JPH07207118A - Polyoxymethylene composition - Google Patents

Abstract

PURPOSE:To obtain a polyoxymethylene composition without emitting the smell of formaldehyde and fouling a metallic mold in molding by blending a polyoxymethylene with a sterically hindered phenolic antioxidant and a specific polyamine reactional product in a specified proportion. CONSTITUTION:This composition is obtained by blending polyoxymethylene with a sterically hindered phenolic antioxidant {preferably pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], etc.} in an amount of 0.01-5wt.%, preferably 0.1-3wt.% based on the polyoxymethylene and a polyamine reactional product prepared by reacting a polyamine having >=2 primary and/or secondary amino groups (preferably ethylenediamine, etc.) with a cyanuric chloride and further reacting the resultant product with ammonia (derivative) in an amount of 0.01-10wt.%, preferably 0.1-2wt.% based on the polyoxymethylene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyoxymethylene composition which produces less formaldehyde odor during molding and has improved mold deposits.

[0002]

BACKGROUND OF THE INVENTION Polyoxymethylene resins are polymerized or copolymerized from formaldehyde or its cyclic oligomer trioxane, or a comonomer such as trioxane and a cyclic ether or cyclic formal to stabilize the terminal. It is treated with chemicals and antioxidants and other heat stabilizers are added to prevent decomposition. The antioxidant added to the polyoxymethylene resin is a sterically hindered phenol compound or a sterically hindered amine compound, and other heat stabilizers include polyamides, urea derivatives, amidine compounds, alkali or alkaline earth metal compounds. Compounds such as hydroxides, organic or inorganic acid salts have been proposed, but polyoxymethylene compositions containing these compounds are subjected to the action of heat and oxygen in the cylinder of the molding machine during molding, Formaldehyde odor is liable to be generated and the working (hygiene) environment is deteriorated, or if molding is performed for a long time, fine powdery substances and tar-like substances (MD) adhere to the mold surface and the appearance of molded products deteriorates. Although it has drawbacks in the molding process such as causing the above, and various ideas and proposals have been made so far, satisfactory results have not always been obtained.

[0003]

Means for Solving the Problems The present inventors have conducted a detailed study on stabilizers, and as a result, by blending a specific polyamine reactant with an antioxidant, the intended purpose can be achieved. The present invention has been completed and the present invention has been completed. That is, the present invention is based on polyoxymethylene,
Sterically hindered phenolic antioxidant 0.01 to 5% by weight,
Polyamine reaction product obtained by further reacting a reaction product of polyamine having two or more primary and / or secondary amino groups with cyanuric chloride with ammonia or a derivative thereof 0.01
To 10% by weight of the polyoxymethylene composition.

The constituent components of the composition of the present invention will be described in detail below. The polyamine reaction product used in the present invention is obtained by further reacting a reaction product of a polyamine having two or more primary and / or secondary amino groups with cyanuric chloride with ammonia or a derivative thereof. As the polyamine used here, ethylenediamine,
Diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, propylenediamine, dipropylenetriamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, cyclohexylaminopropylamine,
Aminoethylethanolamine, monohydroxyethyldiethylenetriamine, bishydroxyethyldiethylenetriamine, N- (2-hydroxypropyl) ethylenediamine, piperazine, 1-aminoethylpiperazine, 1,3-di- (4-piperidyl) propane, polyallylamine, polyethylene Aliphatic amines such as imines, phenylenediamine, tolylenediamine, xylylenediamine, tolidine, 4,4'-diaminodiphenylmethane, 3,
3'-dimethyl-4,4'-diaminodiphenylmethane, dianisidine, 4,4'-diaminobenzanilide, diaminophenyl ether, 1,5-diaminonaphthalene, 2,4,6-
Aromatic amines such as triaminopyridine, dicyandiamide, melamine, amidine compounds such as 2,5-diamino-1,3,4-triazole, guanamine compounds such as acetoguanamine, benzoguanamine, acryloguanamine, polyacryloguanamine, urea or urea Examples include urea derivatives such as ethylene urea. In the present invention, any of these polyamines can be used, but aliphatic polyamines or aromatic polyamines having at least one or more primary amino groups are preferred, and ethylenediamine, diethylenetriamine, triethylenetetramine, tetramethylenediamine, hexa Methylenediamine and xylylenediamine are particularly preferred substances. These polyamines may be used alone or in combination of two or more.
Examples of ammonia or its derivative used here include ammonia, ammonium hydroxide, ammonium carbonate, ammonium phosphate, and ammonium borate.

