JPH11217497A - Reinforced polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reinforced polyamide resin compsn. which is excellent in tensile strength, elongation, and thermal stability during molding without detriment to its good flexural moldulus by compounding a polyamide resin with a layered silicate contg. specific intercalated quaternary ammonim ions. SOLUTION: This compsn. contains 100 pts.wt. polyamide resin and 0.5-30 pts.wt. layered silicate contg. intercalated quaternary ammonium ions having oxyalkylene structures. Pref., the layered silicate has a cation exchange capacity of 30-300 meq/100 g. The amt. of the quaternary ammonium ions intercalated into the layered silcate is pref. 70-300% of the cation exchange capacity of the silicate. A pref. example of the quaternary ammonium ion is a dimethylbispolyoxyethyleneammonium ion having 1-30 repeating oxyethylene units. A swellable fluoromica is suitable as the layered silicate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a reinforced polyamide resin composition. More specifically, the present invention relates to a reinforced polyamide resin composition having excellent tensile strength, tensile elongation, and excellent thermal stability during molding while maintaining a good flexural modulus.

[0002]

2. Description of the Related Art In order to improve various properties, especially mechanical properties, of organic polymer materials such as thermoplastic resins, it has been practiced to add inorganic fillers such as talc, kaolinite, and mica. I have. However, simply melt-mixing these with the thermoplastic resin does not uniformly disperse the inorganic filler in the thermoplastic resin in a molecular state, and therefore, a thermoplastic resin composite having sufficiently satisfactory properties cannot be obtained.

Japanese Patent Publication No. 58-35211 discloses that in order to uniformly disperse a layered silicate in a polyamide resin in a molecular state, a silicate, particularly a layered silicate, is selected, and an amino acid or a polyamide is prepared in advance. After intercalating with an organic compound such as a salt, a monomer is polymerized in the presence of such a layered silicate to produce a reinforced polyamide resin composition in which the layered silicate is uniformly dispersed in a molecule. ing.

The term "intercalation" refers to the replacement of alkali or alkaline earth metal ions between layered silicate layers with target ions and insertion between the layers.
However, although the rigidity of the polyamide composite obtained by this method is improved by increasing the amount of the layered silicate,
There is a problem that the tensile elongation characteristic of the polyamide resin is significantly reduced.

[0005] In order to solve this problem, a collection of polymer papers; vol. 52, no. 7, p440 (1995) proposes a method of adding a diamine together with an amino acid in the process of intercalating a layered silicate with an organic compound to control the dispersion state of the layered silicate. However, in this method, rigidity and strength are reduced, and elongation is not sufficiently improved.

JP-A-8-12881 discloses that a quaternary ammonium ion having an alkyl group having 12 or more carbon atoms is used instead of an amino acid or a nylon salt.
It has been reported that elongation is improved with little loss in stiffness. However, the quaternary ammonium ions used in this method require a large amount of addition, and there is a risk that the thermal stability during molding may be reduced.

[0007]

The present invention relates to a reinforced polyamide resin composition in which a layered silicate is dispersed at a molecular level in a polyamide resin. More specifically, the present invention relates to a reinforced polyamide resin composition having a good tensile modulus while maintaining a good flexural modulus. An object of the present invention is to provide a reinforced polyamide resin composition having excellent strength, tensile elongation, and thermal stability during molding.

[0008]

As a result of various studies on organic compounds to be intercalated between layers of the layered silicate, the present inventors have found that the use of a specific ammonium ion as an organic compound provides a good flexural modulus. While maintaining the above, it was found that a reinforced polyamide resin composition having excellent tensile strength, tensile elongation, and thermal stability during molding was obtained, and the present invention was completed.

That is, the present invention is as follows. 1) A reinforced polyamide resin composition comprising 100 parts by weight of a polyamide resin and 0.5 to 30 parts by weight of a layered silicate intercalated with a quaternary ammonium ion having an oxyalkylene structure. 2) The layered silicate has a cation exchange capacity of 30 meq /
2. The reinforced polyamide resin composition according to the above item 1, which is a layered silicate of 100 g or more.

(3) The reinforced polyamide according to the above (1) or (2), wherein at least 70% of the cation exchange capacity of the layered silicate is intercalated with a quaternary ammonium ion having an oxyalkylene structure. Resin composition. (4) The reinforced polyamide resin composition according to the above (1), (2) or (3), wherein the layered silicate is swellable fluoromica.

