JP2024157693A - Method for producing additive granules and plastic composition - Google Patents

Abstract

To provide a granulated material containing 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, the granulated material exhibiting excellent flowability.SOLUTION: An additive granulated material is formed from a composition (A) containing an antioxidant (a) containing a phenolic antioxidant (1), and contains 40-100 mass% of a phenolic antioxidant (1-1-1) with respect to the total amount of the phenolic antioxidant (1). The phenolic antioxidant (1-1-1) is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane having a crystal structure exhibiting sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6°, as measured by powder X-ray diffraction using X-rays having a Cu-Kα wavelength.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing additive granules and plastic compositions.

3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane is a hydroxyphenylpropionic acid ester known as a phenolic antioxidant, and is known to have an ε, δ, αβ, or γ crystal structure (Patent Document 1).

Among these, the ε crystal has a crystal structure that shows a sharp X-ray diffraction peak at a diffraction angle 2θ = 7.9° when measured by X-ray diffraction, and a powder of the ε crystal hydroxyphenylpropionic acid ester is also known (Patent Document 2).

Japanese Patent Application Publication No. 6-87860 JP 2015-157853 A

3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane has an excellent antioxidant effect, but when the phenol-based antioxidant is added to plastics and used as a granule, the fluidity of the granule may be deteriorated. In particular, such granules are often used after a certain period of time has passed since production, such as when they are transported or stored in a warehouse, and it has been found that the fluidity of the granules may be deteriorated during such storage periods. Therefore, the present invention aims to provide a granule containing 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, which has good fluidity.

As a result of detailed investigation into the factors that affect the fluidity of granulated materials, the inventors discovered that the crystal structure of the phenolic antioxidant affects the fluidity of granulated materials, which led to the completion of the present invention.

That is, the present invention includes the following preferred embodiments.
[1] An additive granule formed from a composition (A) containing an antioxidant (a) containing a phenolic antioxidant (1), the additive granule containing 40 to 100 mass% of a phenolic antioxidant (1-1-1) which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane having a crystal structure which shows sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6° in X-ray diffraction measurement using X-rays of Cu-Kα wavelength.
[2] The additive granule according to [1], wherein the content of the phenolic antioxidant (1-1-1) is 40 to 100 mass% based on the total amount of the phenolic antioxidant (1-1) which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane contained in the phenolic antioxidant (1).
[3] The additive granule according to [1] or [2], wherein the ratio of the amount of the phenolic antioxidant (1-1-1) to the amount of the phenolic antioxidant (1-1-2) which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane having a crystal structure that shows a sharp X-ray diffraction peak at a diffraction angle 2θ=7.9° in X-ray diffraction measurement using X-rays of Cu-Kα wavelength is (1-1-1):(1-1-2)=100:0 to 40:60.
[4] The additive granule according to any one of [1] to [3], wherein the amount of the phenol-based antioxidant (1) contained in the composition (A) is 2 to 30 mass% based on the total amount of the composition (A).
[5] The additive granule according to any one of [1] to [4], wherein the amount of the antioxidant (a) contained in the composition (A) is 25 to 100 mass% based on the total amount of the composition (A).
[6] The additive granule according to any one of [1] to [5], wherein the antioxidant (a) further contains a phosphorus-based antioxidant (2) and/or a sulfur-based antioxidant (3).
[7] The additive granule according to [6], wherein the total amount of the phenol-based antioxidant (1), the phosphorus-based antioxidant (2) and/or the sulfur-based antioxidant (3) contained in the composition (A) is 25 to 100 mass% based on the total amount of the composition (A).
[8] The additive granule according to [6] or [7], wherein the amount of the phenol-based antioxidant (1) is 5 to 30 mass% and the total amount of the phosphorus-based antioxidant (2) and/or the sulfur-based antioxidant (3) is 70 to 95 mass% based on the total amount of the antioxidant (a).
[9] The additive granule according to any one of [6] to [8], wherein the amount of the phenol-based antioxidant (1) is 10 to 15 mass%, the amount of the phosphorus-based antioxidant (2) is 48 to 53 mass%, and the amount of the sulfur-based antioxidant (3) is 35 to 40 mass%, relative to the total amount of the antioxidant (a).
[10] The additive granule according to any one of [1] to [9], wherein the composition (A) further contains at least one additive selected from the group consisting of a neutralizing agent, a lubricant, a hindered amine light stabilizer, an ultraviolet absorber, a metal soap, an antistatic agent, an antiblocking agent, a pigment, a flame retardant, a filler, a nucleating agent, a plasticizer, a processing aid, a foaming agent, and an emulsifier.
[11] The additive granule according to any one of [1] to [10], wherein the additive granule has a median diameter (by mass) of 0.1 to 7 mm.
[12] A method for producing a plastic composition, comprising a step of blending 0.005 to 10 parts by mass of the additive granule according to any one of [1] to [11] with respect to 100 parts by mass of plastic.
[13] The method for producing a plastic composition according to [12], wherein the plastic is a thermoplastic resin.
[14] The method for producing a plastic composition according to claim [12], wherein the plastic is a polyolefin-based resin.

According to the present invention, it is possible to provide a granulated product containing 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, which has good flowability.

FIG. 2 is a diagram showing the results of X-ray diffraction measurement of the compound (1-1-1) used in the examples using X-rays with a Cu-Kα wavelength. FIG. 2 is a diagram showing the results of X-ray diffraction measurement of the compound (1-1-2) used in the examples using X-rays with a Cu-Kα wavelength.

The following describes in detail the embodiments of the present invention. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention. In addition, when multiple upper and lower limit values are listed for a particular feature, any of these upper and lower limit values can be combined to create a suitable numerical range.

The additive granule of the present invention is a granule formed from composition (A), and the composition (A) contains at least one or two or more phenolic antioxidants (1) as antioxidant (a). The phenolic antioxidant (1) contains 40 to 100 mass% of the total amount of the phenolic antioxidant (1-1-1), which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane having a crystal structure that shows sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6° in X-ray diffraction measurement using X-rays of Cu-Kα wavelength. In addition, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, which has a crystal structure that shows sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6°, has a δ crystal structure, and this compound in δ crystal form is referred to as phenolic antioxidant (1-1-1) in this specification.

It was surprisingly found that the fluidity of the additive granules was improved by containing a specific amount of phenolic antioxidant (1-1-1) in the phenolic antioxidant (1) in the composition (A) that forms the additive granules. It was also found that the fluidity of the additive granules could be maintained even after a certain period of time had passed after the granules were produced.

で表されるフェノール系酸化防止剤である、３，９－ビス［２－｛３－（３－ｔ－ブチル－４－ヒドロキシ－５－メチルフェニル）プロピオニルオキシ｝－１，１－ジメチルエチル］－２，４，８，１０－テトラオキサスピロ［５・５］ウンデカン（１－１）が挙げられる。フェノール系酸化防止剤（１－１）は、特開平６－８７８６０号公報に記載されるように、Ｃｕ－Ｋα波長のＸ線を用いたＸ線回折測定において、回折角２θ＝４．２°および２θ＝１０．６°に鋭いＸ線回折ピークを示すδ晶、回折角２θ＝７．９°に鋭いＸ線回折ピークを示すε晶、回折角２θ＝２．８°、２θ＝８．７°、２θ＝１１．７°に鋭いＸ線回折ピークを示すαβ晶、固有のＸ線回折ピークを示さないγ晶などの結晶構造を有することが知られている。本明細書において、式（Ｉ）で表されるフェノール系酸化防止剤（１－１）のうち、回折角２θ＝４．２°および２θ＝１０．６°に鋭いＸ線回折ピークを示す結晶構造を有するδ晶の化合物をフェノール系酸化防止剤（１－１－１）とも称し、回折角２θ＝７．９°に鋭いＸ線回折ピークを示す結晶構造を有するε晶の化合物をフェノール系酸化防止剤（１－１－２）とも称し、回折角２θ＝２．８°、２θ＝８．７°、２θ＝１１．７°に鋭いＸ線回折ピークを示す結晶構造を有するαβ晶の化合物をフェノール系酸化防止剤（１－１－３）とも称し、固有のＸ線回折ピークを示さない結晶構造を有するγ晶の化合物をフェノール系酸化防止剤（１－１－４）とも称する。なお、上記の特定のＸ線回折ピークを示す結晶構造を有するフェノール系酸化防止剤は、それぞれ、単一の結晶系であり、通常、特定の融点を有する。具体的には、回折角２θ＝４．２°および２θ＝１０．６°に鋭いＸ線回折ピークを示す結晶構造を有するδ晶のフェノール系酸化防止剤（１－１－１）の融点は、通常、約１２４～１２７℃である。同様に、フェノール系酸化防止剤（１－１－２）の融点は、通常、約１１６～１１９℃であり、フェノール系酸化防止剤（１－１－３）の融点は、通常、約１０４～１０９℃であり、フェノール系酸化防止剤（１－１－４）の融点は、通常、約４５～５５℃である。 [Antioxidant (a)]
(Phenol-based antioxidant (1))
In the present invention, the composition (A) contains an antioxidant (a) containing at least a phenol-based antioxidant (1). Examples of the phenol-based antioxidant (1) include those represented by the formula (I):