The polyamine compound used in the present invention is produced by a known method. That is, first, cyanuric chloride is added to a polar solvent having no active hydrogen such as chloroform, dioxane, dimethylacetamide, or dimethylsulfoxide in an amount of equimolar or less with respect to the amino group and / or imino group of the polyamine. The reaction temperature and time vary depending on the type of polyamine and the solvent, but are 20 to 120 ° C and 30 minutes to 3 minutes.
The reaction solution may be sufficiently stirred for a time. Although the three chlorine groups of cyanuric chloride are equivalent, the rate at which the second and third chlorine react is slower than the rate at which the first chlorine reacts. The reaction of the polyamine reactant in which one chlorine group in cyanuric chloride reacts with the active hydrogen of the amino group and / or imino group of the polyamine can be obtained by the operation of the first step. Next, by passing a large excess of ammonia into the same reactor, the unreacted chlorine group of cyanuric chloride bound to polyamine is replaced with an amino group. The crude polyamine reactant can be obtained by evaporating the reaction solution or by pouring the reactant into ion-exchanged water to precipitate the reactant. Furthermore, after washing this crude polyamine reaction product several times with an aqueous sodium sodium hydroxide solution and ion-exchanged water, 40-
The purified polyamine reactant can be obtained by washing at 120 ° C. or acetone and drying at room temperature. Such a polyamine reactant is blended in combination with an antioxidant to suppress the decomposition of polyoxymethylene, and
Since it shows the effect of decomposing and trapping the generated formaldehyde, the generation of decomposition gas at the time of molding is suppressed as much as possible, and since it itself has almost no sublimation or decomposability, it hardly generates mold deposits. Guessed.

Next, sterically hindered phenolic antioxidants used in the present invention include 2,2'-methylenebis (4methyl-6-t-butylphenol) and 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-
Hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-]
Hydroxyphenyl) propionate], triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,3,
5-Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy-benzyl) benzene, n-octadecyl-3- (4'-hydroxy-3 ', 5'-di- t-butylphenol) propionate, 4,4'-methylenebis (2,6
-Di-t-butylphenol), 4,4'-butylidene-bis- (6-t-butyl-3-methyl-phenol), 2,2 '
-Thiodiethyl-bis- [3- (3,5-di-t-butyl-
4-hydroxyphenyl) propionate], di-stearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, 2-t-butyl-6- (3-t-butyl-5-methyl-2-hydroxy) Benzyl) -4-methylphenyl acrylate, N, N′-hexamethylenebis
(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,9-bis {2- [3- (3-t-butyl-
4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxasparo [5,5] undecane and the like, and at least one or more of these Can be used. Among these, pentaerythritol tetrakis [3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis- [3- (3-
t-butyl-5-methyl-4-hydroxyphenyl) propionate], 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1 -Dimethylethyl} -2,4,8,10-tetraoxasparo [5,5] undecane is a particularly preferred substance.

The amount of the sterically hindered phenolic antioxidant added and blended in the present invention is 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on polyoxymethylene. If the amount added is too small, no sufficient effect can be obtained, and if the amount added is too large, the effect of thermal stability reaches saturation, rather causing discoloration, which is not preferable. The amount of the polyamine reactant added and blended in the present invention is 0.01 to 10% by weight, preferably 0.1 to 3% by weight, based on polyoxymethylene. If the amount added is too small, no sufficient effect can be obtained, and if the amount added is too large, the mechanical properties of the material tend to be impaired, which is not preferable.

The polyoxymethylene to which the above-mentioned additives are added is a polymer compound having an oxymethylene group (--CH ₂ O--) as a main constituent unit, and other than polyoxymethylene homopolymer and oxymethylene group. It may be any of copolymers, terpolymers and block copolymers containing a small amount of other constitutional units, and the molecule may have not only a linear structure but also a branched or crosslinked structure. Further, there is no particular limitation on the degree of polymerization or the like.

The composition of the present invention is not essential, but depending on the purpose, a nitrogen-containing compound other than the polyamine reactant of the present application, an oxide of an alkali or alkaline earth metal, a hydroxide, an inorganic acid salt, It is also possible to use one or more metal-containing compounds such as carboxylates or alkoxides in combination.
In order to further impart desired properties to the composition of the present invention depending on its purpose, conventionally known additives such as lubricants, nucleating agents,
It is also possible to add one or more kinds of release agents, antistatic agents and other surfactants, or organic polymer materials, inorganic or organic fibrous, powdery or plate-like fillers. .

The method for preparing the composition of the present invention is not particularly limited, and it can be easily prepared by the known equipment and method generally used as a conventional method for preparing a resin composition. For example,
i) After mixing each component, kneading and extruding with an extruder to prepare pellets, and then molding, ii) once preparing pellets with different compositions, mixing the pellets in a prescribed amount and molding A method for later obtaining a molded article having a target composition, ii
i) A method of directly charging one or more of each component into a molding machine,
Either can be used. In addition, mixing a part of the resin component in the form of fine powder with the other components and adding the powder is a preferable method for uniformly blending these components. Further, the resin composition according to the present invention, extrusion molding, injection molding,
It can be formed by any of compression molding, vacuum molding, blow molding, and foam molding.

