JPH01141940A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in heat distortion resistance, oil resistance, rigidity and impact resistance and giving a molding having an excellent appearance, by mixing a polyamide resin with an unsaturated carboxylic acid copolymer and a specified graft copolymer. CONSTITUTION:An unsaturated carboxylic acid copolymer (B) is obtained by emulsion-polymerizing 40-80wt.% aromatic vinyl compound (e.g., alpha- methylstyrene) with 15-50wt.% vinyl cyanide compound (e.g., acrylonitrile) and 0.5-40wt.% unsaturated carboxylic acid monomer (e.g., acrylic acid). A graft copolymer (C) is obtained by graft-polymerizing 95-5wt.% vinyl compound comprising 20-80wt.% aromatic vinyl compound, 15-50wt.% vinyl cyanide compound and 0-40wt.% unsaturated carboxylic acid compound in the presence of 5-95wt.% diene rubber of a mean particle diameter of 0.05-2mu. 5-90pts.wt. polyamide resin (A) is mixed with 5-90pts.wt. component B and 5-60pts.wt. component C in amounts to give a total of 100pts.wt.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a novel thermoplastic resin composition that has excellent heat deformation resistance, oil resistance, and excellent rigidity, impact resistance, and surface appearance of molded products. It is related to.

(Conventional technology and problems) Polyamide resin is used in electrical and automobile parts because it has excellent heat deformation resistance, rigidity, oil resistance, etc., but it needs further modification in terms of impact resistance and water resistance. is desired. On the other hand, ABS resin, which is a typical rubber-reinforced resin, has excellent impact resistance and processability, so it is used in automobile, electrical, and miscellaneous parts. Further improvement is desired.

Attempts have been made to blend polyamide resin and ABS resin to take advantage of the characteristics of both, but originally polyamide resin and ABS resin are a combination with very poor compatibility and dispersibility, and molded products of the mixture are shows extreme non-uniformity, resulting in poor surface appearance, delamination, deterioration of impact resistance, etc., which cannot be used for practical purposes. Therefore, by adding compatibilizers and modifying ABS resin, polyamide resin and ABS Attempts have been made to improve the compatibility of resins. For example, a method in which a monomer containing an unsaturated carboxylic acid is graft copolymerized with a rubber component and reacted with the amine end of a polyamide (JP-A-47-6284), and when an unsaturated carboxylic acid is subjected to emulsion graft polymerization, Polymerization stability is poor and a large amount of aggregates are generated.In order to avoid this, unsaturated carboxylic acid ester monomers are graft-polymerized onto rubber-like polymers and then saponified to improve compatibility with polyamide resins. A method has also been proposed to improve the
1) 159).

It is certainly possible to improve the compatibility between polyamide resin and ABS resin by these methods, and impact resistance can also be improved. However, since it requires graft copolymerization, there are many complicated operations such as generation of aggregates and saponification treatment to avoid this, and this method has never been industrially advantageous.

(Means and Effects for Solving the Problems) As a result of intensive research into improving the compatibility of ABS resin with polyamide resin and improving the physical properties, the present inventor has found that an unsaturated carboxylic acid-containing copolymer can be used with polyamide resin and When used with a graft copolymer, it has excellent heat deformation resistance, a good balance of physical properties such as oil resistance, amphoteric properties, impact resistance, surface hardness, paintability, and water resistance, and can be easily molded and has a uniform surface property. We have discovered a new thermoplastic resin composition having the following properties.

The present inventors further developed a copolymer obtained by copolymerizing an aromatic vinyl compound, an unsaturated carboxylic acid, and a vinyl cyanide compound,
To obtain a thermoplastic resin composition which overcomes the above drawbacks and has excellent compatibility by blending an unsaturated carboxylic acid-containing copolymer obtained by blending a rubber-containing graft copolymer with a polyamide resin. The present invention was based on the discovery that this can be done.

