DE3000744B2 - Heat-stabilized molding compounds based on graft polymers - Google Patents

Description

(a) 1 to 12 carbon atoms in each alkyl group;

(b) at least about 85% of one of the o-positions in the benzene nuclei is substituted by alkyl radicals with 3 to 12 carbon atoms and

(c) at least about 85% of the p-positions in each benzene nucleus is unsubstituted or substituted by methyl groups

2. Molding compositions according to claim 1, characterized by a content of a mixture of tris (alkylphenyl) phosphites of the general formula

in which at least about 85% of the radicals R ^{2 are} alkyl radicals with 3 to 12 carbon atoms or cycloalkyl radicals and the remainder represents hydrogen atoms and at least about 85% of the radicals R> represent methyl groups or hydrogen atoms.

3. Molding compositions according to claim 1, characterized by a content of a tris (alkylphenyl) phosphite of the general formula

in which R is an alkyl radical having 8 to ^ carbon atoms.

Graft polymers made from graftable, rubber-like stock polymers based on dienes and side branches made from copolymers based on aromatic monovinylidene compounds and Olefinically unsaturated nitriles or esters are usually processed at high temperatures. This accelerates the degradation of the polymers. The mixture is used to produce molding compositions which contain various stabilizers processed on a heated two-roll mill or in a heated internal mixer, for example a Banbury mixer. The temperatures at which these mixing operations are performed

relatively high, in any case well above the temperature at which the polymers become fluid. At these temperatures the polymers tend to discolour and become brittle. Such a one The end products cannot accept a deterioration in quality.

There are a number of thermal stabilizers for thermoplastic polymers, including organic phosphites. These connections are effective though Heat stabilizers, but their usefulness is limited due to their susceptibility to hydrolysis The hydrolysis is accompanied by a corresponding loss of heat stabilization in the polymer When using solid phosphites, hydrolysis is often accompanied by a tendency to cake, i.e. the usually granular organic Phosphite glued together to form a single solid i ^ kjck.

Numerous attempts have been made to solve this problem. Additives such as triisopropanolamine, give organic phosphites an increased hydrolysis stability. The solid phosphites can under Exclusion of moisture, for example in polyethylene bags, can be stored until use. All of these measures, while helpful, have not eliminated the problem, nor did they eliminate one Solution to this problem given.

In GB-PS 14 90 938 are symmetrical triaryl phosphites of the general formula

_ J

described in the Ri a tert-butyl, 1,1-dimethyl propyl, cyclohexyl or phenyl group and one of the radicals R2 and R _{3 is} a hydrogen atom and the other is a hydrogen atom, a methyl, tert-butyl, 1,1-dimethylpropyl, cyclohexyl or phenyl group. This PS also includes the use of this Compounds described together with phenolic antioxidants in olefin polymers.

In US-PS 27 33 226 aryl phosphites are described, which by alkyl radicals with at least 8 carbon atoms are substituted. Further is hers Use as stabilizers for synthetic rubber described. The alkyl radicals can be in the o, p or m position to the oxygen atom.

From US-PS 35 78 620 is the stabilization of non-rubber-like unsaturated copolymers cyclic polyenes by means of a mixture of one

Epoxide and a tri- (alkylphenyl) phosphite with 8 to

30 carbon atoms in the alkyl radical known. Special Tri- (o-octylphenyl) phosphite is mentioned.

From US-PS 30 80 338 is the use

any conventional phosphite in combination with a phenolic antioxidant for Stabilization of synthetic rubber-like polymers known. Tri- (ooctylphenyl) phosphite is also specifically mentioned here.

Finally, from US Pat. No. 2,752,319, the stabilization of polyvinyl chloride by means of a combination from a Glykoles'.er an organic acid, a triaryl phosphite (to stabilize the ester) and

a metal compound known. The aryl phosphite can be tri- (o-cyc | ohexyjphenyl> -phosphnite.

The invention is based on the object of providing heat-stabilized molding compositions based on Graft polymers made from graftable, rubber-like stock polymers based on dienes and side branches made from copolymers based on aromatic monovinylidene compounds and To create olefinically unsaturated nitriles or esters, which can also be used in a humid atmosphere the heat stabilizing effect is retained as far as possible. This object is achieved by the invention The invention thus relates to the subject matter characterized in claims 1 to 3.

The preparation of the tris (alkylphenyl) phosphites used according to the invention initially requires the Production of the alkylphenol and then the reaction of the alkylphenol with phosphorus trichloride. In the first stage an acylphenol is reduced or hydrogenated to the corresponding alkylphmol. This can expediently done by means of zinc and hydrochloric acid. A An alternative method that gives slightly better results is the alkylation of phenol or p-cresol with the corresponding olefin in the presence of a catalyst. Is preferably used as a catalyst Aluminum powder or in particular the aluminum phenolate used in the implementation of Aluminum is formed with the phenol used. In this alkylation, the o-isomer is produced in high yield obtained while the p-position is little or no is substituted.

The reaction of the o-alkylphenol with phosphorus trichloride proceeds in a good yield with a relatively high yield high temperatures. The product can be distilled. A clear, colorless liquid is obtained. Furthermore, the reaction product can be stripped off under reduced pressure, and the remaining liquid is used as a product

This product, i.e. the tris (o-alkylphenyl) phosphite, is extremely stable against Excellent hydrolysis. Accordingly, molding compositions based on graft copolymers show of the type characterized above a long-term heat stabilization. Particularly favorable results are obtained when the molding compounds according to the invention still contain a phenolic antioxidant.

According to the invention, the graft polymers used are acrylonitrile-butadiene-styrene polymers (ABS polymers), methyl methylate-butadiene-styrene-polyw merizates (MBS polyesters) and methyl methacrylate-acrylonitrile-butadiene-styrene polymers (MABS polyesters) are preferred

These polymers are graftable, rubber-like stock polymers based on dienes with side branches made from copolymers based on aromatic monovinylidene compounds and olefinically unsaturated nitriles or esters. The rubber-like base polymer is a diene rubber with a second-order transition temperature of at most ⁰ ° C and preferably at most -20 ° C, determined in accordance with ASTM test standard D-746-52 T. It is a polymer of at least one conjugated 1, 3-diene, such as butadiene, isoprene, piperylene or chloroprene. Examples of rubber-like parent polymers of this type are homopolymers and copolymers of conjugated 1,3-dienes with up to the same weight at least one monoolefinically unsaturated monomer copolymerizable therewith, for example one aromatic monovinylidene compound, such as styrene, an alkylstyrene, such as o-, m- and p-methylstyrene, 2,4-dimethylstyrene, an arylethylstyrene or p-tert-methylstyrene, an «-alkylstyrene, such as« -methylstyrene, a-ethylstyrene or «-Methyl-p-methylstyrene, a Vinylnaphthalene, an aromatic monovinylidene compound halogenated in the aromatic radical, such as o-, m- or p-chlorostyrene, 2,4-dibromostyrene or 2-methyl-4-chlorostyrene, acrylonitrile, methacrylonitrile, an alkyl acrylate such as methyl acrylate, butyl acrylate or 2-ethylhexyl acrylate to the corresponding alkyl methacrylate, acrylamides, such as acrylamide, methacrylamide or N-butyl acrylamide, an unsaturated one Ketone, such as vinyl methyl ketone or methyl isopropenyl ketone, an «-olefin, such as ethylene or propylene, a pyridine, a vinyl ester such as vinyl acetate or vinyl stearate a vinyl or vinylidene halide such as Vinyl or vinylidene chloride or bromide.

The rubber-like Stammpolynierisat can be up to contain about 2 percent by weight of a crosslinking agent. The networking can occur when the rubber-like base polymer in the monomers for the graft copolymers, especially in the polymerization in bulk or suspension, lead to difficulties. It can also be too strong Crosslinking lead to the loss of the rubber-like properties of the parent polymer. The usual compounds are used as crosslinking agents for crosslinking rubber-like diene polymers, such as divinyl benzoL, diallyl maleate, diallyl fumarate, diallyl adipate, allyl acrylate, allyl methacrylate and also diacrylates and dimethacrylates of polyhydric alcohols, such as ethylene glycol dimethacrylate

Preferred rubber-like stock polymers consist of 75 to 100 percent by weight butadiene and / or isoprene units and up to 25 percent by weight units of aromatic monovinylidene compounds such as styrene and unsaturated nitriles, such as acrylonitrile, or their mixtures. Particularly preferred master polymers are butadiene homopolymers and copolymers with 90 to 95 percent by weight butadiene and 5 to 10 percent by weight Acrylonitrile or styrene.

The side branches of the graft copolymer used according to the invention consist essentially of aromatic monovinylidene compounds and unsaturated nitriles and / or esters as basic building blocks. These monomers are present in the side branch polymer in an amount of at least 75 and preferably at least 90 percent by weight.

Examples of the aromatic monovinylidene compounds which can be used to prepare the side branch copolymers are monoaromatic styrene (x-Alkyl monovinylidene compounds, such as -methylstyrene, -ethylstyrene and -methylvinyltoluene, -methyldialkylstyroje, ring-substituted alkylstyrenes, such as Vinyltoluene, o-ethylstyrene, p-ethylstyrene and 2,4-dimethylstyrene, styrenes halogenated in the benzene nucleus, such as o-chlorostyrene, p-chlorostyrene, o-brofnstyrene and 2,4-dichlorostyrene, styrenes substituted in the benzene ring by alkyl radicals and halogen atoms, such as 2-chloro-4-methylstyrene and 2,6-dichloro-4-methylstyrene, vinylnaphthalene and vinyl anthracene. The alkyl radicals generally contain 1 to 4 carbon atoms. Specific examples are the isopropyl and isobutyl groups. If necessary, mixtures of these aromatic mono-

vinylidene compounds are used,

Examples of the olefinically unsaturated nitriles are acrylonitrile, methacrylonitrile, ethacrylonitrile and their Mixtures,

Examples of the olefinically unsaturated esters that can be used are methyl acrylate, methyl methacrylate, n-butyl acrylate, isobutyl methacrylate and their mixtures,

Examples of the monomers that can be copolymerized with the aromatic monovinylidene compounds, unsaturated nitriles and / or esters, are conjugated 1,3-dienes, such as butadiene or isoprene, α- or ^ -unsaturated monobasic acid and their Derivatives such as acrylic acid, methacrylic acid, acrylic acid amide and methacrylic acid amide, vinyl halides such as . Vinyl chloride or vinyl bromide, vinylidene chloride or Vinylidene bromide, vinyl esters, such as vinyl acetate or vinyl propionate, dialkyl maleates or fumarates, such as Dimethyl maleate, diethyl maleate, dibutyl maleate or the corresponding fumarates. The amount of these comonomers. which may be present in these side branch copolymers depends on various factors.

The graft copolymers used according to the invention are prepared by customary processes, which are not the subject of the invention.

The alkyl radicals in those used according to the invention Tris (alkylphenyl) phosphites contain 1 to 12 carbon atoms, particularly preferred alkyl radicals are the octyl, nonyl, decyl, undecyl and dodecyl groups. These groups can be connected to the ßenzolring a primary, secondary or tertiary carbon atom can be bonded. The cycloalkyl radicals are Cyclopentyl and cyclohexyl groups in question.

