JP3008458B2 - Polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a polyamide resin composition having excellent flexibility, chemical resistance, oil resistance, impact resistance, and moldability, further blended with a filler, and formed by bending. The present invention relates to a polyamide composition having excellent mechanical properties such as strength, tensile strength and elongation, impact strength, and heat resistance. Since the composition of the present invention has a high strength and elongation, it provides a polyamide resin composition that can be widely used for automobile parts, various mechanical parts, and the like.

(Prior art) Conventionally, various fillers have been blended with a polyamide resin to improve mechanical properties such as bending strength, tensile strength and impact strength.

However, when rigidity and precise dimensional accuracy are required, the required performance may not be satisfied only by blending the filler with the polyamide resin.

In order to solve these problems, there is a method of blending a filler with a polyamide resin composition in which rubber, polyolefin, and the like are blended with polyamide resin. In this case, as the amount of the rubber and the polyolefin increases, the excellent properties inherent in the polyamide resin are lost.
That is, oil resistance, chemical resistance, and heat resistance decrease, and moldability deteriorates.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and its object is to provide an oil-resistant, chemical-resistant, and heat-resistant polyamide resin which is originally excellent. An object of the present invention is to provide a polyamide resin composition having excellent flexibility and moldability without deteriorating properties.

(Means for Solving the Problems) The polyamide resin composition of the present invention comprises a polyamide elastomer (A) in an amount of 5 to 95 parts by weight, a monomer selected from unsaturated carboxylic acids and unsaturated carboxylic acid derivatives, and a polyester elastomer. Is mixed with 1 to 250 parts by weight of an inorganic filler (b) based on 100 parts by weight of a polyamide resin composition (a) containing 95 to 5 parts by weight of a modified polyester elastomer (B) obtained by reacting A polyamide resin composition comprising:

The polyamide resin (A) contained in the composition of the present invention includes nylon 6, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 6 / 6,6, nylon 4,
6. Polyxylylene adipamide, polyhexamethylene terephthalamide, polyphenylene phthalamide, polyxylylene adipamide, polyxylene adipamide / hexamethylene adipamide, polyester amide elastomer, polyether amide elastomer, dimer acid Copolyamide and the like are exemplified. These can be used alone or as a mixture, or a copolymer obtained by using a monomer forming these resins is also used. The melting point of the polyamide resin is preferably 170 ° C. or higher from the viewpoint of heat resistance. Usually, polyamide resin has relative viscosity (JIS K6
(Measured in 98% sulfuric acid according to 810-1970) is preferably 1.8 or more, more preferably 2.0 or more.

Examples of the polyester elastomer used for preparing the modified polyester elastomer (B) contained in the composition of the present invention include a polyester-polyether block copolymer and a polyester-type block copolymer.

The polyester-polyether block copolymer is a block copolymer having the property of a rubber-like elastic body because polyester is a hard segment and polyether is a soft segment, and both are alternately and repeatedly arranged.

The acid and alcohol constituting such a polyester unit are mainly an aromatic dicarboxylic acid and an alkylene glycol having 2 to 15 carbon atoms, respectively. Specific examples of dicarboxylic acids include terephthalic acid, isophthalic acid, ethylenebis (p-oxybenzoic acid), naphthalenedicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, and p- (β-hydroxyethoxy). Benzoic acid and the like. Specific examples of glycols include ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-dimethyltrimethylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, cyclohexanediethanol, benzenedimethanol, and benzene. Diethanol and the like. As the above dicarboxylic acid and glycol, the melting point of a polyester having a molecular weight of a fiber forming ability,
Those that are 200 ° C or higher are suitable.

The polyether unit which is a soft segment of the block copolymer is a polyoxyalkylene glycol having an average molecular weight of about 500 to 5,000. This polyoxyalkylene glycol unit has an oxyalkylene group having an alkylene group having 2 to 9 carbon atoms as a monomer unit. Specifically, poly (oxyethylene) glycol,
Preferable examples include poly (oxypropylene) glycol and poly (oxytetramethylene) glycol. The polyether may be a homopolymer, a random copolymer, a block copolymer, or a mixture of two or more polyethers. Further, the polyether may have a small amount of an aliphatic group, an aromatic group, or the like in the molecular chain. Also,
Modified polyethers containing sulfur, nitrogen, phosphorus and the like may be used.

