JPH11279340A - Large-sized blow molding polyolefinic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a large-sized blow molding polyolefinic resin composition which has a high melt strength, allows little drawdown of parison when blow- molded, has a good appearance and has a uniform thickness in section. SOLUTION: The composition comprises, against 100 pts.wt. polyolefinic resin (A) having a melt flow rate(MFR) from 0.1 to 7 g/ 10 min, a polytetrafluoroethylene-containing mixed powder (B) comprising a polytetrafluoroethylene particle with a particle size of 10 μm or smaller, and an organic polymer at an amount which gives an amount of the polytetrafluoroethylene content of from 0.01 to 20 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to conventional containers and cans using polyolefins, as well as non-container fields developed with recent advances in blow molding technology, such as automobile parts such as bumpers, OA equipment, The present invention relates to a polyolefin-based resin composition for large blows of home appliances and furniture.

[0002]

2. Description of the Related Art Conventionally, in the field of blow molded articles, high density polyethylene (HDPE), polypropylene (P
Polyolefin-based resins such as P), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE) have been used in containers such as bottles and cans, as well as in non-container fields such as furniture and home appliances. However, these resins are inherently insufficient in melt strength at the time of molding because they are crystalline, and the parison draws down, resulting in uneven wall thickness and is not suitable for molding large molded articles.

[0003] In order to increase the melt strength, large-sized molded products have been made of high molecular weight resin or partially crosslinked resin. However, the flowability is reduced in contrast to the melt strength. The appearance of the molded product is impaired, and if the molding temperature is increased to increase the fluidity, the thermal decomposition of the resin proceeds,
It has been difficult to obtain a large-sized blow molded article of a polyolefin-based resin excellent in appearance with little uneven thickness, such as a decrease in molecular weight and drawdown of parison.

For example, Japanese Patent Application Laid-Open No. 05-185490 discloses a polyolefin copolymer containing a monomer having a polyene as a constituent component, but it is difficult to control the polyolefin copolymer because it involves a crosslinking reaction. JP-A-07-316361, JP-A-08-802381, JP-A-09-3
No. 1268 discloses a method in which a low melt flow rate (MFR) polyolefin resin and an inorganic filler are combined, and JP-A-09-328587 discloses two kinds of high molecular weight ethylene-propylene copolymers in polypropylene,
LDPE and a method of adding an inorganic filler are disclosed, but in these methods, when blow molding a polyolefin-based resin, the drawdown of a target parison is small, the uneven thickness is small, and the appearance is excellent. It is difficult to efficiently obtain a large molded product, and in reality, satisfactory products have not been obtained.

[0005] On the other hand, polytetrafluoroethylene has a property of forming fibers with a slight stress, and it is known that when it is blended with a thermoplastic resin, the formability and mechanical properties are improved. I have. For example, Japanese Patent Application Laid-Open No. 5-214
184 and JP-A-6-306212 disclose resin compositions in which polytetrafluoroethylene is mixed with polyolefin. Also, JP-A-8-1
No. 65358 discloses a thermoforming polyolefin sheet containing fibrous polytetrafluoroethylene with respect to polyolefin. However, polytetrafluoroethylene generally has poor dispersibility in a polyolefin resin, and it is difficult to uniformly disperse it with a simple blend as described in JP-A-5-214184 and JP-A-6-306212. And products with excellent appearance cannot be obtained. Also, JP-A-8-16535
No. 8, it is difficult to convert all polytetrafluoroethylene into fibers by shearing force. That is, all of these methods have a problem in the dispersibility of porotetrafluoroethylene, and it has been difficult to obtain a polyolefin-based blow-molded article having excellent appearance.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a large blow-molded polyolefin resin composition having excellent melt strength, reduced parison drawdown during blow molding, excellent appearance, and reduced uneven wall thickness. Is to do.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a small amount of polytetrafluoroethylene comprising polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer. By adding the contained mixed powder to a polyolefin resin having a limited MFR, a resin composition is obtained in which a drawdown at the time of blow molding is small and a large polyolefin-based blow molded product having a good product appearance is obtained. The present invention has been reached.