and 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (1-1), which is a phenolic antioxidant represented by the formula: As described in JP-A-6-87860, the phenolic antioxidant (1-1) is known to have a crystal structure such as a δ crystal exhibiting sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6°, an ε crystal exhibiting a sharp X-ray diffraction peak at diffraction angle 2θ=7.9°, an αβ crystal exhibiting sharp X-ray diffraction peaks at diffraction angles 2θ=2.8°, 2θ=8.7°, and 2θ=11.7°, and a γ crystal exhibiting no specific X-ray diffraction peak, in an X-ray diffraction measurement using X-rays of Cu-Kα wavelength. In this specification, among the phenolic antioxidants (1-1) represented by formula (I), a δ-crystalline compound having a crystal structure exhibiting sharp X-ray diffraction peaks at diffraction angles 2θ = 4.2 ° and 2θ = 10.6 ° is also referred to as a phenolic antioxidant (1-1-1), a ε-crystalline compound having a crystal structure exhibiting sharp X-ray diffraction peaks at diffraction angles 2θ = 7.9 ° is also referred to as a phenolic antioxidant (1-1-2), an αβ-crystalline compound having a crystal structure exhibiting sharp X-ray diffraction peaks at diffraction angles 2θ = 2.8 °, 2θ = 8.7 °, and 2θ = 11.7 ° is also referred to as a phenolic antioxidant (1-1-3), and a γ-crystalline compound having a crystal structure that does not exhibit a specific X-ray diffraction peak is also referred to as a phenolic antioxidant (1-1-4). Note that the phenolic antioxidants having a crystal structure exhibiting the above specific X-ray diffraction peaks are each a single crystal system, and usually have a specific melting point. Specifically, the melting point of the δ-crystalline phenolic antioxidant (1-1-1) having a crystal structure showing sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6° is usually about 124 to 127° C. Similarly, the melting point of the phenolic antioxidant (1-1-2) is usually about 116 to 119° C., the melting point of the phenolic antioxidant (1-1-3) is usually about 104 to 109° C., and the melting point of the phenolic antioxidant (1-1-4) is usually about 45 to 55° C.

The composition (A) may contain, as the antioxidant (a), one type of phenol-based antioxidant, two or more types of phenol-based antioxidants, or an antioxidant other than a phenol-based antioxidant, but it at least contains a compound represented by formula (I) in the δ crystal form having a crystal structure that shows sharp X-ray diffraction peaks at diffraction angles 2θ = 4.2° and 2θ = 10.6°, i.e., a phenol-based antioxidant (1-1-1).

The amount of the phenolic antioxidant (1-1-1) relative to the total amount of the phenolic antioxidant (1) contained in the composition (A) is 40 to 100% by mass. If the amount is less than 40% by mass, it becomes difficult to obtain the effect of improving the fluidity of the granulated product by the phenolic antioxidant (1-1-1). The amount of the phenolic antioxidant (1-1-1) is 40% by mass or more, but from the viewpoint of improving fluidity, it is preferably 50% by mass or more, more preferably 75% by mass or more, even more preferably 90% by mass or more, and even more preferably 99% by mass or more. There is no particular upper limit to the amount, and it may be 100% by mass or less.

In one embodiment of the present invention, the content of the phenolic antioxidant (1-1-1) is, from the viewpoint of fluidity of the granules, preferably 40 to 100% by mass, more preferably 50 to 100% by mass, even more preferably 75 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 99 to 100% by mass, based on the total amount of the phenolic antioxidant (1-1), which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, contained in the phenolic antioxidant (1).

［式（ＩＩ）中、Ｒ^１は炭素数１～９のアルキル基を表し、Ｘはヘテロ原子および／または環状基を含んでいてもよい炭素数１～１８のｎ価のアルコール残基を表し、ｎは２または４の整数を表す］
で表されるフェノール系酸化防止剤（但し、式（Ｉ）で表されるフェノール系酸化防止剤は除く）、１，３，５－トリス（４－ｔ－ブチル－３－ヒドロキシ－２，６－ジメチルベンジル）イソシアヌル酸、４，４‘－チオビス（２－ｔ－ブチル－５－メチルフェノール）、１，３，５－トリス（３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジル）－１，３，５－トリアジン－２,４,６（１Ｈ，３Ｈ，５Ｈ）－トリオン、Ｎ，Ｎ‘－（ヘキサン－１,６－ジイル）ビス［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロパンアミド］、４，４’－ブチリデンビス（６－ｔ－ブチル－ｍ－クレゾール）等が挙げられる。 The phenol-based antioxidant (1) contained in the composition (A) may be, in addition to the above-mentioned phenol-based antioxidant (1-1-1), an antioxidant having a crystal system other than a δ crystal represented by formula (I) (for example, the above-mentioned phenol-based antioxidants (1-1-2), (1-1-3), or (1-1-4)), or a phenol-based antioxidant represented by formula (II):

[In formula (II), R ¹ represents an alkyl group having 1 to 9 carbon atoms, X represents an n-valent alcohol residue having 1 to 18 carbon atoms which may contain a heteroatom and/or a cyclic group, and n represents an integer of 2 or 4]
(excluding phenol-based antioxidants represented by formula (I)), 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, 4,4'-thiobis(2-t-butyl-5-methylphenol), 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propanamide], and 4,4'-butylidenebis(6-t-butyl-m-cresol).

R ¹ in formula (II) is, for example, a linear alkyl group having 1 to 8 carbon atoms, such as a methyl group, a t-butyl group, a t-pentyl group, or a t-octyl group, or a branched alkyl group having 3 to 8 carbon atoms. ^{R 1} is preferably a methyl group or a t-butyl group.

In formula (II), n is 2 or 4.

X in formula (II) is an n-valent alcohol residue, and X contains 1 to 18 carbon atoms. Here, the alcohol residue means a substituent obtained by removing a hydroxyl group from an alcohol. X may contain a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, or may contain a cyclic group such as an alicyclic group such as a cyclopentane structure or a cyclohexane structure, or an aromatic group such as a benzene structure. A carbon atom in the cyclic group may be substituted with a heteroatom.

Examples of alcohols that provide alcohol residues include stearyl alcohol, decyl alcohol, octyl alcohol, triethylene glycol, 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and pentaerythritol, of which stearyl alcohol, triethylene glycol, 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and pentaerythritol are preferred.

Examples of phenolic compounds (II) include bis{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionic acid}triethylene glycolyl ester, tetrakis{3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionic acid}pentaerythrityl ester, etc. However, the phenolic antioxidant represented by formula (I) is not included in the phenolic antioxidant represented by formula (II).

