JP2021152141A - Aldehyde scavenger - Google Patents

Abstract

To provide an aldehyde scavenger that can properly trap aldehyde.SOLUTION: The present disclosure provides an aldehyde scavenger (X) that contains a copolymer (A) containing a (meth)acrylic amide (a) and an unsaturated monomer (b) having an alkylene oxy group (with a C2-4 alkylene group) as constituent monomers; a polyacetal resin composition (Y) containing the aldehyde scavenger (X) and a polyacetal resin (D); and a molding (Z) obtained by molding the polyacetal resin composition (Y).SELECTED DRAWING: None

Description

The present invention relates to aldehyde scavengers.

Polyacetal resins are used in a wide range of applications, but for example, formaldehyde emission is an issue in automobile interior materials. To solve this problem, it has been proposed to add a dihydrazide compound as a scavenger (for example, Patent Document 1). Further, it is known that poly (meth) acrylamide is used as a heat stabilizer (for example, Patent Document 2). However, even with the techniques of Patent Documents 1 and 2, it cannot be said that the aldehyde scavenging property is sufficiently satisfactory, and the development of an aldehyde scavenger having excellent aldehyde scavenging property has been required.

International Publication No. 2005/040275 Japanese Unexamined Patent Publication No. 2012-501379

An object of the present invention is to provide an aldehyde scavenger having excellent aldehyde scavenging properties.

The present inventors have arrived at the present invention as a result of studies for achieving the above object. That is, the present invention is a copolymer (A) containing (meth) acrylamide (a) and an unsaturated monomer (b) having an alkylene (alkylene group having 2 to 4 carbon atoms) oxy group as a constituent monomer. ); The polyacetal resin composition (Y) containing the aldehyde trapping agent (X) and the polyacetal resin (D); the polyacetal resin composition (Y) is molded. It is a molded product (Z) made of plastic.

The aldehyde scavenger (X) of the present invention has the following effects.
(1) Excellent aldehyde trapping property (particularly formaldehyde trapping property).
(2) The polyacetal resin composition (Y) is excellent in moldability (mold contamination resistance).

The aldehyde scavenger (X) of the present invention contains (meth) acrylamide (a) and an unsaturated monomer (b) having an alkylene (alkylene group having 2 to 4 carbon atoms) oxy group as a constituent monomer. It contains the copolymer (A). In the present invention, the aldehyde scavenger means an agent that traps aldehydes generated by thermal decomposition of a resin having an oxyalkylene group (oxymethylene group in the case of a polyacetal resin) such as a polyacetal resin.
In the present invention, the copolymer (A) comprises an unsaturated monomer (b) having the alkylene (alkylene group having 2 to 4 carbon atoms) oxy group in addition to the (meth) acrylamide (a). By including it as a body, the compatibility with polyacetal resin and the like is improved, and since it can be uniformly dispersed in the resin, it has excellent trapping property of aldehydes (particularly formaldehyde), and it is difficult to bleed out and moldability (mold resistance) It is presumed that it is also excellent in (contamination).

<(Meta) acrylamide (a)>
Examples of the (meth) acrylamide (a) in the present invention include metaacrylamide and acrylamide.
Of the above (a1), acrylamide is preferable from the viewpoint of industrial and aldehyde trapping properties.

<Unsaturated monomer (b) having an alkylene (2-4 carbon atoms of the alkylene group) oxy group>
The unsaturated monomer (b) in the present invention is an unsaturated monomer having an alkylene (alkylene group having 2 to 4 carbon atoms) oxy group, and is preferably (from the viewpoint of dispersibility in a polyacetal resin or the like). Meta) A compound having one unsaturated group capable of reacting with acrylamide (a) (monofunctional unsaturated monomer).

Examples of the alkyleneoxy group [hereinafter, may be abbreviated as AO] contained in (b) include an ethyleneoxy group (-CH ₂ CH ₂ O-) and a propyleneoxy group (-CH ₂ C (CH ₃ ) O]. -Or-CH _{2 CH 2} CH ₂ O-), butyleneoxy group and the like can be mentioned.
Among the above alkyleneoxy groups, from the viewpoint of dispersibility in a polyacetal resin or the like, ethyleneoxy groups and propyleneoxy groups are preferable, their combined use is preferable, and ethyleneoxy groups are more preferable.
Further, the alkyleneoxy group contained in (b) may be, for example, one or two or more (polyalkyleneoxy group), but from the viewpoint of dispersibility in a polyacetal resin or the like, an alkyleneoxy group is preferably used. It is a poly (3 to 100) alkyleneoxy group having 3 to 100 pieces.
Further, in (b) contained in the copolymer (A), the average number of moles of AO added per molecule (b) is preferably 1 to 300, more preferably 3 to 100. The average number of moles added is not always an integer, but may be a decimal number.