[0008] That is, the gist of the present invention is that the MFR is 0.
Polyolefin resin (A) 100 for 1 to 7 g / 10 minutes
The polytetrafluoroethylene-containing mixed powder (B) composed of polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer is contained in an amount of 0.01 to 20 parts by weight with respect to parts by weight. And a polytetrafluoroethylene-containing mixed powder (B) composed of polytetrafluoroethylene particles having an average particle diameter of 10 μm or less and an organic polymer, and a portion thereof. The master pellet made of the polyolefin resin (A) is obtained by adding 0.01 to 20 parts by weight of the remaining polyolefin resin (A) to the polytetrafluoroethylene component based on 100 parts by weight of the total amount of the polyolefin resin (A). The polyolefin-based resin composition for large-size blow molding compounded so that

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyolefin resin (A) used in the present invention is a component used as a base resin in the resin composition of the present invention.
P), high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LL
DPE), poly-1-butene, polyisobutylene, random or block copolymers in any ratio of propylene to ethylene and / or 1-butene;
Cyclic diolefins such as ethylene-propylene-diene terpolymers, polymethylpentene, copolymers of cyclopentadiene with ethylene and / or propylene, wherein the diene component is 50% by weight or less in any ratio of ethylene and propylene; Random copolymers, block copolymers or graft copolymers of ethylene or propylene with not more than 50% by weight of vinyl compounds such as vinyl acetate, alkyl methacrylate, acrylate, aromatic alkyl ester and aromatic vinyl These can be used alone or in combination of two or more.

In the present invention, the polyolefin resin (A) includes PP, HDPE, LDPE, LLD
PE, at least one selected from ethylene-propylene random or block copolymer has high versatility,
It is preferable in that it is inexpensive.

The MFR of the polyolefin resin (A) used in the present invention is preferably 0.1 to 7 g / 10 min, more preferably 0.3 to 3 g / 10 min.
When the polytetrafluoroethylene-containing mixed powder (B) is blended, it is preferable from the viewpoint of obtaining a large molded product having a small parison during blow molding and having excellent appearance. MFR of polyolefin resin (A) is 0.1 g /
If the time is less than 10 minutes, the fluidity is not sufficient, and the gloss of the molded product,
When the MFR exceeds 7 g / 10 minutes, the drawdown of the parison becomes large and it becomes difficult to obtain a large molded product. The MFR is ASTM D
It is measured under a load of 2.16 kg according to 1238. For example, 230 ° C. for propylene-based polyolefin
In the case of ethylene-based polyolefin.
The value at 0 ° C.

The polytetrafluoroethylene-containing mixed powder (B) used in the present invention comprises polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer, and the polytetrafluoroethylene in the powder has a particle diameter of 10 μm or more. It is necessary that they are not aggregated. As such a polytetrafluoroethylene-containing mixed powder, an aqueous dispersion of polytetrafluoroethylene particles having a particle diameter of 0.05 to 1 μm and an aqueous dispersion of organic polymer particles are mixed,
After polymerization of the monomer constituting the organic polymer in the presence of an aqueous dispersion of polytetrafluoroethylene particles having a particle size of 0.05 to 1 μm, Or those obtained by pulverization by spray drying, or particles having a particle size of 0.1.
A monomer having an ethylenically unsaturated bond is emulsion-polymerized in a dispersion obtained by mixing an aqueous dispersion of polytetrafluoroethylene particles of 0.5 to 1 μm and an aqueous dispersion of organic polymer particles, and then coagulated or sprayed. Those obtained by pulverization by drying are preferred.

Commercially available raw materials for the polytetrafluoroethylene particle dispersion include Fluon AD-1 and AD-936 manufactured by Asahi ICI Fluoropolymer Co., Ltd., and Polyflon D-1 and D-2 manufactured by Daikin Industries, and Mitsui Dupont Fluoro. A typical example is Teflon 30J manufactured by Chemical Company.

The organic polymer constituting the polytetrafluoroethylene-containing mixed powder (B) used in the present invention includes:
Although not particularly limited, those having high compatibility with the olefin resin are preferred from the viewpoint of dispersibility when blended into the polyolefin resin (A).

