JPH0645749B2 - Polyamide composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improved polyamide composition, and more particularly, to a polyamide composition having a good balance of rigidity and impact resistance, particularly impact resistance at low temperature. Regarding things.

[Conventional technology]

Polyamide has well-balanced physical properties and is widely used, but its toughness is not sufficient.
Conventionally, various methods have been proposed for improving the toughness of polyamides. For example, JP-A-55-9661 discloses a method of melt-mixing a graft-modified ethylene / α-olefin copolymer with polyamide to improve flexibility. Disclosed is a method for obtaining the above polyamide composition.

In addition, the applicant of the present invention is disclosed in Japanese Patent Laid-Open Nos. 59-131642 and 5
Japanese Patent Publication No. 9-78256 discloses a method of blending a polyamide with a graft-modified low-crystalline ethylene copolymer and a graft-modified or non-modified high-crystalline ethylene polymer.
Further, Japanese Patent Application No. 60-149925 discloses a method of blending a polyamide with a graft-modified low-crystalline ethylene copolymer and a low-molecular weight graft-modified ethylene copolymer.

[Problems to be solved by the invention]

The method described in JP-A-55-9661 improves the flexibility of polyamide, but the impact strength at low temperature is still insufficient, and thus JP-A-59-131642 and JP-A-59-78256. The described method is still insufficient in impact resistance depending on the application, and although the method of Japanese Patent Application No. 60-149925 has achieved the intended purpose for the time being, further improvement in rigidity is desired.

It is an object of the present invention to provide a polyamide composition having balanced rigidity and impact resistance, especially impact resistance at low temperature, without impairing the excellent physical properties of polyamide.

[Means for Solving Problems] and [Action] The present invention provides a so-called low-density graft-modified ethylene modified with component (a): polyamide and component (b): α, β-unsaturated carboxylic acid or an acid derivative thereof. -Α-olefin random copolymer, (c) component: low molecular weight modified ethylene random copolymer obtained by graft-polymerizing α, β-unsaturated carboxylic acid or its acid derivative on a low molecular weight ethylene copolymer And (d) component: a high-density ethylene-based polymer are mixed, or in addition to the above (a) component, (b) component, (c) component, (d) component, α , A β-unsaturated carboxylic acid or a derivative of a graft-modified high-density ethylene polymer modified with an acid derivative thereof is mixed.

Hereinafter, the present invention will be described in detail.

Component (a) in the present invention, polyamide is hexamethylenediamine, decamethylenediamine, dodemethylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4 -Bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m
-Or p-xylylenediamine or other aliphatic, alicyclic,
Polyamide obtained by polycondensation of diamine such as aromatic with adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid or the like, alicyclic, dicarboxylic acid such as aromatic, ε- Polyamides obtained by condensation of aminocarboxylic acids such as aminocaproic acid and 11-aminoundecanoic acid, polyamides obtained from lactams such as ε-caprolactam and ω-laurolactam, copolyamides composed of these components, or mixtures of these polyamides. Etc. are illustrated. Specifically, nylon 6, nylon 66, nylon 61
0, nylon 9, nylon 11, nylon 12, nylon 6/6
6, nylon 66/610, nylon 6/11 and the like. Of these, nylon 6 and nylon 66 are preferable in terms of good rigidity and heat resistance.

The amount of the component (a) and the polyamide in the polyamide composition of the present invention is usually 98 to 55 parts by weight, preferably 95 to 65 parts by weight.

Component (b) in the present invention, graft-modified ethylene / α-
The olefin random copolymer means that the graft amount of α, β-unsaturated carboxylic acid or its acid derivative is 0.01 to 10
% By weight, preferably 0.1 to 5% by weight, and a melt flow rate (MFR ₂ : ASTM D 1238, E) of 0.1 to 50 g / 10.
min, preferably 0.2 to 20 g / 10 min, density 0.850 to 0.900 g / cm ³ , preferably 0.855 to 0.895 g / cm
³ , ethylene content of 30 to 95 mol%, preferably 40
To 92 mol% and the crystallinity by X-ray is 40% or less, preferably 30% or less, and a part or the whole thereof is a graft-modified ethylene / α-olefin random copolymer.

When the graft amount of the unsaturated carboxylic acid component is less than 0.01% by weight, the compatibility with the component (a): polyamide is poor, while when it exceeds 10% by weight, some cross-linking occurs and the moldability of the composition is deteriorated. .

