JP5050486B2 - Granules and method for producing the same - Google Patents

Description

  The present invention relates to a group of granules suitable as a plastic additive such as polyolefin.

It is known that a phenolic antioxidant significantly reduces oxidative deterioration caused by light or heat in a polyolefin molded body when added to polyolefin such as polyethylene and polypropylene.
The phenolic antioxidant is usually a powder having a melting point of about 100 ° C. and a median diameter of 5 to 70 μm, and does not melt and is added to the polyolefin with good fluidity from a hobber or the like. Because of the dust generated from this powder, it was necessary to take measures to prevent dust when added to polyolefin.
Under such circumstances, antacid addition such as tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane and stearate, which is one of phenolic antioxidants, is added. After mixing with the agent, heat to 115 ° C to dissolve part of the phenolic antioxidant, and then mix the phenolic antioxidant and antacid additive in the form of 2.5 mm pellets with an extruder Patent Document 1 discloses a method for producing pellets. It is disclosed that the pellets are dust-free even when no binder is used, which is undesirable for polyolefins such as paraffin, and that there is no problem when added to polyolefins.
However, polyolefins obtained by melt-kneading pellets obtained by applying heat of 100 ° C. or higher to phenolic antioxidants in advance have a problem that thermal stability varies, and they are extruded using an expensive extruder. There was also a problem that it had to be molded.

Japanese Patent Laid-Open No. 5-179056 (for example, Example 1)

As a result of investigations by the present inventors, it has been found that a polyolefin obtained by melt-kneading pellets obtained by previously applying a heat of 100 ° C. or more to a phenolic antioxidant has a variation in thermal stability. Further, the method of Patent Document 1 has a problem that it must be extruded using an expensive extruder.
The object of the present invention is to have excellent fluidity when additives such as antioxidants are added to plastics such as polyolefins, hardly generate dust from additives, and can be manufactured with simple equipment. In addition, the thermal stability of the obtained plastic is to provide an additive mainly composed of an antioxidant and a method for producing the same, which hardly vary.

That is, this invention is a granule group which consists of a granule containing the phenolic antioxidant shown by Formula (1), and the sulfur type antioxidant shown by Formula (2), Comprising: A phenolic antioxidant (1) And a group of granules in which the content of the sulfur-based antioxidant (2) is 3 to 70 parts by weight with respect to a total of 100 parts by weight of the sulfur-based antioxidant (2), and the sulfur-based antioxidant represented by the formula (2) It is the manufacturing method of the granule group which stirs and granulates 100 weight part of mixtures which contain 3-70 weight part of agents and the phenolic antioxidant shown by Formula (1) in the temperature range of 40-70 degreeC.

[In Formula (1), R ₁ represents an alkyl group having 1 to 8 carbon atoms, and X represents an n-valent alcohol residue having 1 to 18 carbon atoms which may include a hetero atom and / or a cyclic group. , N represents an integer of 1 to 4. ]

_{(R 2 -Y-S-C} 2 H 4 CO 2) m -Z (2)
[In Formula (2), R ₂ represents an alkyl group having 12 to 18 carbon atoms, Y represents a single bond or a —C ₂ H ₄ CO ₂ — group, and Z represents an m-valent alcohol having 5 to 18 carbon atoms. Represents a residue, and m represents an integer of 1 to 4. ]

Furthermore, the present invention provides a plastic composition obtained by blending 0.005 to 5 parts by weight of the granules with respect to 100 parts by weight of the plastic, and 0.005 of the granules per 100 parts by weight of the plastic. A method of stabilizing a plastic compounded with ˜5 parts by weight.

  The granule group of the present invention hardly generates dust and has excellent fluidity, and the plastic obtained by melt-kneading the granule group of the present invention has excellent thermal stability, and its thermal stability is less likely to vary. . Moreover, according to the method for producing a granule group of the present invention, the granule group can be produced with simple equipment.

