JPH11335554A - Polyamide resin composition and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide with ease a polyamide resin compsn. which comprises a polyamide resin and a layered silicate and has a low specific gravity and an excellent stiffness. SOLUTION: This compsn. is prepd. by melt-kneading 65-99.8 pts.wt. polyamide resin, 0.1-20 pts.wt. layered silicate, and 0.1-15 pts.wt. org. onium salt, and sum of all the ingredients being 100 pts.wt. The melt-kneading is conducted at a temp. which is not lower than the 10% wt. loss temp. but no higher than the 90 %.wt. loss temp. of the org. onium salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition comprising a polyamide resin and a layered silicate having improved mechanical properties, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in order to improve the mechanical properties of polyamide resins, it has been practiced to incorporate glass fibers and inorganic fillers into the resins. However, simply melting and kneading these inorganic fillers causes problems such as poor dispersion of the inorganic filler in the resin and poor interfacial adhesion, low impact resistance, and poor surface appearance. Therefore, in order to increase the affinity or binding force between the polyamide resin and the inorganic filler,
There is a method of improving the dispersion of the filler in the resin by applying a coupling treatment such as an organic silane to the surface of the inorganic filler, but such a method is sufficient to improve the compatibility between the resin and the inorganic filler, and is sufficiently improved. Has not reached.
Further, in order to obtain sufficient strength, it is necessary to increase the filling amount of a normal filler, and there is a problem that the obtained resin composition has a high specific gravity.

On the other hand, clay minerals, which are a kind of inorganic layered compounds, have been tried for a long time as fillers. However, in ordinary mixing and kneading, secondary agglomeration occurs and uniform mixing in the resin occurs. Dispersion was difficult. Japanese Patent Application Laid-Open No. 8-12881 discloses an attempt to obtain uniform dispersion by using an interlayer compound having a layered silicate as a host and a specific quaternary ammonium ion guest. In order to obtain it, it is necessary to carry out cation exchange between the layered silicate and the quaternary ammonium ion in a solvent such as water, which has a problem that the process is complicated. In particular, when dispersing the layered silicate in water, if the amount of water is small, the dispersion becomes gel-like, so that a large amount of water is required, and an increase in the size of the production equipment is inevitable. Further, it takes time for drying after recovery from water, and it is necessary to pulverize and pulverize again the intercalation compound obtained by drying, and an improvement has been desired.

Japanese Patent Application Laid-Open Nos. 8-151449 and 9-48856 disclose that a clay mineral is swollen with a solvent, then melt-kneaded with a resin, and a vent port provided in an extruder is maintained at a reduced pressure. An attempt to obtain a uniform dispersion by removing the solvent is disclosed, but the dispersibility is insufficient, and there has been a problem that the process is complicated due to the use of the solvent.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to easily obtain a polyamide resin composition having improved dispersibility of layered silicate and excellent mechanical strength.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the polyamide resin, the layered silicate and the organic onium salt are melt-kneaded to disperse the layered silicate. It has been found that a polyamide resin composition having improved properties and excellent mechanical strength can be easily obtained, and the present invention has been accomplished.

That is, in the present invention, when the total of the following (a) to (c) is 100 parts by weight, (a) 65 to 99.8 parts by weight of a polyamide resin (b) 0.1 to 20 parts by weight of a layered silicate Part (c) a polyamide resin composition obtained by melt-kneading 0.1 to 15 parts by weight of an organic onium salt, and (a) 65 to 99.8 parts by weight of a polyamide resin (b) layered silicate 0.1 to 20 parts by weight (C) 0.1 to 15 parts by weight of an organic onium salt is added (provided that the total of (a) to (c) is 100 parts by weight). The present invention relates to a method for producing a polyamide resin composition, which comprises melting and kneading an onium salt in a temperature range of 10% or more by heating and 90% or less by heating.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The (a) polyamide resin used in the present invention is a polyamide containing amino acids, lactams or diamines and dicarboxylic acids as main raw materials. Representative examples of the raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and paraaminomethylbenzoic acid, ε-caprolactam, ω
Lactams such as laurolactam, tetramethylenediamine, hexamerenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5 -Methylnonamethylenediamine, metaxylenediamine, paraxylylenediamine,
1,3-bis (aminomethyl) cyclohexane, 1,4
-Bis (aminomethyl) cyclohexane, 1-amino-
3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane,
2,2-bis (4-aminocyclohexyl) propane,
Aliphatic, alicyclic, and aromatic diamines such as bis (aminopropyl) piperazine and aminoethylpiperazine, and adipic acid, spearic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-
Chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, aliphatic such as hexahydroisophthalic acid, alicyclic and aromatic dicarboxylic acids, In the present invention, polyamide homopolymers or copolymers derived from these raw materials can be used alone or in the form of a mixture.

