JP2794943B2 - Polyamide resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic resin composition comprising a polyamide resin and a polypropylene resin, which is particularly excellent in coatability.

(Problems to be Solved by the Prior Art and the Invention) Generally, it has been reported in Japanese Patent Publication No. 50-7636 that a polyamide resin and a polypropylene resin are well compatible by modifying the polypropylene resin. The paintability of the product is such that non-polar polypropylene resin is blended with the non-polar polypropylene resin, so that partially incompatible polypropylene precipitates on the surface of the molded product, and it is necessary to treat the surface with trichlorethylene or primer treatment before baking coating .

This means that the properties of polyamide resin, which can be easily baked and painted only by degreasing, are lost, and the properties obtained by blending an appropriate amount of polyamide resin with polyamide resin (low specific gravity, low water absorption, improved calcium chloride resistance, etc.) ) Will be greatly reduced.

The present invention is a thermoplastic resin composition comprising a polyamide and a polypropylene, a coating property similar to a polyamide resin, mechanical strength, while maintaining the heat resistance, a composition having improved properties such as physical property deterioration and dimensional change due to moisture absorption of the polyamide. It is intended to provide.

(Means for Solving the Problems) The present inventors have conducted intensive studies to achieve the above object, and as a result, by modifying a specific polypropylene, it is possible to maintain the coating property, rigidity, heat resistance, etc. Calcium properties, found a thermoplastic resin composition with excellent impact resistance,
The present invention has been reached.

That is, the present invention is obtained by graft copolymerizing 0.05 to 2.0 parts by weight of an unsaturated carboxylic acid or a derivative thereof to 100 parts by weight of (a) a polyamide resin, (b) a crystalline polypropylene resin, and (c) a crystalline polypropylene resin. A modified polypropylene resin, wherein (a) / [(b)
+ (C)] = 80/20 to 70/30 (weight ratio) (b) / (c) =
The melt flow rate (MFR) at 230 ° C. and 2160 g of the blend of the component (b) and the component (c) is 2 to 35 g / 10 minutes. It is a polyamide resin composition.

As the (a) polyamide resin used in the present invention, hexamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2.2.4- or 2.
4,4-trimethylhexamethylenediamine, 1,3-
Or 1,4-bis (aminomethyl) cyclohexane,
Aliphatic, alicyclic and aromatic diamines such as bis (p-aminocyclohexylmethane), m- or p-xylylenediamine, and adibic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid Polyamide resins produced from dicarboxylic acids such as acids, such as aliphatic, alicyclic and aromatic, and produced from aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid. Polyamide resins produced from lactams such as ε-caprolactam and ω-dodecalactam, copolymerized polyamide resins comprising these components, mixtures of these polyamide resins, and the like. Not something. Specifically, polycapramid (nylon 6), polydodecanoamide (nylon 12), polyhexamethylene adipamide (nylon 6.6), polyhexamethylene azelamide (nylon 6.9), polyhexamethylene sebaca Amide (nylon 6,10), polyhexamethylene dodecanoamide (nylon 6,12), polyxylylene adipamide, polyhexamethylene terephthalamide, polyphenylene phthalamide, nylon 6,6,6, poly ( Xylylene adipamide / hexamethylene adipamide) and the like. The polyamide resin preferably has a melting point of 200 ° C. or higher. The molecular weight is not particularly limited, and usually has a relative viscosity of 1. (measured in 98% sulfuric acid according to JIS K 6810-1970).
Eight or more polyamide resins are used, but those having 2.2 or more are particularly preferable from the viewpoint of physical properties. A polyamide resin copolymerized with a branching agent within a range that does not impair moldability can be used depending on the molded article. A particularly preferred polyamide is 96
The relative viscosity is 2.2 to 3.5 as measured with a 1% solution in% sulfuric acid.

In the present invention, as the polypropylene resin used for adjusting the components (b) and (c), any of isotactic and atactic can be used, but isotactic is preferred. In particular, the component (b) is preferably a crystalline polypropylene resin having an intrinsic viscosity (tetralin at 135 ° C.) of 1.2 to 3.0, and the component (c) having an intrinsic viscosity of 2.0 to 3.0. In addition to the homopolymer, a random or block copolymer with another olefin containing 80 mol% or more of a propylene component can also be used. Polypropylene resin is ASTM D-1238-62T (230 ℃
The melt flow rate obtained under a load of 2160 g) is 0.2 to 25 g / 10 min for the component (b), and 0.2 to 3.0 g / 1 for adjusting the component (c).
0 minutes is preferred.

(C) The modifying agent to be modified (grafted copolymerized) with the polypropylene resin to obtain the modified polypropylene resin as the component is selected from unsaturated carboxylic acids and derivatives thereof,
As unsaturated carboxylic acids, acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endo-bicyclo (2,2,1)
Hept-5-ene-2,3-dicarboxylic acid (nadic acid), methyl-endocis-bicyclo (2,2,1) hept-5-ene-2,3-dicarboxylic acid (methylnadic acid)
Etc. can be exemplified. As derivatives of unsaturated carboxylic acids,
Reactive derivatives such as acid halides, amides, imides, acid anhydrides and esters of the above-mentioned acids are exemplified. Specifically, maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate,
Glycidyl maleate can be exemplified. Among these,
Unsaturated dicarboxylic acids or unsaturated dicarboxylic anhydrides are preferably used. Particularly, maleic acid, nadic acid, or acid anhydrides thereof are preferred.

