Particle blend, master batch, and method for producing resin composition

Abstract

The invention provides a granular blend, a master batch using the granular blend, and a method for producing a resin composition. The particle blend contains: a master batch (1) containing 0.5-3.0 parts by mass of a formaldehyde scavenger (B) per 100 parts by mass of a polyacetal resin (A) having a melt volume rate (MVR) of 5-50 cm3 / 10 min as measured in accordance with ISO 1133 under the conditions of 190 DEG C and a load of 2.16 kg by weight, and particles (2) containing 0.5-3.0 parts by mass of the formaldehyde scavenger (B) per 100 parts by mass of a polyacetal resin (A) having a melt volume rate (MVR) of 5-50 cm3 / 10 min as measured in accordance with ISO 1133; the particles (2) contain a polyacetal resin (C) having a melt volume rate (MVR) of 0.1-4 cm3 / 10 min or less as measured in accordance with ISO 1133 under the conditions of 190 DEG C and a load of 2.16 kg weight.

Description

Technical Field

[0001] This invention relates to a method for manufacturing particulate blends, masterbatches, and resin compositions. Background Technology

[0002] Polyacetal resins possess high mechanical strength and rigidity, excellent oil and organic solvent resistance, and are well-balanced across a wide temperature range. Furthermore, they exhibit good processability. Therefore, polyacetal resins are widely used as representative engineering plastics in OA equipment, digital home appliances, automotive parts, and other industrial components.

[0003] However, polyacetal resins are prone to producing formaldehyde, therefore, the process of incorporating formaldehyde scavenging agents into polyacetal resins is carried out (Patent Document 1, Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-137386

[0007] Patent Document 2: Japanese Patent Application Publication No. 2023-030823 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] As described above, the process involves incorporating a formaldehyde scavenger into polyacetal resin. However, when a formaldehyde scavenger is incorporated into a high-viscosity polyacetal resin and melt-blended, the shear exothermic reaction within the extruder becomes significant. Consequently, a large amount of the formaldehyde scavenger is consumed during melt-blending. Furthermore, the molded articles formed from such resin compositions suffer from insufficient formaldehyde capture. Increasing the amount of formaldehyde scavenger has also been considered, but this causes mold contamination during molding.

[0010] The purpose of this invention is to solve the above-mentioned problems, and to provide a particulate blend with high formaldehyde capture efficiency and low mold contamination, a method for manufacturing a masterbatch and resin composition using the above-mentioned particulate blend, wherein the particulate blend comprises a high-viscosity polyacetal resin and a formaldehyde capture agent.

[0011] Problem Solving Methods

[0012] Based on the above problems, the inventors conducted research and found that the above problems can be solved by adding a formaldehyde scavenger to a polyacetal resin with a relatively low viscosity, granulating it, and then blending it with particles containing a high-viscosity polyacetal resin.

[0013] Specifically, the above problems were solved in the following way.

[0014] <1> A particulate blend comprising a masterbatch (1) and particles (2),

[0015] In the aforementioned masterbatch (1), the melt volumetric velocity (MVR) measured according to ISO 1133 at 190°C and a load of 2.16 kg is 5~50 cm⁻¹. 3 100 parts by weight of polyacetal resin (A) contains 0.5 to 3.0 parts by weight of formaldehyde scavenger (B).

[0016] The particles (2) described above contain melt volumetric velocity (MVR) of 0.1 to 4 cm⁻¹, measured according to ISO 1133 at 190°C and with a load of 2.16 kg. 3 Polyacetal resin (C) with a score of less than 10.

[0017] <2> According to the particulate blend described in <1>, wherein,

[0018] The masterbatch (1) contains 3 to 25 parts by weight relative to 100 parts by weight of the above-mentioned particles (2).

[0019] <3> The particulate blend according to <1> or <2>, wherein,

[0020] The formaldehyde scavenger (B) mentioned above contains at least one selected from hydrazide compounds, hydrazones of hydrazide compounds, guanidine compounds and urea compounds.

[0021] <4> A masterbatch, wherein,

[0022] The melt volumetric velocity (MVR) is 5~50 cm³ / h as measured according to ISO 1133 at 190°C and with a load of 2.16 kg. 3 100 parts by weight of polyacetal resin (A) containing 0.5 to 3.0 parts by weight of formaldehyde scavenger (B).

[0023] <5> According to the masterbatch described in <4>, wherein,

[0024] The formaldehyde scavenger (B) mentioned above contains at least one selected from hydrazide compounds, hydrazones of hydrazide compounds, guanidine compounds and urea compounds.

[0025] <6> A method for manufacturing a resin composition, the method comprising:

[0026] The melt volumetric velocity (MVR) measured according to ISO 1133 at 190°C and with a load of 2.16 kg is 0.1~4 cm. 3 Polyacetal resin (C) with a content of less than 10 parts is melt-blended with masterbatch (1).

[0027] In the aforementioned masterbatch (1), the melt volumetric velocity (MVR) measured according to ISO 1133 at 190°C and a load of 2.16 kg is 5~50 cm⁻¹. 3 100 parts by weight of polyacetal resin (A) containing 0.5 to 3.0 parts by weight of formaldehyde scavenger (B).

