Polyoxymethylene polymers incorporating aldehyde scavengers

Abstract

A method for reducing the aldehyde content, extending the oxidative induction time (OIT), and / or increasing the thermal stability in a polyoxymethylene (POM) polymer comprises: (i) A compound XX comprising at least three moieties of formula (AA), each moiety (AA) comprising an amine moiety (-NH) attached ortho or meta to an amide moiety (-CONH), and each R 1 independently represent a substituent, and m is an integer of 0 to 4, and the three moieties (AA) are bonded via their respective amide nitrogen atoms to respective carbon atoms of the main fragment, which main fragment contains only carbon and hydrogen atoms and is saturated, with (ii) a compound XX, and an aldehyde scavenger selected from cyanoacetamide. TIFF2025525329000027.tif29170

Description

[Technical Field]

[0001] The present invention relates to polymeric materials, particularly but not exclusively polyoxymethylene (POM), which may be undesirably associated with aldehydes, for example, by their generation during manufacture, downstream melt processing and / or during use. [Background technology]

[0002] Polyoxymethylene (POM), also known as acetal, polyacetal, or polyformaldehyde, is a polymer that contains linear ether structures (CHO-) along its backbone. n This linearity is due to the high crystallinity, which can be up to 80%, and the viscosity of the polymer, which is 1.410-1.420 g / cm 3 In some cases, POM may be filled with, for example, glass or carbon fibers.

[0003] POMs are increasingly being used in numerous applications, including electrical and electronic equipment, consumer products, automotive and industrial machinery, medical devices, and building and construction.

[0004] POM may be sold as a copolymer or a homopolymer. Homopolymer POM has the following structure: [ka] It consists essentially of the repeating units described above.

[0005] The copolymer POM comprises the following repeating units: [ka]

[0006] It consists essentially of the repeating units described above.

[0007] Both homopolymer and copolymer POMs use methanol as the primary base material. For POM homopolymers, formaldehyde is synthesized by air oxidation of methanol, followed by the formation of acetal resins using an ionic initiator. The replacement of hydroxyl groups at the polymer chain ends with ester groups stabilizes the resin in POM homopolymers. POM copolymers are generally produced using trioxane (also produced starting from methanol) as a raw material. Approximately 2-3% epoxy compounds are copolymerized with trioxane to obtain stable POM copolymers. Chain-end capping may also be used. POM copolymer resins have greater stability but suffer from reduced crystallinity as a result of the interspersed carbon-carbon bond groups in their polymer chains. This polymer structure also confers excellent resistance to alkalis, hot water, and other chemicals, as well as long life at high temperatures and greater tolerance in processing conditions. Meanwhile, their tensile strength, stiffness, softening point, and melting point are all lower than those of acetal homopolymers.

[0008] Polyoxymethylene (POM) is inherently unstable and prone to polymer degradation. POM degradation occurs via chain scission or end-group decomposition. Common degradation products are formaldehyde, formic acid, cyclic acetals, and oligomers. Melt processing of POM causes polymer degradation and results in the production of formaldehyde. Formaldehyde emissions lead to workplace safety issues during polymer processing, limiting the use of this polymer in applications where air quality is critical, such as automotive applications.

[0009] Formaldehyde produced by polymer degradation can oxidize to formic acid and contribute to the hydrolysis of polymer chains. Apart from formaldehyde emissions, POM degradation can also result in mold deposits, loss of mechanical properties, and discoloration.

[0010] POM resins can also be susceptible to acid hydrolysis by mineral acids. For example, even low levels of chlorine in drinking water can lead to environmental stress cracking. Therefore, POM parts are stabilized to mitigate this degradation.

[0011] It is known to take measures to stabilize POM and reduce aldehyde emissions. For example, stabilizing measures may be applied during the final stage of POM production or during melt processing to form articles or masterbatches. Approaches developed to prevent POM degradation include the use of phenolic antioxidants to limit oxidative degradation, lubricants to reduce shear forces, acid scavengers to prevent formic acid hydrolysis, scavengers to react with free formaldehyde, endcapping to improve stability, light stabilizers, and / or comonomers.

