JPH03212445A - Molding resin composition - Google Patents

Abstract

PURPOSE:To provide the subject thermoplastic molding resin composition composed of a polybutylene terephthalate resin having a specified viscosity and a nylon 6 resin having a specified viscosity and having a remarkably excellent impact resistance without damage to excellent properties inherent in both the components. CONSTITUTION:A molding resin composition composed of (A) 50-70wt.% polybutylene terephthalate resin having 1.3-1.5 intrinsic viscosity in o- chlorophenol at 25 deg.C and (B) 50-30wt.% nylon 6 resin having 3.6-3.7 relative viscosity measured in 98wt.% H2SO4 at 25 deg.C using a polymer solution of 1g/100ml polymer concentration. Preferably, to 10-90wt.% above-mentioned composition, 10-50wt.% chopped strand glass fiber is added and, as necessary, a heat stabilizer, an antioxidant, a light stabilizer, a plasticizer, another material for improvement of impact resistance, etc., are added thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resin composition used as a molding material. More specifically, nylon 6 resin (hereinafter referred to as nylon 6) and polybutylene ethylene phthalate resin (hereinafter referred to as PBT)
It is written as ) A thermoplastic molding resin composition having excellent impact resistance.

(Conventional technology and its issues) Nylon 6 has excellent physical and chemical properties, so
In recent years, it has also been used as a molding material.

This is because nylon 6 resin has high mechanical strength, excellent abrasion resistance, chemical resistance, heat resistance, and relatively high electrical properties among thermoplastic resins, and has sufficient performance as an engineering plastic. Depends on what you're doing. However, on the other hand, there are cases where the amide group (-CONH-) has undesirable performance such as dimensional changes due to water absorption and a decrease in mechanical strength, which limits its marketability as a molding material. It was.

Further, PBT does not deteriorate its physical properties due to water absorption, and has excellent physical and chemical properties similar to nylon 6, and is widely used as a molding material. However, when exposed to hot water for a long time, the mechanical strength decreases significantly. For this reason, attempts have been made to mix nylon 6 and PBT in order to compensate for their shortcomings, but simply mixing them would significantly reduce their excellent performance, especially impact resistance, making it difficult to put them into practical use. That was impossible.

As a mixing method for preventing a decrease in mechanical strength due to simple mixing and compensating for the drawbacks of both, for example, Japanese Patent Application Laid-open No. 5
1-103191 and Japanese Patent Application Laid-Open No. 56-42645 propose a method of mixing at the polymerization stage, but the equipment is large-scale and mixing takes time, making it impractical.

(Means for Solving the Problem) The inventors mixed nylon 6 and PBT by simple melt mixing using an extruder or the like, thereby eliminating the drawbacks of both without impairing the excellent performance of both. As a result of intensive studies aimed at improving the impact resistance, it was found that this objective could only be met when a specific amount of nylon 6 with a specific viscosity and PBT with a specific viscosity were mixed uniformly, but it was found that the impact resistance was outstanding. It was discovered that an excellent composition can be obtained, leading to the present invention.

That is, the present invention provides a) PBT50 to 1.5 having an intrinsic viscosity of 1.3 to 1.5 as measured at 25°C in o-chlorophenol.
70% by weight and b) polymer concentration 1 g/l 00m
, the relative viscosity measured at 25°C in 98% H2s04 was 36
The present invention relates to a molding resin composition comprising 650 to 30% by weight of nylon in the range of .about.3.7.

The nylon 6 resin used in the present invention is obtained by ring-opening polymerization of ε-caprolactam, and has a relative viscosity of 3.6 to 3.7 measured at 25°C at a polymer concentration of 1 g/100 ml in 98% HSO2. If you convert this viscosity into a number average molecular weight, it is approximately 20,000 to 24.
,000. Those with a relative viscosity of less than 3.6 or more than 3.7 are undesirable because impact strength decreases.

The polybutylene terephthalate resin used in the present invention is a polyester of 1.4-butylene glycol and terephthalic acid or isophthalic acid, and has an intrinsic viscosity of 1.3 to 1.4 when measured at 25°C in 0-chlorophenol. It is in the range of 5. Those with an intrinsic viscosity of less than 1.3 or more than 1.5 are undesirable because impact strength decreases. Furthermore, even when mixing PBT and nylon 6 that meet the respective viscosity ranges, if the PBT and nylon 6 are outside the range of 50 to 70% by weight and 50 to 30% by weight, the impact strength of the composition will deteriorate. This is not desirable.