Hereinafter, the present invention will be described in detail. Examples of the polyamide resin used in the present invention include polyamide 66 resin, polyamide 610 resin, and polyamide 612.
Resin, polyamide 6I (I is isophthalic acid) resin,
Polyamide 6T (T stands for terephthalic acid) resin, polyamide MXD6 (MXD stands for meta-xylylenediamine), polyamide 46 resin, polyamide 6 resin, polyamide 3 resin, polyamide 11 resin and polyamide 12
Examples thereof include resins and / or copolymers thereof.

The relative viscosity (ηr) of the polyamide resin is as follows.
A range of 5 to 3.5 is preferable, and a more preferable range of the relative viscosity (ηr) is 1.9 to 3.0. If the relative viscosity (ηr) is less than 1.5, the toughness may decrease. If the relative viscosity (ηr) exceeds 3.5, the fluidity may decrease and the appearance of the molded article may deteriorate. Further, the amino group as an end group of the polyamide resin is 20 to 90 meq / kg,
Preferably, the carboxyl group has a range of 20 to 100 meq / kg, and more preferably, the terminal group has an amino group of 40 to 70 meq / kg and a carboxyl group of 40 to 80 meq / kg. . If the amino group as the terminal group of the polyamide resin is less than 20 meq / kg, printability and dyeability may be reduced, and it is difficult to increase the molecular weight of a polyamide exceeding 90 meq / kg. If the carboxyl group is less than 20 meq / kg, the adhesion to the surface-treated inorganic filler or the like may be deteriorated. If the carboxyl group exceeds 100 meq / kg, the thermal stability may be deteriorated. Get higher.

The quaternary ammonium ion used in the present invention is a quaternary ammonium ion having an oxyalkylene structure. As such a quaternary ammonium ion, an ammonium ion having an oxyalkylene structure represented by the following general formula (a) can be preferably used.

[0014]

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(However, in the formula (a), R₁, R_Two, R_Three,
R_FourIs a carbon atom, hydrogen atom, oxygen atom, nitrogen atom, sulfur
Represents a molecular structure composed of atoms and the like;₁, R_Two, R
_Three, R _FourContains an oxyalkylene structure. This
Where R₁, R_Two, R_Three, R_FourAre different from each other
Or the same. ) More preferred quaternary ammonium ions include those of the formula
R in (a)₁, R_Two, R _Three, R_FourOne or more of the following
Having a structure represented by the general formula (b) or (c)
You.

[0016]

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(However, in the formulas (b) and (c), X ₁ ,
X ₂ , R ₅ and R ₆ each represent a molecular structure composed of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, and the like;
_1, X ₂ may be omitted. Also, m ₁ and m ₂ are 1
Represents the above integer. As a more preferred quaternary ammonium ion, at least _two of R ₁ , R ₂ , R ₃ and R _{4 in} the formula (a) have the structure of the formula (b) or the formula (c), and further have the formula (b) ) Or (c), R ₅ and R ₆ are hydrogen atoms, m ₁ and m ₂ are in the range of 1 to 30, and have a molecular structure free of X ₁ and X ₂ .

There is a high possibility that a quaternary ammonium ion containing no oxyalkylene structure cannot exhibit sufficient tensile elongation, and the thermal stability during molding may be deteriorated.
Specific examples include dimethylbispolyoxyethyleneammonium ion, diethylbispolyoxyethyleneammonium ion, dibutylbispolyoxyethyleneammonium ion, methylethylbispolyoxyethyleneammonium ion, methylbutylbispolyoxyethyleneammonium ion, and ethyl. Quaternary ammonium ions having two polyoxyethylene groups in one molecule such as butylbispolyoxyethyleneammonium ion, methylhexylbispolyoxyethyleneammonium ion, and methyloctylbispolyoxyethyleneammonium ion; dimethylbispolyoxypropyleneammonium Ion, diethyl bispolyoxypropylene ammonium ion, dibutyl bis polyoxypropylene ammonium ion Polyoxypropylene groups such as methyl ethyl bis polyoxy propylene ammonium ion, methyl butyl bis polyoxy propylene ammonium ion, ethyl butyl bis polyoxy propylene ammonium ion, methyl hexyl bis polyoxy propylene ammonium ion, and methyl octyl bis polyoxy propylene ammonium ion Having two in one molecule
Secondary ammonium ion and the like.