Polyester-polyether block copolymer,
The polyether units are contained in a proportion of 1 to 85% by weight, preferably 5 to 80% by weight, and the polyester units in a proportion of 99 to 15% by weight, preferably 95 to 20% by weight.

Examples of the polyester-type block copolymer include those obtained by reacting a crystalline aromatic polyester with a lactone. Examples of the crystalline aromatic polyester include a polymer mainly having an ester bond or an ester bond and an ether bond, having at least one aromatic group as a main repeating unit and having a hydroxyl group at a molecular terminal. . The crystalline aromatic polyester preferably has a melting point of 150 ° C. or higher when a polymer having a high degree of polymerization is formed. When used for the molding material of the polyamide resin composition of the present invention,
Polymers having a molecular weight of 5000 or more are preferred, but when used in adhesives and coating agents, polymers having a molecular weight of 5000 or less may be used. Preferred specific examples of the crystalline aromatic polyester are
It can be found in homopolyesters, polyester ethers, copolymerized polyesters, copolymerized polyester ethers and the like. Examples of the homopolyester include polyethylene terephthalate, polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6-naphthalate. Examples of polyester ethers include polyethylene oxybenzoate, poly-p-phenylene bisoxyethoxy terephthalate, and the like. Examples of the copolyester or copolyesterether include polymers mainly having a tetramethylene terephthalate unit or an ethylene terephthalate unit and further having another copolymerization component. Examples of such a copolymer component include a tetramethylene terephthalate unit, an ethylene isophthalate unit, a tetramethylene adipate unit, an ethylene adipate unit, a tetramethylene sebacate unit, an ethylene sebacate unit, a 1,4-cyclohexylene dimethylene terephthalate unit, Tetramethylene-p-
Examples thereof include an oxybenzoate unit and an ethylene-p-oxybenzoate unit. The copolymerized polyester and the copolymerized polyester ether contain 60 mol% of tetramethylene terephthalate unit or ethylene terephthalate unit.
It is preferable to include the above.

As the other lactone constituting the polyester type block copolymer, ε-caprolactone is most preferred, but enantholactone, caprylolactone and the like are also used. Two or more of these lactones may be used.

The polyester type block copolymer is obtained by copolymerizing the above-mentioned crystalline aromatic polyester and lactones in a weight ratio of 97/3 to 5/95. Preferably, the weight ratio is 95/5 to 30/70. At the time of the above copolymerization, a catalyst is added if necessary, and the mixture is heated and mixed to progress the reaction. The polyester elastomer (polyester-polyether block copolymer and / or polyester type block copolymer) thus obtained is used alone,
Alternatively, two or more kinds may be used in combination.

The modifier which is reacted with the polyester elastomer to obtain the modified polyester elastomer is selected from unsaturated carboxylic acids and derivatives thereof. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, and endo-bicyclo (2,2.1) hept- 5-ene-2,3
-Dicarboxylic acid (nadic acid), methyl-endosis-
Bicyclo (2,2,1) hept-5-ene-2,3-dicarboxylic acid (methylnadic acid) can be exemplified. Examples of the derivative of the unsaturated carboxylic acid include derivatives of the above acids such as acid halides, amides, imides, acid anhydrides and esters. Specific examples include maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate and the like. Among these, unsaturated dicarboxylic acids or unsaturated dicarboxylic anhydrides are preferably used. Particularly, maleic acid, nadic acid, or acid anhydrides thereof are preferred.

These modifiers are used in an amount of about 0.01 to about 20% by weight, preferably about 0.02 to about 20% by weight, based on the polyester elastomer.
Used in the range. If the amount is less than 0.01% by weight, the effect of improving the physical properties of the polyamide resin composition is small, and if it exceeds 20% by weight, gelation tends to occur during the graft reaction, which is not preferable.

The method of reacting (grafting and copolymerizing) the modifier with the polyester elastomer is not particularly limited, but it is desirable that an undesired component such as gel is not contained in the resulting modified polyester elastomer.
Further, when the fluidity is reduced, the processability is deteriorated, which is not desirable. Specifically, for example, a graft reaction occurs by blending the above-mentioned polyester elastomer, a modifier, and a radical generator and melt-kneading, thereby obtaining a modified polyester elastomer. As the radical generator, known organic peroxides or diazo compounds can be used. Specifically, benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-
Butyl cumyl peroxide, cumene hydroperoxide, azobisisobutyronitrile and the like can be exemplified. The amount of the radical generator used is 0.05% by weight or more, preferably 0.1 to
1.5% by weight.

