JPH083441A - Method for producing polyamide molded body - Google Patents

Abstract

PURPOSE:To increase the mol. wt. of a polyamide resin compsn. comprising nylon 46 resin, nylon 6 and/or nylon 66 resin, and an inorg. filler by melt mixing, kneading, and reacting it with a compd. represented by a specific formula. CONSTITUTION:A polyamide resin mixture is formed which comprises 60-90wt.% nylon 46 resin and 40-10wt.% nylon 6 and/or nylon 66 resin and satisfies the relation: [NH2]-[COOH]>20 {wherein [NH2] and [COOH] are the amts. of terminal amino groups and terminal carboxyl groups, respectively, in g- equivalent/100<6>g}. A polyamide molding is obtd. by melt mixing and kneading 100 pts.wt. the resin mixture, 3-40 pts.wt. inorg. filler, and 0.3 pt.wt. or higher, pref. 0.75-2.00 pts.wt., compd. represented by the formula [wherein X is an optionally substd. ethylene or trimethylene group; the ring structure is 5- or 6-membered; D is 1-10C alkylene, 6-15C arylene, etc.; and n is 0 or 1] [e.g. 2,2'-m- phenylenebis(2-oxazoline)] and molding the resulting compsn. while subjecting it to reaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyamide molded article, and more particularly to a method for producing a nylon 46 molded article having a high molecular weight during melt molding.

[0002]

Nylon 46 made from tetramethylenediamine or its functional derivative and adipic acid or its functional derivative is excellent in mechanical strength such as tensile strength, bending strength and impact strength, and also has heat resistance and sliding characteristics. Because it is also excellent, it has great utility value as a useful engineering plastic.

Conventionally, this resin is mainly produced by injection molding,
General-purpose polyamide centered on nylon 66 has heat resistance,
It has been applied to applications where sliding properties and chemical resistance are insufficient.
However, recently, product development by blow molding has been actively carried out centering on the air intake around the engine and intake manifold, and general-purpose polyamide lacks heat resistance, so development of nylon 46 with excellent blow moldability Has come to be required. Further, in order to develop new applications, the development of nylon 46 suitable for extrusion molding mainly on pipes is also required.

In order to be compatible with these molding methods, it is desirable that the viscosity is high and the crystallization rate is slow. However, since nylon 46 has a low viscosity when melted and has a high crystallization rate, blow molding or extrusion molding is difficult with ordinary nylon 46. In order to be compatible with these molding methods, it is necessary to increase the viscosity at the time of melting, and there is a strong demand for a method for manufacturing a molded product using high molecular weight nylon 46.

In the meantime, in order to obtain a high-molecular weight molded product, the conventional method is to melt-mold a high-molecular-weight chip in a kneader such as an extruder, but in the case of nylon 46, the resin By nature, it is difficult to increase the molecular weight by an economical method.

That is, since the melting point is as high as 290 ° C. and it is close to the decomposition point of the resin, it is impossible to reach the degree of polymerization which can be used as a molded product by the usual melt polymerization method. The special solid-state polymerization method described in JP-A-56-149431 must be used. Therefore, in order to further improve the degree of polymerization, it is necessary to adopt more severe solid-state polymerization conditions, which is not only low in productivity but also
It is difficult to control the degree of polymerization. On the other hand, as another method for obtaining a polyamide having a high degree of polymerization, British Patent No. 693645 discloses a method in which a bis-N-acyllactam type chain linking agent is added during the polymerization of the polyamide. -17
In 1732, there is proposed a method in which a carbamoyllactam type chain linking agent is added to polyamide and the reaction is carried out in an extruder. However, in the case of nylon 46, the former method by melt polymerization cannot be adopted, and the latter method is not satisfactory because the effect of increasing the degree of polymerization of the polymer obtained is small.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to obtain a high molecular weight nylon 46, regardless of the solid-state polymerization method which has low productivity and is difficult to control the degree of polymerization. It is an object of the present invention to provide a method capable of achieving a high degree of polymerization and in which the decrease in the degree of polymerization is extremely small even when the residence time at a high temperature becomes long due to molding.

The present inventors have already proposed in JP-A-3-62826 a method for obtaining a high molecular weight nylon 46 molded article. In this method, amino terminal groups of 46 molecules of nylon are linked with a biscaprolactam compound to increase the molecular weight. However, after the examination,
Although the molecular weight is remarkably increased by the use of biscaprolactam, nylon 46 has a high molding temperature. Therefore, when the residence time in molding is long, the polymerization degree once increased may decrease and the thickening effect may be impaired. understood. The present invention relates to a method for efficiently obtaining a high-molecular-weight nylon 46 molded article even under such circumstances.

