CA2136010A1 - Polyoxymethylene composition and molded article thereof - Google Patents
Polyoxymethylene composition and molded article thereofInfo
- Publication number
- CA2136010A1 CA2136010A1 CA 2136010 CA2136010A CA2136010A1 CA 2136010 A1 CA2136010 A1 CA 2136010A1 CA 2136010 CA2136010 CA 2136010 CA 2136010 A CA2136010 A CA 2136010A CA 2136010 A1 CA2136010 A1 CA 2136010A1
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- CA
- Canada
- Prior art keywords
- polyoxymethylene
- parts
- weight
- group
- article
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L59/00—Compositions of polyacetals; Compositions of derivatives of polyacetals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K13/00—Use of mixtures of ingredients not covered by one single of the preceding main groups, each of these compounds being essential
- C08K13/02—Organic and inorganic ingredients
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
To provide a polyoxymethylene composition which is improved in heat stability, particularly the generation of mold deposits during molding and malfunction due to the formic acid generated from the composition (for example, stain with the substance bleeding from a part made from a rubber and corrosion of a magnetic metal member). To 100 parts by weight of a polyoxymethylene, (a) 0.01 to 5.0 parts by weight of an antioxidant. (b) 0.01 to 5.0 parts by weight of a specific amine polymer and (c) 0.001 to 10 parts by weight of at least one metal-containing compound selected from among oxides and carbonates of magnesium and calcium are added.
Description
2 1 3 6 0 1 0 ~ ?
. ~;
Specification POLYOXYMETHYLENE COMPOSITION AND MOLDED
ARTICLE THEREOF
[Field of Industrial Application]
The present invention relates to a polyoxy-methylene composition which is improved in heat stability, particularly reduced in the amount of mold deposit formed during molding, and which little causes malfunction due to the formic acid generated from the composition (e.g., contamination with bloom from a .
. :. .:
rubber part or corrosion of a magnetic metal member), ~ --and a molded article thereof.
:
[Prior Art]
Polyoxymethylene is a homopolymer of formaldehyde or trioxane which is a cyclic oli.gomer of ~ormaldehyde or a copolymer o~ trioxane with a cycl:Lc ether or a cyclic formal which is prevented from undergoing decomposition by the stabilization of the molecular ends and the addition of an antioxidant and other heat stabilizer.
Sterically hindered phenols and sterically hindered amines have been proposed as the antioxidant to be added to polyoxymethylene, while polyamide, urea derivatives, amidine compounds and hydroxides of alkali and alkaline earth metals as the heat ::
:
~: - 1 -; ~
., ,, ~-- 21360~0 stabilizer. When, however, a polyoxymethylene resin composition containing such an antioxidant or stabilizer is exposed to heat and oxygen in the cylinder of a molding machine, it is liable to emit a formaldehydic odor, which deteriorates the working atmosphere. Further, when the molding of the composition is continued for a long time, a powdery or tarry substance, i.e., mold deposit (MD) adheres to the mold surface to give a molded article poor in surface appearance. Thus, the composition is still problematic in processability and moldability.
Although many contrivances and proposals have been made to solve the problems, the effects are not always satisfactory.
The inventors o~ the present inverltlon have already proposed a polyoxymethylene compositlon remarkably improved in heat stability as disclosed in Japanese Patent Laid-Open No. 200857/1991 for the purpose of overcoming the disadvantages of the polyoxymethylene composition of the prior art.
Although the composition proposed in the Japanese , Patent Laid-open No. 200857/1991 is improved in heat stability, it has been required to be further improved in the properties as the material depending upon the application field thereof.
1~ .' :::
` 21~6010 One of such requirements is an improvement in the prevention of an electromechanical component of electrical or electronlc equipment such as an audio or video apparatus from malfunction.
More precisely, even the electromechanical --component of an audio or video apparatus produced and assembled in a highly cleaned environment (e.g., in a dust-free room) for the purpose of preventing the same from being contaminated with environmental factors frequently suffers from operational troubles in practical use when it ~s exposed to a high-temperature and high-humidity atmosphere, though it is not contaminated with dust or other environmental ~actors.
This is because the additives contained in a rubber roller constituting the electromechanical component of an audio or video apparatus bleed to the surface oE
the roller tc) contaminate the magnetic head through a magnetic tape. As a temporary countermeasure against such malfunction, it has been a practice to clean the rubber surface of the electromechanical component of an audio or video apparatus exposed to a high~
temperature and high-humidity atmosphere. However, this countermeasure is not only a nonpermanent one but also requires a great deal of labor, though it is -~
effectiYe to some extent. Further, a magnetic metal ;
. ~;
Specification POLYOXYMETHYLENE COMPOSITION AND MOLDED
ARTICLE THEREOF
[Field of Industrial Application]
The present invention relates to a polyoxy-methylene composition which is improved in heat stability, particularly reduced in the amount of mold deposit formed during molding, and which little causes malfunction due to the formic acid generated from the composition (e.g., contamination with bloom from a .
. :. .:
rubber part or corrosion of a magnetic metal member), ~ --and a molded article thereof.
:
[Prior Art]
Polyoxymethylene is a homopolymer of formaldehyde or trioxane which is a cyclic oli.gomer of ~ormaldehyde or a copolymer o~ trioxane with a cycl:Lc ether or a cyclic formal which is prevented from undergoing decomposition by the stabilization of the molecular ends and the addition of an antioxidant and other heat stabilizer.
Sterically hindered phenols and sterically hindered amines have been proposed as the antioxidant to be added to polyoxymethylene, while polyamide, urea derivatives, amidine compounds and hydroxides of alkali and alkaline earth metals as the heat ::
:
~: - 1 -; ~
., ,, ~-- 21360~0 stabilizer. When, however, a polyoxymethylene resin composition containing such an antioxidant or stabilizer is exposed to heat and oxygen in the cylinder of a molding machine, it is liable to emit a formaldehydic odor, which deteriorates the working atmosphere. Further, when the molding of the composition is continued for a long time, a powdery or tarry substance, i.e., mold deposit (MD) adheres to the mold surface to give a molded article poor in surface appearance. Thus, the composition is still problematic in processability and moldability.
Although many contrivances and proposals have been made to solve the problems, the effects are not always satisfactory.
The inventors o~ the present inverltlon have already proposed a polyoxymethylene compositlon remarkably improved in heat stability as disclosed in Japanese Patent Laid-Open No. 200857/1991 for the purpose of overcoming the disadvantages of the polyoxymethylene composition of the prior art.
Although the composition proposed in the Japanese , Patent Laid-open No. 200857/1991 is improved in heat stability, it has been required to be further improved in the properties as the material depending upon the application field thereof.