Specific examples of the monomer for forming the organic polymer include styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, o-methoxystyrene. Styrene, α
-Styrene-based monomers such as methylstyrene: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid-
(Meth) acrylate monomers such as 2-ethylhexyl, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate: acrylonitrile, Vinyl cyanide monomers such as methacrylonitrile: vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether: vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate; ethylene, propylene, isobutylene, etc. Olefin-based monomers: Diene-based monomers such as butadiene and isoprene can be exemplified. These monomers can be used alone or in combination of two or more.

Among these monomers, styrene-based monomers, (meth) acrylate-based monomers, and olefin-based monomers are preferable in terms of compatibility with the polyolefin-based resin (A). The body can be mentioned. Preferably, at least 20% by weight of one or more monomers selected from the group consisting of long-chain alkyl (meth) acrylate monomers having 5 to 30 carbon atoms, styrene, and olefin monomers. The contained monomer can be mentioned. In particular, a long-chain alkyl (meth) acrylate monomer having 12 to 30 carbon atoms is preferable.

The content of polytetrafluoroethylene in the polytetrafluoroethylene-containing mixed powder (B) used in the present invention is preferably 0.1 to 90% by weight.

The polytetrafluoroethylene-containing mixed powder (B) used in the present invention is poured into hot water in which a metal salt such as calcium chloride or magnesium sulfate is dissolved, and then salted out. Dry after solidifying, or
It can be pulverized by spray drying.

Normal polytetrafluoroethylene fine powder forms aggregates of 100 μm or more in the step of recovering the powder from the state of the particle dispersion, so that it is difficult to uniformly disperse it in the thermoplastic resin. On the other hand, since the polytetrafluoroethylene-containing mixed powder (B) used in the present invention does not independently form a domain having a particle diameter of more than 10 μm, the polytetrafluoroethylene-based mixed powder (B) is based on the polyolefin resin (A). Excellent dispersibility. As a result, in the resin composition of the present invention, polytetrafluoroethylene is efficiently fiberized in the polyolefin-based resin (A), the draw-down of the parison is small, the appearance is excellent, and a large blow molded product without uneven thickness is obtained. can get.

The resin composition used in the present invention is obtained by mixing the polytetrafluoroethylene-containing mixed powder (B) with the polyolefin resin (A) having an MFR in the range of 0.1 to 7 g / 10 minutes. It is blended so that the amount of the tetrafluoroethylene component is 0.01 to 20 parts by weight. If the amount of the polytetrafluoroethylene component (B) is less than 0.01 part by weight, the drawdown of the parison cannot be suppressed, and if it exceeds 20 parts by weight, the fluidity becomes insufficient and the large blow molding having excellent appearance is obtained. Goods are not obtained.

[0021] Additives such as stabilizers, lubricants and inorganic fillers can be added to the resin composition of the present invention, if necessary.

Examples of the stabilizer include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and triethylene glycol-bis [3- (3-t-butyl-5). -Methyl-4-hydroxyphenyl) propionate], phosphorus stabilizers such as tris (monononylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, dilauroyl Examples thereof include sulfur-based stabilizers such as dipropionate, and these can be used alone or in combination of two or more. The compounding amount of such a stabilizer is polyolefin resin (A) 10
0.05 parts by weight or less with respect to 0 parts by weight is preferred.

Representative examples of the lubricant include sodium, calcium and magnesium salts of saturated or unsaturated fatty acids such as lauric acid, palmitic acid, oleic acid and stearic acid. These may be used alone or in combination of two or more. These can be used in combination. The amount of the lubricant is preferably 0.1 to 2 parts by weight based on 100 parts by weight of the polyolefin resin (A).

Representative examples of the inorganic filler include, for example, calcium carbonate, talc, glass fiber, magnesium carbonate, mica, kaolin, calcium sulfate, aluminum hydroxide, magnesium hydroxide, silica, clay, zeolite and the like. These can be used alone or in combination of two or more. The amount of the inorganic filler is preferably 1 to 50 parts by weight based on 100 parts by weight of the polyolefin resin (A).