[0028] The effects of the invention

[0029] This invention provides a method for manufacturing particulate blends, masterbatches, and resin compositions that have high formaldehyde capture efficiency and are less likely to cause mold contamination. The particulate blends contain high-viscosity polyacetal resin and formaldehyde capture agent. Detailed Implementation

[0030] The following describes a specific embodiment (hereinafter referred to as "this embodiment"). It should be noted that the following embodiment is an example used to illustrate the present invention, and the present invention is not limited to this embodiment.

[0031] It should be noted that in this specification, "~" is used to indicate the lower and upper limits of the values ​​contained before and after it.

[0032] Unless otherwise specified, all physical property values ​​and characteristic values ​​in this specification refer to values ​​at 23°C.

[0033] Unless otherwise specified, in cases where the measurement methods described in the standards shown in this instruction manual vary depending on the year, the standards at the time of January 1, 2023 shall prevail.

[0034] The particulate blend of this embodiment is characterized in that it comprises a masterbatch (1) and particles (2), wherein the masterbatch (1) has a melt volumetric velocity (MVR) of 5 to 50 cm³ / h relative to the conditions measured according to ISO 1133 at 190°C and a load of 2.16 kg. 3 100 parts by weight of polyacetal resin (A) containing 0.5 to 3.0 parts by weight of formaldehyde scavenger (B), wherein the above particles (2) contain a melt volumetric velocity (MVR) of 0.1 to 4 cm⁻¹ as measured according to ISO 1133 at 190°C and a load of 2.16 kg. 3 Polyacetal resin (C) with a score of less than 10.

[0035] By configuring it in this way, a high-viscosity polyacetal resin and formaldehyde scavenger are obtained. This particulate blend has a high formaldehyde scavenging effect and is not prone to causing mold contamination.

[0036] Previously, when formaldehyde scavengers were incorporated into polyacetal resins, the two were directly compounded using an extruder. During compounding, the extruder temperature was typically set to around 200°C for the polyacetal resin. However, it is known that even when melt-blending high-viscosity polyacetal resins at around 200°C, significant shear exothermic reactions occur within the extruder, causing the resin temperature to exceed the extruder's set temperature. Furthermore, this increased resin temperature results in a large amount of formaldehyde scavenger being consumed within the extruder.

[0037] Based on the above situation, in this embodiment, the MVR is pre-set to be 5~50cm. 3 A 10-point polyacetal resin (A) is mixed with a formaldehyde scavenger (B) and melt-blended to form a masterbatch. The masterbatch is then mixed with an MVR of 0.1~4cm. 3 Particles of polyacetal resin (C) with a content of less than 10% were blended. Using this method, formaldehyde scavenger (B) could be incorporated into the polyacetal resin during compounding (particle production) without generating excessive shear heat. It was found that the heating process applied to the formaldehyde scavenger (B) could be performed only during molding, avoiding unnecessary consumption of the formaldehyde scavenger (B). As a result, despite using a high-viscosity polyacetal resin and incorporating a formaldehyde scavenger, a particle blend with sufficiently high formaldehyde scavenging efficiency and reduced mold contamination was obtained.

[0038] The following is a detailed description of this embodiment.

[0039] <Masterbatch (1)>

[0040] In the masterbatch (1) of this embodiment, the melt volumetric velocity (MVR) is 5 to 50 cm⁻¹, as measured according to ISO 1133 at 190°C and a load of 2.16 kg. 3 100 parts by weight of polyacetal resin (A) containing 0.5 to 3.0 parts by weight of formaldehyde scavenger (B).

[0041] In such a masterbatch (1), excessive shear heat is not generated during the melt mixing process for masterbatch production, thus minimizing the consumption of formaldehyde scavenger (B) during melt mixing.

[0042] <<Polyacetal Resin (A)>>

[0043] Masterbatch (1) contains a melt volumetric velocity (MVR) of 5 to 50 cm⁻¹, measured according to ISO 1133 at 190°C and a load of 2.16 kg. 3 / 10 points of polyacetal resin (A).

[0044] The melt volumetric velocity (MVR) of the polyacetal resin (A), measured according to ISO 1133 at 190°C and with a load of 2.16 kg, is preferably 7 cm⁻¹. 3 / 10 points or more, preferably 10cm 3 / 10 points or above, further preferred to be 15cm 3 / 10 points or above, with 20cm being the most preferred. 3 / 10 points or above, further preferred to be 25cm 3 / 10 points or above, and preferably 45cm 3 / 10 points or less, preferably 40cm 3 / 10 points or less, further preferably 35cm 3 / 10 points or less, with 30cm being a further preferred size 3 / 10 points or less. By setting it above the aforementioned lower limit, shear exothermics during melt mixing can be suppressed, and the consumption of formaldehyde scavenging agent can be suppressed, thus tending to further improve the formaldehyde scavenging effect. In addition, by setting it below the aforementioned upper limit, there is a tendency to improve continuous productivity by preventing wire cutting during masterbatch manufacturing.

[0045] The masterbatch (1) in this embodiment may contain only one type of polyacetal resin (A), or it may contain two or more types. When it contains two or more types, the MVR of the mixture is preferably within the range described above.

[0046] As long as the above MVR is met, the type of polyacetal resin (A) is not particularly limited. It can be a homopolymer containing only divalent oxymethylene as a structural unit, or a copolymer containing divalent oxymethylene and divalent oxyalkylene with 2 or more carbon atoms as structural units.

