JPH0619013B2 - Reinforced polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has excellent vibration damping performance in a wide temperature range from low temperature to high temperature, and is excellent in mechanical properties such as bending elastic modulus and bending strength and heat resistance. The present invention relates to a reinforced polyamide resin composition.

In general, plastic materials are lighter in weight than metal materials, and therefore, in recent years, research has been conducted on converting various metal parts for automobiles into plastic products, and their practical application is progressing. Of the plastic products, polyamide resin products have excellent toughness, heat resistance, oil resistance, etc., so that their application is being advanced to parts used at high temperatures such as cylinder head covers and oil pans. On the other hand, recently, from the viewpoint of automobile noise regulation, it is expected that these plastic parts will have improved vibration damping and sound insulation properties in addition to weight reduction.However, for polyamide resin products, cylinder head covers, 10 like an oil pan
Under high temperature conditions near 0 ° C, the damping performance based on the viscoelastic properties of the plastic material is significantly reduced, so that there is a problem that the damping performance cannot be expected substantially. this is,
Generally, plastic materials have strong viscoelastic properties and are expected to have damping performance, but on the other hand, they have a large temperature dependence and the damping performance is mainly due to the loss tangent of the mechanical dispersion based on the glass transition of the plastic material. (Hereinafter tanδ
Called. It is highest around the maximum temperature (see the note in Table 1 below), and generally at a temperature in a practical range other than that, it is due to a marked decrease in vibration damping performance. For example, ordinary polyamide resins such as nylon 12, nylon 6 and nylon 66 have a tan based on this glass transition.
The maximum of δ usually appears around 50 ° C, and at high temperature tanδ
The value of becomes significantly smaller. Furthermore, in order to improve the mechanical properties of these polyamide resins, glass fiber, mica,
When inorganic reinforcing agents such as talc, wollastonite, calcium carbonate, and alumina are used alone or in combination, the tan δ curve becomes broader than that of the case without addition, and the maximum value of tan δ decreases accordingly. . This decrease is the main reason why large vibration damping performance cannot be expected under high temperature use conditions.

As a method of improving such properties, it is considered to shift the glass transition temperature of the polyamide resin to a high temperature side, and for example, a copolymer with a monomer having small molecular mobility such as an aromatic monomer is used. However, due to problems such as a decrease in crystallinity and a decrease in vibration damping performance on the low temperature side, the effect could not be expected. Also,
From the viewpoint of retaining vibration damping properties under a wide temperature range condition, the most promising method is the modification of the polymer such as polymer blend or graft by multi-component multi-phase formation.
Polymers that can be blended with polyamide resins without significant reduction in strength are limited, and nitrile rubber, acid-modified EPDM, ionomers, etc. are known so far, but the glass transition temperature of these polymers is limited. Is 0 ° C or less, no improvement effect is seen on the high temperature side, and in addition, the heat resistance of the nitrile gome is decreased and acid modification is not performed.
EPDM and ionomer have the drawbacks of reduced heat resistance and oil resistance, and the grafting method is limited in the polymers that can be grafted, and there are problems such as cost up. Nakatsuta.

The present inventors obtain a reinforced polyamide resin composition having excellent vibration damping performance in a wide temperature range from low temperature to high temperature, and having excellent mechanical properties such as bending elastic modulus and bending strength and heat resistance. Therefore, as a result of various studies, it was composed of (A) polyamide resin (A), (B) tackifier resin (a) 20 to 80% by weight, and thermoplastic elastomer (b) 80 to 20% by weight.
A composition obtained by mixing the compositions (B) and (C) mica (C) having a loss tangent (tan δ) of 0.1 or more in a temperature range of 20 ° C. in the proportions described in the following 1) and 2) is It was found that the physical properties of can be satisfied.

1) The amount of the polyamide resin (A) used and the amount of the composition (B) used are 90:10 to 50:50 by weight, and 2) the polyamide resin (A) and the composition (B). And the total amount of mica (C) used are 95: 5 by weight.
The present invention is described in detail below.

