CN1053436A - stable polyacetal composition - Google Patents

Abstract

Containing avicel cellulose or fibrous cellulose does the improvement of the polyacetal composition thermostability of melt-processed stablizer and reaches as poly-(ethylidene vinyl alcohol) by adding polyamide-based co-stabilizer or melting hydroxyl polymer-containing or oligopolymer co-stabilizer simultaneously.Containing formaldehyde reactive nitrogen base or activity hydroxy and average particle size is at least aly to contain the phenol type antioxidant of acid amide or add at least a melting co-stabilizer compound (as common polyacetal stabilizer) simultaneously and primary antioxidant reaches by adding less than the improvement of the polyacetal composition thermostability of 10 microns not molten polymer stablizer.The feature of the present composition is to have good melt-processed stability and long-term thermal stability.

Description

Stable polyacetal composition

Recently, people have developed the stablizer of various novel polyacetal compositions (being also referred to as polyoxymethylene compositions usually).These novel stabilizers are avicel celluloses, fibrous cellulose, contain formaldehyde activity hydroxy or formaldehyde reactive nitrogen base or not molten polymer that both have both at the same time, these novel stabilizers are given polyacetal composition improved melt processing stability than common nylon stabilizer.

Have found that the polyacetal composition that contains these new stable agent, its thermal stability is further improved.Especially with micro-crystallization or the stable polyacetal composition of fibrous cellulose, according to hot release formaldehyde test determination result, wherein contain the composition of certain polyamide-based stablizer and certain fusible hydroxyl stablizer, its melt-processed stability is further improved.Contain the stable polyacetal composition of not molten polymer stablizer that formaldehyde reactive nitrogen base or formaldehyde activity hydroxy or both have both at the same time for using, according to air oven weathering test measurement result, by adding the phenol type antioxidant of at least a amide containing, perhaps when adding at least a main stabilizer, add at least a common polyacetal thermo-stabilizer, can further improve the permanent stability of described composition, this will describe in further detail hereinafter.

No matter be that requirement increases melt-processed stability or requirement permanent stability, composition of the present invention all is useful.

The reference of enumerating below is as the background technology with the stable polyacetal composition of the present invention of Mierocrystalline cellulose.

United States Patent (USP) 4,766,168 polymkeric substance or the oligopolymers that disclose hydroxyl are made polyacetal stabilizer.Not concrete openly micro-crystallization and fibrous cellulose in this reference, they both are infusible under the melt processing temperature of polyacetal.And, in this reference, do not have to confirm owing to these advantages of having used specific stabilizer blend to obtain in the present invention.

United States Patent (USP) 4,722,662 have disclosed the method for the stable oxidation methylene radical multipolymer of preparation heat resistanceheat resistant degraded, described method is included in this multipolymer of heating in the medium that contains water and two substituted cellulose ethers, make the hydrolysis of unsettled oxidation methylene radical end group, from the water medium that contains two substituted cellulose ethers, isolate oxidation methylene radical multipolymer then.Disubstituted ether of cellulose is known thermoplastics.

United States Patent (USP) 4,111,887 disclose the polyoxymethylene molding materials that physicals has been improved, and it contains a kind of teracol based polyalcohol, the mixture of a kind of fibrous reinforcement material (it can comprise cellulosic fibre) and a kind of polycarbodiimide.

United States Patent (USP) 3406129 discloses the mouldable cellulose polymer compound that contains free hydroxyl group and molten mixture up to 50% acetal polymer, United States Patent (USP) 3406130 discloses the colloidal dispersants of such mixture, it contains some solvent of cellulose polymer compound, it is said that these compositions have melt strength and the elongation that has improved.United States Patent (USP) 3406129 particularly points out use greater than 50%(weight) polyacetal is deleterious to this molten mixture.Disclosed Mierocrystalline cellulose is not an avicel cellulose in these reference, because it is mouldable, therefore it is a fusile under the melt processing temperature of polyacetal.

Some reference discussed above discloses and mixed some special Mierocrystalline cellulose in polyacetal composition, but do not disclose the specific Mierocrystalline cellulose that composition of the present invention uses, do not reveal that micro-crystallization or fibrous cellulose are used in combination the thermostability of improving polyacetal composition with at least a co-stabilizer compound yet.

The reference of enumerating below as with the stable improvement of molten polymer not the background technology of polyacetal composition of the present invention.

United States Patent (USP) 4098843 discloses the polyoxymethylene compositions that contains dispersion agent, this dispersion agent is that (1) melt temperature is greater than the about 25 ℃ semicrystalline polyamides of the fusing point of polyoxymethylene, or (2) second-order transition temperature is at least greater than the about 5 ℃ amorphous polyamides of the fusing point of polyoxymethylene, wherein any must being dispersed in the polymer support resin, this vector resin is under the polyoxymethylene melt processing temperature or be lower than fusion under this temperature.

United States Patent (USP) 4640949 discloses with the stable polyoxymethylene compositions of mixed stabilizer, this stabilizer blend is made up of 50-97% thermoplastic polyurethane and 3-50% polymeric amide, wherein polymeric amide is dispersed in the urethane, and the melt temperature of polymeric amide is higher than the fusing point of polyoxymethylene.

Japanese Unexamined Patent Publication No 42-7107 has disclosed the teracol based polyalcohol of the multipolymer that contains teracol based polyalcohol or its multipolymer and acrylamide and vinylbenzene or vinyl naphthalene or the composition of multipolymer.The fusing point of the multipolymer of requirement acrylamide and vinylbenzene or vinyl naphthalene is equal to or less than the fusing point of teracol based polyalcohol or multipolymer.

Japanese Unexamined Patent Publication No 43-14329 has disclosed a kind of method of stabilized oxymethylene polymkeric substance, and this yuban is made up of the adducts of the multipolymer of acrylamide or acrylamide derivative.

Japanese Unexamined Patent Publication No 59-213752 discloses and has contained the polyacetal composition that the poly-fine powder is made thermo-stabilizer, and wherein poly-is obtained by the acrylamide hydrogen transfer polymerization.Hydrogen transfer polymerization obtains poly-, and wherein a large amount of formaldehyde reactive nitrogen bases are in main polymer chain.

West Germany application publication number P3715117 discloses a kind of thermo-stabilizer of polyacetal, is the improvement to above-mentioned Japanese patent application publication No. 59-21375 reference.This piece reference discloses the thermo-stabilizer of making polyacetal with a kind of poly-compound.This poly-compound contains:

General formula-(CH ₂CH ₂CONH)-(X) monomeric unit and

General formula (Y) monomeric unit,

It is characterized in that with respect to the content range that whenever digests monomer adduct unit (Y) be 1.4-10mM, preferably 5-9mM.

United States Patent (USP) 4814397 discloses a kind of thermo-stabilizer of the polyacetal of being made up of following polymkeric substance and oligopolymer, and this polymkeric substance and oligopolymer contain the another kind of functional group of hydroxyl and at least a Lewis base stronger than hydroxyl simultaneously.The too high stablizer (from molecular weight and chemical constitution) of viscosity is unfavorable, because be difficult to this stablizer is dispersed in the polyacetal.

Above-named United States Patent (USP) 4766168 about the stable polyacetal composition of Mierocrystalline cellulose also discloses the thermo-stabilizer of the polyacetal of being made up of the oligopolymer of the polymkeric substance of hydroxyl and hydroxyl.The importance of stablizer granular size unconfirmed in this reference.

United States Patent (USP) 3204014 discloses the heat-stabilised poly acetal composition that contains polyacetal and following ternary stabiliser system, this ternary stabiliser system by (a) a kind of N-vinyl pyrrolidone and can with the multipolymer of the monoolefine monomer of its copolymerization, (b) a kind of phenol type antioxidant, (c) a kind of 3,3 '-dibasic acid esters of thio-2 acid forms.The importance of the not meltbility of the importance of this stablizer mean particle size unconfirmed or stablizer.

United States Patent (USP) 3219727 has disclosed owing to having added on side chain and has contained

The vinyl polymer that contains amide group and lactam group on the vinyl polymer of structural unit, particularly side chain obtains thermostability enhanced polyoxymethylene compositions.This reference is not confirmed the importance that average particle size is little, does not confirm that stablizer should be a fused not yet.

United States Patent (USP) 3235531 discloses a kind of method of stable oxidation methylene radical multipolymer.United States Patent (USP) 3210322 discloses a kind of processing by methylene oxide polymer, the method for the trioxane polymerisate that trioxane polymerizing catalyst and unreacted trioxane are formed.United States Patent (USP) 3236929 discloses a kind of injection molding method of oxidation methylene radical multipolymer.US3418280 discloses a kind of method of stablizing following polymkeric substance, and this polymkeric substance contains the monomeric unit of easy degraded, so be easy to thermal destruction.Just in four pieces of reference of narration, methylene oxide polymer or multipolymer can contain thermo-stabilizer in front, for example replace polyacrylamide or contain the compound of 1-6 amide group.

US4230606 has disclosed the thermo-stabilizer that melamine-formaldehyde condensation products is made polyoxymethylene.Its advantage is to form melamine-formaldehyde precondensate in the presence of one or more protectiveness colloidal state agent (can comprise acrylamide copolymer).The stablizer that acrylamide copolymer is a polyacetal is not proposed here.

US4522735 discloses poly-amino phosphorous acid ester oligopolymer as effective stabilizer, and the protection polymkeric substance is avoided thermal destruction.Polymer stabilizer is not disclosed.

US4555357 discloses and has contained polyacetal, carbon black and contain the polyacetal composition of the amide compound of 6 repeating units at most.

US4596847 discloses and has contained polyacetal, the polyacetal composition of carbon black and nonionogenic tenside.

US4657970 and US4657971 disclose the composition of being made up of at least a thermoplastic polymer (as polyoxymethylene) and at least a modified block copolymer, and this modified block copolymer is made up of aromatic polymer block A and at least a olefin polymer B block that at least a mono-vinyl replaces.The shock resistance of composition has been improved.

US3215671 discloses with UV-light and has made polyoxymethylene and the crosslinked method of mixture that is selected from by acid amides, ester and imido carboxylic-acid functional derivative.

US3281499 discloses the method that is prepared (comprising acrylamide) the teracol base co-polymer by the vinyl unsaturated comonomer.This patent is about preparation teracol base co-polymer, rather than stable polyoxymethylene.

US3338872 discloses the teracol base co-polymer that is made by formaldehyde and Acrylic Acid Monomer (as acrylamide and Methacrylamide).This patent relates to the preparation of teracol base co-polymer, rather than stable teracol base co-polymer.

US3366561 discloses the method for trioxane and copolymerisable monomer (can be acrylamide) polymerization production teracol base co-polymer.In this reference, do not approve or point out special parameter of the present invention.

US3470135 discloses in the presence of tetravalent tin organic compound catalyzer and has made oxymethylene polymerization, prepares the method for stable polyoxymethylene.

US3518326 discloses the thermosetting resin by acrylamide and formaldehyde-derived.But openly do not give the method for polyacetal thermostability.

US4464435 discloses by following (a), (b) and (c) polyacetal composition of forming, wherein: (a) polyacetal, (b) carbonate of II family metal in the periodictable, phosphoric acid salt, acetate or their mixture and (c) be selected from the polymkeric substance or the multipolymer of acrylamide or Methacrylamide etc.For preventing that molded product from forming the crack and adding component (c).Here do not mention in the melt-processed process and improve thermostability.

In the reference discussed above, there is not one piece to disclose specific embodiments of the present invention, especially open getable advantage when mixed stabilizer system of the present invention or special oxidation inhibitor are added in the polyacetal composition not.

The present invention relates to the Mierocrystalline cellulose stable polyacetal composition that thermostability has been improved.Particularly relate to and use 0.05-5%(weight) micro-crystallization or fibrous cellulose and 0.05-4%(weight) the stable polyacetal composition of at least a co-stabilizer compound, this co-stabilizer compound is selected from the co-stabilizer of polyamide-based and contains the fusible polymkeric substance of hydroxyl or the co-stabilizer of fusible oligopolymer, wherein, the mean particle size of avicel cellulose is 100 microns or littler, the melting polymkeric substance or the melting oligopolymer co-stabilizer that contain hydroxyl are essentially nonacid material, and above-mentioned weight percentage is with Mierocrystalline cellulose, the weight of co-stabilizer compound and polyacetal is the basis.The gained polyacetal composition, it is characterized in that having the thermostability of having improved, its thermostability on average surpasses polyacetal itself, separately with the stable polyacetal of polyamide-based stablizer with only use the melting polymkeric substance of hydroxyl or the thermostability of the polyacetal that melting oligopolymer stablizer is stable.

The invention further relates to the not molten polymer stable polyacetal composition that thermostability has been improved.Particularly relate to and use 0.05-3.0%(weight) not molten polymer stablizer (being described in down) and 0.02-1.0%(weight) the stable polyacetal composition of phenol type antioxidant of at least a amide containing, above-mentioned weight percentage is based on polyacetal, the weight of the phenol type antioxidant of molten polymer stablizer and amide containing not.Another kind of alternative be wherein to comprise 0.05-3.0%(weight) molten polymer stablizer not, 0.02-1.0%(weight) at least a primary antioxidant and 0.01-1.00%(weight) at least a melting co-stabilizer compound, can improve the thermostability with the stable polyacetal composition of this not molten polymer, above-mentioned weight percentage is based on polyacetal, not molten polymer stablizer, oxidation inhibitor and melting co-stabilizer compound.

The molten polymer stablizer does not contain formaldehyde activity hydroxy and/or formaldehyde reactive nitrogen base, and the number average particle size in polyacetal is a non-melt less than 10 microns, and it is used to increase the melt-processed stability of polyacetal.The melting co-stabilizer compound that uses in the stable polyacetal composition of this not molten polymer is selected from the melting thermo-stabilizer of known polyacetal.Oxidation inhibitor comprises the phenol type antioxidant of primary antioxidant and amide containing, and the both is that prior art is known.Use melting co-stabilizer and oxidation inhibitor do not increase the stability in the course of processing, but increase long-term exposure in airborne stability.In polyacetal composition, in the presence of the phenol type antioxidant of amide containing, perhaps in the presence of melting co-stabilizer compound and primary antioxidant, cause the permanent stability of polyacetal composition and aerobic stability thereof obviously to improve.