In the polyamide resin composition of the present invention, the weight ratio (A) / (B) between the polyamide resin (A) and the modified polyester elastomer (B) is preferably from 95/5 to 5/95, Preferably, (A) / (B) is 90/10 to 10/90. The weight ratio of the modified polyester elastomer is
If it is smaller than 95/5, impact resistance, rigidity, etc. are not improved. When the weight ratio of the modified polyester elastomer is more than 5/95, the water resistance and the like are reduced.

The inorganic filler used in the present invention, fibrous and acicular,
Means a granular filler, such as wollastonite, talc, clay, mica, sericite, kaolin, potassium titanate, calcium carbonate, magnesium carbonate, aluminum silicate, etc., having an average particle size of 50μ or less . These may be used in combination of two or more, and may be used in combination with glass fibers. Of these fillers, wollastonite, talc, mica, clay and calcium carbonate are particularly preferred.

The inorganic filler used in the present invention needs to have an average particle size of 50 μm or less, and preferably 45 μm or less. Further, it is particularly preferably 30 μm or less. When the average particle size exceeds 50μ, not only the effect of improving mechanical strength is hardly exhibited, but also the surface property of the molded article is reduced.

If the compounding amount is less than 1 part by weight, there is no improvement effect, and if it exceeds 250 parts by weight, not only the mechanical strength is remarkably reduced, but also the molded article surface is deteriorated and the moldability and fluidity are deteriorated.

The glass filler includes chopped strands, milled fibers, glass beads and the like. In the present invention, the amount of the glass filler is preferably in the range of 1 to 250 parts by weight based on 100 parts by weight of the total of the polyamide resin and the modified polyester elastomer.

These may be used in combination of two or more, and may also be used in combination with an inorganic filler. These glass fillers may be selected depending on the purpose, such as the type and the amount of the glass filler.

In the present invention, a chopped strand bundled with a sizing agent having an average fiber length of about 1.0 to 15 mm generally used for plastic reinforcement and an average fiber length of 0.01 to 1.5 m
A glass fiber milled fiber with a small aspect ratio, which is not focused on the order of m, is preferred. If the mixing ratio is more than the above range, the dimensional stability and dimensional accuracy will decrease, and if the mixing ratio is lower than the above range, sufficient mechanical performance and physical performance will be difficult to obtain, which is not preferable. . In the present invention, as the glass beads, any of those generally used as a filler for plastics can be used, but the average particle size is 3 to 100 μm.
When the average particle size is less than 3 μm, the extrusion workability decreases, and when the average particle size is more than 100 μm, the reinforcing effect tends to decrease, which is not preferable. When the mixing ratio of the glass beads is more than the above range, the mechanical strength is lowered, and when the mixing ratio is low, the mechanical performance becomes difficult to obtain, which is not preferable.

The composition of the present invention may further contain other additives.
Additives include colorants, stabilizers, organic fillers, fibrous reinforcing agents, and various other auxiliaries. Usually, the polyamide resin (A), the modified polyester elastomer (B), and the inorganic filler are mixed under heating, and the above additives are added at any of the initial stage, the intermediate stage, and the final stage of the mixing. Can be done. For the mixing, a conventionally known device can be used. For example, a kneading device such as a reactor equipped with a stirring blade, a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll can be used alone or in combination. The temperature of the heating and mixing is preferably equal to or higher than the melting points of the polyamide resin (A) and the modified polyester elastomer (B).

(Function) The modified polyester elastomer (B) is obtained by a graft reaction of a polyester elastomer with a modifier selected from unsaturated carboxylic acids and derivatives thereof.
It is presumed that, when this and the polyamide resin (A) are mixed under heating, the carboxylic acid and its derivative subjected to the graft reaction partially react with the amino terminal group of the polyamide resin. It is presumed that this reaction promotes uniform miscible dispersion of the polyamide resin and the modified polyester elastomer. Thus, rigidity and heat resistance can be added while maintaining the excellent properties of the polyamide resin.

(Examples) The present invention will be specifically described below using examples.

