JPH0254854B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyamide resin composition.
More specifically, the present invention relates to a polyamide resin composition that has significantly improved impact resistance without substantially impairing the desirable properties inherent in polyamide resins. Polyamide resins generally have excellent heat resistance, chemical resistance, abrasion resistance, and bending elasticity, so they are widely used as engineering resins for various mechanical parts and automobile parts. It has the disadvantage of not being satisfactory in terms of impact resistance. In order to compensate for these drawbacks, various proposals have been made to modify polyamide resins by blending them with other types of resins. For example, a blend of ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid metal salt (-α,β-unsaturated carboxylic acid ester) copolymer resin [ionomer resin] with polyamide resin (Special Publication No. 54-4743, No. 55-44108
Although the impact resistance can be improved without substantially impairing desirable properties such as heat resistance and bending elasticity, the improvement effect is not fully satisfactory. On the other hand, polyamide resin has ethylene-
A blend of an alkyl (meth)acrylate copolymer with a maleic anhydride graft modified product can significantly improve impact resistance without substantially impairing the desirable properties inherent in these polyamide resins. The present inventors have discovered. Therefore, the present invention relates to a polyamide resin composition, which comprises 60 to 95 parts by weight of a polyamide resin and 40 parts by weight of a maleic anhydride graft modified ethylene-alkyl (meth)acrylate copolymer. ~5 parts by weight. Additionally, polyamide resins are often used by filling them with glass fibers to increase their mechanical strength, but in this case there is a significant drop in impact resistance. Although improvement has also become a major issue, the present invention also solves this issue. Therefore, the present invention also relates to a polyamide resin composition in which the blend is further filled with glass fibers. Examples of the polyamide resin that is the main component of the composition include nylon-6, nylon-66, nylon-610, nylon-11, nylon-12, and nylon-14. The ethylene-alkyl (meth)acrylate copolymer as the base polymer of the graft modified product is
It is obtained by radical copolymerization of ethylene and alkyl acrylate or alkyl methacrylate, preferably their methyl ester or ethyl ester, more preferably their ethyl ester, using a high-pressure polyethylene production apparatus. The copolymerization ratio of alkyl (meth)acrylate in this copolymer is 8 to 20 mol%. If the copolymerization ratio of alkyl (meth)acrylate is higher than this, it will not only be difficult to produce the copolymer;
The flexural rigidity and heat resistance of the grafted modified product are extremely reduced, and the physical properties when made into a composition are significantly impaired. The sexual improvement effect decreases. The melt index of this base polymer [ASTM D-1238 (190°C, 2160 g)] is generally about 0.5 to 300 dg/min, preferably about 0.5 to 300 dg/min, although it varies depending on the melt viscosity of the polyamide resin composition used. is preferably about 4 to 200 dg/min,
It is generally difficult to produce copolymers outside this range. Furthermore, even if it can be produced, if a copolymer with a melt index lower than this is used, the melt index will decrease when graft-modified with maleic anhydride, leading to poor dispersion when blended with polyamide resin. On the other hand, if a material with a melt index higher than this is used, the effect of improving the impact resistance of the composition will decrease. The amount of maleic anhydride grafted onto the ethylene-alkyl (meth)acrylate copolymer is based on the base polymer.
It ranges from 0.1 to 8% by weight, preferably from 0.3 to 5% by weight. If the amount of grafting is less than this, the desired effect of improving the impact resistance cannot be obtained, and on the other hand, even if the amount of grafting is more than this, the effect of improving the impact resistance of the composition will not be obtained any more. The fluidity of the graft modified product decreases, leading to poor dispersion when it is made into a composition. The method of grafting is not particularly limited, but is generally carried out by reacting an ethylene-alkyl (meth)acrylate copolymer with maleic anhydride in the presence of a free radical-generating compound, such as tert-butyl peroctoate. Industrially, it is economical to carry out the reaction in an extruder at a temperature of about 120 to 250°C. The composition comprises 60 to 95 parts by weight of polyamide resin, preferably 70 to 90 parts by weight of the graft modified product.
It is prepared by blending in a proportion of 40 to 5 parts by weight, preferably 30 to 10 parts by weight. If the proportion of the polyamide resin is lower than this, the desirable properties inherent to the polyamide resin will not be exhibited, and conversely, if the proportion is higher than this, the composition will not have high impact resistance. The impact resistance improvement effect of such a blend body is
It is also fully demonstrated in glass fiber filling, which is one of the main uses for polyamide resins. Glass fibers are generally surface-treated with a silane coupling agent such as aminosilane or vinylsilane, and have a fiber length of about 2 to 10 mm and a fiber diameter of about 5 to 15 μm, at a ratio of 5 to 60 parts by weight per 100 parts by weight of the blend. used in When used in a proportion of 5 parts by weight or more, an effect of reinforcing mechanical properties can be expected;
If it is used in a proportion of 60 parts by weight or more, the impact resistance will be greatly reduced. The composition is prepared by adding various additives such as an inorganic filler such as calcium carbonate, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, and a pigment as necessary. This is done by dry blending or melt blending each component. In the case of dry blending, each component is uniformly melt-mixed at the stage of plasticization in a molding machine, and in the case of melt blending, various mixers such as a single-screw or twin-screw extruder, a Banbury mixer, Melt mixing may be performed using a roll, a kneader, or the like. As described above, the polyamide resin composition according to the present invention significantly improves impact resistance without substantially impairing the desirable properties inherent in polyamide resins, such as heat resistance and bending elasticity. By effectively utilizing
It can be used in various molding technology fields such as press molding, blow molding, and profile extrusion molding. For example, when this polyamide resin composition is molded into wheels for roller skates, it has excellent impact resistance at low temperatures, so even if the wheels are subjected to impact in winter, they are unlikely to crack. It's not easy. Next, the present invention will be explained with reference to examples. Example 1 Nylon-6 (Toray product Amiran CM-1017C)
80 parts (by weight, same below) and ethylene-ethyl acrylate copolymer (ethyl acrylate content
20 parts of maleic anhydride graft modified product (grafting amount: 2% by weight) of 8.5 mol%, melt index 5dg/min) were melt-kneaded at 250°C using a twin-screw extruder (30mm diameter, coaxial rotation), and kneaded. A test piece specified by the following test method was produced using the polyamide resin composition obtained by injection molding. Regarding this test piece, Izot impact strength (specimen thickness 5 mm; compliant with ASTM D-256, V-notched, -20℃ and -30℃), flexural strength modulus (specimen thickness 2 mm; compliant with ASTM D-790) ) and heat distortion temperature (specimen thickness 3 mm; ASTM D-648 compliant,
0.45MPa) were measured respectively. Example 2 In Example 1, another ethylene-ethyl acrylate copolymer (ethyl acrylate content 15.7 mol%, melt index
7 dg/min) was used. Example 3 In Example 1, another ethylene-ethyl acrylate copolymer (ethyl acrylate content 13.1 mol%, melt index
25 dg/min) was used. Example 4 In Example 1, the grafting amount of maleic anhydride was changed to 0.5% by weight. Example 5 In Example 1, the amount of maleic anhydride grafted was changed to 4% by weight. Example 6 In Example 1, another ethylene-ethyl acrylate copolymer (ethyl acrylate content 9.4 mol%, melt index
200 dg/min) was used, and the amount of maleic anhydride grafted was changed to 3% by weight. Example 7 A composition was prepared in Example 1 except that 90 parts of nylon-6 and 10 parts of the maleic anhydride graft modified product were used. Example 8 A composition was prepared in Example 1 except that nylon-6 was changed to 70 parts and the maleic anhydride graft modified product was changed to 30 parts. Example 9 In Example 1, a composition was prepared by further filling the blended body with 10 parts of glass fiber (manufactured by Nitto Boseki, diameter 13 μm, length 6 mm). Comparative Example 1 In Example 1, no maleic anhydride graft modification product was used. Comparative Example 2 In Example 1, the base polymer of ethylene-ethyl acrylate copolymer was used instead of the maleic anhydride graft modified product. Comparative Example 3 In Example 1, instead of the maleic anhydride graft modified product, an ester copolymer resin, which is said to have the greatest effect on improving nylon impact among ionomer resins, specifically ethylene-methacrylic acid-isobutyl acrylate (93.6: 3.8: 2.6 mol%) copolymer resin (melt index 35 dg/min) with 70% Zn
An ionomer resin ionized with ions was used. Comparative Example 4 In Comparative Example 3, a composition was prepared by changing the amount of nylon-6 to 70 parts and the amount of the ionomer resin to 30 parts. Comparative Example 5 In Comparative Example 3, instead of the ionomer resin, a copolymer resin of which Zn was not ionized was used. Comparative Example 6 In Comparative Example 5, copolymer resins (10 dg/min) having the same copolymerization composition but different melt index were used. Comparative Example 7 In Comparative Example 5, a copolymer resin grafted with 2% by weight of maleic anhydride was used. Comparative Example 8 In Comparative Example 6, a copolymer resin grafted with 1% by weight of maleic anhydride was used. Comparative Example 9 A composition was prepared in Comparative Example 8 except that the amount of nylon-6 was changed to 70 parts and the amount of maleic anhydride graft-modified copolymer resin was changed to 30 parts. Comparative Example 10 In Comparative Example 3, 10 parts of the glass fiber used in Example 9 was further filled to prepare a composition. The measurement results of physical property values in each of the above Examples and Comparative Examples are shown in the following table.