Examples of the unsaturated group contained in (b) include a (meth) acryloyl group, an N- (meth) acrylamide group, and a (meth) allyl group.
Of the unsaturated groups, the (meth) acryloyl group is preferable from the viewpoint of industriality and moldability.
For example, the (meth) acryloyl group means a metaacrylloyl group and / or an acryloyl group, and the N- (meth) acrylamide group means an N-methacrylamide group and / or an N-acrylamide group, and (meth). ) Acryloyl group means methallyl group and / or allyl group.

Specific examples of the unsaturated monomer (b) include a monomer (b1) represented by the following general formula (1) and a monomer (b2) represented by the following general formula (2). Can be mentioned.

[In the formula (1), R ¹ and R ² are independently hydrogen atoms or methyl groups; m is 0 or 1; AO is an oxyalkylene group having 2 to 4 carbon atoms; n is 1 to 300, from the viewpoint of moldability. Therefore, preferably 3 to 100; n AOs when n is 2 or more may be the same or different. R ³ is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. ]

[In the formula (2), R ⁴ is a hydrogen atom or a methyl group; AO is an oxyalkylene group having 2 to 4 carbon atoms; p is 1 to 300, preferably 3 to 100 from the viewpoint of moldability, and p is 2 or more. The p AOs in the case may be the same or different. R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. ]

In the general formulas (1) and (2), the AO includes, for example, an ethyleneoxy group (-CH ₂ CH ₂ O-), a propyleneoxy group (-CH ₂ C (CH ₃ ) O- or -CH ₂ CH _2). CH ₂ O−), butyleneoxy group and the like can be mentioned.
The AO is preferably an ethyleneoxy group, a propyleneoxy group, a combination thereof, and more preferably an ethyleneoxy group from the viewpoint of dispersibility in a polyacetal resin or the like.

N in the general formula (1) and p in the general formula (2) represent the average number of moles of AO added per molecule of the monomer (b1) or (b2), and are not necessarily integers. However, it may be a decimal number. When two or more kinds of alkyleneoxy groups are contained in AO, each alkyleneoxy group may be added in a block shape or a random shape. "Block-like" refers to a mode in which two or more alkyleneoxy groups of one type are continuous.

In R ^{3 in} the general formula (1) and R ⁵ in the general formula (2), the hydrocarbon group having 1 to 30 carbon atoms is a methyl group, an ethyl group, or a linear saturated alkyl having 3 to 30 carbon atoms. Group {for example, n-propyl group, n-octyl group, lauryl group, stearyl group, behenyl group, 1-triacontyl group, etc.}, linear unsaturated alkyl group having 3 to 30 carbon atoms {for example, oleyl group, eleidyl group Etc.}, branched alkyl groups with 3 to 30 carbon atoms {eg, isopropyl group, 2-ethylhexyl group, isostearyl group, etc.}, hydrocarbon groups with an alicyclic skeleton of 3 to 30 carbon atoms {eg, cyclopropyl group, etc. Cyclohexyl groups, etc.}, aromatic groups having 6 to 30 carbon atoms {for example, phenyl groups, naphthyl groups, etc.}, aromatic aliphatic groups having 7 to 30 carbon atoms {for example, benzyl groups, etc.} and the like can be mentioned.
Among the above-mentioned hydrocarbon groups having 1 to 30 carbon atoms, a hydrocarbon group having 1 to 12 carbon atoms is preferable, and a methyl group is more preferable, from the viewpoint of industriality and moldability.
As R ³ and R ⁵ , hydrogen atoms and hydrocarbon groups having 1 to 20 carbon atoms are preferable, and hydrogen atoms and hydrocarbon groups having 1 to 12 carbon atoms are more preferable, from the viewpoint of dispersibility in polyacetal resins and the like. be. As R ³ and R ⁵ , if the number of carbon atoms is small, the ratio of the primary amide group and AO in the copolymer (A) is high, and the dispersibility in the polyacetal resin and the like and the aldehyde trapping property tend to be high.

