JPH0737562B2 - Thermoplastic resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a thermoplastic resin composition containing a polyamide, a polyphenylene ether and a butadiene-styrene block copolymer as main constituents. More specifically, the present invention provides that the three components constitute a blend in a specific dispersion form, that is, heat deformation resistance, impact resistance,
The present invention relates to a thermoplastic resin composition having an excellent balance of oil resistance, rigidity, molding fluidity and the like.

2. Description of the Related Art Conventionally, polyamide resins are excellent in mechanical strength, oil resistance, wear resistance, heat resistance and the like, and are used in large amounts as one of the most representative engineering plastics. However, this polyamide resin has the drawback that it has lower properties such as dimensional stability, hygroscopicity, thermal deformation resistance under high load, and impact resistance during drying as compared with other plastics.

On the other hand, polyphenylene ether resin is a resin with excellent dimensional stability, electrical characteristics, heat distortion resistance under high load, water resistance, etc., and is industrially blended with polystyrene type resin. Although widely used, this polyphenylene ether resin has the major drawback of being inferior in oil resistance and molding fluidity.

In this way, taking advantage of the respective advantages of both resins,
Blending of both resins has been attempted for the purpose of complementing the drawbacks of both, and many compositions have been proposed so far. As such a material, there is a blend in which both resins are simply blended, particularly a blend obtained by melt mixing (Japanese Patent Publication No. 45-997 and Japanese Patent Publication No. 59-4163), but the polyphenylene ether and the polyamide are essentially compatible with each other. It is difficult to do so, and such a simple blend cannot obtain a molded article excellent in mechanical strength.

Also, with polyphenylene ether and polyamide,
A composition is also known in which a copolymer of a styrene compound and an α, β-unsaturated dicarboxylic acid anhydride is blended as a compatibility improving agent, and a rubber-like substance is added as an impact resistance improving agent. JP-A-59-33614). However, in this composition, it is recognized that the improved compatibility improves mechanical properties and oil resistance, but the connection state of both resins via the compatibility improver (probably due to a graft reaction Is excessive, and the dispersion between the two resins becomes extremely fine, resulting in a marked decrease in molding fluidity, and insufficient improvement in heat distortion resistance under high load.

Furthermore, in addition to polyamide and polyphenylene ether, a compound having a carbon-carbon double bond or triple bond in the molecule (a) and (b) a functional group such as a carboxyl group or an acid anhydride group is added, and the mixture is melt-kneaded. A method for producing a modified polymer by the method (Japanese Patent Publication No. 60-11966) and a composition in which a rubber-like substance is further added (Japanese Patent Laid-Open No. 56-49753) are also proposed. Since the dispersion of the phenylene ether part and the polyamide part is finely divided, there are drawbacks that sufficient impact strength cannot be obtained and molding fluidity is poor.

Under such circumstances, the object of the present invention is to provide a blend system of polyamide and polyphenylene ether with heat distortion resistance, impact resistance, oil resistance, rigidity and molding fluidity. It is intended to provide a thermoplastic resin composition having an excellent balance of the above.

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a polyamide, a polyphenylene ether and a butadiene-styrene block copolymer as a reinforcing agent are contained at a predetermined ratio. It was found that the object can be achieved by adding a maleic acid compound to the resin component obtained by controlling the dispersion morphology of these three components to a specific state, and the present invention is completed based on this finding. Was reached.

That is, the present invention provides (A) polyamide 25 to 70% by weight,
(B) Polyphenylene ether 25-70% by weight and (C)
A resin composition comprising 0.05 to 2 parts by weight of a maleic acid compound (D) with respect to 100 parts by weight of a resin component comprising 2 to 25% by weight of a butadiene-styrene block copolymer, wherein the polyamide forms a continuous phase. Polyphenylene ether is dispersed in the continuous phase as a dispersed phase having an average particle size of 2.1 μm or more and 10 μm or less, and substantially all of the butadiene-styrene block copolymer is microdispersed in the polyphenylene ether dispersed phase. To provide a thermoplastic resin composition.

The polyphenylene ether used in the composition of the present invention has the general formula (Here, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ are the same or different tert-
It is a monovalent residue such as an alkyl group having 1 to 4 carbon atoms excluding a butyl group, an aryl group, halogen, hydrogen, and R ₅ and R ₆ are not hydrogen at the same time. ) Is a repeating unit, and the structural unit is [I] or a homopolymer or copolymer of [I] and [II], and a graft copolymer obtained by graft-polymerizing styrene or the like to the polymer.