Hereinafter, the present invention will be described in detail.
The phenolic antioxidant used in the present invention is a compound represented by the formula (1).
As R ₁ in the phenolic antioxidant (1), a methyl group, a t-butyl group, a t-pentyl group, a t-octyl group, and the like are preferable, and a methyl group and a t-butyl group are particularly preferable.

X in the phenolic antioxidant (1) represents an n-valent alcohol residue having 1 to 18 carbon atoms, and the alcohol residue means a group in which a hydrogen atom is eliminated from a hydroxyl group of alcohol.
X in the phenolic antioxidant (1) is a residue of triethylene glycol, a residue of pentaerythritol, or 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8. , 10-tetraoxaspiro [5,5] undecane residues, etc. are preferred, especially the residue of pentaerythritol, or 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8. , 10-tetraoxaspiro [5 · 5] undecane residues are preferred. N in the phenolic antioxidant (1) is preferably 2 or 4.

Melting | fusing point of a phenolic antioxidant (1) is about 70-220 degreeC normally, Preferably, it is 70-150 degreeC, More preferably, it is 100-130 degreeC.
When the melting point of the above-mentioned phenolic antioxidant (1) is 220 ° C. or lower, the dispersibility to plastic tends to be improved. This is preferable because of the tendency to

  Examples of the phenol-based antioxidant (1) include 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl. ] -2,4,8,10-tetraoxaspiro [5.5] undecane, bis {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionic acid} triethyleneglycolyl ester, tetrakis And {3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionic acid} pentaerythrityl ester.

The weight-based median diameter of the phenolic antioxidant (1) is usually about 1 to 100 μm, preferably about 5 to 70 μm. If the median diameter of the phenolic antioxidant is 1 μm or more, the production time of the granules tends to be shortened or the heating temperature tends to be reduced, whereas if it is 100 μm or less, granulation does not occur. Often exhibits a high liquidity index.
The fluidity index in the present invention is a Carr's fluidity index, and four types of values of repose angle, compression degree, spatula angle, and uniformity or agglomeration degree of a granule group are measured. The maximum index of 25 found empirically in the powders and grains is assigned, and the total index (the maximum value is 100 and the minimum value is 0) is indicated [Edited by Powder Technology Society, “Powder Physical Engineering Glossary ", 2nd edition, Nikkan Kogyo Shimbun, March 30, 2000, p. 56-p. 57].

The sulfur-based antioxidant used in the present invention is a compound represented by the formula (2).
In the sulfur-based antioxidant (2), R ₂ is preferably a dodecyl group, a tetradecyl group or an octadecyl group. As m, 1 or 4 is preferable.
Z in the sulfur-based antioxidant (2) represents an m-valent alcohol residue having 5 to 18 carbon atoms, and the alcohol residue means a group in which a hydrogen atom is eliminated from a hydroxyl group of the alcohol. Z is preferably a residue of dodecyl alcohol, a residue of tetradecyl alcohol, a residue of octadecyl alcohol or a residue of pentaerythritol. In particular, when Y in the sulfur-based antioxidant (2) is a single bond, a compound in which R ₂ is a dodecyl group, m is 4, and Z is a pentaerythritol residue is preferable. Further, Y is _{-C 2 H} 4 CO 2 - is a group is, _{R 2} is a dodecyl group, a tetradecyl group or an octadecyl group, m is 1, the number of carbon atoms Z corresponds to the _{R 2.} 12 to 18 alcohol residues are preferred.

Specific examples of the sulfur-based antioxidant that can be used in the present invention include the following compounds.
3,3′-thiodipropionic acid di-n-dodecyl ester,
3,3′-thiodipropionic acid di-n-tetradecyl ester,
3,3′-thiodipropionic acid di-n-octadecyl ester,
Among tetrakis (3-dodecylthiopropionic acid) pentaerythrityl ester, 3,3′-thiodipropionic acid di-n-dodecyl ester, 3,3′-thiodipropionic acid di-n-tetradecyl ester, 3,3 '-Thiodipropionic acid di-n-octadecyl ester is preferred.