As the unsaturated monomer (b), the monomers (b1) and (b2) are preferable, and polyalkylene (alkylene group having 2 to 4 carbon atoms) is more preferable, from the viewpoint of dispersibility in a polyacetal resin or the like. Glycol mono (meth) acrylate, alkoxy (alkoxy group carbon number 1-12) polyalkylene (alkylene group carbon number 2-4) glycol mono (meth) acrylate, polyalkylene (alkylene group carbon number 2-4) glycol It is at least one selected from the group consisting of mono (meth) acrylamide and alkoxy (alkoxy group having 1 to 12 carbon atoms) polyalkylene (alkylene group having 2 to 4 carbon atoms) glycol mono (meth) acrylamide, and is particularly preferable. Consists of polyalkylene (2-4 carbon atoms of alkylene group) glycol mono (meth) acrylate and alkoxy (1-12 carbon atoms of alkoxy group) polyalkylene (2-4 carbon atoms of alkylene group) glycol mono (meth) acrylate At least one selected from the group, most preferably alkoxy (alkoxy group having 1 to 12 carbon atoms) polyalkylene (alkylene group having 2 to 4 carbon atoms) glycol mono (meth) acrylate.

The molecular formula weight or weight average molecular weight of the unsaturated monomer (b) (hereinafter abbreviated as Mw. The measurement is performed by the gel permeation chromatography (GPC) method described later) is based on the viewpoint of dispersibility in a polyacetal resin or the like. Therefore, it is preferably 250 to 17,000, and more preferably 350 to 10000.

<Copolymer (A)>
The copolymer (A) in the present invention contains (meth) acrylamide (a) and an unsaturated monomer (b) having an alkylene (alkylene group having 2 to 4 carbon atoms) oxy group as a constituent monomer. ..
The weight ratio [(a) / (b)] of the (meth) acrylamide (a) to the unsaturated monomer (b) in the monomer constituting the copolymer (A) is determined by the aldehyde trapping property and the aldehyde trapping property. From the viewpoint of moldability, it is preferably 20/80 to 95/5, more preferably 30/70 to 90/10, and particularly preferably 40/60 to 85/15.

The copolymer (A) contains, for example, other monomers (c) as constituent monomers in addition to the above (a) and (b) in order to improve moldability and aldehyde trapping performance. It may be.
In that case, based on the total weight of (a) and (b), the weight of (c) is preferably 25% by weight or less, more preferably 15% by weight or less, and particularly preferably 10% by weight or less.

Based on the weight of the copolymer (A), the weight ratio of AO units in (A) is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, from the viewpoint of dispersibility in a polyacetal resin or the like. %.
Based on the weight of the copolymer (A), _{the weight ratio of the primary amide group (-CONH 2} ) in (A) is preferably 10 to 70% by weight, more preferably 15 from the viewpoint of aldehyde trapping property. ~ 60% by weight.
The weight ratio (AO unit / primary amide group) of the weight of the AO unit in (A) to the weight of the primary amide group (-CONH ₂ ) is 0.05 to 0.05 from the viewpoint of aldehyde trapping property and moldability. 6 is preferable, and more preferably 0.08 to 5.5.

Examples of the other monomer (c) include alkyl (alkyl having 1 to 20 carbon atoms, preferably 2 to 12) esters of (meth) acrylate [for example, methyl (meth) acrylate, (meth) acrylate. Ethyl, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, etc.], vinyl acetate, single amount having a carboxyl group Body {for example, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, vinyl benzoic acid, vinyl acetic acid, etc.}, monomer having a sulfonic acid group {for example, vinyl sulfonic acid, allyl sulfonic acid, metallic sulfone Acid, alkyl (1 to 23 carbon atoms) allyl sulfosuccinic acid, 2-acrylamide-2-methylpropane sulfonic acid, 4-vinylbenzene sulfonic acid, dodecenebenzene sulfonic acid, sulfoalkyl (meth) acrylate, etc.}, phosphate group (For example, vinyl phosphonic acid, diethyl vinyl phosphonate, phenyl vinyl phosphonic acid, etc.}, monomer having an isocyanate group {for example, 2-isocyanatoethyl (meth) acrylate, etc.}, simple having a glycidyl group. Quantities {for example, glycidyl (meth) acrylate and the like}, (meth) acrylonitrile and the like can be mentioned.

As the unsaturated monomer (c), from the viewpoint of aldehyde trapping property, a monomer having a carboxyl group, a monomer having a sulfonic acid group, and a monomer having a phosphoric acid group are preferable, and a carboxyl group is more preferable. It is a monomer having a group, and is particularly preferably (meth) acrylic acid.