In the present invention, particularly useful polyamide resins are polyamide resins having a melting point of 200 ° C. or more and excellent in heat resistance and strength. Specific examples thereof include polycaproamide (nylon 6) and polyhexamethylene. Adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyhexamethylene adipamide / polyhexamethylene Terephthalamide copolymer (nylon 6
6 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66
/ 6I), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I),
Examples include polyxylylene adipamide (nylon XD6) and mixtures or copolymers thereof.

Particularly preferred are nylon 6, nylon 66, nylon 610, nylon 6/66.
Examples thereof include copolymers, nylon 6/12 copolymers, and the like.
It is practically suitable to use the mixture as a mixture depending on the required properties such as heat resistance, toughness, and surface properties.

The degree of polymerization of these nylon resins is not particularly limited, and the relative viscosity measured at 25 ° C. in a 1% concentrated sulfuric acid solution is in the range of 1.5 to 5.0, particularly 2.0 to 4.0. Those in the range of 0 are preferred.

The layered silicate (b) in the present invention has a structure in which plate-like materials having a width of 0.05 to 0.5 μm and a thickness of 6 to 15 Å are laminated, and has a cation exchange capacity of 2 μm.
0 to 300 meq / 100 g, preferably having a cation exchange capacity of 80 to 150 meq / 100 g.
belongs to.

Specific examples of layered silicates include smectite clay minerals such as montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, vermiculite, various clay minerals such as halloysite, kanemite, keniyaite, zirconium phosphate, titanium phosphate and the like. Swelling synthetic mica such as Li-type fluorine teniolite, Na-type fluorine teniolite, Na-type tetrasilicon fluoromica, Li-type tetrasilicon fluoromica, and the like, whether natural or synthesized. good. Among these, smectite clay minerals such as montmorillonite and hectorite, and swellable synthetic mica such as Na-type tetrasilicon fluorine mica are preferred.

(C) The organic onium salts are a group of compounds represented by ammonium salts, phosphonium salts and sulfonium salts. Among them, ammonium salts and phosphonium salts are preferable, and ammonium salts are particularly preferably used. As the ammonium salt, primary ammonium, 2
Any of quaternary ammonium, tertiary ammonium, quaternary ammonium chloride, bromide, acetate, sulfate and the like may be used.

The primary ammonium salt includes salts of decyl ammonium, dodecyl ammonium, octadecyl ammonium, oleyl ammonium, benzyl ammonium and the like.

Examples of the secondary ammonium salt include salts such as methyl dodecyl ammonium and methyl octadecyl ammonium.

Examples of the tertiary ammonium salt include salts such as dimethyldodecylammonium and dimethyloctadecylammonium.

The quaternary ammonium salts include salts of benzyltrialkylammoniums such as benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, benzyldimethyldodecylammonium, benzyldimethyloctadecylammonium, trioctylmethylammonium, trimethyloctylammonium, trimethyl Salts of alkyltrimethylammoniums such as dodecylammonium and trimethyloctadecylammonium, and salts of dimethyldialkylammoniums such as dimethyldioctylammonium, dimethyldidodecylammonium and dimethyldioctadecylammonium are exemplified.

In addition, aniline, p-phenylenediamine, α-naphthylamine, p-aminodimethylaniline, benzidine, pyridine, piperidine,
-Aminocaproic acid, 11-aminoundecanoic acid, 12
Ammonium salts derived from -aminododecanoic acid and the like.

Of these, quaternary ammonium chloride is preferred in view of its availability, and specific examples include trioctylmethylammonium chloride, benzyldimethyldodecylammonium chloride, benzyldimethyloctadecylammonium chloride, and trimethyloctadecylammonium chloride.

These organic onium salts can be used alone or in combination of two or more.