The present invention relates to the improvement and the not improvement of the stability of the stable polyacetal composition of molten polymer of the stability of the stable polyacetal composition of Mierocrystalline cellulose.

I. the polyacetal composition that Mierocrystalline cellulose is stable

Have now found that the stable polyacetal composition of mixed stabilizer system with micro-crystallization or fibrous cellulose and at least a co-stabilizer compound has improved thermostability (disengaged by less formaldehyde and record).Have found that the mixed stabilizer system of being made up of micro-crystallization or fibrous cellulose and at least a co-stabilizer compound does not resemble easy degraded the common nylon stabilizer, described micro-crystallization and fibrous cellulose are fused not under the melt processing temperature of polyacetal.And, on average be better than only using the thermostability (by hot release formaldehyde test determination) of the stable polyacetal composition of one-component in the stabiliser system of the present invention with the thermostability of the stable polyacetal composition of cellulose mixture based stabilizer system of the present invention.

In order to reach above-mentioned improvement, it is less to be that formaldehyde disengages, Mierocrystalline cellulose stable composition of the present invention is mainly by following (a), (b) and (c) form, wherein, (a) be 0.05-5%(weight) micro-crystallization or fibrous cellulose stablizer, (b) for 0.05-4%(weight) be selected from co-stabilizer at least a in the polymkeric substance of polyamide-based co-stabilizer and fusible hydroxyl or the oligopolymer co-stabilizer and (c) 91.0-99.9%(weight) polyacetal.Mierocrystalline cellulose stable composition of the present invention preferably is mainly by 0.05-2%(weight) component (a) cellulose stabiliser, 0.05-2%(weight) component (b) co-stabilizer compound and 96.0-99.9%(weight) component (c) polyacetal composition.Best Mierocrystalline cellulose stable composition of the present invention is mainly by 0.05-1%(weight) component (a) cellulose stabiliser, 0.05-1%(weight) component (b) co-stabilizer compound and 98.0-99.9%(weight) component (c) polyacetal composition.Above-mentioned all percentage number averages are with component (a), (b) and gross weight (c) be basic.If use more than a kind of co-stabilizer compound in Mierocrystalline cellulose stable composition of the present invention, the overall weight percent of co-stabilizer compound should be in the disclosed scope of said components (b) in the Mierocrystalline cellulose stable composition.

I (a). component (c): polyacetal

Term " polyacetal " comprises the homopolymer (its end group is by esterification or etherified sealed end) of the cyclic oligomer of formaldehyde homopolymer or formaldehyde and cyclic oligomer and other monomeric multipolymer of formaldehyde and formaldehyde as used herein, these monomers have two adjacent carbonss at least in main chain can produce alkylidene oxide, the multipolymer end group can be hydroxy-end capped, also can be by esterification or etherified sealed end.

The polyacetal that uses in the present composition be side chain or straight chain, general number-average molecular weight scope is 10,000-100,000, preferably 20,000-70,000.Usually with gel permeation chromatography molecular weight (in meta-cresol, under 160 ℃, using the Du Pont PMS bimodal column annex of nominal porosity 60A and 1000A).According to required physicals and processing characteristics, though can use the higher and lower polyacetal of molecular-weight average, but the molecular-weight average of the above-mentioned polyacetal of mentioning is preferred, like this can be in the pressing that this composition makes, the optimum balance that provides the well blend of the each component of melting mixing in the said composition to combine with the various physicalies that need most.

As mentioned above, polyacetal can be homopolymer, multipolymer or their mixture.Multipolymer can contain one or more comonomers, for example is generally used for preparing those monomers of polyacetal composition.More general comonomer comprises the ring-type adducts of the oxyalkylene of 2-12 carbon atom and they and formaldehyde.The amount of comonomer is not more than 20%(weight), be preferably and be not more than 15%(weight), most preferably about 2%(weight).Most preferred comonomer is an oxyethane.General polyacetal homopolymer is better than multipolymer, because its hardness is bigger.Preferred polyacetal homopolymer comprises that its terminal hydroxyl by chemical reaction, forms ester group or ether respectively, is preferably formed as acetate groups or methoxyl group and end capped those homopolymer.

I (b). component (a) and (b): cellulose base stabiliser system

The stabiliser system that uses in the Mierocrystalline cellulose stable composition of the present invention is formed by component (a) with (b), wherein component (a) is micro-crystallization or fibrous cellulose, and component (b) is for being selected from a kind of at least in polyamide-based co-stabilizer and some fusible hydroxyl polymer-containing and the oligopolymer co-stabilizer.

I (b) is (ⅰ). component (a): micro-crystallization and fibrous cellulose

Component (a) cellulose stabiliser can be avicel cellulose or fibrous cellulose.Avicel cellulose is preferred.Micro-crystallization and fibrous cellulose both be by naturally occurring cellulose-derived, and be fused not under the polyacetal melt processing temperature.

Avicel cellulose is that prior art is known, and is commercial on sale.3023104(is for reference at United States Patent (USP)) in have a detailed description, be referred to herein as " Mierocrystalline cellulose crystalline aggregate ".At Industrial and Engineering Chemistry, 42 volumes 502-507(1950), are also described avicel cellulose in detail in " Hydrolysis and Crystallization of Cellulose " literary composition.

Consistent with United States Patent (USP) 3023104 described contents, the avicel cellulose that uses in the Mierocrystalline cellulose stable composition of the present invention can obtain from commercial, perhaps can be by Mierocrystalline cellulose acidolysis preparation.In both cases, avicel cellulose all should satisfy purity requirement described below.In the Mierocrystalline cellulose acidolysis, any pars amorpha of the plain chain of acid dissolving protofibril.From this acidolysis process remain do not dissolve the part be a kind of granular, non-fibrous or crystallized form, described form is the crystallization shape and the continuous splitted result of the fine structure between the pars amorpha of protofibril element.Known be crystallization shape do not dissolve the part under the melt processing temperature of polyacetal, be infusible.The melt processing temperature of polyacetal is no more than 280 ℃ usually.For a person skilled in the art, the method for preparing avicel cellulose with the Mierocrystalline cellulose acidolysis is known, for example at United States Patent (USP) 3,023, has described this method among 104 the 2nd hurdles and the embodiment.

The avicel cellulose that uses in the Mierocrystalline cellulose stable composition of the present invention has certain " leveling degree " (level-off degree) of polyreaction.At United States Patent (USP) 3,023, narrated the leveling degree of polyreaction in 104.In more detail, this patent has been described a such point, and the Mierocrystalline cellulose that carries out acidolysis at this some place is after after a while, and it is constant that its molecular weight reaches substantially.In other words, can indicate the anhydrous grape sugar unit that forms cellulose materials sometimes at this point place repeating unit or monomeric number and become considerably constant.Obviously in the degree of being of the polyreaction of this point place material " leveling ", thereby " the leveling degree " of called after polyreaction.

With United States Patent (USP) 3,023,104 described contents are consistent, and the preferred average polymerization reaction of the avicel cellulose that uses in Mierocrystalline cellulose stable composition leveling degree is 125-375 anhydrous grape sugar unit.In theory, all materials should have this identical polymerization degree in this scope, but this is very difficult, if can not reach, the actual polymerization degree that is preferably at least 85% material is not less than 50 and be not more than 550.Be more preferably average polymerization leveling degree in the 125-375 scope, the actual polymerization degree of at least 90% material is in the 75-500 scope, and more preferably the actual polymerization degree of at least 95% material is in the 75-450 scope.The preferred average polymerization leveling degree of avicel cellulose is 200-300 as used herein, and wherein the actual polymerization degree of at least 90% material is in the 75-550 scope.The most preferred average polymerization leveling degree of avicel cellulose is 175-225 as used herein.

United States Patent (USP) 3,023,104 point out, general avicel cellulose average particle size is 300 microns.Be the present invention's purpose, mean particle size is answered on point of sd so, makes that wherein 50% particle is less than this mean value, and 50% particle is greater than this mean value.Can use measured by standard techniques average particle size, for example microscopy, gravity settling, size analysis and electron microscope.The preferred method of measuring granularity is a settling methods.

Have found that for the Mierocrystalline cellulose stable composition, stability reduces and increases with the avicel cellulose mean particle size.Though therefore the average particle size of micro-crystallization is about 300 microns, but the average particle size of avicel cellulose is preferably 100 microns or littler as used herein, be more preferably 50 microns or littler, good again is 25 microns or littler, most preferably 10 microns or littler.

Fibrous cellulose is that prior art is known and be commercial on sale.Available concerning ordinary skill, the technology that obtains easily is from naturally occurring preparation of cellulose fibrous cellulose.For example, the method for available spraying wood pulp prepares fibrous cellulose, carries out purifying then, makes it satisfy purity requirement described below.Another is with crude substance, and the example of existence is a cotton fibre.General fibrous cellulose exists with the flat belt-like form.Reach this illustrational as a result the time width and the thickness of the flat band of these fibrous celluloses be not crucial.But, in general, about 25 microns of the width average of these flat bands, mean thickness is 6 microns.Reaching in this illustrational result, what the length of the flat band of fibrous cellulose neither be crucial.The length of commercial available fibrous cellulose surpasses average fiber length, from below 300 microns to less than 22 microns.Though average fiber length is not crucial, because can causing fibrous cellulose stablizer surface-area, the average fiber length minimizing increases, therefore stable improving along with the minimizing of average fiber length is desired.

Another kind of naturally occurring fibrous cellulose can make by the standard fermentation method from generating cellulosic bacterium (as acetyl bacterium and glyconic acid bacterium).The cell of bacterium is destroyed with hot alkali treatment in the fermentation back, and isolates bacteria cellulose fibre by a series of washings and dehydrating step.The bacteria cellulose fibre that obtains can exist with the crosslinking net of complexity or with distinct fibers form.The representational thickness of these bacteria cellulose fibres is about 0.1 micron.

Importantly avicel cellulose that uses in the Mierocrystalline cellulose stable composition and fibrous cellulose do not have basically and make the Derlin unstable compounds.The unstable impurity that may exist in commercially available micro-crystallization that uses in the present composition and the fibrous cellulose can be chemically examined with following method: (1) 1-10%(weight) pH value of micro-crystallization or fibrous cellulose aqeous suspension, (2) the non-volatile the ash content of coal of micro-crystallization or fibrous cellulose, and/or the heavy metal content of (3) micro-crystallization or fibrous cellulose.

More particularly, we advise the 1-10%(weight that the present composition uses) optimum PH value range of micro-crystallization or fibrous cellulose aqeous suspension is 5.5-7 and be 5.5-8 for Copolyacetal for polyacetal homopolymer.For homopolymer and multipolymer polyacetal, the PH scope of preferred this aqeous suspension is 5.5-7.We advise that the non-volatile ash oontent (ash content that obtains) of avicel cellulose or fibrous cellulose less than 0.25%, is more preferably less than 0.10% more than or equal to 800 ℃ the time, preferably less than 0.02%.We advise that also the heavy metal content of avicel cellulose and fibrous cellulose is less than 10ppm.In order to obtain maximum heat stability, we advise the non-volatile ash oontent of avicel cellulose and fibrous cellulose and heavy metal content are reduced to minimum usually.

I (b) is (ⅱ). component (b): co-stabilizer compound

The term that uses in the Mierocrystalline cellulose stable composition " co-stabilizer compound " is meant the compound of the co-stabilizer of the fusible polymkeric substance that is selected from polyamide-based co-stabilizer and some hydroxyl or fusible oligopolymer." fusible " is meant the fusing point of the polymkeric substance of hydroxyl or oligopolymer or the second-order transition temperature melt processing temperature less than polyacetal, perhaps, be meant that the melt-flow speed of described co-stabilizer is greater than 1/10th of this polyacetal velocity of flow under the melt processing temperature of polyacetal.Fusing point and second-order transition temperature available standards dsc analysis technical measurement, melt-flow speed can be used technical measurement known in the state of the art, for example ASTM-D1238.Adoptable technology will not narrated in fused polymer stabilizer one joint below.Component (b) co-stabilizer compound can be a kind of co-stabilizer compound, also can be multiple co-stabilizer compound.

The polyamide-based co-stabilizer that is used for the Mierocrystalline cellulose stable composition is that prior art is known, and knows that further it is the thermo-stabilizer of polyacetal.Under the melt processing temperature of polyacetal, the polyamide-based stablizer can be fusible, also can be fused not.Such polymeric amide co-stabilizer compound is commercial available, and those skilled in the art can prepare with easy-to-use technology.

Described the specific polyamide-based co-stabilizer that uses in the present composition in several pieces of United States Patent (USP)s, these patents comprise people's such as Alsup U.S.P.2993025 and the U.S.P.4 of Johnson, 098,843, list for reference at this.Preferred polyamide-based co-stabilizer is to be dispersed in nylon 66(in the vector resin such as the U.S.P.4 of Johnson in advance, described in 098,843).Another kind of preferred polyamide-based co-stabilizer is respectively a nylon 66,33/23/43 ter-polymers of nylon 6/10 and nylon 6.Also having a kind of preferred polyamide-based co-stabilizer is to be dispersed in nylon 66 in the vector resin (for example thermoplastic polyurethane vector resin) and 85/15 multipolymer of nylon 6 in advance.Above such polyamide copolymer at the U.S.P.4 of Wagman, made detailed description in 640,949, list for reference at this.

Some the fusible polymkeric substance or the fusible oligopolymer co-stabilizer that are used for the hydroxyl of Mierocrystalline cellulose stable composition are that prior art is known, and at U.S.P4, are described in 766,168 and U.S.P.4,814,397, list for reference at this.

U.S.P.4,766, the melting polymkeric substance of 168 described hydroxyls or melting oligopolymer co-stabilizer are the polymkeric substance or the oligopolymers of following a kind of hydroxyl, and wherein, the atom in the main chain that hydroxyl directly or indirectly links to each other with it is not more than 20 chain atoms and separates mutually.Be preferably, the melting polymkeric substance of hydroxyl or melting oligopolymer co-stabilizer compound are the polymkeric substance or the oligopolymers of following a kind of hydroxyl, promptly average per 20 carbon atoms contain a hydroxyl at least in polymkeric substance or oligopolymer main chain, and each carbon atom contains a no more than hydroxyl in the main chain.Be more preferably that the ratio of carbonatoms is 1 in the main chain: 2-1: 10, preferably 1: 2-1: 5.The melting polymkeric substance co-stabilizer of good especially hydroxyl comprises poly-(vinyl alcohol), poly-(ethylidene vinyl alcohol), the hydroxy ester of poly-(methyl) acrylate, as poly-(Rocryl 410) or poly-(hydroxyethyl methylacrylate), and vinyl alcohol/methylmethacrylate copolymer.Preferred hydroxyl melting polymkeric substance co-stabilizer is poly-(ethylidene vinyl alcohol).

