JPH07116357B2 - Polyamide resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyamide resin composition in which the impact resistance of polyamide is improved without impairing the excellent characteristics inherent to polyamide.

Polyamide is excellent in mechanical strength, rigidity, heat resistance, wear resistance and the like as compared with thermoplastic resins such as polyolefin, and is therefore widely used as an engineering plastic in various fields of molding applications.

For example, electrical parts, mechanical parts, automobile parts, general sundries,
It is used in large quantities in the fields of fibers, films, sheets, tubes, etc.
For automobile parts, home electric appliance parts, general equipment parts, etc., those having a high degree of impact resistance are required to withstand a large impact load from the outside. Especially for automobile parts, bumper beams, transmission supports, radiator servos, wheel caps, etc. are applicable.

<Prior Art> Conventionally, various methods have been proposed as a method for improving the impact resistance of polyamide, but a typical method is to add a polymer containing an active group capable of reacting with polyamide and having rubber elasticity. There is a way to do it. For example, it is known to use an elastomer of an unsaturated carboxylic acid-containing olefin as an impact modifier. However, in these methods, although the impact resistance is improved, the rigidity is lowered and the tensile strength, the surface hardness and the like are lowered. That is, although the impact strength is improved, it becomes a soft resin and impairs the excellent properties of polyamide. Therefore, its application destination is limited.

<Problems to be Solved by the Invention> The present inventors have made various studies in order to improve such drawbacks.

<Means for Solving Problems> As a result, polyamide has unit formula It was found that a polyamide resin composition having further improved rigidity, which is an excellent characteristic of polyamide, and a significantly improved impact resistance can be obtained by blending a polymer composed of and based on such findings. The present invention has been achieved.

That is, the present invention provides (A) component: 100 parts by weight of polyamide (B) component: general formula The structural unit (a) represented by A polymer basically composed of a structural unit (b) represented by the formula (1), wherein the structural unit (a) in the polymer is 1
1 to 200 parts by weight of a polymer having 100 to 100 mol% and a structural unit (b) of 99 to 0 mol% [in the formula, R ¹ and R ² are hydrogen atoms, alkyl groups having 1 to 20 carbon atoms or 6 carbon atoms] ~ 8 phenyl group, R ³ represents an alkyl group having 1 to 20 carbon atoms. The present invention provides a polyamide resin composition characterized in that the component (A) and the component (B) are blended in the above proportions.

In the present invention, the component (A) is polycapramide (nylon-6), polyhexamethyleneadipamide (nylon-).
6,6), polyhexamethylene sebacamide (nylon-6,1
0), polyhexamethylene dodecamide (nylon-6,1
2), polyundecane amide (nylon-11), polydodecane amide (nylon-12), and copolyamides and condensed polyamides containing these as the main components.

The polymer of component (B) has the general formula The structural unit (a) represented by 1 to 100 mol%, preferably 20 to 90 mol%, The polymer is basically composed of 99 to 0 mol%, preferably 80 to 10 mol% of the structural unit (b) represented by

[In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or a phenyl group having 6 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 20 carbon atoms. When the amount of the component (a) is small (less than 1 mol%), the dispersibility with the polyamide is deteriorated and good physical properties cannot be obtained.

On the other hand, when the amount of component (a) increases (at 90 mol% or more),
The heat resistance stability of the component (B) is reduced, so that it is not practical. However, by adding a stabilizer or the like, it is possible to disperse it with the polyamide even at 100 mol%, and the addition of the component (B) is effective.

This polymer is 5-norbornene-obtained by Diels-Alder reaction of cyclopentadiene and acrylic acid ester or α-alkyl-substituted acrylic acid ester.
The 2-carboxylic acid ester is polymerized by a metathesis catalyst to give a compound represented by the general formula A polymer having a molecular weight of 10,000 to 350,000 having a structural unit represented by is produced. Next obtained 5-norbornene-2
Hydrolyze the polymer of carboxylic acid ester with alkali. The hydrolysis method is not particularly limited, and it can be hydrolyzed by dissolving the polymer in an organic solvent such as benzene or toluene, dispersing it in water using an emulsifier, and adding an alkali.

Alternatively, the polymer can be hydrolyzed by dissolving the polymer in a water-soluble organic solvent such as dioxane, tetrahydrofuran, dimethylformamide, dimethylsulfoxide and adding an aqueous alkali solution.

Further, the reaction can be performed more efficiently by using the following two-step hydrolysis method. That is, the polymer is dissolved in a water-soluble organic solvent such as acetone or tetrahydrofuran, and an alkaline aqueous solution is added to the solution to heat it for hydrolysis. As the reaction progresses, the polymer is precipitated and the system becomes heterogeneous.Here, water or a dilute alkaline aqueous solution is added as the second stage hydrolysis treatment to homogenize the reaction system, and then the treatment is continued. Done by.

The hydrolyzed polymer is then added with an acid to convert the carboxylic acid salt in the polymer into a carboxylic acid group, The structural unit (a) represented by A polymer consisting of the structural unit (b) represented by
The constitutional ratio of the constitutional unit (a) and the constitutional unit (b) can be changed by the condition of hydrolysis, that is, the amount of alkali added.

The polymer of the component (B) is mixed in an amount of 1 to 200 parts by weight, preferably 2 to 100 parts by weight, relative to 100 parts by weight of the component (A) polyamide. When the ratio of the component (B) to the component (A) is increased, the impact strength of the mixed polymer composition is increased, but the ratio of the component (B) is 1 part by weight relative to 100 parts by weight of the component (A). If it is less than a part, the effect is small. On the other hand, if the amount of the component (B) exceeds 200 parts by weight, the impact strength decreases and the effect is lost.

