FI62321B - STABILIZER FORMMASSOR AV POLYOXIMETYLENER - Google Patents

Description

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Federal Republic of Germany Förbundsrepubliken Tyskland (DE) P 2301351-6 (71) Hoechst Aktiengesellschaffc, Postfach 80 03 20, 6230 Frankfurt (Main) 80, Federal Republic of Germany Förbundsrepubliken Tyskland (DE) (72) Ernst Wolters, Frankfurt / Main, Hein / Main , Frankfurt / Main,

Karlheinz Burg, Langenhain / Taunus, Gunter Sextro, Naurod / Taunus,

Federal Republic of Germany-Förbundsrepuhliken Tyskland (DE) (7U) Oy Kolster Ab (5U) Stabilized moldings from polyoxymethylene - Stabiliserande form-massor av polyoximetylener

Polyoxymethylene, i.e. stabilization of formaldehyde or cyclic oligomers of formaldehyde, e.g. trioxane, homo- or copolymers against the effects of heat and oxygen by adding stabilizers.

It is further known to stabilize the polyoxymethylenes in masses by adding a stabilizer system containing l) 0.05-U% by weight of polyoxymethylene, based on the formula R1

HO-yf \ - (CH2) -CO-O

compounds according to r 2 n I *, in which R 1 represents an alkyl residue having 1 to 6 carbon atoms, R 8 represents a hydrogen atom or an alkyl residue having 1 to 6 carbon atoms, A represents a 2 to 6 aliphatic hydrocarbon residue having 1 to 12 carbon atoms , m is zero or an integer from 1 to 6 and n corresponds to the valence of A and 2) from 0.01 to 3% by weight of polyoxymethylene, based on alkaline earth salts and / or alkaline earth metal hydroxides of carboxylic acids containing 10 to 20 carbon atoms (DE- application publication 2 0 ^ 3 ^ 96).

The present invention relates to a stabilized polyoxymethylene pulp, the stabilizer combination of which consists of (a) 0.05-U by weight of phenolic compounds, (b) 0.01-3 by weight of # alkaline earth salts of carboxylic acids, and (c) optionally 0.01 to 1 by weight of # 1 in 1 stabilizer, and wherein the phenolic compounds (component a) have the formula R 1 (CH 2 -CO-O- a

Ea n is an alkyl group having 1 to 6 carbon atoms, Rg is hydrogen or an alkyl group having 1 to 6 carbon atoms, A is a 2-6-valent aliphatic hydrocarbon group having 1 to 12 carbon atoms, m is 0 or an integer 1 -6, and n corresponds to the valence of A. The stabilized form mass according to the invention is characterized in that the alkaline earth salts of carboxylic acids (component b) are additional alkaline earth salts of aliphatic mono-, di- or tricarboxylic acids having 2 to 9 carbon atoms or araliphatic or aromatic carboxylic acids having 7 to 9 carbon atoms, (component c) compounds of formula are used

NC-NH-C-NH-R

lt

NH

wherein R is hydrogen, a cyano group, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 6 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, wherein said alkyl, cycloalkyl or aryl groups may be substituted with 1, 2 or 3 hydroxy groups.

3 62321

The stabilizer combination used according to the invention cannot be removed from the polyoxymethylene by conventional solvents and does not diffuse from the polyoxymethylene when heated, so that the molding compositions according to the invention are particularly suitable for use at elevated temperatures or in combination with solvents. The stabilizers used are colorless and also color polyoxymethylene when exposed to heat, light or alkaline substances for a long time with relatively little or no exposure.

A particular advantage of the inert molding compounds of the invention is that they are obtained by injection molding better than molding bodies from known molding compounds.

"Mechanical strength and coefficient of friction are also improved by the effect of a flawless surface. This is an advantage in the production of technical parts that are exposed to high loads, and also in the production of maintenance-free bearings.

According to the invention, component a) is preferably an ester of 7 to 9 carbon-containing araliphatic or aromatic monocarboxylic acids and a straight-chain or branched aliphatic dihydric alcohol, the aromatic ring of which is substituted in the it position by a hydroxyl group and in the 3- or 3- and 5-positions by 1-U with an aliphatic alkyl residue containing carbon atoms, e.g. β- (3-tert-hatyl-4-hydroxyphenyl) -pentanoic acid, N- (3-methyl-5-tert-butyl-β-hydroxyphenyl) propionic acid, 3,5-di tert. -butyl-U-hydroxybenzoic acid, (3,5-ditert-butyl-U-hydroxyphenyl) -acetic acid, [3- (3,5-di-tert-butyl-N-hydroxyphenyl) -propionic acid or ( diisopropyl-4-hydroxy-phenyl) -acetic acid ester of ethylene glycol, propanediol (1,2), propanediol (1,3), butanidium (1,1 *) , hexanediol (1,6), decanediol (1,10), 1,1,1-trimethylethane or pentaerythritol.