[0047] Examples of oxoalkylene groups having 2 or more carbon atoms include oxoethylene, oxopropylene, and oxobutylene.

[0048] In the polyacetal resin (A), the proportion of oxoalkylene groups with 2 or more carbon atoms in the total molar number of oxomethyl groups and oxoalkylene groups with 2 or more carbon atoms is not particularly limited, and for example, it can be 0.5 to 10 mol%. The number of carbon atoms in the oxoalkylene groups can be 2 or more, preferably 6 or less, and more preferably 4 or less.

[0049] To manufacture the aforementioned polyacetal resin (A), trialkylene is typically used as the main raw material. Furthermore, to introduce alkylene groups with 2 to 6 carbon atoms into the polyacetal resin (A), cyclic methylal or cyclic ethers can be used, for example. Specific examples of cyclic methylal include 1,3-dioxolane, 1,3-dialkylene, 1,3-dioxane, 1,3-dioxane, 1,3-dioxane, 1,3,5-trioxane, and 1,3,6-trioxane. Specific examples of cyclic ethers include ethylene oxide, propylene oxide, and butane oxide. To introduce ethylene into the polyacetal resin (A), 1,3-dioxolane can be used, for example; to introduce propylene oxide, 1,3-dialkylene can be used; and to introduce butylene, 1,3-dioxane can be used.

[0050] It should be noted that in polyacetal resin (A), it is preferable to have a low amount of hemiacetal terminal groups, a low amount of formyl terminal groups, and a low amount of terminal groups that are unstable to heat, acid, and alkali. Here, hemiacetal terminal groups refer to groups represented by -OCH2OH, and formyl terminal groups refer to groups represented by -CHO.

[0051] In this embodiment, the content of polyacetal resin (A) in the masterbatch (1) is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 97% by mass or more, and even more preferably 98% by mass or more. Furthermore, the upper limit of the content of polyacetal resin (A) is the amount of polyacetal resin (A) that consists entirely of the formaldehyde scavenger (B).

[0052] The masterbatch (1) in this embodiment may contain only one type of polyacetal resin (A), or it may contain two or more types. When it contains two or more types, the total amount is preferably within the range described above.

[0053] <<Formaldehyde Scavenger (B)>>

[0054] In the masterbatch (1) of this embodiment, formaldehyde scavenger (B) is contained in a ratio of 0.5 to 3.0 parts by weight relative to 100 parts by weight of polyacetal resin (A).

[0055] The type of formaldehyde scavenger (B) used in this embodiment is not particularly limited, and compounds used as formaldehyde scavengers for polyacetal resins can be widely used.

[0056] As a formaldehyde scavenger (B), it is preferably a compound containing a nitrogen atom, more preferably containing at least one selected from acylhydrazine compounds, hydrazones of hydrazine compounds, guanidine compounds and urea compounds, and even more preferably containing at least one selected from acylhydrazine compounds and urea compounds.

[0057] As an acylhydrazine compound, an acylhydrazine compound having two or more acylhydrazine groups is preferred.

[0058] Examples of diacylhydrazide compounds include aliphatic diacylhydrazide compounds and aromatic diacylhydrazide compounds.

[0059] Examples of aliphatic diacylhydrazides include carbodihydrazides, oxalate diacylhydrazides, malonate diacylhydrazides, succinate diacylhydrazides, glutarate diacylhydrazides, adipic acid diacylhydrazides, azelate diacylhydrazides, sebacylhydrazides, dodecanoic acid diacylhydrazides (1,12-dodecanoic acid diacylhydrazides), 1,18-octadecanoic acid diacylhydrazides, stearate diacylhydrazides, maleate diacylhydrazides, fumarate diacylhydrazides, and 7,11-octadecadiene-1,18-dicarbonylhydrazides.

[0060] Examples of aromatic diacylhydrazides include isophthalic acid diacylhydrazide, terephthalic acid diacylhydrazide, 1,5-naphthalenedicarbazide, 1,8-naphthalenedicarbazide, 2,6-naphthalenedicarbazide, 4,4'-oxybisbenzenesulfonylhydrazide, and 1,5-diphenylcarbazide.

[0061] The acylhydrazine compound used in this embodiment is preferably an acylhydrazine compound represented by the following formula (1).

[0062] Equation (1)

[0063] [Chemical Formula 1]

[0064]

[0065] (In formula (1), R11 represents an aliphatic hydrocarbon group with 2 to 18 carbon atoms, an alicyclic hydrocarbon group with 6 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 10 carbon atoms; R12 to R15 represent hydrogen atoms or alkyl groups with 1 to 6 carbon atoms, respectively; R12 and R13, and R14 and R15 are optionally bonded to each other to form a ring.)

[0066] In formula (1), R11 represents an aliphatic hydrocarbon group with 2 to 18 carbon atoms, an alicyclic hydrocarbon group with 6 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 10 carbon atoms, preferably an aliphatic hydrocarbon group with 2 to 18 carbon atoms. The aliphatic hydrocarbon group with 2 to 18 carbon atoms preferably has 16 or less carbon atoms, more preferably 14 or less carbon atoms, and even more preferably 12 or less carbon atoms.