In the granule group of the present invention, the content of the sulfur-based antioxidant (2) with respect to 100 parts by weight in total of the phenol-based antioxidant (1) and the sulfur-based antioxidant (2) is preferably 3 to 70 parts by weight. Is 8 to 35 parts by weight. It is preferable for the content of the sulfur-based antioxidant (2) to be 3 parts by weight or more because there is a tendency to shorten the granule production time, reduce the heating temperature, and improve the fluidity index. When it is 70 parts by weight or less, it is preferable because it tends to suppress the formation of coarse granules, and when it is 35 parts by weight or less, it tends to suppress the formation of coarse granules and the size of the granules can be easily controlled. Is particularly preferred.
In the case where the granule group of the present invention contains an additive to be described later, when 8 parts by weight or more of the sulfur-based antioxidant (2) is mixed with 100 parts by weight of the granule group, the granule production time is shortened or heated. This is particularly preferred because the temperature tends to be reduced.
Moreover, in the granule group of this invention, content of the phenolic antioxidant (1) with respect to a total of 100 weight part of a phenolic antioxidant (1) and a sulfur type antioxidant (2) is 97-3 normally. Parts by weight.

In the present invention, each granule does not mean that the phenolic antioxidant (1) and the sulfurous antioxidant (2) are contained in the above-mentioned weight ratio, but the whole granule. It means that the granule group which means is comprised including the phenolic antioxidant (1) and the sulfurous antioxidant (2) in the said weight ratio.
Moreover, the granule group of this invention means the granule aggregate of the irregular shape as described in JIS-Z 8841 (1993) 10th description table 1 shape and name of granulated material.

The granule group of the present invention may further contain at least one additive selected from the following additive group as long as the granule characteristics (granulation operability) are not affected. Usually, the total content of the additives in the granule group is about 0 to 90% by weight. As the additive, an organic additive or an inorganic additive having a melting point of 70 ° C. or higher is preferable from the viewpoint of granule characteristics.
In addition, the weight-based median diameter of the additive used in the present invention is preferably in the range of 0.1 to 100 μm, and particularly preferably in the range of 0.5 to 70 μm.
When using a commercially available additive as it is, it is preferable to use it after adjusting to the median diameter of a weight basis preferable with a well-known method beforehand.
[Additives group: neutralizer, lubricant, phosphorus antioxidant, hindered amine light stabilizer, ultraviolet absorber, metal soap, antistatic agent, anti-blocking agent, pigment, flame retardant, filler, and phenolic Phenolic antioxidants other than antioxidant (1)]

Examples of the additive include the following compounds.
Synthetic hydrotalcite, natural hydrotalcite, neutralizing agents such as calcium hydroxide; lubricants such as oleic acid amide, erucic acid amide, polyethylene wax;

  Tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) Pentaerythritol diphosphite, bis (2,4-di-cumylphenyl) pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene diphosphonite, 6- [3- (3-t- [Butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10-tetra-t-butyldibenz [d, f] [1,3,2] dioxaphosphine Agent;

  Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3, -tetramethylbutyl) amino-1,3,5-triazine-2, 4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} -1,6-hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] Hindered amine light stabilizers such as

  2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butylphenyl UV absorbers such as 3,5-di-t-butyl-4-hydroxybenzoate;

  Fillers such as calcium carbonate, silicate, glass fiber, talc, kaolin, mica, barium sulfate, carbon black, carbon fiber, zeolite, metal powder, metal oxide; lithium salt of stearic acid, magnesium salt, sodium salt, Calcium salt, barium salt, aluminum salt, zinc salt or iron salt, lithium salt of palmitic acid, magnesium salt, sodium salt, calcium salt, barium salt, aluminum salt, zinc salt or iron salt, lithium salt of lauric acid, Fatty acids such as magnesium salt, sodium salt, calcium salt, barium salt, aluminum salt, zinc salt, or iron salt, calcium salt or zinc salt of behenic acid, calcium salt of 12-hydroxystearic acid, magnesium salt or zinc salt, etc. Metal soaps containing metal salts;