[0012] In addition to the aldehyde generation problem mentioned above, POM is susceptible to thermally induced oxidative degradation. The relative thermo-oxidative stability of POM polymers may be assessed by measuring the Oxidative Induction Time (OIT). A relatively high OIT is preferred.

[0013] Although various types of stabilization packages are commercially available, it is difficult to both reduce aldehyde emissions in POM and improve its thermal stability, as indicated by an extension of the OIT. Summary of the Invention [Problem to be solved by the invention]

[0014] It is an object of the present invention to address one or more of the above problems. [Means for solving the problem]

[0015] According to a first aspect of the present invention, there is provided a method for reducing the aldehyde, e.g. formaldehyde, content in a polyoxymethylene (POM) polymer and / or increasing the oxidation induction time (OIT) and / or increasing the thermal stability, comprising treating said POM polymer, or a monomer, oligomer or prepolymer involved in the preparation of said POM polymer, with: (i) A compound XX comprising at least three moieties of the formula: [ka] Each moiety (AA) comprises an amine moiety (-NH2) attached ortho or meta to an amide moiety (-CONH), Each R 1 each independently represents a substituent, and m is an integer of 0 to 4. Compound XX, in which three moieties (AA) are bonded via their respective amide nitrogen atoms to respective carbon atoms of a main fragment, which main fragment contains only carbon and hydrogen atoms and is saturated; and (ii) For example, cyanoacetamides of the general formula: [ka] In the formula, R 60 and R 61 independently represent a hydrogen atom or an optionally substituted, preferably unsubstituted, alkyl, cycloalkyl or aromatic group; R 62 and R 63 independently represent a hydrogen atom or an optionally substituted, preferably unsubstituted, alkyl, cycloalkyl or aromatic group, or R 62 and R 63 together define an optionally substituted alkenyl group, cyanoacetamide and contacting the aldehyde scavenger with an aldehyde scavenger selected from:

[0016] References herein to reducing aldehydes appropriately refer primarily to formaldehyde, which, as noted, is particularly problematic with POM.

[0017] The method preferably reduces the aldehyde content in the POM as evaluated according to VDA-275. The method suitably improves the thermal stability of the POM, resulting in an extended OIT, which may be exemplified as described in Evaluation 3.

[0018] The POM suitably comprises -(CHO)- repeat units (referred to as "repeating unit X"). The POM may also comprise -(CHCHO)- repeat units (referred to as "repeating unit Y"). Preferably, in the POM, the sum of the mole percent of repeat units X and Y is at least 80 mole percent, preferably at least 90 mole percent, more preferably at least 95 mole percent, and especially about 100 mole percent.

[0019] In said POM, suitably the weight percent of the POM polymer made up of repeat units X and Y is at least 80 wt%, preferably at least 90 wt%, more preferably at least 95 wt%, especially at least 98 wt%.

[0020] The POM may suitably be a homopolymer POM consisting essentially of repeating unit X, or may be a copolymer POM which may comprise, or preferably consist essentially of, repeating units X and Y.

[0021] In the above compound XX, one R 1 Or each R 1may be selected from a halogen atom, or an optionally substituted hydrocarbon group, an alkoxy group, an amine group, an amide group, a phenol group, or a carboxylic acid group. The optionally substituted hydrocarbon may be substituted with one or more halogen atoms, or with an alkoxy group, an amine group, an amide group, a phenol group, or a carboxylic acid group. The optionally substituted hydrocarbon is preferably unsubstituted.

[0022] One R 1 Or each R 1 is an optionally substituted, preferably unsubstituted alkyl group, such as an optionally substituted, preferably unsubstituted C 1~20 , e.g. C 1~10 It may be an alkyl group. 1 R is a functional group related to improving compatibility, for example. 1 may be configured to improve the compatibility of compound XX in polymeric materials in which compound XX may be incorporated.

[0023] The or each m may be 0 or 1. Preferably, each m is 0. That is, other than the amine and amide moieties, each moiety (A) is unsubstituted.

[0024] Preferably, in compound XX, at least one moiety (AA) comprises an amine moiety (-NH2) attached ortho to an amide moiety (-CONH). Preferably, in each moiety (AA) in compound XX, the amine moiety is attached ortho to the amide moiety. In this case, preferably, m=0.

