JPH06136202A - Polypropylene resin composition and its production - Google Patents

Abstract

PURPOSE:To obtain a polypropylene resin composition having high stiffness and excellent in heat resistance, oil resistance, chemical resistance and especially in impact resistance. CONSTITUTION:The polypropylenic resin composition consists of (a) 95-51wt.% polypropylene resin, (b) 4.5-48.9wt.% polystyrene resin and (c) 0.1-4.9% polyphenylene ether resin, where (c)/((b)+(c)) <=0.1, and is obtained by adding (d) 1-40 pts.wt. block copolymer having >=1 aromatic vinyl polymer block and >=1 conjugated diene polymer block, in which >=70% double bonds are hydrogenated, to 100 pts.wt. sum of (a) the polypropylene resin, (b) the polystyrene resin and (c) the polyphenylene ether resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polypropylene resin in which a polystyrene resin is uniformly finely dispersed in a polypropylene resin, has high rigidity, and is excellent in heat resistance, oil resistance, chemical resistance, and particularly impact resistance. It relates to a composition.

[0002]

2. Description of the Related Art Polypropylene has excellent chemical resistance, solvent resistance, heat resistance, moldability and the like, and is widely used in various industrial fields such as electric products and automobile parts. However, since polypropylene is a crystalline resin, it has a large molding shrinkage rate, which causes sink marks on molded pieces and lacks dimensional stability.
The rigidity may be insufficient. On the other hand, polystyrene has high rigidity and is an amorphous resin, and therefore has good dimensional stability, but lacks chemical resistance and solvent resistance. Therefore, in order to complement the drawbacks of these resins, resins have been melt-kneaded to obtain resins, but these resins have poor compatibility, and therefore physical properties are significantly deteriorated, so that they can be put to practical use. Not a thing. In order to improve the compatibility of these two resins, a composition comprising a styrene-conjugated diene block copolymer or its hydrogenated block copolymer as a compatibilizer is disclosed in JP-A-58-213039 and JP-A-58-213039. 59-189147, JP-B-62-34782, JP-A-63-277253, JP-A-64-87645, JP-A-1-174550, JP-A-2-160855, JP-A-2-174550, JP-A-3-174550.
-157436 and the like. In addition, JP-A-4-
122751 describes that a mixture with a polyphenylene ether-based resin may be used as the polystyrene-based resin, but a specific example of blending the polyphenylene ether-based resin has not been carried out and its effect is not shown.

[0003]

However, in the styrene-conjugated diene block copolymer and the hydrogenated product of the styrene-conjugated diene block copolymer, the compatibilizing ability is insufficient, and thus it is necessary to blend a large amount thereof. is there. Therefore, the impact strength is improved, but the rigidity is hardly improved, which is not preferable in practical use.

[0004]

In order to solve the above-mentioned problems, the present inventors have studied various methods, and as a result, as a compatibilizer for polypropylene resin and polystyrene resin,
A block copolymer obtained by hydrogenating a double bond portion of a conjugated diene of an aromatic vinyl compound-conjugated diene compound block copolymer, which has a high ratio of the aromatic vinyl compound portion to the weight of the block copolymer. Using
By adding a small amount of polyphenylene ether resin, the compatibility of the hydrogenated block copolymer and polystyrene is improved, and the hydrogenated block copolymer is efficiently present at the interface between the polypropylene resin and the polystyrene resin. I succeeded in making it happen. By this, it is possible to reduce the amount of the hydrogenated block copolymer as a compatibilizer, and, as a result, the polypropylene resin, without impairing the original characteristics of the polystyrene resin, excellent mechanical properties It was found that they were expressed, and the present invention was achieved.

That is, the present invention comprises (a) polypropylene resin 95 to 51% by weight, (b) polystyrene resin 4.5 to 48.9% by weight, (c) polyphenylene ether resin 0.1 to 4% by weight. 9% by weight, (c) /
((B) + (c)) is 0.1 or less, (a) the polypropylene resin, (b) polystyrene resin,
(C) A conjugated diene compound polymer having at least one aromatic vinyl compound polymer block and at least one conjugated diene compound polymer block, based on 100 parts by weight of the polyphenylene ether resin. A block copolymer obtained by hydrogenating 70% or more of the double bond portion of the block is a polypropylene-based resin composition obtained by blending 1 to 40 parts by weight, and in the production of the above polypropylene-based resin composition, (B) Polystyrene resin and (c) Polyphenylene ether resin are separately melt-kneaded, and then all components are melt-kneaded, and the present invention relates to a method for producing a polypropylene resin composition.

