JPH03100092A - Reactive antioxidant and polymer composition containing same - Google Patents

Abstract

PURPOSE:To obtain a reactive antioxidant having a sufficient antioxidizing effect and excellent oil and blooming resistances by using a specified phenolic compound as the effective component. CONSTITUTION:A reactive antioxidant is obtained by using a phenolic compound of formula I (wherein R1 and R2 are each 1-4C alkyl; R3 and R4 are each H or 1-4C alkyl; R5 is H, 1-12C alkyl or 6-12C aryl; (l) is 0 to 3; (m) is 1 to 15 and (n) is 0 to 15, provided that (m+n) is 5 to 30) as the effective component. The antioxidant is incorporated in an amount of 0.1-20wt.% into a polymer to crosslink the phenolic compound with the polymer, giving a polymer composition. Because of the excellent antioxidizing effect and extraction and blooming resistances, this composition is effectively used as a material of which long-term heat resistance is required and a material of which extraction resistance is required. The compound of formula I can be obtained by reacting an alcohol of formula II (wherein R1, R2, and (l) are as defined above) with an unsaturated fatty acid chloride of formula III (wherein R3, R4, R5, (m), and (n) are as defined above).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antioxidant having a double bond in its molecule that can be crosslinked with a polymer, and a polymer composition comprising the same.

[Prior Art] In order to prevent deterioration of polymeric materials due to oxidation, amine-based, phenol-based, and other antioxidants have been used. Amine-based antioxidants are mostly polluting, so their uses are limited, and recently phenol-based antioxidants have been widely used.

Examples of phenolic antioxidants include n-tadecyl-3-(4'-hydroxy-3').

5°-di-t-butylphenyl) propionate (trade name: Irganox 1076,
Ciba Geigy) and tetrakis-[methylene-3-(
3°, 5°-di-t-butyl-4′-hydroxyphenyl)propionate comethane (trade name: Nilganox 101O, manufactured by Ciba Geigy) and the like are used.

However, these antioxidants are merely physically mixed into the formulation by the kneading operation, so when the formulation comes into contact with organic solvents or water, the antioxidants are easily extracted and their The effect is extremely reduced. Furthermore, when used for a long period of time, the antioxidant precipitates on the surface of the product, which is called blooming, which reduces the antioxidant effect and also causes contamination of the surrounding area.

To solve these problems, reactive antioxidants having double bonds in their molecules that can be crosslinked with polymers have recently been used. Typical examples of such antioxidants are
For example, a compound represented by the formula: or the formula; ("Antioxidant Handbook")
, 1st edition, pp. 3-4, Taiseisha).

Further, JP-A-54-153896 discloses a method for producing a copolymer containing a phenolic reactive anti-aging agent.

[Problems to be Solved by the Invention] Conventionally, this type of reactive antioxidant has excellent extraction resistance, but has the disadvantage that a sufficient antioxidant effect cannot be obtained. The present invention aims to provide a polymer composition containing an antioxidant that has a sufficient antioxidant effect and is excellent in extraction resistance and blooming resistance.

[Means for Solving the Problem] The above problem is solved by the formula: [wherein R1 and R2 are an alkyl group having 1 to 4 carbon atoms,
R3 and R2 are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R6 is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, Q is a number of 0 to 3, and m is 1 ~15 numbers, n represents a number from 0 to 15, m+
The total number of H is 5 to 30. This problem can be solved by using a phenolic compound as an antioxidant.

The phenolic compound has the formula: [wherein R1, R3 and g have the same meanings as above. [R3, R4 and R6, m and n have the same meanings as above, and the sum of m+H is 5 to 30. ] It is obtained by reacting the unsaturated fatty acid chloride shown.

In the above formula, R3 and R2 are alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and t-butyl groups, preferably monobutyl group. Also, R3 and R
4 may also be an alkyl group having 1 to 4 carbon atoms. In addition,
R3 and R4 may be hydrogen atoms. R5 is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

The alcohols of formula (11) and used in the preparation of the phenolic compounds according to the invention are known compounds, for example 3,5-di-butyl-4-hydroxybenzyl alcohol, 3,5-di-butyl-4-hydroxybenzyl alcohol, 3,5-di-butyl-4-hydroxybenzyl alcohol, Examples include butyl-4-hydroxyphenol, 3.5-di-t-butyl-4-hydroxyphenethyl alcohol, and the like.

Acid chloride represented by formula (1) and used for the preparation of phenolic compounds is also a known compound.