The tris (alkylphenyl) phosphites according to claim 2 are derived from an alkylphenol of the general type formula

in which R "denotes a methyl group or a hydrogen atom and R ² denotes an alkyl radical having 3 to 12 carbon atoms

According to the invention, the tris (o-alkylphenyl) phosphites or tris (o-cycloalkylphenyl) phosphites are in in an amount from about 0.05 to about 5.0 parts per hundred Parts of the graft copolymer used

The usual compounds used for this purpose are used as phenolic antioxidants in collar. Specific examples are

2,6-di-tert-butyl-4-methylphenol,

2,6-di-tert-butyl-4-methoxymethylpheno ^l and

2,6-di-tert-butyl-4-methoxyphenol,

2,2'-methylenebis (6-tert-butyl-4-methylphenol), 2,2'-methylenebis (6-terL-butyU-ethylphenol),

2,2'-methylene-bis- [4-methyl-6 («- methylcyclo-

hexylj-phenol], U-bis- (5-tert-butyl-4-hydroxy-2-methyl-

phenyl) butane, 2,2-bis- (5-tert-butyl-4-hydroxy-2-methyl-

phenyl) butane,

2,2-bis- (3,5-di-tert-butyl-4-hydroxyphenyl) propane, l, l, 3-tris- (5-tert-butyl-4-hydroxy-2-methyl-

phenyl) -bUan,

2,2-bis- (5-tert, -butyl-4-hydroxy-2-methylphenyl) -

4-n'dodecylmercapto-butane _s IJ, 5,5-tetra- (5-tert-butyl-4-hydroxy-2-methyl phenyl) pentane, Ethylene glycol-bis- [3,3-bis- (3'-tert-butyl-4'-hy-

droxyphenylj-butyrate], 1,1 -Bis- (3,5-dimethyl-2-hydroxyphenyl) -

3- (n-dodecylthio) butane and 4,4'-thio-bis (6-tert-butyI-3-methylphenol), in 1,3,5-tri- (3,5-di-tert-butyI-4-hydroxybenzyl) -

2,4,6-trimethylbenzene, 2,2-bis- (3,5-di-tert-butyI-4-hydroxybenzyl) -

dioctadecyl malonate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate and

S ^ -Di-tert-butyM-hydroxybenzyl-phosphonic acid-

diethyl ester, Amides of 3- (3,5-di-tert-buty1-4-hydroxyphenyl) -

propionic acid, like 2 »l, 3,5-tris- (3,5-di-tert-butyl-4-hydroxyphenyl-

propionyl) -hexahydro-a triazine, N, N'-di- (3,5-di-tert-butyl-4-hydroxyphenyl-

propionyl) hexamethylenediamine. Esters such as 3- (3,5-di-tert-butyI-4-hydro :: yphenyl) -.'-, propionic acid with methanol, ocfadecanol,

1,6-hexanediol, ethylene glycol, thiodiethylene glycol, neopentyl glycol, pentaerythritol,

Tris-hydroxyäthylisocyanuraUdiphenolische

Spirodiacetals or jo spirodiketals, such as 2,4,8,10-tetrooxaspiro- [5,5] -un decane that through in the 3 and 9 positions

phenolic radicals, such as 3,9-bis (3,5-di-tert-butyI-4-hydroxyphenyl) -

2,4,8,10-tetraoxaspiro- [5,5] -undecane and j-, 3,9-bis- [l, l-dimethyl-2- (3,5-di-tert-butyl- 4-hydroxyphenyl) ethyl] -2,4Ä10-tetraoxa- spiro- [5 ^] - undecane.

Are particularly preferred

1,3,5-tri- (3,5-di-tert-butyl-4-hydroxybenzyl) -

2,4,6-trimethylbenzene, Pentaerythritol tetra-t3- (3 ^ -di-tert-butyl-4-hy-

droxyphenyl) propionate], r, ^ - (3,5-di-tert-butyl-4-hydroxyphenyl) -propion-

acid n-octadecyl ester, Thiodiethyleneglycol-j? - (4-hydroxy-3 ^ -di-tert.-

butylphenyl) propionate, 2,6-di-tert-butyl-4-methyl-phenol and 3,9-bis- [1,1-dimethyl-2- (3,5-di-tert-butyl- 4-hydroxyphenyl) ethyl] -2,4ÄlO-tetraoxa-

spiro [5 ^] - undecane and 2,2'-methylenebis (6-tert-butyl-4-ethylphenol).

The phenolic antioxidant can according to the invention in amounts of about 0.0f> up to about 1.0 part per 100 parts of graft copolymer can be used.

