JPS6084348A - Stabilized polyoxymethylene forming composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Stabilization of polyoxymethylene, i.e. homo- or copolymers of formaldehyde or cyclic oligomers of formaldehyde, such as trioxane, against the effects of heat and oxygen by adding stabilizers. is publicly known.

In Japanese Patent Publication No. 55-22508, (0.05 to 4 weight based on polyoxymethylene), the following formula (in the above formula, R1 is an alkyl group having 1 to 6 carbon atoms, R2 is Hydrogen atom or alkyl group having 1 to 6 carbon atoms, A#'i divalent to hexavalent aliphatic hydrocarbon group having 1 to 12 carbon atoms, ■ means zero or an integer from 1 to 6 and n corresponds to the valence of A), and (2) a carboxylic acid having 10 to 20 carbon atoms of 0.01 to 3% by weight based on the polyoxymethylene. Stabilized polyoxymethylene molding compositions are described which are characterized in that they contain alkaline earth metal salts and/or alkaline earth metal hydroxides.

The inventors of the present invention have developed the above invention and have discovered a molding composition that has a further improved stabilizing effect. That is,
The object of the invention is (a) o, o5 to 4 weight -1 preferably 0.1 to 2 weight - based on polyoxymethylene, of the following formula (in the above formula, R1 is 1 to 6, preferably ke1 to 4
alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, R2Fi hydrogen atom or #i alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms; having, divalent to hexavalent,
Preferably a divalent to tetravalent straight-chain or branched aliphatic hydrocarbon group, m means zero or an integer from 1 to 6, preferably zero, 1 or 2, and n is A
and (b) an alkaline earth metal salt of a carboxylic acid in an amount of 0.01 to 3% by weight, preferably 0.1 to 2% by weight based on the polyoxymethylene. in a stabilized polyoxymethylene molding composition containing 2 to 9, preferably 6 alkaline earth metal salts of carboxylic acid.
alkaline earth metal salts of aliphatic carboxylic acids having from 7 to 7 carbon atoms or araliphatic or aromatic carboxylic acids having from 7 to 9 carbon atoms, and optionally (C) Polyoxymethylene t-a 0.01
to 1 weight bag of the following formula % formula % (In the above formula, R is a hydrogen atom, a cyano group, 1 to 12,
an alkyl group preferably having 1 to 6 carbon atoms, a cycloalkyl group having 6 to 12 carbon atoms, preferably 6 to 8 carbon atoms, or a cycloalkyl group having 6 to 12 carbon atoms, preferably 6 to 8 carbon atoms; aryl group, in which the above-mentioned alkyl group, cycloalkyl group or aryl group may each be substituted by 1.24 or 3 hydroxyl groups),
The above-mentioned stabilized polyoxymethylene molding composition is characterized in that it contains the following.

Since the combination stabilizer used according to the invention does not dissolve out of the polyoxymethylene by conventional solvents and does not diffuse out of the polyoxymethylene upon thermal loading, the molding composition according to the invention has a or particularly suitable for use in contact with solvents. The stabilizers used are colorless and cause no or only relatively slight discoloration of the polyoxymethylene even under the long-term influence of heat, light or alkaline agents.

A particular advantage of the molding compositions according to the invention is that they can be processed better in injection molding processes, compared to known molding compositions, into molded bodies having a schlieren-free surface. That's the point. Injection molded bodies with a perfectly smooth, glossy surface are obtained from the molding composition according to the invention. Mechanical strength and coefficient of friction are also improved to a certain extent by the striation-free surface. This may be advantageous in the case of industrial parts that are subjected to high loads or in the case of uncontrolled storage.

Particularly preferred among the esters of aromatic aliphatic or aromatic carbon atoms used as component (a) of the combination stabilizer in the present invention are those whose aromatic nucleus is 4
7 to 13, preferably 7 to 9 carbon atoms, substituted in the 3-position by a hydroxyl group and in the 3-position or in the 3- and 5-position by an aliphatic alkyl group each having 1 to 4 carbon atoms. esters of araliphatic or aromatic monocarboxylic acids with straight-chain or branched aliphatic di- to tetrahydric alcohols, such as ω-(3-tert-butyl-4-hydroxyphenyl) -bentanoic acid, β-(3-methyl-5-tert-butyl-4-hydroxyphenyl)-propionic acid 3,
5-di-tert-butyl-4-hydroxybenzoic acid, (3,5
-di-tert-butyl-4-hydroxyphenyl)-acetic acid, β
-(3,5-di-tert-butyl-4-hydroxyphenyl labrobionic acid, also #-1(3,5-diisopropyl-4-hydroxyphenyl)-acetic acid, ethylene glycol, propanediol-(1,2) , propanediol-(1,3), butanediol-(1,4), -.xanediol-(t,6), decanediol-(1°1st, 1,1.1-trimethylolecune or an ester with pentaerydrift.

