FI60226C - STABILIZER PRESSMASSOR AV POLYOXIMETYLEN - Google Patents

Description

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Federal Republic of Germany-Förbundsrepubliken

Germany (DE) P 22 ^ 3323- ^ (71) Hoechst Aktiengesellschaft, 6230 Frankfurt / Main 80, Federal Republic of Germany - Förbundsrepubliken Tyskland (DE) (72) Ernst Wolters, Frankfurt / Main, Heinz Schmidt, Frankfurt / Main,

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) (7 ^) Oy Kolster Ab (5! +) Stabilized polyoxymethylene molding compounds - Stabiliserade pressmassor av polyoximethylen

It is known that polyoxymethylenes, i.e. homopolymers or copolymers of formaldehyde or cyclic oligomers of formaldehyde, for example trioxane, are stabilized against the action of heat and oxygen by adding stabilizers.

Examples of stabilizers are phenols, amines, amides, amidines, hydrazines, ureas, thioureas and polyamides. The stabilizing effect of these substances is due to their ability to bind aldehydes and their derivatives formed by thermal cleavage of the chain, to protect the active centers present in the polymers and thus to prevent depolymerization.

The potency of said substances is very different. The stabilizing effect of hydrazine, urea or thiourea derivatives against heat or oxygen is negligible. Although amine stabilizers are good antioxidants, they cause brownox-black staining of polyoxymethylenes. Some of the known phenol-based stabilizers also cause discoloration, others readily diffuse out of or dissolve out of the polymers, whereby the stability of the polymers is reduced when exposed to heat and / or in contact with solvents.

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It is also known to use various hydroxyphenylalkanoic acid compounds as stabilizers for organic substances, in particular polyolefins (cf. DE 1 163 017 and 1 201 3 ^ 9, DE 1 286 0 ^ 1, BE 636 2 ^ 1). and NL publication 6 808 9 ^ 6). It is also known to use hydroxyphenylalkanoic acid compounds for the stabilization of polyoxymethylenes (cf. FR 1 U89 Ul ^) ·

Also known are stabilized compression masses made of polyoxymethylenes which contain 1) 0.05% by weight, based on the amount of polyoxymethylene, of the compounds of the formula rn

HO _ / (OHo) -C0-0- A

> = / ”E2 n wherein R1 represents an alkyl residue having 1 to 6 carbon atoms, R1 represents a hydrogen atom or an alkyl residue having 1___6 carbon atoms, A two hexavalent straight-chain or branched aliphatic hydrocarbon radicals having 1 to 12 carbon atoms, m zero or an integer of 1 to 6 and n corresponds to the valence of A, and 2) 0.01 to 3% by weight, based on the amount of polyoxymethylene, of alkaline earth hydroxides of carboxylic acids having 10 to 20 carbon atoms ('.rrt. DE application publication 2 0H3 1 * 98).

The invention relates to stabilized polyoxymethylene compression masses which contain a) 0.05 · by weight, based on the amount of polyoxymethylene, of the compounds of the formula RK_

HO _ / v (OHg ^ -CO-O- A

R 2 n wherein R 1 is an alkyl group having 1 to 6 carbon atoms, R 6 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, A is a 2 to 6 aliphatic hydrocarbon group having 1 to 12 carbon atoms and m is zero or an integer from 1 to 6, and n corresponds to the valence of A and 3 60226 b) 0.01 .., 3% by weight, based on the amount of polyoxymethylene, of the alkaline earth metal salts of aliphatic carboxylic acids.

The invention is characterized in that the carboxylic acids are monocarboxylic acids having 22 to 36 carbon atoms.

By using the long-chain or alkaline earth metal salts of carboxylic acids according to the invention, the cleavage of polyoxymethylenes at a higher than normal temperature and the tendency of the polymers to discolor are reduced more effectively than when using 10 ...

Alkaline earth metal salts of carboxylic acids of 20 carbon atoms.

The stabilizer combination used according to the invention does not dissolve in polyoxymethylene under the action of conventional solvents and does not diffuse out of the polyoxymethylene under thermal loading, so the compression masses according to the invention are particularly suitable for use at higher than normal temperatures or in contact with solvents. The stabilizers used are colorless and do not stain the polyoxymethylenes when they are exposed to Olana for a long time under the influence of heat, light or alkaline substances, or the effect is only relatively small.

