DE1694258C - Polyphenylene oxides stabilized against the effects of light and heat - Google Patents

Description

Pie invention relates to polyphenylene oxides, which by organic phosphites, hydrazines, uenzoic anhydride and their mixtures are stabilized against the effects of light and heat.

From the Belgian patent specification 635 350, polyphenylene oxides are known as a new KunstsiolTamil. They are characterized by the combination of excellent mechanical, chemical and electrical Properties in a wide temperature range. The polyphenylene oxides also show good stability against common aggressive organic solvents. Due to these properties are suitable the polyphenylene oxides for a large number of technical applications

In contrast, the polyphenylene oxides have only moderate resistance to light and heat. When They are exposed to direct sunlight or high levels of eniperaluric acid for a long period of time chemical reactions take place which result in discoloration and embrittlement of the polymer. The ^ o The use of these plastics is therefore limited to the extent that they are unsuitable for purposes where high temperatures occur or outdoor use is required.

The subject of the invention are against action;> MMi light and tub stabilized polyphenylene oxides. which are characterized in that they are in dispersion D. 1 to ρ percent by weight organic Phosphites or hiophosphites. Hydrazines and or Ben / oes.mreanhydnd contained as stabilizers «3

These compounds are known as stabilizers for various polymers. For example, phenylphosphite is added to accelerate curing and increase chemical resistance, but it is only effective in amounts of over 11% by weight. It is also effective known to add l'noriunophophite to the polyethers formed by 2.2-bisi4-hydro \ ypheny! " lenoxyden little Ver-K 'xv.'! Ungen. v <ohingegen certain stabilizers and sei'M'hiedene combinations wn stabilizers in (V ν phenyl lenoxyden äuLkrrst effective> ind. \ llgciito 11 IALU -.ich not predict we Chemical bonds / for the stabilization of a new PoN-pvien andeier Süuklur -.jnil. The citindupgst: ema (i used stabilizers thus Kui '-> lsU! | Te on Ba>i> from Polv phenylciioxvden ^ u are redeemable besides Jen mechanical, eheivschen and elek'.nschcp I 1 Jen schatten .tuch cmc £ ute borrowed 'and Wjrmeix ^.'. indigkeit / Eigen

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1 l.il

I nlaury; phosphite.
\ eetvlphenylhydraz.in.
1 nlaurvl phosphite.
Aeetylpheny! Hydrazine,
anhydrous hydrazine.
I rilaurvlphosphite.
tk'ri / wsa'ir anhydride.
anhydrous HviJra / »;:.
l'nlitijrylphospltit.

fto

7. I.

Part 1

2 parts

Part 1

2 parts

3 parts
2 parts
or

part
2 parts

Acetylphenylhydrazine,

anhydrous hydrazine,

Ν, Ν'-diacetylhydrazine,

Trilauryl phosphite,

Benzoic anhydride,

Trilauryl phosphite

Trilauryl phosphite,
Benzoic anhydride.

The poly phenylene oxides falling within the scope of the invention have the following general form

R stands for hydrogen, a monovalent hydrocarbon or hydrocarbon oxy radical free of tertiary "C" atoms, a monovalent halogenated hydrocarbon or halohydrocarbonoxy radical free of tertiary "C atoms and with at least 2 carbon atoms between the halogen atom and the phenol nucleus, R ' has the same meaning as R ode is a halogen, and η is a number greater than KK)

Typical examples of the monovalent hydrocarbon radicals that protrude through R and R 'in the represented by the formula are alkyl radicals. wu Methyl. Ethyl. 'Propyl. Cyclobutyl. Hcxyl. Cycln hexyl and octadecyl. Alkenyl radicals such as vinyl. Allyl Cyclobutynyl and linolyl. Alkynyl radicals. like Propar gyl, aryl radicals. like phenyl. Tolvl. Ethylphenyl unc Naphthyl. Aralky residues. like benzyl and phenyl ether The monovalent halogenated hydrocarbons can can be the same residues as the previous one th hydrocarbon radicals with the exception of meth and i-halo res; en. being one or more water stot atoms are replaced by halogen and halogen hydrocarbon radicals with at least 2 C'-Alnmcr / Wiper the halogen and the free valence gcbil be det. Examples are 2-chloroeth> l 2-bromoethyl. 2-Fluoriithyl and 2.2-Dichloräthvl.

