JPH09241505A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide resin compsn. which has good mechanical properties and heat resistance and can provide a molded article very excellent in appearance by compounding a crystalline polyamide contg. a specific mica mineral with an amorphous polyamide. SOLUTION: This compsn. comprises 98-70 pts.wt. crystalline polyamide contg. 0.01-30wt.% swellable fluoromica mineral and 2-30 pts.wt. amorphous polyamide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention comprises a crystalline polyamide containing a swelling fluoromica-based mineral and an amorphous polyamide, and has good mechanical properties, heat resistance and the like, and
The present invention relates to a polyamide resin composition capable of forming a molded article having a remarkably excellent appearance.

[0002]

Polyamide is an engineering plastic excellent in mechanical strength, heat resistance, chemical resistance, etc., and is widely used as parts for automobiles, home electric appliances, office equipment, connectors and the like. However, when used under more severe conditions such as parts in an automobile engine room, it is insufficient in terms of rigidity and heat resistance.

Conventionally, a resin composition in which polyamide is reinforced with a fiber material such as glass fiber or carbon fiber or an inorganic filler such as calcium carbonate is widely known. However, these reinforcing materials do not have sufficient affinity with polyamide, and although the mechanical strength and heat resistance of the reinforced polyamide are improved, the toughness decreases, and in the resin composition reinforced with a large amount of fibrous material, molding is performed. There was a problem that the sled of the product became large. In addition, the resin composition reinforced with these inorganic fillers has a problem that the appearance of the obtained molded article is deteriorated.

As an attempt to improve the drawbacks of such a reinforced polyamide, for example, JP-A-62-74957 and JP-A-63-74957.
-230760, JP-A-1-301750, and 2-866
28 and 3-7729 propose a resin composition comprising a polyamide and a clay mineral represented by montmorillonite.

These resin compositions are intended to form finely and uniformly dispersed composites by infiltrating polyamide chains between layers of clay minerals, and when montmorillonite is used for such purpose, each of the above As described in the publication, it is essential to treat the montmorillonite with a swelling agent such as an amino acid before blending the montmorillonite with the polyamide or the monomer forming the polyamide so as to increase the interlayer distance of the montmorillonite. It was Therefore, there has been a strong demand in the art for an inorganic filler that does not require such a treatment and can solve the drawbacks of conventional reinforced polyamides.

As an attempt to solve such problems,
The present inventors have found that a resin composition comprising a crystalline polyamide and a swelling fluoromica-based mineral provides a molded article having excellent mechanical strength, toughness, heat resistance and dimensional stability, and previously. A patent application (Japanese Patent Laid-Open No. 6-248176)
It cannot be said that the obtained molded product has a sufficient appearance.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a polyamide resin composition which is excellent in mechanical properties, heat resistance and the like and can be formed into a molded article having a remarkably excellent appearance. .

[0008]

Means for Solving the Problems As a result of intensive studies to solve such problems, the present inventors have found that a crystalline polyamide containing a swellable fluoromica mineral and an amorphous polyamide are used. It has been found that this object can be achieved by blending the above.

That is, the present invention is a crystalline polyamide 98-70 containing 0.01-30% by weight of a swelling fluoromica-based mineral.
The gist is a polyamide resin composition comprising 2 parts by weight of amorphous polyamide and 2 to 30 parts by weight of amorphous polyamide.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The crystalline polyamide in the present invention means a melt-moldable polymer having an amide bond formed from an amino acid, a lactam or a diamine and a dicarboxylic acid.

The following are examples of monomers forming such a polyamide.

As the amino acid, 6-aminocaproic acid,
11-aminoundecanoic acid, 12-aminododecanoic acid, para-aminomethylbenzoic acid and the like.

As the lactam, ε-caprolactam, ω
-Laurolactam and the like.

Examples of diamines are tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylene. Diamine, 2,4-
Dimethyloctamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 3,8-bis ( Aminomethyl) tricyclodecane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, amino Ethyl piperazine and the like.

Examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and diglycolic acid.

