JPH06228436A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a soft resin composition composed of a propylene polymer, a polyamide, a specific copolymer and a plasticizer for polyamide, having high heat-resistance and exhibiting excellent impact resistance, water resistance, surface glass and paintability. CONSTITUTION:The composition is produced by compounding (A) 10-20 pts.wt. of a propylene polymer, (B) 40-60 pts.wt. of a polyamide (preferably nylon 6 or nylon 66), (C) 50-20 pts.wt. of a modified ethylene.alpha-olefin copolymer produced by grafting 0.01-5 pts.wt. of a grafting monomer selected from unsaturated carboxylic acid and its derivative (preferably maleic anhydride, etc.) to 100 pts.wt. of an ethylene.alpha-olefin copolymer having a crystallinity of 0-50% determined by X-ray and an ethylene content of 40-93mol% and (D) 2-20 pts.wt. (based on 100 pts.wt. of A+B+C) of a plasticizer for polyamide (preferably p-oxybenzoic acid ester, etc.). The component A is preferably a polymer modified by grafting with an unsaturated carboxylic acid (derivative).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition which is soft and has high heat resistance, and which is excellent in impact resistance, water resistance, surface gloss and paintability.

[0002]

BACKGROUND OF THE INVENTION Polyamide is excellent in surface gloss, heat resistance, etc., but has a problem that it is too rigid to be used as a soft material and has poor impact resistance. In order to use such a polyamide as a soft material, various attempts have been made to improve its impact resistance. As an example, conventionally, there is a method of mixing a polyamide with a rubber-like substance such as polyisobutylene, polybutadiene, an amorphous ethylene / propylene copolymer, or a modifier such as polyethylene. However, in this method, there is a limit to softening the polyamide, and these modifiers are softer than the polyamide and have a low softening point. Therefore, when the compounding amount is increased, the surface hardness of the obtained polyamide composition, There is a problem that heat resistance, oil resistance, etc. are reduced.

On the other hand, since polyolefin and polyamide have no compatibility at all, the mechanical strength such as impact resistance is extremely lowered in the mixture thereof. As a method for improving the compatibility between the polyolefin and the polyamide, various methods have hitherto been used, for example, a method in which an ionomer is added to a mixture of the polyolefin and the polyamide (Japanese Patent Publication No. Sho 43-6529).
No.), when mixing the polyolefin and the polyamide,
A method using a modified polyolefin having at least one of an acid, an ester, an amide, an acid anhydride, and an epoxide group introduced (Japanese Patent Publication No. 45-30945), or a maleic anhydride modified polypropylene when blending a crystalline polypropylene and a polyamide. Method to intervene (polymer chemistry, 29, 26
5 (1972)) and the like have been proposed.

According to these methods, the compatibility between polyolefin such as polypropylene and polyamide is improved. However, the impact resistance is not sufficiently improved, and the polyamide thus obtained cannot be used as a soft material.

In view of the above situation, the present inventor has conducted various studies in order to obtain a polyamide which is soft and has excellent impact resistance without impairing the surface gloss and heat resistance which are the characteristics of polyamide. As a result, the above problems were solved at once by adding a graft-modified product of an unsaturated carboxylic acid of a specific ethylene / α-olefin copolymer or its derivative and a plasticizer for polyamide to a composition of polypropylene and polyamide. The inventors have found that they can do so and have completed the present invention.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and is soft,
Moreover, it is an object of the present invention to provide a thermoplastic resin composition having high heat resistance and excellent impact resistance, water resistance, surface gloss, and paintability.

[0007]

SUMMARY OF THE INVENTION The thermoplastic resin composition according to the present invention comprises 10 to 20 parts by weight of a propylene polymer (A), 40 to 60 parts by weight of a polyamide (B), and a modified ethylene.
From 50 to 20 parts by weight of the α-olefin copolymer (C), and from 2 to 20 parts by weight of the plasticizer (D) for polyamide based on 100 parts by weight of the total of (A), (B) and (C). And the above-mentioned modified ethylene / α-olefin copolymer (C) has an X-ray crystallinity of 0 to 50% and an ethylene content of 40 to 93 mol%.
It is characterized in that 0.01 to 5 parts by weight of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof are graft-modified with respect to 100 parts by weight of the α-olefin copolymer.