【table】

[Table] Example 10 A composition was prepared in Example 1 except that nylon-6 was changed to 67 parts and the maleic anhydride graft modified product was changed to 33 parts, and a test piece was prepared. The Izod impact strength of this test piece at -20°C was NB. Comparative Example 11 In Example 10, a maleic anhydride graft modified product of ethylene-1-butene copolymer (1-butene content 10 mol%, melt index 18 dg/min) was used instead of the maleic anhydride graft modified product. (graft amount: 2% by weight) was used. The Izod impact strength of the prepared test piece at -20°C was 245 J/m. Comparative Example 12 In Example 10, instead of the maleic anhydride graft modified product, a maleic anhydride graft modified product (grafted 2% by weight) was used. Fuming was observed during melt-kneading with polyamide resin. The prepared test piece was yellowed and had an Izod impact strength of 63 J/m at -20°C.

Claims (1)

[Scope of Claims] 1 Maleic anhydride graft modified product of ethylene-alkyl (meth)acrylate copolymer containing 60 to 95 parts by weight of polyamide resin and 8 to 20 mol% of alkyl (meth)acrylate 40 -5 parts by weight of a polyamide resin composition. 2. The polyamide resin composition according to claim 1, which uses a graft modified product obtained by graft copolymerizing 0.1 to 8% by weight of maleic anhydride to an ethylene-alkyl (meth)acrylate copolymer. 3 Blend of 60 to 95 parts by weight of polyamide resin and 40 to 5 parts by weight of a maleic anhydride graft modified product of ethylene-alkyl (meth)acrylate copolymer having an alkyl (meth)acrylate content of 8 to 20 mol% A polyamide resin composition whose body is further filled with glass fibers. 4. The polyamide resin composition according to claim 3, which is filled with 5 to 60 parts by weight of glass fiber per 100 parts by weight of the blend.