The number of carbon atoms contained in the main chain is preferably 5 or more; if the number is smaller than this, a sufficient antioxidant effect cannot be obtained. Examples of such acid chlorides include:
Examples include oleic acid chloride, erucyl chloride, linoleic acid chloride, and linoleic acid chloride.

Typical examples of the phenolic compounds obtained in this way are 3.5-di-t-butyl-4-hydroxybenzyl alcohol, 3.5-di-t-butyl-4-hydroxybenzyl alcohol, rate, etc.

Phenolic compound obtained as described above 0.1~
A polymer composition is obtained by blending 20% by weight, preferably 0.5 to 10% by weight, into a polymeric material as an antioxidant. The type of polymeric material is not particularly limited, and any polymer that can react with the phenolic compound may be used.

Typical examples include polyolefin, polyester elastomer, polyolefin elastomer, polyurethane, and ethylene propylene rubber. Further, such polymer compositions may contain appropriate amounts of commonly used compounding agents such as stabilizers, lubricants, fillers, reinforcing agents, flame retardants, and the like.

The polymer composition thus obtained is reacted with a reactive antioxidant using known methods such as irradiation with radiation and/or a chemical crosslinking agent or a combination of both. This operation can be carried out by methods and devices known per se and commonly used. The radiation dose is 0.1 to 100 Mrad (1 to 1000 KGy),
Preferably it is 1 to 50 Mrad (10 to 500 KGy). Chemical crosslinking agents may also be known crosslinking agents commonly used for crosslinking polymers. For example, organic peroxide-based, polyamine-based, sulfur-based, and oxime-based crosslinking agents may be used, but organic peroxide-based crosslinking agents are preferred.

[Function] In the phenolic antioxidant, it is the hydroxyl group bonded to the benzene ring that has the antioxidant function, and the radicals generated by oxidation are captured and stabilized by the hydroxyl group, thereby exhibiting the antioxidant effect. In the reactive antioxidant used in the present invention, it is the hydroxyl group bonded to the benzene ring that has the antioxidant function, but the antioxidant effect varies greatly depending on the structure of the molecule. Conventional reactive antioxidants did not have sufficient antioxidant effects, but in the present invention, by increasing the molecular length of unsaturated fatty acids in phenolic compounds to a certain extent, reactive antioxidants with sufficient antioxidant effects have been developed. It was discovered that it can be used as a drug. The reason why the antioxidant effect improves as the molecular length increases is unknown, but antioxidants with long molecular lengths can move around in the composition over a relatively wide range even when bonded to a polymer, so the antioxidant effect increases by that amount. It is speculated that this is because there is an increased opportunity to capture radicals that cause deterioration.

In addition, this reactive antioxidant has a double bond in its molecule, and the double bond reacts and bonds with the polymer by known crosslinking methods such as radiation irradiation or chemical crosslinking agents, so it is resistant to Excellent extractability and blooming resistance.

[Example] The present invention will be explained in more detail with reference to the following example. Note that these Examples do not limit the present invention.

Preparation of reactive antioxidant (a) 150 g of 3.5-di-t-butyl-4-hydroxybenzyl alcohol was introduced into a reaction vessel, and then 230 g of oleic acid chloride was introduced and heated to 60°C for 1 hour. Made it react. The obtained reaction product was washed with hydrochloric acid, dehydrated with sodium sulfate, and purified by drying under reduced pressure for 30 minutes to obtain 300 g of reactive antioxidant A.

(b) According to the procedure shown in the previous section (a), 3,5-di-butyl-4-hydroxybenzyl alcohol 289
and linoleic acid chloride 709 were reacted at 60° C. for 1 hour to obtain reactive antioxidant B929.

(c) 3,5-di-1-butyl-4-hydroxyphenethyl alcohol 25 according to the procedure shown in the previous section (a).
g and 63 g of lyrinic acid chloride were reacted at 60° C. for 1 hour to obtain reactive antioxidant C809.

Example 1 Low density polyethylene (melt index: 1°5) 1
1 part by weight of the reactive antioxidant A previously obtained was blended with 00 parts by weight and kneaded with rolls at 120°C to prepare a polyethylene blend. The obtained mixture was pressed under the conditions of 130° C.XIO minutes to produce a sheet having a thickness of 11. Accelerating voltage I
This polyethylene formulation was crosslinked using a MeV bump graph electron beam accelerator. Electron beam irradiation amount is 25M
It was set as rad. The following test was conducted using the obtained sample.