As a preferable example of the crystalline polyamide,
Polycaproamide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612) , Polyundecamethylene adipamide (nylon 116), polyundecane amide (nylon 11), polydodecane amide (nylon 12), polybis (4-aminocyclohexyl) methandodecamide, (nylon PACM
12), polybis (3-methyl-4-aminocyclohexyl) methandodecamide (nylon dimethyl PACM12), polymethaxylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylene hexa Examples include hydroterephthalamide (nylon 11T (H)), copolyamides of these, and mixed polyamides. Among them, nylon 6 and nylon 4
6, nylon 66, nylon 610, nylon 11, nylon 1
2 and their copolyamides and mixed polyamides are particularly preferred.

The relative viscosity of the crystalline polyamide in the present invention is not particularly limited, but phenol / tetrachloroethane = 60/40 (weight ratio) is used as a solvent, and the temperature is 25 ° C.
1.5-5.0 in relative viscosity measured under the condition of concentration of 1 g / dl
Is preferably within the range. If the relative viscosity is less than 1.5, the mechanical properties of the molded product deteriorate, which is not preferable. On the other hand, when it exceeds 5.0, the moldability of the resin composition is rapidly lowered, which is not preferable.

The swellable fluoromica mineral in the present invention is represented by the following formula. α (MF) · β (aMgF ₂ · bMgO) · γSiO ₂ (where M represents sodium or lithium, α, β,
γ, a, and b each represent a coefficient, and 0.1 ≦ α ≦ 2, 2 ≦ β
≦ 3.5, 3 ≦ γ ≦ 4, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, a + b
= 1. )

As a method for producing such a swelling fluoromica-based mineral, for example, oxides such as silicon oxide, magnesium oxide, aluminum oxide and various fluorine compounds are mixed, and the mixture is placed in an electric furnace or a gas furnace. 1400-1500
There is a so-called melting method in which a fluoric mica-based mineral is completely melted at a temperature of ℃ and crystal-grown in a reaction vessel in the cooling process.

There is also a method in which talc is used as a starting material and alkali metal ions are intercalated into the starting material to obtain a fluoromica-based mineral (JP-A-2-149415). In this method, talc is mixed with an alkali metal silicofluoride or an alkali metal fluoride and mixed in a magnetic crucible.
By performing a short heat treatment at 00 to 1200 ° C., a swellable fluoromica-based mineral can be obtained. The swellable fluoromica-based mineral in the present invention is particularly preferably one produced by this method.

In order to obtain the above-mentioned swelling fluoromica-based mineral, it is necessary to use sodium or lithium as the alkali silicofluoride or the alkali metal in the alkali fluoride. These alkali metals may be used alone or in combination. Among the alkali metals, potassium is not preferable because it does not give a swelling fluoromica mineral, but it may be used in combination with sodium or lithium and may be used for the purpose of adjusting the swelling property in a limited amount. It is possible. The amount of alkali silicofluoride or alkali fluoride mixed with talc is
The range of 10 to 35% by weight of the total mixture is preferable, and if it is out of this range, the production yield of the swellable fluoromica-based mineral decreases.

The term "swelling property" as used in the present invention means that the fluoromica-based mineral absorbs polar molecules such as amino acids, nylon salts, water molecules and the like or cations between the layers to increase the interlayer distance, or further swelling and cleavage. , That is, the property of forming ultrafine particles. The fluoromica-based mineral represented by the formula exhibits such swelling property.

The preferred size of the swelling fluoromica mineral is 15 μm or less on one side, more preferably 10 μm or less, and the layer thickness in the c-axis direction measured by the X-ray powder method is 9 to 20 Å.

Further, in the step of producing the swellable fluoromica-based mineral, it is possible to blend a small amount of alumina to adjust the swelling property of the swellable fluoromica-based mineral produced.

In the present invention, various methods can be used to disperse the swellable fluoromica-based mineral in the crystalline polyamide, but the swellable fluoromica-based mineral is added to the monomer forming the crystalline polyamide. A method of polymerizing the monomer in the presence of a predetermined amount is particularly preferable. In this case, the swelling fluoromica-based mineral is sufficiently finely and uniformly dispersed in the crystalline polyamide, and the effect of the present invention is most remarkable.