[0025] Preferably, the main fragment does not contain any cyclic or aromatic moieties. Preferably, the main fragment contains straight or branched chains.

[0026] The main fragment may contain 3 to 20 carbon atoms. Preferably, the main fragment contains 5 to 15 carbon atoms, more preferably 7 to 12 carbon atoms, and especially 8 to 10 carbon atoms. If the number of carbon atoms is n, the number of hydrogen atoms may be equal to 2n-1. Preferably, the main fragment contains 5 to 39 hydrogen atoms. Preferably, the main fragment contains 9 to 29 hydrogen atoms, more preferably 13 to 23 hydrogen atoms, and especially 15 to 19 hydrogen atoms.

[0027] In a preferred embodiment, the major fragment is C9H 17 It is a part.

[0028] The main fragment may comprise a linear chain containing 6 to 14 carbon atoms, preferably 6 to 10 carbon atoms, which may contain branching points to which chains containing 1 to 4 carbon atoms are attached.

[0029] The main fragment has the following general formula: [ka] where p, q and r are suitably integers in the range 1 to 10, preferably 1 to 5. Preferably, p is in the range 2 to 4, q is in the range 1 to 3 and r is in the range 2 to 6.

[0030] Preferably, the sum of the integers p, q and r is at least 4, preferably at least 6, more preferably at least 7. The sum may be less than 20, preferably less than 15, more preferably less than 10.

[0031] In compound XX, preferably the nitrogen atoms of the amide moiety (-CONH) are separated by at least 2, preferably at least 4, carbon atoms, and suitably not more than 10, for example not more than 7, carbon atoms.

[0032] The compound XX is represented by the following formula: [ka] where p, q and r are as defined above.

[0033] The compound XX is preferably [ka] is. In a preferred embodiment of the compound of formula XXV above, R 60 and R 61 each independently represents a hydrogen atom or an unsubstituted alkyl or cycloalkyl group; R 62 are independently a hydrogen atom or an unsubstituted alkyl or cycloalkyl group. In a particularly preferred embodiment, R 60 , R 61 , R 62 and R 63 Each represents a hydrogen atom.

[0034] References herein to "ppm" refer to "parts per million" by weight.

[0035] The aldehyde scavenger may be part of a formulation that contacts the POM polymer. The formulation may be a liquid formulation or a solid formulation. References herein to a material state (e.g., liquid) refer to the state at standard temperature and pressure (STP).

[0036] The formulation may comprise at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, especially at least 75% by weight of the carrier. The formulation may comprise less than 95% by weight of the carrier.

[0037] The formulation may comprise 50-95% by weight of a carrier, 5-50% by weight of the aldehyde scavenger, and 0-30% by weight of other additives, which may be selected from colorants, antioxidants, thickeners, process stabilizers, acid scavengers, lubricants, and UV additives.

[0038] Preferably, in the formulation, the sum of the weight percent of carrier(s) and the aldehyde scavenger is at least 80 weight percent, at least 90 weight percent, or at least 95 weight percent.

[0039] The formulation may be a solid masterbatch or a liquid formulation. When the formulation is a solid masterbatch, the solid masterbatch may comprise 60 to 95% by weight of a thermoplastic polymer, such as polyoxymethylene (POM).

[0040] The formulation may comprise 10 to 40% by weight of the aldehyde scavenger and 60 to 90% by weight of a thermoplastic polymer, such as POM.

[0041] The solid masterbatch may contain 0 to 10% by weight, preferably 0.5 to 10% by weight, of one or more antioxidants.

[0042] When the formulation is a liquid formulation, it may contain 50 to 90% by weight (e.g., 50 to 80% by weight) of a liquid carrier and 10 to 50% by weight (e.g., 20 to 50% by weight) of the aldehyde scavenger. The liquid carrier may be liquid at STP. The carrier is suitably one that has good solubility in the POM to which it is added. It may contain oil (e.g., vegetable oil or mineral oil) or glycol.

[0043] It is found that antioxidants can act synergistically in the method, and when used in the method, antioxidants may be included in the formulation or may otherwise be in contact with the POM.

[0044] The method may include contacting the POM with an antioxidant. A ratio, defined as the weight percent of the aldehyde scavenger divided by the weight percent of the antioxidant, may be at least 1.0, preferably at least 3.0. The ratio may be less than 20.0, preferably less than 10.0.