! "ypischc Examples of monovalent () xy charcoals ··>. .isser Substance residues are methoxy. Atnoxy. Propoxy. i ^ opropoxy. Butoxy. Vinoxy urJ Phenyloty. The one'-er tigirn Halogenoxykohlen'.vas.-ierstoffReste you can same red scm as the above Cabbage residues with the exception of M.'h ox '. and> i-H..iloiienalkoi> resten, '.vnbei ein' ~> de; Replace several hydrogen atoms with a halogen ^ md and Haloüervx'.Kohlwasserstiiffreste mr '* enii: > at least 2 carbon atoms / between the halogen and the free valence. Typical examples are: 2-chloroethoxy. 2-bromoethoxy. 2-fluoro athoxv and 2,2-dichloroethoxy

The term "polyphenylene oxide" used here the substituted and the unsubstitmor fall th polymers

When testing the stabilizers for PoN-phenyleno.xyde Compounds to be used have been found to be organic phosphites. Hydrazines and bi'TMuesuureunhydnd the polyphenylene oxides sow-oh in relation to color al.s juc'h physical properties stabilize. In addition, special Eraebnis; < if received combinations

these materials are used. In a preferred embodiment of the invention are thus an organic phosphite, benzoic anhydride and a hydrazine as stabilizers for polyphenylene oxides second hand.

The amount of stabilizer used is generally in the range between 0.1 and 6 percent by weight. Higher concentrations dilute the polymer and maintain its physical properties to affect. When organic phosphites are used alone, an amount will suffice up to 2 percent by weight. It is not necessary that the amount of organic phosphite be 2 percent by weight to be exceeded, since no further improvements can be found with higher amounts.

When benzoic anhydride is used alone. ♦ Ground improved results with amounts up to 5 percent by weight achieved. In the case of hydrazines, amounts of up to 2 percent by weight are sufficient.

When using the various combinations of stabilizers, the total amount of stabilizers should be between 0.1 and 6 percent by weight; a typical stabilizer mixture consists, for example, of 1% of a phosphite. 1 to 2 percent by weight of icnzoic anhydride and 1 to 3 percent by weight of a hydrazine.

Typical examples of phosphines that can be used as stabilizers for polyphenylene oxides are Phcnyldoda-ylphtv.phit. Trichloroethyl phosphite. Tridecyl phosphite. Dilauryl phosphite. Tril.iuryl phosphite. Trilauryltrithiophosphite and triocta- «lycylphosphite. Typical examples of suitable hydrazines are diacctyl hydrazine. Discoyl hydrazine. Acelylphenylhydrazine. Phenylhydrazine. Diphenylhydra- / ίιι. NN-benzylphenylhydrazine. 1-methyl-1-phenyl- ^ hydrazine. NN-dilaurylhyrazine. 1.1-Dimet hy! Hydrazine and hydrazine (anhydrous).

The aforementioned organic phosphites and hydrazines are typical examples of compounds make the polyphenylene oxides more resistant to light and heat, but it has been found that particularly good results are obtained when Trikiurylpho> phit. Trioctadccyl phosphite. Diacctvlhytlra / in. Acetylphenylhydrazine and fI> dra / .in (anhydrous) be used. In addition, excellent results are obtained with 4s uenzocsuricin hydride. Accordingly, the use of the aforementioned stabilizers either alone or in ! Combination represents a preferred embodiment of the invention.

Line setting on a theory is not intended however, it is believed that it is necessary to stabilize polyphenylene oxide. ".let fin antioxidant, a means to stabilize the terminal groups and an additional material that works with undesired impurities reacts in the polymer and neutralizes them, must be present. The following formula represents the last two units of a polymer chain of a polyphenylene oxide and corresponds to the above formula I '*

-o ~

(II)

Ί R.

In the above formula, R and R 'have the same meaning as in formula I. With regard to the Formula II is believed to cause oxidation at higher temperatures over a longer period of time at any radicals R or R 'or a degradation due to the tendency of the ether bonds to form of peroxide can take place. It is therefore believed that an antioxidant must be added to prevent this form of oxidation. However, it has been found that only certain antioxidants are effective.

The phenolic antioxidants, for example are ineffective.

In addition, the hydroxyl group at the end of the polymer chain is reactive. It is therefore advisable to to add a compound that is able to react with the hydroxyl group in order not to prevent it to make responsive.