From the viewpoint of aldehyde trapping property, (A) preferably has an acidic group (for example, a carboxyl group, a sulfonic acid group, a phosphoric acid group, etc.). As a method for assuming that (A) has an acidic group, at least selected from the group consisting of the above-mentioned monomer having a carboxyl group, the monomer having a sulfonic acid group, and the monomer having a phosphoric acid group. One kind of monomer may be used as a monomer component for copolymerization, or a polymerization initiator having an acidic group or a chain transfer agent may be used for introduction into (A).
Examples of the polymerization initiator having an acidic group include a peroxide initiator {for example, peroxide disuccinate}, an azo-based initiator {for example, 4,4'-azobis (4-cyanovaleric acid), and 2,2'-azobis [N. -(2-carboxyethyl) -2-methylpropion amidine] tetrahydrate, etc.} and the like.
Examples of the chain transfer agent having an acidic group include mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 4-mercaptobenzoic acid, 3-mercaptopyrubic acid, L-cysteine and the like.

When (A) has an acidic group, the amount of the acidic group is represented by the acid value (unit: mgKOH / g) of (A), preferably 2 to 160, more preferably 10 to 100, and particularly preferably 20 to. It is 80. When the acid value is 2 or more, the aldehyde capture property tends to be further good, and when the acid value is 160 or less, the moldability tends to be good.
The acid value of (A) can be measured according to JIS K 0070.

Weight average molecular weight of (A) [hereinafter abbreviated as Mw. The measurement is performed by the gel permeation chromatography (GPC) method described later. ] Is preferably 5,000 to 1,000,000, more preferably 7,000 to 300,000, and particularly preferably 8,000 to 100,000 from the viewpoint of aldehyde trapping property and moldability.

The GPC measurement conditions for the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present invention are as follows.
<GPC measurement conditions>
[1] Equipment: Gel permeation chromatography
[Model number "HLC-8120GPC", manufactured by Tosoh Corporation]
[2] Column: "TSKgelG6000PWxl", "TSKgel"
"G3000PWxl" [both manufactured by Tosoh Corporation] are connected in series.
[3] Eluent: Methanol / water = 30/70 (volume ratio)
Dissolved 0.5% by weight sodium acetate.
[4] Reference substance: Polyethylene glycol (hereinafter abbreviated as PEG)
[5] Injection conditions: sample concentration 0.25% by weight, column temperature 40 ° C.

The copolymer (A) is an unsaturated monomer (b) having (1) (meth) acrylamide (a) and an alkylene (alkylene group having 2 to 4 carbon atoms) oxy group, and if necessary, other single amounts. A method of polymerizing a monomer component containing the body (c) by a known polymerization method, for example, a solution polymerization method, (2) (meth) acrylamide (a), and a carboxyl group as a precursor of (b). The carboxyl group of the copolymer (S1) obtained by polymerizing a monomer component containing the monomer (c) and, if necessary, another monomer (c) by a known polymerization method (for example, a solution polymerization method), A method for esterifying (poly) alkylene (2-4 carbon atoms of an alkylene group) glycol and / or monoalkoxy (poly) alkylene (2-4 carbon atoms of an alkylene group) glycol, (3) (meth) acrylamide (a). ), A monomer having an isocyanate group as a precursor of (b), and if necessary, a monomer component containing another monomer (c) is polymerized by a known polymerization method (for example, a solution polymerization method). Urethane (poly) alkylene (2-4 carbon atoms of alkylene group) glycol and / or monoalkoxy (poly) alkylene (2-4 carbon atoms of alkylene group) glycol is added to the isocyanate group of the copolymer (S2). Method for Polymerization, (4) A monomer component containing (meth) acrylamide (a), a monomer having a glycidyl group as a precursor of (b), and, if necessary, another monomer (c). In addition to the glycidyl group of the copolymer (S3) polymerized by a known polymerization method (for example, solution polymerization method), (poly) alkylene (2-4 carbon atoms of the alkylene group) glycol and / or monoalkoxy (poly) alkylene It can be produced by a method of adding glycol (2 to 4 carbon atoms of an alkylene group).
In (1) to (4), a solution polymerization method performed in a solvent (water and / or an organic solvent) is preferable from the viewpoint of productivity.
In (1), for example, a method of carrying out a polymerization reaction of a monomer component containing (a) and (b) in a solvent from a polymerization initiator in the presence of a chain transfer agent, etc. Can be mentioned.
As for the content of water, it is preferable to use 30% by weight or more of water with respect to the total amount of the solvent used.
Organic solvents that can be used alone or with water include aqueous solvents (soluble in water at 25 ° C. of 10 g or more / 100 g of water), such as ketones (acetone, methyl ethyl ketone (hereinafter abbreviated as MEK), diethyl ketone, etc.). Examples thereof include alcohols (methanol, ethanol, isopropanol, etc.), and acetone, MEK, isopropanol, etc. are preferable from the viewpoint of productivity. The organic solvent can be used alone or in combination of two or more.
The (A) and (S) (S1 to S3 above) are preferably obtained as a solution of (A) or a solution of (S), and the content of (A) and (S) in the solution is productivity. From the viewpoint of handleability in the post-process, it is preferably 5 to 80% by weight, more preferably 10 to 70% by weight, and particularly preferably 20 to 60% by weight.