[0045] When the formulation is used in the method and / or contacted with POM in the method, the formulation may contain 0-10 wt. % of one or more antioxidants. The total wt. % of antioxidants in the formulation may be in the range of 0-10 wt. %, preferably in the range of 0.5-10 wt. %, or in the range of 0.5-7.0 wt. The formulation preferably contains at least 1.0 wt. % antioxidant.

[0046] The formulation may optionally include a phosphorus-containing antioxidant (e.g., phosphite-based compounds such as triphenyl phosphite, triphenyl phosphate-based compounds such as tris(2,4-di-t-butylphenyl) phosphate, diphosphonite-based compounds, and metal salts of hypophosphorous acid).

[0047] The antioxidant may (and preferably does) comprise a sterically hindered phenol compound. The antioxidant has the moiety: [ka] wherein R 50 and R 51 R independently contains at least four atoms, preferably selected from C atoms, H atoms, O atoms and N atoms, more preferably selected from C atoms and H atoms. 50 and R 51 is preferably saturated. 50 may represent a tertiary alkyl moiety, for example, a tertiary alkyl moiety containing at least 4 carbon atoms. 50 preferably represents a t-butyl moiety. 51 is C 1~4 It may also represent an alkyl moiety, especially a methyl group.

[0048] The antioxidant may comprise at least two moieties XXX.

[0049] The antioxidant may contain one or more oxyalkylene moieties, such as oxyethylene moieties.

[0050] The antioxidant may include one or more ester moieties.

[0051] The antioxidant preferably contains only C, H and O atoms.

[0052] The antioxidant has the following formula: [ka] wherein L 50 is preferably a linking moiety comprising an oxyalkylene moiety and one or more ester moieties. The antioxidant may be: [ka]

[0053] The method preferably reduces the aldehyde content in the POM polymer, so that the POM polymer contains 2 ppm or less aldehydes when evaluated according to VDA-275. The method also suitably extends the OIT.

[0054] According to a second aspect of the present invention, there is provided the use of compound XX or cyanoacetamide of the first aspect for reducing the aldehyde, e.g. formaldehyde, content in polyoxymethylene (POM) polymers and / or for extending the oxidation induction time (OIT) in POM and / or for increasing the thermal stability of POM.

[0055] According to a third aspect of the present invention there is provided a polyoxymethylene (POM) polymer having reduced aldehyde levels and / or extended oxidation induction time (OIT) and / or increased thermal stability, the polyoxymethylene (POM) polymer incorporating an aldehyde scavenger according to the first aspect or a product of the reaction of an aldehyde scavenger according to the first aspect with an aldehyde.

[0056] The POM polymer preferably contains 2 ppm or less aldehydes when evaluated according to VDA-275. The POM polymer suitably has improved thermal stability and / or an extended OIT, which may be exemplified as set forth in rating 3.

[0057] The POM polymer preferably comprises a residual carrier as described according to the first aspect.

[0058] The POM polymer preferably comprises an antioxidant as described according to the first aspect.

[0059] The POM polymer may be in pellet form.

[0060] The formulations described may be used in the manufacture of parts or in the manufacture of pellets, e.g. masterbatch pellets, which may be used in the manufacture of subsequent parts. Thus, according to a fourth aspect of the present invention, there is provided a method for producing an article, e.g. a moulded article, or pellets from a polyoxymethylene (POM) polymer, comprising: (a) selecting a formulation comprising a carrier and an aldehyde scavenger as described in the first and / or second aspects; (b) contacting a POM polymer with the formulation; (c) forming the POM polymer into an article, such as a molded article, or into pellets; A method is provided which includes:

[0061] The article or pellet preferably contains 2 ppm or less aldehydes when evaluated according to VDA-275. The article or pellet polymer suitably has improved thermal stability and / or an extended OIT, which may be exemplified as described in rating 3.

[0062] Preferably, in step (c), the POM polymer is suitably melt processed to define the article or pellet.

[0063] The articles or pellets may be defined by any process known in the art, including, for example, injection molding, blow molding, thermoforming, or extrusion.