If the MFR is less than 0.1 g / 10 min, the melt viscosity will be too high and the moldability will be poor, while if it exceeds 50 g / 10 min, the melt viscosity will be too low and the moldability will be poor, and the mechanical strength will also be deteriorated. If the density exceeds 0.900 g / cm ³ , the impact resistance improving effect is poor, and if the crystallinity by X-ray exceeds 40%, the impact resistance improving effect is also poor.

The α-olefin constituting the modified random copolymer of the present invention is usually an α-olefin having 3 to 20 carbon atoms, specifically, for example, propylene, 1-butene, 1-hexene, 4
-Methyl-1-pentene, 1-octene, 1-decene,
1-tetradecene, 1-octadecene, etc., each consisting of a single compound or a mixture of two or more compounds.

The α, β-unsaturated carboxylic acid or its acid derivative grafted to the modified random copolymer has the same category as the α, β-unsaturated carboxylic acid component constituting the components (c) and (d) described below. It is a thing. Among them, maleic acid, bicyclo [2,2,1] hept-2-ene-5,6 dicarboxylic acid or their anhydrides are preferable.

The ethylene / α-olefin random copolymer used as the base of the modified random copolymer of the component (b) used in the present invention is
Usually, to a MFR of 0.1 to 50 g / 10min, to a density no 0.850 0.900 g / cm ^3, the ethylene content of 30 to 95 mol%
And ethylene with a crystallinity of 40% or less by X-ray and α-
It is a random copolymer with an olefin.

In order to graft-copolymerize a graft monomer selected from an α, β-unsaturated carboxylic acid or an acid derivative thereof with the random copolymer to produce a modified product, various conventionally known methods can be adopted. For example, there is a method of melting a random copolymer and adding a graft monomer to carry out random copolymerization, or a method of dissolving it in a solvent and adding a graft monomer to carry out graft copolymerization. In any case, it is preferable to carry out the reaction in the presence of a radical initiator in order to efficiently graft-copolymerize the graft monomer. The grafting reaction is usually performed at a temperature of 60 to 350 ° C. The proportion of the radical initiator used is usually in the range of 0.001 to 1 part by weight per 100 parts by weight of the random copolymer.

The component (c) in the present invention is a low molecular weight ethylene-based copolymer grafted with an α, β-unsaturated carboxylic acid or an acid derivative thereof, preferably a liquid ethylene-based copolymer at room temperature. Yes, the graft polymerization ratio is high.

That is, α, β-of the low molecular weight modified ethylene copolymer
The graft polymerization ratio of the unsaturated carboxylic acid or its acid derivative is 0.1 to 25 parts by weight, preferably 3 to 15 parts by weight, more preferably 4-1 to 100 parts by weight of the ethylene polymer.
It is in the range of 3 parts by weight. If the graft polymerization ratio of the unsaturated carboxylic acid component is out of this range, the impact strength at low temperature cannot be improved sufficiently.

Examples of the α, β-unsaturated carboxylic acid or its acid derivative include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept- Unsaturated carboxylic acids such as 2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5, Unsaturated carboxylic acid anhydrides such as 6-dicarboxylic acid anhydride, methyl acrylate, methyl methacrylate, dimethyl maleate,
Of unsaturated carboxylic acids such as maleic maleate, diethyl fumarate, dimethyl itaconic acid, diethyl citraconic acid, dimethyl tetrahydrophthalic anhydride, dimethyl bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid An ester etc. can be illustrated. Among these, maleic acid, bicyclo [2,2,1] hept-2-ene-5,6
-Dicarboxylic acids or their anhydrides are preferred.

The intrinsic viscosity [η] measured in 135 ° C. decalin of the component (c) in the present invention is 0.05 to 0.55 dl / g, preferably 0.08 to
It is in the range of 0.15 dl / g. Outside of this range, the impact strength of the polyamide composition at low temperatures is not sufficiently improved. Further, the number average molecular weight of the component (c) is usually 300 to 10,000.
The range is 0, preferably 700 to 2,000. The molecular weight distribution (▲ / ▼) measured by gel permeation chromatography is usually 4 or less, preferably
The range is 1.2 to 3.

The ethylene-based polymer constituting the component (c) in the present invention is a low molecular weight ethylene-based random copolymer composed of ethylene and an α-olefin having 3 to 20 carbon atoms, and the ethylene component is 30 to 75 mol. %, Preferably 40 to 70 mol%. If it deviates from this range, the impact strength at low temperatures will not be sufficiently improved.

