JP3008457B2 - Polyamide resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyamide resin composition having excellent flexibility, chemical resistance, oil resistance, impact resistance, and moldability, such as automobile parts and various mechanical parts. The present invention provides a polyamide resin composition that can be widely used for:

(Prior Art) Polyamide resins are in great demand as engineering plastics because of their excellent properties such as moldability, oil resistance, chemical resistance, and heat resistance. However, at present, applications are limited due to poor properties such as impact resistance and flexibility.

Many proposals have been made to improve impact resistance and flexibility. For example, a polyamide resin composition to which a large amount of a plasticizer has been added to impart flexibility has been obtained. Special polyamide resins such as nylon 12, copolymers of various nylons, polyamide elastomers and the like are known as those having improved impact resistance and flexibility, and furthermore, polyolefins, styrene / olefin copolymers and the like are not used. There is also known a composition obtained by modifying a polyamide resin with one modified with a saturated carboxylic acid or the like.

(Problems to be Solved by the Invention) However, such a polyamide resin composition has various problems. The polyamide resin composition containing a large amount of the plasticizer has a disadvantage that the plasticizer flows out and loses its flexibility due to long-term use or use at a high temperature. Nylon 12, copolymers of various nylons, polyamide elastomers and the like are more expensive than other engineering plastics, and their use is limited. In a system in which a modified polyolefin, a modified styrene / olefin copolymer, or the like is blended, as the blending amount increases, the excellent properties inherent in the polyamide resin are lost. That is, moldability is deteriorated, and oil resistance, chemical resistance, and heat resistance are reduced.

Therefore, the present inventors have developed a polyamide resin containing a modified polyester elastomer obtained by reacting a polyester elastomer with a monomer selected from an unsaturated carboxylic acid and an unsaturated carboxylic acid derivative on a widely used polyamide resin. A composition was proposed to solve the above problem.

However, when the composition is melt-molded, the thermal decomposition temperature of the modified polyester elastomer is lower than that of polyamide, so that the composition decomposes, and as a result, the mechanical properties such as tensile elongation of the molded product are reduced. occured.

(Means for Solving the Problems) In order to solve the above-mentioned drawbacks, the present inventors have further diligently
As a result of research and investigation, the present invention has been finally completed. That is, the present invention relates to (A) (a) a diamine containing 70% by mole or more of meta-xylylenediamine, and (b) an α, ω-aliphatic dicarboxylic acid. And (c) a polyamide copolymer obtained from a lactam and / or an aminocarboxylic acid, and (B) a polyester elastomer obtained by reacting a monomer selected from an unsaturated carboxylic acid and an unsaturated carboxylic acid derivative with a polyester elastomer. And a modified polyester elastomer.

The components constituting the polyamide copolymer contained in the composition of the present invention include (a) a diamine containing 70% by mole or more of metaxylylenediamine, (b) an α, ω-aliphatic dicarboxylic acid, and (c) And at least 70 mol% of metaxylylenediamine as a component (a), and the remainder is tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, if desired. Aliphatic diamines such as methylenediamine, octamethylenediamine, nonamethylenediamine; aromatic diamines such as paraxylylenediamine and paraphenylenediamine; 1,3-pisaminomethylcyclohexane, 1,4-pisaminomethylcyclohexane and the like One or more diamines listed as aliphatic diamines may be appropriately selected and used. Can.

As the α, ω-aliphatic dicarboxylic acid as the component (b), aliphatic dicarboxylic acids such as adipic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, etc. Any one or more of the above may be appropriately selected as desired.

Examples of the polyamide-forming component (c) include lactams such as caprolactam, enantholactam and laurin lactam, α, σ amino acids, aminocarboxylic acids such as aminoundecanoic acid, and hexamethylene diammonium adipate and cyclohexanebis ( Nylon salts such as methylammonium) adipate.

The method for producing the polyamide copolymer contained in the present invention is not limited. For example, the components (a) to (c) may be simultaneously added and reacted, or the components (a) and (b) The nylon salt is adjusted in advance with (c)
The components may be added and reacted.

The melting point of the polyamide copolymer used in the present invention is 170 ° C or higher and 230 ° C or lower, and the relative viscosity (according to JIS K6810-1970,
(Measured in 98% sulfuric acid) is preferably 1.8 or more, more preferably 2.0 or more, so that the mixing ratio of the components (a) to (c) may be appropriately selected so as to obtain the polyamide copolymer.

Next, 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,
Poly (oxypropylene) glycol, poly (oxypropylene) glycol, poly (oxytetramethylene)
Glycol is mentioned as a preferred example. 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. Further, a modified polyether having sulfur, nitrogen, phosphorus or 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. As the crystalline aromatic polyester, a polymer mainly having an ester bond or an ester bond and an ether bond. And 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. As the copolymer polyester or copolymerized polyester ether,
A polymer mainly having a tetramethylene terephthalate unit or an ethylene terephthalate unit and further having another copolymerization component is exemplified. Examples of such a copolymer component include a tetramethylene terephthalate unit, an ethylene isophthalate unit, a tetramethylene adipate unit,
Ethylene adipate unit, tetramethylene sebacate unit, ethylene sebacate unit, 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-endocis-bicyclo (2,2,
1) Hept-5-ene-2,3-dicarboxylic acid (methylnadic acid) and the like 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. In particular,
Examples thereof include maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Of these, unsaturated dicarboxylic acids or unsaturated dicarboxylic anhydrides are preferably used, and 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) of the polyamide copolymer (A) and the modified polyester elastomer (B) is preferably from 95/5 to 5/95. More preferably, (A) / (B) is 90/10 to 1
0/90 is recommended. If the weight ratio of the modified polyester elastomer is less than 95/5, the impact resistance, flexibility and the like will not be improved. If the weight ratio of the modified polyester elastomer is more than 5/95, the gas permeability, water resistance, etc. will decrease.