That is, the present invention provides 95 to 5 parts by weight of a vinyl compound in the presence of 5 to 90 parts by weight of polyamide resin (A), 5 to 90 parts by weight of unsaturated carboxylic acid-containing copolymer (B), and 5 to 95 parts by weight of diene rubber. Graft copolymer (c) obtained by graft polymerization of 5 to 60 parts by weight ((A) + (B) + (
C) = 100 parts by weight].

The polyamide resin (A) used in the present invention is an aliphatic polyamide, such as polyamide 6, polyamide 6.6, polyamide 6.10. polyamide 1), polyamide 12,
Polyamide 6/12: Aromatic polyamides such as polyhexamethylene dibumine tyrephthalamide, polyhexamethylene diamine isophthalamide, etc. can be mentioned, and mixtures or copolymers of two or more of these can also be used. It is also possible to use a modified polyamide whose impact resistance has been improved by adding acid-modified polyolefin or the like.

In the present invention, an unsaturated carboxylic acid-containing copolymer (B
) is particularly important. The unsaturated carboxylic acid-containing polymer (B) is preferably a copolymer obtained by reacting an unsaturated carboxylic acid monomer, an aromatic vinyl compound, and a vinyl cyanide compound. When reacting these monomeric compounds,
Furthermore, copolymer (B) may be copolymerized by reacting with other copolymerizable vinyl compounds.
% by weight, unsaturated carboxylic acid compound 0.5-40% by weight,
More preferably, a copolymer obtained by reacting 1 to 15% by weight is particularly preferred. At this time, other copolymerizable vinyl compounds may be reacted up to 30% by weight with respect to 100M% of the total monomer, and the aromatic vinyl compound is 80% by weight.
If it exceeds 40%, the oil resistance and impact resistance will deteriorate, which is undesirable, and if it exceeds 40%, the moldability will deteriorate. If the vinyl cyanide compound exceeds 50% by weight, the thermal stability during molding will decrease and coloring will be severe due to heating, and if it is less than 15% by weight, the chemical resistance and impact resistance will decrease. If the content of the unsaturated carboxylic acid compound exceeds 40% by weight, the thermal stability during molding will decrease, and not only will coloring by heating be severe, but also the stability during polymerization will decrease. If it is less than 0.5% by weight, the compatibility with the polyamide resin deteriorates, causing delamination or the like on the surface of the molded product, or a significant decrease in impact resistance is undesirable.

Examples of the aromatic vinyl compound used in the copolymer (B) include styrene, α-methylstyrene, chlorostyrene, and methylstyrene. From the viewpoint of improving heat resistance, it is recommended to use α-methylstyrene.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile. Examples of unsaturated carboxylic acid compounds include acrylic acid and methacrylic acid. Examples of other copolymerizable vinyl compounds include methacrylic acid such as methyl methacrylate, ethyl methacrylate, methyl acrylate, and ethyl acrylate, alkyl esters of acrylic acid, and maleimide compounds such as maleimide and phenylmaleimide. Ru.

The graft copolymer (C) is a graft copolymer obtained by graft copolymerizing 95 to 5% by weight of a copolymerizable vinyl compound with 5 to 95% by weight of a diene rubber.

Aromatic vinyl compounds, vinyl cyanide compounds, unsaturated carboxylic acid compounds, and other vinyl compounds can be used as graft copolymerizable vinyl compounds. Aromatic vinyl compounds, vinyl cyanide compounds, unsaturated carboxylic acid compounds, and other copolymerizable vinyl compounds are
Those shown as copolymers (B) can be used.

The composition of the vinyl compound to be graft copolymerized is preferably 20 to 80% by weight of an aromatic vinyl compound, 15 to 50% by weight of a vinyl cyanide compound, and an unsaturated carboxylic acid compound O.
~40% by weight, and other copolymerizable vinyl compounds O~
It can be selected from a range of 30% by weight.

The diene rubber used in the graft copolymer (C) is not particularly limited, but one with a diene component of 50% by weight or more and an average particle size of 0.05 to 2 μm is preferable.