[0011]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. still,
The evaluation method shown in the following examples is as follows. 1) Moldability The sample polyoxymethylene composition was continuously molded (about 24 hours) using an injection molding machine under constant conditions, and the following evaluations were performed. Formaldehyde odor during molding Twenty molded products (approximately 30 mm x 5 mm x 1.5 mm) immediately after molding are placed in a polyethylene bag with a zipper (dimensions: 10 cm x 14 cm) and sealed. After a certain period of time, open the package and remove the odor
The grade was evaluated. A: No irritating odor B: Formaldehyde odor felt very slightly C: Formaldehyde odor slightly high D: Amount of formaldehyde odor Amount of mold deposits When performing continuous molding, the stains on the mold can be visually observed in five stages. evaluated. A ... None B ... Extremely C ... Low D ... Slightly high E ... High 2) Weight loss rate upon heating The weight loss rate when 5 g of the sample was heated in air at 235 ° C. for 45 minutes is shown.

Examples 1 to 7 Polyoxymethylene copolymer (manufactured by Polyplastics Co., Ltd., DURACON) containing the hindered phenolic antioxidant and the polyamine reactant shown in Table 1 in the proportions shown in Table 1. The mixture was added and mixed with to obtain a pelletized composition with an extruder. Then, this pellet was used for the above evaluation.
The results are shown in Table 1. Comparative Examples 1 to 4 In the same manner as described in Examples 1 to 7,
In place of the polyamine reaction product shown in No. 7, 0.3% by weight of the substances shown in Table 1 was added to obtain pellets. The evaluation results of the composition are shown in Table 1 together with the examples.

[0013]

[Table 1]

Note-1) Sterically hindered phenolic antioxidant a) Triethylene glycol-bis- [3- (3-t-
Butyl-5-methyl-4-hydroxyphenyl) propionate] b) Pentaerythritol tetrakis [3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate] Note-2) Polyamine reaction product c) Polyamine reaction product 1 Four-necked flask (500 ml) containing 200 ml of chloroform.
50 g of cyanuric chloride was added to and stirred. After the cyanuric chloride is completely dissolved in chloroform, ethylenediamine 9ml
Was gradually added with a dropping funnel. The temperature of the reaction solution was controlled at 25 ± 3 ° C. by cooling the flask with a low temperature water bath so that the temperature of the system would not rise too much due to the heat of reaction.
The reaction solution was continuously stirred even after the addition of a predetermined amount of ethylenediamine, and after 30 minutes, ammonia was bubbled through the reaction solution at a flow rate of 1 liter / hr for 30 minutes. Then, the solvent of the reaction solution was evaporated by a rotary evaporator to obtain a crude polyamine reaction product. This was neutralized and washed by stirring in 200 ml of a 1N aqueous sodium hydroxide solution, filtered, and then washed and filtered with 100 ml of ion-exchanged water three times. This is further washed and filtered with acetone,
After drying at room temperature, a fine powder of purified polyamine reaction product 1 was obtained by rubbing in a mortar. d) Polyamine reactant 2 Triethylenetetramine 10 instead of ethylenediamine
A sample was prepared under the same conditions as the polyamine reaction product 1 except that ml was used to obtain a fine powder of the purified polyamine reaction product 2. e) Polyamine reactant 3 1,4-dioxane instead of chloroform and m-xylylenediamine 17.4 ml instead of ethylenediamine
The reaction was terminated under the same conditions as for the polyamine reaction product 1 except that the temperature of the reaction solution was controlled to 50 ± 3 ° C. using a hot water bath. The reaction solution was poured into 1 liter of 1N aqueous sodium hydroxide solution to precipitate the reaction product, which was then filtered to obtain a crude polyamine reaction product. Thereafter, washing and filtration with ion-exchanged water were repeated 3 times to obtain fine powder of purified polyamine reaction product 3 in the same manner as for polyamine reaction product 1.

[0015]

As is clear from the above description and the examples, the present invention significantly improves the thermal stability of polyoxymethylene, has less stain on the mold even during continuous molding for a long time, and Generation of formaldehyde odor during molding is remarkably suppressed, and it is possible to obtain a resin composition that is very preferable in terms of occupational hygiene.

Claims (3)

[Claims] 1. A reaction product of 0.01 to 5% by weight of a sterically hindered phenolic antioxidant based on polyoxymethylene, a polyamine having two or more primary and / or secondary amino groups, and cyanuric chloride. Polyamine reactant obtained by reacting ammonia or a derivative thereof 0.01 to 10
A polyoxymethylene composition containing 100% by weight. 2. The polyoxymethylene composition according to claim 1, wherein the polyamine as a raw material of the polyamine reactant is an aliphatic polyamine or an aromatic polyamine having at least one or more primary amino groups. 3. The polyoxymethylene composition according to claim 2, wherein the polyamine as a raw material of the polyamine reactant is selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetramethylenediamine, hexamethylenediamine and xylylenediamine. object.