The polypropylene resin used as the component (a) of the present invention is not particularly limited as long as it is a polymer obtained by polymerizing a propylene monomer as a main component.
A random or block copolymer with another α-olefin such as butene or 4-methylpentene-1, or a mixture thereof. Also, these are ethylene, 1
It may be a polypropylene-based copolymer composed of two or more of α-olefins such as butene and 4-methylpentene-1. Also, a mixture of these propylene-based resins may be used.

Of these, propylene homopolymer is particularly preferable. The crystallinity can be used without limitation, but one having a high crystallinity is preferable. Also,
Melt flow rate (MFR, ASTM D1238,
230 ° C, 2.16 kg load) is 0.01 to 100.0
g / 10 minutes is preferable, and MFR is more preferably 0.3 to 30.0 / 10 minutes. MFR is 0.01g
If it is less than / 10 minutes, melt-kneading and moldability are extremely difficult, and if it is more than 100.0 g / 10 minutes, the mechanical strength is insufficient.

The polystyrene resin used as the component (b) of the present invention includes styrene homopolymer (GPPS), rubber-modified high-impact polystyrene (HIPS), acrylonitrile-styrene copolymer (AS), and acrylonitrile-butadiene-styrene copolymer. Although it is a resin composed of a polymer (ABS), a methylmethacrylate-styrene copolymer, and a mixture thereof, GPPS and HIPS are preferable, and GPPS is particularly preferable. MFR (ASTM
D1238, 230 ° C, 2.16Kg load) is 0.0
1 to 100.0 g / 10 minutes is preferable, and MFR is more preferably 0.3 to 30.0 / 10 minutes. MFR
Is less than 0.01 g / 10 minutes, melt-kneading and moldability are extremely difficult, and above 100.0 g / 10 minutes, mechanical strength is insufficient.

Further, the ratio of MFR of the above-mentioned (a) polypropylene resin and (b) polystyrene resin (MFR of polypropylene resin / MFR of polystyrene resin).
Is preferably 0.2 to 5, more preferably 1 to 5, and particularly preferably 1 to 1.5. The polyphenylene ether resin (hereinafter simply abbreviated as PPE) used as the component (c) of the present invention has a bonding unit:

[0010]

[Chemical 1]

(Where R1, R2, R3, and R4
Are each selected from the group consisting of hydrogen, halogen, hydrocarbon, or substituted hydrocarbon, and may be the same or different from each other. ), And reduced viscosity (0.5 g / dl, chloroform solution, measured at 30 ° C.)
Is in the range of 0.15 to 0.70, more preferably 0.
It is a homopolymer and / or copolymer in the range of 02 to 0.60. Specific examples of the PPE include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), poly (2-methyl-). 6-phenyl-
1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether), and the like, and further, 2,6-dimethylphenol and other phenols (for example, 2,3,6-trimethyl). A copolymer with phenol or 2-methyl-6-butylphenol) is preferable, and among them, poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2,3,6-
A copolymer with trimethylphenol is preferable, and poly (2,6-dimethyl-1,4-phenylene ether) is particularly preferable.

The above-mentioned (a) polypropylene resin,
The blending ratio of (b) polystyrene-based resin and (c) PPE is such that (a) + (b) + (c) is 100% by weight and (a) is 95 to 51% by weight, preferably 90 to 55% by weight. , (B) is 4.5 to 48.9% by weight, preferably 9 to
39.9% by weight, and (c) is 0.1 to 4.9% by weight. If (a) the polypropylene resin is less than 51% by weight, the chemical resistance, solvent resistance and oil resistance which are the characteristics of the polypropylene resin are deteriorated, and if (a) the polypropylene resin exceeds 95% by weight, the polystyrene resin is The effect of improving the rigidity of the resin decreases. Also, (c) PPE is (c) /
((B) + (c)) is blended so as to be 0.1 or less,
It is preferably 0.03 to 0.06. Above 0.1, the rigidity decreases.

The hydrogenated block copolymer used as the component (d) of the present invention has at least one aromatic vinyl compound polymer block (A) and at least one conjugated diene polymer block (B). A block copolymer having the following structure, having a bound aromatic vinyl compound content of 15 to 85% by weight, and being hydrogenated with at least 70% of the double bonds of the conjugated diene moiety.

