JPH0598111A - Resin composition - Google Patents

Abstract

PURPOSE:To reduce water absorption properties and to improve stress cracking properties while maintaining mechanical properties of polyamide resin. CONSTITUTION:100 pts.wt. total amounts of (A) 95-10wt.%, preferably 90-40wt.% polyamide resin (e.g. nylon 6 or nylon 66) and (B) 5-90wt.%, 10-60wt.% thermoplastic polyester (e.g. polyethylene terephthalate or polybutylene terephthalate) are blended with (C) 0.5-50 pts.wt., preferably l-20 pts.wt. methacrylimide-containing polymer containing >=10 % methacrylimide unit of the formula (R is H, 1-20C aliphatic, aromatic or alicyclic hydrocarbon). The composition is optionally mixed with (D) 1-50 pts.wt. metal ion-containing ethylene copolymer.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Polyamide resins are used in a wide range of fields such as mechanical parts and electric / electronic parts by taking advantage of their excellent mechanical properties. However, due to the water absorption property of the polyamide resin, there is a drawback that stress cracks due to metal halide salts are likely to occur at the same time as dimensional changes and physical properties changes, and its application to the precision parts field, automobile field, etc. is practically restricted. It had been.

According to the present invention, by maintaining the excellent properties of polyamide resin and reducing the water absorption, it is possible to suppress the dimensional change and the change of physical properties to be small and at the same time improve the stress cracking property against metal halide salts. ,
It is intended to provide a resin composition that can be applied to the field of precision parts and the field of automobiles.

[0003]

2. Description of the Related Art As a method for reducing the hygroscopicity of a polyamide resin, it is known to incorporate a modified polyolefin. However, the modified polyolefin has an unfavorable thermal property, and this polymer blend has a new problem that the excellent heat resistance of the polyamide resin is deteriorated.

On the other hand, although attempts have been made to blend a thermoplastic polyester having a high heat resistance of the resin itself, the thermoplastic polyester has extremely poor compatibility with the polyamide resin, and the resulting resin composition is Since the mechanical properties are inferior and the molded product obtained by injection molding has the drawback of exhibiting a delamination phenomenon, it is difficult to obtain a composition that can be used practically.

Therefore, the compatibility between the polyamide resin and the thermoplastic polyamide resin may be improved by adding a modified polyolefin (JP-A-61-213256) or a polyepoxy compound (JP-A-51-105355). Attempts have been made to improve the. However, in these methods, the thermal stability at the time of melt processing is lowered, and the mechanical properties of the obtained molded product are not sufficient.

Separately, a method of using a metal ion-containing ethylene copolymer in a polymer blend of this type has been proposed (Japanese Patent Laid-Open No. 1-215853), but the mechanical properties of the molded product are considerably improved. However, there is a problem in that the stress crack resistance against metal halide salts is not sufficient.

[0007]

The object of the present invention is to improve the compatibility of a composition comprising a polyamide resin and a thermoplastic polyester resin, thereby maintaining the excellent properties of the polyamide resin and at the same time absorbing water. It is intended to provide a resin composition which can be applied to the field of precision parts and the field of automobiles by reducing stress crack resistance against metal halide salts.

[0008]

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of extensive studies in order to achieve the above object.

That is, the present invention is based on the following general formula for 100 parts by weight of a resin composition comprising (a) a polyamide resin of 95 to 10% by weight and (b) a thermoplastic polyester resin of 5 to 90% by weight.

[0010]

[Chemical 2]

At least 10% by weight of (c) methacrylimide unit represented by the formula: wherein R represents a hydrogen atom or an aliphatic, aromatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms. The resin composition comprises 0.5 to 50 parts by weight of the methacrylimide-containing polymer.

The present invention will be described in detail below.

The polyamide in the present invention means various polyamide resins obtained by polycondensation of a lactam having three or more membered rings, ω-aminocarboxylic acid, dibasic acid and diamine.