1~ .' :::
` 21~6010 One of such requirements is an improvement in the prevention of an electromechanical component of electrical or electronlc equipment such as an audio or video apparatus from malfunction.
More precisely, even the electromechanical --component of an audio or video apparatus produced and assembled in a highly cleaned environment (e.g., in a dust-free room) for the purpose of preventing the same from being contaminated with environmental factors frequently suffers from operational troubles in practical use when it ~s exposed to a high-temperature and high-humidity atmosphere, though it is not contaminated with dust or other environmental ~actors.
This is because the additives contained in a rubber roller constituting the electromechanical component of an audio or video apparatus bleed to the surface oE
the roller tc) contaminate the magnetic head through a magnetic tape. As a temporary countermeasure against such malfunction, it has been a practice to clean the rubber surface of the electromechanical component of an audio or video apparatus exposed to a high~
temperature and high-humidity atmosphere. However, this countermeasure is not only a nonpermanent one but also requires a great deal of labor, though it is -~
effectiYe to some extent. Further, a magnetic metal ;
. 2l3~la article such as a magneto-optical disk or metallized tape often corrodes, when used together with a molded polyoxymethylene article in a relatively hermetically sealed state. Under these circumstances the fundamental solution of these problems has been expected.
[Disclosure of the Invention]
In order to solve the above problems, the inventors of the present invention have made detailed studies on the blooming of the rubber part and the corrosion of the magnetic metal article to -find that the material of the electromechanical component of an audio or video apparatus relates closely to the problems. More precisely, it has been -found that the molded polyoxymethylene article used mainly as an electromectlanical component of' an audio or video apparatus, such as a chassis (base plate), gear or bearing, a part of a tape cassette, such as a reel or guide roll, or a part of a disk cartridge, such as a shutter or cartridge body causes the blooming of a rubber part such as a roller or belt or the corrosion of a magnetic metal article under relatively high-temperature and high-humidity conditions. Further, studies have been made on the reason for this ~t . problematic phenomenon to find that the formic acid ,1 .
,~J " .
213~010 contained in the molded polyoxymethylene article is ~
released through the medium of water contained in a high-humidity atmosphere to adhere to the rubber part and the magnetic metal article and penetrate into them, and that the formic acid penetrating into the rubber part reacts with the difficultly water-soluble magnesium oxide contained in the rubber to form easily water-soluble magnesium formate, which bleeds to the surface of the rubber part to contaminate the magnetic head through a tape, while the formic acid penetrating into the magnetic metal article corrodes the metal.
Although polyoxymethylene is improved in heat ~ ~
stability by the addition o~ an antioxidant and ::
various stabilizers as described above, it cannot ~:
avoid being thermally decomposed a little in processing and molding, so that the molded article thereof conta:Lns formaldehyde and formic acid which are the products of decomposition. The formaldehyde is released around as a gas when the molded article is heated to tens of degrees centigrade or above, so that ~;
the amount of formaldehyde remaining in the molded ~ :
article can be reduced remarkably by subjecting the article to high-temperature treatment or vacuum degassing, while the amount of the formic acid conteined in the article can little be reduced even by ,~ .
2~L36010 treating it at a temperature of as high as one hundred and tens of degrees centigrade or in hot water.
The inventors of the present invention have further made studies to overcome this disadvantage, and have found that the amount of the formic acid generated from a molded polyoxymethylene article can be remarkably reduced by the addition of an antioxidant, a specific amine polymer and a specific metallic compound. The present invention has been accomplished on the basis of this finding.
Thus, the present invention relates to a po]yoxymethylene composition prepared by blending 100 parts by weight of polyoxymethylene with (a) 0.01 to 5.0 parts by weight of an antioxidant, (b) 0.01 to 5.0 parts by weight of an amine polymer havlng amino groups on its side chains as represented by the general formula (I) and (c) 0.001 to 10 parts by weight of at least one metal-containing compound selected from among oxides and carbonates of magnesium and calcium, and a molded polyoxymethylene article produced by molding the composition, characteri~ed in that the amount of the formic acid generated from the molded article of the polyoxymethylene composition is ,~ 1.0 ~g or below per square centimeter of the surface area of the molded article.
,,!
.... . .
,. . .
. .~ . , : : -. :,.,,i. . : : .::
,."~, . : : , . - :-:; :
,: i: . .
.. :
2~31~0~0 H R
_ C-C - - tl) H X
N~2 [wherein R represents a hydrogen atom, an alkyl group, a phenyl group, an alkyl-substituted phenyl group or 1~2 X-; and X represents an alkylene group, a carbonyl group, a carboxyalkylene group, an alkyleneoxy-carbonylalkyl group, a phenylene group, an alkyl-substituted phenylene group, an amido group or an alkyleneamido group or nil.]
The present invention will now be described in detail.
The polyoxymethylene to be used in the present invention is a polymer mainly composed of oxymethylene (-CH20-) units, which may be either a polyoxymethylene homopolymer or a copolymer, terpolymer or block copolymer containing small amounts of other constituent units )n addition to the oxymethylene units. Further, these (co)polymers may be linear, -~
branched or crosslinked. Furthermore, the degree of polymerization thereo~ is not particularly limited.
The antioxidant (a) to be used in the present `!
~ - 7 -invention includes hindered phenols such as 2,2'-methylenebis(4-methyl-6-t-butylphenol), 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetrakis[3-(3,5-di-t-buty1-4-hydroxyphenyl)propionate~, triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], ~ :
1,3,5-trimethyl-2,2,6--tris(3,5-di-t-butyl-4-hydroxy-benzyl)benzene, n-octadecyl 3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-butylidenebis(6-t-butyl-3-methyl-phenol), distearyl 3,5-di-t-butyl-4-hydroxybenzyl-phosphonate, 2-t-butyl-6-(3-t-butyl-5-methyl-2-hydioxybenzyl-4-methylphenyl acrylate and N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydro-cin~amamlde; and phosphorus antioxidants such as triphenyl phosphite, trisnonylphenyl phosphite, tris(Z,4-di-t-butylphenyl) phosphite, tris(2-t-buty1-4-methylphenyl) phosphite, tris(Z,4-di-t-amylphenyl) phosphite, , tris(2-t-butylphenyl) phosphite, tris(2-t-phenylphenyl) phosphite, tris(2-(1,1-dimethylpropyl)-phenyl) phosphite, tris(2,4-(1,1-dimethylpropyl)-. phenyl) phosphite, tris(2-cyclohexylphenyl) phosphite and tris(2-t-butyl-4-phenylphenyl) phosphite. In addition, hindered amine antioxidants can also be : - 8 -:,~
.`,`', . ', .',''~i' '' ' ''' ' ' ~ ' . . ~ ' : , .. . . .
