JPH05345852A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To provide a polyamide resin composition comprising polyamide, PP, modified PP, and specific thiourethane resins in a specific ratio, excellent in impact resistance, heat resistance and low water absorption, and useful for automotive parts, etc. CONSTITUTION:This resin composition comprises (A) 40-90wt.% of a polyamide resin such as nylon 6, (B) 8-58wt,% of PP resin, (C) 1-20wt.% of a modified PP resin modified with an unsaturated carboxylic acid such as acrylic acid, etc., and (D) 1-30wt.% of a thiourethane resin comprising repeating units of the formula (Ar is phenylene) and having a number-average mol.wt. of >=3500.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyamide resin composition having excellent impact resistance, low water absorption and heat resistance, which is particularly suitable for automobile parts, electric / electronic device parts and the like. Regarding

[0002]

2. Description of the Related Art Polyamide resins are widely used in various fields as synthetic fibers, films and various molding materials because of their excellent physical and chemical properties.
However, on the other hand, since it has a low impact resistance and has water absorbency, it has a drawback that the dimensional change of the molded product and the deterioration of mechanical strength occur over time. As a method for improving this, there has been conventionally proposed a composition in which a modified polyolefin obtained by grafting an olefin polymer and an unsaturated carboxylic acid or a derivative thereof onto a polyamide resin is blended (for example, JP-B-42-12546, (Japanese Patent Publication No. 45-30945, Japanese Patent Publication No. 50-7636, etc.).

[0003]

However, even with the above composition, there is a problem that the impact resistance is still insufficient, and the market as a molding material may be limited in some cases. From the above, it is an object of the present invention to provide a composition having excellent impact resistance and low water absorption without deteriorating the excellent properties originally possessed by the polyamide resin.

[0004]

As a result of intensive studies, the present inventors have found that the above object can be achieved by blending a specific linear polymer compound, and based on this finding, The present invention has been completed. That is, the present invention is (A) polyamide resin 40 to 90% by weight,
(B) a polypropylene resin 8-58 wt%, (C) a modified polypropylene resin of 1 to 20 wt% and (D) formula _{-CO-NH-CH 2 -Ar-} CH 2 -NH-CO-S-CH 2 CH 2 1 to 30% by weight of a thiourethane resin having a repeating unit represented by -S-CH ₂ CH ₂ -S- (wherein Ar represents a phenylene group) and having a number average molecular weight of at least 3,500.
The present invention provides a polyamide resin composition comprising Hereinafter, the present invention will be specifically described.

The polyamide resin used in the present invention is a linear polymer compound having an amide bond (-CONH-), and is roughly classified into polyamides and cyclic lactams obtained by polycondensing dibasic acids and diamines. Polyamides obtained by self-polycondensing amino acids are known. Typical examples of the former are polycondensates of hexamethylenediamine and adipic acid (nylon 66), polycondensates of hexamethylenediamine and sebacic acid (nylon 610), and polycondensates of hexamethylenediamine and dodecanoic acid. (Nylon 612), polycondensate of hexamethylenediamine and terephthalic acid (nylon 6T), polycondensate of xylylenediamine and adipic acid (XD6 nylon), and polycondensate of xylylenediamine and sebacic acid (XD10 Nylon).

Further, as typical examples of the latter, a self-polycondensate of caprolactam (nylon 6), a self-polycondensate of 10-aminoundecanoic acid (nylon 11) and a self-polycondensate of laurinlactam (nylon 12) are mentioned. Can be mentioned. These polyamide resins may be used alone or in combination of two or more. The degree of polymerization of these polyamide resins is not particularly limited, but generally has a relative viscosity of 2.0 to 5.0, particularly 2.5 to 4.
5 is preferable.

The composition ratio of the polyamide resin in the composition of the present invention is 40 to 90% by weight, preferably 50.
~ 80% by weight. Polyamide resin composition ratio is 40
If it is less than wt%, the heat resistance is not sufficient. On the other hand, when it exceeds 90% by weight, the effect of improving water absorption is lowered.

The polypropylene resin used in the present invention is a homopolymer of propylene and a copolymer of propylene and other α-olefin. Here, the copolymer includes a random or block copolymer. Examples of other α-olefins include ethylene and butene-1
And so on. Further, these polypropylene resins can be used in combination of two or more kinds. Further, the resin contains a small amount of an olefinic copolymer rubber such as ethylene-propylene rubber, ethylene-butene rubber, propylene-butene rubber, ethylene-propylene-diene terpolymer rubber. Good. The molecular weight of the polypropylene resin is not particularly limited,
Usually, those having an MFR of 1 to 50 g / 10 minutes are suitable.

The composition ratio of the polypropylene resin in the composition of the present invention is 8 to 58% by weight, preferably 1
It is 0 to 40% by weight. When the composition ratio of the polypropylene resin is less than 8%, low water absorption cannot be imparted.
On the other hand, if it exceeds 58% by weight, the heat resistance decreases.

The modified polypropylene resin used in the present invention is the above polypropylene resin grafted with an unsaturated carboxylic acid or its derivative or a monomer having an epoxy group. The graft amount of the unsaturated carboxylic acid or its derivative is preferably 0.01 to 10% by weight, and particularly preferably 0.1 to 5% by weight. When the graft amount of the unsaturated carboxylic acid or its derivative is less than the above range, the effect of improving the compatibility and physical properties of the composition cannot be obtained. Examples of the unsaturated carboxylic acid or its derivative include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and the like, or acid anhydrides thereof, ester metal salts and the like.

