JPH09111116A - Production of reinforced polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a reinforced polyamide resin composition reduced in the formation of bubbles and excellent in mechanical strengths toughness, heat resistance and dimensional stability by adding a swellable fluoromica mineral to polyamide-forming monomers and subjecting the mixture to a polymerization reaction. SOLUTION: Polyamide-forming monomers in an amount to give 100 pts.wt. polyamide and polymerized in the presence of 0.01-100 pts.wt. swellable fluoromica mineral, 0.1-9 pts.wt. water and 0.001-10 pts.wt. molecular weight modifier comprising a compound reactive with carboxyl or/and amino groups.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a reinforced polyamide resin composed of a polyamide resin and a specific swelling fluoromica-based mineral, which is excellent in mechanical strength, toughness, heat resistance and dimensional stability and has less entrainment of bubbles. The present invention relates to a method for producing a composition.

[0002]

2. Description of the Related Art Polyamide resins are widely used as injection molding materials for parts such as automobiles and electric products, because the molded products have excellent heat resistance and mechanical strength.

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 have a poor affinity with polyamide, and although the mechanical strength and heat resistance of the reinforced polyamide are improved, the toughness is reduced, and in the resin composition reinforced with fibrous material, the warpage of the molded product is There is a problem that it becomes large. Moreover, the resin composition reinforced with these inorganic fillers has a problem that the mechanical strength and heat resistance cannot be improved unless a large amount of the filler is blended.

As an attempt to improve the drawbacks of such a reinforced polyamide, a resin composition comprising a polyamide and a clay mineral typified by montmorillonite has been proposed (JP-A-62-74957, JP-A-1-74957). No. 301750 bulletin,
JP-A-2-86628 and JP-A-3-7729).

This resin composition is intended to form a composite in which polyamide chains are finely and uniformly dispersed by infiltrating polyamide chains between layers of clay minerals. When montmorillonite is used for such a 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 eliminate the drawbacks of conventional polyamide resins.

As an attempt to solve such problems,
The present inventors have previously proposed a method for producing a reinforced polyamide resin composition by adding a specific swelling fluoromica mineral to a polyamide-forming monomer and polymerizing the same (JP-A-6-248176). . According to this method, unlike the case of using a clay mineral typified by montmorillonite, a resin composition having excellent mechanical strength, toughness, heat resistance and dimensional stability can be obtained without performing a swelling treatment. It was

However, when these resin compositions are produced, as the amount of the swellable fluoromica-based mineral as a reinforcing material increases, a large amount of bubbles are generated during the polymerization, resulting in chips of the obtained resin composition. There was a problem that air bubbles were trapped inside.

It is considered that this is due to the fact that the swelling fluoromica-based mineral described above has a large hydrophilicity and therefore polymerizes in a state where a large amount of water is taken in. However, the use of chips with air bubbles entails poor moldability, making it difficult to obtain molded products with excellent performance and appearance.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a reinforced polyamide resin composition by adding a swelling fluoromica-based mineral to a monomer forming a polyamide to polymerize the same, and to reduce the occurrence of air bubbles An object of the present invention is to provide a method capable of obtaining a reinforced polyamide resin composition excellent in dynamic strength, toughness, heat resistance and dimensional stability.

[0010]

Means for Solving the Problems The present invention is intended to solve the above-mentioned problems, and the gist thereof is that 0.01 to 100 swelling fluoromica-based minerals are added to the amount of monomers forming 100 parts by weight of polyamide. Parts by weight, 0.1 to 9 parts by weight of water, and 0.001 to 10 parts by weight of a compound capable of reacting with a carboxyl group and / or an amino group as a molecular weight modifier, to polymerize a monomer in the presence thereof. It is in the manufacturing method of the thing.

[0011]

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

The polyamide in the present invention is an amino acid,
It means a melt-moldable polymer having an amide bond formed from a lactam or diamine and a dicarboxylic acid. Examples of the monomer that forms such a polyamide include the following.