(AB) _n A- (BA) _n (n
Is an integer of 1 to 10) The aromatic vinyl compound polymer block (A) is styrene, α-methylstyrene, p-ethylstyrene, 2,4.
A polymer composed of dimethylstyrene, vinylnaphthalene, vinylanthracene or a mixture thereof, preferably a styrene homopolymer and α-methylstyrene, and particularly preferably a styrene homopolymer. The conjugated diene polymer block (B) is 1,3-butadiene, isoprene, 1,3-pentadiene, 3-butyl-1,3-
It is a polymer composed of octadiene, 4-ethyl-1,3-hexadiene or a mixture thereof, or a polymer composed of a mixture of the conjugated diene and an aromatic vinyl compound. Of these, 1,3-butadiene and isoprene are preferable.

When the conjugated diene polymer block (B) is 1,3-butadiene, hydrogenation will give 1,4 butadiene.
Ethylene is produced from the portion polymerized by the bond and butylene is produced from the portion polymerized by the 1,2 bond to form an ethylene / butylene copolymer (SEBS). There are no particular restrictions on the ethylene to butylene ratio of the ethylene / butylene copolymerization portion or the polymerization mode.

The number average molecular weight of the hydrogenated block copolymer is preferably 30,000 to 300,000, and particularly preferably 60,000 to 100,000. If the number average molecular weight is less than 30,000, the compatibilizing ability is lowered, and if it exceeds 300,000, melt-kneading is difficult. The proportion of the block (A) in the hydrogenated block copolymer is preferably 15 to 85% by weight, particularly preferably 50 to 70% by weight. If it is less than this range, the compatibilizing ability is insufficient, and if it is above this range, the impact strength is lowered.

The hydrogenation rate of the double bond portion of the block (B) of the hydrogenated block copolymer is preferably 70% or more, more preferably 90% or more. 7
If it is less than 0%, the compatibilizing ability is insufficient. The polypropylene resin composition of the present invention, if necessary, calcium carbonate, talc, glass fiber, glass beads, silica, whiskers, titanium oxide, aluminum hydroxide, ammonium hydroxide, inorganic fillers such as antimony oxide, carbon It may contain organic fillers such as black and carbon fibers, and optional additives such as antioxidants, pigments, flame retardants, antistatic agents, lubricants, and ultraviolet absorbers. The types of fillers and additives are not particularly limited as long as they are generally used in plastic compounding.

Further, a radical kneading agent such as an organic peroxide may be used for melt kneading for controlling the fluidity. The polypropylene-based resin composition of the present invention is obtained by melt-kneading the above-mentioned (a) polypropylene-based resin, (b) polystyrene-based resin, (c) PPE, and (d) hydrogenated block copolymer. In that case, (a) ~
Although the component (d) may be melt-kneaded at once, the component (c)
When melt-kneading is carried out under the temperature condition in which is sufficiently melted, heat deterioration of the resin other than the component (c) is likely to occur.

By the way, the component (b) and the component (c) are completely compatible, and when the amount of the component (c) is small, the composition obtained by melt-kneading the component (b) and the component (c) once. The product can be melt-kneaded at about the same temperature as polypropylene. Therefore, in order to obtain the composition of the present invention, a method of kneading the component (b) and the component (c) at a high temperature, blending the component (a) and the component (d) therein, and melt-kneading at a low temperature is preferable. For example, in the process of continuously manufacturing with an extruder,
(B) component and (c) component barrel temperature 260-320 ℃
Melt and knead with the barrel temperature from 180 to 250
It is possible to use a method of lowering the temperature to 0 ° C., adding the components (a) and (d) from that portion, and melt-kneading. Further, in the high temperature portion, 60 to 98% by weight of the component (b) and 40 to 2 of the component (c) are used.
You may melt-knead weight% and may add (a), (b), (d) component so that it may become a composition of this invention in a low temperature part.

Further, it is also possible to pre-knead the components (b) and (c) at a high temperature and then melt-knead the components (a) and (d) again at a low temperature. Preferably, (b) polystyrene resin (PS) 60 to 98% and (c) PPE4
Melt kneading 0-2% at 260-320 ℃, PS / PP
A masterbatch of E was prepared, and this was again added together with the components (a), (b) and (d) so that the composition ratio of the present invention was obtained.
This is a method of melt-kneading at 80 to 250 ° C.