The following antistatic agents;
Quaternary ammonium salt type cationic surfactant, betaine type amphoteric surfactant, alkyl phosphate type anionic surfactant, primary amine salt, secondary amine salt, tertiary amine salt, quaternary Cationic surfactants such as amine salts and pyridine derivatives,
Sulfated oil, soap, sulfated ester oil, sulfated amide oil, sulfated olefin salt of olefin, fatty alcohol sulfate, alkyl sulfate, fatty acid ethyl sulfonate, alkyl naphthalene sulfonate, alkyl benzene sulfonate , Anionic surfactants such as oxalate ester sulfonate and phosphate ester salt,
Partial fatty acid ester of polyhydric alcohol, ethylene oxide adduct of fatty alcohol, ethylene oxide adduct of fatty acid, ethylene oxide adduct of fatty amino or fatty acid amide, ethylene oxide adduct of alkylphenol, partial fatty acid ester of polyhydric alcohol An antistatic agent such as a nonionic surfactant such as an ethylene oxide adduct or polyethylene glycol, an amphoteric surfactant such as a carboxylic acid derivative or an imidazoline derivative, or an antistatic agent having a melting point exceeding 70 ° C. among them;

  Inorganic antiblocking agents such as aluminum silicate, synthetic silica, natural silica, zeolite, kaolin and diatomaceous earth, or organic antiblocking agents such as cross-linked polymethylmethacrylic acid;

  Carbon black, titanium oxide, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, perylene or perine pigment, quinophthalone pigment, diketopyrrolo-pyrrole pigment, dioxazine pigment, disazo condensation pigment and benzimidazolone pigment Pigments such as

  Flame retardants such as decabromobiphenyl, antimony trioxide, phosphorus flame retardant, aluminum hydroxide;

  2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-t-pentyl) Phenyl) ethyl] -4,6-di-t-pentylphenyl acrylate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, Tris (3,5-di-tert-butyl 4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -1,3,5 -Triazine-2,4,6- (1H, 3H, 5H) -trione, 2,2'-methylenebis (6-t-butyl-4-methylphenol), 4,4'-butylidenebis (6-t-butyl) -3-methyl Phenol), 4,4'-thiobis (6-t-butyl-3-phenolic antioxidant other than the phenol-based antioxidant (1), such as methyl phenol);

  In the production method of the present invention, 40 to 100 parts by weight of a mixture containing 3 to 70 parts by weight of the sulfur-based antioxidant represented by the formula (2) and the phenol-based antioxidant represented by the formula (1) is used. It is characterized by stirring granulation in a temperature range of 70 ° C. Specifically, the phenol-based antioxidant (1), the sulfur-based antioxidant (2), and, if necessary, additives other than (1) and (2) are added to the stirring granulator, The mixture is stirred at a temperature of 40 to 70 ° C., preferably 45 to 55 ° C. When the temperature of the mixture is 40 ° C. or higher, the production time of the granules tends to be shortened, and when it is 70 ° C. or lower, the antioxidant ability of the granules tends to improve.

  As a heating method for the agitation granulator, for example, when stirring the antioxidant in the agitation granulator, a method of setting using heat generated by shearing force, for example, the agitation granulator Examples thereof include a method of raising the temperature by passing a heating medium through a jacket, for example, a method of combining these methods.

Examples of methods of adding additives such as antioxidants to the agitation granulator include, for example, phenolic antioxidant (1), sulfur antioxidant (2), and additives as required. Then, a method of stirring and granulating, for example, adding the phenolic antioxidant (1) and additives as needed at once, stirring and then raising the temperature to a desired temperature, then adding the sulfurous antioxidant A method of adding and stirring and granulating, for example, similarly, raising the temperature while stirring the mixture to a desired temperature, and separately spraying a liquid obtained by heating the sulfur-based antioxidant (2) and stirring. The method of granulating is mentioned.
Unlike the conventional extrusion molding, the production method of the present invention can be mixed and granulated with one stirring granulator. Above all, the method of stirring and granulating is simplified after adding the phenolic antioxidant (1), the sulfurous antioxidant (2) and additives as needed, and then heating as necessary. Therefore, it is preferable.