3 to 2 carbon atoms which are the constituents of the component (c) in the present invention
As the α-olefin component of 0, specifically, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-
Examples thereof include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. The low molecular weight modified ethylene random copolymer can be prepared by the method proposed by the applicant in Japanese Patent Application No. 59-246330.

The low molecular weight modified ethylene-based random copolymer of the present invention,
It can be produced by reacting the low molecular weight modified random ethylene copolymer with the unsaturated carboxylic acid derivative in the presence of a radical initiator. The reaction can be carried out in the presence of a solvent or in the absence of solvent. Examples of the reaction method include a method of reacting by continuously or intermittently supplying the unsaturated carboxylic acid derivative and the radical initiator to a heated low molecular weight modified ethylene random copolymer with stirring. it can.

Component (d) in the present invention, an ethylene polymer having a high density, a homopolymer of ethylene, or ethylene and other α-olefins, such as propylene, 1-butene,
A copolymer of 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-tetradecene and the like, or a copolymer with two or more thereof, in which the content of α-olefin is less than 5 mol% It is a polymer and is in the category usually called high density polyethylene.

High density ethylene polymers usually have MFR ₂ of 0.01 to 50.
g / 10min, preferably 0.2-20g / min, density 0.940g
/ Cm ³ or more, preferably 0.955 g / cm ³ or more, and a crystallinity by X-rays of 60% or more, preferably 70% or more, either ethylene alone or a random copolymer of ethylene and α-olefin.

As the component (d), the above high-density ethylene polymer may be used as it is, but a modified product obtained by graft-copolymerizing a graft monomer selected from α, β-unsaturated carboxylic acids or acid derivatives thereof is used. Preferably. In this case, the grafting amount of α, β-unsaturated carboxylic acid or its acid derivative is 0.01 to 10% by weight, preferably 0.1 to 5% by weight.
Is.

If the MFR is less than 0.01 g / 10 min, the melt viscosity will be too high and the moldability will be poor, while if it exceeds 50 g / 10 min, the melt viscosity will be too low and the moldability will be poor, and the mechanical strength will also be deteriorated. If the density is less than 0.940 g / cm ³ or the crystallinity by X-ray is less than 60%, the rigidity is not improved. Also,
The graft-polymerized α, β-unsaturated carboxylic acid or its acid derivative within the range of 0.01 to 10% by weight has increased compatibility and further improved rigidity.

As the high-density ethylene polymer, a commercially available product produced by a known method can be used. The graft polymerization of the α, β-unsaturated carboxylic acid or its acid derivative can be carried out according to the method of the component (b).

The amounts of component (b), component (c) and component (d) in the polyamide composition of the present invention are usually the total amount of component (b) + component (c) + component (d) per 100 parts by weight of the composition. 2 to 45 parts by weight, preferably 5
To 35 parts by weight, and 25 to 75% by weight of component (b), preferably 35 to 65% by weight, based on 100% by weight of the total amount of component (b) + component (c) + component (d). The component (c) is 1 to 24% by weight, preferably 2 to 20% by weight, and the component (d) is 20 to 74% by weight, preferably 3
0 to 63% by weight.

To obtain the polyamide composition of the present invention, the component (a),
The components (b), (c) and (d) are mixed within the above range.

The mixing method is, for example, a method of mixing with a Henschel mixer, a V-blender, a ribbon blender, a tumbler blender, or after mixing, a single-screw extruder, a twin-screw extruder,
A method of granulating or crushing after melt-mixing with a kneader, Banbury mixer or the like can be adopted.

The polyamide composition of the present invention includes a heat stabilizer, a weather stabilizer, an antistatic agent, a lubricant, a slip agent, a nucleating agent, an antiblocking agent, a drip agent, an antifogging agent, a pigment, a dye, a flame retardant, an organic or Various known additives such as inorganic fillers used in addition to ordinary thermoplastic resins may be blended within a range that does not impair the object of the present invention.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a polyamide composition in which impact strength, particularly impact strength at low temperature, is further improved and rigidity and other excellent physical properties are not impaired.

The composition of the present invention, as impact resistant polyamide, is molded by various known methods such as injection molding, extrusion molding, compression molding, blow molding, foam molding, pipes, pipe coating materials, automobile parts, electric appliance parts, It can be suitably used for applications such as helmets and ski boots.