In putting the above theory into practice, it was found that a number of the known antioxidants were unsuitable. For example, the phenolic antioxidants, wx are 2-naphthol. 2 - Aceto - 1 - naphthol and diacelylp-aminophenol. no effective stabilizers for polyphenylene oxides. They also cause some discoloration of the polymer. Ester-based antioxidants such as dilauryl thiodipropionate and / i-naphthy ibenzoate have also been found. as ineffective. Under these circumstances it was very surprising that the organic phosphites are effective stabilizers for polyphenylene oxides.

As already mentioned, benzoic anhydride is a stabilizer for the polyphenylene oxides. It will believed that it prevents undesirable reactions of the phenolic hydroxyl group and these thereby protects.

It is believed that the hydrazines that also stabilize polyphenylene oxides, act as antioxidants and with undesirable impurities react contained in the polymer.

It is immaterial how the stabilizer affects the polymers is added. Any known methods for incorporating additives into polymers can Can be applied when, for example, the desired stabilizer is soluble in a solvent is. in which the polymer is also soluble. can «Jas polymers and the stabilizer in the solvent are dissolved, whereupon the solvent is evaporated. If the stabilizer is not in a solvent is soluble. it can be in powder form to powder form Polymers can be added by mixing the two ingredients according to known methods. It is also possible to add the stabilizer during the polymerization of the monomer. Here becomes a soluble stabilizer; the dissolved monomer added, followed by polymerization.

The use of stabilizers improves both color fastness and thermal stability the polyphenylene oxide improves. For example, with additions of 0.1 to 1% of an organic Phosphite after 5 to 5 days of exposure to high levels Temperatures improves the thermal stability by 50 to I (X)%, depending on the phosphite used. In addition, there was only a very slight darkening of the polymer after an exposure time of high temperatures up to 7 days. By adding 0.5 to 1% hydrazine / U polyphe-

nylene oxide, the thermal stability is improved by 100 to 150%. Here, too, there was only a slight darkening observed after exposure for 6 to 7 days. Combinations with phosphites and hydrazine give better color stability, and the heat resistance is improved by 200 to 300%. With various special combinations it is possible to increase the color stability and thermal Improve stability even further.

IO

example 1

This example illustrates the effect of adding an organic phosphite to a polyphenylene oxide. Numerous organic phosphites were added in varying amounts. In all The desired amount of the organic phosphite was dissolved in 1 l of heptane. To this solution 250 g of poly (2.6-dimethyl-1.4-phenylene) oxide with an intrinsic viscosity of 0.60 were obtained. mixed,:; en in chloroform added at 30 C. and dissolved in the solvent. The solution was then poured into a bowl and Left to stand overnight while the solvent evaporated. The dry polymer obtained was pulverized and at temperatures depending on the viT.vcrdcler. Addition and the concentration used between 271 and 316 C, extruded. The strand was granulated by chopping. Granulate samples of 2 g each were then placed between metal plates at a temperature which depends on the one used Additive and its concentration was between 249 and 288 C. to slides an average Pressed thickness of 0.38 mm. The press foils were then exposed to elevated temperatures for a long time, by keeping the foil strips in a convection oven which was kept at 150 ° C. The flexibility The foils were determined at intervals of 24 hours until the samples were brittle. The exam the flexibility was achieved by bending the film strip by 360. until it was broken. the Color stabilization was determined by visual comparison between the films containing the additive and a additive-free standard film determined. The crhal'encn Results are given in Table I below.

45

Table I.

The flow of organic substances as a stabilizer for poly-12.6-dimethyl-1.4-phen \ len) oxide

Flexibility (average number of kinks to break) ')

/.usiil/. (weight pro / cnt

(I.Hler (IlT

temperature
by IMI C

Without addition.

! Days

2.5

0.1 trilauryl phosphate. .

Ί t) iirth «hnin for 5 hi :, for samples

Days [repay

0.5 0

0.5

ί I

Color change

strong
Darken
easy
Darken

Addition, percent by weight

Duration of action of the

temperature
from 150 C

4th
Days

0.5 trilauryl phosphite ...

1.0
2.0
3.0
0.5

0.1 1.0

0.25
3.0

0.5
0.5

Trilauryl phosphite ...
Trilauryl phosphite ...
Trilauryl phosphite ...
Trioctadecyl

phosphite

Triethydiphosphite

Phenyl neopentyl phosphite

commercially available

Alkaryl phosphite

commercially available

Alkaryl phosphite

Tridecyl phosphite ....
Phenyldidecyl phosphite

Taee

3.5 0
3.5 2

~> Ι π

Days

3.5
3

_i 0 i 0

Color change

2 j 0

0 y 3.5! 0

easy
Darken

the same
the same
the same

the same
the same

the same
the same

the same
desul.

3.5 '0 the same.

From the table above it can be seen that phosphites in a concentration of up to about 2% greatly improve the flexibility of the polyphenylene oxides and at the same time prevent the polymer from darkening. With 0.1 percent by weight trilauryl phosphite tore an average of 5 to 6 specimens after three kinks, after having reached 5 days of a temperature were exposed to 150 C. Similar samples withstood without the addition of trilauryl phosphite only an average of half a kink. With the addition of 3 percent by weight of the alkylicrlcn aryl phosphite the polyphenylene oxide sample became more brittle than the sample without addition. It is believed that the reason for this is the dilution of the polymer due to the high proportion of the added alkaryl phosphite located.

Compare

So well-known phenolic antioxidants were with the same poly- (2.6-dimethy'-l.4-phenylene) -ox> il mixed in exactly the same way as in Example I. The following phenolic antioxidants were used: 2-naphthol. 2-aceto-l-ir.iphlhol.

Diacctyl-p aminophenol. t-butylcatechol. 2.2'-methylene -! "> Is- (4-methyll) -6-t-butylpnenol and (2.2-thiobis - (4-1 - octylphenalal)) - η - butylamine - η ickcl (II). In in all cases the antioxidant was used in an amount of 2% or less. The examined Antioxidants were in no way effective. The difference between the nylon oxides. the the phenolic antioxidants, and the additive-free polyphenylene oxide was not essential. The inability of phenolic antioxidants. to improve the stability of polyphenylene oxide, was surprising as it was expected that both the organic phosphites and the phenolic Antioxidants the bleaching behavior Iw hm

as they would with other plastics. z. B. Polyvinyl chloride, have the same effect. This example illustrates the unpredictable Nalur of stabilizers and the difficulty of choosing a suitable stabilizer for a particular plastic to find.

Example 2

In this case the same polyphenylene oxide and the same procedure as in Example I was used, however, various anhydrides have been used in place of the organic phosphites. The following Results were obtained:

Table 2

Influence of an anhydride as a stabilizer
Door poly (2,6-dimethyI-l.4-phenylene) oxide

flexibility

(average number of kinks
until break)

Addition, percent by weight

Without addition

1 Benzoic anhydride ..

Duration of action of the

temperature
from 150 C

Days [ days

2.5 0.5

3.5

3 Benzoic anhydride .. 7
5 benzoic anhydride .. | l5

Comparative experiments

1 phthalic anhydride .. \ 0 j -

5 phthalic anhydride ...; 2 0

Acetic anhydride, 2 , 0

Lauric anhydride .... | 2 1

Days

Colorandine

strong
Darken

easy
Darken the same.
the same

strong
Darken the same.
the same
desel.

From the table above it can be seen that the anhydrides as a class are not effective stabilizers are for polyphenylene oxides. The only exception to this is benzoic anhydride. Using this anhydride in amounts up to 5 ° o was a significant improvement in flexibility and the color stability achieved. The reason why Benzoic anhydride is effective as a stabilizer. while other anhydrides are ineffective, is not clarified, but this further illustrates the fact that the influence of stabilizers on various Plastics is unpredictable.

H c i s ρ i e I 3

The same polyphenylene oxide and the same

The procedure as in Example 1 was used.

however, various hulra / inc were used in place of the organic phosphites. The following Results were obtained:

Table 3

Influence of hydrazines as a stabilizer for poly (2,6-dimethyl-1,4-phenylene) oxide

flexibility

(average number of bends' ■ ^s to break)

J action da d

Additive. Weight percent

Without addition

0.5 N, N'-diacetyl hydrazine

Discoyl hydrazine

Acetylphynylhydrazine ....
Hydrazine (anhydrous) ....

above the temperature of l> 0 (

Days days

2.51 0.5

I 0

rarr> change

strong darkening

Slight darkening like the like the like

The table above clearly shows that the hydrazines have some effect on both the color stability and the thermal Have stability of polyphenylene oxides. The influence of the hydrazines, however, is more pronounced when they are used in Combination with other stabilizers can be used as illustrated in the following example.

Example 4

Two component mixtures of organic phosphites, hydrazines and benzoic anhydride (all connections that you ·: »as suitable stabilizers for polyphenylene oxides proved) were with that mentioned in Example 1 Polyphenylene oxide mixed in the manner described there. The results obtained are as follows mentioned in table 4.