Furthermore, dimethyl polyoxyethylene polyoxypropylene ammonium ion, diethyl polyoxyethylene polyoxypropylene ammonium ion, dibutyl polyoxyethylene polyoxypropylene ammonium ion, methyl ethyl polyoxyethylene polyoxypropylene ammonium ion, methyl butyl polyoxy ammonium Polyoxyethylene and polyoxypropylene groups such as ethylene polyoxypropylene ammonium ion, ethylbutyl polyoxyethylene polyoxypropylene ammonium ion, methylhexyl polyoxyethylene polyoxypropylene ammonium ion, and methyl octyl polyoxyethylene polyoxypropylene ammonium ion Having one in each molecule
Secondary ammonium ion and the like.

Among them, dimethyl bispolyoxyethylene ammonium ion, diethyl bis polyoxyethylene ammonium ion, dibutyl bis polyoxyethylene ammonium ion, dimethyl bis polyoxypropylene ammonium ion, diethyl bis polyoxypropylene ammonium ion, dibutyl bis polyoxypropylene ammonium Ammonium ions having two polyoxyethylene groups or polyoxypropylene groups such as ammonium ions in one molecule are preferred from the viewpoint of tensile elongation retention and thermal stability of the reinforced polyamide resin composition, more preferably,
The repeating unit of oxyethylene is a dimethylbispolyoxyethylene ammonium ion having 1 to 30 oxypropylene, and the repeating unit of oxypropylene is 1 to 30 dimethylbispolyoxypropylene ammonium ion.

Incidentally, these quaternary ammonium ions can be used alone or as a mixture of plural kinds. The amount of the quaternary ammonium ion intercalated into the layered silicate is preferably in the range of 70 to 300%, more preferably 90 to 300%, based on the cation exchange capacity of the layered silicate.
It is in the range of -200%, more preferably in the range of 99-150%. When the intercalation amount of the quaternary ammonium ion is less than 70% of the phyllosilicate cation exchange capacity, the lamellar silicate is difficult to be uniformly dispersed in the polyamide resin in a molecular form, and when it exceeds 300%, the molding efficiency is increased. May have poor thermal stability.

In the raw material stage, the quaternary ammonium ion used in the present invention is usually handled as a salt with a halide ion. The layered silicate used in the present invention is a layered phyllosilicate composed of a magnesium silicate or aluminum silicate layer, specifically,
Montmorillonite, swellable fluoromica, saponite, beidellite, hectorite, stevensite, vermiculite, halloysite, etc. can be exemplified, preferably montmorillonite, swellable fluoromica, more preferably bending of the polyamide composite Elastic modulus,
From the viewpoint of improving tensile strength and avoiding coloring, it is a swellable fluoromica. These may be synthetic or natural.

The layered silicate is more preferably a highly purified layered silicate of 95% or more obtained from a naturally occurring layered silicate or a synthesized layered silicate. In the case of swellable fluoromica, talc or silica fluoride is preferable. Those synthesized in the solid phase using sodium chloride and / or lithium silicofluoride as a raw material are more preferable. The layered silicate has a water swelling property, and the cation exchange capacity of the layered silicate is 30 to 300 meq / l.
00g is preferred, and more preferably 60 to 300 meq / 100g. If the cation exchange capacity is less than 30 meq / 100 g, the layered silicate does not sufficiently swell in the polymer, so that it is difficult to uniformly and molecularly disperse it in the polyamide resin.
Layered silicates exceeding 0 g are hardly present in nature or are industrially difficult to synthesize.

In the present invention, the layered silicate preferably contains an alkali or alkaline earth metal ion between layers, and these ions are preferably Na ⁺ ions or Li ⁺ ions. These interlayer ions are ion-replaced with ammonium ions and mixed with a polyamide monomer or polyamide resin. The shape of the layered silicate used in the present invention has a layered crystal structure, and the length of one side of the layer is preferably in the range of 10 to 1000 nm on average, and the thickness of one layer is preferably 6 to 10 °. .

The layered silicate used in the present invention has an average particle size of 1 μm or less, preferably 0.1 μm or less, in the polyamide resin.
It is preferable that 50% by weight or more thereof is uniformly dispersed at a distance of 2 nm or more in the range of 7 to 500 nm on average. The amount of the layered silicate added is 0.5 to 30 parts by weight, preferably 1 to 10 parts by weight, and more preferably 2 to 5 parts by weight based on 100 parts by weight of the polyamide resin. If the addition amount is less than 0.5 part by weight, the effect of improving rigidity is insufficient, and if it exceeds 30 parts by weight, it becomes difficult to uniformly disperse the layered silicate in a molecular state.