The composition (A) forming the additive granules contains a phenolic antioxidant (1), and from the viewpoint of heat coloration resistance (the property of suppressing coloration even when kneaded and molded at high temperatures), the total amount of the phenolic compound represented by formula (I) and the compound represented by formula (II) contained in the phenolic antioxidant (1) is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and even more preferably 99 parts by mass or more, per 100 parts by mass of the phenolic antioxidant (1) contained in the composition (A).

The amount of phenolic antioxidant (1) contained in composition (A) forming the additive granules is preferably 2% by mass or more, more preferably 2.5% by mass or more, and even more preferably 3% by mass or more, based on the total amount of composition (A), from the viewpoint of improving processing stability, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the total amount of composition (A), from the viewpoint of reducing costs.

The amount of antioxidant (a) contained in composition (A) forming the additive granules is preferably 25% by mass or more, more preferably 26% by mass or more, and even more preferably 27% by mass or more, based on the total amount of composition (A), from the viewpoint of improving processing stability. There is no particular upper limit to the amount, and it may be 100% by mass or less based on the total amount of composition (A), but from the viewpoint of cost reduction, it is preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less.

In the composition (A) that forms the additive granules, the ratio (1-1-1):(1-1-2) of the amount of the phenolic antioxidant (1-1-1) contained as the phenolic antioxidant (1) to the amount of the phenolic antioxidant (1-1-2) is preferably 100:0 to 40:60, more preferably 100:0 to 45:55, and even more preferably 100:0 to 50:50. In this embodiment, the additive granules may contain the above components as a whole granule. Therefore, the additive granule may be, for example, an additive granule made of a composition (A) containing a phenolic antioxidant (1-1-1), an additive granule made of a composition (A) containing a phenolic antioxidant (1-1-1) and a phenolic antioxidant (1-1-2), or a mixture obtained by mixing an additive granule (a1) made of a composition (A) containing a phenolic antioxidant (1-1-1) and an additive granule (b1) made of a composition (B) containing a phenolic antioxidant (1-1-2) in such a ratio that the amount of the phenolic antioxidant (1-1-1) and the amount of the phenolic antioxidant (1-1-2) are preferably 100:0 to 40:60, more preferably 100:0 to 45:55, and even more preferably 100:0 to 50:50.

The composition (A) forming the additive granules may contain only the phenol-based antioxidant (1) as the antioxidant (a), or may further contain an antioxidant other than the phenol-based antioxidant (1). Examples of antioxidants other than the phenol-based antioxidant (1) include phosphorus-based antioxidants (2), sulfur-based antioxidants (3), and hindered amine-based antioxidants. The composition (A) may further contain, for example, a phosphorus-based antioxidant (2) and/or a sulfur-based antioxidant (3) as the antioxidant (a).

［式（ＩＩＩ）中、Ｒ^３、Ｒ^４、およびＲ^５は、それぞれ独立に、炭素数１～８の直鎖アルキル基、炭素数３～８の分岐鎖アルキル基または水素原子を表す］
で示されるリン系酸化防止剤、式（ＩＶ）：

［式（ＩＶ）中、Ｒ^６、Ｒ^７、およびＲ^８は、それぞれ独立に、炭素数１～８の直鎖アルキル基、炭素数３～８の分岐鎖アルキル基または水素原子を表す］
で表されるリン系酸化防止剤、および／または式（Ｖ）：

［式（Ｖ）中、Ｒ^９、Ｒ^１０、およびＲ^１１は、それぞれ独立に、水素原子、炭素数１～８の直鎖アルキル基、炭素数３～８の分岐鎖アルキル基、炭素数５～８のシクロアルキル基、炭素数６～１２のアルキルシクロアルキル基、炭素数７～１２のアラルキル基またはフェニル基を表す］
で表されるリン系酸化防止剤であることが好ましい。 (Phosphorus-based antioxidant (2))
Examples of the phosphorus-based antioxidant (2) include 2,2'-methylenebis(4,6-di-t-butylphenyl)2-ethylhexyl phosphite and triisodecyl phosphite. The composition (A) may contain one type of phosphorus-based antioxidant as the phosphorus-based antioxidant (2), or may contain two or more types of phosphorus-based antioxidants. From the viewpoint of improving heat coloration resistance and oxidation resistance, the phosphorus-based antioxidant is preferably a compound represented by the formula (III):

[In formula (III), R ³ , R ⁴ , and R ⁵ each independently represent a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, or a hydrogen atom]
a phosphorus-based antioxidant represented by formula (IV):

[In formula (IV), R ⁶ , R ⁷ , and R ⁸ each independently represent a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, or a hydrogen atom]
and/or a phosphorus-based antioxidant represented by the formula (V):

[In formula (V), R ⁹ , R ¹⁰ , and R ¹¹ each independently represent a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group]
It is preferable that the antioxidant is a phosphorus-based antioxidant represented by the formula:

In formula (III), R ³ , R ⁴ , and R ⁵ each independently represent a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, or a hydrogen atom. Examples of linear alkyl groups and branched alkyl groups include a methyl group, a t-butyl group, a t-pentyl group, and a t-octyl group. R ³ , R ⁴ , and R ⁵ are preferably a hydrogen atom, a methyl group, or a t-butyl group. Examples of phosphorus-based antioxidants represented by formula (III) include tris(nonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, and the like.

In formula (IV), R ⁶ , R ⁷ , and R ⁸ each independently represent a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, or a hydrogen atom. Examples of the linear alkyl group and the branched alkyl group include the same groups as those exemplified for R ³ in formula (III). R ⁶ , R ⁷ , and R ⁸ are preferably a hydrogen atom, a methyl group, or a t-butyl group. Examples of the phosphorus-based antioxidant represented by formula (IV) include bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, and the like.

In formula (V), R ⁹ , R ¹⁰ , and R ¹¹ each independently represent a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. Examples of linear alkyl groups and branched alkyl groups include the same groups as those exemplified for R ³ in formula (III). Examples of cycloalkyl groups having 5 to 8 carbon atoms include a cyclopentyl group, a cyclohexyl group, and a cyclopentyl group. Examples of alkylcycloalkyl groups having 6 to 12 carbon atoms include a methylcyclopentyl group, a methylcyclohexyl group, and a dimethylcyclohexyl group. Examples of aralkyl groups having 7 to 12 carbon atoms include a benzyl group.

In formula (V), R ⁹ preferably represents a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcycloalkyl group having 6 to 12 carbon atoms, and more preferably represents a t-alkyl group, a cyclohexyl group, or a 1-methylcyclohexyl group.

In formula (V), R ¹⁰ preferably represents a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcycloalkyl group having 6 to 12 carbon atoms, and more preferably represents a methyl group, a t-butyl group, or a t-pentyl group.

In formula (V), R ¹¹ preferably represents a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, or a branched alkyl group having 3 to 8 carbon atoms, and more preferably represents a hydrogen atom or a methyl group.

In formula (V), B represents a single bond, a sulfur atom or a -CHR ¹² - group, and R ¹² represents a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms. Examples of the linear alkyl group having 1 to 8 carbon atoms, the branched alkyl group having 3 to 8 carbon atoms and the cycloalkyl group having 5 to 8 carbon atoms are the same as those for R ^9. Examples of the -CHR ¹² - group include a methylene group, an ethylidene group, a propylidene group and a 1-cyclohexylmethyl group. B preferably represents a single bond, a methylene group or an ethylidene group.

In formula (V), A represents an alkylene group having 2 to 8 carbon atoms or a *-C(=O)-R ¹³ - group, R ¹³ represents a single bond or an alkylene group having 1 to 8 carbon atoms, and the * symbol represents a bond to the oxygen atom side of the >P-O- portion. Examples of the alkylene group having 1 to 8 carbon atoms include a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group. A is preferably an alkylene group having 2 to 4 carbon atoms or the above-mentioned *-C(=O)-R ¹³ - group. The carbon-carbon bond of the alkylene group having 2 to 4 carbon atoms may be interrupted by a group containing a hetero atom. In this case, examples of the group containing a hetero atom include an -O-C(=O)- or -C(=O)-O- group. ^{R 13} is preferably an alkylene group having 1 to 4 carbon atoms.