The stirring granulator used in the present invention usually has a stirring blade inside, and the clearance (clearance) between the tip of the stirring blade and the wall surface inside the stirring granulator is usually 30 mm or less, preferably , An internal stirring type granulator having a clearance of about 0.1 to 5 mm (about 1 mm in the embodiment).
Specific examples of the agitation granulator include, for example, a high speed mixer (agitating rolling granulator), a Henschel mixer (high speed agitation granulator), a vertical granulator, a pharmamatrix, a super mixer, GRAL-Gral, and Shugi mixer. , Vertical mixers such as high-speed speeders and new speed kneaders, and horizontal mixers such as Redige mixers, Spartan Lusers, and pin mixers. Moreover, unlike the stirring blade for granulation, you may have the stirring blade called a chopper used for crushing and sizing of coarse granulated particles.

The stirring blade of the high speed mixer used in the examples will be described in more detail. The cross section of the stirring blade is 10 to 50 ° from the bottom (in the example, the center is 30 to 45 ° and the tip is 20 to 25 °). The mixture containing the antioxidant (1) and the like and the granules to be produced are scooped up from the bottom.
The blade tip in contact with the wall surface inside the agitation granulator may be designed appropriately, but in the case of the high-speed mixer used in the examples, it is inclined toward the center, and the mixture is centered. So that the mixture does not stay in the corners of the bottom and the wall.

  The stirring speed varies depending on the shape of the selected stirring blade, but the blade tip speed is usually about 2 to 40 m / s, preferably 4 to 20 m / s. When the blade tip speed is 40 m / s or less, it is preferable because the generated granule tends to suppress pulverization by the stirring blade, and when it is 2 m / s or more, the fluidity of the obtained granule tends to improve. preferable.

When mixing with a stirring granulator, it is preferable to mix in an inert gas atmosphere such as nitrogen from the viewpoint of suppressing the deterioration of the antioxidant.
After mixing, from the viewpoint of suppressing deterioration of the antioxidant, it is preferable to cool by cooling with cool air lower than the granulation temperature, preferably with cool air lower than 40 ° C. or storing in a refrigerator.
In addition, in order to stabilize the quality of the obtained granules, a large granule (for example, 5 mm or more, preferably 3 mm or more) or a small granule (for example, 0.1 mm or less, preferably 0.3 mm or less, more preferably 0). .5 mm or less) may be excluded.

  The granule group of the present invention thus obtained is the above-described granule aggregate, and the granule has a median diameter based on a weight of 0.1 to 5 mm. And the granule group whose dust scattering rate in Heubach test is 1 weight% or less has few dust scattering amounts at the time of handling, and is preferable also from a viewpoint on work environment. In particular, a group of granules composed of granules having a median diameter of 0.1 to 2 mm based on weight has good dispersibility when blended with plastic.

  The granule group of the present invention is suitable as a plastic stabilizer that is easily deteriorated by heat and light. An example of the plastic is a thermoplastic resin. The thermoplastic resin is preferably a polyolefin having a MI (melt index) in the range of 0.01 to 100 when a load of 2.16 kg is applied at 230 ° C. The plastic preferably has a median diameter based on weight in the range of 0.1 to 10 mm.

Examples of the plastic include polyolefin resin (polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc.), polystyrene resin (GP-PS, HI-PS, styrene-butadiene copolymer, acrylonitrile-styrene-butadiene three). Original copolymers, etc.), polyamide resins (6 nylon, 12 nylon, etc.), cyclic polyolefins, chlorine-containing polymers (polyvinyl chloride, chlorinated rubber, etc.), polyesters (polyethylene terephthalate, polybutylene terephthalate, etc.), polyurethane, engineering Examples thereof include plastics (polyphenylene ether, polycarbonate, etc.).
As the plastic, a thermoplastic resin is preferable, and polyolefin is particularly preferable.