The melting polymkeric substance of the hydroxyl described in the U.S.P4814397 or melting oligopolymer co-stabilizer are hydroxyl and at least one another kind of functional group's polymkeric substance or oligopolymers, this another kind functional group is the Lewis base stronger than hydroxyl, and hydroxyl polymkeric substance or the atom in the oligopolymer main chain indirect with it or that directly link to each other are on average separated by no more than 20 chain atoms.Other functional groups' example comprises amides, amine, ureas and amino formate.Amides and amine are preferred, and amides is most preferred.The example of the melting co-stabilizer of particularly preferred hydroxyl comprises the multipolymer of Rocryl 410 and acrylamide, Methacrylamide, dimethylaminoethyl methacrylate or vinyl 2-Pyrrolidone.

I (c). the recommendation purity of each component

Micro-crystallization that uses in the Mierocrystalline cellulose stable composition or fibrous cellulose and co-stabilizer compound are substantially free of and make the Derlin unstable compounds, and this is very important.The heavy metal content of micro-crystallization and fibrous cellulose, ash content and PH scope are described in detail in the above.Describe the purity of other recommendations below in detail.

At stable ester in the end capped or end capped polyacetal homopolymer of part ester, we advise that micro-crystallization and fibrous cellulose and co-stabilizer are substantially free of makes the unsettled alkaline matter of polyacetal, as metal, aqua ammonia, sodium acetate and other basic metal or alkaline-earth metal acetate.Preferably should remove the alkaline impurities in micro-crystallization and the fibrous cellulose, its content should be not more than 200ppm, preferably is not more than 10ppm; Simultaneously, preferably should remove the alkaline impurities in the co-stabilizer, make its content be not more than 50ppm, preferably be not more than 10ppm.Stable all be that the higher concentration alkaline matter in micro-crystallization and fibrous cellulose and the co-stabilizer is allowed in the ether capped Copolyacetal or homopolymer basically.In addition, if the impurity in micro-crystallization and/or fibrous cellulose or the co-stabilizer only is weak base, can allow quite high content, this is self-evident.

In stable polyacetal homopolymer and multipolymer, when using micro-crystallization and fibrous cellulose and co-stabilizer, we advise that the acidic impurities in micro-crystallization and fibrous cellulose and the co-stabilizer should reduce to minimum.For micro-crystallization and fibrous cellulose, preferably should remove acidic impurities, make its content be not more than 250ppm, preferably be not more than 10ppm; Simultaneously, preferably should remove these impurity in the co-stabilizer, make its content be not more than 50ppm, preferably be not more than 10ppm.When containing alkaline impurities,, the impurity in micro-crystallization and/or fibrous cellulose or the co-stabilizer allows also that this should be self-evident if only being weakly acidic, quite high content.

Therefore, in micro-crystallization and/or fibrous cellulose and/or co-stabilizer, there are these acidity and/or alkaline impurities, and when its content is big must be enough to make the stable polyacetal composition of Mierocrystalline cellulose unstable the time, so, before it being joined in the Mierocrystalline cellulose stable composition, should purifying micro-crystallization and/or fibrous cellulose and/or co-stabilizer.Volatile impunty vacuum available baking oven in micro-crystallization and/or fibrous cellulose and/or the co-stabilizer is removed.Non-volatile impurities wherein can be purified with suitable liquid (for example water) washing.

I (d). other component

The polyacetal composition that Mierocrystalline cellulose of the present invention is stable, except containing polyacetal, beyond micro-crystallization or fibrous cellulose and at least a co-stabilizer compound, self-evident ground also can comprise other various compositions, properties-correcting agent and additive general in the polyacetal mold resin, comprise said those co-stabilizers in addition, antioxidant, pigment, tinting material, toughner, toughener, UV stablizer, sterically hindered amine stabilizer, nucleator, lubricant, glass fibre, silicone oil, polytetrafluorethylepowder powder or fiber and filler.Some pigment and tinting material itself plays opposite effect to the stability of polyacetal composition, and this point also is self-evident.

II. the stable polyacetal composition of molten polymer not

The present invention relates to further improve permanent stability with the stable polyacetal composition of molten polymer stablizer not for the purpose of melt-processed, this is by the phenol type antioxidant that adds amide containing therein or by adding primary antioxidant therein simultaneously and fusible co-stabilizer compound reaches.

II (a). improve by molten polymer stable composition not with the phenol type antioxidant of amide containing

Have found that containing not, the polyacetal composition of molten polymer stablizer has good processing stabilizers.Yet, being exposed in the air and surpassing the regular hour, the physical properties of described composition will suffer a loss.Because these compositions have excellent processing stability, in commercial applications, very thirst for using these compositions.Therefore,, also wish to improve its permanent stability, perhaps keep its various physicalies for a long time for these stable polyacetal compositions of molten polymer not.

Have found that special oxidation inhibitor can improve significantly and contains the not permanent stability of the polyacetal composition of molten polymer stablizer, this point can be confirmed with its physical properties of long-term maintenance.It should be noted that when known oxidation inhibitor can increase many compositions stable they always are not easy to transfer to another kind of composition from a kind of composition, this point is very important.The effect of oxidation inhibitor is decided by various variable factors, for example, and specific base polymer and specific stablizer in the composition.And, produce interaction in oxidation inhibitor and stablizer or the composition between other component, limited the effect of oxidation inhibitor, perhaps make composition have unacceptable performance.

Specifically, the most effective oxidation inhibitor that has found that the permanent stability of improving the polyacetal composition contain at least a not molten polymer stablizer is the phenol type antioxidant of amide containing.When the stable polyacetal composition of molten polymer does not contain the phenol type antioxidant of at least a amide containing, situation when being the phenolic aldehyde oxidation inhibitor of not amide containing with the oxidation inhibitor that does not contain oxidation inhibitor or adding is compared, and said composition is bigger and keep its whole physicalies more significantly.

The not molten polymer stable composition of improving with the phenol type antioxidant of amide containing, main by following (a), (b) and (c) form), wherein (a) is 0.05-3.0%(weight) at least a not molten polymer stablizer, (b) be 0.02-1.0%(weight) phenol type antioxidant of at least a amide containing and (c) 96.0-99.93%(weight) polyacetal.Unless otherwise indicated, disclosed all wt percentage ratio all is based on polyacetal, the weight of the phenol type antioxidant of molten polymer stablizer and amide containing not in this section.Said composition preferably contains 0.15-1.5%(weight), 0.2-1.0%(weight more preferably) component (a) molten polymer stablizer not.The preferred content of the phenol type antioxidant of amide containing is 0.02-0.5%(weight), best is 0.05-0.25%(weight).The phenol type antioxidant of amide containing can not be added in the said composition yet, its content is the 0.05-0.50%(weight of composition), be preferably 0.05-0.25%(weight), 0.10-0.20%(weight preferably), described weight percentage is based on polyacetal, the weight of molten polymer stablizer and all types oxidation inhibitor not.

Also further find, contain the permanent stability of the polyacetal composition of fusible polymer stablizer not can in said composition, add at least a primary antioxidant and at least a a small amount of the fusile polyacetal co-stabilizer and improve.

II (a) is (ⅰ). component (c): polyacetal

The component (c) that is used in the stable polyacetal composition of the not component of molten polymer stable composition (c) polyacetal polymer and Mierocrystalline cellulose recited above is identical.

II (a) is (ⅱ). component (a): fused polymer stabilizer not

Not molten polymer stablizer used herein is homopolymer or the multipolymer that contains formaldehyde reactive nitrogen base, formaldehyde activity hydroxy or formaldehyde reactive nitrogen base and formaldehyde activity hydroxy." formaldehyde activity " is meant that hydroxyl contains an oxygen and is bonded to a top hydrogen atom, and the nitrogen base contains a nitrogen and is bonded to one or two top hydrogen atom.Formaldehyde will with molten polymer stablizer not-OH or-reaction of NH key.These active sites are called the formaldehyde active site at this.Preferred not molten polymer stablizer is formaldehyde reactive nitrogen base or the hydroxyl that contains maximum formaldehyde active sites.For example, contain the formaldehyde reactive nitrogen base, wherein have directly link to each other the not molten polymer stablizer of (promptly this group has two formaldehyde active sites) of two hydrogen atoms to be better than having only the hydrogen atom stablizer that contains the formaldehyde reactive nitrogen base of (promptly this group has a formaldehyde active site) that directly links to each other with nitrogen-atoms with nitrogen-atoms.

The molten polymer stablizer does not have ten repeating units at least.Weight-average molecular weight is better greater than 5000, preferably greater than 10000.The agent of weight-average molecular weight higher stable is preferred, and this in addition higher weight-average molecular weight is favourable to reducing formation mould settling.

The molten polymer stablizer is not fused not under the polyacetal melt processing temperature.So-called " not fusion " is meant that " the main fusing point " of molten polymer not is higher than the melt processing temperature of polyacetal, so it keeps solid state basically in polyacetal melt-processed process.Have again, if " the main fusing point " of molten polymer stablizer is not lower than the melt processing temperature of polyacetal, but under this temperature unconspicuous melt-flow, then this not the molten polymer stablizer remain " not fused ".Because molten polymer viscosity is very not high, for example have high molecular or high-crosslinking-degree, so its melt-flow speed is not obvious.

Be lower than at " the main fusing point " of molten polymer stablizer not under the situation of melt processing temperature of polyacetal, its melt-flow speed can be measured by the ASTM-D1238 standard method, preferably less than 1/10th of polyacetal melt-flow speed." the main fusing point " of molten polymer available differential scanning calorimeter is not measured." main fusing point " is a such temperature, the heat maximum that absorbs of molten polymer not under this temperature, and promptly polymer stabilizer shows maximum absorption heat under this temperature.As example how to measure melt-flow speed, according to ASTM-D1238, melt-flow speed should be measured under 200 ℃ and 2.16 kilograms of loads.Before measuring melt-flow speed, the molten polymer stablizer should be about 12 hours of 90 ℃ of dryings.Then, molten polymer stablizer not is added in the melt indexer of application of load of jam-pack, and at six minutes internal heating to test temperature, remove unstopper then.In three minute timed interval, measured melt flow index.Below about the preparation method of molten polymer stablizer not openly after, melt-flow velocity determination technology will further be discussed.

The for example available DUPONT 9900 type differential scanning calorimeters (DSC) of the main fusing point of molten polymer stablizer are not measured in nitrogen atmosphere.In order to reduce a small amount of moisture or the issuable influence of solvent, with each not molten polymer stablizer sample at first be heated to about 140 ℃ and kept 10 minutes.This sample is cooled to about 25 ℃ then, is heated to about 350 ℃ with about 20 ℃/minute speed again.In above-mentioned specific DSC, with the temperature that provides when producing heat absorption.The heat that absorbs is represented with joule/gram, obtains each heat that absorbs respectively.Main fusing point absorbs that maximum temperature of heat (joule/gram) exactly.

Polyacetal carries out melt-processed usually under the about 170-260 of melt temperature ℃, be 185-240 ℃ preferably, preferably 200-230 ℃.The molten polymer stablizer is not fused not under the specified temp of polyacetal melt-processed.

The molten polymer stablizer is not after with the polyacetal melt-processed, and its number average particle size is less than 10 microns.Before with the polyacetal melt-processed, its number average particle size also should be less than 10 microns.Obviously, (for example in drying process) can produce very loose not molten polymer stablizer agglomerate granule in the preparation and sepn process of molten polymer stablizer not.In order to measure number average particle size exactly, for the not molten polymer stablizer that contains very loose agglomerate, before mensuration, loose agglomerate should be pulverized before melt-processed, if not, and can be discounted in mensuration.No matter whether the molten polymer stablizer does not contain very loose agglomerate, can both measure with the transmission electron microscope standard technique.The details of measuring number average particle size before and after melt-processed will be introduced hereinafter.

Use suitable hydroxyl monomer, the hydroxy alkyl ester of acrylic or methacrylic acid for example can be incorporated into the formaldehyde activity hydroxy not in the molten polymer stablizer.Another kind alternatively is transformed into hydroxyl to another kind of group, for example by the hydrolysis of ester or epoxide, perhaps by the reduction of carbonyl, can not produce the formaldehyde activity hydroxy on the molten polymer stablizer.No matter how this method to introduce the formaldehyde activity hydroxy, the not molten polymer stablizer that makes thus must be fused not under the polyacetal melt processing temperature, perhaps can make not fused.

Equally, use suitable nitrogen containing monomer, for example acrylamide and Methacrylamide can be introduced the formaldehyde reactive nitrogen base not in the molten polymer stablizer.Preferred nitrogen containing monomer is the monomer that those results can generate the polymer stabilizer that contains formaldehyde reactive nitrogen base (two hydrogen atoms that are connected with nitrogen are wherein arranged).Particularly preferred monomer is an acrylamide, and it generates following polymer stabilizer when polymerization, and promptly its all formaldehyde reactive nitrogen bases basically directly link to each other with polymkeric substance as the side chain of polymer backbone, perhaps link to each other with polymkeric substance indirectly as polymer lateral chain.Also can not produce the formaldehyde reactive nitrogen base on the molten polymer stablizer in addition by the modification of polymkeric substance or multipolymer.Using and only making resulting polymers is fused method not under the polyacetal melt processing temperature, perhaps can make the not method of fused polymkeric substance, all can introduce the formaldehyde reactive nitrogen base.

The amount of formaldehyde activity hydroxy or active nitrogen base must not be to make the atom that directly or indirectly links to each other with the formaldehyde active group in the main chain be spaced from each other (promptly interconnecting) by no more than 20 chain atoms in the molten polymer stablizer.Be preferably not that per 20 carbon atoms contain at least one formaldehyde activity hydroxy or active nitrogen base in the molten polymer stablizer main chain.The ratio of carbonatoms is 1 in best is formaldehyde activity hydroxy or nitrogen base and the main chain: 2-1: 10, preferably 1: 2-1: 5.