In the present invention, the melting point of the polyamide resin (a) is Ta, and the melting point of the organic onium salt (c) is 10% from the viewpoint that the layered silicate is finely dispersed and the resin composition is given excellent mechanical properties. When the heating loss temperature is Tc10 and the 90% heating loss temperature is Tc90, it is preferable that Tc10 <Ta + 20 <Tc90.

The melting point Ta of the polyamide resin is a temperature at which the crystal of the polyamide is melted, and is measured by a finger scanning calorimetry (DS).
It can be measured by a thermoanalytical method such as C). When the polyamide resin used is amorphous and does not show a melting point, the melting point indicates a temperature at which plastic working becomes possible.

The weight loss on heating of the organic onium salt in the present invention can be measured by thermogravimetry (TG). Specifically, the organic onium salt in a dry state is heated in a nitrogen atmosphere at a heating rate of 20 ° C. /
Use the value measured in min. The 10% loss on heating temperature Tc10 of the organic onium salt (c) refers to the temperature at which the weight of the initial sample decreases by 10% when the weight loss on heating is measured under the above conditions, and similarly, the 90% loss on heating temperature Tc90 refers to the temperature at which 90% of the weight is reduced from the initial sample amount.

In the present invention, the blending amount of the polyamide resin (a) is 65 to 99.8 parts by weight, preferably 80 to 98 parts by weight, when the total of (a) to (c) is 100 parts by weight. Preferably it is 90 to 96 parts by weight. The compounding amount of the layered silicate (b) is 100 in total of (a) to (c).
0.1 to 20 parts by weight, preferably 1 part by weight
10 to 10 parts by weight, more preferably 2 to 5 parts by weight. If the blending amount of the polyamide resin is too small, the mechanical properties inherent in the polyamide resin are impaired. If the blending amount is too large, the effect of improving the mechanical strength by adding the layered silicate becomes small, and neither is preferable.

The amount of the organic onium salt (c) is from (a) to
When the total of (c) is 100 parts by weight, 0.1 to 1
5 parts by weight, preferably 1 to 10 parts by weight, more preferably 2 to 5 parts by weight. The amount of the organic onium salt (c) with respect to the phyllosilicate (b) is usually in the range of 0.4 to 2.0 equivalents to the cation exchange capacity of the phyllosilicate, but 0.8 to 1 equivalent. It is preferably 2 equivalents. If the amount of the organic onium salt is too small, the effect of finely dispersing the layered silicate is small, and if the amount is too large, the amount of gas increases and the effect on the mechanical properties is undesirably large.

The composition of the present invention comprises a polyamide resin (a)
It is produced by adding an organic onium salt (c) when melt-kneading the layered silicate (b). The kneading method is not particularly limited as long as the mechanical shearing can be performed in a molten state of the polyamide resin. The processing method may be either a batch method or a continuous method, but a continuous method capable of continuous production is preferable from the viewpoint of working efficiency. Although there is no particular limitation on the specific device, an extruder, particularly a twin-screw extruder, is preferable in terms of productivity.

The order of addition of each component is (a), (b),
It is preferable to simultaneously supply each component of (c) to the melt kneading apparatus. In a method in which the three components (a), (b), and (c) are preblended and then supplied to the melt kneading apparatus, or in a continuous apparatus, It is preferable that the three components (a), (b) and (c) are supplied from the same feed port.

A specific method of adding the polyamide resin (a), the layered silicate (b), and the organic onium salt (c) is a known mixer used for mixing powder such as a Henschel mixer, a V blender, and a tumbler mixer. And then supplying the components to a melt-kneading apparatus, or individually supplying each component to an extruder using a quantitative feeder or the like.

In the case of melt kneading, (a), (b), (c)
It is preferable that each of the components is in a dry state, but the layered silicate (b) and the organic onium salt (c) are not foamed at the time of melt-kneading or have a water content not high enough to hydrolyze the polyamide resin. There is no problem even if water is absorbed.

In the present invention, the temperature at the time of melt-kneading is not lower than the 10% heating loss temperature of the organic onium salt (c) and 90%.
It is necessary to maintain the heating loss temperature or lower, and it is preferable to maintain the organic onium salt (c) at a temperature of 30% or more and 70% or less. When the melt-kneading temperature is lower than the 10% heating weight loss temperature of the organic onium salt (c) or higher than the 90% heating weight loss temperature, the lamellar silicate cannot be finely dispersed in any case, and the mechanical properties of the obtained composition are not improved. Physical properties decrease.