The reinforced polyamide resin composition may be, if necessary, a resin other than polyamide, a dye, a pigment, a fibrous reinforcement (glass fiber, carbon fiber, etc.), a particulate reinforcement, a release agent, a thickener, etc. Moldability improvers, plasticizers,
A lubricant, an impact resistance improving agent, a foaming agent, a heat resistance improving agent, a weathering agent, a flame retardant, a nucleating agent and the like can be blended. As resins other than polyamide resins, for example, polyethylene, polypropylene, polystyrene, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin, styrene-butadiene block copolymer and hydrogenated products thereof, thermoplastic polyester, polymethyl methacrylate, polycarbonate , Polyphenylene ether, polyoxymethylene, polyphenylene sulfide, polysulfone, polyethersulfone, polyetherimide, polyetheretherketone, and the like.

When these resins are mixed with a polyamide resin composite material, two or more kinds may be used in combination. When these resins are mixed with a polyamide resin composite material, in the case of a combination incompatible with a polyamide resin, a compatibilizer can be blended. As the compatibilizer, conventionally known compatibilizers can be widely used.

The reinforced polyamide resin composition of the present invention may be a mixture with a resin other than the polyamide resin as long as it contains at least 10% by weight, preferably at least 20% by weight of the polyamide resin. As a method of producing the polyamide resin composition of the present invention, a method of adding a layered silicate to a polyamide monomer and polymerizing the same (polymerization method);
A method in which a polyamide resin and a layered silicate are blended and then melt-kneaded (a melt-kneading method) is preferable. In the polymerization method,
A layered silicate obtained by intercalating a quaternary ammonium ion into a polyamide monomer is mixed and stirred. The temperature is increased while stirring the layered silicate in a state where the layered silicate is dispersed in the polyamide monomer in advance, and the dehydration and polymerization reactions are performed. It is preferable to carry out while flowing nitrogen gas. Further, as a melt kneading method, a twin screw extruder having two or more zones for improving kneading (screw using parts for increasing compression, shearing, and diverting, such as a screw having a shallow groove, a kneading disk, etc.) is provided. It is preferred to use and melt-knead while degassing.

The reinforced polyamide resin composition of the present invention can be prepared by a known method generally used for molding a thermoplastic resin,
For example, it is molded into various molded articles by a method such as injection molding, blow molding, inflation molding, vacuum molding, extrusion molding, and heat and pressure molding.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, the intercalation method, the evaluation method, etc. are as follows. [Method of Intercalating Organic Compound into Layered Silicate] Five kinds (M-1 to 5) of layered silicate in which an organic compound was intercalated were prepared as described below.

50 g of the layered silicate shown in Table 1 was mixed and dispersed in 2 liters of water, and an organic compound shown in the same table was added thereto in an amount equivalent to 1.5 times the cation exchange capacity of the layered silicate.
The mixture was heated to 0 ° C. and stirred for 60 minutes. However, when the organic compound was not ionized like aminododecanoic acid, an aqueous solution of hydrochloric acid having a concentration of 35% was further added in an amount equivalent to 1.5 times the cation exchange capacity of the layered silicate.

Further, after performing suction filtration while sufficiently washing with water using a Buchner funnel, vacuum drying was performed at 80 ° C. for 48 hours to obtain a layered silicate in which sodium ions between layers were replaced with organic compounds. A dry solid lump was obtained, and the lump composite was pulverized to about 0.3 to 10 μm with a pulverizer to obtain a powder. Hereinafter, this powder is referred to as a treated layered silicate.

[0033]

[Table 1]

[Evaluation Items and Methods] (a) Dispersibility Ultra-thin sections of the resin composite pellets obtained by the methods of Examples and Comparative Examples were cut out, and the dispersibility was measured by JEOL Ltd.
Observed using a transmission electron microscope JEM1200. The evaluation with a transmission electron microscope was performed based on the following criteria.

：: Good dispersibility (50% or more of a layer having a thickness of 1 μm or less) ×: Poor dispersibility (a layer of less than 50% of a layer having a thickness of 1 μm or less) XX: Very poor dispersibility (Most exist in a lump of 1 μm or more) (b) Tensile strength and tensile elongation The resin composite materials obtained by the methods of Examples and Comparative Examples were manufactured by Nippon Steel Works Co., Ltd. using a J100SS-II molding machine. ASTM No. 3 dumbbell molded product was injection molded. This dumbbell-shaped molded article was evaluated for tensile strength according to ASTM D123.