[0009]

The present inventors have arrived at the present invention as a result of extensive studies aimed at achieving the above object.

The present invention relates to (A1) nylon 46 resin 60
To 90% by weight and (A2) 40 to 10% by weight of nylon 6 and / or nylon 66 resin satisfying the following formula: [NH ₂ ]-[COOH]> 20 (where [NH ₂ ] and [COOH] Is gram equivalent /
It represents the amount of terminal amino groups and the amount of terminal carboxyl groups in 10 ⁶ gram units. ) Polyamide resin mixture 10
A polyamide resin composition prepared by blending 5 to 40 parts by weight of (B) an inorganic filler with respect to 0 parts by weight is (C) represented by the following general formula (I).

[0011]

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[Wherein X is a divalent organic group selected from the group consisting of ethylene, substituted ethylene, trimethylene and substituted trimethylene, and the ring structure is a 5-membered ring or a 6-membered ring. The substituent of the substituted ethylene or substituted trimethylene is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, and 8 to 8 carbon atoms.
20 aralkyl groups. D in the formula has 1 to 1 carbon atoms
It is a divalent organic group selected from the group consisting of an alkylene group having 0, an arylene group having 6 to 15 carbon atoms, a cycloalkylene group having 5 to 12 carbon atoms, and an aralkylene group having 8 to 20 carbon atoms. Further, n in the formula is 0 or 1. ] It is a manufacturing method of the polyamide molded object characterized by shape | molding in a desired shape, making it react in a melt-kneading machine with at least 0.3 weight part of the compound shown by these.

The present invention will be described in detail below.

The component (A1) nylon 46 resin used in the present invention is a polyamide obtained by a condensation reaction using adipic acid or its functional derivative as the acid component and tetramethylenediamine or its functional derivative as the amine component. However, a part of the adipic acid component or the tetramethylenediamine component may be replaced with another copolymerization component. Preferred embodiments of nylon 46 resin are described in JP-A-56-149430 and JP-A-56-149431.

The nylon 6 resin as the component (A2) used in the present invention is a linear polymer obtained by polymerizing ε-caprolactam. Monomers other than ε-caprolactam may be copolymerized or blended within a range that does not impair the basic properties of nylon 6. Here, in order to prepare Nylon 6 having more amino terminal groups than carboxyl terminal groups, it is necessary to add a small amount of an amine component to ε-caprolactam for polymerization. In this case, the amine component may be a monoamine, but it is more advantageous to use a diamine from the viewpoint of polymerization rate. As the diamine, hexamethylenediamine, aliphatic amine such as m-xylylenediamine, p-phenylenediamine, m-
Examples of aromatic amines such as phenylenediamine,
Any material having heat stability may be used.

The component (A2) nylon 66 resin used in the present invention is a polyamide containing polyhexamethylene adipamide and hexamethylene adipamide units as main constituents. It can be obtained by a method in which a substantially equimolar salt of methylenediamine and adipic acid is charged into a polymerization tank together with water and polymerization is carried out at a temperature of about 250 to 300 ° C. under normal pressure, increased pressure or reduced pressure. At this time, as in the case of Nylon 6, by adding a small amount of amine component and polymerizing, Nylon 6 having more amino terminal groups than carboxyl terminal groups is polymerized.
6 resins can be obtained.

Here, the essential requirement for the component (A2) is the amount of its terminal group, and [NH ₂ ]-[COOH]> 20 (where [NH ₂ ] and [COOH] are each gram equivalent / gram equivalent /
It is necessary to satisfy the condition (representing the amount of terminal amino groups and the amount of terminal carboxyl groups in 10 ⁶ gram units). If this condition is not satisfied, in addition to the high degree of polymerization not being finally obtained, there is a large decrease in melt viscosity when the residence time in molding is long, and therefore a high viscosity during molding can be obtained. Absent. A particularly preferred range is [NH ₂ ]-[COO
H]> 40.

The proportion of the components (A1) and (A2) in the present invention is 60 to 90:40 to 10 by weight.
The component (A2) is an essential component for obtaining a high viscosity at the time of molding and an appropriate decrease in the crystallization rate, and the ratio thereof is 10
If it is less than wt%, this improvement effect is small, while 4
When it exceeds 0% by weight, the heat resistance represented by HDT (load deflection temperature) and the like is lowered, and the characteristics of nylon 46 are impaired, which is not preferable.