The composition of the present invention may further contain other additives. Examples of the additives include a coloring agent, a stabilizer, an inorganic filler, an organic filler, a fibrous reinforcing agent, and various other auxiliaries. Usually, the polyamide copolymer (A) and the modified polyester elastomer (B) are mixed under heating, and the above-mentioned additives are added at any of the initial stage, the intermediate stage, and the final stage of the mixing. obtain. For the mixing, a conventionally known device can be used. For example, a kneading apparatus 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 copolymer (A) and the modified polyester elastomer (B).

(Operation) The modified polyester elastomer (B) is obtained by subjecting a polyester elastomer to a graft reaction with a modifier selected from unsaturated carboxylic acids and derivatives thereof. It is presumed that, when this is mixed with the polyamide copolymer resin (A) 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. In this way, flexibility and impact resistance can be added while maintaining the excellent properties of the polyamide resin.

Further, by using the polyamide copolymer, processing in a low temperature range becomes possible, the decomposition of the polyester elastomer can be prevented, and the moldability and general mechanical properties can be maintained.

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

In the present embodiment, as the polyamide copolymer, the relative viscosity 2.
12 (in 98% sulfuric acid; 1 g / 100 ml at 25 ° C.) using a copolymer (hereinafter referred to as CoM) obtained by reacting 90 wt% of metaxylylene adipamide with 10 wt% of ε-caprolactam at 100 ° C.
It was used after vacuum drying for 16 hours.

Examples of the polyester elastomer include a polyether-polyester elastomer of polytetramethylene glycol and polytetramethylene terephthalate (Perprene P150B manufactured by Toyobo Co., Ltd.), and a polyester-type block copolymer of polycaprolactone and polytetramethylene terephthalate (manufactured by Toyobo Co., Ltd.) Pelprene S-1000) was used.

In the examples and comparative examples, the tensile properties were measured by the following methods.

Tensile properties Using the obtained sheet molded product, the tensile properties described in JIS-K6301
No. dumbbell test piece was prepared. A test piece was prepared by punching out a dumbbell so that the length direction was perpendicular to the flow direction, and the test sheet provided with the pins was such that the melt-bonded portion was at the center.

The test piece was stretched at a gross head speed of 50 mm / min at right angles to the flow direction according to the method of JIS-K6301, and the load at break was measured. The value obtained by dividing the value by the initial cross-sectional area (cm ² ) was defined as the tensile strength, and the elongation of the sample at break relative to the initial sample length was defined as the tensile elongation (%).

Production Example Maleic anhydride-modified polyester elastomers are 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 4 The above-mentioned copolymerized polyamide resin and the modified polyester elastomers 'and' obtained in the above production examples were dry-blended at the ratios shown in Table 1 and pellets were produced using a 30 mmφ twin-screw extruder. . The cylinder temperature at that time
235 ° C. The obtained pellet was vacuum dried at 70 ° C. for 16 hours.

Using the pellets obtained above, each test sheet was prepared by a sheet extrusion die attached to the tip of a 30 mmφ twin screw extruder. Removable φ1mm for sheet extrusion die
By dividing the flow of the resin once,
It was made possible to prepare a sheet for testing the melt adhesion of the resin.

The cylinder temperature at that time was 235 ° C., and a take-off device was used to obtain a sheet molded product having a width of 12 cm and a thickness of 0.8 mm.

Comparative Examples 1 to 4 Test pieces were prepared in the same manner as in the examples with the compositions shown in Table 1 using polymeta-xylene adipamide (MXD-6) having a relative viscosity of 2.2 as the polyamide resin.

Comparative Examples 5 and 6 The copolyamide resins used in Examples 1 to 4 were used. However, a polyester elastomer which was not modified was used with the composition shown in Table 1.

 The results are shown in Table 1.

(Effects of the Invention) As is clear from Table 1, the test pieces prepared using the copolymerized polyamide resin compositions of Examples 1 to 4 have the same tensile strength as the sample provided with a pin and having a melt-bonded portion. Although there is no part (a sheet made without using pins), the tensile properties are hardly changed. However, in Comparative Examples 1 to 4, those having no bonded portion are the same as Examples 1 to 4, but it can be seen that the tensile properties of the sheet having the fused bonded portion are significantly reduced in both the elongation and the elongation.

In Comparative Examples 5 and 6, the compatibility between the copolymerized polyamide resin and the polyester elastomer was insufficient, and pellets could be prepared. However, sheet molding was not possible due to unstable fluidity, and measurement of tensile properties was impossible. Became.

When extruding tubular molded articles using the compositions of these Examples and Comparative Examples, Examples 1 to 3 were obtained in the same manner as the above results.
Sample No. 4 was excellent in surface gloss and a beautiful tubular body without discoloration was obtained. However, those of Comparative Examples 1 to 4 showed slight discoloration, cracks in the spider portion, and reduced strength.

The polyamide resin composition of the present invention is useful as an engineering plastic because it has excellent mechanical properties, oil resistance, chemical resistance, gas barrier properties, as well as excellent tensile properties and moldability. It can also be formed into fibers, films, sheets, and can be used in a wide range of products from extrusion molded products such as tubes, hoses and belts to injection molded products such as noise reduction gears, greatly contributing to the industry.

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Claims (1)

(57) [Claims] (1) (A) (a) meta-xylylenediamine is added to 70
(B) α, ω-aliphatic dicarboxylic acid and (c) a polyamide copolymer obtained from other polyamide-forming components, and (B) an unsaturated carboxylic acid and an unsaturated carboxylic acid. A polyamide resin composition comprising a modified polyester elastomer obtained by reacting a monomer selected from a derivative with a polyester elastomer.