In addition, for the molding resin composition of the present invention, glass fibers, metal fibers, aramid fibers, ceramic fibers, cariwi scar titanate, carbon fibers, fibrous reinforcing agents such as asbestos, talc, calcium carbonate, mica, clay, Particulate reinforcing agents such as titanium oxide, aluminum oxide, glass flakes, milled fiber metal flakes, and metal powders may be incorporated. In particular, chopped strand type glass fibers are coated with the molding resin composition of the present invention.
By incorporating 10 to 50% by weight compared to 90% by weight, not only the mechanical strength and heat resistance temperature can be significantly improved, but also the water resistance performance can be further improved, achieving the purpose of the present invention. It is preferable to do so.

The molding resin composition of the present invention may further contain one or more additives such as heat stabilizers, oxidation stabilizers, light stabilizers, lubricants, pigments, flame retardants, plasticizers, and the like.

Furthermore, although the resin composition of the present invention has excellent impact resistance, for applications requiring even higher impact resistance, it is recommended to use known polyamide resins, thermoplastic polyester resins, and/or other resins. Any desired amount of effective impact modifier may be added.

The method for producing the molding resin composition of the present invention is not particularly limited, but preferably includes a method of mixing nylon 6 with PBT using a known melt mixer such as an extruder, kneader, or panburi mixer. It will be done.

(Example) Example I PBT (DURANEX XD478 manufactured by Polyplastics Co., Ltd., hereinafter referred to as PBT-XD478) 9 kg
and nylon 6 (Ube Nylon 6 manufactured by Ube Industries, Ltd.)
1022B, hereinafter referred to as nylon 6-1022B. )6
kg was mixed for 15 minutes at room temperature using a Henschel mixer. The resulting resin mixture was melt-kneaded at 240°C using a 40 mmφ single-screw extruder to form a pellet, which was then molded using a screw-type injection molding machine at 240°C to prepare a predetermined test piece.

For these specimens, the flexural modulus (sample thickness 3
．． 2mm5 Measurement temperature: 23°C, hereinafter referred to as FM. ) to JI
Izot impact strength (sample thickness 3
．． 2 mm, measurement temperature 23° C., with cutting notch, hereinafter referred to as Is. ) in JIS K7110, heat deformation temperature sample thickness 3.2 mm5 bending stress 4.6 kgr/c+t and 1 g, 6 kgf/cJ, no annealing, hereinafter referred to as HDT. ) was measured according to 5K7207.

The results obtained are shown in Table 1.

Example 2-3 PBT-XD478 2.5 kg, nylon 6102
2B2.5kg mixture and PBT-XD478 3
．． 25kg, nylon 6-1022 B 1.75k
A test piece was obtained by mixing, melting, and injection molding the mixture of g in the same manner as in Example 1. The physical properties of these test pieces were measured in the same manner as in Example 1.

The results obtained are shown in Table 1.

Comparative example 1-2 PBT-XD478 4kg, nylon 6102281
kg of the mixture, 2 kg of PBT-XD478, and 3 kg of nylon 6-10228 were mixed, melt-kneaded, and injection molded in the same manner as in Example 1 to obtain a test piece. The physical properties of these test pieces were measured in the same manner as in Example 1.

The results obtained are shown in Table 1.

Comparative Example 3-9 Several types of PBT3k manufactured by Polyplastics Co., Ltd. with different intrinsic viscosities measured at 25°C in ortho-chlorophenol
g and polymer concentration 1g/100m198%H2SO4
Several types of Ube Industries (Ube Industries) with different relative viscosities measured at 25℃
Comparisons were made with Example 1 using seven types of mixtures with 62 kg of Nimen Co., Ltd.

All of these mixtures were mixed, melt-kneaded, and injection molded in the same manner as in Example 1 to obtain test pieces.

The physical properties of these test pieces were measured in the same manner as in Example 1, and the obtained results and P
The viscosities of BT and nylon 6 are also shown in Table 1.

(Effects of the Invention) In general, when different types of polymers are mixed together, physical properties, particularly in impact resistance, are significantly deteriorated.

This is a major problem in polymer alloys. Even in PBT/nylon 6-based polymer alloy,
Improving impact resistance was a top priority.

However, the molding composition of the present invention has excellent impact resistance that more than compensates for this problem, and is extremely useful as a molding material.

Claims (1)

[Scope of Claims] a) 50 to 70% by weight of a polybutylene terephthalate resin having an intrinsic viscosity in the range of 1.3 to 1.5 measured at 25° C. in o-chlorophenol; and b) a polymer concentration of 1 g/100 ml. 98%H_2SO
A molding resin composition comprising 50 to 30% by weight of a nylon 6 resin having a relative viscosity in the range of 3.6 to 3.7 measured at 25°C in _4.