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

As the lactam, ε-caprolactam, ω
-Laurolactam, etc.

As the diamine, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 2, 4-dimethyloctamethylenediamine,
Meta-xylylenediamine, para-xylylenediamine, 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, aminoethylpiperazine and the like.

Examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2
-Chloroterephthalic acid, 2-Methylterephthalic acid, 5-
Examples include methyl isophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and diglycolic acid.

Preferred polyamides in the present invention include 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), polydodecanamide (nylon 12), polytrimethylhexamethylene terephthalamide nylon TMHT),
Polyhexamethylene isophthalamide (nylon 6I),
Polyhexamethylene terephthal / isophthalamide (nylon 6T / 6I), polybis (1-aminocyclohexyl) methandodecamide (nylon PACM12), polybis (3-methyl-4-aminocyclohexyl) methandodecamide (nylondimethylPACM12), polymer Taxylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylene hexahydroterephthalamide (nylon 11T (H))
And copolyamides and mixed polyamides thereof. Of these, nylon 6 and nylon are especially preferred.
46, nylon 66, nylon 11, nylon 12, and copolyamides and mixed polyamides of these.

The relative viscosity of the polyamide in the present invention is not particularly limited, but 96% concentrated sulfuric acid is used as a solvent and
Relative viscosity of 1.5 to 5.0 determined at 25 ℃ and a concentration of 1g / 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 used in the present invention is obtained by heat-treating a mixture of talc and sodium and / or lithium silicofluoride or fluoride. As a specific method, there is a method disclosed in Japanese Patent Laid-Open No. 2-149415. That is, this method uses talc as a starting material, and intercalates sodium ions and / or lithium ions into the starting material to obtain a swellable fluoromica-based mineral. In this method, talc is mixed with silicofluoride and / or fluoride, and is mixed in a magnetic crucible for about 700 to 1200.
Fluorine mica-based mineral can be obtained by a short-time heat treatment at ℃. The swellable fluoromica-based mineral used in the present invention is particularly preferably one produced by this method.

To obtain a swellable fluoromica-based mineral,
The metal constituting the silicofluoride or fluoride must be sodium or lithium among the alkali metals. 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. Further, the amount of silicofluoride and / or fluoride mixed with talc is preferably in the range of 10 to 35% by weight of the total mixture, and if the amount is out of this range, the yield of swelling fluoromica-based minerals is reduced.

The swellable fluoromica-based mineral produced by the above method has a structure represented by the following general formula. α (MF) · β (aMgF ₂ · bMgO) · γSiO ₂ (In the formula, 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. )

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 and water molecules or cations between the layers to increase the interlayer distance, or further swelling and cleavage. The characteristic is that the particles become ultrafine particles. The fluoromica-based mineral represented by the formula exhibits such swelling property.

The swellable fluoromica-based mineral used in the present invention has a layer thickness in the c-axis direction of 9 to 20Å as measured by the X-ray powder method.
belongs to.

In the step of producing the swellable fluoromica-based mineral used in the present invention, it is also possible to mix a small amount of alumina (Al ₂ O ₃ ) to adjust the swellability of the swellable fluoromica-based mineral produced. is there.

The amount of the swelling fluoromica-based mineral compounded is 0.01 to 100 parts by weight of the monomer to form 100 parts by weight of the polyamide.
The amount is 100 parts by weight, preferably 0.1 to 20 parts by weight.
If the amount is less than 0.01 part by weight, the effect of improving mechanical strength, heat resistance and dimensional stability cannot be obtained, and if it exceeds 100 parts by weight, the toughness is greatly reduced.

In the present invention, the amount of water added is preferably small in order to suppress the incorporation into the swelling fluoromica-based mineral and to reduce foaming during polymerization, but usually 100 parts by weight of polyamide is formed. The amount is 0.1 to 9 parts by weight based on the amount of the monomer used. The amount added is 0.1
If it is less than 9 parts by weight, the degree of polymerization of the polymer cannot be increased to a level at which it can be molded, and if it exceeds 9 parts by weight, foaming tends to occur during polymerization, and a resin composition containing bubbles tends to be easily obtained.