The inorganic filler as the component (B) used in the present invention includes fibrous and powdery fillers. Examples of the fibrous filler include glass fiber, aramid fiber, carbon fiber, potassium titanate whiskers, boron whiskers and the like. Examples of the powdery filler include kaolin, wollastonite, talc, mica, calcium carbonate, glass flakes and the like, and two or more kinds of them may be used in combination. These fillers have the effects of increasing the heat resistance expressed on a scale such as HDT and increasing the viscosity during molding. The addition amount is (A
It is 3 to 40 parts by weight with respect to 100 parts by weight of the polyamide resin mixture consisting of 1) and (A2). When it is less than 3 parts by weight, the heat resistance represented by HDT is low, while when it exceeds 40 parts by weight, the extensibility during blow molding is impaired, which is not preferable. A particularly suitable addition range is 10 to 30 parts by weight.

Of these inorganic fillers, glass fiber is particularly preferable, and the glass fiber is not particularly limited as long as it is generally used for reinforcing resin. These may be coated with a sizing agent (for example, a polyurethane-based or polyvinyl acetate-based sizing agent), a coupling agent (for example, a silane compound or a borane compound), or another surface treatment agent.

The compound (C) used in the present invention is represented by the following general formula (I).

[0022]

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In the formula, X is a divalent organic group, and the ring structure is a 5-membered ring or a 6-membered ring. Examples of such X include ethylene, substituted ethylene, trimethylene, and substituted trimethylene. The substituted ethylene or substituted trimethylene has a substituent having 1 to 10 carbon atoms and 6 to 1 carbon atoms.
5 aryl groups, C5-12 cycloalkyl groups,
Examples thereof include an aralkyl group having 8 to 20 carbon atoms. More specifically, examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethylhexyl, nonyl, decyl and the like, and examples of the aryl group include phenyl, naphthyl, diphenyl and the following general formula ( II) represented by an aryl group,

[0024]

[Chemical 4]

(Here, R'is --O--, --CO--, --S--, --SO
₂-,-CH₂-,-CH₂CH₂― 、 ― C (CH ₃)₂-Etc. )
And the like, and cycloalkyl is cyclohexyl.
Sill can be illustrated. Of these, X is ethylene,
Trimethylene is particularly preferred. In the formula, D is a divalent organic group
Is, for example, an alkylene group having 1 to 10 carbon atoms, a carbon number
6 to 15 arylene group, 5 to 12 carbon cycloalkyl
Len group, aralkylene group having 8 to 20 carbon atoms, and the like.
It More specifically, the alkylene group is methylene,
Ethylene, propylene, butylene, pentamethylene,
Xamethylene, heptamethylene, octamethylene, nona
Examples are methylene, decamethylene, dimethylmethylene, etc.
Phenylene and naphthylene as the arylene group.
And diphenylene, and an aromatic group represented by the following general formula (III):
Rylene group,

[0026]

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(Here, R'is --O--, --CO--, --S--, --SO
₂-,-CH₂-,-CH₂CH₂― 、 ― C (CH ₃)₂-Etc. )
And the like, and examples of cycloalkylene include cyclohexyl.
Xylene can be illustrated.

Further, n in the formula is 0 or 1.

The compound represented by the general formula (I) has a 5-membered ring as a compound called bisoxazoline and a 6-membered ring as a compound called bisoxazine. Specifically, the following compounds can be exemplified.

2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4,4-dimethyl-2-oxazoline), 2 2,2'-bis (4-ethyl-2-oxazoline) 2,2'-bis (4,4-diethyl-2-oxazoline), 2,2'-bis (4-propyl-2-oxazoline), 2, 2 '
-Bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2-oxazoline), 2,2'-bis (4-phenyl-2-
Oxazoline), 2,2'-bis (4-cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,
2'-m-phenylene bis (2-oxazoline) 2,2'-o-phenylene bis (2-oxazoline), 2,2'-p-phenylene bis (4-methyl-2-oxazoline), 2,2 ' -p-phenylene bis (4,4-dimethyl-2-oxazoline), 22'-m-phenylene bis (4-methyl-2-oxazoline), 2,2'-m-phenylene bis (4,4-dimethyl) -2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexamethylenebis (2
-Oxazoline), 2,2'-octamethylenebis (2-oxazoline), 2,2'-decamethylenebis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2-oxazoline), 2 Bisoxazolines such as 2,2'-tetramethylenebis (4,4-dimethyl-2-oxazoline), 2,2'-cyclohexylenebis (2-oxazoline), and 2,2'-diphenylenebis (2-oxazoline) Compound; 2,2'-bis (5,6-dihydro-
4H-1,3-oxazine), 2,2'-methylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-ethylenebis (5,6-dihydro-4H-1,3 -Oxazine), 2,2'-propylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-butylenebis (5,6-dihydro-4H-1,3-oxazine), 2 , 2'-hexamethylenebis (5,6-dihydro-4H-1,3-oxazine),
2,2'-p-phenylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylene bis (5,6-dihydro-4H-1,3
-Oxazine), 2,2'-naphthylenebis (5,6-dihydro-4)
H-1,3-oxazine), 2,2'-p, p'-diphenylene bis (5,
6-dihydro-4H-1,3-oxazine) and other bisoxazine compounds.