The above-mentioned essential components and optional components are blended in predetermined amounts, and the resin composition is adjusted using a usual kneading machine such as a roll, a Banbury mixer, an extruder, etc. Usually, the resin composition is formed into pellets. Is preferred. Further, a master pellet (master batch) containing the polytetrafluoroethylene-containing mixed powder (B) at a high concentration may be diluted with the polyolefin-based resin (A) to form a resin composition. At this time, the amount of polytetrafluoroethylene was 0.01 to 100 parts by weight of the total amount of the polyolefin resin (A).
It is preferred to be blended so as to be 20 parts by weight. Further, the polyolefin resin (A) to be diluted and the remaining polyolefin resin (A) may not be the same.

A molded article is obtained from the composition by using a blow molding machine, but the shape of the molded article is not limited, and a bottle, a can, a hollow plate, a tube, or the like can be obtained. .

[0027]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" indicates parts by weight, "%" indicates weight%, and various physical properties were measured by the following methods.

(1) Solid content concentration: 170 ° C. of the particle dispersion
And dried for 30 minutes.

(2) Particle size distribution, weight average particle size: A solution obtained by diluting a particle dispersion with water was used as a sample solution, and a dynamic light scattering method (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature: 25 ° C., scattering angle: 90) Degree).

(3) MFR: A load of 2.16 kg according to ASTM D1238, 230 ° C. for propylene-based polyolefin and 190 ° C. for ethylene-based polyolefin
Was measured.

(4) Drawdown characteristics of parison: The parison is extruded using a blow molding machine, and when the tip of the parison reaches 1 m from the die, the parison is cut just below the die and the weight of the parison is measured. This value is small for materials that have a large drawdown and are not suitable for large-size molding,
Under the following conditions, a barison weight of 250 g or more is a guide for forming a large blow molded product having a parison length of at least 100 cm without uneven thickness.

(Blow molding machine: manufactured by Tahara Seisakusho, screw diameter: -50 mmφ, single shaft, rotation speed: -50 rpm, barrel temperature: −200 ° C., parison outer diameter at the tip of the die: −60 mm,
(Inner diameter -57 mm) (5) Appearance of molded article: The surface state and gloss of the parison are visually judged. ：: The surface is smooth and glossy. X: The surface is rough and glossless.

Reference Example 1 <Production of polytetrafluoroethylene-containing mixed powder (B-1)> In a separable flask equipped with a stirrer, a condenser, a thermocouple, and a nitrogen inlet, 190 parts of distilled water and dodecylbenzenesulfonic acid were added. 1.5 parts of sodium, 100 parts of styrene and 0.5 part of cumene hydroperoxide were charged and heated to 40 ° C. under a nitrogen stream. Next, a mixed solution of 0.001 part of iron sulfate, 0.003 part of disodium ethylenediaminetetraacetate, 0.24 part of Rongalite salt, and 10 parts of distilled water was added to carry out radical polymerization. After the end of the exotherm, raise the temperature in the system to 4
The polymerization was completed by holding at 0 ° C. for 1 hour to obtain a styrene polymer particle dispersion (hereinafter referred to as P-1).

The solid content concentration of P-1 was 33.3%, the particle size distribution showed a single peak, and the weight average particle size was 96 n.
m.

On the other hand, as a polytetrafluoroethylene-based particle dispersion, Fluon AD manufactured by Asahi ICI Fluoropolymer Co., Ltd.
936 was used. AD936 has a solid content of 63.0%
And containing 5 parts of polyoxyethylene alkylphenyl ether per 100 parts of polytetrafluoroethylene. The particle size distribution of AD936 showed a single peak, and the weight average particle size was 290 nm.

To 833 parts of AD936, 1167 parts of distilled water was added to obtain a polytetrafluoroethylene particle dispersion F-1 having a solid content of 26.2%. F-1 contains 25% of polytetrafluoroethylene particles and 1.2% of polyoxyethylene nonylphenyl ether.