The thermoplastic resin composition according to the present invention as described above is soft and has high heat resistance, and is excellent in impact resistance, water resistance, surface gloss and paintability.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The thermoplastic resin composition according to the present invention will be specifically described below. The thermoplastic resin composition according to the present invention includes a propylene polymer (A), a polyamide (B), the following modified ethylene / α-olefin copolymer (C), and a plasticizer for polyamide (D ) And are included.

The propylene polymer (A) used in the present invention has crystallinity (crystallinity: about 30 to 80%) and preferably has a density of 0.89 to 0.93 g / cm ³ . Melt flow rate (MFR: ASTM D 1238, L) is 0.01 to 50 g / 10 min, and a homopolymer of propylene or a small amount (for example, 10 mol% or less) of ethylene, 1-butene, and 4-methyl. -1-Pentene, 1-
It is a block or random copolymer with an α-olefin such as hexene. Further, a part or all of these polymers may be modified with a graft monomer, and preferably 0.001 or less by a graft monomer selected from unsaturated carboxylic acids or their derivatives.
It is preferred to use the graft-modified (co) polymer in an amount of from 10 to 10% by weight, preferably from 0.1 to 5% by weight. Particularly, it is preferable to use the propylene polymer graft-modified in such an amount because a composition excellent in impact resistance can be obtained. In the present invention, such propylene (co) polymers may be used alone or in combination of two or more.

As the polyamide (B) used in the present invention, hexamethylenediamine, decamethylenediamine,
Dodecamethylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m- or Aliphatic, alicyclic and aromatic diamines such as p-xylidylenediamine and adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid and other aliphatic, alicyclic and aromatic compounds Polyamide obtained by polycondensation with dicarboxylic acid, ε-aminocaproic acid, polyamide obtained by condensation of aminocarboxylic acid such as 11-aminoundecanoic acid, ε-caprolactam, polyamide obtained from lactam such as ω-laurolactam or Examples thereof include a copolyamide composed of these components and a mixture of these polyamides. Specific examples include nylon 6, nylon 66, nylon 610, nylon 9, nylon 11, nylon 12, nylon 6/66, nylon 66/610, nylon 6/11. Among these, Nylon 6 and Nylon 66, which have excellent melting point, rigidity and the like and have a large effect of modifying the propylene (co) polymer (A), are preferable. The molecular weight is not particularly limited, but usually the relative viscosity ηr (JISK6810
, Measured in 98% sulfuric acid) is 0.5 or more, preferably 2.0 or more.

The modified ethylene / α-olefin copolymer (C) used in the present invention has a crystallinity of 0 to 50 by X-ray.
%, Preferably 0 to 30%, and 100 parts by weight of an ethylene / α-olefin copolymer having an ethylene content of 40 to 93 mol%, preferably 70 to 90 mol%, an unsaturated carboxylic acid or a derivative thereof. 0.01 to 5 parts by weight, preferably 0.1 to 5 parts by weight of a graft monomer selected from
It is a copolymer graft-modified with 1.0 part by weight.

The α-olefin component unit constituting the modified ethylene / α-olefin copolymer (C) is preferably a component unit derived from an α-olefin having 3 or more carbon atoms, especially about 3 to 18 carbon atoms. When deriving such an α-olefin component unit, propylene, 1-butene,
1-hexene, 4-methyl-1-pentene, 1-decene and the like can be used, and these α-olefins are used alone or in combination of two or more. The ethylene / α-olefin copolymer is usually a copolymer of ethylene and α-olefin, but depending on the case, a trace amount, for example, 0.
It does not matter if the diene component is contained within the range of 5 mol% or less.