These plastics can be stabilized by adding the granules of the present invention.
The addition amount of the granule group is preferably in the range of 0.005 to 5 parts by weight, more preferably in the range of 0.01 to 1 part by weight per 100 parts by weight of the plastic. If it is 0.005 parts by weight or more, it is preferable because the thermal stability of the plastic tends to be improved. If it is 5 parts by weight or less, there is a tendency not to impair the properties of the plastic, and the bleed of the additive is reduced. It is preferable because of its tendency.

  Examples of the method of blending the granule group of the present invention with plastic include, for example, a method in which the granule group and the plastic are mixed and then melt-kneaded with an extruder, or a solution in which the granule group is dissolved or suspended in a solvent in advance. Examples thereof include a method of feeding the solution after polymerization of the plastic and then removing the solvent by a method such as evaporation and distillation. The plastic stabilized in this way is processed into a product such as a film, a molding material or a pipe by a known method.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further in detail, this invention is not limited by these examples.

(Agitating granulator)
In the embodiment, as shown in FIG. 1, a three-blade stirring blade 2 having a rotating shaft is installed at the bottom of a bowl-shaped upper constricted cylindrical container 1, and a chopper 3 is horizontally disposed from the side wall. A high-speed mixer equipped with was used. Raw materials such as antioxidants were charged from a charging port (not shown) installed at the top of the container 1. Further, nitrogen was supplied to the container 1 from a line (not shown) to prevent deterioration of the antioxidant, and a bag filter 5 was installed so that raw materials and the like were not discharged from the container 1. The cooled granule was taken out from the granule discharge part 6.

(Median diameter measurement)
The weight-based median diameter was measured using a fully automatic sonic sieve robot shifter RPS-85c manufactured by Seishin Enterprise Co., Ltd.
(Dust scattering rate)
The dust scattering rate was measured by Dr. Hans Heubach GmbH & Co. A dust meter type I made by KG was used. The measurement method is to put the test material in a dust formation unit with a diameter of 277.2 mm and a capacity of 2.2 L, rotate at 36 rpm, ventilate 15 L / min of air, and when the aeration volume reaches 500 L, it is on the filter. The amount of fine powder produced was weighed and the weight percent based on the test material used was determined.
(Liquidity index)
The fluidity index was determined by measuring the bulk density, repose angle, spatula angle, and uniformity using a powder tester manufactured by Hosokawa Micron Co., Ltd. (Chemical Engineering Handbook Revised 5th Edition, p. 254).

  The raw materials used in the following Examples, Comparative Examples and Reference Examples are shown in Tables 1 to 3 below.

(Example 1: Production of granule group a)
751 g of phenolic antioxidant (1-1) and 751 g of sulfurous antioxidant (2-1) were put into a high-speed mixer (Fukae Powtech Co., Ltd., volume: 10 L).
After the addition, mixing was performed for 3 minutes at a rotating speed of the stirring blade of 240 rpm and a rotating speed of the chopper blade of 2000 rpm. Then, when the rotation speed of the stirring blade was increased to 400 rpm, the mixture was heated to 45 ° C. after 12 minutes. At this point, stirring was stopped and cooled to room temperature. 1.5 kg of the above-mentioned plastic additive granule group a was obtained.

(Examples 2 to 6: Production of granule groups b to f)
Instead of the raw material antioxidants (1-1) and (2-1) used in Example 1, the raw materials corresponding to each of Examples 2 to 6 described in Table 4 were used, and the same as in Example 1 The operation was performed to produce granule groups b to f. The granulation temperature is also shown in Table 4.

(Comparative Example 1: Production of additive mixture g)
In place of the raw material used in Example 1, the raw material described in Comparative Example 1 described in Table 4 was mixed at the weight described in Table 4, and the same operation as in Example 1 was performed to attempt granulation. The additive mixture g (powder) was obtained without granulation.