Have again, the formaldehyde reactive nitrogen base should be present in not in the molten polymer stablizer in this wise, the feasible conduct not amount of the formaldehyde reactive nitrogen base of the part of the side chain of molten polymer stablizer skeleton or side chain is at least three times of amount of the formaldehyde active group (if any) that do not exist in the molten polymer stablizer main chain, preferably at least ten times.In other words, directly or indirectly the formaldehyde reactive nitrogen base that links to each other with atom in the molten polymer stablizer main chain not should be (if present) at least three times in the molten polymer stablizer main chain not, preferably at least ten times.The amount of the formaldehyde reactive nitrogen base that directly or indirectly links to each other with the side chain of polymer backbone is preferably widely greater than the amount (if present) of formaldehyde reactive nitrogen base in the main polymer chain.Preferably hundred-percent nearly formaldehyde reactive nitrogen base is connected on the side chain of polymer backbone.

The molten polymer stablizer can not be homopolymer or multipolymer, as long as it is a fused not.Preferably the molten polymer stablizer is not made by the radical polymerization polymerization by acrylamide or Methacrylamide, and the polymer stabilizer that makes thus is by 75%(mole at least) following unit forms:

R is hydrogen or methyl in the formula.Preferably by 90%(mole at least) said units forms, better by 95%(mole at least) said units forms, and preferably by 99%(mole at least) said units forms.

The molten polymer stablizer can not be the multipolymer that obtains by more than a kind of monomer polymerization.This comonomer can contain or not contain formaldehyde reactive nitrogen base and/or formaldehyde activity hydroxy.Other examples of monomers that can fusion comprises vinylbenzene, ethene, alkyl acrylate, alkyl methacrylate, N-vinyl pyrrolidone and vinyl cyanide.Multipolymer not molten polymer stablizer still must be a fused not.And the formaldehyde activity hydroxy and/or the nitrogen base (in required ratio) that must have desired number, and must have required number average particle size.Preferably should add comonomer, the mole number of formaldehyde active group in every gram polymer stabilizer is reduced within bounds.And should not reduce the number of formaldehyde active site in the polymer stabilizer excessively.

Particularly preferred multipolymer not molten polymer stablizer comprises Rocryl 410 and acrylamide, the multipolymer of Methacrylamide or dimethylaminoethyl acrylate methyl base amino-ethyl ester.

When the molten polymer stablizer did not contain a large amount of formaldehyde activity hydroxies (comparing with the quantity of formaldehyde reactive nitrogen base), perhaps when it only contained the formaldehyde activity hydroxy, it was favourable comprising other basic group in stablizer.This is because for the optimum performance as polyacetal stabilizer, and this stablizer should both react with formaldehyde and acid.These other groups are nitrogen-containing group preferably, for example amine, amides, ureas and amino formate.

The number average particle size of molten polymer stablizer must preferably less than 5 microns, preferably (not measured in the polyacetal first being processed less than 2 microns less than 10 microns.Except polymer stabilizer is not the fused, aspect the said processing stability that improves polyacetal, the number average granularity of molten polymer stablizer is not an important factor on reach.If the average particle size of polymer stabilizer is too big, then the interaction between polyacetal and the polymer stabilizer is very little, and the effect of polymer stabilizer can reduce greatly.Stability be with polyacetal and polymer stabilizer between the interaction that produces relevant, therefore require polyacetal and do not have good interaction between the molten polymer stablizer.The every gram not surface-area of molten polymer stablizer reaches maximum, will increase the interaction between polymer stabilizer and the polyacetal.The surface-area of every gram polymer stabilizer reduces and increases with its granularity.Therefore be starved of the little not molten polymer stablizer of granularity.

If molten polymer stablizer average particle size is not that then this stablizer plays stabilization to polyacetal in about 10-100 micron number order magnitude range, but may be reduced by the physical properties of articles that this polyacetal makes.In the goods that make with the polyacetal that contains the macrobead stablizer, sizable particle can make product surface inhomogeneous.Yet, wish to produce the goods of surface luster difference in some cases.In this case, the in fact preferential stablizer that uses more near the average particle size upper limit.

The not molten polymer stablizer that number average particle size is little can directly obtain in the polymerization process of monomer or comonomer.In order to obtain the little stablizer of average grain, can in organic medium, carry out polyreaction with common dispersion copolymerization method, perhaps in water medium, carry out polyreaction with ordinary emulsion polymerization method, these polymerization techniques all are that prior art is known.No matter be dispersion polymerization or letex polymerization, the not molten polymer stablizer that makes thus should be not dissolved in the polymerisation medium.Therefore, the selected polymerisation medium of polyreaction is decided by selected monomer or comonomer and resulting polymkeric substance.For example, when polymerization single polymerization monomer was acrylamide or Methacrylamide, preferred medium was a lower alkyl alcohol.Polyreaction can be addition polymerization polycondensation or radical polymerization.Most preferred method is the maximum method of number that makes formaldehyde active site in the formaldehyde active group.Usually, radical polymerization is preferred polymerization process.Preparing not from acrylamide, the most preferred method of molten polymer stablizer is a radical polymerization.No matter use which kind of method, polymerisation process must obtain the not molten polymer stablizer that contains formaldehyde reactive nitrogen base or formaldehyde activity hydroxy of predetermined amount.

Therefore in some cases, obtain short grained not molten polymer stablizer by polyreaction, it has enough main fusing points or enough low melt-flow speed, and it is a fused not when polymerization.In other cases, this polymer stabilizer is not fused not when polymerization, but before the polyacetal melt-processed or in the course of processing, owing to apply heat, it will produce crosslinked, reach sufficiently high molecular weight, like this, its melt-flow speed is low, is considered to not fused under the polyacetal melt processing temperature.Polymer stabilizer fused not when polymerization still becomes not fused after polymerization, this depends on the specific monomer that is aggregated or the character of comonomer.

In some cases, the polymer stabilizer that is made by monomer or comonomer polymerization is not fused not when polymerization, and does not become not fused in polyreaction subsequently.With after polyacetal mixes,, be easy to determine this point by fusing point or the melt-flow speed of measuring this stablizer.In this case, need comprise at least a in polymerization process or in the time afterwards can with the crosslinked monomer of polymer stabilizer.In polymerization process, produce crosslinked monomer and comprise polyfunctional unsaturated monomer, for example acrylate, methacrylic ester, acrylamide, methyl-prop enamine acyl and their derivative.Particularly preferred monomer is an Ethylene glycol dimethacrylate, N, N '-methylene-bisacrylamide and 1,4 butanediol diacrylate.After the polyreaction of polymer stabilizer is finished, can produce crosslinked monomer and comprise as glycidyl methacrylate vinylformic acid, methacrylic acid and their derivative.It is fused not under the polyacetal melt processing temperature that the amount of the cross-linking monomer that adds should be enough to make the polymer stabilizer that obtains.

Be with or without under the situation of cross-linking monomer, generating in the short grained polymerization process in organic medium, it is favourable having dispersion agent.Generate in the short grained polymerization process in emulsion, it is favourable having emulsifying agent.Dispersion agent and preparation method thereof is that prior art is known.At " Dispersion Polymerization in Organic Media " book (K.E.J.Barrett, New York:John Wiley ﹠amp; Sons, 1975) preparation and the system of selection of dispersion agent have been described.Particularly preferred dispersion agent comprises polyoxyethylene glycol and derivative thereof, methylmethacrylate copolymer and poly-(propylene oxide)-poly-(ethylene oxide) ethylene glycol segmented copolymer.Emulsifying agent and preparation method thereof also is that prior art is known.At " Emulsion Polymerization Theory and Practice " (D.C.Blackley, New York:John Wiley ﹠amp; Sons, 1975) in the book emulsion polymerization has been discussed.

Dispersion agent or dispersant solution or emulsifying agent and monomer and polymerisation medium, and also have comonomer and cross-linking monomer to join in the polymerization container simultaneously if you are using.When dispersion agent or dispersant solution or emulsifying agent are added in the stablizer, the polymer stabilizer that makes with following solvent wash, it is favourable removing dispersion agent or dispersant solution or emulsifying agent from polymer stabilizer, used solvent is soluble to dispersant solution or dispersion agent or emulsifying agent, but is insoluble to polymeric dispersant.If known road dispersion agent or dispersant solution or emulsifying agent make the polyacetal instability, it is correct especially doing so like this.Do not make the polyacetal instability if know dispersion agent or dispersant solution or emulsifying agent, they are stayed may be favourable in the polymer stabilizer, because they can reduce issuable particle aggregation effect in the polymer stabilizer drying process.

In addition, about the mensuration of melt-flow speed, people know that water and other liquid or lower molecular weight solid have remarkably influenced to melt-flow.Dispersion agent (when using) can be retained in the polymer stabilizer, and this is decided by the not technology of molten polymer stablizer of the separation of habitually practising.In order to obtain melt-flow speed accurately, before measuring melt-flow speed, to use following liquid scrubbing stablizer and remove dispersion agent, this liquid is solvent to dispersion agent, then is non-solvent to stablizer.After the washing, before measuring melt-flow speed, should be again with the stablizer drying.

After monomer or the comonomer polymerization, can obtain the little not molten polymer stablizer of number average granularity, and polymer stabilizer is still in polymerisation medium or in the solution.In this case, cross-linking monomer can be added in the polymer stabilizer in the polymerisation medium and obtain the little stablizer of number average granularity.After this polymer stabilizer becomes and is insoluble in the medium.Another kind method joins a kind of solvent of not dissolve polymer stablizer in the polymer stabilizer in polymerisation medium, can obtain the little stablizer of number average granularity.Equally, the polymer stabilizer in polymerisation medium can be joined in the solvent of dissolve polymer stablizer not.Currently known methods with other isolating polymer from polymerisation medium also can obtain the little stablizer of number average granularity.It is favourable using dispersion agent or emulsifying agent (as previously described those) separating stable agent polymkeric substance from polymerisation medium.

Any method can be used for preparing polymer stabilizer, as long as these methods can be produced short grained polymer stabilizer, before the polyacetal melt-processed, its number average granularity is less than 10 microns.And these small-particles should be fused not under the polyacetal melt processing temperature, should not condense or gather the sort of degree that is not easy to be dispersed in the polyacetal melts.

Before not molten polymer stablizer and polyacetal melt-processed, the available any method that can measure the number average granularity is measured its number average particle size.Preferable methods is to use Leeds ﹠amp; The MICROTRAC II SMALL PARTICLE ANALYZER(ANALYZER that NorthruP makes).In this way, polymer stabilizer is added to liquid for example in the 2-propyl alcohol, and uses hand shake, polymer stabilizer is dispersed in the liquid.Have under some situation, in the polymer stabilizer preparation process, may produce the loose aggregate of high density.In this case, need to mix more fully in order to smash loose aggregate." POLYTRON " (instrument of Brinckman) used the ANALYZER(analyser to provide the example of this well-mixed device to be) this dispersion liquid of molten polymer stablizer in liquid never, measure the number average granularity of this polymer stabilizer.

Concrete ANALYZER(analyser) example is 158705/158708 type, and it is equipped with 17 channel detector systems, can topped granular size scope 0.17-60 micron.This analyser prints the particulate percent by volume of diameter less than given detector channel.Calculate the number average granularity from this diameter and particle volume.In the calculating, the particle diameter of given detector channel and channel diameter are approximate.The granule number of each passage calculates with following formula:

N＝（10000V%）/（0.5236d ³/6）

N=gives the granule number of routing in the formula

V%=is at the particle volume of this passage

The d=channel diameter

To all 17 passage granule numbers summations, obtain the total particle number.The granule number of a passage be multiply by 100, and this result is divided by by the total particle number, obtains the particle percentage ratio of each passage.For the total percentage of calculated diameter less than that passage, from the passage of diameter minimum, diameter is less than or equal to the percentage ratio addition of all passages of that special modality, try to achieve cumulative percentage.From the cumulative percentage sum, number average particle size in the middle of trying to achieve.

With the polyacetal melt-processed after, the number average particle size of this stablizer should be preferably less than 5 microns less than 10 microns, preferably less than 2 microns.Any technology that can measure particulate number average granularity in the polymkeric substance all can be used to measure.The preferred method of measuring the number average granularity of the stablizer in the polyacetal is to use transmission electron microscope(TEM).

The following describes with the polyacetal melt-processed and after forming bead with it, how to measure the not number average granularity of molten polymer stablizer.With Reichert-Jung Ultracut E FC4E type diamond wafers slicing knife bead is cut into slices.Use standard-90 ℃ low temperature ultramicrotomy is cut into bead the thin slice of 90-120 millimicron.Taking out the section that still is positioned on the diamond blade also directly installs on copper transmission electron microscope(TEM) (TEM) grid.The section that installs is placed in the Denton D V-502 type vacuum-evaporator, is in high vacuum, uses the spectroscopically pure charcoal thin layer less than 20 millimicrons to be coated with stain.It is more stable when carbon coating makes the acetal section be exposed in the interior electron beam of transmission electron microscope(TEM).Use the carbon coating section of Zeiss EM10CR transmission electron microscope(TEM) check on the TEM grid then.At 70mm(Kodak 5302) magnification 1000X demarcated in record on the film, and the image of 2520X and 5000X also prints.Use commercially available diffraction replica grating to combine, obtain final image multiplication multiple 4640X, 11800X and 23000X with the 1 year calibration and photograph magnification of carrying out magnification that is as the criterion.From the image of record, measure at least 50 particulate diameters (comprising that macrobead reaches any particle of accumulative) with ruler, measure the number average granularity.The accumulative particle is handled as a particle.From at least 50 particulate mean value calculation number average granularities.

II (a) is (ⅲ). component (b): the phenol type antioxidant of amide containing

Component used herein (b) oxidation inhibitor be amide containing also be the phenol type.Acid amides can be primary, the second month in a season or teritary amide.Phenol is sterically hindered.Below these examples show that contain acid amides and phenol functional group's oxidation inhibitor simultaneously and compare with the phenol type antioxidant of amide containing not, the former gives and contains the not better permanent stability of polyacetal composition of molten polymer stablizer.