In the composition of the present invention, it is preferable that a layered silicate exfoliated to a single layer level is present. The monolayer level means that the layered silicate has a monolayer to about 10 layers,
It means that they are dispersed without secondary aggregation. This condition can be confirmed by cutting a section from the composition of the present invention and observing the section with an electron microscope. Further, the polyamide resin composition of the present invention includes various commonly used additives within a range not impairing the object of the present invention, for example, glass fiber, carbon fiber, acicular inorganic filler such as acicular wollastenite, glass flake, talc. , Kaolin, mica and other plate-like inorganic fillers, impact modifiers such as various elastomers, crystal nucleating agents, anti-coloring agents, antioxidants such as hindered phenols and hindered amines, ethylene bisstearyl amide and higher fatty acid esters, etc. Additives such as a release agent, a plasticizer, a heat stabilizer, a lubricant, an ultraviolet ray inhibitor, a colorant, and a flame retardant.

The polyamide resin composition of the present invention can be easily formed into a molded product by ordinary processing methods such as extrusion molding and injection molding. Further, it can be formed into a film, a sheet, a tube, a multifilament, a monofilament or the like. The resulting molded product shows a high flexural modulus with a small amount of filler, so various engineering parts,
Suitable for structural materials.

Examples of specific applications include various gears, various cases, sensors, connectors, sockets, resistors,
Electrical and electronic components such as relay cases, switch coil bobbins, housings, and computer-related components VTRs, TVs, irons, hair dryers, rice cookers, microwave ovens, audio equipment, lighting equipment, refrigerators, air conditioners, typewriters, word processors, etc. Home, office electrical product parts, oilless bearings, stern bearings, underwater bearings, etc., motor parts, lighters, typewriters, various bolts and nuts, power tool housings, bicycles, tricycles, snowmobiles, etc. Machine-related parts such as wheels Alternator terminal, alternator connector, IC regulator, potentiometer base for light deer, various valves such as exhaust gas valve, fuel related, exhaust system, intake system various pipes, air intake nozzle Nokeru, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor,
Cooling water sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake butt wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine holder In, wiper motor related parts, dust distributor, starter switch, starter relay, wire harness connector, window washer nozzle, air conditioner panel switch board, fuel related electromagnetic valve coil, fuse connector, horn terminal, electrical component insulating plate, step Motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, Jin oil filter, ignition device case, relay box, junction box, wheel cap, clip, fastener, engine covers, cylinder head cover, timing belt cover,
Examples include automobile and vehicle-related parts such as radiator tanks, underfloor supports, adjusters for adjusting the floor surface, building materials such as sash door rollers, and furniture-related parts such as chair legs.

[0036]

The present invention will be described in more detail with reference to the following examples.

The polyamide resins used in the examples are as follows.

Nylon 6: concentrated sulfuric acid, concentration 1%, 25
Nylon 66: concentrated in sulfuric acid at a concentration of 1%, relative viscosity 2.75 DSC measured at 25 ° C. Melting point 265 ° C. Used in Examples The organic onium salts thus obtained are as shown in Table 1. The loss on heating was measured at a heating rate of 20 ° C./min in a nitrogen atmosphere using a thermogravimeter (Seiko Denshi Kogyo: TG / DTA200 type).

[0039]

[Table 1]

Example 1 95.8 parts by weight of nylon 6 pellets, 3 parts by weight of synthetic mica (COPE Chemical: ME-100, cation exchange capacity 100 m equivalent / 100 g) powder, benzyl dimethyl stearyl ammonium chloride (Tokyo Kasei: Reagents) ) 1.2 parts by weight of the powder was stirred and mixed with a tumbler mixer to obtain a mixture. This mixture was melt-kneaded at a resin temperature of 250 ° C. using a PCM-30 type twin screw extruder (manufactured by Ikegai Iron and Steel) to obtain composition pellets.

After the obtained pellets were dried, they were injection-molded at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C.
No. dumbbell specimen (1/8 "thick) and 1/2" x
It was molded into a 5 ″ × １ ／ ″ thick rod-shaped test piece.

Using an ASTM No. 1 dumbbell-shaped test piece,
When the tensile strength was measured according to the STM D638 method, it was found to be 91 MPa. Also, using a bar-shaped test piece, AS
As a result of performing a bending test according to the TMD790 method, the bending strength was 120 MPa and the flexural modulus was 3.9 GPa. Further, when an ultrathin section was cut from the rod-shaped test piece and observed with a transmission electron microscope (TEM) to examine the dispersion state of the layered silicate, a large number of silicate single-layer dispersions were confirmed.