Of these compounds, 2,2'-bis (2
-Oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline),
2,2'-bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-
p-Phenylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylenebis (5,6-dihydro-4H-1,3-
Oxazine is preferred.

These compounds (C) can be easily prepared by a method in which a corresponding bisamide alcohol is treated with a dehydrating agent such as concentrated sulfuric acid or thionyl chloride to close the ring, or a method in which the corresponding bisamide halide is treated with an alkali to close the ring. Although it can be synthesized, it is not limited to these methods, and other methods can be appropriately used.

In the present invention, a polyamide resin composition prepared by mixing (B) with a polyamide resin mixture comprising (A1) and (A2) is reacted with the compound (C) represented by the general formula (I). A general method is to dry-blend the composition in advance and melt-knead the composition.

Compound (C) for nylon 46
Is 0.3 part or more based on 100 parts by weight of the polyamide resin mixture. If the addition amount is too small, the thickening effect is insufficient, and the particularly preferable addition amount is 0.75 to 2.00.
%. Even if a certain amount or more is added, the thickening effect is saturated and it becomes economically negative.

The melting temperature at this time is 5 to 30 ° C., preferably 5 to 15 ° C. higher than the melting point of nylon 46, and the kneading time is 1 to 15 minutes, preferably 2 to 6 minutes.

According to the present invention, it is possible to increase the degree of polymerization of nylon 46, which results in an increase in viscosity during melting and a decrease in crystallization temperature. As a result, it becomes possible to manufacture a molded body by blow molding or extrusion molding, which has been difficult in the past, and it becomes possible to use nylon 46 resin beyond the frame of injection molding.

[0037]

EXAMPLES Examples will be described below. In addition, the measurement of various characteristics in Examples and Comparative Examples was performed by the following methods. (1) Terminal group amount The amino terminal group amount [NH ₂ ] was determined by dissolving the polymer in m-cresol and titrating with 0.01 N p-toluenesulfonic acid. Amount of terminal carboxyl group [COOH was obtained by dissolving the polymer in benzyl alcohol and dropping with 0.1N sodium hydroxide. (2) Deflection Temperature Under Load (HDT) According to ASTM D648, the load was measured at 264 Psi and the thickness of the test piece was 1/4 inch. (3) Crystallization temperature Differential Scanning Calor made by Du Pont Instruments
Temperature rise / fall rate 20 ℃ / min, 330 ℃
Was measured for a holding time of 3 minutes. (4) Melt viscosity It was measured using RHEOGRAPH2002 manufactured by GOTTFERT at a measurement temperature of 300 ° C. and a holding time of 4 to 15 minutes. It was measured with a shear rate 1000 (1 / sec).

The following materials were used in Examples and Comparative Examples.

As the constituent component (A1) nylon 46, STANYLKS400 manufactured by DSM Co. of the Netherlands was used.

Component (A2) The following (a) to (e) were used as nylon 6 and nylon 66.

(A) 0.26 mol% of diethylenetriamine was added to ε-caprolactam to carry out melt polymerization, washing with hot water, and drying to obtain [η] = 1.08, [NH ₂ ]
= 97, [COOH] = 28, water content = 0.05%, and monomer content = 0.2%.

(B) By adding 0.25 mol% of m-xylylenediamine to ε-caprolactam, melt-polymerizing, washing with hot water and drying [η] = 1.41, [NH ₂ ]
= 66, [COOH] = 18, moisture content = 0.05%, and monomer content = 0.2% were obtained.

(C) Melt polymerization of ε-caprolactam,
By washing with hot water and drying [η = 1.34, [NH
₂ ] = 45, [COOH] = 46, moisture content = 0.05%
Chips having a monomer content of 0.2% were obtained.

(D) 0.39 mol% of terephthalic acid was added to ε-caprolactam, melt polymerization was carried out, hot water washing and drying were carried out to obtain [η] = 1.21, [NH ₂ ] = 5.
A chip having [COOH] = 86, water content = 0.05%, and monomer content = 0.2% was obtained.

(E) Hexamethylenediamine is added to AH salt in an amount of 0.25 mol%, and melt polymerization is performed [η] = 1.37.
Chips with [NH ₂ ] = 68 and [COOH] = 20 were obtained.