[0067] The aforementioned aliphatic hydrocarbon groups can be saturated or unsaturated, and can be linear or branched. Specific examples of aliphatic hydrocarbon groups include butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecanylene, octadecylene, and nonadecanylene, etc.

[0068] The aforementioned alicyclic hydrocarbon groups can be saturated or unsaturated.

[0069] Examples of alicyclic hydrocarbon groups include cycloalkylene groups with 6 to 10 carbon atoms. Examples of cycloalkylene groups include cyclohexylene groups.

[0070] Examples of aromatic hydrocarbon groups include phenylene and naphthylene aryl groups.

[0071] A substituent may be optionally bonded to at least a portion of the carbon atoms of the aromatic hydrocarbon group. Examples of such substituents include halogen groups, nitro groups, and alkyl groups having 1 to 20 carbon atoms.

[0072] In formula (1), R12 to R15 are preferably hydrogen atoms, methyl and ethyl atoms, respectively, and more preferably hydrogen atoms.

[0073] As specific examples of compounds represented by formula (1), adipic dihydrazide and 1,12-dodecanoic dihydrazide can be cited.

[0074] As the hydrazone of the hydrazine compound, it is preferably a hydrazone of at least one hydrazine compound selected from the compounds represented by formula (2) below and the compounds represented by formula (3) below.

[0075] Equation (2)

[0076] [Chemical Formula 2]

[0077]

[0078] (In formula (2), R1 represents an aliphatic hydrocarbon group with 4 to 20 carbon atoms, an alicyclic hydrocarbon group with 6 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 10 carbon atoms. R2 to R5 each independently represent a hydrogen atom or an alkyl group with 1 or 2 carbon atoms. At least one of R2 and R3 represents an alkyl group with 1 or 2 carbon atoms, and at least one of R4 and R5 represents an alkyl group with 1 or 2 carbon atoms.)

[0079] In formula (2), R1 represents an aliphatic hydrocarbon group with 4 to 20 carbon atoms, an alicyclic hydrocarbon group with 6 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 10 carbon atoms.

[0080] The aforementioned aliphatic hydrocarbon groups can be saturated or unsaturated, and can be straight-chain or branched.

[0081] Specific examples of aliphatic hydrocarbon groups include alkylene groups such as butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecanylene, octadecylene, nonadecanylene, and eicosylene.

[0082] The aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group with 6 to 12 carbon atoms. In this case, the reactivity of the hydrazone of the hydrazine compound with formaldehyde is further enhanced, which can more effectively suppress the generation of formaldehyde. In addition, mold contamination during molding and processing can be more effectively suppressed.

[0083] The aforementioned alicyclic hydrocarbon groups can be saturated or unsaturated.

[0084] Examples of alicyclic hydrocarbon groups include cycloalkylene groups with 6 to 10 carbon atoms. Examples of cycloalkylene groups include cyclohexylene groups.

[0085] Examples of aromatic hydrocarbon groups include phenylene and naphthylene aryl groups.

[0086] A substituent may be optionally bonded to at least a portion of the carbon atoms of the aromatic hydrocarbon group. Examples of such substituents include halogen groups, nitro groups, and alkyl groups having 1 to 20 carbon atoms.

[0087] In formula (2), R2 to R5 independently represent hydrogen atoms or alkyl groups with 1 or 2 carbon atoms, at least one of R2 and R3 represents an alkyl group with 1 or 2 carbon atoms, and at least one of R4 and R5 represents an alkyl group with 1 or 2 carbon atoms.

[0088] In formula (2), it is preferred that R2 and R4 are ethyl atoms and R3 and R5 are hydrogen atoms, and that R2 and R4 are methyl atoms and R3 and R5 are hydrogen atoms or methyl atoms.

[0089] In this case, the reactivity of the hydrazone of the hydrazine compound with formaldehyde is further enhanced, which can more effectively inhibit the production of formaldehyde.

[0090] Specific examples of compounds represented by formula (2) above include: 1,12-bis[2-(1-methylethoxy)hydrazyl]]-1,12-dodecanedione, 1,12-bis(2-ethoxyhydrazyl)-1,12-dodecanedione, 1,12-bis(2-propenylidenehydrazyl)-1,12-dodecanedione, 1,12-bis[2-(1-methylpropenylidenehydrazyl]-1,12-dodecanedione, 1,12-bis[2-(1-ethylpropenylidenehydrazyl]-1,12-dodecanedione, 1,10-bis[2-(1-methylethoxy)hydrazyl]]-1,10-decanedione, 1,10-bis(2-propenylidenehydrazyl)-1, 10-Decanedione, 1,10-bis(2-propenylidenehydrazyl)-1,10-decanedione, 1,10-bis[2-(1-methylpropenylidene)hydrazyl]-1,10-decanedione, 1,10-bis[2-(1-ethylpropenylidene)hydrazyl]-1,10-decanedione, 1,6-bis[2-(1-methylethylpropenylidene)hydrazyl]-1,6-hexanedione, 1,6-bis(2-ethylpropenylidene)hydrazyl)-1,6-hexanedione, 1,6-bis(2-propenylidene)hydrazyl]-1,6-hexanedione, 1,6-bis[2-(1-methylpropenylidene)hydrazyl]-1,6-hexanedione, 1,6-bis[2-(1-ethylpropenylidene)hydrazyl]-1,6-hexanedione, etc.