[0021]

The present invention will be described in more detail by the following examples. However, the present invention is not limited to these examples. The following materials were used as the raw material resins of the examples and comparative examples. [1] Polypropylene resin (PP) PP-: Propylene homopolymer Melt flow rate (MFR) (230 ° C, 2.16 kg load) =
0.5 g / 10 min PP-: Propylene homopolymer MFR (230 ° C, 2.16 Kg load) = 2.0 g / 10 min [2] Polystyrene resin (PS) PS-: Styrene homopolymer MFR (230 ° C, 2.16Kg load) = 1.4g / 10min PS-: Styrene homopolymer Melt flow rate (MFR) (230 ° C, 2.16Kg load) =
1.6 g / 10 min [3] Polyphenylene ether-based resin (PPE) After the oxygen blowing part is at the bottom of the reactor and the inside of the stainless steel reactor having the cooling melt coil and the stirring blade inside is sufficiently replaced with nitrogen, Cupric bromide 53.6 g, di-n-butylamine 1110 g, further 20 liters of toluene,
8.75 kg of 2,6-xylenol was dissolved in a mixed solvent of 16 liters of n-butanol and 4 liters of methanol and charged into a reactor. Oxygen was continuously blown into the reactor while stirring to carry out polymerization for 180 minutes. In addition, in order to maintain the internal temperature at 30 ° C., water was circulated through the cooling coil during the polymerization. After the polymerization was completed, the precipitated polymer was filtered off, a methanol / hydrochloric acid mixture was added to decompose the residual catalyst in the polymer, and the polymer was thoroughly washed with methanol and dried to give a white powder PPE (reduction A viscosity of 0.54) was obtained. [4] Hydrogenated block copolymer (SEBS) A hydrogenated product of a styrene-butadiene tetrablock copolymer was used.

Number average molecular weight 85,000 Bound styrene amount 60% by weight Butylene amount 35% Hydrogenation rate 95%

[0023]

Examples 1 to 5 and Comparative Examples 1 and 5 PP, PS,
PPE and SEBS were blended in the composition shown in Table 1 and melt-kneaded together with a 25 mmφ co-rotating twin-screw extruder (ZSK-25; made by W & P) having a barrel temperature of 270 ° C., then water-cooled and cut. To obtain a pellet-shaped resin composition.

[0024]

[Comparative Examples 2 to 4] The above PP, PS and SEBS were blended in the composition shown in Table 1 and the barrel temperature was set to 230 ° C.
5mmφ co-rotating twin screw extruder (ZSK-25; W & P
Melt-kneading in batch, followed by cooling with water and cutting to obtain a pellet-shaped resin composition.

[0025]

Examples 6 to 8 and Comparative Example 6 PS / PPE = 60 /
A masterbatch was prepared by pre-kneading with a twin screw extruder having a composition ratio of 40 and a barrel temperature of 280 ° C. The masterbatch, PP, PS and SEBS were blended, and the barrel temperature was set to 230 ° C. A 25 mmφ co-rotating twin-screw extruder (ZSK-25; made by W & P) was melt-kneaded together, then cooled with water and cut to obtain a pellet-shaped resin composition.

Using these pellets, an injection molding machine (FA with a cylinder temperature of 230 ° C. and a mold temperature of 50 ° C.) was used.
S-50D; manufactured by FANUC) A test piece was molded. Also,
An ultrathin film was prepared from the pellets of Examples 1, 3, 4 and Comparative Examples 1 and 2 using an ultramicrotome and stained with ruthenium tetroxide vapor, followed by transmission electron microscopy (JEM).
-1200EXII; manufactured by JEOL Ltd.) and the following [8]
The morphology was observed by the method described in 1 above, and a photograph was taken to obtain a negative. Photos that stretched and printed them,
Shown as FIGS. In the figure, the continuous phase is polypropylene and the dispersed phase is a mixture of polystyrene and PPE.