Either Y or Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms, or a branched alkyl group having 3 to 8 carbon atoms, but when Y is a hydroxyl group, it is preferable that either R ¹² or R ¹³ represents a linear alkyl group having 3 to 8 carbon atoms, a branched alkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. Examples of the alkoxy group having 1 to 8 carbon atoms include a methoxy group, an ethoxy group, and a t-butoxy group, and examples of the aralkyloxy group having 7 to 12 carbon atoms include a benzyloxy group.

When Y in formula (V) is a hydroxyl group, Z is more preferably a hydrogen atom or a methyl group, and one of R ¹² and R ¹³ is more preferably a t-butyl group.

When Z in formula (V) is a hydroxyl group, it is preferable that R ¹³ is a methyl group, Y is a hydrogen atom, and R ¹² is a t-butyl group.

In addition, R ⁹ , R ¹⁰ and R ¹¹ in formula (V) may be the same as or different from each other.

Preferred examples of phosphorus-based antioxidants represented by formula (V) include the following: 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepine, Xaphosphepine, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, etc.

(Sulfur-based antioxidants (3))
An example of the sulfur-based antioxidant (3) is bis[2-methyl-4-{3-n-alkyl(C12 or C14)thiopropionyloxy}-5-t-butylphenyl]sulfide. The composition (A) may contain one type of sulfur-based antioxidant as the sulfur-based antioxidant (3), or may contain two or more types of sulfur-based antioxidants. From the viewpoint of improving heat coloration resistance and antioxidant properties, the sulfur-based antioxidant is preferably a sulfur-based antioxidant represented by the formula (VI):
(R ¹⁴ -DSC ₂ H ₄ CO ₂ ) _m -E (VI)
[In formula (VI), R ¹⁴ represents a linear alkyl group having 12 to 18 carbon atoms or a branched alkyl group having 12 to 18 carbon atoms, D represents a single bond or a —C ₂ H ₄ CO ₂ — group, m represents an integer of 1 to 4, and E represents an m-valent alcohol residue having 5 to 18 carbon atoms]
It is preferable that the antioxidant is a sulfur-based antioxidant represented by the formula:

In formula (VI), R ¹⁴ is preferably a dodecyl group, a tetradecyl group, an octadecyl group, or the like. The alcohol residue in E refers to the portion of the alcohol other than the hydroxyl group. Examples of alcohols that provide the alcohol residue include dodecyl alcohol, tetradecyl alcohol, octadecyl alcohol, and pentaerythritol.

In particular, in the sulfur-based antioxidant represented by formula (VI), when D in formula (VI) is a single bond, a compound in which R ¹⁴ is a dodecyl group, m is 4, and E is a pentaerythritol residue is preferred. Also, when D is a -C ₂ H ₄ CO ₂ - group, it is preferred that R ¹⁴ is a dodecyl group, a tetradecyl group, or an octadecyl group, m is 1, and E is an alcohol residue having 12, 14, or 18 carbon atoms corresponding to the above R ¹⁴ .

When D is a -C ₂ H ₄ CO ₂ - group, the alcohol residue is usually bonded to D via an ester group. Specifically, when E is monovalent, it is -C ₂ H ₄ CO ₂ -Z.

Examples of sulfur-based antioxidants represented by formula (VI) include 3,3'-thiodipropionic acid di-n-dodecyl ester, 3,3'-thiodipropionic acid di-n-tetradecyl ester, 3,3'-thiodipropionic acid di-n-octadecyl ester, and tetrakis(3-dodecylthiopropionic acid) pentaerythrityl ester.

In a preferred embodiment of the present invention, when the composition (A) forming the additive granule contains, as the antioxidant (a), a phenol-based antioxidant (1), a phosphorus-based antioxidant (2) and/or a sulfur-based antioxidant (3), the total amount of the phenol-based antioxidant (1), the phosphorus-based antioxidant (2) and/or the sulfur-based antioxidant (3) is preferably 25 to 100% by mass, more preferably 26 to 90% by mass, and even more preferably 27 to 80% by mass, based on the total amount of the composition (A).

In a more preferred embodiment of the present invention, when the composition (A) forming the additive granule contains, as the antioxidant (a), a phenol-based antioxidant (1) and a phosphorus-based antioxidant (2) and/or a sulfur-based antioxidant (3), the amount of the phenol-based antioxidant (1) relative to the total amount of the antioxidant (a) is preferably 5 to 30% by mass, more preferably 8 to 20% by mass, and even more preferably 10 to 15% by mass, and the total amount of the phosphorus-based antioxidant (2) and/or the sulfur-based antioxidant (3) relative to the total amount of the antioxidant (a) is preferably 70 to 95% by mass, more preferably 80 to 92% by mass, and even more preferably 85 to 90% by mass. The composition (A) contains 40 to 100% by mass of the phenol-based antioxidant (1-1-1) relative to the total amount of the phenol-based antioxidant (1).

In a more preferred embodiment of the present invention, when the composition (A) forming the additive granule contains, as the antioxidant (a), a phenol-based antioxidant (1), a phosphorus-based antioxidant (2), and a sulfur-based antioxidant (3), the amount of the phenol-based antioxidant (1) relative to the total amount of the antioxidant (a) is preferably 10 to 15% by mass, more preferably 10 to 14% by mass, and even more preferably 11 to 14% by mass, the amount of the phosphorus-based antioxidant (2) is preferably 48 to 53% by mass, more preferably 49 to 52% by mass, and even more preferably 49 to 51% by mass, and the amount of the sulfur-based antioxidant (3) is preferably 35 to 40% by mass, more preferably 36 to 39% by mass, and even more preferably 36 to 38% by mass. The composition (A) contains 40 to 100% by mass of the phenol-based antioxidant (1-1-1) relative to the total amount of the phenol-based antioxidant (1).

From the viewpoint of improving heat discoloration resistance and antioxidant properties, the phenolic antioxidant (1) is preferably a compound selected from the group consisting of phenolic antioxidants represented by formula (I) and phenolic antioxidants represented by formula (II). However, from the viewpoint of obtaining an additive granule having high fluidity, the phenolic antioxidant (1-1-1) is contained in an amount of 40 to 100 mass % based on the total amount of the phenolic antioxidant (1).
From the viewpoint of improving heat discoloration resistance and antioxidant properties, the phosphorus-based antioxidant (2) is preferably a compound selected from the group consisting of phosphorus-based antioxidants represented by formula (III), phosphorus-based antioxidants represented by formula (IV), and phosphorus-based antioxidants represented by formula (V), and is more preferably a phosphorus-based antioxidant represented by formula (III).
From the viewpoint of improving heat discoloration resistance and antioxidant properties, the sulfur-based antioxidant (3) is preferably a compound selected from the group consisting of sulfur-based antioxidants represented by formula (VI), and more preferably a _{sulfur-based antioxidant in which D in formula (VI) is a -C2H4CO2- group ,} ^R14 is a dodecyl group, a tetradecyl group or an octadecyl group, m is 1, and E is an alcohol residue having 12, 14 or 18 carbon atoms corresponding to the above ^R14 .

(Other Additives)
The composition (A) forming the additive granules may further contain various additives known in the art in addition to the antioxidant (a). Examples of such additives include at least one additive selected from the group consisting of neutralizers, lubricants, hindered amine light stabilizers, ultraviolet absorbers, metal soaps, antistatic agents, antiblocking agents, pigments, flame retardants, fillers, nucleating agents, plasticizers, processing aids, foaming agents, and emulsifiers. The composition (A) may further contain one of these additives, or may contain two or more of them in combination. The content of the above additives in the composition (A) is not particularly limited, but from the viewpoint of processing stability, it is preferably 10 to 75% by mass, more preferably 15 to 70% by mass, and even more preferably 20 to 65% by mass based on the total amount of the composition (A).