Table 4

Influence of various combinations of stabilizers on poly (Z6-dimethyl-1,4-phenylene oxide

flexibility

(average number of kinks to break 1

Duration of exposure to tempera; ur addition. Weight percent j of 150 C:

I 4! 5 6 - jdaysjdays days days

Without addition i Z5! 0.5 ^; 0. -

Color change

strong Darken

(0

f-'ort set / iinc

Duration of action. the temperature K _lr h-

To <; it /. GewichKpro / ent | 'On I 50 C _,'

i 4 5 y Λ y 7! days daysjdays days

1.0 Trilaurvlphosphite 5.5 j 4 0 Φ.5 Acetylphem I- |

hydrazine i

1.0 Ben / oesäure-

anhydride ί.Ο trilauryl phosphite

Φ.5 N.N-diacetyl-

hydrazine 1.0 trilauryl phosphite

) .O Benzoic anhydride ί.Ο trilauryl phosphite

1.0 benzoic anhydride Φ.Ι trilauryl phosphite

3.5 ι 2

4.5 ! 2 j 0

3.5

I! O

slight darkening of the same.

like. like. like.

'5

.1 °

From the table above it can be seen that "Great Improvements in Thermal Stability of Pr-Iyphenylene Oxides with Various Combinations of Organic Phosphite. Hydrazine and benzoic anhydride can be achieved.

Example 5

Various combinations of an organic phosphite with benzoic anhydride have been used with a Polyphenylene oxide mixed in the manner described in Example I. A polyphenylene oxide was used Poly (Z6-dinothyl-1,4-phenylene) oxide with a limiting viscosity of 0.52 dl g (measured in chloroform at OK C) used. The following results were obtained:

Table 5 Influence of different combinations

of stabilizers on poly (Z6-dimethyl-1,4-phenylene) oxide

flexibility

(average number of kinks to break)

45

Zuvjt /. G.'Aichispro / ent Fin Wirkunes-
Duration of
temperature
ion I5O C Color
modification (1 i ⁷
Days to go Without addition I 0 strong
To
darken 5.5 3.5 easy
To
darken 0.5 trilauni phosphite
1.0 benzoic anhydride 3 i 1.5 the same 0.5 tetranediphenyl
phosphite) penta
erythritol
1.0 Benzoic anhydride 4 3 the same 0.5 phenyldidecyl phosphite
0.0 benzoic anhydride

From the above values it can be seen that by adding a mixture of a phosphite mil Acid anhydride to polyphenylene oxide thereof thermal stability is greatly improved.

Example 6

Three- and four-component mixtures of an organic phosphite. a hydrazine and benzoic anhydride were combined with a poly- (2,6-dimethyl- 1,4-phenylene oxide with an intrinsic viscosity of 0.53 dl g. measured in chloroform at 30.degree. C., mixed in the manner described in example I. The stabilized samples were reheated to 150 ° C. The following results were obtained:

Influence of different combinations

of stabilizers on poly (2,6-dimethyl-1,4-phenylene) oxide

flexibility

! average number of kinks until the break!

. Weight percent

financial effect of the

temperature from 150 C

Without addition

-τ

1.0 trilauryl phosphite 1.0 acetylphenyl hydrazine 2.0 hydrazine (anhydrous! 1.0 trilauryl phosphite ZO benzoic anhydride 2.0 hydrazine (anhydrous) 1.0 trilauryl phosphite 1.0 benzoic anhydride 1.0 acetylphenylhydrazine 2.0 hydrazine (anhydrous)

6th
Days _ ^Ta i ^c _ 7th 5.5 6th 4th 7th 5.5

l-arr> modification

strong Darken

easy Darken the same.

the same

From the above values it can be seen that an even greater thermal stability is achieved with certain three- and four-component mixtures of Stabiliv
goals is achievable.

Claims (1)

Claim: Polyphenylene oxides of the formula stabilized against the effects of light and heat - O- in which R stands for hydrogen, a monovalent hydrocarbon free of tertiary <T-C atoms or hydrocarbon oxy radical. one of tertiary Monovalent halohydrocarbon or halohydrocarbonoxy radicals containing no π-carbon atoms with no two carbon atoms between the halogen atom and the phenolic nucleus. R 'has the same meaning as R or halogen and η is an s Number greater than MH). marked by a total content of 0.1 to 5 percent by weight of organic phosphites or thiophosphiles. Hydrains and or benzocic acid hydride as stabilizers.