Suitable alkaline earth metal salts are in particular 1) saturated or unsaturated aliphatic mono-, di- or tricarboxylic acids having 2 to 9, preferably 3 to 7, carbon atoms, for example acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, heptanoic acid, heptanoic acid, capric acid, capric acid , malonic acid, succinic acid, glutaric acid, adipic acid, cork acid, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, angelic acid and tiglinic acid Mg, Ca-,

Sr and Ba salts, or 2) the corresponding salts of araliphatic carboxylic acids having 7 to 9 carbon atoms, e.g. phenylacetic acid and cinnamic acid, or 3) the corresponding salts of aromatic carboxylic acids having 7 to 9 carbon atoms, e.g. benzoic acid.

Particularly suitable are the alkaline earth metal salts of mono-, di- or tribasic hydroxycarboxylic acids having 2 to 9, preferably 3 to 7, carbon atoms, e.g. the calcium and magnesium salts of lactic acid, mandelic acid, malic acid, citric acid and hydroxypivalic acid and salicylic acid.

"1 k 62321

Suitable additional stabilizers (component c) which may be used are, for example, cyanoguanidine, N-cyano-N'-guanidine, N-cyano-N'-ethylguanidine, N-cyano-N'-isopropylguanidine, N-cyano-N'-tert-butyl -guanidine, N-cyano-N'-dodecylguanidine, N-cyano-N * -cyclohexylguanidine, N-cyano-N'-benzylguanidine, N-cyano-N'-phenylguanidine, N-cyano-N'-hydroxymethylguanidine, N-cyano-N '- (2-hydroxyethyl) -guanidine or N, N'-dicyanoguanidine.

In addition, the shaped compositions may contain known light stabilizers, such as Bent sophenone, acetophenone or triazine derivatives. Other conventional additives such as colorants, pigments, reinforcing agents and fillers may also be added.

The stabilizers may be mixed as a powder with commercial mixers, such as dry mixers, in polyoxymethylene, or they may be dissolved in a suitable solvent, e.g. methanol, acetone or methylene chloride, and added to the polymer by mixing. The solvent is then evaporated off.

Polyoxymethylenes which can be stabilized according to the invention are homopolymers of formaldehyde or a cyclic oligomer of formaldehyde, e.g. trioxane, the hydroxyl end groups of which are chemically protected by esterification or etherification with preferably an oxyalkylene group containing 2-k adjacent carbon atoms. The proportion of monomer in the copolymers is 0.1 to 50, preferably 0.1 to 15% by weight.

As compounds suitable for copolymerization with formaldehyde or a cyclic oligomer of formaldehyde, preferably trioxane, cyclic ethers and / or cyclic acetals and / or linear polyacetals are used in particular. Particularly suitable are cyclic ethers of 3 to 5 ring members, in particular epoxides, further cyclic acetals having 5 to H, preferably 5 to 6 ring members, in particular cyclic formalities of O, W diols having 2 to 8, preferably 2 to U carbon atoms in the chain and having the carbon chain can be interrupted by an oxygen atom at two carbon atoms, as well as linear polyformals.

Particularly suitable are compounds of the formula ch2- (chr) x- / o- (ch2) z7y-o, wherein R represents a hydrogen atom, an alkyl radical having 1 to 6, preferably 1 to 3 carbon atoms, which may be substituted by 1 to 3 halogen atoms. -la, preferably a chlorine atom, an alkoxymethyl residue containing 2 to 6, preferably 2-H carbon atoms, a phenyl residue or a phenoxymethyl residue, x is an integer from 1 to 3, where y is zero, y is an integer from 1 to 3, where x is zero and z is 2 and 5 62321 z is an integer from 3 to 6, preferably 3 or 1 *, where x is zero and y is one.

Examples of cyclic ethers are ethylene oxide and epichlorohydrin and propylene oxide, styrene oxide, cyclohexene oxide, oxacyclobutane, phenylglycidyl ether and butanediol glycidyl ether and 1,3-dioxo-trioxane and 1,3-dioxolane, for example 1,3-dioxol, -1,3-dioxolane, 1,3-dioxonane and 1,3-dioxacycloheptene- (5).

