JPH02151654A - Thermoplastic polyamide resin composition - Google Patents

Abstract

PURPOSE:To effectively prepare a thermoplastic polyamide resin compsn. with excellent molding properties by compounding a polyamide resin with a specific org. monooxazoline compd. CONSTITUTION:100 pts.wt. polyamide resin having a relative viscosity (in 1% sulfuric acid soln. at 25 deg.C) of pref. 1.5-5.0 (e.g. nylon-6) is mixed with 0.01-15 pts.wt., pref. 0.1-12 pts.wt., org. monooxazoline compd. of the formula (R is a 4-20C hydrocarbon group) (e.g. palmityloxazoline) at 200-350 deg.C.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a thermoplastic polyamide resin composition containing a specific organic monooxazoline compound and having excellent molding properties such as fluidity and high cycleability, and water resistance. It is something.

<Conventional technology> Polyamide resins generally have excellent mechanical properties such as heat resistance, strength, rigidity, and impact resistance, as well as chemical resistance, and have good moldability, so they are used for automobile parts, electrical/electronic parts, a It is used in a wide range of applications, including mechanical parts, filaments, and films.

In recent years, the miniaturization and precision of automobile, electric, electronic, and mechanical parts have progressed significantly, and with this, more advanced molding properties, such as good flowability and high cycle performance, are required of resin materials. Therefore, it has become necessary to further improve the molding processability of polyamide resins, which originally have good molding processability. In response to these demands, several attempts have been made to solve the problem by appropriately modifying the molecular terminals of polyamide resins, and some success has been observed. For example, as shown in JP-A-61-163935 and JP-A-62-10136, polyamide is polymerized in the presence of an organic monoamine or an organic monocarboxylic acid to form a hydrocarbon group at the end. Method for obtaining polyamide or JP-A-61-207436
Examples include a method of kneading and adding a specific alkyl monoepoxide to polyamide as shown in the above publication.

<Problems to be Solved by the Invention> However, the above prior art has the following problems. That is, JP-A-61-163935 and JP-A-62
- Organic monoamines as shown in Publication No. 10136,
Alternatively, when polyamide is polymerized in the presence of an organic monocarboxylic acid, the polymerization time becomes significantly longer, and to compensate for this, a special pressure reduction step is required in the latter half of the polymerization, which inevitably reduces production efficiency. Also, JP-A-61-20
When using the polyamide shown in Publication No. 7436 and a specific alkyl monoepoxide, there is an advantage that the composition can be obtained by an efficient method of melt-kneading the polyamide and the monoepoxide, but the reactivity of the alkyl monoepoxide is not sufficient. Therefore, during short-time melt-kneading, the reaction between the monoepoxide and the polyamide ends is not completed, and the remaining monoepoxide compound bleeds out during heat treatment of the polyamide molded product. In other words, at present, a method for modifying polyamide terminals that is highly efficient and highly effective in improving molding processability has not yet been obtained.

Therefore, an object of the present invention is to obtain a thermoplastic polyamide resin composition that can efficiently improve molding properties.

Means for Solving the Problems In order to solve the above problems, the present inventors investigated additives for modifying the ends of polyamides, and found that a specific organic monooxazoline compound reacts extremely efficiently with the ends of polyamides. The inventors have discovered that it is possible to provide a terminally modified polyamide with excellent moldability without problems such as bleed-out of residual materials, and have arrived at the present invention. That is, one aspect of the present invention is a thermoplastic polyamide resin composition comprising 100 parts by weight of a polyamide resin and 0.01 to 15 parts by weight of an organic monooxazoline compound represented by the following general formula (I).

\0-CH.

(Here, R represents a hydrocarbon group having 4 to 20 carbon atoms.) The organic monoxazoline compound used in the present invention is a monooxazoline compound having a hydrocarbon group having 4 to 20 carbon atoms, preferably 7 to 20 carbon atoms. and the basic hydrocarbon group can be straight chain, sidearm, or aromatic. Specific examples include n-butyloxazoline, l-butyloxazoline, n-pentyloxazoline, neopentyloxazoline, n-hexyloxazoline, n-
Hebutyloxazoline, n-octyloxazoline, 2
-ethylhexyloxazoline, n-decyloxazoline, l-decyloxazoline, lauryloxazoline,
Examples include mystyloxazoline, cetyloxazoline, stearyloxazoline, oleyloxazoline, behenyloxazoline, hexyldecyloxazoline, phenyloxazoline, p-methylphenyloxazoline, p-ethylphenyloxazoline, and p-t-butylphenyloxazoline.

The amount of the organic monooxazoline compound used in the present invention is 0.01 to 15 parts by weight, preferably 0.1 to 12 parts by weight, per 100 parts by weight of the polyamide resin. If the amount added is less than 0.01 part by weight, the effect of improving moldability such as fluidity and key shape is not sufficient, so it is not preferable.
If the amount added exceeds 15 parts by weight, problems such as foaming during melt molding or a decrease in heat resistance of the molded product may occur, which is not preferable.