For the production of the modified polypropylene resin used in the present invention, various known methods can be adopted. For example, a method in which an unsaturated carboxylic acid or its derivative and a reaction initiator, for example, an organic peroxide such as di-t-butylperoxide are added to a polypropylene resin and dry-blended in advance and then melt kneading, or the polypropylene resin is used as a solvent And an unsaturated carboxylic acid or its derivative and a reaction initiator are added thereto to carry out a reaction.

The composition ratio of the modified polypropylene resin in the composition of the present invention is 1 to 20% by weight, preferably 3 to 20% by weight. When the composition ratio of the modified polypropylene resin is less than 1% by weight, the effect of improving compatibility is poor. On the other hand, if it exceeds 20% by weight, the melt viscosity may increase and molding may not be possible in some cases.

Further, the thiourethane resin used in the present invention has the formula --CO--NH--CH ₂ --Ar--CH ₂ --NH--CO--S--CH ₂ CH ₂ --S--CH ₂ CH ₂ --S-- (Wherein Ar represents a phenylene group) is a resin having a thiourethane bond (NH—CO—S) in the skeleton. As an example of the resin, for example, xylylene diisocyanate and dimercaptoethyl sulfide are easily produced by polyaddition reaction using amines such as diethylamine, triethylamine, cyclohexylamine, or tin compounds such as dibutyltin laurate as a catalyst. can do. The degree of polymerization of the resin is at least 3,500 in number average molecular weight, preferably 6,000.
That is all. If the number average molecular weight is less than 3,500, the impact resistance decreases.

The composition ratio of the compound in the composition of the present invention is 1 to 30% by weight, preferably 5 to 20% by weight. When the composition ratio of the compound is less than 1% by weight, impact resistance is poor, while when it exceeds 30% by weight, heat resistance is deteriorated.

To prepare the composition of the present invention, a mixer such as a Henschel mixer, a tumbler, a kneader, a Banbury mixer and a screw type extruder generally used in the art may be used. In order to obtain a more uniform composition, two or more of these mixers may be used in combination. The temperature during melt kneading is generally 150 to
It is 350 ° C., and particularly preferably 180 to 300 ° C.

In the composition of the present invention, if desired, various additives usually used, for example, lubricants, antioxidants, ultraviolet absorbers, antistatic agents, mold release agents, plasticizers, dyes, pigments, various kinds are added. Fillers and the like can be added. Further, the composition of the present invention can be molded into a desired shape using a generally used extrusion molding machine, injection molding machine, compression molding machine or the like.

[0017]

EXAMPLES The present invention will now be described in more detail by way of examples. The Izod impact strength is ASTM D63
According to No. 8, it was measured with a notch and a temperature of 23 ° C. Also,
Heat distortion temperature and water absorption are according to ASTM D64
8 and ASTM D570.

As the polyamide resin, nylon 66 having a relative viscosity of 2.7 and nylon 6 having a relative viscosity of 2.6 were used. As the polypropylene resin, polypropylene having an MFR of 16 was used.
In addition, as a modified polypropylene resin, MFR (230
Graft-modified polypropylene was used in which 0.35% by weight of maleic anhydride was added to isotactic polypropylene (in ° C) of 1.0 g / 10 minutes.

Further, the thiourethane resin was manufactured by the following method. To a reactor having a capacity of 10 l, toluene 3 l, m-
Xylylene diisocyanate 500 g, dimercaptoethyl sulfide 410 g and dodecyl mercaptan 1
g was added and dissolved. After dissolution, while keeping the solution cooled at 5 ° C., 3 g of diethylamine was gradually added dropwise, and then,
The reaction was carried out at 50 ° C for 6 hours. After the reaction was completed, the product was separated by filtration and further dried by a vacuum dryer for 12 hours to obtain a thiourethane resin powder (hereinafter referred to as TU-1). The number average molecular weight determined by GPC using PMMA of the obtained powder as a standard was 38,000. Dodecyl mercaptan 5
The number average molecular weights of the resins (hereinafter referred to as TU-2 and TU-3, respectively) obtained in the same manner as described above except that g and 10 g are 6,700 and 2, respectively.
It was 900.

Examples 1 to 8 and Comparative Examples 1 to 4 Compositions and blending ratios shown in Table 1 were used to melt-knead at a temperature of 270 ° C. using a twin-screw extruder (diameter 30 mm) to obtain compositions. Was manufactured. A test piece was prepared from each of the obtained compositions, and the Izod impact strength, heat distortion temperature and water absorption were measured. The results are shown in Table 1.

[0021]

[Table 1]

[0022]

EFFECT OF THE INVENTION Since the polyamide resin composition of the present invention has an excellent balance between impact resistance and heat resistance and has low water absorption, it is used in the field of automobile parts, electric / electronic equipment parts and other industrial parts. Is promising in.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location C08L 75/00 NGG 8620-4J NGJ 8620-4J (72) Inventor Kenji Fujitani 3 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture No. 2 Sho Kawasaki Resin Research Laboratory (72) Inventor Satoshi Maruyama No. 3 Chidori-cho, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Sho Sho Kawasaki Resin Research Laboratory

Claims (1)

[Claims] 1. (A) Polyamide resin 40 to 90% by weight, (B) Polypropylene resin 8 to 58% by weight,
(C) a modified polypropylene resin of 1 to 20 wt% and (D) formula _{-CO-NH-CH 2 -Ar-} CH 2 -NH-CO-S-CH 2 CH 2 -S-CH 2 CH 2 -S- ( In the formula, Ar represents a phenylene group), and a thiourethane resin having a number average molecular weight of at least 3,500 1 to 30% by weight
A polyamide resin composition comprising: