JPH03182588A - Antioxidant and polymer composition containing it - Google Patents

Abstract

PURPOSE:To obtain an antioxidant improved in antioxidizing effect and blooming resistance by forming a compound having a specified structural formula. CONSTITUTION:A phosphorus trichloride and an unsaturated alcohol, if necessary, mixed with a saturated alcohol or phenol derivative are reacted in a solvent in the presence of a tertiary amine, and then the amine is removed. The obtained reaction product is concentrated to give an antioxidant comprising a phosphorus compound of the formula (wherein R1, R2, and R3 are each an organic group, provided that at least one of them is a group having C-C unsaturated bonds). 0.1-20wt.% antioxidant thus obtained is incorporated into a polymeric material to give a polymeric composition. This composition is molded and the antioxidant is crosslinked to a polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an antioxidant crosslinkable 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, sulfur-containing, and phosphorus-containing antioxidants have been used.

Amine-based antioxidants are mostly polluting, so their uses are limited, and recently phenolic antioxidants, which are non-staining, have been widely used.

Among phenolic antioxidants, hindered phenols are particularly important, such as n-octadecyl-3°,
Representative examples include 5°-di-t-butylphenylpropionate and tetrakis-[methylene-3-(3',5°-di-t-butyl-4°-hydroxyphenyl)propionate comethane.

In addition, for example, dilauryl diodipropionate and 2
- Sulfur-containing antioxidants such as mercaptobenzimidazole, phosphorus-containing antioxidants such as triphenyl phosphite and trinonylphenyl phosphite are known.

Sulfur-containing and phosphorus-containing antioxidants are rarely used alone, but are often used in combination with phenolic antioxidants. In other words, by supplementing the radical species generated during the oxidation process of polymeric materials with a phenolic antioxidant and decomposing the peroxides generated in the process with a sulfur-containing or phosphorus-containing antioxidant, synergistic effects can be achieved. Techniques are used to increase the antioxidant effect.

However, these antioxidants are generally used by simply being physically dispersed in the formulation by a kneading operation, and therefore, oxidation can occur over long periods of use, especially under high temperature conditions. The drawback is that the inhibitor migrates to the product surface, precipitates (so-called blooming), and further evaporates and evaporates, resulting in a significant reduction in the antioxidant effect.

In order to solve this problem, antioxidants having carbon-carbon double bonds in their molecules so as to be crosslinkable to polymers have been developed. For example, there are known reactive antioxidants having a hindered phenol group and an acrylic group, or a hindered phenol group and a vinyl group in the same molecule, as shown by the formula: 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.

[Problem M to be solved by the invention] In recent years, the demand for using polymeric materials at higher temperatures and for longer periods of time has been increasing. As a means to meet this requirement, a method is known in which a phenolic antioxidant is used in combination with an sulfur-containing or phosphorus-containing antioxidant.

In this case, if a reactive phenolic antioxidant as described above is used in combination with a sulfur-containing or phosphorus-containing antioxidant, blooming and dissipation of the phenolic antioxidant can be prevented. However, similar to phenolic antioxidants, sulfur-containing or phosphorus-containing antioxidants
There is a problem of blooming and dissipation from polymer compositions due to long-term use at high temperatures, and improvements are desired.

The present invention aims to provide an antioxidant that has a sufficient antioxidant effect and excellent blooming resistance, and a polymer composition containing the same.

[Means for Solving Problem 9] The above problem is solved by the formula: %Formula% [In the formula, L%R7 and R3 represent an organic group, and at least one is a group having a carbon-carbon unsaturated bond. . This problem can be solved by using an antioxidant consisting of a phosphorus compound shown in .

In the above formula, at least 6 of R1, R9 and R5
One is a group having a carbon-carbon unsaturated bond, and examples include an allyloxy group, an acryloxy group, a methacryloxy group, and a vinyl group. By introducing such a group into the molecule, crosslinking with the polymer becomes possible, and the occurrence of blooming and dissipation of the antioxidant can be significantly reduced. As other organic groups, alkyl groups having 1 to 18 carbon atoms are preferred.

The antioxidant of the present invention can be prepared by converting phosphorus trichloride into an unsaturated alcohol, a mixture of an unsaturated alcohol and a saturated alcohol, or an unsaturated alcohol in the presence of a tertiary amine in a solvent such as hexane or petroleum ether. After reacting with a mixture of an alcohol and a phenol derivative and separating the hydrochloride of the tertiary amine by an appropriate method, the resulting reaction product can be obtained by concentrating it.

Examples of the unsaturated alcohol include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, allyl alcohol, trimethylolpropane dimethacrylate, pentaerythritol triacrylate, glycerin monoallyl ether, and cinnamyl alcohol.

Examples of the saturated alcohol include n-octatool, n-tenol, dodecanol, ethylene glycols, and benzyl alcohol. Also,
Examples of phenol derivatives include phenol and monononylphenol. These compounds are appropriately selected as required and used alone or as a mixture.

The reactive antioxidant thus obtained is added to a polymer (0.1 to 20% by weight, preferably 0.5 to 1% by weight, based on the
A polymer composition is obtained by blending 0% by weight into a polymer material. Preferably, it is combined with an appropriate amount of a phenolic antioxidant.

The type of polymer material is not particularly limited, and includes polyolefins such as polyethylene, ethylene copolymers, polyvinyl chloride, and polyvinyl acetate, thermoplastic elastomers such as olefins, polyesters, polyamides, polyurethanes, and polystyrenes. Examples include rubbers such as rubber, ethylene-propylene copolymer, and butyl rubber.

In addition, appropriate amounts of compounding agents that are commonly blended in these, such as processing stabilizers, lubricants, fillers, reinforcing agents, flame retardants, and foaming agents, may be blended. Furthermore, it is possible to add known sulfur-containing or phosphorus-containing antioxidants.

The above antioxidant is mixed with a polymeric material using a commonly used mixer, such as an oven roll mixer or a Banbury mixer-1 multi-shaft mixer, to obtain a polymeric composition. After shaping the resulting polymeric composition, the antioxidant is crosslinked to the polymer. In this case, the antioxidant is reacted with the polymer using known methods, such as irradiation with ionizing radiation or a chemical crosslinking agent or a combination of both. This operation
It can be carried out by methods and devices known per se and commonly used. The irradiation dose of ionizing radiation can be set in the range of 1 to 50 Mrad.

Chemical crosslinking agents may also be used in conventional amounts of known crosslinking agents commonly used for crosslinking polymers. For example, crosslinking agents such as organic perokind, polyamine, sulfur, and oximes can be used.

Alternatively, the above-mentioned antioxidant may be melt-mixed into the polymeric material and simultaneously cross-linked in the presence of an organic peroxide using a single-screw or multi-screw mixer.

[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.

Example 1 1 liter volume 3 with stirrer, addition funnel and cooling tube
N, N-1 ethylaniline (44,79) and hydroxyethyl acrylate (7,
29), a petroleum ether (100zC) solution of monononylphenol (14,79) was introduced, and a petroleum ether (50zC) solution of distilled phosphorus trichloride (t3.7g) was introduced into the dropping funnel.
Added xO solution. The reaction vessel was cooled in a cold water bath, and the petroleum ether solution of phosphorus trichloride was added dropwise to the reaction vessel while stirring. After the dropwise addition was completed, the mixture was refluxed at 50° C. for 1 hour while stirring. After cooling to room temperature, the resulting suspended N,N-diethylaniline hydrochloride was separated by filtration and then washed with petroleum ether. The washing solution and filtrate were combined and concentrated to obtain phosphorus compound 529.

Low density polyethylene (melt index 20°3) 1
00 parts by weight were blended with 3 parts by weight of the phosphorus compound previously obtained and direct weight parts of tetrakis-[methylene-3-(3',5゜di-L-butyl-4゛-hydroxyphenyl)propionate comethane. A polyethylene composition was prepared by mixing in an oven roll mixer at . 140℃, 1
Using a hot press machine under the conditions of 0 minutes, the resulting composition was heated to a thickness of I.

It was molded into a sheet of Oxz. This was crosslinked by irradiation with an electron beam of 15 Mrad at an accelerating voltage of IMeV. The gel fraction of the sheet after xylene extraction was 55%.

The obtained sheet was heated in a constant temperature bath at 180°C for 308 hours (72
0 hours) and allowed to age, and the tensile strength and elongation at break were measured. The tensile strength at break and elongation at break of the sheet before aging were measured using the formula: % Formula % () [where Xa represents the tensile strength or elongation after aging and Xo represents the tensile strength or elongation before aging]. ] The retention rate was calculated from.

As a result, the tensile strength retention rate after aging was 92% and the elongation retention rate was 76%.

Example 2 Ethylene-ethyl acrylate copolymer (EEA1 melt index 20, 7, ethyl acrylate content = 19
%) to 100 parts by weight, 4 parts ft of phosphorus compound prepared according to the procedure shown in Example 1, n-octadecyl-3°
, 1 part by weight of 5'-di-t-butylphenylpropionate were mixed in an oven roll mixer at 100°C to prepare an EEA composition. Using a heat press machine at 120°C for 10 minutes, the resulting composition was pressed to a thickness of 1Oxx.
It was formed into a sheet. 2O electron beam with accelerating voltage IMeV
This was crosslinked by Mrad irradiation. The gel fraction of the sheet after xylene extraction was 62%.

As a result of carrying out an aging test according to the procedure shown in Example 1, the retention rate of tensile strength after aging was 92% and the retention rate of elongation was 8.
It was 1%.

Example 3 According to the procedure shown in Example 1, a mixture of hydroxyethyl acrylate and monododecyl alcohol in a molar ratio of 1:2 was reacted with phosphorus trichloride to obtain a phosphorus compound (yield: 81%).