The content of the swellable fluoromica-based mineral should be 0.01 to 30% by weight of the total mixture of the crystalline polyamide and the swellable fluoromica-based mineral, and should be 0.01 to 25% by weight. Is more preferable. If the content is less than 0.01% by weight, the effect of improving mechanical strength, heat resistance and dimensional stability will not be obtained, and if it exceeds 30% by weight, the toughness will be greatly reduced, which is not preferable.

The amorphous polyamide in the present invention is a polyamide having a heat of fusion of 1 cal / g or less when measured with a differential scanning calorimeter at a temperature rising rate of 16 ° C./min in a nitrogen atmosphere. Examples of such an amorphous polyamide include a polycondensate of isophthalic acid / terephthalic acid / hexamethylenediamine, and a polycondensate of isosophthalic acid / terephthalic acid / hexamethylenediamine / bis (3-methyl-4-aminocyclohexyl) methane. Condensate, isophthalic acid /
2,2,4-Trimethylhexamethylenediamine / 2,4,4-
Polycondensation product of trimethylhexamethylenediamine, terephthalic acid / 2,2,4-trimethylhexamethylenediamine /
Polycondensate of 2,4,4-trimethylhexamethylenediamine, isophthalic acid / terephthalic acid / 2,2,4-trimethylhexamethylenediamine / polycondensate of 2,4,4-trimethylhexamethylenediamine, isophthalic acid / Screw (3-
There are polycondensates of methyl-4-aminocyclohexyl) methane / ω-laurolactam, polycondensates of terephthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-laurolactam, and the like. In addition, those in which the benzene ring of the terephthalic acid component and / or the isophthalic acid component constituting these polycondensates is substituted with an alkyl group or a halogen atom are also included. Furthermore, two or more kinds of these amorphous polyamides can be used together.

It is necessary that the content of the amorphous polyamide is 2 to 30 parts by weight with respect to 98 to 70 parts by weight of the crystalline polyamide containing 0.01 to 30% by weight of the swelling fluoromica-based mineral. More preferably 5 to 20 parts by weight. If the content is less than 2 parts by weight, the effect of improving the appearance of the molded product is not sufficient, and if it exceeds 30 parts by weight, the appearance is improved, but the mechanical strength and heat resistance are remarkably reduced, which is not preferable. .

The resin composition of the present invention may further contain other polymers as long as the characteristics are not significantly impaired. Examples of such polymers include butadiene / styrene copolymers, styrene copolymers such as acrylonitrile / butadiene / styrene copolymers, polycarbonates,
Polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, polyether sulfone, polyether ketone, polyether ether ketone, polyetherimide, polyphenylene sulfide, polymethylmethacrylate, polyvinyl chloride, phenoxy resin, liquid crystal polymer, polyolefin and the like. To be At this time, the blending amount of the polymer is 30% of the whole resin composition.
% By weight or less.

Further, if necessary, pigments, heat stabilizers, antioxidants, weather resistance agents, flame retardants, plasticizers, mold release agents, lubricants, foaming agents, antistatic agents, moldability improving agents, reinforcing agents, etc. It can also be added. As heat stabilizers and antioxidants, hindered phenols, phosphorus compounds, hindered amines,
Examples thereof include sulfur compounds and copper compounds. Examples of the weather resistance agent include benzophenones and benzotriazoles. Examples of the flame retardant include phosphorus-based flame retardants and halogen-based flame retardants. Further, as a reinforcing material, clay,
Talc, calcium carbonate, zinc carbonate, wollastonite,
Silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, aluminum hydroxide, calcium hydroxide, barium sulfate, potassium alum, sodium alum, iron alum, glass balloon , Carbon black, zinc oxide, antimony trioxide,
Boric acid, borax, zinc borate, zeolite, hydrotalcide, metal fiber, metal whiskers, ceramic whiskers, potassium titanate whiskers, boron nitride,
Mica, graphite, glass fiber, carbon fiber and the like can be mentioned, but in the present invention, when the glass fiber is blended within a range that does not impair the appearance, rigidity and heat resistance when formed into a molded body is an economical method. It is more preferable because it can be improved.