Specifically, nylon 4, nylon 46,
Nylon 6, Nylon 66, Nylon 11, Nylon 1
2, nylon 610, nylon 611, nylon 612
Examples thereof include aliphatic polyamide resins such as, polyhexamethylene terephthalamide, aromatic polyamides such as polyhexamethylene isophthalamide, and mixtures and copolymers of two or more of these.

Among the polyamide resins listed above, nylon 6 and nylon 66 are particularly preferable.

The thermoplastic polyester resin in the present invention means a glycol component having 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol and hexanediol, and a dicarboxylic acid component. Examples of the thermoplastic polyester resin include a terephthalic acid, an isophthalic acid, a halogenated nucleus-substituted product thereof, and an alkyl nucleus-substituted product thereof.

Specifically, in addition to polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyhexylene terephthalate, polyethylene naphthalene dicarboxylate, polybutylene naphthalene dicarboxylate, polyethylene isophthalate / terephthalate, polybutylene isophthalate. / Co-polyesters such as terephthalate, polybutylene terephthalate / decane dicarboxylate and the like. Of these, polyethylene terephthalate and polybutylene terephthalate, which are well balanced in mechanical strength and moldability, are preferred.

The blending ratio of the polyamide resin and the thermoplastic polyester resin is 95 to 10% by weight of the polyamide resin.
(Preferably 90 to 40% by weight), thermoplastic polyester resin 5 to 90% by weight (preferably 10 to 60% by weight)
Is.

When the polyamide resin exceeds 95% by weight, the effect of lowering the water absorption is small, and when it is less than 10% by weight, the mechanical properties unique to the polyamide resin such as toughness and abrasion resistance disappear. It is preferable because it does.

The methacrylimide-containing polymer blended with the polyamide resin and the thermoplastic polyester resin is
It is a polymer or copolymer containing a cyclic imide unit represented by the general formula (I).

A methacrylimide-containing polymer having any chemical structure can be used as long as it contains 10% by weight or more of the cyclic imide unit. Generally, R is a hydrogen atom or a methyl, ethyl, propyl, butyl or phenyl group.

The method for producing the methacrylimide-containing polymer is not particularly limited. For example, polymethylmethacrylate and ammonia or a primary amine such as methylamine or ethylamine is used as a suitable solvent (for example, aromatic hydrocarbon such as benzene, toluene, xylene, ethylbenzene or an alcohol such as methanol, ethanol, propanol or the like alone or from them). A method of forming an imide ring by heating and reacting at 170 to 350 ° C. in an autoclave using two or more selected mixed solvents) is useful. Alternatively, the reaction may be carried out in an extruder as described in JP-A-52-63989.

The cyclic imide unit represented by the general formula (I) must be contained in at least 10% by weight based on the polymer, and if the amount is less than 10% by weight, the heat resistance of the methacrylimide polymer originally has. I can't exercise my ability.

These methacrylimide-containing polymers used in the present invention are 0.5 to 50 parts by weight (preferably 1 to 20 parts by weight) with respect to 100 parts by weight of a mixture of a polyamide resin and a thermoplastic polyester resin. Be compounded. When the amount is less than 0.5 part by weight, the effect of increasing the compatibility between the polyamide resin and the thermoplastic polyester resin is small, and only those having poor mechanical properties can be obtained. Also, 5
If it exceeds 0 parts by weight, the fluidity at the time of molding becomes extremely poor, which is not preferable.

The mixing of the polyamide resin with the thermoplastic polyester resin and the methacrylimide-containing polymer is not particularly limited, and specifically, they are simultaneously mixed by a known melt-kneading method such as a Banbury mixer, an extruder or a super mixer. There is a method of doing. Above all, it is recommended to melt-mix with an extruder at a resin temperature of 220 to 300 ° C.

Further, in order to further improve the compatibility between the polyamide resin and the thermoplastic polyester resin, it is possible to mix the metal ion-containing ethylene copolymer at the same time.

Here, the metal ion-containing ethylene copolymer is a copolymer of ethylene and an unsaturated carboxylic acid such as acrylic acid or methacrylic acid to which a metal ion such as sodium, zinc or magnesium is bound. That is, what is generally called an ionomer. Examples of the product include an ionomer resin manufactured by DuPont (trade name: Surlyn) and an ionomer resin manufactured by Mitsui-DuPont Polychemical (trade name: High Milan).