Neutralizing agents include, for example, calcium stearate, zinc stearate, magnesium stearate, zinc oxide, synthetic hydrotalcite, natural hydrotalcite, calcium hydroxide, etc.

Examples of the lubricant include oleic acid amide, erucic acid amide, propylene glycol monostearate, stearyl stearate, and sorbitan stearate.

Examples of hindered amine light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (melting point 81-86°C), bis(2,2,6,6-tetramethyl-4-piperidyl)ester, 2,2,6,6-tetramethyl-4-piperidyl methacrylate (melting point 58°C), 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}] (melting point 100-135°C), etc.

Examples of ultraviolet absorbers include 2-hydroxy-4-n-octyloxybenzophenone (melting point 45°C or higher), 2-(2H-benzotriazol-2-yl)-4,6-di-t-pentylphenol (melting point 77°C or higher), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl-]-5-(octyloxy)phenol (melting point 87-89°C), 2-(2-hydroxy-5-methylphenyl)benzotriazole (melting point 127°C), 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole (melting point 137°C), and 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate (melting point 192°C).

Metal soaps include fatty acid metal salts such as calcium stearate.

Examples of antistatic agents include cationic surfactants such as quaternary ammonium salt type cationic surfactants, betaine type amphoteric surfactants, alkyl phosphate type anionic surfactants, primary amine salts, secondary amine salts, tertiary amine salts, quaternary amine salts, and pyridine derivatives; anionic surfactants such as sulfated oils, soaps, sulfated ester oils, sulfated amide oils, sulfated ester salts of olefins, fatty alcohol sulfate salts, alkyl sulfate salts, fatty acid ethyl sulfonates, alkyl naphthalene sulfonates, alkyl benzene sulfonates, succinic acid ester sulfonates, and phosphate salts; nonionic surfactants such as ethylene oxide adducts of partial fatty acid esters of polyhydric alcohols, ethylene oxide adducts of fatty alcohols, ethylene oxide adducts of fatty acids, ethylene oxide adducts of fatty aminos or fatty acid amides, ethylene oxide adducts of alkylphenols, ethylene oxide adducts of partial fatty acid esters of polyhydric alcohols, and polyethylene glycol; and amphoteric surfactants such as carboxylic acid derivatives and imidazoline derivatives.

Antiblocking agents include inorganic antiblocking agents such as aluminum silicate, synthetic silica, natural silica, zeolite, kaolin, and diatomaceous earth, and organic antiblocking agents such as crosslinked polymethyl methacrylic acid.

Examples of pigments include carbon black, titanium oxide, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, perylene or perinine pigments, quinophthalone pigments, diketopyrrolo-pyrrole pigments, dioxazine pigments, disazo condensation pigments, and benzimidazolone pigments.

Flame retardants include decabromobiphenyl, antimony trioxide, phosphorus-based flame retardants, aluminum hydroxide, etc.

Fillers include calcium carbonate, silicates, glass fibers, talc, kaolin, mica, barium sulfate, carbon black, carbon fibers, zeolites, metal powders, metal oxides, etc.

Nucleating agents include sodium salt of α-naphthalenesulfonic acid, magnesium salt of α-naphthalenesulfonic acid, calcium salt of α-naphthalenesulfonic acid, aluminum salt of α-naphthalenesulfonic acid, sodium salt of 8-aminonaphthalenesulfonic acid, sodium salt of benzenesulfonic acid, magnesium salt of benzenesulfonic acid, calcium salt of benzenesulfonic acid, aluminum salt of benzenesulfonic acid, calcium salt of 2,5-dichlorobenzenesulfonic acid, magnesium salt of 2,5-dichlorobenzenesulfonic acid, calcium salt of m-xylenesulfonic acid, magnesium salt of m-xylenesulfonic acid, benzoic acid (melting point 122°C), sodium benzoate (melting point 14 7°C), p-isopropylbenzoic acid, o-t-butylbenzoic acid, p-t-butylbenzoic acid, monophenylacetic acid (melting point 77°C), diphenylacetic acid, Li salt, Al salt, Na salt of diphenylacetic acid, Na salt of diphenylacetic acid, Mg salt of diphenylacetic acid, Ca salt of diphenylacetic acid, Ba salt of diphenylacetic acid, Al salt of diphenylacetic acid, phenyldimethylacetic acid, Li salt of phenyldimethylacetic acid, Na salt of phenyldimethylacetic acid, Mg salt of phenyldimethylacetic acid, Ca salt of phenyldimethylacetic acid, Ba salt of phenyldimethylacetic acid, Mg salt of phthalic acid, succinic acid (melting point 185°C), amber Li salts of succinic acid, Na salt of succinic acid, Mg salt of succinic acid, Ca salt of succinic acid, Ba salt of succinic acid, glutaric acid (melting point 95-99°C), Li salt of glutaric acid, Na salt of glutaric acid, Mg salt of glutaric acid, Ca salt of glutaric acid, Ba salt of glutaric acid, adipic acid (melting point 151-153°C), suberic acid, Li salt of suberic acid, Na salt of suberic acid, Mg salt of suberic acid, Ca salt of suberic acid, Ba salt of suberic acid, sebacic acid, Li salt of sebacic acid, Na salt of sebacic acid, Mg salt of sebacic acid, Ca salt of sebacic acid, Al salt of sebacic acid, diphenylphosphinic acid (melting point 193 to 196°C), Li salt of diphenylphosphinic acid, Na salt of diphenylphosphinic acid, K salt of diphenylphosphinic acid, Ca salt of diphenylphosphinic acid, Mg salt of diphenylphosphinic acid, Al salt of diphenylphosphinic acid, Li salt of 4,4'-dichlorodiphenylphosphinic acid, Na salt of 4,4'-dimethyldiphenylphosphinic acid, dinaphthylphosphinic acid, Li salt of dinaphthylphosphinic acid, Na salt of dinaphthylphosphinic acid, Mg salt of dinaphthylphosphinic acid, Ca salt of dinaphthylphosphinic acid, Al salt of dinaphthylphosphinic acid, etc.

Plasticizers include polyethylene glycol, polypropylene glycol, etc.

Processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, etc.

Examples of the foaming agent include chemical foaming agents and physical foaming agents. Examples of the chemical foaming agent include inorganic compounds and organic compounds. Examples of the inorganic compounds include hydrogen carbonates such as sodium hydrogen carbonate, and ammonium carbonate. Examples of the organic compounds include polycarboxylic acids, azo compounds, sulfonhydrazide compounds, nitroso compounds, p-toluenesulfonylsemicarbazide, and isocyanate compounds. Examples of the physical foaming agent include inert gases, volatile organic compounds such as butane and pentane, and examples of the inert gas include carbon dioxide, nitrogen, argon, neon, and helium.

Emulsifiers include polyoxyethylene sorbitan monolaurate, polyethylene glycol monolaurate, sorbitan tristearate, etc.

In a preferred embodiment of the present invention, composition (A) contains 25 to 100% by mass of antioxidant (a) relative to the total amount of composition (A), and antioxidant (a) contains phenolic antioxidant (1) and phosphorus-based antioxidant (2) and/or sulfur-based antioxidant (3), and the amount of phenolic antioxidant (1) contained in the antioxidant is preferably 2 to 30% by mass relative to the total amount of composition (A), and the amount of phenolic antioxidant (1-1-1) relative to the total amount of phenolic antioxidant (1) is preferably 40 to 100% by mass.

[Additive granules]
The additive granules of the present invention are granules formed from the composition (A). Examples of the shape of the additive granules include "pellets" obtained by granulation using a semi-dry extruder such as a single-screw or multi-screw melt extruder or a disk pelleter, "granules" obtained by stirring and granulating, and "flakes" obtained by granulation using a compression granulator such as a roller compactor. The shape of the additive granules mentioned above means the shape classified according to the definition described in JIS-Z8841 (1993) Section 10, Explanation Table 1, Shape and Name of Granules. The additive granules do not refer to a single granule, but rather to an aggregate of granules. Among the above shapes, "granules" are preferred from the viewpoints of excellent flowability and excellent dispersibility in thermoplastic resins. Granular additive granules can be obtained by any method such as extrusion granulation and stirring granulation, but "granules" obtained by stirring and granulating the composition (A) are more preferred.