These modifiers are used in a range of 0.05 to 2.0 parts by weight based on 100 parts by weight of the polypropylene resin.

The method of reacting (grafting and copolymerizing) the modifying agent with the polypropylene resin is not particularly limited, but it is preferable that the resulting modified polypropylene resin does not contain undesired components such as glue. Further, when the fluidity is reduced, the processability is deteriorated, which is not desirable. Specifically, for example, a graft reaction is caused by blending the above-mentioned polypropylene resin, a modifying agent, and a radical generator and melt-kneading, whereby a modified polypropylene resin is obtained. As the radical generator, known organic peroxides or diazo compounds can be used. Specific examples include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, cumene hydroperoxide, azobisisobutyronitrile, and the like. The amount of the radical generator used is 0.02% by weight or more, preferably 0.02 to 0.5% by weight, based on the polypropylene resin.

The composition of the present invention may further contain other reinforcing agents, additives and the like. As a reinforcing agent, an inorganic reinforcing agent or a fibrous reinforcing agent is used, and the main ones are glass fiber, glass beads, carbon fiber, aramid fiber, talc, wollastonite, mica, silica, clay, calcium carbonate, etc. And used alone or in combination. Such a reinforcing agent may be used in an amount of 0 to 120 parts by weight based on 100 parts by weight of the total of the components (a), (b) and (c).

Additives include impact modifiers, thermal aging inhibitors, UV absorbers, and various other auxiliaries.

Usually, (a) a polyamide resin, (b) a polypropylene resin, and (c) a modified polypropylene resin are mixed under heating, and the reinforcing agent and the additive aid are mixed at an initial stage, an intermediate stage, or a final stage of the mixing. Is added, especially for the reinforcing agent, the amount of addition is Δ (a) + (b) +
(C) If｝ = 100 parts by weight, and if it exceeds 10 parts by weight, it is desirable to add each of the polymers (a), (b) and (c) after melting and blending.

For the mixing, a conventionally known device can be used. For example, a kneading apparatus such as a reactor equipped with a stirring blade, a single-screw or twin-screw extruder, a Banbury mixer, and a kneader mixing roll can be used alone or in combination. The temperature of the heating and mixing is preferably equal to or higher than the melting points of the polyamide resin (a), the polypropylene resin (b), and the modified polypropylene resin (c).

The mixing ratio of the above components (a), (b) and (c) is as follows: (a) / [(b) + (c)] = 80/20 to 70 to 30 (weight ratio) (b) / (C) = 90 / 10-0 / 100, and the melt flow rate of the blend of the component (b) and the component (c) at 2160 g at 230 ° C. is 2 to 35 g / 10 min, preferably 2 -20 g / 10 min, more preferably 2-15 g / 10 min.

(Examples) Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

In this embodiment, the relative viscosity of the polyamide resin is 2.53.
Nylon 6 (1 g / mol in 98% sulfuric acid, 25 ° C.) and nylon 66 with a relative viscosity of 2.73 were used. As a polypropylene resin, (Sumitomo Chemical, Sumitomo Noblen Y101) MFR = 12 (g / 10
Min) and (Sumitomo Noblen D501) MFR = 0.4 (g / 10 min). The test pieces in the examples were evaluated by the following test methods.

(1) Flexural strength ASTM D-790 (2) Flexural modulus ASTM D-790 (3) Izot impact value ASTM D-256 (with notch, 1/2 inch) (4) Deflection temperature under load ASTM D-648 (5 ) Dupont surface impact Dupont method (upward convex 3mmφ, pilot hole 6mmφ) (A) Preparation of modified polypropylene resin (c) Maleic anhydride and dicumyl peroxide in the amounts shown in Table 1 were added to 100% by weight of the polypropylene resin, mixed uniformly, and then supplied to a 30 mmφ twin screw extruder manufactured by Ikegai. Then, a maleic anhydride modification reaction was performed at a cylinder temperature of 150 ° C to 220 ° C to obtain a modified polypropylene resin.

(B) Preparation and evaluation of the resin composition of the present invention Table 2 shows the above (a) polyamide resin, (b) polypropylene resin, (c) modified polypropylene resin and reinforcing agent.
The pellets were blended at a ratio shown in Table 3 using a 30 mmφ twin screw extruder to produce pellets. The cylinder temperature at that time is 265 ° C. when nylon 6 is used, and 290 ° C. when nylon 66 is used. The resulting pellets were vacuum dried at 70 ° C. for 16 hours. This pellet was heated at a cylinder temperature of 265 ° C (6N
Y), a test piece was molded by an injection molding machine adjusted to 290 ° C (66NY) and a mold temperature of 80 ° C. The physical properties of the obtained molded article were evaluated, and the results are shown in Tables 3 and 4.

Claims (1)

(57) [Claims] An unsaturated carboxylic acid or a derivative thereof is graft-copolymerized with 100 parts by weight of (a) a polyamide resin, (b) a crystalline polypropylene resin and (c) 100 parts by weight of a crystalline polypropylene resin. A composition comprising a modified polypropylene resin, wherein (a) / [(b)
+ (C)] = 80/20 to 70/30 (weight ratio), (b) / (c)
= 90/10 to 0/100 and a melt flow rate at 230 ° C and 2160 g of a blend of the component (b) and the component (c) is 2 to 35 g / 10 minutes. Composition.