Example 1 (1) Production of Low-Molecular Weight Modified Ethylene Random Copolymer A glass 2-pack reactor with a stirrer equipped with a nitrogen blow-in tube, a water-cooled condenser, a thermometer and two dropping funnels had an ethylene composition of 50%. Mol%, number average molecular weight 810, ▲ / ▼
1.40, [η] 0.04dl / g, kinematic viscosity at 100 ℃ 22.8cst
800 g of the ethylene / propylene copolymer of (1) was added, and nitrogen substitution was carried out for 2 hours to expel dissolved oxygen. After that, the temperature inside the flask was raised to 160 ° C., and 50 g of maleic anhydride, which had been charged in advance in each of the two dropping funnels (heated to 60 ° C.,
(Liquid) and 10 g of di-tert-butyl peroxide are added dropwise over 5 hours. After additional 5 hours after the completion of dropping, the reaction is carried out and then the temperature inside the flask is raised to 180 ° C, and unreacted maleic anhydride and di-tert-butyl peroxide decomposition products are removed under a reduced pressure of 0.5 mmHg. To do.

The modified ethylene / propylene copolymer of the product is [η]
It is a yellow transparent liquid with a kinematic viscosity of 33.8 cst at 0.04 dl / g, ▲ / ▼ 1.40 and 100 ° C. The graft ratio of the maleic anhydride component is 100% ethylene / propylene copolymer.
It was 5.6 parts by weight with respect to parts by weight.

(2) Production of unsaturated carboxylic acid graft product of ethylene / α-olefin random copolymer and high density ethylene polymer (b) As a raw material of component, MFR: 2.9 g / 10 min, density:
0.860 g / cm ³ , ethylene content: 81 mol% and ethylene having a crystallinity of 3% by X-ray. A propylene random copolymer was used. As the raw material of the component (d), MFR: 5.3 g /
High-density polyethylene having a density of 0.968 g / cm ³ and a crystallinity of 77% by X-ray was used for 10 minutes.

50 parts by weight of each of the above two components, 1 part by weight of maleic anhydride, and 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3 (trade name: Perhexyl 2.5B NOF Corporation)
0.06 parts by weight after mixing with a Henschel mixer,
Melt reaction was carried out at a resin temperature of 250 ° C. with a 50 mmφ extruder. The product had an MFR of 1.3 g / 10 min, a density of 0.914 g / cm ³ , and a maleic anhydride graft amount of 0.9% by weight.

(3) Preparation of Polyamide Composition 80 parts by weight of polyamide (Nylon 6, CM-10017 manufactured by Toray Industries Inc.) was used as the component (b) + (d) to obtain the ethylene obtained in (2) above.
19 parts by weight of a mixed graft of propylene random copolymer and maleic anhydride of high-density polyethylene and (c) as a component, the low-molecular-weight modified ethylene obtained in (1) above.
1 part by weight of the propylene copolymer was kneaded to obtain a polyamide composition. Then, the physical properties of the composition were measured by the following methods.

For the physical properties other than MFR (G), a test piece obtained by injection molding was used.

Melt flow rate (MFR (G): g / 10 min) ASTM D 1238: Condition R Tensile test: In accordance with ASTM D 683, test piece shape: ASTM type-IV, thickness 3.2 mm, tensile speed: 50 mm / min Tensile test was conducted under the conditions of, tensile modulus (E: Kg / cm ² ), yield stress (YS: Kg / cm ² ), tensile strength at break (TB: Kg / cm ² ) and elongation at break (EB: %).

Bending test: In accordance with ASTM D 790, a bending test is performed under the conditions of a test piece shape: 127 × 12.7 × 3.2 mm, a bending speed: 5 mm / min, and a bending elastic modulus (FM: Kg / cm ² ) and a bending stress. (FS: Kg / cm ² ) was determined.

Izod impact strength (Kg / cm / cm): ASTM D 25
It carried out according to 6. Test piece shape: thickness 12.7 mm, notched.

The test results are shown in Table 1.

[Example 2] The same procedure as in Example 1 was carried out except that the components (b) + (d) and (c) in Example 1 were blended in the proportions shown in Table 1. The physical properties are also shown in Table 1.

Example 3 The graft ratio of the maleic anhydride component was the same as in Example 1 except that the amount of maleic anhydride used was 120 g.
12.5 per 100 parts by weight of ethylene-propylene copolymer
By weight, [η] 0.06 dl / g of the component (c) copolymer was obtained.