If the diene rubber exceeds 95 parts by weight, the impact resistance and oil resistance will decrease, and if it is less than 5 parts by weight, the impact resistance will decrease. If the aromatic vinyl compound exceeds 80% by weight, impact resistance, oil resistance, etc. will decrease, and if it is less than 20% by weight, moldability will decrease. Moreover, if the cyanide vinyl compound exceeds 50% by weight, heat coloring occurs during molding, and if it is less than 15% by weight, impact resistance and oil resistance decrease, which is not preferable.

The blending ratio of polyamide resin (A), copolymer (B) and graft copolymer (C) is 5
~90 parts by weight, 5 to 90 parts by weight of copolymer (B), preferably 50 to 80 parts by weight, and 5 parts by weight of graft copolymer (C).
~60 parts by weight, preferably 20 to 50 parts by weight [(
100 parts by weight of A), (B), and (C)]. If the amount of copolymer (B) is less than 40 parts by weight, it is not preferable because body heat deformability and moldability decrease.

The copolymer CB) and the graft copolymer (C) are preferably obtained by emulsion polymerization, but are not necessarily limited to emulsion polymerization. Examples include bulk polymerization, suspension polymerization, solution polymerization, and combinations thereof, ie, emulsion-suspension polymerization and emulsion-bulk polymerization.

Conventional methods can be applied to emulsion polymerization. That is, the above compound may be reacted in an aqueous medium in the presence of a radical initiator. At that time, the above-mentioned compounds may be used as a mixture or, if necessary, may be used separately. moreover,
As for the method of adding the above compound, even if the entire amount is added at once,
Further, they may be added sequentially, and are not particularly limited.

Examples of the radical initiator include water-soluble or oil-soluble peroxides such as potassium persulfate, ammonium persulfate, cumene hydroperoxide, and paramenthane hydroperoxide.

In addition, polymerization accelerators, polymerization degree regulators, and emulsifiers may be appropriately selected from those used in known emulsion polymerization methods.

A known method may be used to obtain a dry resin from the obtained latex. At that time, a dry resin may be obtained after mixing the latexes of the copolymer (B) and the graft copolymer (C), or the resin may be obtained separately and mixed in a powder state. To obtain resin from latex, for example, an acid such as hydrochloric acid, sulfuric acid, or acetic acid, or a metal salt such as calcium chloride, magnesium chloride, or aluminum sulfate is added to latex, the latex is coagulated, and then dried. can be implemented.

Regarding the graft copolymer (C), AB containing a graft copolymer of a vinyl compound of diene rubber
It may be S resin or heat-resistant ABS (MUH) resin. The amount of ABS or MUH resin used at that time is preferably determined by taking into consideration the amount of graft copolymer contained therein.

The characteristics of the thermoplastic resin in the present invention are polyamide resin (
A), the unsaturated carboxylic acid-containing copolymer (B), and the graft copolymer (C) will vary depending on the mixing ratio, but in the present invention, (A) 5 to 90 parts by weight, (B) 5 to 9
Graft copolymer (C) obtained by graft polymerization of 95 to 5% by weight of a vinyl compound in the presence of 0 parts by weight and 5 to 95% by weight of diene rubber ((A) + (B)
) + (C) = 100 parts by weight]. If the polyamide resin (A) is less than 5% by weight, oil resistance will decrease, and if it exceeds 90 parts by weight, water resistance will decrease. If the amount of the unsaturated carboxylic acid-containing copolymer (B) is less than 5 parts, the impact resistance will decrease, and if it exceeds 90 parts by weight, the oil resistance will decrease, which is not preferable.

Mixing, granulation and molding can be carried out by known methods. That is, a polyamide resin, an unsaturated carboxylic acid-containing copolymer, and a graft copolymer are blended using a blender such as a Henschel mixer, and then melt-mixed in an extruder to obtain pellets, which are then subjected to injection molding. Good.

At that time, stabilizers, pigments, lubricants, fillers, etc. may be added as necessary.

(Examples) The present invention will be described below with reference to Examples, but these are merely illustrative and the present invention is not limited thereto. Unless otherwise specified, "parts" are parts by weight,
"%" represents weight %.