The polyamide resin composition of the present invention comprises a Banbury mixer, a roll mixer, a kneader, a single screw extruder,
It can be produced using a conventionally known melt-kneading device such as a multi-screw extruder. At this time, the melt-kneading temperature is 250 to 300.
The temperature is preferably in the range of 0 ° C, and the melt-kneading time depends on the temperature and the melt-kneading apparatus used, but is usually 1 to 30.
It is preferably in the range of minutes. Further, as a method for supplying the components constituting the resin composition of the present invention to the melt-kneading device, all the constituent components may be supplied at once, or the components constituting the resin composition may be supplied from different supply ports. It may be supplied in multiple stages such as supplying.

Further, the polyamide resin composition of the present invention can be made into a desired molded article by a usual molding processing method. For example, a method of forming a molded article by a hot melt molding method such as injection molding, extrusion molding, blow molding, sinter molding, or a casting method from an organic solvent solution can be adopted.

[0034]

Next, the present invention will be described more specifically with reference to examples. The raw materials and measuring methods used in Examples and Comparative Examples are as follows.

1. Raw material (1) Swellable fluoromica mineral: 20% by weight of the total amount of sodium fluorosilicate having an average particle size of 2 μm with respect to talc crushed by a ball mill so that the average particle size becomes 2 μm
The resulting mixture was mixed in a magnetic crucible and kept in an electric furnace at 800 ° C for 1 hour to synthesize a fluoric mica-based mineral. As a result of measuring the formed fluoromica-based mineral by an X-ray powder method, the peak corresponding to the thickness 9.2Å in the c-axis direction of the raw material talc disappeared, indicating the formation of a swellable fluoromica-based mineral 12
A peak corresponding to ~ 16Å was observed. The average particle size of this swellable fluoromica mineral was 1.8 μm. Talc: Mg ₃ SiO ₄ O ₁₀ (OH) ₂ Sodium fluorosilicate: Na ₂ SiF ₆ (2) Amorphous polyamide (a) Grivory XE-3080 (Grivory XE-3080): isophthalic acid / terephthalic acid / hexamethylene Polycondensation product of diamine / bis (3-methyl-4-aminocyclohexyl) methane (manufactured by Ems) (b) Trogamid T: terephthalic acid / 2,2,
Polycondensation product of 4-trimethylhexamethylenediamine / 2,4,4-trimethylhexamethylenediamine (manufactured by Dynamit Nobel) (c) Grilamide TR-55 (Grilamid TR-55): isophthalic acid / bis (3- Methyl-4-aminocyclohexyl) methane / ω-laurolactam polycondensate (manufactured by Ems)

2. Measurement method (1) Flexural modulus Based on ASTM D790, thickness adjusted to absolute dryness 3.2 mm
The measurement was carried out using the test piece of (2) Heat distortion temperature Based on ASTM D648, using the above test piece, load 18.6 kg
It was measured at / cm ² . (3) Appearance The test pieces were visually observed. A: Very good appearance B: Good appearance C: Slightly bad appearance D: Poor appearance Note that A and B can be put to practical use.