The method for producing the additive granules is not particularly limited, but examples include a method in which composition (A) is stirred and granulated or extruded at an appropriate temperature range, for example, 40°C to 80°C, preferably 40°C to 70°C, and particularly preferably 40°C to 60°C.

Examples of equipment used for stirring and granulating include high-speed rotating equipment such as a Henschel mixer, a super mixer, and a high-speed mixer, stirring and mixing granulators such as a vertical granulator, and rolling fluidized coating equipment. Granulated materials may also be produced by the manufacturing method described in JP 2010-254958 A.

As an example of the stirring granulation method, the raw materials constituting the composition (A) are charged into a mixer such as a Henschel mixer and then stirred and mixed at high speed. As a method for setting the temperature within the above range, for example, a method of heating the Henschel mixer by attaching a hot water jacket to it, or a method of increasing the temperature by utilizing the shear heat generated by high-speed stirring, etc. can be mentioned.

The size of the additive granules is not particularly limited, but for example, when produced by stirring granulation, the median diameter (mass basis) is preferably 0.1 to 7 mm, more preferably 0.15 to 6 mm, even more preferably 0.18 to 6 mm, and even more preferably 0.20 to 6 mm. The median diameter (mass basis) is determined by mechanically sieving approximately 100 g of sample using a low-tap shaker (e.g., low-tap shaker RL-1, Kagaku Kyoeisha) for 15 minutes, with a shaking speed of 290 rpm/60 Hz, a swing width of 25 mm, and a stroke rate of 156 tpm/60 Hz.

As a method for producing an additive granule having the above-mentioned median diameter (by mass), for example, a method using an agitator granulator having an agitator blade and an internal clearance between the tip of the agitator blade and the wall surface of the agitator blade is adjusted to 30 mm or less. The additive granule having the above-mentioned median diameter (by mass) is preferably in the form of a granule.

Examples of equipment used for extrusion granulation include single-screw or multi-screw melt extruders, and semi-dry extruders such as disc pelleters.

For example, the extrusion granulation method involves mixing the raw materials constituting composition (A) in a mixer such as a Henschel mixer or a super mixer to prepare a mixture, feeding the mixture from a hopper or the like into an extruder, and adjusting the material temperature in the extruder to 40°C to 80°C using the shear heat generation or heating equipment of the extruder, which allows easy extrusion and gives cylindrical granules. The extruded cylindrical granules can be cut to an appropriate length with a cutter or the like to give pellet-shaped additive granules. By adjusting the die aperture, extrusion speed, and cutting speed, additive granules of any size can be produced, but from the viewpoint of dispersibility, a diameter of 2 to 5 mm and a length of 2 to 5 mm are preferable.

The additive granules of the present invention contain 40 to 100% by mass of phenolic antioxidant (1-1-1) relative to the total amount of phenolic antioxidant (1). The ratio of the amount of phenolic antioxidant (1-1-1) relative to the total amount of phenolic antioxidant (1) contained in the additive granules may be calculated, for example, from the charge ratio when producing the additive granules, or the amount of phenolic antioxidant (1) contained in the additive granules may be identified and quantified by HPLC, and the amount of phenolic antioxidant (1-1-1) may be calculated from the endothermic heat at the time of melting at around 124 to 127°C by DSC, and the ratio may be calculated from these amounts.

The additive granules according to one embodiment of the present invention are used by being blended with, for example, plastics, such as thermoplastic resins. The blending ratio of the additive granules to the plastics can be, for example, 0.005 to 10 parts by mass of the additive granules per 100 parts by mass of the plastic, preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass. The present invention also provides a method for producing a plastic composition by blending the additive granules of the present invention with a plastic, preferably 0.005 to 10 parts by mass of the additive granules of the present invention with 100 parts by mass of the plastic, and the plastic composition. The plastic composition obtained by the above-mentioned manufacturing method has the advantage that, for example, there is little variation in the amount of additive added and the additive is uniformly dispersed, since the additive granules having high fluidity are added to the plastic composition. According to the present invention, a method for stabilizing a plastic can also be provided, which includes a step of blending 0.005 to 10 parts by mass of the additive granules of the present invention with 100 parts by mass of the plastic.

The plastic to be mixed with the additive granules is preferably a thermoplastic resin. There are no particular limitations on the thermoplastic resin as long as it is a commercially available resin, but examples of the thermoplastic resin include polypropylene resins such as ethylene-propylene copolymers, polyethylene resins (high density polyethylene (HD-PE), low density polyethylene (LD-PE), linear low density polyethylene (LLDPE), etc.), methylpentene polymers, ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, polystyrenes (poly(p-methylstyrene), poly(α-methylstyrene), etc., acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, special acrylic rubber-acrylonitrile-styrene copolymers, acrylonitrile-chlorinated polyethylene-styrene copolymers, styrene-butadiene copolymers, etc.), chlorinated polyethylene, polychloroprene, chlorinated rubber, polyvinyl chloride, polychlorinated Examples of suitable resins include vinylidene, methacrylic resin, ethylene-vinyl alcohol copolymer, fluororesin, polyacetal, grafted polyphenylene ether resin, polyphenylene sulfide resin, polyurethane, polyamide, polyester resin (e.g., polyethylene terephthalate, polybutylene terephthalate, etc.), polycarbonate, polyacrylate, polysulfone, polyether ether ketone, polyether sulfone, aromatic polyester resin, diallyl phthalate prepolymer, silicone resin, 1,2-polybutadiene, polyisoprene, butadiene/acrylonitrile copolymer, ethylene-methyl methacrylate copolymer, etc., and from the viewpoint of good moldability, polyolefin resins such as polyethylene resins and polypropylene resins, and polystyrene resins are preferred, with polyolefin resins being more preferred.

Here, polypropylene-based resin means a polyolefin-based resin containing structural units derived from propylene, and specific examples include crystalline propylene homopolymer, propylene-ethylene random copolymer, propylene-α-olefin random copolymer, propylene-ethylene-α-olefin copolymer, polypropylene-based block copolymers consisting of a propylene homopolymer component or a copolymer component mainly consisting of propylene, and a copolymer component of propylene and ethylene and/or α-olefin. When a polypropylene-based resin is used as the thermoplastic resin, one type of polypropylene-based resin may be used, or two or more types may be blended together.

Examples of α-olefins include α-olefins having 4 to 12 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene, with 1-butene, 1-hexene, and 1-octene being preferred.

Examples of propylene-α-olefin random copolymers include propylene-1-butene random copolymers, propylene-1-hexene random copolymers, and propylene-1-octene random copolymers.

Examples of propylene-ethylene-α-olefin copolymers include propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, and propylene-ethylene-1-octene copolymer.

In the polypropylene block copolymer consisting of a propylene homopolymer component or a copolymer component consisting mainly of propylene, and a copolymer component consisting of propylene and ethylene and/or α-olefin, examples of the copolymer component consisting mainly of propylene include a propylene-ethylene copolymer component, a propylene-1-butene copolymer component, and a propylene-1-hexene copolymer component, and examples of the copolymer component consisting of propylene and ethylene and/or α-olefin include a propylene-ethylene copolymer component, a propylene-ethylene-1-butene copolymer component, a propylene-ethylene-1-hexene copolymer component, a propylene-ethylene-1-octene copolymer component, a propylene-1-butene copolymer component, a propylene-1-hexene copolymer component, and a propylene-1-octene copolymer component. The content of ethylene and/or an α-olefin having 4 to 12 carbon atoms in the copolymer component consisting of propylene and ethylene and/or α-olefin is, for example, 0.01 to 20% by weight.