Examples of the unsaturated carboxylic acid or its derivative include acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid,
Isocrotonic acid, nadic acid ^TM (endocis-bicyclo
Unsaturated carboxylic acids such as [2,2,1] hept-5-ene-2,3-dicarboxylic acid) or their derivatives, such as acid halides, amides, imides, anhydrides, esters, and the like. For example, maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate and the like are used. Among these, anhydrides are preferable, and maleic anhydride and nadic acid ^TM are particularly preferably used.

The modified ethylene / α-olefin copolymer (C) used in the present invention is obtained by modifying the ethylene / α-olefin copolymer with a graft monomer. The graft ratio of this graft monomer is ethylene. -It is necessary to be in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the α-olefin copolymer, and further 0.1 to 1.
It is preferably in the range of 0 parts by weight. When the graft ratio of the graft monomer is less than 0.01 parts by weight,
There is a tendency that the compatibility between the polyamide and the modified ethylene / α-olefin copolymer is lost, the resulting composition or molded product is delaminated, and the impact resistance improving effect is reduced. Further, when the graft ratio is more than 5 parts by weight, the degree of crosslinking of the graft-modified product increases, and the impact resistance of the thermoplastic resin composition is not so improved.

Furthermore, the melt flow rate (MFR, ASTM D 123 of the modified ethylene / α-olefin copolymer (C)
8, L) is usually 0.01 to 20 g / 10 min, preferably 0.05 to 10 g / 10 min.

In order to graft-copolymerize a graft monomer selected from unsaturated carboxylic acids or derivatives thereof with an ethylene / α-olefin copolymer, various conventionally known methods can be adopted. For example, by melting an ethylene / α-olefin copolymer or dissolving it in a solvent,
There is a method of performing graft polymerization by adding a graft monomer to the obtained melt or solution. At the time of graft polymerization, other vinyl monomers such as styrene may be present together. In particular, modified ethylene / α obtained by efficient graft polymerization using a radical generator
-The olefin polymer (C) is a raw material of ethylene / α
-It is suitable for this application because it is less likely to decompose the olefin copolymer due to oxidation.

Examples of the radical generator include organic peroxides, organic peresters and azo compounds. Specific examples of the organic peroxides and organic peresters include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide and di-ter.
t-Butyl peroxide, 2,5-dimethyl-2,5-di (peroxide benzoate) hexyne-3,1,4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butyl peracetate, 2,5 -Dimethyl-2,5-di (tert-butylperoxy) hexyne-3,2,
5-Dimethyl-2,5-di (tert-butylperoxy) hexane, tert-butylperbenzoate, tert-butylperphenylacetate, tert-butylperisobutyrate, tert-butylper-sec-octoate, tert-butylper Pivalate, cumyl perpivalate and tert-
Butyl perdiethyl acetate and the like can be mentioned.

Specific examples of the azo compound include azobisisobutyronitrile and dimethylazoisobutyrate. Of these, organic peroxides are preferable, and specifically dicumyl peroxide and di-t
ert-Butyl peroxide, 2,5-dimethyl-2,5-di (tert
-Butylperoxy) hexyne-3,2,5-dimethyl-2,5-
Di (tert-butylperoxy) hexane, 1,4-bis (te
Dialkyl peroxides such as rt-butylperoxyisopropyl) benzene are preferably used.

Polyamide plasticizer (D) used in the present invention
Is limited to sulfonamides and oxybenzoic acid esters that are compatible with polyamide. As sulfonamides, N-ethyl-p-toluenesulfonamide, N-ethyl-
O, p-toluenesulfonamide and N-butylbenzenesulfonamide are preferably used. As the oxybenzoic acid ester, p-oxybenzoic acid ester is preferably used.

In the thermoplastic resin composition of the present invention, the amount of the propylene polymer (A) is 10 to 20 parts by weight, preferably 10 to 15 parts by weight, and the polyamide (B) is 40 to 6 parts by weight.
The amount of the modified ethylene / α-olefin copolymer (C) is 0 to 20 parts by weight, preferably 45 to 55 parts by weight, the modified ethylene / α-olefin copolymer (C) is 50 to 20 parts by weight, preferably 40 to 30 parts by weight. D) is a total of 1 of (A), (B) and (C)
2 to 20 parts by weight, preferably 5 to 15 parts by weight, relative to 00 parts by weight
Included in parts by weight.

