastic resin is a polypropylene having a lower melting point (220 to 250 ° C.) than the cast polyamide resin.
These are ABS, polystyrene, and AS having a softening point lower than the melting point of polyethylene or cast polyamide resin, and two or more of these can be used in combination. Further, it is also possible to use a polymer alloy having a softening point lower than the melting point of the cast polyamide resin or a polymer alloy having a melting point lower than that of the cast polyamide resin in which the cast polyamide resin and the polymer alloy are used. It is important that they are compatibilized by a compatibilizer and have a microphase-separated structure. That is, it is considered that the thermoplastic resins in the microphase-separated structure, which are not uniformly mixed with each other at the molecular level, significantly contribute to lowering the load (torque) on the extruder.

Further, the viscosity of the thermoplastic resin is 240
0.1g melt flow rate per 10 minutes at ° C
A time of / 10 minutes or more is preferable because the fluidity is high and the load on the extruder is small. Ultrahigh molecular weight polyethylene and ultrahigh molecular weight polypropylene cannot be used because the flowability is extremely poor and the load on the extruder increases. The addition amount of the thermoplastic resin is 12 to 77% by weight, and 12% by weight.
If it is less than 70%, the load on the extruder cannot be sufficiently reduced, and if it exceeds 77% by weight, the inherent heat resistance, high strength and high elastic modulus of the cast polyamide resin will not be exhibited.

Further, the compatibilizer used in the present invention has a functional group which reacts with the amino group at the terminal of the polyamide, for example, a carboxylic acid group, a carboxylic anhydride group, or an epoxy group. A polymer having good compatibility with the resin is chemically bonded. For example, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer, maleic anhydride-modified ABS, maleic anhydride-modified resin, acid-modified acryl-methyl It is a methacrylate graft copolymer, an acid-modified acrylic-styrene graft copolymer, an epoxy-modified polystyrene-methyl methacrylate graft copolymer, or the like, and may be used in combination of two or more in accordance with the thermoplastic resin used. . The modified maleic anhydride polypropylene is used as a compatibilizer between the cast polyamide resin and the polypropylene. As the thermoplastic resin, polyethylene, ABS, polystyrene, and AS are used.
It has no effect when used with. On the other hand, the maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer is used as a compatibilizer between a cast polyamide resin and a thermoplastic resin such as polypropylene, polyethylene and polystyrene. The maleic anhydride-modified ABS is made of cast polyamide resin and thermoplastic resin.
Used as a compatibilizer with BS and AS.

The amount of the compatibilizer added is 3 to 15% by weight,
Preferably it is 5 to 10% by weight. If the amount is less than 3% by weight, sufficient compatibilization is not performed irrespective of the degree of conversion of the acid, and if it exceeds 15% by weight, the degree of conversion of the acid is high, and gelation may occur during melt-kneading. Not only that, the properties of the compatibilizer affect the properties of the entire polymer alloy. The viscosity of the compatibilizer is not particularly limited as long as it can be melt-kneaded below the melting point of the cast polyamide resin, but is preferably 0.1 to 100 g / 10 minutes at 240 ° C. at a melt flow rate per 10 minutes. The amount of maleic anhydride in the compatibilizer is 0.1 to 10% by weight. If the amount is less than 0.1% by weight, the number of reaction points with the polyamide resin is too small, so that the compatibilizing ability is poor. On the other hand, if it exceeds 10% by weight, the polyamide resin gels and the load on the extruder increases, or the quality of the resin composition is impaired.

The temperature at which the above components are melt-kneaded is usually from 220 to 300 ° C. When the temperature decreases, the load on the extruder increases, and it is necessary to reduce the amount of extrusion per unit time . On the other hand, when the temperature increases, the obtained resin composition is colored. Melt kneading is performed using a melt kneader such as a single screw or twin screw extruder. In the resin composition of the present invention, in addition to the above three components, other additives such as a dye / pigment, a nucleating agent, a plasticizer, a lubricant, an antioxidant, an ultraviolet absorber, a flame retardant, an antistatic agent, and a fiber reinforcing material. Can be added as needed.

[0011]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 7 and Comparative Examples 1 to 5 After the compositions shown in Table 1 were previously dried in an oven at 90 ° C. for 5 hours, a single-screw extruder set at 240 ° C. (trade name:
Using a Labo Plast Mill D20-20 (manufactured by Toyo Seiki Co., Ltd.), the cylinder temperature was 240 ° C., and the screw rotation speed was 20.
The torque was measured under the condition of rpm. Table 1 shows the results.

Further, the same compound as described above is melt-kneaded with a twin screw extruder (trade name: PCM45 manufactured by Ikegai Iron Works Co., Ltd.) set at 240 ° C. to produce pellets, and the pellets are heated at a cylinder temperature of 240 ° C. Using a C injection molding machine (trade name: SG25, manufactured by Sumitomo Heavy Industries, Ltd.), injection molding was performed on a mold set at a mold temperature of 60 ° C. to produce a molded product (test piece). The appearance (surface state) and elongation at break of tensile strength of the obtained molded article were measured in accordance with JIS K7113. Table 1 shows the results.

[0013]

[Table 1]

As is clear from the results, the resin compositions of the examples have good physical properties in appearance and elongation, and can be extruded with a small torque to form pellets.

[0015]

As described above, in the polyamide resin composition of the present invention, the melt temperature per 240 minutes at 10 minutes is used.
Low rate is zero, which is lower than ordinary polyamide resin
Reduced processing waste of cast polyamide resin with high melt viscosity
Both a thermoplastic resin having a melting point or a softening point lower than the melting point of the cast polyamide resin and a compatibilizer are added, and the compatibilizer is present between the cast polyamide resin and the thermoplastic resin. By combining these three components, the three components are uniformly melt-kneaded to greatly improve the extrudability, and the production of re-pellets becomes feasible, thereby contributing to the reuse of the cast polyamide resin, and from the pellets. The obtained molded article not only has an appearance but also has an effect of maintaining sufficient physical properties.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C08L 23:26) (C08L 101/00 77:00 23:26) Examiner Seiji Sakano (56) References JP-A-60-110740 (JP, A) JP-A-1-294748 (JP, A)

Claims (3)

(57) [Claims] 1. Melt per 10 minutes at 240 ° C.
Processing waste of cast polyamide resin with zero low rate 2
0 to 85% by weight, at least 12 to 77% by weight of a thermoplastic resin having a melting point or softening point lower than the melting point of the cast polyamide resin, and 3 to 15% by weight of a compatibilizer. Polyamide resin composition. 2. The polyamide resin composition according to claim 1, wherein the compatibilizer is an acid-modified resin. 3. An acid-modified resin comprising a maleic anhydride-modified polyethylene, a maleic anhydride-modified polypropylene, and a maleic anhydride-modified styrene. ethylene. Butylene. The polyamide resin composition according to claim 2, which is a modified maleic anhydride resin selected from a styrene block copolymer and a modified maleic anhydride ABS.