[0064] The article or pellets may contain one or more colorants, for example, when an article is made, it may contain 5 to 500 ppm of colorant. The ppm mentioned above is preferably based on the amount of the POM polymer. The colorants described herein may be dyes or pigments. When pellets are made, the pellets may contain up to 60% by weight of a colorant, for example, titanium dioxide. Such pellets may suitably define a masterbatch containing 5 to 35% by weight of a filler, for example, suitably a colorant as described.

[0065] Preferably, in the molded article, the sum of the weight percent of the one or more POM polymers and the aldehyde scavenger is at least 90 weight percent, at least 95 weight percent, or at least 98 weight percent.

[0066] According to a fifth aspect of the present invention there is provided an article or pellet having reduced aldehyde levels and / or improved thermal stability and / or extended OIT, produced as described in the fourth aspect and / or comprising a POM polymer and an aldehyde scavenger as described.

[0067] The article or pellets preferably contain 2 ppm or less aldehydes when evaluated according to VDA-275. The article or pellets suitably have improved thermal stability and / or an extended OIT, which may be exemplified as set forth in rating 3.

[0068] Any aspect of any invention described herein may be combined, mutatis mutandis, with any other aspect of any invention described herein. DETAILED DESCRIPTION OF THE INVENTION

[0069] Specific embodiments of the present invention will now be described by way of example.

[0070] The following materials are referenced hereinafter: 2-Cyanoacetamide - commercially available from Fisher Scientific Irganox 1010 - commercially available pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate) obtained from Sigma Aldrich Carrier A - refers to Clearslip™ 2 available from ColorMatrix. Carrier A was selected to have good solubility for the POM copolymer used. Copolymer POM - refers to Ultraform S2320 POM copolymer obtained from BASF Iupital POM - refers to Iupital™ F20-03 POM copolymer. [Example]

[0071] Rating 1 - General procedure for determining the formaldehyde content of plaques The formaldehyde content of the samples is determined on injection-molded plaques (40 x 100 x 3 mm (W x L x D)). Formaldehyde levels are determined using a Markes Micro-Chamber / Thermal Extractor™ (µ-CTE™). This device is a versatile, compact unit with up to four small cylindrical chambers that allows sampling of chemicals emitted from products or materials. Emitted volatile and semivolatile organic compounds (VOCs and SVOCs) are collected in cartridges containing 2,4-dinitrophenylhydrazine for analysis by HPLC according to ISO 16000-3. Formaldehyde reduction is calculated based on the percentage reduction observed in formaldehyde levels of parts with the additive compared to a reference part without the additive. The evaluations described have been shown to be comparable to the automotive standard formaldehyde test, VDA-275.

[0072] Evaluation 2 - Procedures for measuring optical properties Plaques (size 95 x 165 x 3 mm (W x L x D)) prepared in a similar manner as described below and related controls were prepared and their optical properties (i.e., L * , a * and b * ) was evaluated using a Minolta CM-3700d spectrophotometer in transmission mode equipped with a D65 / 10° light source.

[0073] [Table 1]

[0074] Rating 3 - Oxidation Induction Time Test Oxidation induction time (OIT) tests were performed using heat flux differential scanning calorimetry (DSC) to analyze the thermal stability of POM samples. Approximately 5–6 mg of sample was heated from room temperature to 230°C under a nitrogen gas flow (50 ml / min) and held for 5 minutes. This gas flow was then switched to oxygen (50 ml / min) and held constant to determine the induction time. As discussed in V. Archodoulaki, S. Lueftl, and S. Seidler, “Oxidation induction time studies on the thermal degradation behavior of polyoxymethylene,” Polymer Testing, Vol. 25, No. 1, pp. 83–90, 2006, observations indicate that it is difficult to determine a clear onset temperature; therefore, the peak maximum of the OIT response, rather than the onset temperature, is interpreted as the OIT result.