Typical examples of polyphenylene ether homopolymers include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly ( 2,6-diethyl-1,4-phenylene) ether, poly (2-ethyl-6-npropyl-1,
4-phenylene) ether, poly (2,6-di-n-propyl-1,4-phenylene) ether, poly (2-methyl-6)
-N-butyl-1,4-phenylene) ether, poly (2-
Ethyl-6-isopropyl-1,4-phenylene) ether, poly (2-methyl-6-chloro-1,4-phenylene) ether, poly (2-methyl-6-hydroxyethyl-1,4-phenylene) ether , Poly (2-methyl-
Homopolymers such as 6-chloroethyl-1,4-phenylene) ether are mentioned.

Polyphenylene ether copolymer is orthocresol or general formula (Here, R ₃ , R ₄ , R ₅ , and R ₆ are carbon number 1 excluding tert-butyl group.
~ 4 are monovalent residues such as an alkyl group, an aryl group, halogen and hydrogen, and R ₅ and R ₆ are not hydrogen at the same time. ), A polyphenylene ether copolymer mainly composed of a polyphenylene ether structure obtained by copolymerization with an alkyl-substituted phenol such as 2,3,6-trimethylphenol.

The polyamide used in the composition of the present invention has a polymer main chain. Any material having a bond and capable of being melted by heating is possible.

Typical examples are 4-nylon, 6-nylon, 6,6-nylon, 12-nylon, 6,10-nylon,
Polyamides from terephthalic acid and trimethylhexamethylenediamine, polyamides from adipic acid and metaxylylenediamine, adipic acid and azelaic acid and 2,2-
Examples include polyamides from bis (p-aminocyclohexyl) -propane, polyamides from terephthalic acid and 4,4'-diaminodicyclohexylmethane. Among these, especially 6-nylon, 6,6-nylon, 6,10-
Nylon is preferred.

The butadiene-styrene block copolymer used in the composition of the present invention is elastomeric at room temperature, and substantially all of it is microdispersed in the polyphenylene ether phase existing as a dispersed phase in the composition. In addition, it must have an affinity for polyphenylene ether rather than polyamide.

The blending ratio of polyamide, polyphenylene ether and butadiene-styrene block copolymer in the composition of the present invention is such that the total amount of these three components is 25 to 70% of polyamide.
% By weight, preferably 30-50% by weight, polyphenylene ether 25-70% by weight, preferably 40-60% by weight and butadiene-styrene block copolymer 2-25% by weight, preferably 5%.
~ 20% by weight.

Further, regarding the dispersion form of each component, the polyamide forms a continuous phase, and the polyphenylene ether is dispersed in the continuous phase so that the average particle size is more than 2.1 μm and 10 μm or less, preferably 3 to 7 μm. In addition to forming the phase, it is necessary that substantially all of the butadiene-styrene block copolymer be microdispersed in the dispersed phase polyphenylene ether.

When the polyamide is less than 25% by weight or the polyphenylene ether is more than 70% by weight with respect to the total amount of the three components, the polyamide is the continuous phase and the polyphenylene ether is the dispersed phase under any mixing condition. On the other hand, when the polyamide content exceeds 70% by weight or the polyphenylene ether content is less than 25% by weight, the composition is inferior in heat deformation resistance under high load, which is not preferable. Further, the butadiene-styrene block copolymer is necessary for improving impact resistance, and if the content is less than 2% by weight, there is no effect of improving impact resistance, while if it exceeds 25% by weight, mechanical strength is increased. descend.

Further, the dispersion form of each component is as described above, when the polyamide forms a dispersed phase, or when both the polyamide and the polyphenylene ether form a continuous phase,
The oil resistance and molding fluidity of the composition decrease, and when the dispersed phase of polyphenylene ether has an average particle diameter of 2.1 μm or less, impact resistance, heat distortion resistance and molding fluidity decrease, and more than 10 μm. It becomes difficult to form a dispersed phase in a stable state even under severe molding conditions, and when a large amount of butadiene-styrene block copolymer is independently present in the polyamide phase, the thermal denaturation temperature and rigidity are significantly reduced. For the reason.