In addition, examples of polypropylene block copolymers consisting of a propylene homopolymer component or a copolymer component mainly consisting of propylene and a copolymer component of propylene and ethylene and/or α-olefin include propylene-ethylene block copolymers, (propylene)-(propylene-ethylene) block copolymers, (propylene)-(propylene-ethylene-1-butene) block copolymers, (propylene)-(propylene-ethylene-1-hexene) block copolymers, (propylene)-(propylene-1-butene) block copolymers, (propylene)-(propylene-1-hexene) block copolymers, (propylene-ethylene)-(propylene-ethylene-1-butene) block copolymers. copolymers, (propylene-ethylene)-(propylene-ethylene-1-hexene) block copolymers, (propylene-ethylene)-(propylene-1-butene) block copolymers, (propylene-ethylene)-(propylene-1-hexene) block copolymers, (propylene-1-butene)-(propylene-ethylene) block copolymers, (propylene-1-butene)-(propylene-ethylene-1-butene) block copolymers, (propylene-1-butene)-(propylene-ethylene-1-hexene) block copolymers, (propylene-1-butene)-(propylene-1-butene) block copolymers, (propylene-1-butene)-(propylene-ethylene-1-hexene) block copolymers, (propylene-1-butene)-(propylene-1-butene) block copolymers, (propylene-1-butene)-(propylene-1-butene) block copolymers, (propylene-1-butene)-(propylene-1-hexene) block copolymers, etc.

When a polypropylene-based resin is used as the thermoplastic resin, a crystalline propylene homopolymer, a polypropylene-based block copolymer consisting of a propylene homopolymer component or a copolymer component mainly consisting of propylene, and a copolymer component of propylene and ethylene and/or an α-olefin having 4 to 12 carbon atoms is preferably used, and more preferably a polypropylene-based block copolymer consisting of a propylene homopolymer component or a copolymer component mainly consisting of propylene, and a copolymer component of propylene and ethylene and/or an α-olefin having 4 to 12 carbon atoms is used.

Methods for incorporating additive granules into plastics include, for example, a method in which the additive granules and plastic are mixed and then melt-kneaded using a single-screw or multi-screw extruder, and a method in which the additive granules are added by feeding them into a solution obtained after polymerizing a thermoplastic resin. The thermoplastic resin obtained in this way can be processed into products such as films, molding materials, and pipes.

The additive granules of the present invention have good fluidity, so when blended with plastics such as thermoplastic resins, they are easy to handle and are less likely to vary in the amount added, making it possible to produce a highly uniform plastic composition. In addition, when the additive granules of the present invention are blended with plastics, the effects of the additive granules are uniformly exerted, and a thermoplastic resin composition with excellent heat coloring resistance can be obtained.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

The components used in the examples and comparative examples are listed below.
Compound (1-1-1): 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, which has a crystal structure that exhibits sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6° by X-ray diffraction measurement using X-rays of Cu-Kα wavelength. (The results of the X-ray diffraction measurement are shown in FIG. 1. Note that the left end of the horizontal axis in FIG. 1 and FIG. 2 is 4°.)
Compound (1-1-2): 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, which has a crystal structure that shows a sharp X-ray diffraction peak at a diffraction angle 2θ = 7.9° by X-ray diffraction measurement using X-rays of Cu-Kα wavelength (the result of the X-ray diffraction measurement is shown in Figure 2).
Compound (2-1): Tris(2,4-di-t-butylphenyl)phosphite "Irgafos 168 (registered trademark)" (manufactured by BASF)
Compound (3-1): 3,3'-thiodipropionic acid di-n-tetradecyl ester "Sumilizer TPM (registered trademark)" (manufactured by Sumitomo Chemical)

(Example 1: Production of additive granule A-1)
Into a 10 L high-speed mixer (manufactured by Fukae Powtec Co., Ltd.: model number FS-GS-10J), 187.5 g of compound (1-1-1), 750.0 g of compound (2-1), and 562.5 g of compound (3-1) were charged. After charging, the stirring tank equipped with the high-speed mixer was heated by passing hot water at 50 ° C. through the jacket of the high-speed mixer. Thereafter, the rotation speed of the stirring blade was set to 450 rpm, and the rotation speed of the chopper blade was set to 2000 rpm, and the compounds were mixed. Stirring was stopped when the agitator current reached 4.7 A, and additive granules A-1 having a median diameter (mass basis) of 241 μm was obtained.

(Comparative Example 2: Production of additive granule A-2)
Additive granule A-2 was obtained in the same manner as in the production of additive granule A-1, except that compound (1-1-2) was used instead of compound (1-1-1) used in the production of additive granule A-1.

(Examples 2 to 3, Comparative Example 1)
A total of 80.0 g of additive granules A-1 and/or additive granules A-2 in the proportions shown in Table 1 were placed in a 20 L plastic bag and mixed uniformly to obtain additive granules B-1 to B-3.

(Liquidity)
80.0 g of the obtained additive granules of Examples 1 to 3 and Comparative Examples 1 and 2 were each placed into a funnel (with a stopper) with an opening diameter of 95 mm and an outer leg diameter of 20 mm. The fluidity of the additive granules in their initial state when the stopper was removed was evaluated. After evaluating the initial state, the additive granules were stored in a thermo-hygrostat at a temperature of 35°C and a humidity of 80% RH for 7 days, and then the fluidity was evaluated in the same manner. The results are shown in Table 1.
Evaluation criteria for fluidity: ○: The entire amount flows down.
×: The entire amount did not flow down due to bridging phenomenon.

(Median diameter based on mass)
Each of the additive granules A-1 and A-2 was used as a measurement sample, and 100 g of the sample was mechanically sieved using a low tap shaker RL-1 (Kagaku Kyoeisha) under the conditions of a sieving time of 15 minutes, a shaking speed of 290 rpm/60 Hz, a swing width of 25 mm, and a stroke rate of 156 tpm/60 Hz to determine the median diameter based on mass. The median diameters of the additive granules A-1 and A-2 were within the range of 0.1 to 7 mm.

The components used in the production examples are listed below.
Compound (4-1): Calcium stearate "Calcium Stearate WLC (registered trademark)" (manufactured by Fac
Compound (5-1): Sodium benzoate "Sodium Benzoate 20M (registered trademark)" (manufactured by BASF)
Compound (6-1): Hydrotalcite "DHT-4C (registered trademark)" (manufactured by Kyowa Chemical Industry Co., Ltd.)
Compound (7-1): Talc "Micron White 5000S (registered trademark)" (manufactured by Hayashi Kasei)
Compound (8-1): Oleic acid amide "Kemamide VO (registered trademark)" (manufactured by PMC)

(Production Example: Additive Granule A-3)
A 100L high-speed mixer (manufactured by Fukae Powtec Co., Ltd.: model number FS-100) is charged with raw materials (total 15 kg) consisting of 8.9 parts by weight of compound (1-1-1), 35.7 parts by weight of compound (2-1), 26.8 parts by weight of compound (3-1), 25.0 parts by weight of compound (5-1), and 3.6 parts by weight of compound (6-1). The high-speed mixer is heated by passing hot water at 50°C through the jacket of the high-speed mixer. The rotation speed of the stirring blade inside the stirring tank of the high-speed mixer is set to 165 rpm (6 m/s as the blade tip speed) and the rotation speed of the chopper is set to 1500 rpm (10 m/s as the blade tip speed), and the high-speed mixer is operated for about 20 minutes while maintaining this state. In this way, additive granules A-3, which are obtained by stirring and granulating the mixture consisting of the raw materials, are obtained.

(Production Example: Additive Granule A-4)
Additive granule A-4 was obtained in the same manner as additive granule A-3, except that compound (1-1-2) was used instead of compound (1-1-1) used in additive granule A-3.