'." "` ' ~ . : ' ' ''',, ' ' , ' : ' ' ~ "
used, and one or two or more of these may be used.
Among them, 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~ and N,N'-hexamethylenebis-(3,5-di-t-butyl-4-hydroxyhydrocinnamamide) are particularly preferable substances.
Although the amine polymer (b) to be used in the present invention may be any one comprising constituent units represented by the above general formula (1), it is preferably a homoplymer, corosslinked polymer or copolymer having a molecular weight of 1000 or above and composed of constituent , units derived from one or more monomers selected from i among allylamine, acrylamide, acrylohydrazide, methacrylohyclrazide, aminoalkyl acrylate, aminoalkyl :1 , methacrylate, vinylalkylamine and so forth, or a copolymer comprising one or more of the above amine monomers and one or more monomers selected from among : ethylene, propylene, butylene, butadiene, styrene, acrylonitrile, acrylic acid esters, methacrylic acid esters and so forth. These amine polymers may be used alone or as a mixture of two or more of them.
The molecular weight of the amine polymer to be '~
,~. _ g _ , used in the present invention is preferably 1000 or above, still preferably 10000 to 100000. When the molecular weight is too low, the resulting composition or molded article will suffer from the bleeding of the amine polymer and the obJective effect of the present invention will not be attained.
Among the above amine polymers, it is preferable ~-to use a homopolymer, crosslinked polymer or copolymer having a molecular weight of 1000 or above and comprising constituent units derived from allylamine or acrylamide.
According to the present invention, the amount of the antioxidant (a) to be added is 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight per 100 j parts by weight of the pol.yoxyrnethylene, whlle the amount of the amine polymer (b) is 0.01 to 5 parts by weight, preferably 0.01 to 1 part by weight per 100 parts by weight thereof. When the amounts of these components are too small, no sufficient effect will be attained, while when they are too large, no additional improvement in the heat stability will be attained, rather, the resulting composition will be liable to discolor unfavorably.
The metal-containing compound (c) to be used in the present invention is an oxide or carbonate of 'i - 10 - ' . !
!
:' :
~ ~ .
21360~0 magnesium or calcium, particularly, magnesium oxide, calcium oxide, magnesium carbonate or calcium carbonate.
The amount o~ these compound to be added i5 0 . 00 to 10 parts by weight, desirably 0.001 to 5 parts by weight, more desirably 0.001 to 2 parts by weight, most desirably 0.003 to 0.5 part by weight per 100 parts by weight of the polyoxymethylene. When the amount is less than 0.001 part by weight, the objective effect will little be attained, while when it exceeds 10 parts by weight, no additional reduction in the amount of the formic acid generated will be attained, rather, the resulting composition will be liable to discolor unfavorably.
The metal-contalning compound (c) and the antioxidant (a) may be aaded either to the monomer(s) ln the polymerization step or in the step of stabilizing t;he polymer.
It is pr-eferable that the polyoxymethylene composition of the present invention further contain a fatty acid ester having at least 10 carbon atoms, still preferably a fatty acid ester of a polyhydric alcohol -~or the purpose of minimizing the mold deposit formed during molding. Examples of such a compound ., '! include glycerol monopalmitate, glycerol monostearate, !
", '; - 11 -l :
~136010 glycerol monoisostearate, glycerol monobehenate and pentaerythritol tristearate. The amount of the ester to be added is 0.01 to 2.0 parts by weight, preferably 0.05 to 1.0 part by weight per 100 parts by weight of the polyoxymethylene.
The determination method of the amount of the formic acid generated will be described. It is effected by molding the above composition, cutting the moled article at need, measuring the surface area thereof, putting a proper amount (corresponding to a surface area of about 30 to 60 cm2) of the molded article in a hermetically sealed container (capacity:
100 ml) containing 1 ml of pure water in such a way that the molded article is not immersed in the water directly, allowing the molded article to stand as such at 60C for 168C, diluting the resulting aqueous solution in the hermetically sealed container to 100 ml, analyzing this solution for formic acid concentration (~g) by ion chromatograph (IC500 mfd. by Yokogawa-Hewlett-Packard, Ltd., column for organic acid, 0.1 mM aqueous solution of perchloric acid as the carrier), and calculating the amount of the formic acid generated per unit surface area of the molded article (~g/cm2).
The preferable molded polyoxymethylene article 'i, "' l - 12 --- 213~0~0 according to the present invention is one generating formic acid in an amount of at most 1.0 ~g per square centimeter of the surface area thereof, particularly preferably one generating formic acid in an amount of at most 1.0 ~g per square centimeter of the surface area and in an amount of at most 5.0 ~g per g of the resin component. The numerical regulation on the amount of the formic acid generated according to the present invention can be applied to not only articles molded from polyoxymethylene compositions containing conventional additives such as ordinary stabilizers and/or mold release agent, but also ones molded from polyoxymethylene compositions containing inorganic fillers and/or other polymers, as far as polyoxy-methylene occupies most of the surface thereof.
The polyoxymethylene composltion o~ the present invention may further contain one or more members selected frorrl among nitrogen-containing compounds other than the amine polymers (b) according to the present invention and organic and inorganic metal-containing compounds other than oxides and carbonates of magnesium and calcium (c), though the use of such a compound is not essential.
~ The polyoxymethylene composition according to the ,~ present invention may further contain various known :,' :
:.. , .:
- 13 - ~ ~
,; :
213601 ~
additives. Examples of the additives include varlous colorants, slip additlve, mold release agent, nucleating agent, antistatic agent, weathering (light) stabilizer, other surfactants and various polymers.
The polyoxymothylene composition may contain one or more fillers selected from among known inorganic, organic and metallic, fibrous, flaky and powdery ones, as far as the performance of the obJective molded article according to the present invention is not remarkably lowered. Examples of such inorganic fillers include glass fiber, potassium titanate fiber, glass bead, talc, mica, muscovite and wollastonite, though the inorganic fillers are not limited to them.
The molded polyoxymethylene article of the present invention can be easily produced by the conventional processes for produc:Lng rrlolded resln artleles. ~;'or example, it can be produced by a process which comprises mixing necessary components with each other, kneading and extruding the obtained mixture with a single- or twin-screw extruder, mixing (diluting) a predetermined amount of the obtained pellets with polyoxymethylene pellets, and molding the pellet mixture to form an article having an objective composition. Further, it is preferable from the viewpoint of dispersibility of the additives that the ~- - 14 --` ', :~ .