[0075] Example 1 - Preparation of the acetaldehyde scavenger N,N'-(2-(4-(2-aminobenzamido)butyl)pentane-1,5-diyl)bis(2-aminobenzamide) (designated Compound X) Compound X has the following structure: [ka] 2H-Benzo[d][1,3]oxazine-2,4(1H)-dione (98.84 g, 3.5 equivalents, 605.9 mmol) was dissolved in dimethylformamide (500 mL) at room temperature. A solution of 4-(aminomethyl)octane-1,8-diamine (30.00 g, 1 equivalent, 173.1 mmol) in dimethylformamide (250 mL) was added dropwise to the reaction mixture. The reaction mixture was stirred overnight at room temperature until complete conversion was confirmed by LC-MS. The dimethylformamide was removed under reduced pressure to give a dark brown oil. Water (1 L) and ammonium hydroxide (25%, 50 mL) were added, and the product was extracted with dichloromethane. The dichloromethane was removed under reduced pressure, and the product was recrystallized in a mixture of methanol and acetonitrile. The solid was collected by filtration and dried to give N,N'-(2-(4-(2-aminobenzamido)butyl)pentane-1,5-diyl)bis(2-aminobenzamide) (51.0 g, 55.5% yield), the structure of which was confirmed by NMR and LC-MS, and the melting point was 160°C.

[0076] Example 2 - General procedure for preparing solid formulations Solid masterbatch formulations were prepared by blending the required amounts of base polymer, formaldehyde reducing agent, and optional antioxidant stabilizer in a twin-screw extruder. Pellets were cut using a strand cutter. Materials were prepared using a Labtech LTE444-16 twin-screw extruder using the following conditions:

[0077] [Table 2]

[0078] Example 3 - General Procedure for Preparing Liquid Formulations Liquid formulations were prepared by combining Liquid Carrier A and an optional dispersant (Solplus K240 (poly(12-hydroxystearic acid)-polyethyleneimine copolymer; CAS number 124578-12-7) in a liquid mixing vessel. To this was added an aldehyde scavenger and an optional antioxidant. The formulation may be milled to obtain the desired particle size. A rheology modifier may optionally be added. The formulation was mixed under vacuum to remove any remaining air.

[0079] Example 4 - Oxidation Induction Time (OIT) Testing of 2-Cyanoacetamide and Compound X Formulations and Comparison with Prior Art Formaldehyde Scavengers for POM The techniques identified in the prior art were extruded in Iupital POM and compared with the use of 4-cyanoacetamide and Compound X in terms of formaldehyde emissions and OIT. In each case, the antioxidant (Irganox 1010) was fixed at 0.3%. The results are shown in the table below.

[0080] [Table 3]

[0081] The results show that the use of both Compound X and 2-cyanoacetamide, in combination with a high OIT, results in very low formaldehyde emissions in POM. Note that cyanoacetamide provides a high level of formaldehyde reduction at only a 50% loading level compared to other scavengers. In addition, OIT is known to correlate with the concentration of antioxidant present in POM polymers. A synergistic effect was observed in the combination of Compound X or cyanoacetamide with antioxidants.

[0082] From the above, it can be concluded that both compound X and cyanoacetamide provide improvements and / or advantages over the referenced prior art.

[0083] Example 5 - Preparation of solid and liquid formulations containing Compound X Following the procedures described in Examples 2 and 3, solid and liquid formulations containing Compound X were prepared having the compositions detailed in the tables below.

[0084] Below, the aldehyde scavenger (AS) component was Compound X, the antioxidant was Irganox 1010, the liquid carrier for Formulation No. VIII was Carrier A, and the solid carrier for Formulation No. VII was Copolymer POM.

[0085] [Table 4]

[0086] Examples 6 and 7 - Evaluation of solid and liquid formulations containing Compound X Solid Formulation VII and Liquid Formulation VIII were added to Ultraform S2320 POM copolymer and plaques were produced by injection molding at let-down ratios (LDR) as shown in the table below. Formaldehyde emissions were evaluated as described in Evaluation 1, and L * , a * (D65), b * (D65) was evaluated as described in Evaluation 2.

[0087] [Table 5]

[0088] The control refers to the copolymer POM without any additives.

[0089] Both the solid masterbatch and liquid formulations provided significant formaldehyde reduction combined with reduced discoloration at low addition levels. Additionally, no discernible differences in oxidation induction time were observed between the formulation options, and both had a beneficial effect on OIT, as described in Example 4.