Alkaline earth gold salts include saturated or unsaturated fatty acid, enanthic acid, caprylic acid and belarcoic acid, having from 2 to 9 carbon atoms, preferably from 3 to 7 carbon atoms; acid,
(2) having 7 to 9 carbon atoms; Particularly preferred are the magnesium-, calcium-, strontium- and barium salts of araliphatic carbonic acids, such as phenylacetic acid C2 and cinnamic acid, or (3) aromatic carboxylic acids having 7 to 9 carbon atoms, such as benzoic acid. suitable.

Particularly suitable are the alkaline earth metal salts of monobasic, dibasic or tribasic oxycarboxylic acids having 2 to 9, preferably 3 to 7 carbon atoms, such as lactic acid, mandelic acid, malic acid. , citric and oxypivalic acids, and the calcium and magnesium salts of salicylic acid.

Preferably, these molding compositions also contain stabilizing aids against the effects of heat and oxygen, such as polyamides, amides of polybasic carboxylic acids such as malonic diamide, urea and poly(N-vinyl lactams). . Particularly suitable stabilizing aids are those having the following formula (% formula %) (in the above formula, R is a hydrogen atom, a cyan group, 1 to 12 atoms,
an alkyl group preferably having from Fil to 6 carbon atoms, a cycloalkyl group having from 6 to 12 carbon atoms, preferably from 6 to 8 carbon atoms, or from 6 to 12 carbon atoms,
aryl radicals having preferably 6 to 8 carbon atoms, in which the alkyl radicals, cycloalkyl radicals or aryl radicals mentioned above may each be substituted by 1.2 or 3 hydroxyl groups; guanidine compounds such as cyanoguanidine, N-cyano-N-
Methyl-guanidine, N-cyano-N'-ethylguanidine, N-cyano-N'-isopropylguanidine, N
-Cyano-Nl-tert-butylguanidine, N-cyano+ N/-dodecylguanidine, N-cyano-Hl-
Cyclohexylguanidine, N-cyano-N/-benzylguanidine, N-cyano-N'-phenylguanidine, 1(-cyano-19'-hydroxymethylguanidine, N-cyano-N'-(2-hydroxyethyl) -guanidine or N-N'-dicyanoguanidine.

Stabilizing aids are optionally used in amounts of 0.01 to 1% by weight, preferably 0.1 to 0.5% by weight, based on the polyoxymethylene.

Furthermore, the molding compositions can also contain known light stabilizers such as benzophenone, acetophenone or triazine derivatives.

Similarly, other customary additives such as dyes, pigments, reinforcing agents and fillers are also added.

The stabilizer is incorporated into the polyoxymethylene as a powder in a commercially available mixer, such as a dry mixer, or dissolved in a suitable solvent, such as methanol, acetone or methylene chloride, and added to the polymer under stirring. The solvent is then allowed to evaporate again.

The polyoxymethylenes stabilized according to the invention are homopolymers of formaldehyde or cyclic oligomers of formaldehyde, such as trioxane, whose hydroxyl end groups are chemically protected, for example by esterification or etherification, and of formaldehyde or Cyclic oligomers of formaldehyde, preferably trioxane, are copolymers having oxyalkylene groups having at least 2, preferably 2 to 4 adjacent carbon atoms in the main atom side chains. The proportion of comonomers in the copolymer is from 0.1 to 50% by weight, preferably from 0.1 to 15% by weight.

As compounds suitable for copolymerization with cyclic oligomers of formaldehyde or formaldehyde, preferably trioxane, use is made in particular of cyclic ethers and/or cyclic acetals and/or string polyacetals. In particular, cyclic ethers with 3 to 5 negative rings, preferably epoxides, and also cyclic acetals with 5 to 11 members, preferably 5 to 8 members, especially those whose carbon chain is interrupted by an oxygen atom at a distance of 2 carbon atoms. Suitable are cyclic formals of α,ω-diols having 2 to 8, preferably 2 to 4 carbon atoms in the chain, which may be separated, as well as string-like polyformals.

Particularly suitable are compounds of the formula: where R is a hydrogen atom, 1 to 3 halogen atoms, preferably 1 to 6 optionally substituted with chlorine atoms, preferably means an alkyl group having 1 to 3 carbon atoms, an alkoxymethyl group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, a phenyl group or a phenoxymethyl group; represents an integer, where y is equal to zero, and y represents an integer from 1 to 3, where xJd is equal to zero or zf-J.