Next, a general method for producing the composition of the present invention will be described. Of course, other production methods can be used as long as the above-mentioned conditions are satisfied.

That is, the composition of the present invention, polyamide, polyphenylene ether and butadiene-styrene block copolymer, relative to the total amount of these 25-70 wt%, 25
It is obtained by melt-kneading in a proportion of 70 to 70% by weight and 2 to 25% by weight, in which case it is substantially necessary to use a maleic acid compound and a specific amine compound in combination as a dispersion morphology modifier. . Examples of the maleic acid compound include maleic acid, maleic anhydride, half-alkyl ester of maleic acid, maleic acid amide, and maleic acid imide. Of these, maleic acid and maleic anhydride are preferable. The amount of this maleic acid compound added is
It is selected in the range of 0.05 to 2% by weight, preferably 0.1 to 1% by weight, based on the total amount of the three components. Further, the specific amine compound is a compound having at least one nitrogen atom and a sulfur atom in the molecule, and examples thereof include phenothiazine, an alkyl group having 1 to 30 carbon atoms, and an alkenyl group. , A phenothiazine derivative having a substituent such as an aryl group, an amide group and an acyl group. The amount of these amine compounds added is 0.05 to 2% by weight, preferably 0.1 to 1% by weight, based on the total amount of the above three components.
It is selected in the range of. The amount of the maleic acid compound added is 0.05
If it is less than 10% by weight, the average particle size of the dispersed phase exceeds 10 μm, and if it exceeds 2% by weight, the average particle size tends to be 2.1 μm or less, which is not preferable. On the other hand, the amine-based compound particularly affects the dispersion form of the butadiene-styrene block copolymer, and if the addition amount is less than 0.05% by weight, the butadiene-styrene block copolymer is sufficiently microscopic in the polyphenylene ether phase. It is no longer necessary to disperse and to exceed 2% by weight.

The temperature and time for melt-kneading differ depending on the type of polyamide used and the composition ratio of polyamide and polyphenylene ether, but are usually 240 to 350 ° C., preferably 260
Temperatures in the range of ~ 320 ° C, but also 0.2-10 minutes, preferably 0.
A kneading time of about 5 to 5 minutes is used. As the melt-kneading device, an extruder, a kneader, a roll or the like can be used, but an extruder is particularly suitable.

The composition of the present invention may include other polymers, plasticizers,
A flame retardant or a filler such as glass fiber, carbon fiber, carbon black, silica or clay may be added within a range not impairing the object of the present invention. The other polymer is preferably a polymer that is substantially compatible with the polyphenylene ether phase, and examples thereof include polystyrene and rubber-modified polystyrene.

In addition, the dispersion form and the dispersed particle diameter in the present invention can be determined by an electron micrograph, and the dispersed particle diameter can be calculated as follows.

That is, a transmission electron micrograph of an ultrathin section cut out from a molded product (photograph magnification: 4000 times) was prepared, and dispersed particle size di
The number ni of particles is obtained, and the average diameter of the dispersed phase is calculated by the following formula.

In this case, when the particle shape cannot be regarded as spherical, the minor axis and major axis were measured, and 1/2 of the sum of the two was taken as the particle diameter.
Moreover, the diameter of at least 2000 particles is measured to calculate the average particle diameter.

EFFECTS OF THE INVENTION The thermoplastic resin composition of the present invention has polyamide, polyphenylene ether, and butadiene-styrene block copolymer as main constituents, and these three constituents have a specific dispersion form. As a result, it has physical properties that are well-balanced in terms of heat distortion resistance, impact resistance, oil resistance, rigidity, molding fluidity, etc., as compared with conventional ones.

EXAMPLES Next, the present invention will be described in more detail with reference to examples.

Examples 1 to 3, Comparative Examples 1 to 6 Poly (2,6-dimethylphenylene-1,4-ether) having an intrinsic viscosity of 0.62 (in chloroform at 25 ° C.), 6,6-
Nylon, SB block polymer with 40% bound styrene, maleic anhydride, and phenothiazine were supplied to a 30φ twin-screw extruder according to the compounding recipe shown in Table 1, extrusion kneaded at a temperature of 300 ° C., and pelletized. Then, a test piece was prepared with an injection molding machine, and the characteristics were evaluated according to the following test methods.