Of the esters of ring-substituted araliphatic or aromatic carboxylic acids used in the stabilizer combination within the scope of the invention, esters prepared from araliphatic or aromatic mono-carboxylic acids having 7 to 13 carbon atoms, preferably 7 to 9 carbon atoms, is a hydroxyl group as a substituent and an aliphatic alkyl residue having 1 to U carbon atoms in the 3- or 3- and 5-positions, and straight-chain or side-chain, aliphatic, dihydric or tetravalent alcohols, e.g. -butyl-U-hydroxyphenyl) -pentanoic acid [3- (3-methyl-5-tert-butyl-U-hydroxyphenyl) -propionic acid, 3,5-ditert-butyl-U-hydroxy-benzoic acid, (3, 5-di-tert-butyl-1-hydroxyphenyl) -acetic acid, 3- (3,5-di-tert-butyl-hydroxyphenyl) -propionic acid or (3,5-diisopropyl-4 -hydroxyphenyl) -acetic acid esters of ethylene glycol, propanediol (1,2), propanediol (1,3), butane with nidiol (1,1 *), hexanediol (1,6), decanediol (1,10), 1,1,1-trimethylolethane or pentaerythritol.

Particularly suitable alkaline earth metal compounds are the magnesium, calcium, barium and strontium salts of saturated or unsaturated aliphatic carboxylic acids having 22 to 36 carbon atoms. Carboxylic acids may also have hydroxyl groups as substituents. Examples of saturated aliphatic carboxylic acids are behenic acid, lignoseric acid, serotinic acid, montanic acid, melicic acid, psylic acid and psyllastearyl acid, suitable unsaturated aliphatic carboxylic acids, for example erucic acid, for example Particularly preferred are the calcium and magnesium salts of behenic acid and montanic acid.

If necessary, the compression compositions according to the invention may also contain other stabilizers, e.g. known light stabilizers such as Bent sophenone, 4,602,26 acetophenone or triazine derivatives. Other conventional additives such as dyes, pigments and fillers can also be added to the mixtures.

The stabilizers are added to the polyoxymethylene as powders on commercially available mixers, for example dry mixers, or they are first dissolved in a suitable solvent, e.g. methanol, acetone or methylene chloride, and then the solution is added to the polymer with stirring. The solvent is then evaporated off.

Polyoxymethylenes which can be stabilized according to the invention are homopolymers of cyclic oligomers of formaldehyde or formaldehyde, e.g. trioxane, the hydroxyl end groups of which are blocked by chemical changes, e.g. the lens chain has an oxyalkylene group having at least two, mainly two to four, adjacent carbon atoms. The proportion of comonomer in the copolymer is 0.1-50, mainly 0.1-15% by weight.

As compounds suitable for copolymerization with formaldehyde or cyclic oligomers of formaldehyde, in particular trioxane, cyclic ethers and / or cyclic acetals and / or linear polyacetals are used in particular. Particularly suitable are cyclic ethers having 5-5 ring members, mainly epoxides, further cyclic acetals having 5-11, mainly 5-8 ring members, in particular β-diols having 2-8, mainly 2- 4 carbon atoms, cyclic formalities whose carbon chain may be interrupted by an oxygen atom at intervals between two carbon atoms, as well as linear polyform paints.

Particularly suitable are compounds of the formula CH2- (CHR) x- [O- (CH2) 2] y-O in which R represents a hydrogen atom, an alkyl radical having 1-6, in particular 1-5 carbon atoms and which may have as substituents 1 to 5 halogen atoms, mainly a chlorine atom, an alkoxymethyl residue having 2 to 6, mainly 2 to 4 carbon atoms, a phenyl residue or a phenoxymethyl residue, x an integer from 1 to 5, where y is zero, y an integer from 1 to 5 »where x is zero and z is 2, and z corresponds to an integer from 5 to 6, closest to 5 or 4 »where x is zero and y is 1.

Examples of cyclic ethers are ethylene oxide and epichlorohydrin and propylene oxide, styrene oxide, cyclohexene oxide, oxycyclobutane, phenylglycidyl ether and butanediol diglycidyl ether, and 1,5-dioxane is used as cyclic formalin, for example 1,5-dioxane, chloromethyl-1,5-dioxolane, 1,5-dioxonane and 1,5-dioxacycloheptene- (5), linear polyacetals are, for example, polydioxolane and polydioxepane.