-: . - , ~
composition be prepared by preliminarily pulverizing part or the whole of the acetal resin used as the base, mixing the resulting resin powder with the rest of the components, and extruding the obtained mixture.
As apparent from the above description and experimental examples, when the amount of the formic acid generated from the article comprising the resin composition of the present invention is 1.0 ~g/cm2 or below, it is apparent that the polyacetal resi~ molded article little influences the blooming of the rubber part. According to the present invention, as described above, the amount of the formic acid generated from a molded article can be reduced to 1.0 ~g/cm2 or below, which makes it possible to solve the problem of blooming of the rubber part fundamentally.
Therefore, the composltlon o~ the preserlt invention can be favorably used in various fields as described above.
Although the resin composition of the present invention can be applied to any field wherein formic acid causes troubles, it is favorably applied to fields (uses) wherein the components made at least partially from a rubber or a magnetic metal material coexist with a molded polyoxymethylene article, for ~i, example, electrical and electronic equipment, ' ~ - 15 -,~
. , particularly, audio or video apparatus. Specific examples thereof are as follows.
The electrical and electronic equipment which comprises at least a molded polyoxymethylene article and a rubber part or which comprises a molded polyoxymethylene article and has many metal contacts includes audio apparatus such as a cassette tape recorder; video apparatus such as a video tape recorder (VTR), 8-mm video and video camera; office automation (OA) machines such as a copying machine, facsimile, printer and word processor; toys driven by motor, spiral spring or other driving force; and keyboards of a telephone, computer and so forth.
Examples of the specific components to be made from the polyoxymethylene composition include a chassis (base plate), gear, lever, cam pulley and bearing.
The soft for optical or magnetic media which is at least partially constituted of a molded .
. . .
polyoxymethylene article includes a thin-metal-film-type magnetic tape cassette, magnetic disk cartridge, , magneto-optical disk cartridge and optical disk 1J cartridge. Particular examples thereof include a music metal tape cassette, digital audio tape :i : .:
cassette, 8-mm video tape cassette, floppy disk ~ cartridge and minidisk cartridge. Specific examples .
~ 16 -:~ :
~ ., of the component to be made from the polyoxymethylene composition include the body, reel, hub, guide, roller, stopper and lid of a tape cassette; and the body (case), shutter, hub and clamping plate of a disk cartridge.
Further, the molded polyoxymethylene article of the present invention can be favorably used as an automobile part in contact with metal, represented by a carrier plate of a wind regulator, the part of automobile fuel or electric system, a medical device such as a holder of hypodermic needle, or daily needs such as a water purifier, spray nozzle or spray container.
[Examples]
The present invention will now be described in detail by referring to the Yollowing Examples, though the present invention is not limited to them.
In the Examples, each composition was evaluated by the following methods:
1) Amount of formic acid generated from molded article I The amount of the formic acid generated from each molded polyoxymethylene article was determined by :
` putting a test piece (total surface area: about 10 cm2, weight: 10 g) prepared by cutting the article in a .~, :, h ~
2136010 ~
, , .
hermetically sealed container (capacity: 100 ml) containing 1 ml of pure water in such a way that the piece was not immersed in the water directly, allowing the test piece to stand as such under the conditions of 60C and 90% RH for 168 hours, diluting the resulting aqueous solution to 100 ml, and analyzing the diluted solution for formic acid concentration by ion chromatography [IC500 mfd. by Yokogawa-Hewlett-Packard, Ltd., column for organic acids. 0.1 mM
aqueous solution of perchloric acid (as the carrier)].
The amount of the formic acid generated per unit ~ :
surface area of the test piece was calculated from the formic acid concentration determined by the ion chromatography and shown in Table 1. .
z ) slOOming Or rubber An electromechanical component for reproducing sound and image which comprised a chassis fitted with :
a molded polyoxymethylene article and a rubber part incorporated therein was enclosed in a polyethylene bag and subjected to the blooming test under high-temperature and high-humidity conditions according to the procedure which will be described below to determine the amount of bloom on the surface of the resulting rubber part microscopically. The amounts of bloom thus determined were classified into ten ranks ;
: d 18 -~ ,,... L; ,"~ .", ~, , :, " "
~3~010 and the relationship between the amount of the b]oom and the amount of the formic acid generated is shown in the Table.
A roller produced by molding a chloroprene rubber into a cylinder was used as the rubber part and incorporated in a polyoxymethylene chassis of an electromechanical component for reproducing sound and image. The component was allowed to stand in a state enclosed in a polyethylene bag in an atmosphere of 60C and 90% RH for one week. The resulting rubber roller was examined for blooming microscopically. The extents of blooming thus determined were classified into ten ranks (numeral 1 refers to "no bloom", while numeral 10 refers to "extremely much bloom"). This test was conducted three times per each system and the average of the three ranks is glven in the Table.
3) Moldability (amount of mold deposit) A sample polyacetal resin composition was continuously molded on an injection molding machine into articles of a specific shape under the conditions which will be described below for 24 hours to determine the amount of mold deposit. Precisely, the mold used in the continuous molding was evaluated for contamination with the naked eye. The extents of contamination thus determined were classified into the .
. I :
2~3601~ :
, .
following five ranks.
(Molding conditions) injection molding machine: Toshiba IS30EPN (mfd. by Toshiba Machine Co., Ltd.), cylinder temp.: 210C, inJection pressure: 750 kg/cm2, injection time: 4 sec, cooling time: 3 sec, and mold temp.: 30C.
A B C D E
extremely much little (deposit over the whole surface) Examples 1 to 11 To a polyoxymethylene copolymer (a product of Polyplastic Co., Ltd., Duracon) was added an antioxidant, an amine polymer, oxide or carbonate of magnesium or calcium and, further, a fatty acid ester listed in the Table 1 each in amounts specified in the Table 1 (per 100 parts by weight of the polyoxymethylene). The resulting mixture was mixed and pelletized compositions were obtained with an extruder. The pelletized compositions thus prepared I were evaluated for the above properties. The results .~ ' 3 ~
i ' 2~36010 .
are given in the Table 1.
Compzrative Examples 1 to 7 For comparison, as shown in the Table 1, pelletized compositions were prepared in the same manner as that of the Example 1 except that neither metal oxide nor metal carbonate was added or that a metal oxide outside the scope of the present invention was added. The pelletized compositions were evaluated for the above properties. The results are given in the Table 1.
The antioxidants, amine polymers, metal oxides and metal carbonate used are as follows:
1. antioxidant a) 2,2'-methylenebis(4-methyl-6-t-butylphenol) and b) pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].