2, and 2 represents 3 to 6, preferably 3 or 4, with X equal to zero and y equal to 1.

As cyclic ethers used are, for example, ethylene oxide and epichlorohydrin as well as propylene oxide, styrene oxide, cyclohexene oxide, oxycyclobutane, phenyl glycidyl ether and butanediol glycidyl ether, while as cyclic polymers there are used, for example, 1,3-dioxocune, 1. 5-Dioxocune and 1,5,6-) dioxocanna and 4-chloromethyl-1,3-dioxolane, 1,3-dioxocune and 1,3-dioxasicbutene-(
5) is used.

The polyoxymethylene used according to the invention is a polymer, with 0.5 polymers of polymer in γ-butyrolactone containing 2% by weight of diphenylamine as a stabilizer.
The value of its reduced specific viscosity (RBV), measured at 140υ on a % solution, is between 0.6 and 3°0, preferably between 0.5 and 2 dlJ/y. The crystalline melting point of the polyoxymethylene is within the range of 150 to 180 μm.

The molding compositions according to the invention are processed by all the methods used for thermoplastics, such as injection molding, extrusion, blow molding, melt spinning or deep drawing.

They can be shaped bodies, such as strips, rods, bristles, fibers, plates,
Suitable for the production of semi-finished or finished products such as films, foils, tubes or hoses, as well as household items such as dishes or pots, and machine elements such as casings or gears. The molding composition according to the invention is particularly suitable for the production of injection molded articles having vents, corrugations or holes which prevent the flow of the molten composition within the mold.

Examples 1 to 12 and Comparative Examples A to C Acetylated formaldehyde homopolymer (RBV
-value: 0.90 J/f) f, tetrakis-[β
1.0% by weight of -(5,5-ditert-butyl-4-hydroxyphenyl)-propionyl-oxymethyl]-methane and 0°2 of the magnesium salt of the acid listed in Table 1.
Mix intimately with a weigher and granulate in a commercial extruder. The weight loss of the sample after heating for 45 to 420 minutes in 230 mm of air is determined for the dried granules. Further, before and after heating in a closed mold for 60 minutes at 230 mm, the granules were prepared to have a diameter of 4°5CrR1 and a thickness of 2.5 mm.
m circular molded plates were prepared, and then the yellowing of these plates was measured using a differential photometer (Manufacturing, Engineering).
G and EquipmentC! orp, (Ha
Measurement (yellowing value) with a Colomaster (Colomaster device) manufactured by Tboro, Pa., USA).

The granules are then injection molded into streamlined plates using a commercially available injection molding machine (material temperature: 200 υ; tool temperature: 80 t'; injection pressure and afterpressure = 45 bar; piston running speed: medium). This plate is particularly suitable for checking stripes that may occur during the injection process. Tetrakis-[β-(3,
Polyoxymethylene according to the invention, stabilized with a mixture of 1.0 Mfl 5-ditert-butyl-4-hydroxyphenyl)-propionyl-oxymethyl]-methane and 0.2 Mfl 1% of the magnesium salt of malic acid. The molded articles produced from the molding compositions do not exhibit any striations (see FIG. 1), while the tetrakis-[β-(3,5-
Di-tert-butyl-4-hydroxyphenyl)-propionyl-oxymethyl]-methane 1. Molded articles made from a similar molding composition stabilized with a mixture of -3% ofR and 0.2% calcium stearate show clearly visible striations (Fig. 2). reference).

The results of the test are clear from Table 1.

Table 1 Example 13 and Specification D Copolymer (R(iV-value: 0.82
eLll/W) with 0.5% by weight of 1,6-bis-[β-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionyloxy]-hexane and 0.1% by weight of alkaline earth metal salt. and granulate in a commercially available extruder. 23'Oi in air for dried granules;
The weight loss of the sample after heating for 120 minutes is measured.

Additionally, the yellowing values were measured before and after heating for 60 minutes under the same conditions as Examples 1 to 12.

Furthermore, valve plates are injection molded from the granules under the conditions described in Examples 1 to 12, and the surface condition thereof is inspected. The valve plate manufactured from the molding composition according to the invention shows a smooth and impeccable surface (see Figure 3), whereas the valve plate according to the comparative example has fine particles near the holes. It exhibited cracks, which made the valve plate unfit for use (No. 4)
(see figure).