The phenol type antioxidant of amide containing is that prior art is known.The example of the phenol type antioxidant of amide containing comprises β-(3, the 5-di-tert-butyl-hydroxy phenyl) acid amides of propionic acid (but being not limited to these), for example, 1,3,5-three-(3,5-di-tert-butyl-hydroxy phenyl-propionyl)-six hydrogen-S-triazine, and N, N '-hexa-methylene-two (3,5-di-t-butyl-4-hydroxyl hydrocinnamamide).The phenolic aldehyde oxidation inhibitor of amide containing also comprises 2,2 '-the two ethyl-3-(3 of oxalyl diamino, the 5-di-tert-butyl-hydroxy phenyl) propionic ester.The phenol type antioxidant of preferred amide containing is N, N '-hexa-methylene two (3,5-di-t-butyl-4-hydroxyl hydrocinnamamide).

When the phenol type antioxidant Individual existence of amide containing or as the part of antioxidant mixture, existing, the permanent stability of the stable polyacetal composition of molten polymer are not improved.This mixture can be made up of the phenol type antioxidant of more than one amide containings, perhaps also can be made up of a kind of phenol type antioxidant of amide containing and a kind of oxidation inhibitor mixing of not amide containing.Under any circumstance in the polyacetal composition 0.02-1.0%(weight must be arranged) phenol type antioxidant of amide containing, described weight percentage is based on polyacetal, the weight of the phenol type antioxidant of molten polymer stablizer and amide containing not.

The oxidation inhibitor of amide containing is not primary antioxidant, i.e. chain termination, the oxidation inhibitor of amide containing functional group not.These oxidation inhibitor usually are called as the radical clean-out system.Most of primary antioxidants are sterically hindered phenol or secondary aromatic amine.The preferred not oxidation inhibitor of amide containing is the sterically hindered phenol type.

The sterically hindered phenol oxidation inhibitor of amide containing can not be added to the phenol type antioxidant of amide containing in the composition, the example of sterically hindered phenol oxidation inhibitor following (but being not limited to these):

Such as 2, the simple oxidation inhibitor of 6-dialkyl benzene phenols comprises 2,6-di-tert-butyl-4-methylphenol, 2-tertiary butyl-4,6-xylenol, 2,6-di-tert-butyl-4-methoxymethyl phenol and 2,6-two-octadecyl-4-methylphenol.

The derivative of alkylation quinhydrones, for example 2,5-di-tert-butyl-quinhydrones, 2,5-two tertiary amyl quinhydrones, 2,6-di-tert-butyl quinhydrones, 2,6-di-tert-butyl-4-hydroxyl-phenylmethylether, 3,5-di-tert-butyl-4-hydroxyl-phenylmethylether, 3,5-di-tert-butyl-4-hydroxy phenyl stearate, with two (3,5-di-tert-butyl-4-hydroxy phenyl) adipic acid ester.

Alkylidene bisphenols, for example, 2,2 '-methylene radical-two-(6-tertiary butyl-4-methylphenol), 2,2 '-methylene radical-two-(6-tertiary butyl-4-ethylphenol), 4,4 '-methylene radical-two-(6-tertiary butyl-4-methylphenol), 4,4 '-methylene radical-two-(2, the 6-t-butyl phenol), 2,6-di-tert-butyl-5-methyl-2-hydroxybenzyl)-the 4-methylphenol, 2,2 '-methylene radical-two-(4-methyl-6-(4-methylcyclohexyl)-phenol), 1, two (3, the 5-the dimethyl)-2-hydroxy phenyls of 1-)-butylene, 1,1-pair-(5-tertiary butyl-4-hydroxy-2-methyl phenyl)-butane, 2,2-two-(3,5-di-tert-butyl-4-hydroxy phenyl)-propane, 1,1,3-three-(5-tertiary butyl-4-hydroxyl-2-tolyl)-butane, 2,2 '-two-(5-tertiary butyl-4-hydroxyl-2-tolyl)-4-just-dodecyl sulfydryl butane, 1,1,5,5-tertiary butyl-4-hydroxyl-2-tolyl pentane, and ethylene glycol bis (3,3-two-(3 '-tertiary butyl-4 '-hydroxy phenyl)-butyl ester.

O-and N-benzyl compounds, for example, 3,3 ', 5,5 '-four tertiary butyls-4,4 '-dihydroxyl-dibenzyl ether and three-(3,5-di-tert-butyl-4-hydroxybenzyl)-amine.

The malonic ester of hydroxybenzylization, for example, two-octadecyl-2,2-pair-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonic ester, two-octadecyl-2-(3-tertiary butyl-4-hydroxy-5-methyl base benzyl)-malonic ester, two-octadecyl mercaptoethyl-2, two (3,5-di-tert-butyl-4-the hydroxybenzyl)-malonic esters of 2-and two-(4-(1,1,3,3-four-methyl butyl)-and phenyl)-2,2-pair-(3,5-di-tert-butyl-4-hydroxybenzyl)-malonic ester.

The hydroxybenzyl aromatic compound, for example, 1,3,5-three-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-Three methyl Benzene, 1,4-pair-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethyl--benzene and 2,4,6-three-(3,5-di-tert-butyl-4-hydroxybenzyl)-phenol.

The S-triaizine compounds, for example, 2,4,6-three-(3,5-di-tert-butyl-4-hydroxyphenoxy)-S-triazine, 2,4,6-three-(3,5-di-tert-butyl-4-leptodactyline)-S-triazine and 1,3,5-three-(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid ester.

The ester of β-(3,5-di-tert-butyl-4-hydroxy phenyl) propionic acid and monohydroxy-alcohol or polyvalent alcohol, for example, with methyl alcohol, ethanol, Stearyl alcohol, 1,6-hexylene glycol, 1,9-nonanediol, ethylene glycol, 1,2-propylene glycol, Diethylene Glycol, triethylene glycol, neopentyl glycol, tetramethylolmethane, the trimethylammonium hexylene glycol, trimethylolethane, the ester of triethylol propane and tris(2-hydroxy ethyl)isocyanurate.

The ester of β-(5-tertiary butyl-4-hydroxyl-3-tolyl) propionic acid and monohydroxy-alcohol or polyvalent alcohol, for example, with methyl alcohol, ethanol, Stearyl alcohol, 1,6-hexylene glycol, 1, the 9-nonanediol, ethylene glycol, 1, the 2-propylene glycol, Diethylene Glycol, triethylene glycol, neopentyl glycol, tetramethylolmethane, trimethyl cyclohexane glycol, trimethylolethane, the ester of TriMethylolPropane(TMP) and tris(2-hydroxy ethyl)isocyanurate.

3, the ester of 5-di-tert-butyl-4-hydroxyphenyl acetic acid and monohydroxy-alcohol or polyvalent alcohol, for example, with methyl alcohol, ethanol, Stearyl alcohol, 1, the 6-hexylene glycol, 1, the 9-nonanediol, ethylene glycol, 1, the 2-propylene glycol, Diethylene Glycol, neopentyl glycol, tetramethylolmethane, the trimethylammonium hexylene glycol, trimethylolethane, the ester of TriMethylolPropane(TMP) and tris(2-hydroxy ethyl)isocyanurate.

The example that can join the secondary aromatic amine oxidation inhibitor in the composition with the phenol type antioxidant of amide containing comprises following (but being not limited to these):

Diarylamine, for example, N-phenyl-a-naphthylamine, directed styrenated diphenylamine of P-and octylated diphenylamine.

The P-phenylenediamine, for example, N, N '-phenylbenzene-P-phenylenediamine and N, N '-two-betanaphthyl-P-phenylenediamine.

The preferred not oxidation inhibitor of amide containing be selected from triethylene glycol two (3-(3 '-tertiary butyl-4 '-hydroxyl-5 '-tolyl) propionic ester; Four (methylene radical (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane; Three (methylene radical (3,5-di-tert-butyl-4-hydroxy phenyl))-1,3, the 5-tricyanic acid; With 1-Stearyl alcohol (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate).

II (b). with the not molten polymer stable composition of fusible co-stabilizer compound and primary antioxidant improvement

The not molten polymer stable composition of improving with fusible co-stabilizer compound and primary antioxidant is mainly by following (a), (b), (c) and (d) form, wherein, (a) be 0.05-3.0%(weight) at least a not molten polymer stablizer, (b) be 0.01-1.0%(weight) at least a fusible co-stabilizer compound, (c) be 0.02-1.0%(weight) at least a primary antioxidant and (d) for 95-99.92%(weight) polyacetal.Preferred compositions is mainly by 0.15-1.5%(weight) at least a not molten polymer stablizer, 0.01-0.50%(weight) at least a fusible co-stabilizer compound, 0.02-0.50%(weight) at least a primary antioxidant and 97.5-99.8%(weight) polyacetal forms.Most preferred composition is mainly by 0.2-1.0%(weight) at least a not molten polymer stablizer, 0.05-0.30%(weight) at least a fusible co-stabilizer compound, 0.05-0.25%(weight) at least a primary antioxidant and 98.4-99.7%(weight) polyacetal forms.Above-mentioned all wt percentage ratio is with molten polymer stablizer not, melting co-stabilizer compound, and the weight of primary antioxidant and polyacetal is the basis.

II (b) is (ⅰ). component (d): polyacetal

Component (c) in the stable polyacetal composition of component used herein (d) polyacetal and top Mierocrystalline cellulose is identical.

II (b) is (ⅱ). component (a): molten polymer stablizer not

Component (a) not the component (a) described in the not molten polymer stable composition of molten polymer stablizer and top phenol type antioxidant modification with amide containing the molten polymer stablizer is not identical.

II (b) is (ⅲ). component (b): melting co-stabilizer compound

Being used for not, the component of molten polymer stable composition (b) " co-stabilizer " compound is the heat stabilizer compounds of any fusible polyacetal." melting " is meant the fusing point of co-stabilizer or the melt processing temperature that second-order transition temperature is lower than polyacetal, and the melt-flow speed that perhaps is meant co-stabilizer is greater than 1/10th of the velocity of flow of polyacetal under the polyacetal melt processing temperature.Fusing point and second-order transition temperature can be measured with foregoing dsc analysis.Melt-flow speed also can be measured with foregoing method.

The melting thermo-stabilizer of polyacetal is that prior art is known.The example of the melting thermo-stabilizer of these polyacetal comprises (but being not limited to these) polymeric amide, the compound of amide containing, carbamate, urea, the compound of ammoniated compound and hydroxyl.Should be noted that importantly strongly alkaline compound can make the polyacetal homopolymer instability, therefore, in being added to the polyacetal homopolymer composition before, these compounds all should be purified or its alkalescence is reduced to suitable degree.To further go through this problem below.

The polymeric amide stablizer is that prior art is known.Disclose polymeric amide as the purposes of polyacetal thermo-stabilizer and the preparation method of these polymeric amide in following patent, these patents are U.S.P.2,993,025, and U.S.P.2,966,467, U.S.P.3,001,966, U.S.P.3,235,624, U.S.P.3,288,885, U.S.P.3,103,499, U.S.P.4,744,934, U.S.P.3,960,984, U.S.P.4,098,843, and U.S.P.3,116,267.Preferred polymeric amide is that weight percent is respectively 33/23/43 nylon 66, the ter-polymers of nylon 6/10 and nylon 6.

The compound of amide containing is that prior art is known.The compound that discloses amide containing in the following patent is made the purposes of polyacetal thermo-stabilizer and the preparation method of these compounds, and these patents are U.S.P.3, and 574,786, U.S.P.3,592,873, U.S.P.3,355,514, U.S.P.3,787,353 and U.S.P.3,156,669.

Carbamate and urea are that prior art is known.They are open in following patent as purposes of polyacetal thermo-stabilizer and preparation method thereof: U.S.P.4,780,498, U.S.P.2,893,972 and U.S.P.3,144,431.

The compound that contains amine is that prior art is known.Following patent disclosure contain amine compound as the purposes of polyacetal thermo-stabilizer and the preparation method of described compound, these patents are U.S.P.3,133,896, U.S.P.2,920,059, U.S.P.2,376,354, U.S.P.2,810,708, U.S.P.4,751,272, U.S.P.3,406,222, U.S.P.3,249,582, U.S.P.3,448,169 and U.S.P.3,442,850.

The material of hydroxyl is that prior art is known.Following patent disclosure the purposes and preparation method thereof of these materials, list for reference at this: U.S.P.4,766,168, U.S.P.2,936,298, U.S.P.2,966,476, U.S.P.2,376,354, U.S.P.3,219,621, U.S.P.4,555,357, U.S.P.3,240,753 and U.S.P.3,459,789.Preferred hydroxy-containing compounds is at U.S.P.4, those disclosed in 766,168.Specifically, disclosed hydroxy-containing compounds is the polymkeric substance or the oligopolymer of hydroxyl among the U.S.P.4766168, wherein, the polymkeric substance or the atom in the oligopolymer main chain that directly or indirectly link to each other with hydroxyl on average are spaced from each other by no more than 20 chain atoms, and the polymkeric substance of hydroxyl or oligopolymer are essentially nonacid material.Disclosed concrete hydroxy-containing compounds comprises poly-(vinyl alcohol) among the U.S.P.4766168, poly-(ethylidene vinyl alcohol), the hydroxy ester of poly-(methyl) acrylate, as poly-(Rocryl 410), and vinyl alcohol/methylmethacrylate copolymer.To the preferred hydroxy-containing compounds of the present composition is poly-(ethylidene vinyl alcohol).

The melting co-stabilizer can be the mixture of simplification compound or multiple melting co-stabilizer.To the present invention not the stable preferred co-stabilizer of polyacetal composition of molten polymer be that weight percent is respectively 33/23/43 nylon 66, the trimer of nylon 6/10 and nylon 6, or at the hydroxyl polymer-containing described in the U.S.P.4766168.If co-stabilizer adds with mixture, so its preferably ratio of mixture be 1: 1-1: 5 following mixture, it is that weight percent is respectively 33/23/43 nylon 66, the trimer of nylon 6/10 and nylon 6 and the mixture of the hydroxyl polymer-containing described in the U.S.P.4766168.