The tackifier resin (a) used in the composition of the present invention is generally a natural rubber, a synthetic rubber, a natural-synthetic compounded rubber, a rubber-based adhesive, a latex, etc. Materials that are blended for the purpose of increasing tackiness, that is, so-called resin materials having properties that can be used as tackifiers (Tackifiers), which can be usually used as tackifiers Any of the resinous substances described above can be used. Examples of such a resin material include coumarone / indene resin, coumarone resin mixture (coumarone resin, naphthenic oil, phenol resin, rosin, etc.), such as coumarone resin tackifier resin material; P-No. 3 butylphenol / acetylene resin, phenol / formaldehyde resin, terpene / phenol resin, polyterpene resin, xylene / formaldehyde resin and other tackifier resin materials made of phenol / terpene resin; synthetic polyterpene resin, aromatic hydrocarbon resin , Aliphatic hydrocarbon resin, Aliphatic cyclic hydrocarbon resin, Unsaturated hydrocarbon polymer, Isoprene resin, Hydrogenated hydrocarbon resin, Hydrocarbon tackifying resin, Polymerization special polyester, Polybutene, Atactic polypropylene , Liquid polybutadiene, low molecular weight Resin materials for tackifiers consisting of petroleum hydrocarbon resins such as rubber and the like; rosin pentaerythritol ester, glycerol ester, hydrogenated rosin, highly hydrogenated utudrosine, hydrogenated rosin methyl ester, triethylene glycol Ester, pentaerythritol ester, other ester,
Resin materials for tackifiers composed of high-melting point ester resins, polymerized rosins, glycerol esters of polymerized rosins, zinc resinates, cured rosins, and other rosin derivative systems; other resin acids and amine-resin soap mixtures, synthetic resins and phthalates Examples include various types of resin materials used for tackifier applications, such as acid ester co-condensation products.

The thermoplastic elastomer (b) used in the composition of the present invention is a polymer material that exhibits rubber elasticity at room temperature, is plasticized at high temperature, and can be processed by a usual thermoplastic resin molding machine. Examples thereof include olefin-based, styrene-based, polyamide-based, polyester-based, polyurethane-based and ethylene-based thermoplastic elastomers. (The classification of thermoplastic elastomers is, for example, Plastic Vo1.36, NO1 (1985), Japan Rubber Association magazine Vo1.57, NO11 (19
84). ) Preferred examples include (1) nylon 6, nylon 66, nylon 11, nylon 12, nylon 61
Polyamide-rubber co-polymer obtained by copolymerizing polyamide such as 0, nylon 612 and nylon 69 with polyether rubber which is polyalkylene oxide glycol such as polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol and polyhexamethylene oxide glycol. A polyester-rubber copolymer obtained by copolymerizing the above polyether rubber with a polyester such as (2) polyethylene terephthalate or polybutylene terephthalate, (3) ethylene, unsaturated carboxylic acid metal salt and unsaturated carboxylic acid or unsaturated Examples thereof include ionomers of terpolymers or quaternary copolymers composed of saturated carboxylic acid and unsaturated carboxylic acid ester.

The tackifier (a) and the thermoplastic elastomer (b) have good compatibility, and the tackifier resin (a) and the thermoplastic elastomer
It is necessary that the tan δ of the dynamic viscoelasticity of the mixture of (b) is 0.1 or more in the temperature range of 60 ° C. to 120 ° C., and the tackifier resin (a) and the thermoplastic elastomer satisfying this condition. All mixtures of (b) can be applied.

More preferably, the compatibility between the tackifier resin (a) and the soft segment of the thermoplastic elastomer (b) is good, and the hard segment of the thermoplastic elastomer (b) serves as a so-called compatibilizer of the polyamide resin (A). It is desirable that the strength can be prevented from lowering, but it is also possible to impart a functional group to the thermoplastic elastomer (b) to improve the compatibility with the polyamide resin (A).

In addition, it is desirable to select the tackifier resin (a) which has poor compatibility with the polyamide resin (A) because it does not change the crystallinity of the polyamide resin itself.

For example, when the thermoplastic elastomer (b) is a polyamide-polyether rubber copolymer, the tackifier resin (a) described above.
Among them, coumarone-indene resin, hydrogenated rosin ester resin, and terpene phenol resin are polyamide-
Good compatibility with rubber copolymers and good results can be obtained.

Polyamide resin (A) used in the composition of the present invention
As, polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 6.6), polyundecanoamide (nylon 11), polydodecaamide (nylon)
12), polyhexamethylene sebacamide (nylon 6.1
0), polyhexamethylene docanamide (nylon 6.1)
2), polyhexamethylene azelamide (nylon 6.
9), polyxylylene adipamide, polyhexamethylene terephthalamide, polyphenylene phthalamide, acid-modified EP
There are polyolefin-modified nylon modified with DM, ionomer, etc., and, of course, copolymers and mixtures thereof can also be used.

The mica (C) used in the present invention is muscovite mica [K ₂ Al ₄ (Si ₃ Al) ₂ O 20 (OH) ₄ ], phlogopite mica [K ₂ Mg ₆ ) Si ₃ Al) ₂ O 20 (OH). ) ₄ ], biotight mica [K ₂ (Mg, Fe ²⁺ ) ₆ (Si ₃ Al) ₂ O 20
(OH) ₄ ] and other various mica, which are usually added to a thermoplastic resin and used, can be applied. More preferably, mica having a particle size of 200 mesh or more or a weight average particle size of 80 μm or less, the surface of which is treated with a silane coupling agent or the like is preferable.