(Comparative Example 2: Production of additive cylindrical pellet group a ′)
1000 g of phenolic antioxidant (1-1) and 1000 g of sulfurous antioxidant (2-1) are added to a 10 L Henschel mixer and then mixed for 30 seconds at a stirring blade speed of 2400 rpm. It was. From the hopper (H) shown in FIG. 2, the above mixture was charged into a 30 mmφ twin screw extruder (manufactured by Nakatani Machinery Co., Ltd.). The operating conditions were as follows: C1 was 35 ° C., C2 was 40 ° C., C3 was 40 ° C., C4 was 40 ° C., A was 47 ° C., D was 47 ° C., and the screw rotation speed was 40 rpm. When extrusion granulation was performed under the above conditions, a strand composition having a diameter of 4 mmφ was obtained. This composition was cut into a length of about 5 mm using a cutter to obtain additive cylindrical pellet group a ′.
In addition, C1-C4 represents the preset heating temperature of the heating mixing part (cylinder part) of the extruder shown in FIG. D represents the set heating temperature of the die part of the extruder shown in FIG.

Example 7 (Measurement of physical property values of granule groups a to f, mixture g, and cylindrical pellet group a ′)
The median diameter based on the weight of the granule group, the mixture, the cylindrical pellet group ag and a ′ produced in Examples 1 to 6, Comparative Example 1 and Reference Example 1 and the dust scattering rate in the Heubach test were measured. Are listed in Table 5.
The smaller the dust scattering rate, the smaller the dust scattering during handling, which means that the working environment is improved.
Therefore, the granule group af of this invention has a small dust scattering rate, and a working environment is improved.

(Example 8: Performance evaluation of granule group af, mixture g, and cylindrical pellet group a ′)
The dispersibility of the granule groups a to f, the mixture g and the cylindrical pellet group a ′ produced in Examples 1 to 6 and Comparative Examples 1 and 2 with respect to polypropylene was measured.
Moreover, the thermal stability of the polypropylene composition which each mix | blended the granule group af, the mixture g, and the cylindrical pellet group a 'was measured.

<Preparation of pellets for evaluation>
1.4 kg of polypropylene [MI = 3 (230 ° C., 2,16 kg · f)], 0.7 g of calcium stearate, and 1.05 g of additive granule group for plastic (a) were dry blended. The obtained mixture was put into a 30 mmφ single screw extruder (manufactured by Tanabe Plastics) from a hopper. Subsequently, it was operated under the conditions of an extrusion temperature of 220 ° C. and a screw rotation speed of 50 rpm. Detailed operating conditions are described below.

After feeding into the extruder from the hopper, the polypropylene pellets obtained 5 to 10 minutes later are designated PP-1, the pellets obtained 10 to 15 minutes later are designated PP-2, and so on. The pellets obtained up to -20 minutes later were PP-3, and the pellets obtained by 20-25 minutes were designated PP-4.
The measurement of the staying MI value up to the pellets PP-1 to PP-4 was performed under the conditions described below.

  Put 5g PP-1 into cylinder of MI meter at cylinder temperature of 280 ° C, then hold for 20 minutes with piston set, then apply 2.16kg load and measure stay MI value at 280 ° C did. Similarly, the residence MI value at 280 ° C. was measured for PP-2 to PP-4, and the measurement results are shown in Table 6.

For granule group b to f, mixture g and cylindrical pellet a ′, except that granule group a was changed to b to f, g and a ′, pellets were prepared in the same manner, and the retention MI value was measured. The results are shown in Table 6 below.
The smaller the staying MI value, the better the thermal stability. Moreover, the smaller the dispersion (standard deviation) of the staying MI value between PP-1 and PP-4, the better the dispersibility in polypropylene and the better the polypropylene composition with uniform thermal stability.
Therefore, it turns out that the granule group af of this invention has the favorable dispersibility to a polypropylene, and is excellent in the heat stability effect with respect to a polypropylene. Furthermore, it turns out that the polypropylene composition which mix | blended the granule group af of this invention is comparatively homogeneous, and is excellent also in thermal stability.