If the propylene polymer (A) is less than 10 parts by weight, the water absorption tends to be large, and if it exceeds 20 parts by weight, the flexural modulus tends to be large. If the polyamide (B) is less than 40 parts by weight, the polyamide phase cannot form a matrix and the heat resistance is significantly lowered, while if it exceeds 60 parts by weight, it tends to be difficult to use as a soft material. If the amount of the modified ethylene / α-olefin copolymer (C) is less than 20 parts by weight, impact resistance and paintability are extremely low, and it tends to be difficult to use as a soft material. On the other hand, if it exceeds 50 parts by weight, the heat resistance and oil resistance of the composition tend to be lowered.

If the amount of the plasticizer (D) for polyamide is less than 2 parts by weight, the flexibility tends to be poor, while if it is more than 20 parts by weight, the heat resistance tends to decrease. To obtain the thermoplastic resin of the present invention, the propylene polymer (A), polyamide (B),
After mixing the modified ethylene / α-olefin copolymer (C) and the plasticizer for polyamide (D) in an amount within the above range,
A method of melt-kneading and granulating or crushing may be adopted. When mixing, for example, a Henschel mixer, V-
A blender, a ribbon blender, a tumbler blender, etc. are used. A single screw extruder, a twin screw extruder, a kneader, a Banbury mixer, etc. are used for the melt kneading.

The propylene polymer composition of the present invention includes a heat resistance stabilizer, weather resistance stabilizer, antistatic agent, lubricant, slip agent, nucleating agent, flame retardant, oil agent, pigment or dye, glass fiber, carbon fiber, titanium. Potassium acid fiber, wollastonite, calcium carbonate, calcium sulfate, talc, glass flake, barium sulfate, clay, kaolin, fine powder silica, mica, calcium silicate, aluminum hydroxide,
Inorganic or organic reinforcing materials and fillers such as magnesium hydroxide, aluminum oxide and magnesium oxide may be blended within a range that does not impair the object of the present invention.

[0025]

EFFECT OF THE INVENTION The thermoplastic resin composition according to the present invention comprises a polyamide as a matrix, and this polyamide is combined with a specific modified ethylene / α-olefin copolymer, a propylene polymer and a plasticizer for polyamide. Therefore, the flexibility and impact resistance are remarkably improved, and the heat resistance is maintained high. Such a thermoplastic composition of the present invention has remarkably high heat resistance as compared with styrene-based soft materials and olefin-based soft materials.

The thermoplastic resin composition of the present invention is softer than the conventionally known composition of polypropylene and polyamide, and is excellent in impact resistance even though it is extremely excellent in impact resistance. The property is also good. Therefore, it is suitably used as a soft material such as automobile parts (mainly bumpers and moldings), electric appliances, mechanical parts, industrial parts and the like, which is required to have heat resistance and impact resistance.

[0027]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

The measuring methods used in the examples of the present invention are as follows. Tensile strength: ASTM D638, 23 ° C Flexural modulus: ASTM D790, 23 ° C Surface hardness: ASTM D785 R scale Izod impact strength: ASTM D256 Notched, -30 ° C Heat distortion temperature: ASTM D648 Load 4.6 kg / cm ² Surface gloss: Judged visually in 3 stages Heat deflection: Using a test piece with a thickness of 3 mm × 25 mm width × 125 mm, make a cantilever with a span of 100 mm and measure the deflection of the free end after leaving it at 120 ° C for 1 hr. . [Production Example of Modified Ethylene / α-Olefin Copolymer] Ethylene Content 80 Mol%, Crystallinity 2%, MFR1.2
Ethylene-propylene random copolymer (EPC) 1
To 100 parts by weight of acetone 1.0 parts by weight of α, α'-bis-t
-Butylperoxy-diisopropylbenzene 0.02
A mixed solution of 1 part by weight and 1.0 part by weight of maleic anhydride was dropped and mixed in a Henschel mixer, and then granulated at 240 ° C. in a 40 mmφ extruder to obtain a crystallinity of 2% and MFR.
A maleic anhydride-grafted ethylene / propylene random copolymer (modified EPC) having a grafting amount of 0.8 and 0.80% by weight of maleic anhydride was obtained.