The polyoxymethylenes used according to the invention are macromolecular; their viscosity number (RSV) measured at 10 ° C in a 0.5% by weight solution of the polymer in Ύ-butyrolactone containing 2% by weight of diphenylamine as a stabilizer is 0.3-3.0, preferably 0.5-2 dl / g . The crystallite melting point of the above polyoxymethylenes is in the range of 150 to 180 ° C.

The molding compositions according to the invention can be treated by all methods suitable for thermoplastics, such as, for example, injection molding, extrusion molding, blow molding, melt spinning or deep drawing. They are suitable for the manufacture of semi-finished and finished articles, such as moldings, e.g. strips, rods, brushes, fibers, sheets, films, foils, tubes or hoses, and household articles, e.g. basins and plates and machine parts, e.g. housings or gears. The molding compositions according to the invention are particularly suitable for the production of injection-molded articles with openings (grooves) or cavities which make it difficult to melt the molten mass into a mold.

examples:

Examples 1-12 and Comparative Examples A-C

The acetylated formaldehyde homopolymer (RSV 0.90 dl / g) was thoroughly mixed with 1.0 g of tetrakis-N - 6- (3,5-di-tert-butyl-.alpha.-hydroxyphenyl) -propionyloxymethyl with 0.2% by weight of magnesium and the magnesium salts of the acids shown in Table 1 and granulated in a commercial press, the weight loss of the dried granulate was determined to be 1 * 5 resp. After heating the sample for 120 minutes in air at 230 ° C. Further, 2.5 mm thick, round sample plates with a diameter of .5 cm were prepared from the granulate before and after heating for 30 minutes in a closed mold at 230 ° C; the plates were then determined to be yellowed with a color difference meter (Colormaster, manufactured by Manufacturing, Engineering and Equipment Corp., Hatboro, Pa., USA) (yellow value).

Further, teardrop-shaped plates were prepared from the granulate using a commercial injection molding machine (pulp temperature 200 ° C, tool temperature 80 ° C, injection pressure and afterpressure 1 * 5 bar *, average piston speed), which are particularly suitable for examining surface defects that may have formed during the injection operation. In a mold made according to the invention, 1.0% by weight of tetrak 3.5 "di-tert. -butyl-1 * -hydroxyphenyl) -propion o-6 62321 from a mixture of a formulation mass stabilized with a mixture of 0.2% by weight of the magnesium salt of 0.2% malic acid, no surface defects were observed (cf. 1), while a molding made of a mixture of 1.0% by weight of tetrakis-N - (3,5-di-tert-butyl-hydroxyphenyl) -propionyloxymethylmethane and 0.2% by weight of calcium stearate has clear surface grooves (cf. Fig. 2). The results of the experiments are shown in Table 1.

table 1

Eg Weight loss of magnesium salt after Yellow value Acid of shaped parts) .c · Ton · surface quality 45 min. 120 min. before jal%% A Stearic acid 0.82 3.3 0.8 12.2 strongly surface grooves B Castor oil acid 0.66 2.5 1.6 14.0 "C Arachinic acid 0.72 2.9 3.5 23 .0 ”1 Acetic acid 0.80 3.1 0.4 18.9 no surface grooves 2 Propionic acid 0.6l 2.8 1.8 17.4" 3 Caproic acid 0.92 3.5 0.4 13.8 "4 Pelargonic acid 0.84 3.1 0.1 12.2 "5 Lactic acid 0.75 2.9 0.7 14.9" 6 Malic acid 1.05 3.7 1.2 18.3 "7 Hydro xypivalic acid 1 .22 4.1 1.4 25.0 "8 Malonic acid 1.17 4.3 0.1 10.0" 9 Adipic acid 0.97 3.5 0.1 11.4 "10 Salicylic acid 1.01 3.9 0.4 25.0 "11 Cinnamic acid 1.05 4.0 1.8 17.1" 12 Mandelic acid 0.91 3.4 0.0 15.2 "

Example 13 and Comparative Example D

The copolymer containing 98% by weight of trioxane and 2% by weight of ethylene oxide (RSV 0.82 dl / g) was thoroughly mixed with 0.5% by weight of 1,6-bis-β- (3,5-di-tert-butyl). -4-Hydroxyphenyl) -p-propionyl-oxy-hexane and 0.1% by weight of an alkaline earth salt and granulated in a commercial press. The weight loss of the dried granulate was determined after heating the sample for 120 minutes at 230 ° C in air. The yellow value before and after heating for 30 minutes was further determined according to Examples 1-12.