[0091] Equation (3)

[0092] [Chemical Formula 3]

[0093]

[0094] (In formula (3), R8 represents an aliphatic hydrocarbon group with 4 to 20 carbon atoms, an alicyclic hydrocarbon group with 6 to 10 carbon atoms, or an aromatic hydrocarbon group with 6 to 10 carbon atoms. R6 and R7 each independently represent an alicyclic hydrocarbon group with 3 to 12 carbon atoms.)

[0095] In equation (3), R8 is the same as R1, and the preferred range is also the same.

[0096] R6 and R7 independently represent alicyclic hydrocarbon groups with 3 to 12 carbon atoms.

[0097] Examples of alicyclic hydrocarbon groups with 3 to 12 carbon atoms include cyclohexylene.

[0098] Specific examples of compounds represented by the above formula (3) include 1,12-bis(2-cyclohexylhydrazyl)-1,12-dodecanedione, 1,10-bis(2-cyclohexylhydrazyl)-1,10-decanedione, 1,6-bis(2-cyclohexylhydrazyl)-1,6-hexanedione, etc.

[0099] Examples of guanidine compounds include benzoguanidine and N-hydroxymethylated benzoguanidine.

[0100] As a urea compound, it refers to a compound having the -(HN)2C(=O) structure, and there are no particular limitations on its types, etc.

[0101] Examples of urea compounds include urea, ethylene urea, allantoin, biuret, dimethylethylene urea, acrylamide, and tetrabutylurea, preferably containing ethylene urea and / or allantoin, and more preferably containing ethylene urea.

[0102] The formaldehyde scavenger (B) used in this embodiment preferably has a molecular weight of 60 or more, more preferably 86 or more. Furthermore, the upper limit is preferably 1000 or less, more preferably 800 or less, and even more preferably 500 or less.

[0103] Relative to 100 parts by weight of polyacetal resin (A), the content of masterbatch (1) in this embodiment is 0.5 parts by weight or more, more preferably 1 part by weight or more, and further preferably 3.0 parts by weight or less, and more preferably 2.5 parts by weight or less. By setting it to the lower limit or above, there is a tendency to more effectively suppress the generation of formaldehyde, especially when the residence time in the molding machine is long. By setting it to the upper limit or below, the effect of suppressing mold contamination is more effective.

[0104] The masterbatch (1) of this embodiment may contain only one formaldehyde scavenger (B) or two or more. When it contains two or more, the total amount is preferably within the range described above.

[0105] The masterbatch (1) in this embodiment may contain other components besides polyacetal resin (A) and formaldehyde scavenger (B), or it may not contain any of them.

[0106] Other components include compounds containing functional groups (such as melamine compounds), heat stabilizers, antioxidants, weather stabilizers, light stabilizers, ultraviolet absorbers, release agents, lubricants, nucleating agents, antistatic agents, antibacterial agents, and colorants (pigments, dyes). They can be used alone or in combination of two or more.

[0107] The content of these other components is preferably less than 5% by mass of the masterbatch (1), more preferably less than 3% by mass, even more preferably less than 1% by mass, even more preferably less than 0.5% by mass, and even more preferably less than 0.1% by mass. As a lower limit, it is 0% by mass.

[0108] <Particles (2)>

[0109] Particles (2) contain melt volumetric velocity (MVR) of 0.1~4 cm⁻¹ measured according to ISO 1133 at 190°C and with a load of 2.16 kg. 3Polyacetal resin (C) with a score of less than 10.

[0110] In this embodiment, formaldehyde scavenger (B) can be pre-mastered using low-viscosity polyacetal resin (A), so high-viscosity polyacetal resin (C) can be suitably used as a component of the particulate blend.

[0111] The preferred MVR size is 3.5cm. 3 / 10 points or less, and preferably 0.5cm 3 / 10 points or more, preferably 1cm 3 / 10 points or above, further optimized to 1.5cm 3 / 10 points or higher, with 2cm being an even better option 3 / 10 points or above, further optimized to 2.5cm 3 / 10 points or above. By setting it below the aforementioned upper limit, there is a tendency to further improve the formaldehyde capture effect generated in the molding of high-viscosity polyacetals, which is not achievable in conventional composites. Furthermore, by setting it above the aforementioned lower limit, there is a tendency to further improve the formaldehyde capture effect of this method within the range of moldable processing.

[0112] The particles (2) in this embodiment may contain only one type of polyacetal resin (C), or they may contain two or more types. In the case of containing two or more types, the MVR of the mixture is preferably within the range described above.

[0113] As long as the above MVR is met, the type of polyacetal resin (C) is not particularly limited. It can be a homopolymer containing only divalent oxymethylene as a structural unit, or a copolymer containing divalent oxymethylene and divalent oxyalkylene with 2 or more carbon atoms as structural units.

[0114] Examples of oxoalkylene groups having 2 or more carbon atoms include oxoethylene, oxopropylene, and oxobutylene.

[0115] In polyacetal resin (C), the proportion of oxoalkylene groups having 2 or more carbon atoms in the total molar number of oxomethyl groups and oxoalkylene groups having 2 or more carbon atoms is not particularly limited, and for example, it can be 0.5 to 10 mol%. The number of carbon atoms in the oxoalkylene groups can be 2 or more, preferably 6 or less, and more preferably 4 or less.