Example 2 Reactive antioxidant A2 in 100 parts by weight of ethylene vinyl acetate copolymer (EVA, melt index: 0,7)
Parts by weight and 1 part by weight of dicumyl peroxide as a crosslinking agent were blended and rolled at 120°C to prepare an EVA blend. The EVA formulation was crosslinked using a press at 160°C for 130 minutes. The following test was conducted using the obtained sample.

Example 3 An EVA formulation was prepared by repeating Example 1, except using 100 parts by weight of EVA and 2 parts by weight of reactive antioxidant B, and the resulting formulation was crosslinked by electron beam irradiation. The electron beam irradiation amount was 15 Mrad. The following test was conducted using the obtained sample.

EE by repeating Example 1 except using 100 parts by weight of K Kagosakudo ethylene acrylate copolymer (EEA, melt index: 2.0) and 2 parts by weight of reactive antioxidant B.
A formulation was prepared and the resulting formulation was crosslinked by electron beam irradiation. The electron beam irradiation amount was 25 Mrad. The following test was conducted using the obtained sample.

Example 5 04 parts by weight of a reactive antioxidant and 711 parts by weight of dicumyl bicarbonate as a crosslinking agent were blended with 00 parts by weight of EEA, and the mixture was kneaded with a roll to prepare an EEA blend. The resulting formulation was crosslinked by electron beam irradiation according to the procedure set forth in Example 1. The electron beam irradiation amount was 15 Mrad. The following test was conducted using the obtained sample.

Comparative Examples 1 to 4 As comparative examples, (3,5-di-t-butyl-4-hydroxybenzyl)acrylate and n-tadecyl-
3-(4'-Hydroxy-3',5'-di-t-butylphenyl)propionate (product name Nylganox l
O7B, manufactured by Ciba Geigy), each formulation was prepared by roll kneading according to the formulation system shown in Table 1. In Comparative Examples 1, 3, and 4, the formulations obtained by irradiating electron beams were crosslinked according to the procedure shown in Example 1 (electron beam irradiation amount, 15 to 25 Mrad). Further, in Comparative Example 2, the resulting compound was crosslinked using a press at 160° C. for 30 minutes. The following tests were conducted using the samples thus obtained.

In order to evaluate the effect of the antioxidant contained in the aging test sample, an aging test was conducted according to JISK7212. Thickness lax specified by JISK7113 from each sample
A JIS No. 2 test piece was used as a punching test sample.

The tensile strength and elongation of the sample before aging were measured using a tensile tester at a tensile rate of 500xx/min, and of the sample after aging by heating at 160° C. for 168 hours using a thermal oven.

In addition, in Table 1, the tensile strength and elongation after aging are expressed by the formula: % formula % () [where Xa represents the tensile strength or elongation after aging, and Xo represents the tensile strength or elongation before aging. The tensile strength and elongation retention before aging are shown in .

2. Bloom test A bloom test was conducted to evaluate the bloom property of the polymer composition. In order to determine the presence or absence of antioxidant bloom, a black sheet was prepared by adding 2 parts of carbon black and left at room temperature for one month. The appearance of antioxidant bloom was visually evaluated.

The results are shown in Table 1.

As can be seen from Table 1, the polymer composition crosslinked with the reactive antioxidant of the present invention exhibits good aging resistance and does not bloom.

[Effects of the Invention] According to the present invention, the reactive antioxidant synthesized from unsaturated fatty acid chloride whose main chain has a certain number of carbon atoms is extremely superior to conventional reactive antioxidants. Demonstrates antioxidant effect. Furthermore, since this antioxidant has reactivity and can crosslink with polymers, it has excellent blooming resistance and extraction resistance. That is, a polymer composition comprising an appropriate amount of such a reactive antioxidant,
Since it has excellent antioxidant effects, extraction resistance, and blooming resistance, it is effective when used in materials that require long-term heat resistance or extraction resistance.

Claims (1)

[Claims] 1. Formulas: ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, R_1 and R_2 are alkyl groups having 1 to 4 carbon atoms, and R_3 and R_4 are hydrogen atoms or 1 carbon number. ~4
an alkyl group, R_5 is a hydrogen atom or has 1 to 12 carbon atoms
an alkyl group or an aryl group having 6 to 12 carbon atoms, l
represents a number from 0 to 3, m represents a number from 1 to 15, n represents a number from 0 to 15, and the sum of m+n is from 5 to 30. ] A reactive antioxidant consisting of a phenolic compound represented by: 2. A polymer composition comprising 0.1 to 20% by weight of the phenolic compound according to claim 1 as an antioxidant, the phenolic compound being crosslinked with a polymer.