The metal ion-containing ethylene copolymer is a mixture of a polyamide resin and a thermoplastic polyamide resin.
When 1 to 50 parts by weight are blended at the same time with respect to parts by weight, mechanical properties such as tensile elongation at break are improved as a product (composition).

When only the metal ion-containing ethylene copolymer is used as the compatibilizing agent for the polyamide resin and the thermoplastic polyester resin, the compatibility is improved and the mechanical properties are improved, but the long-term thermal stability is improved. At the same time, the stress crack resistance against the metal halide is not sufficiently improved.

When a methacrylimide-containing polymer is used, these problems are solved. Further, when the metal ion-containing ethylene copolymer and the methacrylimide-containing polymer are used as a mixture, the stress crack resistance against the metal halide salt is improved, and at the same time, the mechanical properties such as tensile elongation at break are also improved.

In the composition of the present invention, in addition to the above-mentioned composition,
Various well-known additives such as glass fiber, carbon fiber, reinforcing agents such as metal whiskers, silica, alumina, silica-alumina clay mineral, silica-magnesium clay mineral, calcium silicate, calcium carbonate, carbon black, etc. Fillers, other lubricants, nucleating agents, antioxidants,
One or more additives such as flame retardants, antistatic agents and plasticizers may be contained.

[0032]

The present invention will be described in more detail with reference to the following examples.

(1) Measurement items were measured by the following method. (A) Tensile strength / elongation at break: Measured according to ASTM D-638. (B) Water absorption rate: A dried disc test piece having a diameter of 50 mm and a thickness of 3 mm was immersed in water at 23 ° C. for 24 hours, and the weight change before and after that was measured. (C) Calcium chloride resistance: width 12.6 mm, thickness 3 mm,
A test piece with a length of 62 mm is immersed in warm water at 80 ° C for 4 hours,
After absorbing water, the test piece was attached to a stainless test piece holder having a width of 5 cm as shown in FIG.

After that, it was immersed in an aqueous calcium chloride solution having a concentration of 30% by weight at 23 ° C. for 1 hour, immediately transferred to a hot air dryer kept at 100 ° C., and treated for 2 hours. After the completion, the test piece was washed with water and the state of cracks in the arm bending portion was judged to be the next rank from the appearance.

⊚: No cracks at all ◯: Cracks are slightly seen in the bent portion of the arm Δ: Many cracks are seen in the bent portion of the arm ×: Cracks are seen on the entire surface XX: Destruction due to cracks

(2) Method for measuring imidization amount of methacrylimide-containing polymer and synthesis example (a) Method for measuring imidization amount The nitrogen content was measured by elemental analysis (measuring machine CHN coder <NT-3> manufactured by Yanagimoto Seisakusho). I asked. Proton NMR JN
M-FX-100 (JEOL) Spectrometer 10
It was measured at 0 MHz.

The imidization amount as used herein means the following general structural formula (II)

[0038]

[Chemical 3]

Assuming a repeating structure of a methacrylimide ring structural unit and a methyl methacrylate unit represented by
Was used as the imidization amount. The value of X is obtained by measuring the nitrogen content by elemental analysis, and from N--CH ₃
Methyl absorption and - (O-CH ₃₎ Methyl absorption was determined by measuring the. (B) Synthetic Example A 2-liter autoclave reactor equipped with a stirrer equipped with a sample injection container was charged with a methyl methacrylate polymer (PMMA,
Intrinsic viscosity 0.50: 0.5% by weight of sample in chloroform solution at 25 ° C.) 100 parts by weight, 80 parts by weight of toluene, 20 parts by weight of methanol were added, the temperature was raised to 250 ° C., and after dissolution with stirring, methylamine 21. Add 7 parts by weight (mol = 0.7 to methyl methacrylate unit in PMMA),
The reaction was carried out at an internal pressure of 50 kg / cm ² G for 4 hours. After completion of the reaction, a methacrylimide-containing polymer (A) was obtained. As a result of measuring the imidization amount (%) of this polymer (A) by the above method, the imidization amount (%) was 70%.