[0090] Example 8 - Preparation of solid and liquid formulations containing 2-cyanoacetamide Following the procedures described in Examples 2 and 3, solid and liquid formulations containing cyanoacetamide were prepared having the compositions detailed in the tables below, where the aldehyde scavenger (AS) component was 2-cyanoacetamide, the antioxidant was Irganox 1010, the liquid carrier for Formulation No. X was Carrier A, and the solid carrier for Formulation No. IX was copolymer POM.

[0091] [Table 6]

[0092] Examples 9 and 10 - Evaluation of solid and liquid formulations containing 2-cyanoacetamide Solid Formulation IX and Liquid Formulation X were added to Ultraform S2320 POM copolymer and plaques were produced by injection molding at let down ratios (LDR) as listed in the table below. Formaldehyde emissions were evaluated as described in Evaluation 1, and LDR was 0.01. * , a * (D65), b * (D65) was evaluated as described in Evaluation 2.

[0093] [Table 7]

[0094] The control refers to the copolymer POM without any additives.

[0095] Both the solid masterbatch and liquid formulations provided significant formaldehyde reduction combined with reduced discoloration at low addition levels. Additionally, no discernible differences in oxidation induction time were observed between the formulation options, and both had a beneficial effect on OIT, as described in Example 4.

[0096] Examples 11-15 - Use of Compound X as an Aldehyde Scavenger and the Synergistic Impact of Formulation Components on Formaldehyde Emissions Following the procedures outlined for Examples 6 and 7, individual components or mixtures of components contained in the described liquid formulations were dosed at the indicated levels into copolymer POM and then evaluated to determine their individual and / or joint effects on formaldehyde emissions and optical properties. Details of the components and mixtures evaluated and the results are provided in the table below.

[0097] When a carrier and antioxidant were used, these components were Carrier A and Irganox 1010, respectively.

[0098] [Table 8]

[0099] Examples 16-20 - Use of Cyanoacetamide as an Aldehyde Scavenger and the Synergistic Impact of Formulation Components on Formaldehyde Emissions Following the procedures outlined for Examples 6 and 7, individual components or mixtures of components contained in the described liquid formulations were dosed at the indicated levels into copolymer POM and then evaluated to determine their individual and / or joint effects on formaldehyde emissions and optical properties. Details of the components and mixtures evaluated and the results are provided in the table below.

[0100] When a carrier and antioxidant were used, these components were Carrier A and Irganox 1010, respectively.

[0101] [Table 9]

[0102] In the case of POM formulations, a wide range of materials may be incorporated into the formulation, including stabilizers such as hindered amine light stabilizers (HALS); acid scavengers, e.g., calcium stearate, hydrotalcite; lubricants, e.g., waxes; BaSO4, TiO2, carbon black, pigments, aromatic polyamides, silicon powder, polytetrafluoroethylene, and UV stabilizers.

[0103] The invention is not limited to the details of the above-described embodiments, and extends to any novel one or any novel combination of features disclosed in this specification (including the accompanying claims, abstract and drawings), or to any novel one or any novel combination of steps of any method or process so disclosed.

Claims

1. 1. A method for reducing the aldehyde content and / or increasing the oxidation induction time (OIT) and / or increasing the thermal stability in a polyoxymethylene (POM) polymer, comprising: subjecting said POM polymer, or a monomer, oligomer or prepolymer involved in the preparation of said POM polymer, to: (i) A compound XX comprising at least three moieties of the formula: 【Chemical 1】 Each moiety (AA) is an amine moiety (-NH) attached ortho or meta to the amide moiety (-CONH). ２ ), Each R １ each independently represents a substituent, and m is an integer of 0 to 4. Compound XX, wherein the three moieties (AA) are bonded via their respective amide nitrogen atoms to respective carbon atoms of a main fragment, the main fragment containing only carbon and hydrogen atoms and being saturated; and (ii) cyanoacetamide contacting the aldehyde scavenger with an aldehyde scavenger selected from A method comprising:

2. The method of claim 1 , wherein the POM is a homopolymer POM or a copolymer POM.

3. One R １ Or each R １ is an optionally substituted, preferably unsubstituted, alkyl group, the or each m is 0 or 1; At least one moiety (AA) comprises an amine moiety (-NH) attached ortho to the amide moiety (-CONH). ２ ), the main fragment does not contain any cyclic or aromatic moieties; The main fragment may be linear or branched. The method according to claim 1 or claim 2.