In this embodiment, the polyamide resin has a relative viscosity of 2.53.
Nylon 6 (in 98% sulfuric acid; 1 g / 100 ml, 25 ° C.), nylon 6,6 having a relative viscosity of 2.51, and polymetaxylylene adipamide (MXD-6) having a relative viscosity of 2.10 were used. Vacuum-dried at 16 ° C for 16 hours before use.

As the polyester elastomer, a polyether-polyester elastomer of polytetramethylene glycol and polytetramethylene terephthalate (Perprene P150B manufactured by Toyobo Co., Ltd.) or a polyester-type block copolymer of polycaprolactone and polytetramethylene terephthalate (manufactured by Toyobo Co., Ltd.) Pelprene S-1000)
Was used. Also, as inorganic filler, Iwalastonite (NYCO A Division of Processed M
inadals Inc. NYAD325) B Talc (Hayashi Kasei Talkan PK) Ha Mika (Kuraray Szolite Mica 325-S weight average diameter 30μ) D Glass fiber chopped strand (length: 1.5 to 4.5m)
m, fiber diameter: 9 μ, and bundle width: 1 to 5 mm).

The evaluation of the characteristics of the test pieces in the examples was performed by the following test methods.

(1) Thermal deformation temperature: Thickness 1 molded at a mold temperature of 80 ° C according to ASTM D-648
A / 4 inch test piece was measured under a load of 4.6 kg / cm ² .

(2) Flexural strength: Measured according to ASTM D-790.

(3) Tensile strength and tensile elongation: Measured according to ASTM D-638.

Production Examples Modified polyester elastomers (referred to as 'and', respectively) were synthesized as follows.

100 parts by weight of the above, or 0.5 part by weight of maleic anhydride, and 0.3 part by weight of dicumyl peroxide were uniformly mixed by a mixer. This mixture was supplied to a 30 mm twin screw extruder, and a maleic anhydride modification reaction was performed at a cylinder temperature of 200 to 230 ° C. The reaction product thus obtained is
Drying with a vacuum dryer at 80 ° C. for 12 hours gave modified polyester elastomers 'and'.

Examples 1 to 8, Comparative Examples 1 to 7 After the above polyamide resin, the modified polyester elastomers 'and' obtained in the production examples and the inorganic filler were dry-blended at the ratios shown in Table 1 respectively, 30 mm
Pellets were produced using a φ twin screw extruder. The cylinder temperature at that time was 250 ° C for nylon 6,
280 ° C for nylon 6,6, 260 ° C for MXD-6
It is. The obtained pellet was vacuum dried at 70 ° C. for 16 hours.

The properties of each of the obtained compositions were measured, and the results are shown in Table 2.

As apparent from Tables 1 and 2 above, Comparative Example 1
Nos. 4 to 4 have poor compatibility between the polyamide resin and the polyester elastomer due to the use of an unmodified polyester elastomer, have a low adhesiveness between the matrix of nylon 6 and the domain of the polyester elastomer, have a reduced strength, and have a large elongation. The decline was observed. In Comparative Example 5, since the polyester elastomer was not blended, the elongation was significantly reduced as compared with the blended polyester elastomer. In addition, in the case where the inorganic filler of Comparative Example 6 was not blended, the heat distortion temperature was not so lowered and the elongation was sufficient, but it was found that the strength was inferior to those blended with them.

On the other hand, Examples 1 to 8 are polyamide resin compositions which have very well-balanced properties such as heat deformation temperature, bending rupture strength, tensile strength and elongation in order to satisfy the requirements of the present invention, and can be sufficiently satisfied. You can see that.

(Effect of the Invention) The composition of the present invention having the above-described structure has a tensile strength and elongation,
The mechanical properties such as bending rupture strength and the thermal properties such as heat deformation temperature are very well-balanced and have excellent properties.They also have good chemical resistance, oil resistance and moldability. It is excellent and can provide molded products requiring high strength elongation, heat resistance, and chemical resistance, and thus greatly contributes to the industry.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 77/00-77/12 C08L 67/00-67/08 C08K 3/00-13/08 CA (STN)

Claims (1)

(57) [Claims] 1. A modified polyester elastomer (B) obtained by reacting a polyester elastomer with 5-95 parts by weight of a polyamide resin (A) and a monomer selected from unsaturated carboxylic acids and unsaturated carboxylic acid derivatives. 95-5
A polyamide resin composition comprising 1 to 250 parts by weight of an inorganic filler (b) based on 100 parts by weight of a polyamide resin composition (a) consisting of parts by weight.