The molecular weight regulator used in the present invention is a compound capable of reacting with an amino group and / or a carboxyl group, and specifically, formic acid, acetic acid, propionic acid,
Butyric acid, valeric acid, pivalic acid, caproic acid, enanthic acid,
Caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, benzoic acid, methylbenzoic acid, butylbenzoic acid, diethylamine, propyl Examples thereof include amine, butylamine, hexylamine, diisopropylamine, ethylenediamine, hexamethylenediamine, aniline, methylaniline and butylaniline.

The addition amount of the molecular weight modifier is 100
It is in the range of 0.001 to 10 parts by weight with respect to the amount of the monomers forming the parts by weight. If the amount added is less than 0.001 part by weight, the effect of controlling the molecular weight will be small and foaming will tend to occur during polymerization. Conversely, if it exceeds 10 parts by weight, the polymerization time will be lengthened in order to raise the degree of polymerization of the polymer to a level at which it can be molded. It is necessary and disadvantageous in terms of productivity.

In the present invention, if necessary, glass fiber, carbonized fiber, aramid fiber, calcium carbonate, talc, mica, potassium titanate, boron nitride, inorganic silicate, silica gel, hydrotalcite, cristobalite, clay, etc. Such reinforcing fillers, heat stabilizers, light stabilizers, antioxidants, plasticizers, lubricants, colorants, flame retardants, and other additives can be used in combination.

The resin composition obtained by the method of the present invention is made into pellets, powders or other shapes by using a usual melt-kneading processing apparatus such as an extruder, a Banbury mixer, a kneader, and then injection molding and extrusion. Various types of molded articles can be processed by generally known plastic molding methods such as molding, blow molding, vacuum molding, and press molding, but injection molding is particularly preferably used.

[0031]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, the raw materials and the measuring methods used in the evaluation of the examples and comparative examples are as follows. (1) Raw material 1. Swelling Fluorine Mica-Based Minerals Talc crushed to an average particle size of 2 μm with talc was mixed with the silica fluoride shown in Table 1 having an average particle size of 2 μm to 20% by weight of the total amount. Put this in a magnetic crucible and hold it at 800 ° C for 1 hour in an electric furnace.
-1 and M-2 fluoromica minerals were synthesized. As a result of measuring the generated fluoric mica-based mineral by the X-ray powder method, the peak corresponding to the thickness 9.2Å of the raw material talc in the c-axis direction disappeared,
A peak corresponding to 12 to 16 ° indicating the formation of swellable fluoromica-based mineral was observed.

[0032]

[Table 1]

(2) Measuring method 1. Tensile strength, tensile modulus and breaking elongation were measured based on ASTM D-638. 2. Flexural strength and flexural modulus Measured according to ASTM D-790. 3. Izod impact strength Measured according to ASTM D-256. 4. Heat distortion temperature Measured according to ASTM D-648. 5. Bulk specific gravity diameter 2.0mm, length 2.0mm to make a cylindrical pellet,
Measured based on JIS-K6722.

Example 1 For 10 kg of ε-caprolactam, 300 g of water and 400 g of M
-1, and 10 g of benzoic acid as a molecular weight modifier were mixed in a reactor having an internal volume of 30 liters and ε-caprolactam was polymerized to obtain a reinforced nylon 6 resin composition. The polymerization reaction was performed as follows. That is, a raw material mixture was heated to 250 ° C. with stirring, while gradually releasing water vapor, boosted from 4 kg / cm ² to a pressure of 15 kg / cm ^2, then, after pressure release to atmospheric pressure, 3 at 260 ° C. Polymerized for hours. When the polymerization was completed, the reinforced nylon 6 resin composition was discharged from the reactor and cut into pellets. The pellets of the obtained reinforced nylon 6 resin composition were treated with hot water at 95 ° C. for scouring and then vacuum dried. The pellet had almost no bubbles entrapped in its appearance and had a good bulk specific gravity of 0.70. Cylinder temperature of these pellets was measured using a twin-screw extruder (Ikegai Tekko Co., Ltd., PCM-45 type).
Injection molding was carried out at 250 ° C., mold temperature 70 ° C., injection time 6 seconds, cooling time 6 seconds to prepare a test piece having a thickness of 1/8 inch, and a physical property test was conducted. Table 2 shows the obtained results.