Table 2 Example 14 A copolymer obtained from 98% by weight of Triochair and 2% by weight of ethylene oxide (R8V value: 0.82 d1/liter) was mixed with 1,6-bis-[β-(3,5 -di-tert-butyl-4
-hydroxyphenyl)-flopionyloxy]-hexane, 0.1% by weight of calcium lactate and 0.02% by weight of cyanoguanidine and granulated in a commercial extruder. For the dried granules, the weight loss of the sample after heating to 260 υ in air for 120 minutes is determined and a measurement of 111t of 2.2% is obtained. Furthermore, Example 1~
The yellowing values were measured before and after heating for 50 minutes in accordance with No. 12 and were 0.6 to 12.4.

Molded articles made from these O granules exhibit a smooth, striation-free surface.

The gist of the invention is the description of the claims, but the embodiments thereof include the following matters.

(1) Trioxane and cyclic ether and/-! as polyoxymethylene! , or a copolymer consisting of a cyclic acetal and/or a linear polyacecule.

(2) A molding composition according to the claims, characterized in that the polyoxymethylene is a copolymer consisting of trioxane and a three-membered cyclic ether.

(5) Hexanediol-(1,6
), trimethylolethane or pentaerythritol and β-(3,5-ditert-butyl-4-hydroxyphenyl)-propionic acid.

(4) A molding composition according to the claims, characterized in that component (b) is a calcium or magnesium salt of a saturated, unsaturated aliphatic carboxylic acid having 2 to 9 carbon atoms.

(5) A molding composition according to the claims, characterized in that component (b) is calcium lactate or magnesium lactate.

(6) A molding composition according to the claims, characterized in that component (C) is cyanoguanidine.

(7) The following formula (in the above formula, R1 is an alkyl group having 1 to 6 carbon atoms, R2 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and A is an alkyl group having 1 to 12 carbon atoms. a divalent to hexavalent aliphatic hydrocarbon group having the following formula, m means zero or an integer from 1A to 6, and corresponds to one number of n Jd A), and a compound represented by 2 to 9 alkaline earth metal salts of aliphatic di- or tricarboxylic acids having 7 to 9 carbon atoms or araliphatic or aromatic carboxylic acids having 7 to 9 carbon atoms; % (wherein R is a hydrogen atom, 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 1 to 12 carbon atoms) , in which the alkyl, cycloalkyl or aryl groups mentioned above may each be substituted by 1, 2 or 3 hydroxyl groups). A method for producing a molded article from a thermoplastic molding composition, characterized in that polyoxymethylene containing as an oxidation stabilizer is used as a molding composition.

[Brief explanation of drawings]

FIG. 1 is a photograph showing the surface condition of a molded article manufactured from a polyoxymethylene molding composition according to the invention;
FIG. 2 is a photograph of a molded article manufactured from a molding composition not according to the invention, FIG. 3 is a photograph of a molded article manufactured from a molding composition also according to the invention, and FIG. 4 is a photograph of a molded article manufactured from a molding composition also according to the invention. is a photograph of a molded product according to a comparative example. Agent Hikaru Esaki Good Agent Mitsushi Ezaki Continuation of page 1 ■Int, C1,' Identification symbol Issued by the Office's internal management control [phase]
Inventor: Luhrheinz Pull (German Federation) Inventor: Günther Sächst (German Federation)
0 Tsukel, 43 countries, Langenhain/Taunus, Am Dort, 5

Claims (1)

[Scope of Claims] (a) A compound of the following formula (in the above formula, R4 is an alkyl group having 1 to 6 carbon atoms, and R2 is a hydrogen atom) in an amount of 0.05 to 4M based on polyoxymethylene. or an alkyl group having 1 to 6 carbon atoms, A is a divalent to hexavalent aliphatic hydrocarbon group having 1 to 12 carbon atoms, m is zero or an integer of ) to 6, and (n corresponds to the valence of A), and (b) 0.01 to 3% R% based on polyoxymethylene,
A stabilized polyoxymethylene molding composition containing an alkaline earth metal salt of a carboxylic acid, wherein the alkaline earth metal salt of a carboxylic acid is a fat having 2 to 9 i;A'r atoms. Family no,
containing an alkaline earth metal salt of di- or tricarboxylic acid or an araliphatic or aromatic carboxylic acid having 7 to 9 carbon atoms, and optionally (C)
0.0 + to 1% by weight, based on polyoxymethylene, of the following formula % (wherein R is a hydrogen atom, an ano group, an alkyl group having 1 to 12 carbon atoms, 6 to 12% by weight) a cycloalkyl group having 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, in which case each of the abovementioned alkyl, cycloalkyl or aryl groups contains 1.2 or 6 carbon atoms. The above-mentioned anodized polyoxymethylene molding composition, characterized in that it contains a metal compound represented by (optionally substituted with a hydroxyl group).