Further, among the above photographs, four points except Comparative Example 1 were subjected to image analysis by the following method [9],
The equivalent circle diameter of the dispersed phase was determined and the particle size distribution was obtained. The results are shown in FIGS. The methods for measuring various physical properties used in the present invention are as follows. [1] Flexural Modulus (FM) ASTM D790 Autograph AG-5000D made by Shimadzu [2] Bending Strength (FS) ASTM D790 Autograph AG-5000D made by Shimadzu [3] Izod Impact Strength ASTM D256; 23 ° C Universal Impact Tester Toyo Seiki [4] Heat distortion temperature (HDT) ASTM D648; 4.6 Kg load Heat distortion tester No.148 HDA TYPE Yasuda Seiki [5] Melt flow rate (MFR) ASTM D1238; 230 ° C, 2.16 Kg load Melt Indexer TYPE C-5059D2 made by Toyo Seiki [6] Surface peeling test 100 pieces of 1 x 1 mm squares are attached to the surface of the injection molded plate of 148 x 148 x 2 mm using a razor, and cellophane tape (made by Nichiban) After attaching, peel off and attach to the surface of the molded piece. The number of remaining squares was counted. [7] Salad oil resistance test Dumbbell shaped molded pieces (ASTM Type 1) with a diameter of 1
Bend along a 7 cm cylinder, approximately 1c in the center of the test piece.
A gauze having a length of about 5 cm impregnated with Nissin salad oil of c was placed, and the state of crack generation was observed after 72 hours. [8] Photograph of transmission electron microscope photograph; JEM-1200EXII JEOL accelerating voltage; 100 KV beam current; 93 to 98 μA focusing lens diaphragm; minimum objective lens diaphragm; intermediate magnifying power; 5000 times exposure time; 1 second sample inclination; 0 ° [9] Measurement of particle size distribution Image analyzer: IP-1000 Image input device manufactured by Asahi Kasei; Color scanner JX-450 Sharp manufactured 11 × 11 Cm photograph stretched 20000 times,
Using an image input device, binarize the data read at a resolution of 200 dots / inch, separate it into a matrix and a domain, find the area of the domain from the number of dots it occupies, and find the equivalent circle diameter of that area. The value obtained by arithmetic averaging was used as the average particle size.

From these results, it was revealed that the polypropylene resin composition of the present invention is excellent in heat resistance, rigidity, impact resistance, oil resistance, and also in a dispersed state.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

EFFECT OF THE INVENTION The present invention is mainly composed of a polypropylene resin and a polystyrene resin, in which a specific block copolymer is blended as a compatibilizer, and a small amount of PPE is added.
A polypropylene resin composition having a high rigidity, excellent solvent resistance, oil resistance, chemical resistance, heat resistance, and particularly excellent impact resistance can be obtained.

[Brief description of drawings]

FIG. 1 is an electron micrograph showing the structure of particles of the composition of the present invention obtained in Example 1.

2 is an electron micrograph showing the structure of particles of the composition obtained in Example 3. FIG.

FIG. 3 is an electron micrograph showing the structure of particles of the composition obtained in Example 4.

FIG. 4 is an electron micrograph showing the structure of particles of the composition obtained in Comparative Example 1.

5 is an electron micrograph showing the structure of particles of the composition obtained in Comparative Example 2. FIG.

FIG. 6 is a graph showing the particle size distribution and average particle size (indicated by “Δ”) of the dispersed phase in the composition of the sample obtained in Example 1.

FIG. 7 is a graph showing the particle size distribution and average particle size (indicated by “Δ”) of the dispersed phase in the composition of the sample obtained in Example 3.

FIG. 8 is a graph showing the particle size distribution and average particle size (indicated by “Δ”) of the dispersed phase in the composition of the sample obtained in Example 4.

9 is a graph showing the particle size distribution and average particle size (indicated by “Δ”) of the dispersed phase in the composition of the sample obtained in Comparative Example 2. FIG.

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Claims (2)

[Claims] 1. (a) Polypropylene resin 95 to 51
% By weight, (b) polystyrene-based resin 4.5 to 48.9% by weight, (c) polyphenylene ether-based resin 0.1 to
4.9% by weight and (c) / ((b) +
(C)) is 0.1 or less, (d) aromatic based on 100 parts by weight of the total of the (a) polypropylene-based resin, (b) polystyrene-based resin, and (c) polyphenylene ether-based resin. A block copolymer having at least one vinyl compound polymer block and at least one conjugated diene compound polymer block, and obtained by hydrogenating 70% or more of the double bond portion of the conjugated diene compound polymer block. 1 to 40 parts by weight of a polypropylene resin composition. 2. In the production of the polypropylene resin composition according to claim 1, (b) a polystyrene resin,
(C) A method for producing a polypropylene resin composition, which comprises melt-kneading a polyphenylene ether-based resin separately and then melt-kneading all components.