(C) Flexural Modulus The resin composite material obtained by the method of Example and Comparative Example was injection-molded into an ASTM No. 3 strip-shaped molded product using a J100SS-II molding machine manufactured by Japan Steel Works, Ltd. did. This strip-formed body was evaluated for flexural modulus in accordance with ASTM D790. (D) Thermal stability during molding The resin composite materials obtained by the methods of Examples and Comparative Examples were injection-molded into ASTM No. 3 strip-shaped molded products using a J100SS-II molding machine manufactured by Japan Steel Works, Ltd. did. This strip-formed body was visually observed to confirm the presence or absence of air bubbles. ASTM
The flexural modulus was evaluated according to D790. In addition,
This evaluation was performed based on the following criteria.

：: No bubbles are present in the molded body ×: Bubbles are present in the molded body

[0038]

Examples 1 to 4 Polyamide 66 resin "Leona 130"
0 "(manufactured by Asahi Kasei Corporation), treated layered silicate,
Each was mixed in the kind and amount shown in Table 2, and melt-kneaded into pellets at a resin temperature of 295 ° C. using a twin screw extruder ZSK25 manufactured by Werner & Friedler to obtain polyamide resin composite material pellets. The pellets thus obtained were dried at 80 ° C. for 24 hours in a nitrogen flow atmosphere, and were subjected to predetermined evaluation.

Table 2 shows the results.

[0040]

Example 5 A polyamide 6 resin "1030B" (manufactured by Ube Industries, Ltd.) was used in place of the polyamide 66 resin, and the resin temperature during melt-kneading and pelletizing was 250 ° C. Test pieces were prepared and evaluated in the same manner as in Examples 1 to 4. Table 2 shows the results.

[0041]

Comparative Examples 1 to 4 Specimens were prepared and evaluated in the same manner as in Examples 1 to 4, except that the polyamide resin and the treated layered silicate were of the kind and amount shown in Table 3, respectively. .
Table 3 shows the results.

[0042]

[Table 2]

[0043]

[Table 3]

As is clear from Tables 2 and 3, the reinforced polyamide resin composition comprising the polyamide resin of the present invention and a layered silicate intercalated with a quaternary ammonium ion having an oxyalkylene structure was prepared using the conventional amino acid. Compared to a polyamide resin composite material comprising a polyamide resin and a layered silicate intercalated with a polyamide salt and a quaternary ammonium ion having an alkyl group having 12 or more carbon atoms, the tensile strength is maintained while maintaining a good flexural modulus. Excellent in tensile elongation and thermal stability during molding.

[0045]

The reinforced polyamide resin composition of the present invention comprises:
It has excellent tensile strength, tensile elongation and thermal stability during molding while maintaining good bending elastic modulus. The reinforced polyamide resin composition of the present invention is, for example, as an exterior part of an automobile, a wheel cover, a door mirror stay, a roof leg, a sunroof deflector, an instrument panel as an interior part of an automobile, a wire harness connector,
Tara radiator water pump impeller, wiper motor cover, canister, distributor cam, transmission thrust wire, bearing, rotary sealing, bush, door bushing, brake leader, seat roller, radiator tank, fuel tank, harness, connectors, Engine parts include engine covers, intake manifolds, cylinder head covers, shock absorber parts, etc. OA and electronic parts such as sockets, switches, fuse boxes, fuse cases, electric heater parts,
SMT connectors, connectors, copier parts. Other structural materials such as bicycle wheels, fishing gear reels, desk legs, chair legs, crescents (sash key covers), vehicle parts,
It is suitable for a wide range of uses such as daily necessities, toys, miscellaneous goods, and building material parts.

Claims (4)

[Claims] 1. A reinforced polyamide resin composition comprising 100 parts by weight of a polyamide resin and 0.5 to 30 parts by weight of a layered silicate intercalated with a quaternary ammonium ion having an oxyalkylene structure. 2. The layered silicate has a cation exchange capacity of 30.
The reinforced polyamide resin composition according to claim 1, which is a layered silicate having a milliequivalent / 100 g or more. 3. The reinforcement according to claim 1, wherein the layered silicate has at least 70% of its cation exchange capacity intercalated with a quaternary ammonium ion having an oxyalkylene structure. Polyamide resin composition. 4. The reinforced polyamide resin composition according to claim 1, wherein the layered silicate is swellable fluoromica.