Further, the rigidity (elastic modulus) increases as the ratio of the component (B) to the component (A) increases, but the rigidity tends to gradually decrease when the ratio of the component (B) exceeds 100 parts by weight. is there.

<Operation> The dispersed state of the components (A) and (B) is extremely good, and a state close to a compatible system is observed by a microscope or the like. The reason why the compatibility between the component (A) and the component (B) is good and the rigidity is increased by mixing the component (A) and the component (B) is not clear. An interaction is expected between the amide bond of the (B) component and the carboxylic acid group of the (B) component, and at the same time, the skeleton structure of the (B) component is
It is presumed that the structure is such that it is easily dispersed in the components.

In addition to these components (A) and (B), pigments, stabilizers,
You may add various additives, such as an inorganic filler and glass fiber.

The components (A) and (B) are mixed by dry blending,
Alternatively, the components (A) and (B) are dry blended and then melt-kneaded to form pellets. The melt kneading is performed using a Banbury mixer, a roll kneader, an extrusion molding machine, or the like.
These mixed polymers are shaped into a desired shape by extrusion molding, injection molding, compression molding or the like.

<Example> Hereinafter, the present invention will be described in more detail with reference to Examples (and Comparative Examples). The evaluation of the test pieces in Examples and Comparative Examples is the result of measurement according to the following method.

(1) Bending test JIS K 7203-1973 (2) Impact test ISO 6603/2 ・ 2 (Method B) Further, the test pieces used in the examples and comparative examples were formed in absolutely dry condition, and the temperature was 23 It was measured at ° C.

Example 1 Nylon-6 (general injection grade) was used as the polyamide of the (A) component, and as the (B) component. Of m: n = 40: 60 (mol) of (A) component 10
A sample was prepared in which 5 parts by weight of the component (B) was added to 0 parts by weight.

The polymer as the component (B) was synthesized by the following method. 5-norbornene-2 obtained by Diels-Alder reaction of cyclopentadiene and methyl acrylate
-The methyl ester was polymerized using a metathesis catalyst. Next, the obtained polymer was dissolved in tetrahydrofuran, and an aqueous solution of potassium hydroxide was further added for hydrolysis. Since the polymer was precipitated as the hydrolysis proceeded, water was further added to proceed the reaction. Next, acetic acid was used to convert the carboxylic acid salt into a carboxylic acid group, which was washed with water and dried to obtain the desired polymer. In addition, the ratio of the structural unit (a) and the structural unit (b) in the component (B) was confirmed by infrared absorption spectrometry.

5 parts by weight of the component (B) is dry blended with 100 parts by weight of the component (A), and pelletized using an extruder.
A polyamide resin composition in which the component (A) and the component (B) were mixed was obtained.

The obtained polyamide resin composition using an injection molding machine,
A sheet-shaped sample having a thickness of 2 mm was prepared.

By the bending test, a bending elastic modulus of 26,700 kg / cm ² was obtained. In addition, the impact strength of the dart drop was 138 kg · cm. All of them show larger values than the polyamide alone (see Comparative Example 1).

Example 2 Nylon-6 (general injection grade) was used as the polyamide of the component (A) and the polyamide of the component (B) was used. Of m: n = 40: 60 (mol) of (A) component 10
A sample was prepared by adding 10 parts by weight of the component (B) to 0 parts by weight.

The polymer as the component (B) was prepared in the same manner as in Example 1. The same method as in Example 1 was used to prepare the sample, and a sheet-like sample having a thickness of 2 mm was obtained.

The bending elastic modulus of the obtained sample was 28,000 kg / cm ² , and the impact strength due to dart drop was 147 kg · cm. All of them show larger values than the polyamide alone.

Example 3 Nylon-6 (general injection grade) was used as the polyamide of the component (A), and the polyamide of the component (B) was used. Of m: n = 40: 60 (mol) of (A) component 10
A sample was prepared by adding 10 parts by weight of the component (B) to 0 parts by weight.

The polymer as the component (B) was prepared in the same manner as in Example 1. The same method as in Example 1 was used to prepare the sample, and a sheet-like sample having a thickness of 2 mm was obtained.

The bending elastic modulus of the obtained sample was 28,800 kg / cm ² , and the impact strength due to dart drop was 154 kg · cm. All of them show larger values than the polyamide alone.

Comparative Example 1 Nylon-6 as polyamide (general injection grade)
Using an injection molding machine, a sheet-shaped sample having a thickness of 2 mm was prepared.

The bending elastic modulus of this sample was 23,700 kg / cm ² , and the impact strength due to dart drop was 118 kg · cm.

<Effects of the Invention> With the polyamide resin composition of the present invention, it is possible to improve the impact resistance of the polyamide and further improve the rigidity (flexural modulus) which is its original property.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michiharu Kihira No. 1 Toho-cho, Yokkaichi-shi, Mie Inside the Resin Research Laboratory, Mitsubishi Petrochemical Co., Ltd. (56) Reference JP-A-52-13548 (JP, A) JP Sho 63-83165 (JP, A)

Claims (1)

[Claims] 1. Component (A): 100 parts by weight of polyamide (B) component: general formula The structural unit (a) represented by A polymer basically composed of a structural unit (b) represented by the formula (1), wherein the structural unit (a) in the polymer is 1
1 to 200 parts by weight of a polymer having 100 to 100 mol% and a structural unit (b) of 99 to 0 mol% [in the formula, R ¹ and R ² are hydrogen atoms, alkyl groups having 1 to 20 carbon atoms or 6 carbon atoms] ~ 8 phenyl group, R ³ represents an alkyl group having 1 to 20 carbon atoms. ] The above-mentioned (A) component and (B) component are mix | blended by the said ratio, The polyamide resin composition characterized by the above-mentioned.