The preparation of the used according to the invention

bo Phosphite Lt explained in the examples.

Example !

g amalgamated zinc with a solution of 200 ml concentrated hydrochloric acid in 300 ml of water, 5 _h and a 25 percent solution of 72 g (0.29 Mo!) 4-methyl-2-ncnanoylphenol admixed in ethanol. The mixture is refluxed and stirred for 9 hours, then 200 ml of toluene are added and the mixture is allowed to cool

calmly. After cooling, the organic phase is separated off, washed with water, filtered and evaporated. The residue is distilled. It will be 57% d. Th. 4-Methyl-2-n-nonylphenol obtained.

B e i s ρ i e I 2

Example 1 is made with 80 g (0.29 mol) of 4-methyl-2-dodecanoylphenol repeated. The yield of 4-methyl-2-dodecylphenol is 56% of theory. Th.

Example 3

83 g of phenol are removed by azeotropic distillation of water, then heated to 155 ⁰ C. and partly under argon as a protective gas with 0.83 g Aluminiumgranuiat. When the evolution of hydrogen has ceased, the temperature is reduced to 145 ° C. and 50 g of I-nonene lanysam are added. The reaction mixture is heated and stirred for 6 hours at 145 to 150 ° C. Excess phenol and unreacted 1-nonene are then removed under reduced pressure The residue is washed neutral against litmus with 5 percent hydrochloric acid and then with water. Distillation of the residue gives 30 g (34% of theory: 93% conversion) of a clear, colorless liquid with a boiling point of 94 ° C./133 pascals The product consists of more than 98% o- (1-methyl-octyl) -phenol.

Example 4

Example 3 is repeated with 1-octene. The product obtained is a clear, water- ^{white liquid with a boiling point of 100 to 107 c} C / 3.3 to 23.9 Pa, 93% of which consists of o- (1-methylheptyl) phenol. The yield is 76% of theory. Th. "

Example 5

Example 3 is repeated with propylene trimer instead of 1-nonene. The product is a clear, water-white liquid with a bp. 105 to 110 ^c C / 33.2 Pa. The compound is obtained in 39 percent yield. It consists of 88% o-nonylphenol.

Example 6

Example 3 is repeated with diisobutylene instead of 1-nonene. It will be in 45 percent yield get a clear, water-white liquid, which is 89% consists of o-octylphenol.

A general manufacturing specification for the phosphites is given below:

1.0 mol of the o-alkylphenol is slowly added at 55 "C. with 0.30 mol of phosphorus trichloride. The reaction is initially exothermic. Later, the supply of heat is required to keep the reaction mixture at 55 ^° C. After all of the phosphorus trichloride has been added, the reaction mixture becomes Protective gas is heated to between 80 and 250 ^° C. and kept at this temperature for 23 to 33 hours, after which the reaction mixture is distilled.

The following tris (o-alkylphenyl) phosphites of the general formula are used

Example R '

yield

methyl

methyl

n-nonyl

n-dodecyl

1-methylheptyl

I-methyloctyl

Cyclohexyl

n-butyl

99%
99%
99%
41%
99%
99%

η a <- ■ - ■ produced using this process:

The purity of the products obtained is 33 bis 99%.

The hydrolytic stability of these tris (o-alkylphenyl) phosphites is determined in aqueous tetrahydrofuran. A 2 percent solution of the phosphite in a mixture of 80 parts of tetrahydrofuran and 20 parts Water is heated to 44 ° C. at a pH of 4.5 over a period of 48 hours Hydrolysis of the phosphite is followed by liquid chromatography.

A technical tris (nonylphenyl) phosphite with 92% p-isomer and 6% o-isomer and 2% of the dinonyl compound is completely hydrolyzed after 140 hours. A corresponding sample of tris (nonylphenyl) phosphite with 88% o-isomer and 12% p-isomer it is only 10% after 140 hours and only closed after 760 hours 50% hydrolyzed. A sample of tris (1-methylheptylphenyl) phosphite with 92% o-isomer and 7% 2,4-isomer is only 50% hydrolyzed after 700 hours.