[0029]

Example 1 A crystallinity of 65% and a density of 0.91 g /
cm ³ , MFR of 30 g / min, grafted amount of maleic anhydride 0.3% by weight, ethylene content 23 mol%
The same block polypropylene (hereinafter referred to as modified PP)
(A) 15 parts by weight, 25 in a 1% solution in 98% sulfuric acid
Nylon 6 with relative viscosity η = 2.0 measured at
y6) (B) 50 parts by weight, modified EPC (C) 35
Parts by weight and plasticizer for polyamide: para-oxybenzoic acid ester (POBO) (D) by weight and tumbler.
After dry blending with a blender, pellets were produced by granulating at 240 ° C. with a 40 mmφ twin-screw extruder. After drying these pellets, injection molding was performed at 260 ° C. to prepare test pieces for measuring physical properties, and the physical properties were evaluated by the above-described measuring methods.

[0030]

Comparative Example 1 The procedure of Example 1 was repeated except that 1 part by weight was used instead of 10 parts by weight of POBO.

The results are shown in Table 1.

[0032]

Comparative Example 2 The same procedure as in Example 1 was carried out except that 40 parts by weight was used instead of 15 parts by weight of modified PP and 10 parts by weight was used instead of 35 parts by weight of modified EPC.

The results are shown in Table 1.

[0034]

Example 2 Example 1 was repeated except that 10 parts by weight of N-butylbenzenesulfonamide (hereinafter referred to as BMB) was used instead of 10 parts by weight of POBO.

The results are shown in Table 1.

[0036]

Comparative Example 3 The procedure of Example 1 was repeated except that PP 15 parts by weight was used instead of modified PP 15 parts by weight and BMB was used instead of POBO.

The results are shown in Table 1.

[0038]

Comparative Example 4 Example 1 was repeated except that 30 parts by weight of BMB was used instead of 10 parts by weight of POBO.

The results are shown in Table 1.

[0040]

[Example 3] Example 1 except that 10 parts by weight of the modified PP was replaced by 10 parts by weight, 50 parts by weight of NY-6 was replaced by 55 parts by weight, and 10 parts by weight of POBO was replaced by 5 parts by weight of BMB. I went the same way.

The results are shown in Table 1.

[0042]

Comparative Example 5 In Example 1, 10 parts by weight instead of 15 parts by weight of modified PP, 20 parts by weight instead of 35 parts by weight of modified EPC, 70 parts by weight instead of 50 parts by weight of NY-6, PO
Example 1 was repeated except that 5 parts by weight of BMB was used instead of 10 parts by weight of BO.

The results are shown in Table 1.

[0044]

Comparative Example 6 45 parts by weight instead of 15 parts by weight of modified PP, 15 parts by weight instead of 35 parts by weight of modified EPC, 40 parts by weight instead of 50 parts by weight of NY-6, PO
Example 1 was repeated except that 5 parts by weight of BMB was used instead of 10 parts by weight of BO.

The results are shown in Table 1.

[0046]

Comparative Example 7 The procedure of Example 1 was repeated, except that 35 parts by weight of EPC was used instead of 35 parts by weight of modified EPC.

The results are shown in Table 1.

[0048]

[Table 1]

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Claims (1)

[Claims] 1. A propylene polymer (A) of 10 to 20 parts by weight, a polyamide (B) of 40 to 60 parts by weight, an X-ray crystallinity of 0 to 50%, and an ethylene content of 40.
To 93 mol% of ethylene / α-olefin copolymer (100 parts by weight), modified ethylene / α-olefin graft-modified with 0.01 to 5 parts by weight of a graft monomer selected from unsaturated carboxylic acids or derivatives thereof. 50 to 20 parts by weight of copolymer (C), and (A) + (B) +
A thermoplastic resin composition comprising (C) = 100 parts by weight and 2 to 20 parts by weight of a plasticizer (D) for polyamide.