The polymerization temperature during the production of (A) and (S) is preferably 0 to 200 ° C., more preferably 40 to 150 ° C. from the viewpoint of productivity and molecular weight control of (A) and (S).
The polymerization time is preferably 1 to 10 hours, more preferably 2 to 8 hours from the viewpoint of reducing the residual monomer content in the product and productivity.
The end point of the polymerization reaction can be confirmed by the amount of residual monomer. The amount of residual monomer is preferably 5% by weight or less, more preferably 3% by weight or less, based on the weight of (A), from the viewpoint of mechanical strength and moldability of the molded product. The amount of residual monomer can be measured by a gas chromatography method.

<Aldehyde scavenger (X)>
The aldehyde scavenger (X) of the present invention contains the copolymer (A), and in addition to the copolymer (A), a solvent or a polymerization initiator used in the production of (A) is started. It may contain an agent, a chain transfer agent, a residual monomer and the like.
The (X) is preferably obtained by desolving the solution of the above (A). The weight of the solvent in (X) is preferably 20% by weight or less, more preferably 0.01 to 5% by weight, based on the weight of (X).
The content of (A) in (X) is preferably 80% by weight or more, more preferably 95% by weight or more, based on the weight of (X), from the viewpoint of aldehyde trapping property and moldability. ..
The aldehyde scavenger (X) of the present invention can be used as various aldehyde scavengers, and in particular, it can be suitably used as an aldehyde scavenger for the polyacetal resin (D) described later.

<Polyacetal resin composition (Y)>
The polyacetal resin composition (Y) of the present invention contains the aldehyde scavenger (X) and the polyacetal resin (D) described later.
The weight ratio [(X) / (D)] of (X) to (D) is preferably 0.05 / 99.95 to 5/95, more preferably 0.05 / 99.95 to 5/95, from the viewpoint of aldehyde trapping property and mechanical strength. Is 0.1 / 99.9 to 4/96, particularly preferably 0.2 / 99.8 to 2/98.
The weight ratio [(A) / (D)] of (A) to (D) is preferably 0.05 / 99.95 to 5/95, more preferably 0.05 / 99.95 to 5/95, from the viewpoint of aldehyde trapping property and mechanical strength. Is 0.1 / 99.9 to 4/96, particularly preferably 0.2 / 99.8 to 2/98.
The weight ratio of the AO unit derived from the above (A) in (Y) is preferably 0.0025 to 1.5% by weight based on the weight of (Y) from the viewpoint of aldehyde trapping property and mechanical strength. , More preferably 0.005 to 1.0% by weight, and particularly preferably 0.01 to 0.8% by weight.
_{The weight ratio of the primary amide group (-CONH 2} ) derived from the above (A) in (Y) is preferably 0, based on the weight of (Y) from the viewpoint of aldehyde trapping property and mechanical strength. It is 0025 to 2.0% by weight, more preferably 0.01 to 1.5% by weight, and particularly preferably 0.02 to 1.3% by weight.

The polyacetal resin composition (Y) contains an aldehyde scavenger (X), a polyacetal resin (D), and if necessary, another resin additive (C) [for example, an antioxidant, a compatibilizer (ethylene oxide 2 of bisphenol A). ~ 4 mol adduct, etc.)] is obtained by, for example, melt-kneading.

<Polyacetal resin (D)>
Examples of the polyacetal resin (D) in the present invention include known polymers containing oxymethylene and, if necessary, oxyethylene as a unit structure.
Examples of the commercially available product of (D) include Delrin [registered trademark, manufactured by DuPont] and Duracon [registered trademark, manufactured by Polyplastics Co., Ltd.].

<Molded product (Z)>
The molded product (Z) of the present invention is obtained by molding the polyacetal resin composition (Y). Examples of the molding method include injection molding, compression molding, calender molding, slush molding, rotary molding, extrusion molding, blow molding, film molding (casting method, tenter method, inflation method, etc.) and the like.