The hydrolytic stability of the tris (o-alkylphenyl) phosphites used according to the invention in aqueous acidic emulsions is also determined. In this experiment, 10 parts of the phosphite are mixed with a solution of 2.1 parts of an anionic phosphoric acid ester in 34 parts of water. The emulsion obtained is added to 400 parts of water. heated to 55 ^° C. and adjusted to a pH of 2.5 with concentrated hydrochloric acid. This diluted emulsion is left to stand in the cold for 10 hours. The pH is then adjusted to 7 with dilute potassium hydroxide solution and the emulsion is poured into 600 parts of a 5 percent aqueous calcium chloride solution at 85 ° C. The mixture is cooled and extracted with benzene. The benzene extract is dried and evaporated. The oily residue obtained is subjected to liquid chromatography.

Samples of technical grade tris (nonylphenyl) phosphite and tris (o-l-methylheptylphenyl) phosphite are used subjected to this test. The former compound is completely hydrolyzed, the latter compound only 30%.

The effectiveness of the tris (o-alkylphenyl) phosphites used according to the invention as stabilizers for The following experiment demonstrates polymers in a hydrolyzing medium: A solution of 6.25 parts of the phosphite and 1.15 parts of oleic acid becomes a hot solution of 0.55 parts of triethanolamine given in 17 parts of deionized water. The mixture is stirred for 1 minute with a high-speed stirrer mixed. The resulting emulsion is added to 325 parts of a polybutadiene latex, and the mixture is stirred for 12 hours. Then the mixture is at 85 ° C by adding 1.5 percent aqueous sulfuric acid coagulated. The precipitated polybutadiene is filtered off, washed and dried. The dried polybutadiene is in an oven at 100 ° C aged. The time required for a completely brown color to develop is used as a measure of stability

of polybutadiene is used.

Samples of the above-described technical grade tris (nonylphenyl) phosphite (A) and the tris (o-1-methylheptylphenylj-phosphite (B) of Example 9 are made subjected to this test. The results summarized in Table I are obtained.

Table I.

Phosphite

Hours to
Discoloration

A. 100 B. 130 no addition 30th

The superiority of the o-alkylphenyl phosphite is evident.

The effectiveness of the used according to the invention Tris (o-alkylphenyl) phosphites as stabilizers for graft copolymers of the type used according to the invention are demonstrated by the following tests:

A mixture of 5.0 parts of phosphite and 2.0 parts

Bis- (3-ethyl-5-tert-butyl-6-hydroxyphenyl) methane becomes 20 parts of an ABS polymer latex (produced by copolymerizing styrene with acrylonitrile in a polybutadiene latex). There are 1.0 parts Stabilizer (phosphite + phenol) per 100 parts of polymer before. The latex becomes more aqueous with 2 percent strength

Sulfuric acid coagulates. The precipitated polymer is filtered off, washed and dried at 50.degree. The dried polymer is pressed into disks 0.30 to 0.38 mm thick and 38 mm in diameter. ^{These panes are heated to 150 °} C. in a hot air oven until they change color and cracks appear in the surface. The time is determined and used as a measure of the effectiveness of the phosphite stabilizers. The results are summarized in Table II.

Table II

Hours to
Discoloration and
RiO formation

Sample phosphite

1 product of example 9 6

2 Tris- (nonyipnenyi) -phosphii, 4 88% o-isomer, 11% p-isomer

3 tris (o-tert-butylphenyl) -2 phosphite

4 no addition 1

Further additives and processing aids can be incorporated into the molding compositions of the invention, including UV stabilizers, antistatic agents, Fillers, pigments, lubricants and mold release agents.

Claims (1)

Patent claims: 1. Heat-stabilized molding compounds based on graft polymers made from graftable, rubber-like stock polymers based on dienes and side branches made from copolymers based on aromatic monovinylidene compounds and olefinically unsaturated nitriles or esters by containing a mixture of tris (alkylphenyl) phosphites with