The polyamide resin used in the present invention is a polyamide whose main components are an amino acid, a lactam, or a diamine and a dicarboxylic acid. Specific examples of constituent components include lactams such as ε-caprolactam, enantlactam, and ω-laurolactam, ε-aminocaproic acid, and 11-
Amino acids such as aminoundecanoic acid and 12-aminododecanoic acid, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2.2.4-/2.2.4-trimethylhexamethylenediamine, 5 -Methylnonamethylenediamine, m
--1r silylene diamine, P-xylylene diamine,
Diamines such as 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, bis-p-aminocyclohexylmethane, bis-p-aminocyclohexylpropane, isophoronediamine, adipic acid, speric acid, azelaic acid, Sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, 1゜3-
There are dicarboxylic acids such as cyclohexane dicarboxylic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and dimer acid.

These components are subjected to polymerization either alone or in the form of a mixture of two or more, and both the polyamide homopolymer and copolymer thus obtained can be used in the present invention.

Polyamides particularly useful in the present invention include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polyhexamethylene adipamide (nylon 610), and polyundecane amide (nylon 11).
), polydodecanamide (nylon 12), and copolymers and mixtures of these polyamides.

There is no particular restriction on the degree of polymerization of the polyamide used here, and any polyamide having a relative viscosity of 1% sulfuric acid solution at 25° C. within the range of 1.5 to 5.0 can be used.

The method for producing the thermoplastic polyamide resin composition of the present invention is not particularly limited, but a mixture obtained by tri-blending the polyamide resin and additives using a Henschel mixer, ribbon blender, etc., is prepared using a single- or twin-screw extruder, a Banbury mixer, etc.
A method of kneading at 200 to 350° C. using a commonly known melt mixer such as a kneader or a mixing roll, or a method of melt molding by putting the mixer as it is into a molding machine hopper is suitable for the fil.

The thermoplastic polyamide resin composition of the present invention may contain other additives during kneading and molding, such as pigments, dyes, reinforcing agents, fillers, heat resistant agents, oxidative deterioration inhibitors, weathering agents, and lubricants, as long as they do not impair its properties. , a mold release agent, a crystal nucleating agent, a plasticizer, a flame retardant, an antistatic agent, etc. can be added and introduced.

The thermoplastic polyamide resin composition of the present invention has excellent fluidity and mold releasability, and is mainly manufactured by injection molding. Suitable for use in automobile parts, electrical/electronic parts, mechanical parts, etc.

<Example> The present invention will be explained in more detail by showing examples below. In addition, various properties in Examples and Comparative Examples were measured by the following methods.

(1) Relative viscosity of polyamide: JIS K-68 (2
) Terminal modification rate: The amount of carboxyl terminal groups of polyamide before and after introduction of additives was adjusted to 115ON in benzyl alcohol solvent.
The modification rate was calculated by titration with NaOH.

(3) Fluidity temperature - melting point of polyamide + 3
Using an injection molding machine set at 0°C, injection molding was performed at an injection pressure of 500 kg/cd into a 1 mm thick spiral mold set at 80°C, and the flow length was measured, which was used as a measure of fluidity.

(4) Mold release property 2 Length 70mm, Width 60mm, Height 40mm
A box-shaped molded product is continuously molded under the conditions of a cylinder temperature of polyamide melting point + 30°C, injection/cooling time = 10/10 seconds, and molding continues until key shape defects such as deformation due to ejector pins occur. The number of shots was recorded and used as a measure of mold releasability.

Example 1 100 parts by weight of nylon 6 pellets with a relative viscosity of 2.70 and 2.0 parts by weight of valmityl oxazoline were mixed in a Henschel mixer, the resulting mixture was supplied to the hopper of a 30 mmφ single screw extruder, and the mixture was heated at 250°C. The mixture was kneaded at a kneading temperature to form pellets. The nylon 6 composition obtained here was heated at 80°C.
/ After vacuum drying for 16 hours, the terminal modification rate was measured and the cylinder temperature was 250°C and the mold temperature was 8°C using an injection molding machine.
When the fluidity and mold releasability were evaluated at 0°C, the results shown in Table 1 were obtained, and the polyamide assembly obtained here had the terminals effectively blocked and had excellent fluidity and mold releasability. It turned out to be of extremely high practical value.

Comparative Example 1 Kneading and injection molding were carried out in exactly the same manner as in Example 1 except that dodecene-1-oxide was used instead of palmityloxazoline. The results are shown in Table 1. The composition had a low terminal modification rate and had poor properties such as unreacted dodecene-1-oxide contaminating the mold surface.

Examples 2 to 5 Polyamide compositions were obtained in the same manner as in Example 1 by changing the type of polyamide, the type and amount of additives, and their properties were measured, and the results are summarized in Table 1. .

It has been found that all of the compositions obtained here have been efficiently terminal-modified and have excellent moldability with good flowability and mold releasability.

<Effects of the Invention> The purpose of the present invention is to obtain with high efficiency a modified polyamide composition having excellent molding processability such as fluidity and mold releasability.
By adding a specific organic monooxazoline to a polyamide resin as in the present invention, it becomes possible to obtain a polyamide composition that is extremely efficiently terminal-modified and has excellent molding properties.

Claims (1)

[Claims] 100 parts by weight of polyamide resin and the following general formula (I)
Organic monooxazoline compound represented by 0.01 to 15
A thermoplastic polyamide resin composition consisting of parts by weight. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (Here, R represents a hydrocarbon group having 4 to 20 carbon atoms.)