As component (B) inorganic filler, length 3 m
m chopped strand cut glass fiber (manufactured by Nippon Electric Glass Co., Ltd.) was used.

The polyamide resin mixtures of Examples and Comparative Examples were extruded by a twin-screw extruder (TEX44, manufactured by Nippon Steel Co., Ltd.) at a cylinder temperature of 270 to 330 ° C. and pelletized. A predetermined amount of bisoxazoline powder was dry-blended with the obtained pellet and used for the test.

Compositions and test evaluation results are shown in Tables 1 and 2 as Examples and Comparative Examples.

The blow moldability in the table was judged by the following method. Direct blow molding machine (SE5I / BA
2, manufactured by Sumitomo Heavy Industries), cylinder temperature 270-29
A rectangular shaped body was blow-molded at 0 ° C. and a die head temperature of 270 to 280 ° C., and it was judged from the drawdown property during molding, the wall thickness, the presence or absence of rupture during blowing, the surface property and the like.

[Examples 1 to 10 and Comparative Examples 1 to 7] In Examples 1 to 3, the melt viscosity was increased and good blow moldability was obtained. On the other hand, in Comparative Example 1, since nylon 6 is not used, the crystallization temperature is high and it solidifies quickly, so that sufficient blow moldability cannot be obtained. On the other hand, in Comparative Example 2, since the amount of nylon 6 is too large, the HDT becomes low and the characteristics of nylon 46 are lost.

Examples 4 and 5 are examples in which the type of component (A2) is changed, and similar effects can be obtained.

In Comparative Examples 3 and 4, as the component (A2), [NH
₂ ]-[COOH]> 20 is an example using Nylon 6 which does not satisfy the condition, and not only the melt viscosity is low, but also the viscosity decrease is large when the melt residence time becomes long. In contrast, in Example 3, the decrease in melt viscosity is small.

Examples 6 and 7 are examples in which the amount of bisoxazoline was changed. In the system containing no bisoxazoline (Comparative Example 7), the viscosity was low and the blow moldability was poor.

Comparative Example 5 is an example in which the component (B) is not contained, the viscosity increase is insufficient, and the HDT becomes too low, which is not preferable. On the contrary, too much glass fiber (Comparative Example 6)
If so, the elongation fluidity is impaired and the blow moldability becomes poor.

In Example 9, the kind of bisoxazoline was changed, and the same effect was obtained.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

According to the present invention, (A1) nylon 46,
(A2) It was possible to increase the molecular weight by reacting a polyamide resin composition composed of nylon 6 and / or nylon 66 satisfying specific conditions and (B) an inorganic filler with a bifunctional oxazoline or oxazine as a chain linking agent. . In addition, it is possible to manufacture a nylon 46 resin molded body that is compatible with blow molding or extrusion molding, in which the decrease in molecular weight when kept at high temperature is small, and the heat resistance of nylon 46 is maintained, and the like. Is played.

Claims (2)

[Claims] 1. (A1) 60 to 90% by weight of nylon 46 resin and (A2) 40 to 10% by weight of nylon 6 and / or nylon 66 resin satisfying the following formula: [NH ₂ ]-[COOH]> 20 (Here, [NH ₂ ] and [COOH] are each gram equivalent /
It represents the amount of terminal amino groups and the amount of terminal carboxyl groups in 10 ⁶ gram units. ) Polyamide resin mixture 10
A polyamide resin composition prepared by blending 3 to 40 parts by weight of (B) an inorganic filler with respect to 0 parts by weight of (C) is represented by the following general formula (I): [In the formula, X is a divalent organic group selected from the group consisting of ethylene, substituted ethylene, trimethylene, and substituted trimethylene, and the ring structure is a 5-membered ring or a 6-membered ring. The substituent of the substituted ethylene or substituted trimethylene has 1 to 1 carbon atoms.
An alkyl group of 0, an aryl group of 6 to 15 carbon atoms, a cycloalkyl group of 5 to 12 carbon atoms, and an aralkyl group of 8 to 20 carbon atoms. In the formula, D is an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 15 carbon atoms, and 5 to 12 carbon atoms.
And a divalent organic group selected from the group consisting of C8 to C20 aralkylene groups. Further, n in the formula is 0 or 1. ] At least 0.3 part by weight of the compound shown in the above is reacted in a melt-kneader and molded into a predetermined shape, which is a method for producing a polyamide molded body. 2. The compound represented by the general formula (I) is 2,
2'-m-phenylene bis (2-oxazoline) or 2,2'-p-phenylene bis (2-oxazoline)
The method for producing a polyamide molded body according to claim 1, wherein