2. amine polymer b-1) polyacrylamide (m.w.: 500000) and b-2) polyallylamine (m.w.: 20000).
3. metal oxide and metal carbonate c-1) magnesium oxide, c-2) calcium oxide, ~ c-3) magnesium carbonate I c'-1) barium oxide, and ,~
.,~ .
'il ~' , c'-2) zinc oxide.
4. fatty acid ester d-1) glycerol monostearate and d-2) glycerol monoisostearate. ~ .
[Disclosure of the Invention]
In order to solve the above problems, the inventors of the present invention have made detailed studies on the blooming of the rubber part and the corrosion of the magnetic metal article to -find that the material of the electromechanical component of an audio or video apparatus relates closely to the problems. More precisely, it has been -found that the molded polyoxymethylene article used mainly as an electromectlanical component of' an audio or video apparatus, such as a chassis (base plate), gear or bearing, a part of a tape cassette, such as a reel or guide roll, or a part of a disk cartridge, such as a shutter or cartridge body causes the blooming of a rubber part such as a roller or belt or the corrosion of a magnetic metal article under relatively high-temperature and high-humidity conditions. Further, studies have been made on the reason for this ~t . problematic phenomenon to find that the formic acid ,1 .
,~J " .
213~010 contained in the molded polyoxymethylene article is ~
released through the medium of water contained in a high-humidity atmosphere to adhere to the rubber part and the magnetic metal article and penetrate into them, and that the formic acid penetrating into the rubber part reacts with the difficultly water-soluble magnesium oxide contained in the rubber to form easily water-soluble magnesium formate, which bleeds to the surface of the rubber part to contaminate the magnetic head through a tape, while the formic acid penetrating into the magnetic metal article corrodes the metal.
Although polyoxymethylene is improved in heat ~ ~
stability by the addition o~ an antioxidant and ::
various stabilizers as described above, it cannot ~:
avoid being thermally decomposed a little in processing and molding, so that the molded article thereof conta:Lns formaldehyde and formic acid which are the products of decomposition. The formaldehyde is released around as a gas when the molded article is heated to tens of degrees centigrade or above, so that ~;
the amount of formaldehyde remaining in the molded ~ :
article can be reduced remarkably by subjecting the article to high-temperature treatment or vacuum degassing, while the amount of the formic acid conteined in the article can little be reduced even by ,~ .
2~L36010 treating it at a temperature of as high as one hundred and tens of degrees centigrade or in hot water.
The inventors of the present invention have further made studies to overcome this disadvantage, and have found that the amount of the formic acid generated from a molded polyoxymethylene article can be remarkably reduced by the addition of an antioxidant, a specific amine polymer and a specific metallic compound. The present invention has been accomplished on the basis of this finding.
Thus, the present invention relates to a po]yoxymethylene composition prepared by blending 100 parts by weight of polyoxymethylene with (a) 0.01 to 5.0 parts by weight of an antioxidant, (b) 0.01 to 5.0 parts by weight of an amine polymer havlng amino groups on its side chains as represented by the general formula (I) and (c) 0.001 to 10 parts by weight of at least one metal-containing compound selected from among oxides and carbonates of magnesium and calcium, and a molded polyoxymethylene article produced by molding the composition, characteri~ed in that the amount of the formic acid generated from the molded article of the polyoxymethylene composition is ,~ 1.0 ~g or below per square centimeter of the surface area of the molded article.
,,!
.... . .
,. . .
. .~ . , : : -. :,.,,i. . : : .::
,."~, . : : , . - :-:; :
,: i: . .
.. :
2~31~0~0 H R
_ C-C - - tl) H X
N~2 [wherein R represents a hydrogen atom, an alkyl group, a phenyl group, an alkyl-substituted phenyl group or 1~2 X-; and X represents an alkylene group, a carbonyl group, a carboxyalkylene group, an alkyleneoxy-carbonylalkyl group, a phenylene group, an alkyl-substituted phenylene group, an amido group or an alkyleneamido group or nil.]
The present invention will now be described in detail.
The polyoxymethylene to be used in the present invention is a polymer mainly composed of oxymethylene (-CH20-) units, which may be either a polyoxymethylene homopolymer or a copolymer, terpolymer or block copolymer containing small amounts of other constituent units )n addition to the oxymethylene units. Further, these (co)polymers may be linear, -~
branched or crosslinked. Furthermore, the degree of polymerization thereo~ is not particularly limited.
The antioxidant (a) to be used in the present `!
~ - 7 -invention includes hindered phenols such as 2,2'-methylenebis(4-methyl-6-t-butylphenol), 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetrakis[3-(3,5-di-t-buty1-4-hydroxyphenyl)propionate~, triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], ~ :
1,3,5-trimethyl-2,2,6--tris(3,5-di-t-butyl-4-hydroxy-benzyl)benzene, n-octadecyl 3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-butylidenebis(6-t-butyl-3-methyl-phenol), distearyl 3,5-di-t-butyl-4-hydroxybenzyl-phosphonate, 2-t-butyl-6-(3-t-butyl-5-methyl-2-hydioxybenzyl-4-methylphenyl acrylate and N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydro-cin~amamlde; and phosphorus antioxidants such as triphenyl phosphite, trisnonylphenyl phosphite, tris(Z,4-di-t-butylphenyl) phosphite, tris(2-t-buty1-4-methylphenyl) phosphite, tris(Z,4-di-t-amylphenyl) phosphite, , tris(2-t-butylphenyl) phosphite, tris(2-t-phenylphenyl) phosphite, tris(2-(1,1-dimethylpropyl)-phenyl) phosphite, tris(2,4-(1,1-dimethylpropyl)-. phenyl) phosphite, tris(2-cyclohexylphenyl) phosphite and tris(2-t-butyl-4-phenylphenyl) phosphite. In addition, hindered amine antioxidants can also be : - 8 -:,~
.`,`', . ', .',''~i' '' ' ''' ' ' ~ ' . . ~ ' : , .. . . .
'." "` ' ~ . : ' ' ''',, ' ' , ' : ' ' ~ "
used, and one or two or more of these may be used.
Among them, 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~ and N,N'-hexamethylenebis-(3,5-di-t-butyl-4-hydroxyhydrocinnamamide) are particularly preferable substances.
Although the amine polymer (b) to be used in the present invention may be any one comprising constituent units represented by the above general formula (1), it is preferably a homoplymer, corosslinked polymer or copolymer having a molecular weight of 1000 or above and composed of constituent , units derived from one or more monomers selected from i among allylamine, acrylamide, acrylohydrazide, methacrylohyclrazide, aminoalkyl acrylate, aminoalkyl :1 , methacrylate, vinylalkylamine and so forth, or a copolymer comprising one or more of the above amine monomers and one or more monomers selected from among : ethylene, propylene, butylene, butadiene, styrene, acrylonitrile, acrylic acid esters, methacrylic acid esters and so forth. These amine polymers may be used alone or as a mixture of two or more of them.