The composition of the present invention is prepared using the above-mentioned four main raw materials, and comprises (A) a polyamide resin (A), (B) a tackifier resin (a) 20 to 80% by weight and a heat 80 to 20% by weight of the plastic elastomer (b), 60 to 1
A composition comprising a composition (B) having a loss tangent (tan δ) of 0.1 or more in a temperature range of 20 ° C. and (C) mica (C), wherein the amount of the polyamide resin (A) used and the composition (B) are ) Is used in a weight ratio of 90:10 to 50:50, and the total amount of the polyamide resin (A) and the composition (B) and the amount of the mica (C) used are , 95: 5 by weight
It is characterized by being 50:50.

In the composition (B), if the tackifier resin (a) is less than 20% by weight, it is difficult to maintain the tan δ of the composition (B) at a high value in a wide temperature range, and accordingly the polyamide resin
The improvement in damping property against (A) is small.

80% by weight of the tackifier resin (a) in the composition (B)
When it exceeds, it becomes difficult to knead with the polyamide resin (A),
Also, the strength is significantly reduced.

The composition ratio of the tackifier resin (a) and the thermoplastic elastomer (b) is within the above numerical range, the tackifier resin (a)
Types, properties (softening temperature, etc.) and thermoplastic elastomers
It can be appropriately determined according to the type and property of (b).

In general, it is a well-known fact that the addition of mica (C) to polyamide resin (A) improves mechanical properties and heat resistance, but on the other hand, the maximum value of tan δ also decreases and the vibration damping performance decreases on average. It is also well known to do. However, when the composition (B) and mica (C) are added to the polyamide resin (A) in the mixing ratio as described above, the vibration damping performance is excellent in a wide temperature range, and the bending elastic modulus, the mechanical properties such as bending strength, etc. It was also confirmed that the heat resistance was remarkably improved. Even when only the composition (B) is added to the polyamide resin (A), the vibration performance is improved, but the properties such as rigidity, strength and heat resistance are unsuitable. Therefore, in order to achieve the object of the present invention completely, the combined use of mica (C) in addition to the composition (B) is indispensable.

The composition ratio of the composition (B) is 9 with respect to the polyamide resin (A).
If the amount is less than 0:10, the effect of improving the damping property against the polyamide resin (A) is small, and if it exceeds 50:50, the polyamide resin (A) loses its original properties such as toughness and heat resistance. Is not preferable. Further, when the mica (C) is less than 5% by weight of the total composition, a sufficient reinforcing effect cannot be obtained, and when it exceeds 50% by weight, moldability is deteriorated.

The composition ratio of the polyamide resin (A) and the composition (B) and mica (C) is determined according to the type and property of each compounding component and the required quality, but the mica in the reinforced polyamide resin composition of the present invention ( A part of C) may be replaced with an inorganic reinforcing material such as glass fiber, wollastonite, talc, calcium carbonate or the like for the purpose of improving strength, impact resistance, abrasion resistance and the like. Further, known auxiliary agents such as heat and light stabilizers, dyes and pigments, flame retardants, and plasticizers may be added and used.

The method itself for producing the novel reinforced polyamide resin composition according to the present invention may be a known method as a method for producing this type of resin composition, for example, a pellet-like or powder-like tackifier. The resin and the thermoplastic elastomer are mixed with a blender, and a composition (B) is produced through an extruder, and then the polyamide resin (A), the composition (B), and mica (C) are mixed with a blender and passed through the extruder. A two-stage method of kneading can be mentioned. Tackifier resin
(a), thermoplastic elastomer (b), polyamide resin (A),
A one-stage system in which mica (C) is mixed with a blender and kneaded with an extruder is also applicable. In addition, (a), (b),
A mixture of the four components (A) and (C) may be directly put into a hopper of an injection molding machine to obtain a molded product simultaneously with melt mixing. Composition
When producing (B), the workability in handling can be improved by adding a small amount of a thickening filler such as silica or a crosslinking agent for polyamide such as a phenol resin or an epoxy resin to increase the viscosity.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

The samples of Comparative Examples 2 to 6 and Examples 1 to 10 are shown in Tables 1 to 3 respectively.
All the components used were mixed in a blender in the blending ratio of each component shown in, and the mixture was prepared by kneading with a vent type twin-screw kneading extruder (screen diameter 30 mm). The test pieces of the samples of Comparative Examples 1 to 6 and Examples 1 to 10 were molded by injection molding except for the measurement sample of loss tangent (tan δ). Tensile strength is measured by ASTM test method D63
8. Flexural modulus and flexural strength are measured by ASTM test method D79
0, the heat distortion temperature was measured by the method described in ASTM Test Method D648. Also, the loss tangent (tan
The measurement of δ) was carried out by punching from a 0.5 mm sheet prepared by press molding. When kneading, molding and measuring physical properties, the sample was sufficiently dried before use.