[0116] To manufacture the aforementioned polyacetal resin (C), trialkylene is typically used as the main raw material. Furthermore, to introduce alkylene groups with 2 to 6 carbon atoms into the polyacetal resin (C), cyclic methylal or cyclic ethers can be used, for example. Specific examples of cyclic methylal include 1,3-dioxolane, 1,3-dialkylene, 1,3-dioxane, 1,3-dioxane, 1,3-dioxane, 1,3,5-trioxane, and 1,3,6-trioxane. Specific examples of cyclic ethers include ethylene oxide, propylene oxide, and butane oxide. To introduce ethylene into the polyacetal resin (C), 1,3-dioxolane can be used, for example; to introduce propylene oxide, 1,3-dialkylene can be used; and to introduce butylene, 1,3-dioxane can be used.

[0117] It should be noted that in polyacetal resin (C), the amount of hemiacetal terminal groups, formyl terminal groups, and terminal groups that are unstable to heat, acid, and alkali are preferred. Here, hemiacetal terminal groups refer to the group represented by -OCH2OH, and formyl terminal groups refer to the group represented by -CHO.

[0118] In this embodiment, the content of polyacetal resin (C) in the particles (2) is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 97% by mass or more, and even more preferably 99% by mass or more. Alternatively, it can be 100% by mass or less.

[0119] The particles (2) in this embodiment may contain only one type of polyacetal resin (C), or they may contain two or more types. When two or more types are contained, the total amount is preferably within the range described above.

[0120] The particles (2) in this embodiment may contain other components besides polyacetal resin (C), or they may not contain any.

[0121] Other components include compounds containing functional groups (such as melamine compounds), heat stabilizers, antioxidants, weather stabilizers, light stabilizers, ultraviolet absorbers, release agents, lubricants, nucleating agents, antistatic agents, antibacterial agents, and colorants (pigments, dyes). They can be used alone or in combination of two or more.

[0122] The content of these other components is preferably less than 5% by mass of the particles (2), more preferably less than 3% by mass, even more preferably less than 1% by mass, even more preferably less than 0.5% by mass, and even more preferably less than 0.1% by mass. As a lower limit, it is 0% by mass.

[0123] The particles (2) in this embodiment may contain formaldehyde scavenger (B), but it is preferable that they do not contain it substantially. "Substantially not containing" means that the content of formaldehyde scavenger (B) in the particles (2) in this embodiment is preferably less than 0.5% by mass, more preferably less than 0.3% by mass, even more preferably less than 0.1% by mass, even more preferably less than 0.05% by mass, even more preferably less than 0.01% by mass, and particularly preferably less than 0.001% by mass. As a lower limit, it is 0% by mass.

[0124] <Incorporation of particulate admixtures>

[0125] In the particulate blend of this embodiment, 3 to 25 parts by mass of masterbatch (1) are included relative to 100 parts by mass of the above-mentioned particles (2).

[0126] Relative to 100 parts by weight of particles (2), the content of masterbatch (1) in the particle blend of this embodiment is preferably 4 parts by weight or more, more preferably 6 parts by weight or more, further preferably 8 parts by weight or more, even more preferably 11 parts by weight or more, even more preferably 15 parts by weight or more, and preferably 22 parts by weight or less. By setting it to the lower limit or above, it can exhibit formaldehyde capture effect as a masterbatch. In addition, by setting it to the upper limit or below, there is a tendency to suppress mold contamination and further improve the formaldehyde capture effect.

[0127] The particulate blend of this embodiment may contain only one type of masterbatch (1) and / or one type of particle (2), or it may contain two or more types. When the particulate blend of this embodiment contains two or more types of masterbatch (1) and / or particles (2), the total amount is preferably within the range described above.

[0128] The particulate blend of this embodiment can generally be manufactured by dry blending of masterbatch (1) and particles (2).

[0129] The particulate blend of this embodiment may further include a second masterbatch. Examples of the second masterbatch include materials obtained by mastering resin additives other than formaldehyde scavengers, such as pigments and flame retardants.

[0130] Furthermore, the particulate blend of this embodiment may substantially consist only of masterbatch (1) and particles (2). "Substantially" means, for example, that the total mass of masterbatch (1) and particles (2) in the particulate blend is 90% or more by mass of the total mass of the particulate blend, preferably 95% or more by mass, more preferably 97% or more by mass, and even more preferably 99% or more by mass. The upper limit is 100% by mass.

[0131] <Method for manufacturing resin composition>

[0132] The method for manufacturing the resin composition of this embodiment is characterized by comprising: measuring a melt volumetric velocity (MVR) of 0.1 to 4 cm⁻¹ under conditions of 190°C and a load of 2.16 kg according to ISO 1133. 3 Polyacetal resin (C) of less than 10% is melt-blended with masterbatch (1), wherein the melt volumetric velocity (MVR) of the masterbatch (1) is 5 to 50 cm³ / h relative to the conditions measured according to ISO 1133 at 190°C and a load of 2.16 kg. 3 100 parts by weight of polyacetal resin (A) containing 0.5 to 3.0 parts by weight of formaldehyde scavenger (B).

[0133] The above-mentioned masterbatch (1) has the same meaning as the above-mentioned masterbatch (1).