The molecular weight of the amine polymer to be '~
,~. _ g _ , used in the present invention is preferably 1000 or above, still preferably 10000 to 100000. When the molecular weight is too low, the resulting composition or molded article will suffer from the bleeding of the amine polymer and the obJective effect of the present invention will not be attained.
Among the above amine polymers, it is preferable ~-to use a homopolymer, crosslinked polymer or copolymer having a molecular weight of 1000 or above and comprising constituent units derived from allylamine or acrylamide.
According to the present invention, the amount of the antioxidant (a) to be added is 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight per 100 j parts by weight of the pol.yoxyrnethylene, whlle the amount of the amine polymer (b) is 0.01 to 5 parts by weight, preferably 0.01 to 1 part by weight per 100 parts by weight thereof. When the amounts of these components are too small, no sufficient effect will be attained, while when they are too large, no additional improvement in the heat stability will be attained, rather, the resulting composition will be liable to discolor unfavorably.
The metal-containing compound (c) to be used in the present invention is an oxide or carbonate of 'i - 10 - ' . !
!
:' :
~ ~ .
21360~0 magnesium or calcium, particularly, magnesium oxide, calcium oxide, magnesium carbonate or calcium carbonate.
The amount o~ these compound to be added i5 0 . 00 to 10 parts by weight, desirably 0.001 to 5 parts by weight, more desirably 0.001 to 2 parts by weight, most desirably 0.003 to 0.5 part by weight per 100 parts by weight of the polyoxymethylene. When the amount is less than 0.001 part by weight, the objective effect will little be attained, while when it exceeds 10 parts by weight, no additional reduction in the amount of the formic acid generated will be attained, rather, the resulting composition will be liable to discolor unfavorably.
The metal-contalning compound (c) and the antioxidant (a) may be aaded either to the monomer(s) ln the polymerization step or in the step of stabilizing t;he polymer.
It is pr-eferable that the polyoxymethylene composition of the present invention further contain a fatty acid ester having at least 10 carbon atoms, still preferably a fatty acid ester of a polyhydric alcohol -~or the purpose of minimizing the mold deposit formed during molding. Examples of such a compound ., '! include glycerol monopalmitate, glycerol monostearate, !
", '; - 11 -l :
~136010 glycerol monoisostearate, glycerol monobehenate and pentaerythritol tristearate. The amount of the ester to be added is 0.01 to 2.0 parts by weight, preferably 0.05 to 1.0 part by weight per 100 parts by weight of the polyoxymethylene.
The determination method of the amount of the formic acid generated will be described. It is effected by molding the above composition, cutting the moled article at need, measuring the surface area thereof, putting a proper amount (corresponding to a surface area of about 30 to 60 cm2) of the molded article in a hermetically sealed container (capacity:
100 ml) containing 1 ml of pure water in such a way that the molded article is not immersed in the water directly, allowing the molded article to stand as such at 60C for 168C, diluting the resulting aqueous solution in the hermetically sealed container to 100 ml, analyzing this solution for formic acid concentration (~g) by ion chromatograph (IC500 mfd. by Yokogawa-Hewlett-Packard, Ltd., column for organic acid, 0.1 mM aqueous solution of perchloric acid as the carrier), and calculating the amount of the formic acid generated per unit surface area of the molded article (~g/cm2).
The preferable molded polyoxymethylene article 'i, "' l - 12 --- 213~0~0 according to the present invention is one generating formic acid in an amount of at most 1.0 ~g per square centimeter of the surface area thereof, particularly preferably one generating formic acid in an amount of at most 1.0 ~g per square centimeter of the surface area and in an amount of at most 5.0 ~g per g of the resin component. The numerical regulation on the amount of the formic acid generated according to the present invention can be applied to not only articles molded from polyoxymethylene compositions containing conventional additives such as ordinary stabilizers and/or mold release agent, but also ones molded from polyoxymethylene compositions containing inorganic fillers and/or other polymers, as far as polyoxy-methylene occupies most of the surface thereof.
The polyoxymethylene composltion o~ the present invention may further contain one or more members selected frorrl among nitrogen-containing compounds other than the amine polymers (b) according to the present invention and organic and inorganic metal-containing compounds other than oxides and carbonates of magnesium and calcium (c), though the use of such a compound is not essential.
~ The polyoxymethylene composition according to the ,~ present invention may further contain various known :,' :
:.. , .:
- 13 - ~ ~
,; :
213601 ~
additives. Examples of the additives include varlous colorants, slip additlve, mold release agent, nucleating agent, antistatic agent, weathering (light) stabilizer, other surfactants and various polymers.
The polyoxymothylene composition may contain one or more fillers selected from among known inorganic, organic and metallic, fibrous, flaky and powdery ones, as far as the performance of the obJective molded article according to the present invention is not remarkably lowered. Examples of such inorganic fillers include glass fiber, potassium titanate fiber, glass bead, talc, mica, muscovite and wollastonite, though the inorganic fillers are not limited to them.
The molded polyoxymethylene article of the present invention can be easily produced by the conventional processes for produc:Lng rrlolded resln artleles. ~;'or example, it can be produced by a process which comprises mixing necessary components with each other, kneading and extruding the obtained mixture with a single- or twin-screw extruder, mixing (diluting) a predetermined amount of the obtained pellets with polyoxymethylene pellets, and molding the pellet mixture to form an article having an objective composition. Further, it is preferable from the viewpoint of dispersibility of the additives that the ~- - 14 --` ', :~ .
-: . - , ~
composition be prepared by preliminarily pulverizing part or the whole of the acetal resin used as the base, mixing the resulting resin powder with the rest of the components, and extruding the obtained mixture.
As apparent from the above description and experimental examples, when the amount of the formic acid generated from the article comprising the resin composition of the present invention is 1.0 ~g/cm2 or below, it is apparent that the polyacetal resi~ molded article little influences the blooming of the rubber part. According to the present invention, as described above, the amount of the formic acid generated from a molded article can be reduced to 1.0 ~g/cm2 or below, which makes it possible to solve the problem of blooming of the rubber part fundamentally.
Therefore, the composltlon o~ the preserlt invention can be favorably used in various fields as described above.