4. The main fragment is of the general formula: 【Chemistry 2】 wherein p, q and r are suitably integers ranging from 1 to 10, preferably from 1 to 5.

4. The method according to any one of claims 1 to 3.

5. The compound XX is of the formula 【Chemistry 3】 The method of claim 4.

6. The cyanoacetamide has the general formula: 【Chemistry 4】 In the formula, R ６０ and R ６１ independently represent a hydrogen atom or an optionally substituted, preferably unsubstituted, alkyl, cycloalkyl or aromatic group; 6. The method according to any one of claims 1 to 5.

7. R ６２ and R ６３ 7. The method of claim 6, wherein independently represent a hydrogen atom or an optionally substituted, preferably unsubstituted, alkyl, cycloalkyl or aromatic group.

8. R ６０ and R ６１ each independently represents a hydrogen atom or an unsubstituted alkyl or cycloalkyl group; R ６２ The method of claim 6 or claim 7, wherein each independently represents a hydrogen atom or an unsubstituted alkyl or cycloalkyl group.

9. R ６０ , R ６１ , R ６２ and R ６３ The method according to any one of claims 6 to 8, wherein each represents a hydrogen atom.

10. The aldehyde scavenger is part of a formulation that contacts the POM polymer, the formulation comprising: a solid masterbatch formulation comprising 10 to 40 wt. % of the aldehyde scavenger and 60 to 90 wt. % of a thermoplastic polymer, such as a POM; and a liquid formulation comprising 50 to 90% by weight (e.g., 50 to 80% by weight) of a liquid carrier and 10 to 50% by weight (e.g., 20 to 50% by weight) of said aldehyde scavenger; 10. The method according to any one of claims 1 to 9, selected from:

11. The method of claim 10, wherein the formulation comprises 0.5 to 10% by weight of an antioxidant.

12. The method of claim 11 , wherein the antioxidant comprises a highly sterically hindered phenolic compound.

13. The antioxidant is of the formula: 【Chemistry 5】 In the ceremony, L ５０ 13. The method of claim 11 or claim 12, wherein is a linking moiety comprising an oxyalkylene moiety and one or more ester moieties.

14. 14. The method of any one of claims 1 to 13, wherein the method reduces the aldehyde content in the POM polymer, the POM polymer containing 2 ppm or less aldehydes when evaluated according to VDA-275.

15. 15. The method of any one of claims 1 to 14, wherein the method is a method for extending the oxidation induction time (OIT).

16. Use of a compound XX or cyanoacetamide according to any one of claims 1 to 15 for reducing the aldehyde, e.g. formaldehyde, content in polyoxymethylene (POM) polymers and / or for extending the oxidation induction time (OIT) in POM and / or for increasing the thermal stability of POM.

17. 17. A polyoxymethylene (POM) polymer having reduced aldehyde levels and / or extended oxidation induction time (OIT) and / or increased thermal stability, the POM polymer incorporating an aldehyde scavenger according to any one of claims 1 to 16 or a product of the reaction of an aldehyde scavenger according to any one of claims 1 to 16 with an aldehyde.

18. 18. The polymer of claim 17, wherein the POM polymer contains 2 ppm or less of aldehydes when evaluated according to VDA-275.

19. 19. The polymer of claim 17 or claim 18 in pellet form.

20. 1. A method for producing an article, e.g., a molded article or pellets, from a polyoxymethylene (POM) polymer, comprising: (a) selecting a formulation comprising a carrier and an aldehyde scavenger according to any one of claims 1 to 19; (b) contacting the POM polymer with the blend; (c) forming the POM polymer into an article, such as a molded article, or into pellets; A method comprising:

21. 21. The method of claim 20, wherein the article or pellet contains 2 ppm or less of aldehydes when evaluated according to VDA-275.

22. 22. The method of claim 20 or claim 21, wherein the article or pellet has improved thermal stability and / or extended OIT.

23. 23. An article or pellet having reduced aldehyde levels and / or improved thermal stability and / or extended OIT, produced as claimed in any one of claims 20 to 22.

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