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The polyoxymethylenes used according to the invention are high molecular weight, their viscosity numbers (RSV; red.), Measured at 140 ° C in a 0.5 wt. between 0.3-5.0 mainly between 0.5-2 dl / g. The melting point of the above-mentioned polyoxymethylene crystallites is between 150 and 180 ° C.

The stability test of polyoxymethylenes against heat and oxidation is carried out by determining the weight loss of the granulate sample after 120 minutes at 230 ° C in air. To determine the color values and color fastness of polyoxymethylenes, 2.5 mm thick, round color model plates with a diameter of 4.5 cm are prepared from individual sample granules in a closed mold at 230 ° C before heating and after heating for 30 minutes, their yellow values are measured and compared in a differential colorimeter. Colormaster, Manufacturing, Engineering and Equipment Corporation, Hat-boro, Pensylv.). In addition, color stability can also be determined from color sample plates of the above-mentioned length prepared from sample granules after storage for 10 days at 120 ° C in a circulating air drying oven.

The molding compositions according to the invention can be processed by all conventional processing methods for thermoplastic active materials, e.g. by injection molding, extrusion, blow molding, melt spinning or deep drawing. They are suitable for the manufacture of semi-finished and finished parts such as moldings, e.g. strips, rods, brushes, wires, fibers, plates, films, films, tubes or hoses, as well as household articles, e.g. plates or buckets and machine parts, e.g. housings or gears.

Examples 1-9

The copolymer prepared from 9% by weight of trioxane and two by weight of 1,3-dioxolane (RSV 0.92 dl / g) is thoroughly mixed with 0.5% by weight of 1,6-bis- [ p- (3,5-di-tert-butyl-4-hydroxy-phenyl) -propionyloxy] -hexane and, with the amounts indicated in Table 1, alkaline earth salts and granulated on a commercial extruder. The weight loss is determined from the dried granules. Yellow values are determined before and after 30 minutes of heating from the color model plates * The results of the experiments are summarized in Table 1 (Examples A and F are comparative experiments).

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table 1

Eg Alkaline earth salt Amount- Weight- Yellow value (weight- $) loss' '' before after A Calcium stearate 0.1 7.8 3.8 25 E "0.5 6.2 4.3 28 C" 1 .0 4.2 6.1 52 I) Calcium ricin oleate 0.1 4.5 4.3 29 E "0.5 4.1 6.0 58 F" 1.0 5.8 8.1 45 1 Calcium behenate 0.1 2.8 0.6 16 2 "0.5 2.6 0.9 18 3" 1.0 2.1 0.8 18 4 Magnesium montanate 0.1 2.9 0.2 10 5 "0, 3 2.3 1.0 12 6 "1.0 1.9 1.5 13 7 Calcium montanate 0.1 2.5 1.0 19 3" 0.3 2.3 0.5 18 9 ”1.0 1 , 8 0.8 22

Examples 10-14

The acetylated formaldehyde homopolymer (RSV value: 0.85 dl / g) is thoroughly mixed with the stabilizer components listed in Table 2 in a high speed mixer (about 1500 rpm) and then granulated with a commercial extruder. After granulation and drying, the weight loss of the samples is determined. Yellow values are determined from color sample plates before and after heat treatment. The results of the experiments are shown in Table 2 (Examples G-J are comparative experiments).

7,

Table 2 60226!

Example Stabilizer combination .Quantity Weight- Yellow value (jjaino-Ja) loss after enner (£) JOnin 10 23O C day

1 20 ° C

G 1,1,1-tris-N- (3,5-di-tert-0.7 6.0 U, 233 32 butyl-t-hydroxyphenyl) -propionyloxymethyl] -, ethane "";

calcium stearate 0.2 L

H tetrakis [5- (3,5-di-tert-2 1.0 2.9 3.7 32 36 butyl-tert-hydroxyphenyl) -propionyloxymethyl] methane calcium racrate 0.2 J 1.6 -bis (-13.5-tert-tert.-0.5 3.3 7.5 32 butyl (n-hydroxyphenyl) -propionyloxy) 7'-hexane; calcium uraricin oleate 0.2 10 1, 1,1-tri s / ^ 3 - ^ 3 »5-hi-tert. - 0.5 2.2 0.8 10 21 butyl-4-hydroxyphenyl) -propionyloxymethyl] /-! and Denmark