Although the resin composition of the present invention can be applied to any field wherein formic acid causes troubles, it is favorably applied to fields (uses) wherein the components made at least partially from a rubber or a magnetic metal material coexist with a molded polyoxymethylene article, for ~i, example, electrical and electronic equipment, ' ~ - 15 -,~
. , particularly, audio or video apparatus. Specific examples thereof are as follows.
The electrical and electronic equipment which comprises at least a molded polyoxymethylene article and a rubber part or which comprises a molded polyoxymethylene article and has many metal contacts includes audio apparatus such as a cassette tape recorder; video apparatus such as a video tape recorder (VTR), 8-mm video and video camera; office automation (OA) machines such as a copying machine, facsimile, printer and word processor; toys driven by motor, spiral spring or other driving force; and keyboards of a telephone, computer and so forth.
Examples of the specific components to be made from the polyoxymethylene composition include a chassis (base plate), gear, lever, cam pulley and bearing.
The soft for optical or magnetic media which is at least partially constituted of a molded .
. . .
polyoxymethylene article includes a thin-metal-film-type magnetic tape cassette, magnetic disk cartridge, , magneto-optical disk cartridge and optical disk 1J cartridge. Particular examples thereof include a music metal tape cassette, digital audio tape :i : .:
cassette, 8-mm video tape cassette, floppy disk ~ cartridge and minidisk cartridge. Specific examples .
~ 16 -:~ :
~ ., of the component to be made from the polyoxymethylene composition include the body, reel, hub, guide, roller, stopper and lid of a tape cassette; and the body (case), shutter, hub and clamping plate of a disk cartridge.
Further, the molded polyoxymethylene article of the present invention can be favorably used as an automobile part in contact with metal, represented by a carrier plate of a wind regulator, the part of automobile fuel or electric system, a medical device such as a holder of hypodermic needle, or daily needs such as a water purifier, spray nozzle or spray container.
[Examples]
The present invention will now be described in detail by referring to the Yollowing Examples, though the present invention is not limited to them.
In the Examples, each composition was evaluated by the following methods:
1) Amount of formic acid generated from molded article I The amount of the formic acid generated from each molded polyoxymethylene article was determined by :
` putting a test piece (total surface area: about 10 cm2, weight: 10 g) prepared by cutting the article in a .~, :, h ~
2136010 ~
, , .
hermetically sealed container (capacity: 100 ml) containing 1 ml of pure water in such a way that the piece was not immersed in the water directly, allowing the test piece to stand as such under the conditions of 60C and 90% RH for 168 hours, diluting the resulting aqueous solution to 100 ml, and analyzing the diluted solution for formic acid concentration by ion chromatography [IC500 mfd. by Yokogawa-Hewlett-Packard, Ltd., column for organic acids. 0.1 mM
aqueous solution of perchloric acid (as the carrier)].
The amount of the formic acid generated per unit ~ :
surface area of the test piece was calculated from the formic acid concentration determined by the ion chromatography and shown in Table 1. .
z ) slOOming Or rubber An electromechanical component for reproducing sound and image which comprised a chassis fitted with :
a molded polyoxymethylene article and a rubber part incorporated therein was enclosed in a polyethylene bag and subjected to the blooming test under high-temperature and high-humidity conditions according to the procedure which will be described below to determine the amount of bloom on the surface of the resulting rubber part microscopically. The amounts of bloom thus determined were classified into ten ranks ;
: d 18 -~ ,,... L; ,"~ .", ~, , :, " "
~3~010 and the relationship between the amount of the b]oom and the amount of the formic acid generated is shown in the Table.
A roller produced by molding a chloroprene rubber into a cylinder was used as the rubber part and incorporated in a polyoxymethylene chassis of an electromechanical component for reproducing sound and image. The component was allowed to stand in a state enclosed in a polyethylene bag in an atmosphere of 60C and 90% RH for one week. The resulting rubber roller was examined for blooming microscopically. The extents of blooming thus determined were classified into ten ranks (numeral 1 refers to "no bloom", while numeral 10 refers to "extremely much bloom"). This test was conducted three times per each system and the average of the three ranks is glven in the Table.
3) Moldability (amount of mold deposit) A sample polyacetal resin composition was continuously molded on an injection molding machine into articles of a specific shape under the conditions which will be described below for 24 hours to determine the amount of mold deposit. Precisely, the mold used in the continuous molding was evaluated for contamination with the naked eye. The extents of contamination thus determined were classified into the .
. I :
2~3601~ :
, .
following five ranks.
(Molding conditions) injection molding machine: Toshiba IS30EPN (mfd. by Toshiba Machine Co., Ltd.), cylinder temp.: 210C, inJection pressure: 750 kg/cm2, injection time: 4 sec, cooling time: 3 sec, and mold temp.: 30C.
A B C D E
extremely much little (deposit over the whole surface) Examples 1 to 11 To a polyoxymethylene copolymer (a product of Polyplastic Co., Ltd., Duracon) was added an antioxidant, an amine polymer, oxide or carbonate of magnesium or calcium and, further, a fatty acid ester listed in the Table 1 each in amounts specified in the Table 1 (per 100 parts by weight of the polyoxymethylene). The resulting mixture was mixed and pelletized compositions were obtained with an extruder. The pelletized compositions thus prepared I were evaluated for the above properties. The results .~ ' 3 ~
i ' 2~36010 .
are given in the Table 1.
Compzrative Examples 1 to 7 For comparison, as shown in the Table 1, pelletized compositions were prepared in the same manner as that of the Example 1 except that neither metal oxide nor metal carbonate was added or that a metal oxide outside the scope of the present invention was added. The pelletized compositions were evaluated for the above properties. The results are given in the Table 1.
The antioxidants, amine polymers, metal oxides and metal carbonate used are as follows:
1. antioxidant a) 2,2'-methylenebis(4-methyl-6-t-butylphenol) and b) pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].
2. amine polymer b-1) polyacrylamide (m.w.: 500000) and b-2) polyallylamine (m.w.: 20000).
3. metal oxide and metal carbonate c-1) magnesium oxide, c-2) calcium oxide, ~ c-3) magnesium carbonate I c'-1) barium oxide, and ,~
.,~ .
'il ~' , c'-2) zinc oxide.
4. fatty acid ester d-1) glycerol monostearate and d-2) glycerol monoisostearate. ~ .
5. other compound .-e-1) polyamide (nylon 6-6). :
~5 .
J
;i ,~ .