To 100 parts by weight of ethylene-vinyl acetate copolymer (EVA, melt index = 2.0, vinyl acetate content TL: 11%), 2 parts by weight of the above phosphorus compound, n-octadecyl-3'',5''-di-t -0.5 parts by weight of butylphenylpropionate was blended and mixed in an oven roll mixer at 120°C to prepare an EVA composition.
The obtained composition was molded into a sheet having a thickness of J and Oxz using a hot press machine under conditions of 10 minutes. Acceleration voltage IMeV
This was crosslinked by irradiation with an electron beam of 20 Mrad. The gel fraction of the sheet in xylene extraction was 50%.

As a result of carrying out an aging test according to the procedure shown in Example 1, the retention rate of tensile strength after aging was 88%, and the retention rate of elongation was 6.
It was 8%.

Comparative example 1 Low density polyethylene (melt index = 0°3) 1
00 parts by weight, tetrakis-[methylene-3=(3°,
111,571 parts by weight of 5°-di-t-butyl-4°-hydroxyphenyl)propione was blended and mixed in an oven roll mixer at 120°C to prepare a polyethylene composition. The obtained composition was molded into a sheet having a thickness of 1.01111 mm using a hot press machine at 140° C. for 10 minutes. This was crosslinked by irradiating 15 Mrad of electron beam with an accelerating voltage of 1 MeV. The gel fraction of the sheet after xylene extraction was 59%.

As a result of carrying out an aging test according to the procedure shown in Example 1, the retention rate of tensile strength after aging was 2% and the retention rate of elongation was 1%.
Met.

Comparative Example 2 Ethylene-ethyl acrylate copolymer (EEA1 melt index: 0.7, ethyl acrylate content +19
%) 100 parts by weight of stirring, 4 parts by weight of diphenyldecyl phosphite as a phosphorus compound, tetrakis[methylene-3-
(3°,5"-di-t-butyl-4"-hydroxyphenyl)propione-111571 parts by weight was blended, and 10
The EEA composite was prepared by mixing in an oven roll mixer at 0°C.

The obtained composition was molded into a sheet having a thickness of 1.0 .mu.m using a hot press machine at 120.degree. C. for 10 minutes. This was crosslinked by irradiation with an electron beam of 20 Mrad at an accelerating voltage of IMeV. The gel fraction of the sheet after xylene extraction was 48%.

As a result of carrying out an aging test according to the procedure shown in Example 1, the retention rate of tensile strength after aging was 63%, and the retention rate of elongation was 1.
It was 6%.

Salt Mosquito 1 Ethylene-ethyl acrylate copolymer (EEA, melt index 20.7, ethyl acrylate content: 19
%), 2 parts by weight of dilauryl thiodipropionate and 1 part by weight of n-octadecyl-3°,5°-di-t-butylphenylpropionate were added to 100 parts by weight.
The EEA composition was prepared by mixing in an open roll mixer at . Using a heat press machine at 120°C for 10 minutes, the resulting composition was pressed to a thickness of 1. It was molded into a sheet of Oxx.

This was crosslinked by irradiation with an electron beam of 20 Mrad at an accelerating voltage of IMeV. The gel fraction of the sheet after xylene extraction is 4
It was 3%.

As a result of carrying out an aging test according to the procedure shown in Example 1, the retention rate of tensile strength after aging was 27%, and the retention rate of elongation was 5.
%Met.

Comparative example 4 Low density polyethylene (melt index = 0°3) 1
00 parts by weight, 1 part by weight of acrylic ester of 3.5-di-t-butyl-4 hydroxyalcohol was blended,
A polyethylene composition was prepared by mixing in an oven roll mixer at 20°C.

Using a heat press machine at 140°C for 10 minutes, the resulting composition was pressed to a thickness of 1. It was molded into a sheet of Oxx. This was crosslinked by irradiation with an electron beam of 15 Mrad at an accelerating voltage of IMeV. The gel fraction of the sheet after xylene extraction was 47%.

As a result of carrying out an aging test according to the procedure shown in Example 1, the retention rate of tensile strength after aging was 2% and the retention rate of elongation was 1%.
Met.

[Effects of the Invention] As explained above, according to the present invention, it is possible to obtain an antioxidant whose antioxidant effect is less reduced due to blooming and dissipation under high temperature and long-term conditions, and which is less likely to reduce the antioxidant effect than other antioxidants. A polymer composition having a high degree of heat resistance can be obtained by using an agent, especially a phenolic antioxidant, preferably a reactive phenolic antioxidant.

Claims (1)

[Claims] 1. Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R_1, R_2 and R_3 represent an organic group,
At least one is a group having a carbon-carbon unsaturated bond. ] An antioxidant consisting of a phosphorus compound represented by: 2. A polymer composition comprising 0.1 to 20% by weight of the phosphorus compound according to claim 1 and crosslinked with a polymer.