II (b) is (ⅳ). component (c): primary antioxidant

Component (c) primary antioxidant and the melting co-stabilizer compound that use in molten polymer stable composition not are that prior art is known.Primary antioxidant is also referred to as chain termination oxidation inhibitor or radical scavenger in the prior art.Most of primary antioxidants are sterically hindered phenol or secondary aromatic amine.The preferred primary antioxidant that uses in the present composition is the sterically hindered phenol type.

The example (but being not limited to simple oxidation inhibitor) that belongs to the primary antioxidant of sterically hindered phenol oxidation inhibitor, the derivative that comprises the alkylation quinhydrones, alkylidene bisphenols, O-and N-benzyl compounds, the hydroxybenzyl malonic ester, the hydroxybenzyl aromatic compound, the S-triaizine compounds, the acid amides of β-(3,5-di-tert-butyl-4-hydroxy phenyl) propionic acid, β-(3,5-di-tert-butyl-4-hydroxy phenyl) ester of propionic acid and monohydroxy-alcohol or polyvalent alcohol, the ester and 3 of β-(5-tertiary butyl-4-hydroxy-3-methyl phenyl) propionic acid and monohydroxy-alcohol or polyvalent alcohol, the ester of 5-di-tert-butyl-4-hydroxyphenyl acetic acid and monohydroxy-alcohol or polyvalent alcohol.The object lesson of every kind of sterically hindered phenol oxidation inhibitor used herein be top II (a) (ⅲ) do not provided in the primary antioxidant of amide containing in saving those.

Preferred primary antioxidant is a sterically hindered phenol oxidation inhibitor, they are β-(3,5-di-tert-butyl-4-hydroxy phenyl) acid amides of propionic acid, for example, 1,3,5-three-3,5-di-tert-butyl-4-hydroxy phenyl propionyl)-and six hydrogen-S-triazine and N, N '-hexa-methylene-two-(3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide); 2,2 '-diacetyl two amido diethyl-3-(3,5-di-tert-butyl-4-hydroxy phenyl) propionic ester; Triethylene glycol two (3,3 '-tertiary butyl-4 '-hydroxyl-5 '-methyl (phenyl) propionic ester; With four (methylene radical (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane.Most preferred oxidation inhibitor is N, N '-hexa-methylene two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide).

The example that is primary antioxidant with secondary aromatic amine oxidation inhibitor comprises diarylamine and P-phenylenediamine, but is not limited to these.

Primary antioxidant can add with single a kind of primary antioxidant, also can add with the mixture of multiple primary antioxidant.This mixture preferably only is made up of sterically hindered phenol type primary antioxidant.No matter primary antioxidant is to add separately or add as mixture, the overall weight percent of primary antioxidant in polyacetal composition is necessary for 0.02-1.0%(weight), described weight percentage is with molten polymer stablizer not, primary antioxidant, and the weight of co-stabilizer and polyacetal is the basis.

II (c). molten polymer stable composition not:

Other component and recommendation purity

Obviously, not molten polymer stable composition described here can contain other component, properties-correcting agent and additive general in the polyacetal mold resin, comprises pigment, tinting material, the UV stablizer, photostabilizer, toughner, polytetrafluoroethylene fiber or powder, nucleator (as boron nitride and talcum), lubricant (as silicone oil and the hard esteramides of ethylene), and filler (as glass, carbon black and talcum).Some pigment, tinting material and other additive itself play opposite effect to the stability of polyacetal composition, and this also is self-evident.

Importantly, not molten polymer stablizer, melting co-stabilizer compound, oxidation inhibitor and any other component, properties-correcting agent or the additive that uses in the stable polyacetal composition of not molten polymer of the present invention do not make polyacetal resin unstable compounds or impurity basically.

When stable ester end-blocking or the end capped polyacetal homopolymer of part ester, each component that is added in the polyacetal should not make the unsettled alkaline matter of polyacetal basically.Preferably should remove alkaline impurities, make its content be not more than 50ppm, preferably be not more than 10ppm, when all being ether capped Copolyacetal or homopolymer basically, the alkaline matter of higher concentration allows stable.In addition, if the alkalescence of impurity quite a little less than, obviously high level is admissible.

In stable polyacetal homopolymer and two kinds of situations of multipolymer, it is minimum that the acidic impurities in each component of polyacetal composition should be reduced to.Preferably should remove acidic impurities, make its content be not more than 50ppm, preferably be not more than 10ppm.The same with the situation that contains alkaline impurities, if impurity only is weakly acidic, higher relatively obviously content can allow.

In any component in being added to polyacetal, must be enough to make the polyacetal composition instability if the amount of acidity and/or alkaline impurities is big, then in joining the present composition before, this component should be purified.For example, the not molten polymer stablizer that is used for the present composition can wash by liquid and purify.

III. the preparation method

Use the general strong mixing device of preparation thermoplastic polyacetal composite,, each component is mixed with polyacetal polymer, prepare composition of the present invention being higher than under the polyacetal component melting temperature.Used mixing device: rubber mill is for example arranged; such as interior mixing tanks such as " Banbury " and " Brabender "; have external heating type cavity or single blade or the interior mixing tank of multiple-blade by rubbing; " Ko-Kneaders " (kneader); multitube mixing machine (as " Farrel Continuous Mixers "); injector and forcing machine (single screw rod with twin screw, corotation change with the counting rotation).These devices can use separately, perhaps with static mixer, mix torpedo device and/or various other device, and as the valve that designs for this purpose, valve or screw rod are used in combination, to increase internal pressure and/or mixture strength.Forcing machine preferably.Certainly, mixing should be carried out under the temperature that is lower than polyacetal component generation obvious degradation.Usually, polyacetal composition carries out melt-processed between 170 ℃ to 280 ℃, is preferably between 185 ℃ to 240 ℃, preferably between 195 ℃ to 225 ℃.

With composition production moulded products of the present invention, can use any method in common, comprise compression moulding, injection molding, extrusion molding, blowing moulding, rotomoulding, melt-out spinning and hot-forming method.Injection molding preferably.The example of moulded products comprises sheet material, section bar, bar, film, silk, fiber, strapping, adhesive tape pipe and pipe.Aftertreatments such as these moulded products can be orientated, stretch, coating, thermal treatment, paint, lamination and plating.These moulded products and fragment thereof can grind and carry out mold pressing again and process.

The processing condition that prepare composition of the present invention and moulded products thereof comprise that melt temperature is about 170-280 ℃, are 185-240 ℃ preferably, preferably 200-230 ℃.When injection molding composition of the present invention, the complexity degree of being that the mould temperature is preferably as much as possible colder to make it the shape goods produced with desire adapts.General mould temperature is 10-120 ℃, and 10-100 ℃ better, and 50-90 ℃ is preferred.

Embodiment

In the following example, some comparative examples of the control test embodiment outside the specific embodiments of the invention and the scope of the invention are arranged.Can see that composition of the present invention is characterised in that and improve thermostability.Unless otherwise indicated, all umbers and percentage ratio all represents with weight, and all temperature are all used and degree centigrade represented.What the original measurement result represented for non-SI units has done conversion in suitable place.

I. each component of embodiment

A. polyacetal polymer component

The polyacetal polymer that uses among the embodiment is as follows below:

(a) polyacetal A-end capped homopolymer of acetic ester, about 40000 Hes of its number-average molecular weight

(b) polyacetal B-end capped homopolymer of acetic ester, its number-average molecular weight about 33000.

B. avicel cellulose stabilizer component

The avicel cellulose stablizer that uses among the embodiment below is as follows:

(a) " MC3 " commercially availablely grinds to form the about 3 microns avicel cellulose of mean particle size with air spray mill standard technique,

(b) " MC6 " is the about 6 microns avicel cellulose of commercial available mean particle size,

(c) " MC11 " commercially availablely grinds to form the about 11 microns avicel cellulose of mean particle size with air spray mill standard technique,

(d) " MC20 " is the about 20 microns avicel cellulose of commercial available mean particle size.

(e) " MC50 " be the about 50 microns avicel cellulose of commercial available mean particle size and

(f) " MC100 " is the about 100 microns avicel cellulose of commercial available mean particle size.

The polyreaction of the every kind of avicel cellulose that uses among the embodiment on average degree of leveling scope is 190-200.The heavy metal content of every kind of avicel cellulose that is used for embodiment is less than 10ppm, and its ash oontent is less than 0.05%, and the pH value scope of its 10% aqueous solution suspension is about 5.5-7.

C. fibrous cellulose stabilizer component

The fibrous cellulose stablizer that is used for embodiment is as follows:

" FC1 " is commercial available fibrous cellulose, about 300 microns of its average fiber length, and ash oontent is about 0.16%, and the pH value of its 5% aqeous suspension is 5.95.

" FC2 " is commercial available fibrous cellulose, and its average fiber length is less than 90 microns, ash oontent 0.15%, and the pH value of its 5% and 10% aqeous suspension is 5.2.

D. molten polymer stabilizer component not

The preparation that is used for the not molten polymer stablizer of embodiment is commented in following.

Mensuration from beginning adds initiator to reactor time to the time that polyreaction is finished and heat is emitted from reactor, be the total polymerization reaction times during this period of time.Use foregoing DU PONT 9900 types to carry out dsc measurement.Before melt-processed, measure the not granular size of molten polymer stablizer with foregoing ANALYZER.Employed here " PEG " is the polyoxyethylene glycol dispersion agent, and its molecular weight is about 8000.

Molten polymer stablizer A is not by 298.5 gram acrylamides, 1.5 gram N, N '-methylene-bisacrylamide and 36 gram PEG polymerizations and making in 3000 milliliters of 2-propyl alcohol.Polyreaction is in about 72.5 ℃ of beginnings, add during beginning 0.15 gram 2,2 '-the azo-bis-isobutyl cyanide initiator.In subsequently 200 minutes, add initiator in addition with 0.03 increment that restrains, be 0.45 gram until the initiator total amount that adds.During after initiator begins to add about 20 minutes, in about 180 minutes, in reactor, add 91 milliliters the solution of 20 gram PEG in 100 ml methanol.Polymerization temperature is maintained at about between 72 ℃ and 76 ℃.The total polymerization reaction times is 240 minutes.Reaction mixture is cooled to 25 ℃, adds 250 milliliters of 2-propyl alcohol under this temperature.For the isolating polymer stablizer, filter the polyacrylamide amine stabiliser dispersion liquid of gained.Polymer stabilizer is with 1000 milliliters of 2-propyl alcohol drip washing and dry in 60 ℃ of vacuum drying ovens.

Dsc analysis shows that this polymer stabilizer has a little endotherm(ic)peak (4.98 joule/gram) at 57.4 ℃, and this is caused by polyoxyethylene glycol.Dsc analysis is further illustrated in 189.6 ℃ and second endotherm(ic)peak (2.6 joule/gram) occur.Main fusing point is 291.3 ℃, and heat absorption is 114.5 joule/gram.Melt-flow speed (with gram expression in/10 minutes) is as follows: at 6-7 minute was 5.16, was 4.12 at 7-8 minute, was 4.03 at 8-9 minute.The number average granularity of this stablizer is 1.4 microns.

This polymer stabilizer is removed the polyoxyethylene glycol dispersion agent with the hot methanol washing, and then dry.Washed polymer stabilizer carries out dsc analysis, at 187.0 ℃ a little endotherm(ic)peak (2.6 joule/gram) is arranged.Main fusing point is 295.0 ℃, and heat absorption is 209.5 joule/gram.Washed stablizer did not flow at 6-9 minute.The existence of this explanation dispersion agent has disadvantageous effect to the observed value of melt-flow speed.Its number average granularity is 1.4 microns.

Molten polymer stablizer B is not by the solution in methyl alcohol (78.75 gram) joins in 7.00 cut butyl peroxy pivalates and the solution of 26.25 gram PEG in methyl alcohol (802.00 gram) and makes with 52.50 gram acrylamides and 0.53 gram 1,4 butanediol diacrylate.With gained vlil (about 74 ℃).When reaction begins to become oyster white, in 2 hours, add following two kinds of solution in the back flow reaction suspension simultaneously, wherein a kind of solution is 472.50 gram acrylamides and 4.72 grams 1, the solution of 4-butylene glycol diacrylate in methyl alcohol (708.75 gram), another kind are the solution of 26.25 gram PEG in methyl alcohol (172.50 gram).The gained reaction suspension was refluxed 2.5 hours.Filter this reaction suspension, the gained white solid is with methyl alcohol (400 milliliters) washing and 55 ℃ of-60 ℃ of dryings 6 hours.

Molten polymer stablizer C is not by in 2 hours, and with 14.3 kilograms of acrylamides and 145.15 grams 1,4-butyleneglycol diacrylamine joins in the reflux solution (about 64 ℃) of 1.44 kilograms of PEG in 48.06 kilograms of methyl alcohol and makes.In whole interpolation process, add total amount is the t-butyl peroxy pivalate polymerization starter of 195.04 grams in batches.Gained white solid methanol wash is in vacuum drying oven (6.75 * 10 ⁴Pa) 70 ℃ of dryings 1 day, and 100 ℃ of dryings 1 day.

Molten polymer stablizer D is not by restraining acrylamides with 201.8 gradually, 2.04 gram N, N '-methylene diacrylamine and the solution of 20.4 gram PEG in about 3800 ml methanol join in 8.2 gram t-butyl peroxy pivalate polymerization starters and the reflux solution of 10.2 gram PEG in about 5000 ml methanol and make.The gained reaction mixture refluxed is stirred until reacting completely.With reaction suspension cool to room temperature and the filtration that makes.The gained white solid is also dry with other methanol wash.

E. co-stabilizer compound component

The various melting co-stabilizer compounds that are used for embodiment are as follows:

" nylon " is nylon 66, and the ratio of nylon 6/10 and nylon 6 is 33/23/43 trimer.Recording its fusing point with dsc analysis is about 140 ℃.Before mixing, the nylon trimer is ground and sieve with 20 mesh sieve holes.The aperture of 20 mesh sieves is 1.44 millimeters.

" EVOH-1 " is the ethylene/vinyl alcohol copolymer, and it contains 29%(weight) ethene and 71%(weight) vinyl alcohol, (use H at 75 ℃ of waters ₃PO ₄Its pH value is adjusted to 3) washing 16 hours and the performance melt viscosity of the multipolymer of having purified is that 9500P(is at 210 ℃).From washing container, discharge acid wash water, with softening water the ethylene/vinyl alcohol copolymer was washed 4 hours at 75 ℃, dry then.According to U.S.P.4,766,168 described technology prepare co-stabilizer.With grinding and handle with the same method of above-mentioned nylon co-stabilizer.Measuring its fusing point with dsc analysis is about 187 ℃.