[0040]

Examples 1 to 5 Nylon 6 (m
-Using intrinsic viscosity 1.34) in cresol and using polyethylene terephthalate as a thermoplastic polyester resin <
Abbreviated as PET> (Intrinsic viscosity 0.71 in o-chlorophenol) or polybutylene terephthalate <PB
Abbreviated as T> (o-chlorophenol has an intrinsic viscosity of 0.8
75), and using the methacrylimide-containing polymer (A) obtained in the above-described synthesis example as the methacrylimide-containing polymer, adjusting the compounding ratio shown in Table 1 to prepare a 30 mm diameter twin-screw extruder. In a machine, the resin temperature was melted and mixed within the range of 240 to 280 ° C, and then pelletized.

Using the pellets, a test piece was molded by a 25 mm diameter screw type injection molding machine. Molding is set within a cylinder temperature range of 240 to 280 ° C and a mold temperature of 6
Molding was performed at 0 ° C.

[0042]

Examples 6 to 7 In addition to the methacrylimide-containing polymer (A) as a compatibilizer, an ionomer resin (trade name: Himilan 1706) manufactured by Mitsui DuPont Polychemical Co., Ltd. was further used as a metal ion-containing ethylene copolymer. Was simultaneously compounded with the composition shown in Table 1 and molded in the same manner as in Examples 1 to 5.

[0043]

Comparative Examples 1 to 3 Molding was performed in the same manner as in Examples 1 to 5 except that the methacrylimide-containing polymer (A) was omitted.

[0044]

Comparative Examples 4 to 5 Examples 6 to 7 having compositions shown in Table 1 using only the metal ion-containing ethylene copolymer as a compatibilizer.
Molding was performed in the same manner as in.

The injection-molded articles of the resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5 thus obtained were tested for tensile strength, tensile elongation at break, water absorption rate, and calcium chloride resistance by the methods described above. The measurement was performed. The results are also shown in Table 1.

[0046]

[Table 1] As is clear from Table 1 above, it is understood that each of the examples shows high mechanical properties, low water absorption and excellent calcium chloride resistance.

From this, the methacrylimide-containing polymer is
It was confirmed that the ability of the polyamide and polyester as a compatibilizing agent was effectively exhibited. On the other hand,
All of the corresponding Comparative Examples 1 to 3 are inferior in mechanical properties.

Further, when only the metal ion-containing ethylene copolymer was used as the compatibilizing agent shown in Comparative Examples 4 to 5, although the effect of improving the mechanical properties was observed, the methacrylimide-containing polymer was excellent in calcium chloride resistance. It was clearly inferior to the system using.

[0049]

EFFECTS OF THE INVENTION By blending a methacrylimide-containing polymer with a resin composition comprising a polyamide and a thermoplastic polyester, excellent properties of the polyamide resin are maintained, low water absorption is achieved, and calcium chloride resistance is improved. An excellent resin composition can be obtained.

From the above, the resin composition of the present invention can be applied to a wide range of applications such as precision parts and automobile parts.

[Brief description of drawings]

FIG. 1 is a schematic view (perspective view) of a test piece used in an example and a holder for mounting the test piece.

[Explanation of symbols]

 10 Holder-12 Test piece

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08L 77:00 9286-4J 23:26) 7107-4J (C08L 77/00 67:02 8933-4J 23:26) 7107-4J

Claims (2)

[Claims] 1. (a) 95 to 10% by weight of polyamide resin
And 100 parts by weight of a resin composition comprising (b) 5 to 90% by weight of a thermoplastic polyester resin, the following general formula: (Wherein R represents a hydrogen atom or an aliphatic, aromatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms) (c) Methacrylimide containing at least 10% by weight of a methacrylimide unit. Containing polymer 0.5 to 50
A resin composition containing 1 part by weight. 2. A resin composition comprising the resin composition according to claim 1 and 1 to 50 parts by weight of a metal ion-containing ethylene copolymer.