(Production Example: Additive Granule A-5)
A 100L high-speed mixer (manufactured by Fukae Powtec Co., Ltd.: model number FS-100) is charged with raw materials (total 15 kg) consisting of 9.6 parts by weight of compound (1-1-1), 38.2 parts by weight of compound (2-1), 29.1 parts by weight of compound (3-1), 19.3 parts by weight of compound (4-1), and 3.8 parts by weight of compound (7-1). The high-speed mixer is heated by passing hot water at 50°C through the jacket of the high-speed mixer. The rotation speed of the stirring blade inside the stirring tank of the high-speed mixer is set to 165 rpm (6 m/s as the blade tip speed) and the rotation speed of the chopper is set to 1500 rpm (10 m/s as the blade tip speed), and the high-speed mixer is operated for about 1 minute and 20 seconds while maintaining this state. In this way, additive granules A-5, which are obtained by stirring and granulating the mixture consisting of the raw materials, are obtained.

(Production Example: Additive Granule A-6)
Additive granule A-6 is obtained in the same manner as additive granule A-5, except that compound (1-1-2) is used instead of compound (1-1-1) used in additive granule A-5.

(Production Example: Additive Granule A-7)
A 100L high-speed mixer (manufactured by Fukae Powtec Co., Ltd.: model number FS-100) is charged with raw materials (total 15 kg) consisting of 3.9 parts by weight of compound (1-1-1), 15.4 parts by weight of compound (2-1), 11.5 parts by weight of compound (3-1), 7.7 parts by weight of compound (4-1), 46.1 parts by weight of compound (7-1), and 15.4 parts by weight of compound (8-1). The high-speed mixer is heated by passing hot water at 50°C through the jacket of the high-speed mixer. The rotation speed of the stirring blade inside the stirring tank of the high-speed mixer is set to 165 rpm (6 m/s as the blade tip speed) and the rotation speed of the chopper is set to 1500 rpm (10 m/s as the blade tip speed), and the high-speed mixer is operated for about 40 minutes while maintaining this state. In this way, additive granules A-7, which is obtained by stirring and granulating the mixture consisting of the raw materials, is obtained.

(Production Example: Additive Granule A-8)
Additive granule A-8 was obtained in the same manner as additive granule A-7, except that compound (1-1-2) was used instead of compound (1-1-1) used in additive granule A-7.

(Production Example: Additive Granule A-9)
Raw materials consisting of 8.9 parts by weight of compound (1-1-1), 35.7 parts by weight of compound (2-1), 26.8 parts by weight of compound (3-1), 25.0 parts by weight of compound (5-1), and 3.6 parts by weight of compound (6-1) are mixed in a 100 L high-speed mixer (manufactured by Fukae Powtec Co., Ltd.: model number FS-100) using a Henschel mixer. Then, this mixture is put into a disk pelleter (manufactured by Dalton Co., Ltd.: model number F-5) and operated. The pellet-shaped additive granules A-9 are obtained by extruding from a disk die under a roller and cutting immediately thereafter.

(Production Example: Additive Granule A-10)
Additive granule A-10 is obtained in the same manner as additive granule A-9, except that compound (1-1-2) is used instead of compound (1-1-1) used in additive granule A-9.

(Production Example: Additive Granule A-11)
Raw materials consisting of 9.6 parts by weight of compound (1-1-1), 38.2 parts by weight of compound (2-1), 29.1 parts by weight of compound (3-1), 19.3 parts by weight of compound (4-1), and 3.8 parts by weight of compound (7-1) are mixed in a 100 L high-speed mixer (manufactured by Fukae Powtec Co., Ltd.: model number FS-100) using a Henschel mixer. Then, this mixture is put into a disk pelleter (manufactured by Dalton Co., Ltd.: model number F-5) and operated. The pellet-shaped additive granules A-11 are obtained by extruding from a disk die under a roller and cutting immediately thereafter.

(Production Example: Additive Granule A-12)
Additive granule A-12 is obtained in the same manner as additive granule A-11, except that compound (1-1-2) is used instead of compound (1-1-1) used in additive granule A-11.

(Production Example: Additive Granule A-13)
The raw materials consisting of 3.9 parts by weight of compound (1-1-1), 15.4 parts by weight of compound (2-1), 11.5 parts by weight of compound (3-1), 7.7 parts by weight of compound (4-1), 46.1 parts by weight of compound (7-1), and 15.4 parts by weight of compound (8-1) are mixed using a Henschel mixer. Then, this mixture is put into a disk pelleter (manufactured by Dalton Co., Ltd.: model number F-5) and operated. The pellet-shaped additive granule A-13 is obtained by extruding from a disk die under a roller and cutting immediately thereafter.

(Production Example: Additive Granule A-14)
Additive granule A-14 is obtained in the same manner as additive granule A-13, except that compound (1-1-2) is used instead of compound (1-1-1) used in additive granule A-13.

The additive granules A-3, A-5, A-7, A-9, A-11 and A-13 obtained in the above manufacturing examples are considered to have the same initial and seven-day fluidity as Example 1. In addition, the additive granules A-4, A-6, A-8, A-10, A-12 and A-14 obtained in the above manufacturing examples are considered to have the same initial and seven-day fluidity as Comparative Example 2.

The present invention provides an additive granule with excellent fluidity.

Claims (14)

An additive granule formed from a composition (A) containing an antioxidant (a) containing a phenolic antioxidant (1), the additive granule containing 40 to 100 mass% of the phenolic antioxidant (1-1-1), which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane having a crystal structure that shows sharp X-ray diffraction peaks at diffraction angles 2θ=4.2° and 2θ=10.6° when measured using X-rays with a Cu-Kα wavelength. The additive granule according to claim 1, wherein the content of the phenolic antioxidant (1-1-1) is 40 to 100% by mass relative to the total amount of the phenolic antioxidant (1-1), which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, contained in the phenolic antioxidant (1). The additive granule according to claim 1, wherein the ratio of the amount of the phenolic antioxidant (1-1-1) to the amount of the phenolic antioxidant (1-1-2) which is 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane having a crystal structure that shows a sharp X-ray diffraction peak at a diffraction angle 2θ=7.9° in X-ray diffraction measurement using X-rays of Cu-Kα wavelength is (1-1-1):(1-1-2)=100:0 to 40:60. The additive granule according to claim 1, wherein the amount of the phenolic antioxidant (1) contained in the composition (A) is 2 to 30 mass% based on the total amount of the composition (A). The additive granule according to claim 1, wherein the amount of antioxidant (a) contained in composition (A) is 25 to 100 mass% based on the total amount of composition (A). The additive granule according to claim 1, wherein the antioxidant (a) further comprises a phosphorus-based antioxidant (2) and/or a sulfur-based antioxidant (3). The additive granule according to claim 6, wherein the total amount of the phenol-based antioxidant (1), the phosphorus-based antioxidant (2) and/or the sulfur-based antioxidant (3) contained in the composition (A) is 25 to 100% by mass based on the total amount of the composition (A). The additive granule according to claim 6, wherein the amount of the phenol-based antioxidant (1) is 5 to 30 mass% and the total amount of the phosphorus-based antioxidant (2) and/or the sulfur-based antioxidant (3) is 70 to 95 mass% relative to the total amount of the antioxidant (a). The additive granule according to claim 6, wherein the amount of the phenol-based antioxidant (1) is 10-15 mass%, the amount of the phosphorus-based antioxidant (2) is 48-53 mass%, and the amount of the sulfur-based antioxidant (3) is 35-40 mass%, relative to the total amount of the antioxidant (a). The additive granule according to claim 1, wherein composition (A) further comprises at least one additive selected from the group consisting of neutralizing agents, lubricants, hindered amine light stabilizers, ultraviolet absorbers, metal soaps, antistatic agents, antiblocking agents, pigments, flame retardants, fillers, nucleating agents, plasticizers, processing aids, foaming agents, and emulsifiers. The additive granule according to claim 1, wherein the additive granule has a median diameter (by mass) of 0.1 to 7 mm. A method for producing a plastic composition, comprising the step of blending 0.005 to 10 parts by mass of the additive granules according to any one of claims 1 to 10 with respect to 100 parts by mass of plastic. The method for producing a plastic composition according to claim 12, wherein the plastic is a thermoplastic resin. The method for producing a plastic composition according to claim 12, wherein the plastic is a polyolefin resin.

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