" EVOH-2 " contains 29%(weight) ethene and 71%(weight) the ethylene/vinyl alcohol copolymer of vinyl alcohol, the apparent melt viscosity that contains less than the multipolymer of 10ppm ash content of having purified is that 9500P(is at 210 ℃).

" TPU " is by 37%(weight) hexanodioic acid, 39%(weight) 1,4-butyleneglycol and 24%(weight) polyurethane elastomer formed of methylene radical two (4-phenyl isocyanate), its limiting viscosity is 1.33, it is measured according to ASTM D-2857 method, and (solvent is dimethyl formamide (DMF), temperature is 30 ℃, and concentration is the solution of 0.01% co-stabilizer in DMF).Recording fusing point with dsc analysis is about 150 ℃.

F. other adds compound

" PEG " is that molecular weight is the polyoxyethylene glycol of about 7000-9000, is commercially available, and trade mark is called Carbowax

8000(Union Carbide product).

" PPPE " is that molecular weight is about 13000 polyoxytrimethylene and polyethylene oxide block copolymer (commercially available trade mark is called Pluronic

F98, BASF Wyandotte Company product).

" PTFE " is irradiated polytetrafluorethylepowder powder under 7.5mrad.

" Si Oil " is polydimethylsiloxane, the end capped silicone oil of trimethylsiloxy group, and viscosity is 500 centipoises, demarcating molecular weight is 17250.

II. embodiment: with the compound modified stable polyacetal composition of Mierocrystalline cellulose of co-stabilizer

Embodiment 1-17 relates to the stable polyacetal composition of Mierocrystalline cellulose.

In routine 1-17 and routine C1-C18, with the thermostability of hot release formaldehyde (TEF) test method determination composition.The polyacetal composition sample of weighing is placed one in vitro, and this test tube is equipped with a lid, in order that nitrogen is added in the sample, removing any gas of emitting in the device, and sample is remained in the oxygen-free environment.This sample in the silicone oil bath 250 ℃ or 259 ℃ of heating.Nitrogen and any sodium sulfite aqueous solution bubbling that passes through 75 milliliter of 40 grams per liter that discharges.Formaldehyde of emitting and S-WAT reaction generate sodium hydroxide.Sodium hydroxide constantly neutralizes with the 0.1N HCl of standard.The milliliter of reference liquid is several, and mapping just obtains the result to test period.The percentage of formaldehyde of emitting is calculated with following formula:

（V）（N） (0.03×100)/(SW)

V is the volume (milliliter) of reference liquid in the formula

N is the equivalent concentration of reference liquid,

SW is example weight (gram)

Coefficient 0.03 is the milligramequivalent of formaldehyde, represents with gram/milligramequivalent.

List in the hot release formaldehyde result data sheet below, the header on this hurdle is the " CH of (weight) % under X ℃ ₂O ".Sample also is listed in the data sheet heat-up time.

The oxidation inhibitor that is used for embodiment 1-17 and C1-C18 is as follows:

(a) " oxidation inhibitor A " be triethylene glycol two (3-(3 '-tertiary butyl-4 '-hydroxyl-5 '-tolyl) propionic ester);

(b) " oxidation inhibitor B " is N, N '-hexa-methylene two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide);

(c) " oxidation inhibitor C " is four (methylene radical (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane.

Embodiment 1-6 and C1-C8

Among each composition as listed Table I A-IC below of embodiment 1-6 and C1-C8.To each example, each component all mixes, and in Werner and Pfleiderer twin screw extruder melting mixing, barrel temperature is set in 150 ℃-180 ℃, die head temperature is set in 200 ℃, screw speed is 150 rev/mins.Among each embodiment, the temperature when sample leaves die head is a melt temperature, and its scope is 221 ℃-224 ℃.Sample with TEF experimental examination melting mixing recited above.The results are shown among the following table I A-I C.

The result of table I A shows, when avicel cellulose and at least a co-stabilizer compound are added in the polyacetal together, the thermostability of gained polyacetal composition (example 1), only be better than with the co-stabilizer compound and without the thermostability of the identical polyacetal composition (routine C1) of avicel cellulose, also be better than usefulness avicel cellulose only and without the thermostability of the stable identical polyacetal composition of co-stabilizer compound (routine C2).Example 2 explanation is given the thermostability that it has improved when avicel cellulose and more than one co-stabilizer compounds are added in the polyacetal.

The result of table I B and table I C has also illustrated when avicel cellulose and at least a co-stabilizer and has combined when being added in the polyacetal, can obtain best heat stability.

Embodiment 7-11 and C9-C11

Each composition as listed of example 7-11 and C9-C11 is in the table II.The composition of these embodiment also contains 0.1%(weight) oxidation inhibitor B.Each component mixes, and carries out melting mixing, extrudes in 2.5 inch Sterling single screw extrusion machines, and barrel temperature is set in 150 ℃-200 ℃, and screw speed is 50 rev/mins.Temperature when sample leaves die head is a melt temperature, and its scope is 202 ℃-207 ℃.Each sample is carried out TEF test recited above.

Example 7-11 and C9-C11 the results are shown in the following table II.These results show that avicel cellulose is used in combination than the common polymeric amide stablizer of independent use (routine C9) with two kinds of co-stabilizers, and in very short test period, the effect of improving the polymeric amide thermostability is much better.These results further specify along with the reducing of avicel cellulose average particle size, and the thermostability of polyacetal increases.

Embodiment 12-13 and C12-C15

Each composition as listed of example 12-13 and C12-C15 is in the following table III.Each embodiment earlier mixes each component, melting mixing then, and under above-mentioned routine 1-6 the same terms, extrude.The sample of melting mixing carries out above-mentioned TEF test.The results are shown in the table III.The pH value of example C14 and C15 explanation fibrous cellulose is less than the result of 5.5 o'clock gained.

Embodiment 14-17 and C16-C18

Example 14-17 and each composition as listed of C16-C18 are in the following table IV.Except stablizer and oxidation inhibitor, every kind of composition also contains a kind of additive.Each component of each embodiment is melting mixing in 53 millimeters twin screw extruders, and barrel temperature is about 210 ℃.Temperature when sample leaves die head is a melt temperature, and its scope is 210 ℃-235 ℃.Each sample carries out above-mentioned TEF test.

The presentation of results of thermostability when the composition of test contains avicel cellulose and co-stabilizer, can reach best stability in long test period.

III. embodiment: the stable polyacetal composition of not molten polymer of using the phenol type antioxidant modification of amide containing

Embodiment 18-28 and C19-C27 relate to the stable polyacetal composition of not molten polymer with the phenol type antioxidant modification of at least a amide containing.

The phenol type antioxidant of amide containing that is used for routine 18-28 and C19-C27 is as follows:

" Amconl " is N, N '-hexa-methylene two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide), and this is and the identical oxidation inhibitor of top oxidation inhibitor B.

The oxidation inhibitor of not amide containing that is used for routine 18-28 and C19-C27 is as follows:

(a) " oxidation inhibitor A " be triethylene glycol two (3-(3 '-tertiary butyl-4 '-hydroxyl-5 '-tolyl) propionic ester);

(b) " oxidation inhibitor E " is 1,6-hexylene glycol two (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate);

(c) " oxidation inhibitor C " is four (methylene radical-(3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane;

(d) " oxidation inhibitor G " be 2,2 '-methylene radical-two-(4-methyl-6-t-butyl phenol);

(e) " oxidation inhibitor H " be 4,4 '-butylidene-two-(6-tertiary butyl-3-methylphenol);

(f) " oxidation inhibitor I " is two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamyl)-1, the 2-hydrazides;

(g) " oxidation inhibitor J " is three (methylene radical-(3,5-di-tert-butyl-4-hydroxy phenyl)-1,3,5-tricyanic acids; With

(h) " oxidation inhibitor K " is 1-Stearyl alcohol-(3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate).

In routine 18-28 and C19-C27, polyacetal composition mixes in forcing machine, is molded into the thick tensile strip of 1/8 inch then, measures its data.Describe the accurate extrusion condition of every group of sample below in detail.The tensile strip of each composition weighed in advance and be placed in 150 ℃ the circulated air oven, storage period is as shown in following table.Sample strip is distributed in the whole baking oven or average result that constantly the rotary sample bar is obtained all positions in the baking oven.When specific time cycle finishes, from baking oven, take out sample strip, weigh, press the ASTMD-638(0.2 inch/minute+prefix speed) method mensuration tensile strength and elongation.Weight loss percentage ratio is calculated as follows: (weight after 1-(is aging)/(weight before aging)) * 100

Embodiment 18 and C19-C24

(cylindrical shell is set 190 ℃ to composition in following table V A, 50/80 rev/min of screw speed, 50 pounds/inch of pressure in that 2 inch single screw extrusion machines of baffle plate screw rod and valve die head are housed ²) the middle mixing.The blended resin is injection molded as the thick tensile strip of 1/8 inch in Van Dorn 150 RS3 6 OZ. type reciprocating screw injectors, this injector is equipped with two evacuated moulds, and (injection/hold period is 45/20,1000 pounds/inch of pressure ²Gauge pressure, 200 ℃ of barrel temperatures, 90 ℃ of mould temperature).The tensile strip of each composition is placed in 150 ℃ of circulated air ovens, and storage period is as shown in following table V B.The data that table V B lists are three mean values that tensile strip records.

Table V A contains the not polyacetal composition of the phenol type antioxidant of molten polymer stablizer and amide containing

(weight) % (weight) % oxidation inhibitor (weight) %

Example polyacetal A is molten polymer oxidation inhibitor not

Stablizer B

18 99.40 0.50 AmConl 0.10

C19 99.40 0.50 A 0.10

C20 99.10 0.50 A 0.40

C21 99.40 0.50 E 0.10

C22 99.40 0.50 C 0.10

C23 99.40 0.50 G 0.10

C24 99.40 0.50 H 0.10

With example 18 and the present invention of C19-C24 comparative descriptions.In containing the polyacetal composition of molten polymer stablizer not, the phenol type antioxidant that adds amide containing with add the not phenol type antioxidant contrast of amide containing, the former can improve the agent steady in a long-term of said composition significantly.

Example C21 and example 18 illustrate that more clearlyly amide functional group is in the obvious effect that improves aspect the permanent stability.Unique difference of two compositions is that the composition of example 18 contains the oxidation inhibitor of amide containing, and the composition of C21 contains the not oxidation inhibitor of amide containing.Specifically, the oxidation inhibitor E of routine C21 is except containing ester functional group with the substituted amide functional group, and the oxidation inhibitor (AmConl) of rest part and example 18 amide containings is identical.The structure of oxidation inhibitor E is as follows:

The structure of the phenol type antioxidant AmConl of amide containing is as follows:

Contain not the composition of the example 21 of the phenol type antioxidant E of amide containing and compare with the composition of the example 18 of amide compound, the weight loss after the former 16 days is bigger 3 times than the latter.

Embodiment 19-20 and C25

As described in embodiment 18 and C19-C24,, extrude and be molded into tensile strip with the composition melting mixing among the table VI A.Handle tensile strip by the method that example 18 is identical with routine C1-C6.Result among the table VI B is three mean values that tensile strip records.

Table VI A contains the not polyacetal composition of the phenol type antioxidant of molten polymer stablizer and amide containing

(weight) % (weight) % (weight) %

Example polyacetal A is molten polymer oxidation inhibitor oxidation inhibitor not

Stablizer

B∶A

（30∶70）

19 99.40 0.50 AmConl 0.10

20 99.10 0.50 AmConl 0.40

C25 99.40 0.50 A 0.10

These results illustrate again, in the polyacetal composition that contains at least a not molten polymer stablizer, compare with there being not the phenol type antioxidant of amide containing when having the phenol type antioxidant of amide containing, its long-term thermal stability be improved significantly.After 16 days, the weight loss of the composition of the phenol type antioxidant of amide containing is approximately littler 4 times than the weight loss of the composition of the phenol type antioxidant of amide containing not.

Embodiment 21-28 and C26-C27

Composition among the table VII A mixes in 2 inch single screw extrusion machines.Demarcate about 210 ℃ of extruder barrel temperature.With about 207 ℃ extruder temperature and about 88 ℃ mould temperature, the resin of extruding is injection molded as the thick tensile strip of 1/8 inch.The tensile strip of each composition is placed in 150 ℃ of circulated air ovens, and the time of placement is as shown in following table VII B.The data that table VII B lists are the mean value that 5 tensile strips are measured.

The polyacetal composition of table VII B evaluation table VII A

Beginning is 150 ℃ of tests

0 day 10 days 15 days 16 days

TS/E TS/E/WL TS/E/WL TS/E/WL

Routine number (*/%) (*/%/%) (*/%/and %) (*/%/%)

21 671/40 495/4/1.77 501/5/4.62 -

22 683/21 668/9/0.27 - 582/4/0.83

23 678/23 668/10/0.33 - 578/5/0.67

24 672/27 638/8/0.31 - 566/5/0.91

25 670/23 599/6/0.32 - 564/6/1.07

26 681/17 544/5/0.56 - 554/6/3.19

27 685/21 625/8/0.68 - 554/5/1.35

28 673/36 644/8/0.32 - 602/5/0.58

C26 671/37 488/4/5.27 382/3/14.21 -

C27 680/21 403/4/11.26 305/3/20.08 -

The TS=tensile strength

The E=elongation

WL=weight loss

＊＝Kg/cm ²

Use-case 21-28 and routine C26-C27 relatively further specify the present invention.C26 is with example 21 comparative descriptions for example: when the phenol type antioxidant of amide containing and the phenol type antioxidant of amide containing not are added in the polyacetal composition that contains molten polymer stablizer not, at the appointed time, the stability of its characteristic properties is better than significantly and only adds the not stability of the identical polyacetal composition of the phenol type antioxidant of amide containing.Example C27 explanation has the resulting result of oxidation inhibitor of nitrogen-containing group, but this nitrogen-containing group is hydrazides functional group rather than amide functional group.The importance of amide functional group in these presentation of results oxidation inhibitor.Example 24-25 illustrates another feature of the present invention, can add processing aid in the promptly stable polyacetal composition and performance is reduced.At last, routine 21-28 explanation contain at least a amide containing phenol type antioxidant antioxidant mixture than the phenol type antioxidant that only contains amide containing not or more than one not the mixture of the phenol type antioxidant of amide containing can better keep the physicals of the stable polyacetal composition of molten polymer not.