[0134] In addition, polyacetal resin (C) was exemplified using the aforementioned particles (2) as an example, and the preferred range is also the same.

[0135] More specifically, examples include methods of feeding masterbatch (1) and polyacetal resin (C) to an extruder, performing melt mixing, and obtaining a granular composition; and methods of directly molding masterbatch (1) and polyacetal resin (C).

[0136] The resin composition of this embodiment contains particles and is a molded article obtained by molding processing such as injection molding.

[0137] <Molded Products>

[0138] Next, the particulate blend of this embodiment and the molded article formed from the above-described resin composition will be described. The molded article of this embodiment can significantly suppress the generation of formaldehyde.

[0139] The resin composition of this embodiment can be molded by known molding methods such as injection molding, extrusion molding, compression molding, blow molding, and vacuum molding.

[0140] The particulate blends, masterbatches, resin compositions, and molded articles of this embodiment can be suitably used in applications where there is a strong requirement to reduce formaldehyde emissions, such as automotive parts, electrical / electronic parts, precision machinery parts, building materials / piping parts, daily necessities, cosmetic parts, and medical equipment parts.

[0141] More specifically, examples of automotive components include: interior handles, fuel tank openers, seat belt buckles, auxiliary belts, various switches, handles, levers, buckles, and other interior components; electrical system components such as instruments and connectors; vehicle electrical / electronic components such as audio equipment and car navigation equipment; metal-contact components such as the window regulator's support plate; door lock actuator components; mirror components; wiper motor system components; and fuel system components.

[0142] As electrical / electronic components, examples include constituent parts or components of devices with multiple metal contact points, such as audio equipment like cassette recorders and CD / DVD players, video equipment like VTRs, 8mm cameras, and digital cameras, and components or components of office automation (OA) equipment like copiers, fax machines, word processors, and computers. Specific examples of these constituent parts or components include chassis, gears, joysticks, cams, pulleys, and bearings. Furthermore, they can also be used for optical and magnetic media components where at least a portion is formed from molded parts, such as components for music cassette metal tapes, digital cassette audio tapes, 8mm cassette video tapes, digital cassette video tapes, floppy disks, mini-cassette disks, and DVD cassette disks.

[0143] Furthermore, the molded articles of this embodiment can be suitably used in a wide range of everyday / cosmetic / medical related components, such as lighting fixtures, accessories, piping, valves, faucets, toilet peripheral equipment components, fasteners, stationery, lipstick / lip gloss containers, cleaners, water purifiers, spray nozzles, spray containers, aerosol containers, general containers, and needle holders.

[0144] Example

[0145] The present invention will be described in more detail below with examples. The materials, amounts, proportions, processing contents, processing order, etc., shown in the following examples can be appropriately changed without departing from the spirit of the invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0146] If the measuring equipment used in the embodiments is difficult to obtain due to production stoppages or other reasons, other equipment with equivalent performance can be used for measurement.

[0147] The present invention will be described in more detail below with examples. The materials, amounts, proportions, processing contents, processing order, etc., shown in the following examples may be appropriately changed without departing from the spirit of the invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0148] If the measuring equipment used in the embodiments is difficult to obtain due to production stoppages or other reasons, other equipment with equivalent performance can be used for measurement.

[0149] 1. Raw materials

[0150] (A) Polyacetal resin

[0151] Polyacetal resin (MVR: 9cm) 3 (10 points): Manufactured by Linghuanhua Polyoxymethylene Co., Ltd., Lupital F20-05

[0152] Polyacetal resin (MVR: 27cm) 3 (10 points): Manufactured by Linghuanhua Polyoxymethylene Co., Ltd., Lupital F30-05

[0153] Polyacetal resin (MVR: 3cm) 3 (10 points): Manufactured by Linghuanhua Polyoxymethylene Co., Ltd., Lupital F10-EW

[0154] The MVR was measured according to ISO 1133 at 190°C and with a load of 2.16 kg. The unit is cm. 3 / 10 points.

[0155] (B) Formaldehyde scavenger

[0156] Adipic acid dihydrazide: Manufactured by Japan Finechem Co., Ltd., Product No.: ADH

[0157] 1,12-Dodecanoic acid dihydrazide: Manufactured by Japan Finechem Co., Ltd., Product No.: N-12

[0158] Ethylurea: manufactured by HUBEI KANG ZHUANG ENVIRONMENT TECHNOLOGY (2-imidazolinone)

[0159] 2. Preparation of Masterbatch (MB-1~MB-5)

[0160] According to the mixing ratio shown in Table 1 (all parts by mass in Table 1), polyacetal resin and formaldehyde scavenger were uniformly mixed using a high-speed mixer manufactured by Kawada Manufacturing Co., Ltd. Then, the mixture was melt-mixed using a twin-screw extruder (PCM-30 manufactured by Ikegai Iron Works Co., Ltd., screw diameter 30mm) at a screw speed of 120rpm and a cylinder set temperature of 190°C. The mixture was then extruded into wire and cut by a granulator to produce masterbatches MB-1 to MB-5.