* The addition amount of each additive represents the number of parts by weight per 100 parts by weight of polypropylene.

The granule group of the present invention produces almost no dust, is excellent in fluidity, and has good dispersibility in plastics such as polyolefin, so that a polyolefin resin composition excellent in thermal stability can be produced. Possible

Cross-sectional schematic diagram of the agitation granulator (high speed mixer) used in the examples Schematic of the extruder used in Comparative Example 2

Explanation of symbols

1 Cylindrical container
2 Stirring blade
3 Chopper
4 Motor
5 Bug filter
6 Granule discharge part (A) Adapter part
Adapter maximum mixture temperature measurement position (B) Discharge port (C) Heating and mixing unit
(C1) to (C4) Set temperature position of heating and mixing section (D) Die section
Set temperature position of die part (E) Screw cylinder (H) Raw material input part

Claims (12)

A group of granules comprising a phenolic antioxidant represented by the formula (1) and a sulfur antioxidant represented by the formula (2), the phenolic antioxidant (1) and the sulfur antioxidant A granule group in which the content of the sulfur-based antioxidant (2) with respect to 100 parts by weight in total of (2) is 3 to 70 parts by weight.

_{(R 2 -Y-S-C} 2 H 4 CO 2) m -Z (2)
[In Formula (1), R ₁ represents an alkyl group having 1 to 8 carbon atoms, and X represents an n-valent alcohol residue having 1 to 18 carbon atoms which may include a hetero atom and / or a cyclic group. , N represents an integer of 1 to 4,
In Formula (2), R ₂ represents an alkyl group having 12 to 18 carbon atoms, Y represents a single bond or a —C ₂ H ₄ CO ₂ — group, and Z represents an m-valent alcohol residue having 5 to 18 carbon atoms. Represents a group, and m represents an integer of 1 to 4. ]   The granule group according to claim 1, wherein the median diameter (weight basis) of the granule contained in the granule group is 0.1 to 5 mm.   The granule group according to claim 1 or 2, wherein a dust scattering rate of the granule group measured by a Heubach test is 1% by weight or less.   The sulfur-based antioxidant represented by the formula (2) contains 3,3′-thiodipropionic acid di-n-dodecyl ester, 3,3′-thiodipropionic acid di-n-tetradecyl ester, and 3,3 ′. The granule group according to any one of claims 1 to 3, which is at least one selected from the group consisting of -thiodipropionic acid di-n-octadecyl ester.   The phenolic antioxidant represented by formula (1) is 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethyl. Ethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythrityl ester and bis The granule according to any one of claims 1 to 4, which is at least one selected from the group consisting of {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionic acid} triethyleneglycolyl ester. group.   Neutralizing agent, lubricant, phosphorus antioxidant, hindered amine light stabilizer, ultraviolet absorber, metal soap, antistatic agent, anti-blocking agent, pigment, flame retardant, filler, and formula (1) The granule group according to any one of claims 1 to 5, further comprising at least one additive selected from an additive group consisting of a phenolic antioxidant other than a phenolic antioxidant.   Agitation granulation of 100 parts by weight of a mixture containing 3 to 70 parts by weight of the sulfur-based antioxidant represented by the formula (2) and the phenol-based antioxidant represented by the formula (1) in a temperature range of 40 to 70 ° C. A method for producing a granule group.   The agitation granulator has an agitation blade inside the agitation granulator, and agitation granulation is performed with an agitation granulator having a clearance between the tip of the agitation blade and a wall surface inside the agitation granulator of 30 mm or less. Manufacturing method.   The plastic composition formed by mix | blending 0.005-5 weight part with the granule group in any one of Claims 1-6 with respect to 100 weight part of plastics.   The composition according to claim 9, wherein the plastic is a thermoplastic resin.   The composition of claim 10, wherein the plastic is a polyolefin.   The plastic stabilization method which mix | blends 0.005-5 weight part of the granule groups in any one of Claims 1-6 per 100 weight part of plastics.

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