:~ - 22 -.' 21360~0 _ _ _ _ ~, m o ~ ~' o _ o o _ _ _l u~ o O _ o ~ m . U~ C~ U~ o ' _, oo ~
Ei _ a~ o ,~ o ~ o ~ Q
C~ _ ~ ,lr C'~o _ _ O, O --=0 O'q 'O-' _ O ~ 1~
_ _ _I U~ D O c~ c~ _ ::
_~ _l U~ D O _, O O ~i _ O C~ U~ ~ _~ _ O
~ (~ _IU~ .-IU~ _,0 O O
E~ _ 0 ~ O _~ _ ~ c~ _ r o ,o o ~ c~l u~ _ o o c _ _1 u~ ~ o _~ ~ O O _ U~ ~l U~ .~o o ,,,, o _ ~ l_ ~
_ _ ~r ~0 Uo ~0 ~ ~ O _ 00. C~ c:~
_ _ C~ _~ U~ ~ U O ~o o ~
C~ _lu~ ~ _~ o _~
~i 0 0 D O _l o O t--_ _ ~ = 1. ~ ~ o ~ ~ .-i e0 ~ ;~ ~, ~ ~ L. ~ ~ q~ ~ O O .' i y e ~ 0 v ~ 3 o q~ e e ~ a .J~. - C ` ` ~ D. 1~ ~ ~ o ~ E~ ~!; 0 ~ O.~ ~0 :
~5 .
J
;i ,~ .
:~ - 22 -.' 21360~0 _ _ _ _ ~, m o ~ ~' o _ o o _ _ _l u~ o O _ o ~ m . U~ C~ U~ o ' _, oo ~
Ei _ a~ o ,~ o ~ o ~ Q
C~ _ ~ ,lr C'~o _ _ O, O --=0 O'q 'O-' _ O ~ 1~
_ _ _I U~ D O c~ c~ _ ::
_~ _l U~ D O _, O O ~i _ O C~ U~ ~ _~ _ O
~ (~ _IU~ .-IU~ _,0 O O
E~ _ 0 ~ O _~ _ ~ c~ _ r o ,o o ~ c~l u~ _ o o c _ _1 u~ ~ o _~ ~ O O _ U~ ~l U~ .~o o ,,,, o _ ~ l_ ~
_ _ ~r ~0 Uo ~0 ~ ~ O _ 00. C~ c:~
_ _ C~ _~ U~ ~ U O ~o o ~
C~ _lu~ ~ _~ o _~
~i 0 0 D O _l o O t--_ _ ~ = 1. ~ ~ o ~ ~ .-i e0 ~ ;~ ~, ~ ~ L. ~ ~ q~ ~ O O .' i y e ~ 0 v ~ 3 o q~ e e ~ a .J~. - C ` ` ~ D. 1~ ~ ~ o ~ E~ ~!; 0 ~ O.~ ~0 :
Claims (7)
1. A polyoxymethylene composition prepared by blending 100 parts by weight of a polyoxymethylene with (a) 0.01 to 5.0 parts by weight of an antioxidant, (b) 0.01 to 5.0 parts by weight of an amine polymer having amino groups on its side chains as represented by the general formula (I) and (c) 0.001 to 10 parts by weight of at least one metal-containing compound selected from among oxides and carbonates of magnesium and calcium:
(1) [wherein R represents a hydrogen atom, an alkyl group, a phenyl group, an alkyl-substituted phenyl group or ; and X represents an alkylene group, a carbonyl group, a carboxyalkylene group, an alkyleneoxy-carbonylalkyl group, a phenylene group, an alkyl-substituted phenylene group, an amido group or an alkyleneamido group or nil.]
(1) [wherein R represents a hydrogen atom, an alkyl group, a phenyl group, an alkyl-substituted phenyl group or ; and X represents an alkylene group, a carbonyl group, a carboxyalkylene group, an alkyleneoxy-carbonylalkyl group, a phenylene group, an alkyl-substituted phenylene group, an amido group or an alkyleneamido group or nil.]
2. The polyoxymethylene composition as set forth in claim 1, wherein the amine polymer (b) is one or more members selected from among homopolymers, crosslinked polymers and copolymers of allylamine.
3. The polyoxymethylene composition as set forth in claim 1, wherein the amine polymer (b) is one or more members selected from among homopolymers, crosslinked polymers and copolymers of acrylamide.
4. The polyoxymethylene composition as set forth in any of claims 1 to 3, which is prepared by further blending a fatty acid ester having 10 or more carbon atoms in an amount of 0.01 to 2.0 parts by weight per 100 parts by weight of the polyoxymethylene.
5. A molded polyoxymethylene article produced by molding the composition as set forth in any of claims 1 to 4, characterized in that the amount of the formic acid generated from the molded article of the polyoxymethylene composition is 1.0 µg or below per square centimeter of the surface area of the molded article.
6. The molded polyoxymethylene article as set forth in claim 5, wherein the molded article is a part of electrical or electronic equipment.
7. An electrical or electronic equipment containing the molded polyoxymethylene article as set forth in claim 6 and a part made from a rubber as the parts of its constituent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20921493A JPH0762199A (en) | 1993-08-24 | 1993-08-24 | Polyoxymethylene composition and molded product thereof |
| JP5-209214 | 1993-08-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2136010A1 true CA2136010A1 (en) | 1994-11-16 |
Family
ID=16569244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2136010 Abandoned CA2136010A1 (en) | 1993-08-24 | 1994-08-23 | Polyoxymethylene composition and molded article thereof |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH0762199A (en) |
| BR (1) | BR9404966A (en) |
| CA (1) | CA2136010A1 (en) |
| WO (1) | WO1995006087A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09235448A (en) * | 1996-02-28 | 1997-09-09 | Polyplastics Co | Polyoxymethylene composition |
| DE19725054A1 (en) * | 1997-06-13 | 1998-12-17 | Basf Ag | Molding compounds resistant to sliding friction |
| US20040242747A1 (en) * | 2003-05-30 | 2004-12-02 | Malay Nandi | Polyoxymethylene homopolymer with improved thermal stability |
| JP4730948B2 (en) * | 2005-08-03 | 2011-07-20 | 旭化成ケミカルズ株式会社 | Polyacetal resin composition |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3901605A1 (en) * | 1989-01-20 | 1990-07-26 | Basf Ag | POLYOXYMETHYLENE MOLDING |
-
1993
- 1993-08-24 JP JP20921493A patent/JPH0762199A/en active Pending
-
1994
- 1994-08-23 WO PCT/JP1994/001387 patent/WO1995006087A1/en active Application Filing
- 1994-08-23 CA CA 2136010 patent/CA2136010A1/en not_active Abandoned
- 1994-08-23 BR BR9404966A patent/BR9404966A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0762199A (en) | 1995-03-07 |
| WO1995006087A1 (en) | 1995-03-02 |
| BR9404966A (en) | 1999-06-15 |
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