Examples and Comparative Examples (a) Production of copolymer (B) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet, monomer inlet, and thermometer, 200 parts of water and 3 parts of sodium dodecylbenzenesulfonate were added. was charged, and the reaction vessel was heated to 60° C. under a nitrogen stream while stirring. Table 1 shows the results after reaching 60°C.

Vinyl compound, t-dodecylmercaptan (tDM)
and cumene hydroperoxide (CHP) were continuously added dropwise over 6 hours. However, for B-1, 75 parts of α-methylstyrene (αMSt) and tD
0.4 part of M was charged in advance into a reaction vessel. After the dropwise addition was completed, stirring was continued for 1 hour at 60°C to complete the polymerization.

(B) Production of graft copolymer (C) The following substances were placed in a reaction vessel similar to (a).

water
250 parts Sodium formaldehyde sulfoxylate 0.3 parts Ferrous sulfate 0.0025 parts Sodium ethylenediaminetetraacetate 0.01 parts Polybutadiene Specified! (Table 2) The reaction vessel was heated to 60° C. under a nitrogen stream while stirring. After reaching 60°C, the number of parts of the compounds shown in Table 2 also shown in Table 2,
Dropped continuously for 5 hours, added 0 drops, then added 6 more after completion of addition.
Stirring was continued for 1 hour at 0°C to complete the polymerization. The polybutadiene used was latex-like with an average particle diameter of 0.025 μm and a gel content of 90%.

(c) Production of blend of unsaturated carboxylic acid-containing copolymer (B) and graft copolymer (C) Copolymer (B) and graft copolymer produced as in (a) and (b) above (C) in latex state Table 3
A phenolic antioxidant is added to this mixed latex, coagulated with calcium chloride, dehydrated, washed with water, and dried to obtain a powder-like unsaturated carboxylic acid-containing copolymer (B). and graft copolymer (C) was obtained.

(d) Production of thermoplastic resin composition A blend of polyamide resin (A), unsaturated carboxylic acid-containing copolymer (B), and graft copolymer (C) (referred to as D) and polyamide resin (A) were mixed in a predetermined ratio shown in Table 4, pelletized using a vent extruder, and a test piece was prepared by injection molding, which was used to measure physical properties. The measurement results of physical properties are also shown in Table 4.

Heat distortion temperature: ASTM D-648, 4,6 dazzle/cd (t) Izod impact value: ASTM D-256, notched (kg・cs/am) Tensile strength: AS
TM D-636, 23℃ (kg/CIJ) Elongation at break: ASTM D-636, 23℃ (
%) Surface properties of molded products A flat plate of 150 m x 100 m x 3 m was injection molded, and its appearance was visually observed to evaluate surface uniformity, flow marks, coloring, etc.

Good...○, Fairly bad...Δ, Bad.
...× Oil resistance: The above flat plate was immersed in toluene and DOP for 10 days at room temperature, and changes in its appearance were observed.

From Examples 1 to 1) and Comparative Examples 1 to 2 shown in Table 4.5, the thermoplastic resin composition of the present invention has excellent heat deformation resistance, and good oil resistance, rigidity, impact resistance, and surface appearance. I understand something.

(Margin below) Table 2

Claims (2)

[Claims] (1) 95 to 95 parts by weight of a vinyl compound in the presence of 5 to 90 parts by weight of polyamide resin (A), 5 to 90 parts by weight of unsaturated carboxylic acid-containing copolymer (B), and 5 to 95% by weight of diene rubber.
A thermoplastic resin composition comprising 5 to 60 parts by weight of a graft copolymer (C) obtained by graft polymerization of 5% by weight [100 parts by weight in total of (A), (B), and (C)]. (2) The unsaturated carboxylic acid-containing copolymer (B) contains 40 to 80% by weight of an aromatic vinyl compound and 1% by weight of a vinyl cyanide compound.
5-50% by weight and 0.5-4 unsaturated carboxylic acid monomers
The thermoplastic resin composition according to claim 1, which is a copolymer obtained by reacting 0% by weight.