Examples 2 to 5 Pellets were obtained by polymerizing in the same manner as in Example 1 except that acetic acid, adipic acid, aniline or hexamethylenediamine (HMDA) was used instead of benzoic acid. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 2 shows the obtained results.

[0036]

[Table 2]

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 without adding benzoic acid to obtain pellets. The pellet had air bubbles entrapped on the surface remarkably and had a bulk specific gravity of 0.48, which was very small, and floated in water. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 3 shows the obtained results.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that the compounding amount of benzoic acid was changed to 2.0 kg, but the polymerization degree of the polymer could not be increased until pellets could be prepared.

Comparative Example 3 Pellets were obtained by polymerizing in the same manner as in Example 1 except that M-1 was not blended. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1, and a physical property test was conducted. As a result, mechanical strength and heat resistance were poor. Table 3 shows the obtained results.

Comparative Example 4 Polymerization was carried out in the same manner as in Example 1 except that the amount of water was changed to 1.5 kg to obtain pellets. The pellet had air bubbles entrapped on the surface remarkably and had a bulk specific gravity of 0.45, which was very small, and was floating in water. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 3 shows the obtained results.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 1 except that the amount of water was changed to 5.0 g, but the polymerization degree of the polymer could not be increased until pellets could be prepared.

[0042]

[Table 3]

Example 6 Polymerization was carried out in the same manner as in Example 1 except that M-2 was used in place of M-1, to obtain pellets. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 4 shows the obtained results.

Example 7 Polymerization was carried out in the same manner as in Example 1 except that M-2 was used instead of M-1 and acetic acid was used instead of benzoic acid to obtain pellets. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 4 shows the obtained results.

Example 8 Polymerization was carried out in the same manner as in Example 1 except that M-2 was used instead of M-1 and adipic acid was used instead of benzoic acid to obtain pellets. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 4 shows the obtained results.

Example 9 Polymerization was carried out in the same manner as in Example 1 except that M-2 was used instead of M-1 and aniline was used instead of benzoic acid to obtain pellets. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 4 shows the obtained results.

Example 10 Polymerization was carried out in the same manner as in Example 1 except that M-2 was used instead of M-1 and HMDA was used instead of benzoic acid to obtain pellets. Using this pellet, a test piece having a thickness of 1/8 inch was prepared in the same manner as in Example 1 and a physical property test was conducted. Table 4 shows the obtained results.

[0048]

[Table 4]

[0049]

EFFECTS OF THE INVENTION According to the present invention, in a method for producing a reinforced polyamide resin composition by adding a swelling fluoromica-based mineral to a monomer forming a polyamide and polymerizing the same, the occurrence of bubbles is reduced and the mechanical strength is reduced. It is possible to obtain a reinforced polyamide resin composition excellent in toughness, heat resistance and dimensional stability.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichiro Katahira, 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Central Research Institute (72) Inventor Izumi Yoshida, 23 Uji Kozakura, Uji City, Kyoto Unitika Stock Company Central Research In-house

Claims (1)

[Claims] 1. A swellable fluoromica mineral 0.01 to 100 parts by weight, water 0.1 to 9 parts by weight, and a carboxyl group and / or an amino group as a molecular weight regulator, relative to the amount of a monomer forming 100 parts by weight of polyamide. Compound that can react 0.001
A method for producing a reinforced polyamide resin composition, which comprises polymerizing a monomer in the presence of about 10 parts by weight.