[0161]

[0162] Examples 1-8, Comparative Examples 1-5

[0163] According to the mixing ratio shown in Table 2 or Table 3 (Table 2 and Table 3 are expressed in parts by mass), polyacetal resin (granules) and the masterbatch (MB-1~MB-5) or unmastered formaldehyde scavenger are uniformly mixed using a high-speed mixer manufactured by Kawada Manufacturing Co., Ltd. Then, the mixture is melt-mixed using a twin-screw extruder (PCM-30 manufactured by Ikegai Iron Works Co., Ltd., screw diameter 30mm) at a screw speed of 120rpm and a cylinder set temperature of 190°C. The mixture is then extruded into a wire and cut by a granulator to produce granules (resin composition).

[0164] <Determination of Formaldehyde Production>

[0165] Using the particles obtained above, a 100mm×40mm×2mm flat test piece was produced by heating the particles in a cylinder at 215°C for 1 minute using an SE-30 manufactured by Sumitomo Heavy Industries, Ltd., and then injection molding at a mold temperature of 80°C.

[0166] After the above-mentioned plate test pieces were left to stand for 24 hours in an atmosphere of 23°C and 50% relative humidity, the formaldehyde emission in 1g of polyacetal resin was determined (unit: μg / g-POM) according to the method described in the German Association of the Automotive Industry standard VDA275 (Automotive Interior Components - Quantification of Formaldehyde Emission Based on Modified Flask Method).

[0167] (i) Add 50 mL of distilled water to a polyethylene container, and with the above-mentioned plate test piece suspended in the air, cover it and heat it at 60°C for 3 hours in a sealed state.

[0168] (ii) After standing at room temperature for 60 minutes, remove the plate test piece.

[0169] (iii) The amount of formaldehyde absorbed in the distilled water in the polyethylene container was determined by using a UV spectrometer and the acetylacetone colorimetric method. The formaldehyde production amount was obtained by dividing the amount of formaldehyde by the mass of POM in the plate test piece.

[0170] <Mold Contamination>

[0171] Mold contamination was evaluated as described below.

[0172] First, using a Minimat M8 / 7A molding machine manufactured by Sumitomo Heavy Industries, Ltd., and a teardrop-shaped mold, the obtained granules were continuously molded 500 times (shots) at a molding temperature of 200°C and a mold temperature of 40°C. After molding, the condition of the inner wall surface of the mold was observed visually. The criteria related to the mold contamination suppression effect are as follows. In addition, five experts made a judgment by majority vote through visual observation.

[0173] A: There are no mold deposits, and the mold contamination suppression effect is good.

[0174] B: Unlike A above, for example, there are mold deposits, resulting in poor mold contamination suppression.

[0175]

[0176]

[0177] Based on the above results, it is clear that the particulate admixture of this embodiment has a high formaldehyde capture effect and less mold contamination (Examples 1-8).

[0178] In contrast, when a high-viscosity polyacetal resin was used as the masterbatch (Comparative Example 1), the amount of formaldehyde generated was comparable to that in the case without a formaldehyde scavenger (Comparative Example 2). Furthermore, in cases where the formaldehyde scavenger was not mastered and directly incorporated into the high-viscosity polyacetal resin (Comparative Examples 3 and 4), formaldehyde was not captured. On the other hand, in Comparative Examples 3 and 4, when the content of the formaldehyde scavenger was increased (Comparative Example 5), formaldehyde generation was suppressed, but mold contamination was significant.

Claims

1. A granule blend comprising a master batch (1) and a granule (2), In the masterbatch (1), the melt volume rate (MVR) measured according to ISO 1133 at 190°C under a load of 2.16 kg is 5 to 50 cm3 / 10 min 3 / 10 parts of a polyacetal resin (A) 100 parts, containing 0.5 to 3.0 parts by mass of a formaldehyde scavenger (B), The particles (2) have a melt volume rate (MVR) of 0.1 to 4 cm 3 a polyacetal resin (C) having a molecular weight of 10,000 or less.

2. The granule blend according to claim 1, wherein, 3-25 parts by mass of the master batch (1) are contained relative to 100 parts by mass of the granule (2).

3. The granule blend according to claim 1 or 2, wherein, the formaldehyde trapping agent (B) contains at least one selected from the group consisting of a hydrazine compound, a hydrazone body of a hydrazine compound, a guanamine compound, and a urea compound.

4. A master batch, wherein, a melt volume rate (MVR) of 5 to 50 cm3 / 10 min measured according to ISO 1133 at 190°C under a load of 2.16 kg 3 / 10 min, 100 parts by mass of a polyacetal resin (A), and 0.5 to 3.0 parts by mass of a formaldehyde scavenger (B).

5. The master batch according to claim 4, wherein, the formaldehyde trapping agent (B) contains at least one selected from the group consisting of a hydrazine compound, a hydrazone body of a hydrazine compound, a guanamine compound, and a urea compound.

6. A method for producing a resin composition, the method comprising: The melt volume rate (MVR) measured according to ISO 1133 at 190°C under a load of 2.16 kg is 0.1 to 4 cm 3 The polyacetal resin (C) having a MFR of 10 or less is melt-kneaded with the masterbatch (1), In the masterbatch (1), the melt volume rate (MVR) measured according to ISO 1133 at 190°C under a load of 2.16 kg is 5 to 50 cm3 / 10 min 3 / 10 minutes, 100 parts by mass of a polyacetal resin (A) containing 0.5 to 3.0 parts by mass of a formaldehyde scavenger (B).

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