Example 2 Melt kneading was carried out in the same manner as in Example 1 except that in place of synthetic mica, Na-type montmorillonite (Kunimine Industries: Kunipia F, cation exchange capacity: 120 m equivalent / 100 g) was used. After obtaining the composition pellets and injection molding,
An evaluation was performed. The results are shown in Table 2.

Example 3 In the same manner as in Example 1, 94 parts by weight of nylon 6 pellets, 4 parts by weight of the same synthetic mica used in Example 1, and 2 parts by weight of trioctylmethylammonium chloride (Tokyo Kasei: reagent) were used. The composition was melt-kneaded to obtain a composition pellet, which was evaluated after injection molding. The results are shown in Table 2.

Example 4 An example using 95.7 parts by weight of nylon 66 pellets, 3 parts by weight of the same synthetic mica used in Example 1, and 1.3 parts by weight of dimethyl distearyl ammonium chloride (Tokyo Kasei: reagent). In the same manner as in Example 1, the mixture was melt-kneaded at a resin temperature of 280 ° C. to obtain a composition pellet.

The obtained pellets were dried, injection-molded at a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C., and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0047]

[Table 2]

REFERENCE EXAMPLE 1 Nylon 6 pellets (95.8 parts by weight), the same synthetic mica as used in Example 1 (3 parts by weight), and trimethylstearyl ammonium chloride (1.2 parts by weight) were used. The mixture was melt-kneaded at a temperature of 240 ° C. to obtain a composition pellet. Evaluation was performed after injection molding as in Example 1.
As shown in Table 3, the effect of improving strength and elastic modulus was small.

REFERENCE EXAMPLE 2 94 parts by weight of nylon 66 pellets, 4 parts by weight of the same synthetic mica as used in Example 1, and 2 parts by weight of trioctylmethylammonium chloride were used. The mixture was melt-kneaded to obtain a composition pellet.

The obtained pellets were dried, injection-molded at a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C., and evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 1 Only the polyamide and the layered silicate were mixed at the compounding ratio shown in Table 3.
The composition was melt-kneaded in the same manner as in Example 1 to obtain a composition, which was evaluated.
The results are shown in Table 3.

Comparative Example 2 A composition was obtained by melt-kneading only a polyamide and an organic onium salt in the mixing ratio shown in Table 3 in the same manner as in Example 1 to obtain a composition. The results are shown in Table 3.

[0053]

[Table 3]

[0054]

According to the present invention, a resin composition having excellent mechanical properties can be easily obtained. In particular, a resin composition having excellent rigidity such as flexural modulus can be obtained even with a small amount of inorganic ash. It is suitable for molded products such as automobile parts, electric / electronic parts, building materials, furniture, and daily necessities.

Claims (5)

[Claims] (1) When the total of the following (a) to (c) is 100 parts by weight, (a) 65 to 99.8 parts by weight of a polyamide resin (b) 0.1 to 20 parts by weight of a layered silicate (c) ) A polyamide resin composition obtained by melt-kneading 0.1 to 15 parts by weight of an organic onium salt. 2. The polyamide resin (a) has a melting point of Ta, and the organic onium salt (c) has a 10% heating loss temperature of Tc10, 90.
2. The polyamide resin composition according to claim 1, wherein the relationship of Tc10 <Ta + 20 <Tc90 is satisfied when the% heating loss temperature is Tc90. 3. The polyamide resin composition according to claim 1, wherein part or all of the layered silicate (b) is dispersed in the polyamide resin (a) at a single layer level. 4. Kneading (a) 65 to 99.8 parts by weight of a polyamide resin; (b) 0.1 to 20 parts by weight of a layered silicate at a melting temperature or higher of the polyamide resin; 1 to 15 parts by weight is added (provided that the total of (a) to (c) is 100 parts by weight), and the organic onium salt is heated at a temperature range of 10% or more and 90% or less. A method for producing a polyamide resin composition, comprising melt-kneading. 5. The process for producing a polyamide resin composition according to claim 4, wherein part or all of the layered silicate (b) is dispersed in the polyamide resin (a) at a single layer level.