Magnesium montanate 0.1 11 1,1,1-tris-13 * 5-cti-tert-0,5 2,5 1,3 12 10 butyl - (4-hydroxyphenyl) -propionyloxymethylated -Bis-α - (3,5-cli-tert-0.5 -6.2-butyl-tert-hydroxyphenyl) -propionyloxy-hexane magnesium montanate 0.1 13 tetrakis-3 - ( 315-di-ter. - 1,0 1,8 1,7 19 22 butyl (t-hydroxyphenyl) propionyloxymethyl / methane calcium behenate 0,2 l-1,6-bis - (3,5-di -tert.-0.5 2.1 0.5 14 17 butyl-((1-hydroxyphenyl) -propionyl oxy / hydroxy], uni strontium beehia, mp 0.2 8 60226

Examples 15 and 16

The copolymer prepared from 98 wt.% Trioxane and 2 wt.% Ethylene oxide (HSV value: 0.82 dl / g) is thoroughly mixed with the stabilizer combinations listed in Table 5 and granulated with a commercial extruder. The weight gain of the samples is determined from the dried granules. For the stove, the yellow values are determined from the color model plates before and after heating for 30 minutes. The results of the experiments are shown in Table 5 (Examples K and L are comparative experiments).

Table 5

Eg Stabilizer combination Amount Weight-yellow value naino- $ loss before after (*) K 1,6-bis [p- (3,5-di-tert-butyl-4-hydroxyphenyl-0.5 2.8 l .5 16.3 l) -propionyloxy] -hexane calcium ricinoleate 0.1 L tetrakis [[;-( 3,5-di-tert-butyl-4-hydroxyphenyl-1,0 4 * 2 2,7 14 (3H) -propionyloxymethyl] -methane calcium stearate 0.1 15 l, 6-bis [β- (3,5-di-tert-0.5 to 1.8 -1.0 10.0 butyl 4-Hydroxyphenyl) -propionyloxy] -hexane calcium montanate 0.1 16 tetrakis [[- (3,5-di-tert-butyl-4-hydroxy-phenyl) -propionyloxymethyl *] -methane 1.0 2.0 -0.5 8.7 calcium behenate 0.1

Claims (1)

60226 9 Patents: Stabilized polyoxymethylene compression masses containing (a) 0,05. . 1 + by weight-, based on the amount of polyoxymethylene, the compounds of the formula R 1 \ __ HO (0¾) ^ 0-O- wherein R 2 is an alkyl group having 1 to 6 carbon atoms are a hydrogen atom or 1. .. an alkyl group having 6 carbon atoms, A is an aliphatic hydrocarbon group having 2 to 6 carbon atoms of 1 to 12 carbon atoms and m is zero or an integer from 1 to 6, and n corresponds to the valence of A, and b) 0, 01 to 3% by weight, based on the amount of polyoxymethylene, of the alkaline earth metal salts of aliphatic carboxylic acids, characterized in that the carboxylic acids are monocarboxylic acids having 22 to 36 carbon atoms. Pat entkrav: Stabiliserade pressmassor av polyoximetylener innehällande a) 0,05 · .. ^ vikt- #, beräknat pä polyoximetylen mängden, föreningar med formuleln R, 'y_. ; HO - // V- (CH0) -C0-0 A (\ = / 2m R2 n __ color R ^ är en alkylgroup with 1 ... 6 cholatomers, R ^ är en väteatom eller en alkylgrupp med 1 ... 6 kolatomer, A är en 2 ... 6-värd, alipatisk kolvätegrupp med 1 ... 12 kolatomer och m är noll eller ett heltal 1 ... 6 och n motsvarar valensen av A, och b) 0,01 ... 3 vikt- #, beräknat pä polyoximethylen mängden, av jordalkalimetall-salter av alipatiska carboxylsyror, kännetecknat därav, att carboxyl-syrorna utgöres av monocarboxylsyror med 22 ... 36 kolatomer.