Heat distortion temperature: JIS K 7207 Weighted 18.6kg / cm ² Izod impact strength With notch: JIS K 7110 1/4 ″ thickness Bending elastic modulus: ASTM-D 790 Flow: Shottute at dumbbell test piece molding at 290 ℃ Molding pressure Oil resistance: Condition of appearance of molded products after exposure to vapor of 1,1,1-trichloroethane for 5 minutes From the results shown in Table 1, Examples 1 to 3 show thermal deformation resistance temperature, impact resistance, It can be seen that the rigidity and oil resistance are excellent, and the fluidity of the polymer is also good, whereas in Comparative Example 1, the SB block polymer is largely independent and dispersed in the nylon phase, and the heat distortion temperature, Inferior in rigidity and fluidity In Comparative Example 2, the dispersion diameter of polyphenylene ether was small,
The heat distortion temperature and the impact resistance are inferior, and in Comparative Example 3, the polyphenylene ether phase also forms a continuous phase, and the oil resistance and fluidity are very poor.

In Comparative Example 4, the polyphenylene ether content is low, and the heat distortion temperature and rigidity are low. In Comparative Example 5, since the SB block polymer was not included, the impact resistance was poor, and in Comparative Example 6, the compatibility was poor and the average dispersion diameter of the polyphenylene ether was large, and the impact strength was very low.

Examples 4 to 7 Table 2 shows the results of evaluation of physical properties when the compositions of polyphenylene ether 6,6-nylon and SB block polymer were changed as shown in Table 2 with the same components as in Example 1.

From the results shown in Table 2, all of Examples 4 to 7, which are within the range of the composition of the present invention, have an excellent balance of heat distortion temperature, impact resistance, rigidity, flow, and oil resistance. I understand.

Example 8 The 6,6-nylon of Example 1 was pelletized and evaluated under exactly the same composition and conditions except that it was changed to 6-nylon. The results are shown in Table 3.

Similar to 6,6-nylon, 6-nylon can be obtained with excellent balance.

Reference Example The evaluation was carried out by pelletizing under the completely same composition and conditions except that the SB block polymer of Example 1 was changed to high trans polybutadiene (trans bond 80%). The results are shown in Table 4.

Even if high trans polybutadiene is used as the rubber, it is possible to obtain a rubber having an excellent balance of physical properties.

In addition, the transmission electron microscope photographs of the compositions of Example 1, Comparative Example 1 and Comparative Example 2 (magnification: 4000 times) are shown in FIG. 1, FIG. 2 and FIG. 3, respectively.

In both figures, the white continuous phase is nylon, the black one is the butadiene-styrene block copolymer phase, and the middle dark black phase is the polyphenylene ether phase.

In FIG. 1, it can be seen that the polyphenylene ether phase is dispersed in the white nylon phase and the butadiene-styrene block copolymer phase is evenly micro-dispersed therein.

In FIG. 2, a butadiene-styrene block copolymer phase, a polyphenylene ether phase, and a phase in which the polyphenylene ether and the butadiene-styrene block copolymer are nonuniformly dispersed are seen in the white nylon continuous phase.

In FIG. 3, it can be seen that the polyphenylene ether phase containing the butadiene-styrene block copolymer is very finely dispersed in the white nylon phase.

[Brief description of drawings]

FIG. 1, FIG. 2 and FIG. 3 are reproduction electron micrographs showing the microstructure of the compositions of Example 1, Comparative Example 1 and Comparative Example 2, respectively.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location C08L 77/00 LQS LQV (56) Reference JP-A-63-118365 (JP, A) JP-A-SHO 62-273254 (JP, A) International publication 85/05372 (WO, A)

Claims (1)

[Claims] 1. A resin component consisting of (A) 25 to 70% by weight of polyamide, (B) 25 to 70% by weight of polyphenylene ether, and 2 to 25% by weight of (C) butadiene-styrene block copolymer, relative to 100 parts by weight of a resin component. (D) Maleic acid compound 0.05 to
A resin composition containing 2 parts by weight, wherein the polyamide forms a continuous phase, in which the polyphenylene ether is dispersed as a dispersed phase having an average particle size of 2.1 μm or more and 10 μm or less, and further butadiene-styrene. A thermoplastic resin composition, wherein substantially all of the block copolymer is microdispersed in a polyphenylene ether dispersed phase.