Example 1 10 kg of ε-caprolactam was mixed with 2 kg of water and 0.35 kg of a swelling fluoromica mineral, placed in a reactor having an internal volume of 30 liters, and heated to 250 ° C. with stirring. while slowly releasing the water vapor to be boosted from 4 kg / cm ² to a pressure of 15 kg / cm ^2. After that, the pressure is released to ² kg / cm ² and 260
Polymerization was performed at 3 ° C. for 3 hours. At the end of the polymerization, the reaction product was discharged in a strand form, cooled and solidified, and then cut,
Then, it is treated with hot water at 95 ° C, scoured, and then dried under reduced pressure to obtain nylon 6 containing a swellable fluoromica-based mineral.
To obtain 9.85 kg of pellets (N-1). This N-1 contained 3.6% by weight of a swellable fluoromica-based mineral. The relative viscosity of the obtained nylon 6 is 2.64, and the concentrations of terminal amino group and carboxyl group are respectively
It was 56 equivalents / ton and 57 equivalents / ton. Next, using a twin-screw extruder (PCM-45, manufactured by Ikegai Tekko KK), 98 parts by weight of N was used.
-1, 2 parts by weight of amorphous polyamide Grivory XE-3
080, and 43 parts by weight of glass short fibers (made by Nippon Electric Glass Co., Chopped Strand T-289, fiber diameter: 13 μm: fiber length: 3.2 mm) were melt-kneaded at 260 ° C. and extruded at the same temperature to form pellets. . After drying the pellets, injection molding was performed at a cylinder temperature of 260 ° C and a mold temperature of 80 ° C to obtain a thickness.
A 3.2 mm test piece was prepared and a physical property test was conducted. Table 1 shows the obtained results.

Examples 2 to 5 and Comparative Example 1 Test pieces were prepared in the same manner as in Example 1 except that the compounding amount of N-1 and the type and compounding amount of the amorphous polyamide were changed as shown in Table 1. It was produced and a physical property test was conducted. Table 1 shows the obtained results.
Shown in

[0039]

[Table 1]

Examples 6 to 8 and Comparative Example 2 Test pieces were prepared in the same manner as in Example 1 except that N-1 and Grivory XE-3080 were blended as shown in Table 2 without blending short glass fibers. It was produced and a physical property test was conducted. Table 2 shows the obtained results.

[0041]

[Table 2]

Example 9 10 kg of nylon 66 salt was mixed with 3 kg of water and 0.35 kg of swelling fluoromica mineral, put in a reactor having an internal volume of 30 liters, and heated to 230 ° C. with stirring. , The internal pressure is 18kg
It was heated at the same temperature until the / cm ^2. Next, while gradually releasing steam, the internal pressure was kept at 18 kg / cm ² and the temperature was raised, and when the temperature reached 280 ° C., the pressure was released to normal pressure, and further polymerization was carried out at the same temperature for 2 hours. At the end of the polymerization, the reaction product was discharged in a strand form, cooled and solidified, cut and dried under reduced pressure to obtain 9.26 kg of pellets (N-2) of nylon 66 containing a swellable fluoromica-based mineral. . This N-2 contained 3.8% by weight of a swellable fluoromica-based mineral. Further, the obtained nylon 66 had a relative viscosity of 2.70, and the concentrations of the terminal amino group and the carboxyl group were 50 equivalent / ton and 60 equivalent / ton, respectively. Next, using a twin-screw extruder (PCM-45, manufactured by Ikegai Tekko KK), 98 parts by weight of N-2 and 2 parts by weight of Grivory XE-3080 are used.
, And 43 parts by weight of glass short fibers were melt-kneaded at 270 ° C. and extruded at the same temperature to form pellets. After drying the pellets, injection molding was carried out at a cylinder temperature of 275 ° C. and a mold temperature of 80 ° C. to prepare a test piece having a thickness of 3.2 mm, and a physical property test was conducted. Table 3 shows the obtained results.

Examples 10 to 11 and Comparative Example 3 Test pieces were prepared in the same manner as in Example 9 except that the compounding amounts of N-2 and Grivory XE-3080 were changed as shown in Table 3, and the physical properties were tested. went. Table 3 shows the obtained results.

[0044]

[Table 3]

[0045]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a polyamide resin composition which is excellent in mechanical properties, heat resistance and the like and can be formed into a molded article having a remarkably excellent appearance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiteru Nagai 31-3 Uji Hinojiri, Uji City, Kyoto Prefecture Unitika Uji Plastic Factory

Claims (1)

[Claims] 1. A polyamide resin composition comprising 98 to 70 parts by weight of a crystalline polyamide containing 0.01 to 30% by weight of a swelling fluoromica mineral and 2 to 30 parts by weight of an amorphous polyamide.