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The granules were further compressed under the conditions mentioned in Examples 1-12 into valve plates, the surface properties of which were examined. The surface of the valve plates made of the molding compound according to the invention was smooth and flawless (cf. Fig. 3), while the valve plates made according to Comparative Example D had fine cracks in the vicinity of the opening, which made the valve plates unusable (cf. Fig. H).

Table 2

Example Alkaline earth salt Weight loss Yellow value (%) “before after D Calcium ricinoleate 2.8 1.1 17 * 1 13 Calcium! lactate 2.6 0.8 15.8

Example lU

The copolymer containing 98% by weight of trioxane and 2% by weight of ethylene oxide (RSV-Ervo 0.82 dl / g) was thoroughly mixed with 0.5% by weight of 1,6-his - // S- (3,5-di-tert .- butyl-1 * -hydroxyphenyl) -propionyloxy-7-hexane, 0.1% by weight of calcium lactate and 0.02% by weight of cyanoguanidine and granulated in a commercial press. The weight loss of the dried granulate after heating for 120 minutes in air at 230 ° C was determined to be 2.2%. The yellow values before and after heating for 30 minutes were further determined according to Examples 1-12. They were 0.6 and 12, k, respectively.

The surfaces of the shaped bodies made of granulate were smooth and without surface grooves.

Claims (5)

8 62321 A stabilized polyoxymethylene form pulp, the stabilizer combination of which consists of (a) 0.05 to ** by weight of phenolic compounds, (b) 0.01 to 3 by weight of alkali metal salts of carboxylic acids, and (c) optionally 0 , 01-1 by weight of an additional stabilizer and wherein the phenolic compounds (component a) have the formula HO (CH 2 B2 * wherein R 1 is an alkyl group having 1 to 6 carbon atoms, R 2 is hydrogen or an alkyl group having 1 to 6 carbon atoms, A is a 2-6 valence aliphatic hydrocarbon group having 1 to 12 carbon atoms, m is 0 or an integer from 1 to 6, and n corresponds to the valence of A, characterized in that the alkaline earth metal salts of carboxylic acids (component b) are aliphatic, 2- Alkaline earth metal salts of mono-, di- or tricarboxylic acids having 9 carbon atoms or araliphatic or aromatic carboxylic acids having 7 to 9 carbon atoms, and that compounds of the formula NC-NH-C-NH-R are used as possible additional stabilizers (component c) tt NH where R is hydrogen, a cyano group, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 6 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, wherein said alkyl, cycloalkyl or aryl groups may be substituted with 1, 2 or 3 hydroxyl groups. Molding according to Claim 1, characterized in that it contains, as component b), calcium or magnesium salts of saturated or unsaturated aliphatic carboxylic acids having 2 to 9 carbon atoms. 62321 Molding according to Claim 1, characterized in that it contains calcium lactate or magnesium lactate as component b), 1 *. Molding according to Claim 1, characterized in that it contains cyanoguanidine as component c). 1, Stabilized press pulp from polyoxymethylene with a stabilization combination, including a mixture of polyoxymethylenes, (a) 0.05-U weight- # phenolic formulation (b) 0.01-3 weight- $ 5 jordalkalisalter av carboxylsyror och (c) eventuellt 0.01--1% of the compounds of the stabilization form, and in which the phenolic formulation (component a) is of the form H0-- c0- ° ~ n color is an alkyl group with 1-6 cholatomers, R2 is a substance or an alkyl group. 1-6 cholaters, A to 2-6-aliphatic flask group having 1 to 12 cholaters, 0 to 0 or 1 to 6 times and 1-6 octons in the valence of A, the same as in the carboxylic acid ( component b) is an alkali metal or aliphatic mono-, di- or tricarboxylic acid with 2-9 cholaters or an aliphatic aliphatic or araliphatic or aromatic matricarboxylic acid with 7 ~ 9 cholaters, and optionally other formulation stabilizers (component c) NC-NH-C-NH-R ft NH color R är Väte, en cyangrupp, en alkylgrupp from 1 to 12 cholatomers, in which the cycloalkyl group is from 6 to 12 cholatomers or aryl groups, in the case of ζ -12 cholatomers, in which the alkyl, cycloalkyl or aryl groups are optionally substituted by 1,2 to 3 hydroxyl groups.