In contrast to Comparative Example 1 of the polyamide resin (A) alone, Comparative Example 2 in which only the mica (C) is mixed with the polyamide resin (A) shows an improvement in mechanical properties and heat resistance, but a vibration damping performance. No improvement is recognized. Comparative Examples 3, 4 and 5 are the components (a), (b), (A), used in the composition of the present invention described in the text.
Although three of the four of (C) are used, none of them results in satisfying the object of the present invention. That is, in the case of Comparative Example 3 in which the polyamide resin (A) was mixed with the thermoplastic elastomer (b) and the mica (C), sufficient vibration damping performance was not obtained, and the polyamide resin (A) had a tackifier resin (a). ) And mica (C) are mixed, the kneading is impossible. Further, in the case of Comparative Example 5 in which the composition (B) comprising the tackifier resin (a) and the thermoplastic elastomer (b) is mixed with the polyamide resin (A), a significant improvement in vibration damping performance is recognized, Insufficient mechanical properties and heat resistance. Comparative Example 6 is an example in which 30% by weight of glass fiber is mixed with that of Comparative Example 5, and is excellent in mechanical properties and heat resistance, but the vibration damping performance is not sufficient.

On the other hand, in the case of Example 1, which corresponds to the case of mixing 30% by weight of mica (C) with that of Comparative Example 5, vibration damping performance comparable to that of Comparative Example 5 was obtained, and mechanical properties and heat resistance were obtained. The object of the present invention is completely achieved. In Examples 2 and 3, the mica (C) was mixed with a varying amount of abacus, and in Example 4, mica (C) having a different particle size was used. Excellent mechanical properties and heat resistance.

From these results, the presence of the four components of the polyamide resin (A), the tackifier resin (a), the thermoplastic elastomer (b), and the mica (C) is essential for the reinforced polyamide resin composition according to the present invention. I understand.

In the case of Example 5, a part of the mica (C) was replaced with glass fiber, but the vibration damping performance was almost the same as that of Example 1, and more excellent strength and heat resistance were obtained. To be Thus, a part of the mica (C) can be replaced with a known inorganic reinforcing agent such as glass fiber according to the purpose.

Examples 6 to 10 show examples of various polyamide resins (A) and various compositions (B) (B-1 to B-5), all of which are damping performance and mechanical properties. Both are excellent.

The composition (B) (B-1 to B-
5) tan δ is a value measured from a sheet obtained by kneading the tackifier resin (a) and the thermoplastic elastomer (b) with a Brabender and press-molding.

The reinforced polyamide resin composition according to the present invention has excellent vibration damping performance in a wide temperature range from low temperature to high temperature, and since it has excellent mechanical properties and heat resistance, high temperature in the engine room of an automobile, The present invention can be applied to a wide range of products such as a cylinder head cover, a timing belt cover, a timing gear cover, an oil pan, etc., where vibration is applied.

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Claims (7)

[Claims] 1. A polyamide resin (A) (A), (B) a tackifier resin (a) 20 to 80% by weight, and a thermoplastic elastomer (b) 80 to 20% by weight.
A composition comprising a composition (B) having a loss tangent (tan δ) of 0.1 or more in a temperature range of 20 ° C. and (C) mica (C), wherein the amount of the polyamide resin (A) used and the composition (B) are ) Is used in a weight ratio of 90:10 to 50:50, and the total amount of the polyamide resin (A) and the composition (B) and the amount of the mica (C) used are , 95: 5 by weight
A reinforced polyamide resin composition characterized by being 50:50. 2. The reinforced polyamide resin composition according to claim 1, wherein the tackifier resin (a) is a coumarone-indene resin. 3. The reinforced polyamide resin composition according to claim 1, wherein the tackifier resin (a) is a terpene-phenol resin. 4. The reinforced polyamide resin composition according to claim 1, wherein the tackifier resin (a) is a hydrogenated rosin ester resin. 5. The reinforced polyamide resin composition according to claim 1, wherein the thermoplastic elastomer (b) is a polyamide-rubber copolymer. 6. The reinforced polyamide resin composition according to claim 1, wherein the thermoplastic elastomer (b) is a polyester-rubber copolymer. 7. A terpolymer comprising ethylene, an unsaturated carboxylic acid metal salt and an unsaturated carboxylic acid as the thermoplastic elastomer (b), or ethylene, an unsaturated carboxylic acid metal salt, an unsaturated carboxylic acid and an unsaturated carboxylic acid. The reinforced polyamide resin composition according to claim 1, which is an ionomer of a quaternary copolymer comprising a carboxylic acid ester.