This copolymer was treated in the same manner as in Example 1 with polyamide and
It was blended with the components (b) + (d). The physical properties are also shown in Table 1.

[Example 4] The same procedure as in Example 3 was carried out except that the components (c) and (b) + (d) in Example 3 were blended in the proportions shown in Table 1. The physical properties are also shown in Table 1.

[Comparative Example 1] As the polyamide and the component (b) + (d) used in Example 1,
(2) obtained ethylene-propylene random copolymer and high-density polyethylene maleic anhydride graft product
A polyamide composition was obtained by compounding and kneading at a ratio of 80:20.
The same test as in Example 1 was conducted on this composition, and the results are also shown in Table 1.

Example 5 100 parts by weight of the ethylene-propylene random copolymer used in Example 1, 1 part by weight of maleic anhydride and 0.06 part by weight of perhexin 2.5B were mixed and melt-reacted. The product had an MFR of 0.8 g / 10 min and a maleic anhydride graft amount of 0.8% by weight.

9 parts by weight of the component (b), 9 parts by weight of the unmodified high-density polyethylene used in Example 1 as the component (d), and the low molecular weight modified ethylene random copolymer used in Example 3 as the component (c). The combined test was carried out with 80 parts by weight of polyamide, and the same test as in Example 1 was carried out. The results are also shown in Table 1.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area C08L 23:26) (C08L 77/00 51:06) (C08L 77/00 51:06 23:04)

Claims (2)

[Claims] 1. A component (a): polyamide and a component (b): α, β-unsaturated carboxylic acid or its acid derivative grafted amount: 0.01 to 10% by weight, melt flow rate: 0.1 to 50 g / 10 min, Density: 0.850 to 0.900
g / cm ³ , ethylene content: 30 to 95 mol%, and X-ray crystallinity: 40% or less, and a graft-modified ethylene / α-olefin random copolymer partially or wholly graft-modified, Component (c): a low molecular weight modified ethylene random copolymer obtained by graft-polymerizing an α, β-unsaturated carboxylic acid or an acid derivative thereof to a low molecular weight ethylene copolymer,
Satisfying the following conditions: (i) the ethylene-based copolymer comprises 30 to 75 mol% of ethylene and 25 to 70 mol% of α-containing 3 to 20 carbon atoms
(Ii) the graft ratio of the low molecular weight modified ethylene-based random copolymer is 100 parts by weight of the ethylene-based copolymer,
In the range of 0.1 to 25 parts by weight, (iii) 1 of the low molecular weight modified ethylene-based random copolymer
Intrinsic viscosity [η] measured in decalin at 30 ° C is in the range of 0.05 to 0.55 dl / g, and (d) component: Melt flow rate: 0.1 to 50 g / 10 mi
n, density: 0.940 g / cm ³ or more, X-ray crystallinity: 60
% Of an ethylene-based polymer, and a polyamide composition. 2. A component (a): a polyamide and a component (b): an α, β-unsaturated carboxylic acid or an acid derivative thereof grafted amount: 0.01 to 10% by weight, melt flow rate: 0.1 to 50 g / 10 min, Density 0.850 to 0.900 g
/ Cm ³ , ethylene content: 30 to 95 mol% and crystallinity by X-ray: 40% or less, and a graft-modified ethylene / α-olefin random copolymer partially or wholly graft-modified, Component c): a low molecular weight modified ethylene random copolymer obtained by graft-polymerizing an α, β-unsaturated carboxylic acid or an acid derivative thereof to a low molecular weight ethylene copolymer,
Satisfying the following conditions: (i) the ethylene-based copolymer comprises 30 to 75 mol% of ethylene and 25 to 70 mol% of α having 3 to 20 carbon atoms
-Is composed of an olefin, (ii) the graft ratio of the low molecular weight modified ethylene-based random copolymer is 100 parts by weight of the ethylene-based copolymer,
In the range of 0.1 to 25 parts by weight, (iii) 1 of the low molecular weight modified ethylene-based random copolymer
Intrinsic viscosity [η] measured in decalin at 30 ° C. is in the range of 0.05 to 0.55 dl / g, and (d) component: α, β-unsaturated carboxylic acid or its acid derivative graft amount: 0.01 to 10% by weight, melt flow rate: 0.1 to 50 g / 10 min, density: 0.940 g / cm ³ or more, crystallinity by X-ray: 60% or more, partially or wholly graft-modified ethylene-based polymer, A polyamide composition obtained by mixing and.