A separable flask equipped with a stirrer, a condenser, a thermocouple, and a nitrogen inlet was prepared by mixing 160 parts of F-1 (40 parts of polytetrafluoroethylene) and 181.8 parts of P-1 (60 parts of polystyrene). And stirred at room temperature for 1 hour under a nitrogen stream. Thereafter, the inside of the system was heated to 80 ° C. and kept for 1 hour. No solid matter was separated through a series of operations, and a uniform particle dispersion was obtained. The solid content concentration of the particle dispersion was 29.3%, the particle size distribution was relatively broad, and the weight average particle size was 168 nm.

341.8 parts of this particle dispersion was poured into 700 parts of 85 ° C. hot water containing 5 parts of calcium chloride, the solid content was separated, filtered and dried to obtain a mixed powder of polytetrafluoroethylene (B -1) 98 parts were obtained.

After B-1 was shaped into a strip at 250 ° C. by a press molding machine, ultrathin sections were observed with a microtome and observed with a transmission electron microscope without staining. Although polytetrafluoroethylene is observed as a dark area, 10 μm
No aggregates exceeding m were observed.

REFERENCE EXAMPLE 2 <Production of polytetrafluoroethylene-containing mixed powder (B-2)> A mixture of 75 parts of dodecyl methacrylate and 25 parts of methyl methacrylate was added with azobisdimethylvaleronitrile 0.1%.
One part was dissolved. A mixed solution of 2.0 parts of sodium dosylbenzenesulfonate and 300 parts of distilled water was added thereto,
After stirring at 10,000 rpm for 4 minutes with a homomixer, the mixture was passed through a homogenizer twice at a pressure of 300 kg / cm ² to obtain a stable dodecyl methacrylate / methyl methacrylate preliminary dispersion. This was charged into a separable flask equipped with a stirrer, a condenser, a thermocouple, and a nitrogen inlet, and stirred at 80 ° C. for 3 hours under a nitrogen stream to carry out radical polymerization, so that dodecyl methacrylate / methyl methacrylate was added. A polymer particle dispersion (hereinafter referred to as P-2) was obtained.

The solid concentration of P-2 was 25.1%, the particle size distribution showed a single peak, and the weight average particle size was 198.
nm.

160 parts (40 parts of polytetrafluoroethylene) of F-1 used in Reference Example 1 and 159.4 parts of P-
2 (40 parts of dodecyl methacrylate / methyl methacrylate copolymer) was charged into a separable flask equipped with a stirrer, a condenser, a thermocouple, a nitrogen inlet, and a dropping funnel, and stirred at room temperature for 1 hour under a nitrogen stream. Thereafter, the temperature inside the system was raised to 80 ° C., and 0.001 part of iron sulfate, 0.003 part of disodium ethylenediaminetetraacetate, and Rongalit salt 0.1% were added. After adding a mixture of 24 parts and 10 parts of distilled water, a mixture of 20 parts of methyl methacrylate and 0.1 part of tertiary butyl peroxide was added dropwise over 30 minutes. It was kept for 1 hour to complete the radical polymerization. No solid content was separated through a series of operations, and a uniform particle dispersion was obtained. The solid content concentration of the particle dispersion was 28.5%, the particle size distribution was relatively broad, and the weight average particle size was 248 nm.

349.7 parts of this particle dispersion was poured into 600 parts of 75 ° C. hot water containing 5 parts of calcium chloride, the solid content was separated, filtered, and dried to obtain a mixed powder of polytetrafluoroethylene (B). -2) 97 parts were obtained.

The dried B-2 was shaped into strips at 220 ° C. by a press molding machine, and ultrathin sections were observed with a microtome without staining using a transmission electron microscope.
Although polytetrafluoroethylene was observed as a dark part, no aggregate exceeding 10 μm was observed.

Reference Example 3 <Production of master batch (M-1) of mixed powder containing polytetrafluoroethylene> 75 parts of linear homopolypropylene pellets (EA7, manufactured by Nippon Polychem Co., Ltd., MFR 1.2 g / 10 min) And the mixed powder B-2 containing tetrafluoroethylene obtained in Reference Example 2
Were blended and hand-blended, and then twin-screw extruder (ZSK3 manufactured by Werner & Pfleiderer)
Using 0), the mixture was melt-kneaded at a barrel temperature of 200 ° C. and a screw rotation speed of 200 rpm, and shaped into pellets to obtain a master batch (hereinafter referred to as M-1) of a mixed powder containing polytetrafluoroethylene. .