IV. embodiment: with the stable polyacetal composition of not molten polymer of a kind of co-stabilizer compound and a kind of primary antioxidant modification

Example 29-38 and routine C28-C34 relate to the stable polyacetal composition of not molten polymer with melting co-stabilizer and at least a primary antioxidant modification.

The primary antioxidant that is used for these embodiment is as follows:

(a) " oxidation inhibitor A " be triethylene glycol two (3-(3 '-tertiary butyl-4 '-hydroxyl-5 '-tolyl) propionic ester);

(b) " oxidation inhibitor B " is N, N '-hexa-methylene two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide); This is identical with above-mentioned AmConl; With

(c) " oxidation inhibitor C " is four (methylene radical (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane.

In routine 29-38 and C28-C34, polyacetal composition mixes in forcing machine, is molded into the thick tensile strip of 1/8 inch then, determination data.The accurate extrusion condition of every group of sample is specified in down.The tensile strip of each composition is weighed in advance and is placed in 150 ℃ of circulated air ovens, and the time of placement is as shown in following table.Be distributed in the whole baking oven sample strip or continuous rotary sample bar, obtain the average result of placement location influence in the baking oven.When the specific time cycle finishes, from baking oven, take out sample, weigh, and press ASTM D-638(0.2 inch/minute pinblock speed) method test tensile strength and elongation.Weight loss is calculated as follows:

(weight after 1-(is aging)/(weight before aging)) * 100

Embodiment 29-32 and C28-C31.

Each composition of listing among the table VIII A is being equipped with 2 inch single screw extrusion machines of baffle plate screw rod and valve mould (190 ℃ of barrel temperatures, 50/80 rev/min of screw speed, 500 pounds/inch of pressure ²) the middle mixing.(injection/hold period is 45/20 to mixed resin, 1000 pounds/inch of pressure in the Van Dorn 150 RS3 6 OZ. type reciprocating screw injection moulding machines that two evacuated moulds are housed ²Gauge pressure, barrel temperature are set 200 ℃, 90 ℃ of mould temperature settings) be injection molded into the tensile strip of 1/8 inch.The tensile strip of each composition is placed in 150 ℃ of circulated air ovens, and the time of placement is as shown in following table VIII B.The gained data are the mean value that three tensile strips are measured.

The explanation of these examples, the improvement that contains the stability of all character of polyacetal composition of a small amount of melting co-stabilizer compound and primary antioxidant and permanent stability is better than not containing the identical composition of melting co-stabilizer compound.

Embodiment 33-35 and C32-C34

Each composition among the table IX A mixes in 2 inch single screw extrusion machines, and barrel temperature is about 210 ℃.Mixed resin is injection molded into the thick tensile strip of 1/8 inch, about 207 ℃ of barrel temperature, about 88 ℃ of mould temperature.

The tensile strip of each composition is placed in 150 ℃ of circulated air ovens, and the time of placement is as shown in following table IX B.The gained result is the average measurement result of 5 tensile strips.

These example explanations: contain blended melting co-stabilizer system and mix the polyacetal composition of primary antioxidant system, compare with the corresponding polyacetal composition that does not contain the melting co-stabilizer, the permanent stability of the former all properties are greater than the latter.

Embodiment 36-38

The composition of embodiment 36-38 contains PTFE and silicone oil additive.

Composition among the Table X A mixes with 53 millimeters twin screw extruders, and barrel temperature is about 210 ℃.The temperature that sample leaves forcing machine is a melt temperature, and its scope is 210 ℃-235 ℃.The blended resin is injection molded into the thick tensile strip of 1/8 inch in moulding press (barrel temperature is set 207 ℃, and the mould temperature is set 88 ℃).

The tensile strip of each composition is placed in 130 ℃ of circulated air ovens, and the time of placement is shown in following table X B.The gained data are the mean value that 5 tensile strips are measured.

Polyacetal composition among the table X B evaluation table X A

Beginning is 130 ℃ of tests

0 day 10 days 40 days

TS/E TS/E/WL TS/E/WL

Routine number (pound/%) (pound/%/and %) (pound/%/%)

36 9180/27 9660/14/0.28 8510/5.1/0.51

37 9690/20 10290/15/0.32 10260/12/0.74

38 9620/23 10210/16/0.40 9730/10/0.88

The TS=tensile strength

The E=elongation

WL=weight loss

Claims (37)

1, a kind of thermoplastic polyacetal composite (b) and (c) forms mainly by following (a):

(a) 0.05-5% (weight) is selected from the stablizer of avicel cellulose and fibrous cellulose,

(b) 0.05-4% (weight) is selected from polymeric amide, fusible hydroxyl polymer-containing, melting hydroxyl oligopolymer, at least a co-stabilizer compound in the Lewis base functional group's that the Lewis base functional group's that hydroxyl and at least one another kind are stronger than hydroxyl melting polymkeric substance and hydroxyl and at least one another kind are stronger than hydroxyl the melting oligopolymer and

(c) at least a polyacetal polymer of 91.0-99.9% (weight), requiring the average particle size of component (a) stablizer is 100 microns or littler, component (b) the melting hydroxyl polymer-containing or the atom in the oligopolymer main chain that also require directly or indirectly to link to each other with hydroxyl are kept apart less than 20 chain atoms, and component (b) is essentially nonacid material, also require above-mentioned percentage ratio only with component (a), (b) and total amount (c) be basic.

2, according to the composition of claim 1, wherein the pH value of component (a) cellulose stabiliser is 5.5-8.

3, according to the composition of claim 1, wherein component (c) polyacetal polymer is a homopolymer, and the pH value of component (a) cellulose stabiliser is 5.5-7, and component (b) co-stabilizer compound is gone up substantially and is nonacid material and non-basic material.

4, according to the composition of claim 1, wherein component (a) cellulose stabiliser is that average particle size is 50 microns or littler avicel cellulose.

5, according to the composition of claim 1, wherein component (a) cellulose stabiliser is that average particle size is 25 microns or littler avicel cellulose.

6, according to the composition of claim 1, wherein component (a) cellulose stabiliser is that average particle size is 10 microns or littler avicel cellulose.

7, according to the composition of claim 1, wherein component (a) cellulose stabiliser is a fibrous cellulose.

8, according to the composition of claim 7, wherein fibrous cellulose is by producing cellulosic bacterial derivation.

9, according to the composition of claim 1, wherein component (b) co-stabilizer compound is a polymeric amide.

10, according to the composition of claim 9, wherein polymeric amide is selected from (a) nylon 66, the ratio of nylon 6/10 and nylon 6 is 33/23/43 trimer, and (b) being dispersed in the nylon 6/6 in the vector resin and (c) being dispersed in nylon 66/ nylon 6 in the vector resin is 85/15 multipolymer.

11, according to the composition of claim 1, wherein component (b) co-stabilizer compound is melting hydroxyl polymer-containing or melting hydroxyl oligopolymer.

12, according to the composition of claim 11, wherein the melting hydroxyl polymer-containing is poly-(ethylidene vinyl alcohol).

13, a kind of thermoplastic polyacetal composite (b) and (c) forms mainly by following (a):

(a) 0.05-3.0%, (weight) at least a not molten polymer stablizer, be selected from the polymkeric substance that contains the formaldehyde activity hydroxy, the polymkeric substance that contains the formaldehyde reactive nitrogen base, the polymkeric substance that contains formaldehyde activity hydroxy and formaldehyde reactive nitrogen base simultaneously, atom in the main polymer chain that requirement is direct or indirect with the formaldehyde active group links to each other is kept apart by no more than 20 chain atoms, also require directly or indirectly and the quantity of the formaldehyde reactive nitrogen base that the atom in the main polymer chain links to each other is three times of the formaldehyde reactive nitrogen radix amount that exists in the main polymer chain at least

(b) 0.02-1.00%(weight) phenol type antioxidant of at least a amide containing and

(c) 96-99.93%(weight) at least a polyacetal polymer requires above-mentioned percentage ratio only with component (a), and total amount (b) and (c) be basic, and the number average granularity that also requires polymeric constituent in the composition (a) is less than 10 microns.

14, according to the composition of claim 13, also contain 0.05-0.50%(weight) oxidation inhibitor of at least a not amide containing, described weight percentage is with molten polymer stablizer not, polyacetal polymer, and the weight of the oxidation inhibitor of the oxidation inhibitor of amide containing and amide containing is not the basis.

15, according to the composition of claim 13 or 14, wherein the phenol type antioxidant of amide containing is selected from: 2,2 '-adipamide base diethyl-3-(3,5-di-tert-butyl-4-hydroxy phenyl) acid amides of propionic ester and β-(3,5-di-tert-butyl-4-hydroxy phenyl) propionic acid.

16, according to the composition of claim 13 or 14, wherein the phenol type antioxidant of amide containing is N, N '-hexa-methylene two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide).

17, according to the composition of claim 14, wherein the oxidation inhibitor of amide containing is not sterically hindered phenol oxidation inhibitor.

18, according to the composition of claim 17, wherein sterically hindered phenol oxidation inhibitor is selected from: triethylene glycol two (3-(3 '-tertiary butyl-4 '-hydroxyl-5 '-tolyl) propionic ester); Four (methylene radical (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane; Trimethylene (3,5-di-tert-butyl-4-hydroxy phenyl)-1,3,5 ,-tricyanic acid; With 1-Stearyl alcohol-(3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate).

19, a kind of thermoplastic polyacetal composite (b), (c) and (d) forms mainly by following (a):

(a) 0.05-3.0%(weight) at least a not molten polymer, be selected from the polymkeric substance that contains the formaldehyde activity hydroxy, the polymkeric substance that contains the formaldehyde reactive nitrogen base, reach the polymkeric substance that contains formaldehyde activity hydroxy and formaldehyde reactive nitrogen base simultaneously, require directly or indirectly with main polymer chain that the formaldehyde active group links to each other in atom on average kept apart each other by no more than 20 chain atoms, the quantity that also requires the formaldehyde reactive nitrogen base that atom direct or indirect and in the main polymer chain links to each other is three times of the formaldehyde reactive nitrogen radix amount that exists in the main polymer chain at least;

(b) 0.01-1.0%(weight) at least a melting co-stabilizer compound;

(c) 0.02-1.0%(weight) at least a primary antioxidant and

(d) 95-99.92%(weight) at least a polyacetal polymer;

Require above-mentioned percentage ratio only with component (a), (b), gross weight (c) and (d) be basic, and the number average granularity that also requires polymeric constituent in the composition (a) is less than 10 microns.

20, according to the composition of claim 19, wherein component (b) melting co-stabilizer compound is the polyacetal thermo-stabilizer, and it is selected from polymeric amide, the compound of amide containing, and carbamate, urea contains the compound of amine and the compound of hydroxyl.

21, according to the composition of claim 20, wherein the co-stabilizer compound of amide containing is a polymeric amide.

22, according to the composition of claim 21, wherein polymeric amide is a nylon 66, and nylon 6/10 and nylon 6 are respectively the ter-polymers of 33/23/43 weight percent.

23, according to the composition of claim 19, wherein component (b) melting co-stabilizer compound is the polymkeric substance or the oligopolymer of hydroxyl, wherein polymkeric substance or the atom in the oligopolymer main chain that directly or indirectly links to each other with hydroxyl on average kept apart by no more than 20 chain atoms each other, and the polymkeric substance of hydroxyl or oligopolymer are essentially nonacid material.

24, according to the composition of claim 23, wherein melting hydroxyl polymer-containing or oligopolymer are selected from: polyvinyl alcohol, poly-(ethylidene vinyl alcohol), poly-(methyl) acrylic acid hydroxy ester and vinyl alcohol/methylmethacrylate copolymer.

25, according to the composition of claim 24, wherein the melting hydroxyl polymer-containing is poly-(ethylidene vinyl alcohol).

26, according to the composition of claim 19, wherein component (c) primary antioxidant is selected from: the acid amides of β-(3,5-di-tert-butyl-4-hydroxy phenyl) propionic acid; 2,2 '-adipamide base diethyl-3-(3,5-di-tert-butyl-4-hydroxy phenyl) propionic ester; Triethylene glycol two (3-(3 '-tertiary butyl-4 '-hydroxyl-5 '-tolyl) propionic ester); With four (methylene radical (3,5-di-tert-butyl-4-hydroxyl hydrogenated cinnamate)) methane.

27, according to the composition of claim 19, wherein primary antioxidant is N, N '-hexa-methylene two (3,5-di-tert-butyl-4-hydroxyl hydrocinnamamide).

28, according to the composition of claim 1, wherein primary antioxidant is the mixture of more than one primary antioxidants.

29, according to the composition of claim 13 or 19, wherein component (a) not the molten polymer stablizer be polyacrylamide or PMAm.

30, according to the composition of claim 13 or 19, wherein component (a) not the molten polymer stablizer be polyacrylamide.

31, according to the composition of claim 1,13 or 19, wherein polyacetal polymer is a homopolymer.

32, according to the composition of claim 1,13 or 19, wherein polyacetal polymer is a multipolymer.

33, according to the composition of claim 1,13 or 19, wherein the number-average molecular weight of polyacetal polymer is 10,000-100,000.

34, the composition according to claim 1,13 or 19 further contains at least a co-stabilizer, oxidation inhibitor, pigment, tinting material, toughener, toughner, UV stablizer, hindered amine stabilizer, nucleator, lubricant, glass fibre and filler.

35, the composition according to claim 1,13 or 19 further contains at least a polytetrafluorethylepowder powder, polytetrafluoroethylene fiber and silicone oil.

36, the moulded products that makes by the composition of claim 1,13 or 19.

37, the preparation of compositions method of claim 1,13 or 19 comprises each component of stablizer and polyacetal polymer at the fusing point that is higher than polyacetal be lower than under the temperature that each component produces degraded and mix.