Examples 1-6, Comparative Examples 1-3 The following linear homopolypropylene pellets, tetrafluoroethylene-containing mixed powders obtained in Reference Examples (B-1 and 2)
Alternatively, the master pellet (M-1) was blended in the ratio shown in Table 1, and a parison for a large molded product was extruded using the blow molding machine under the above-described conditions, and the appearance was observed and the drawdown characteristics were evaluated. The measurement was performed and the results are shown in Table 1.

Polypropylene “Novatech PP” manufactured by Nippon Polychem Co., Ltd. FY6: MFR 2.5 EA9: MFR 0.5

[0048]

[Table 1]

The following polyethylene, the mixed powder containing tetrafluoroethylene (B-1 to 2) obtained in the reference example, or the master batch pellet (M-1) was blended in the ratio shown in Table 2, and the above blow molding machine was used. And blow molding was performed in the same manner as in Examples 1 to 6, and the obtained results are shown in Table 2.

Polyethylene HIZEX 3000B (HDPE) manufactured by Diapolymer Co., Ltd .: MFR 0.6 Mirason 50 (LDPE): MFR 1.9 ULTOZEX 1520L (LLDPE): MFR 2.3

[0051]

[Table 2]

Examples 15 to 21 Using the above-mentioned twin-screw extruder, a barrel temperature of 200 ° C. and a screw rotation speed of 2 were used for the above-mentioned composition using a combination of polypropylene and polyethylene and talc as a filler.
Table 3 shows the results obtained by shaping at 00 rpm and molding in the same manner as in Examples 1 to 14.

[0053]

[Table 3]

[0054]

According to the present invention, there is provided a polyolefin-based resin composition which has a small drawdown of an extruded parison during blow molding, and as a result, enables a large blow-molded article having excellent appearance without uneven thickness. Molded articles obtained from the resin composition of the present invention are used for automobile parts such as bumpers, OA equipment, home appliances, furniture and the like, in addition to conventional bottles and cans.

Claims (5)

[Claims] 1. A melt flow rate of 0.1 to 7 g / 1
A polytetrafluoroethylene-containing mixed powder (B) composed of polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer is mixed with 100 parts by weight of the polyolefin resin (A), which is 0 minutes, to obtain polytetrafluoroethylene. A large-sized blow-molding polyolefin-based resin composition blended so that the amount of the ethylene component is 0.01 to 20 parts by weight. 2. A master pellet composed of a polytetrafluoroethylene-containing mixed powder (B) having a particle diameter of 10 μm or less and a part of a polyolefin resin (A) is used as a total amount of the remaining polyolefin resin (A) of 100 weight. For the department
The amount of the polytetrafluoroethylene component is 0.01 to 20
A polyolefin-based resin composition for large blow molding comprising a resin composition blended to be in parts by weight. 3. A polytetrafluoroethylene-containing mixed powder (B) is obtained by mixing an aqueous dispersion of polytetrafluoroethylene particles and an aqueous dispersion of organic polymer particles and pulverizing them by coagulation or spray drying. The polyolefin resin composition for large blow molding according to claim 1, which is obtained. 4. The polytetrafluoroethylene-containing mixed powder (B) is obtained by polymerizing monomers constituting an organic polymer in the presence of an aqueous dispersion of polytetrafluoroethylene particles, followed by coagulation or spray drying. The polyolefin resin composition for large blow molding according to claim 1, which is obtained by pulverization. 5. The polytetrafluoroethylene-containing mixed powder (B) is mixed with an aqueous dispersion of polytetrafluoroethylene particles and an aqueous dispersion of organic polymer particles to form an ethylenically unsaturated bond. The polyolefin resin composition for large blow molding according to claim 1, which is obtained by emulsion polymerization of a monomer having the following, followed by coagulation or spray drying to obtain a powder.