The aldehyde scavenger (X) of the present invention is excellent in aldehyde scavenging property. Further, the polyacetal resin composition (Y) is excellent in mold contamination during molding. Further, the molded product (Z) releases a small amount of aldehyde.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In the following, "part" indicates a part by weight.

The compositions, symbols, etc. of the raw materials used in Examples and Comparative Examples are as follows.
<(Meta) acrylamide (a)>
Aqueous solution of (a1-1):
40% by weight aqueous solution of acrylamide (a1-1) [manufactured by Mitsui Chemicals, Inc.]

<Monomer having an alkyleneoxy group (b)>
(B1-1):
Polyethylene glycol monoacrylate (average number of moles of alkyleneoxy group added: 4.5) [manufactured by NOF CORPORATION, Blemmer AE-200, chemical formula = 270]
(B1-2):
Methoxypolyethylene glycol monoacrylate (average number of moles of alkyleneoxy group added: 9) [manufactured by NOF CORPORATION, Blemmer AME-400, chemical formula amount = 482]
(B1-3):
Methoxypolyethylene glycol methacrylate (average number of moles of alkyleneoxy group added: 90) [NOF Corporation Blemmer PME-4000, chemical formula = 4060]
(B1-4):
Polypropylene glycol monoacrylate (average number of moles of alkyleneoxy group added: 3.5) [manufactured by NOF CORPORATION, Blemmer AP-200, chemical formula = 275]
(B1-5):
Lauroxypolyethylene glycol methacrylate (average number of moles of alkyleneoxy group added: 4) [NOF Corporation Blemmer PLE-200, chemical formula = 430]
(B2-1):
Methoxypolyethylene glycol acrylamide (average number of moles of alkyleneoxy group added: 15) [Biochempeg Scientific Inc. Manufactured by MPEG-ACA, chemical formula = 733]
(C1-1): Acrylic acid

<Polyacetal resin (D)>
(D-1):
Product name "Duracon M90-44 (standard grade)", made by Polyplastics Co., Ltd.

<Example 1>
237.5 parts of a 40 wt% aqueous solution of acrylamide (a1-1) [(a1-1) [pure content] 95.0 parts], methoxypolyethylene glycol methacrylate (number of moles of ethylene oxide added: 90) (b1-3) 5. A mixed solution of 0 part and 16.7 parts of isopropyl alcohol (IPA) was adjusted at room temperature to obtain a monomer solution.
Separately, 1.0 part of azobisisobutyronitrile (AIBN) was uniformly dissolved in 50 parts of IPA at room temperature to obtain an initiator solution.
50 parts of IPA was placed in a glass reaction vessel equipped with a dropping port for the monomer solution and the initiator solution, a reflux tube and a stirring blade, and the temperature was raised to 82 ° C. while stirring at a rotation speed of 200 rpm to bring the mixture into a reflux state.
While maintaining the reflux state, all of the above-mentioned monomer solution and initiator solution were added under normal pressure over 60 minutes, and stirring was continued under normal pressure reflux for 180 minutes after the addition to carry out a polymerization reaction.
After the polymerization, the contents were transferred to an eggplant flask, and de-IPA was carried out at 60 ° C. using an evaporator until the odor of IPA disappeared. The entire amount of the eggplant flask residue is transferred to a stainless steel vat and dried for about 6 hours while appropriately mixing with a spatula in a 100 ° C. circulation dryer to contain 98.2% by weight of the copolymer (A-1). An aldehyde scavenger (X-1) was obtained. In this and the following, the content of the copolymer (A) in (X) is before (X ₁ ) and after (X 1) when (X) is dried in a circulation dryer (130 ° C., 90 minutes). _The content rate (X ₂ / X ₁ × 100) was calculated using the weight of 2).

<Examples 2-5, 7-13>
In Example 1, according to the raw material composition (part) of Table 1, (a), (b), (c), mercaptopropionic acid as a chain transfer agent, 2,2'-azobis (2-methylbutyro) as an initiator. Each copolymer (A-2) to (A-5) and (A-7) to (A-13) are contained in the same manner as in Example 1 except that nitrile (V-59) is used. The resulting aldehyde scavengers (X-2) to (X-5) and (X-7) to (X-13) were obtained.

<Example 6>
200 parts of ion-exchanged water, 51.7 parts of (a1-1), 79.2 parts of (b1-2), 2,2'-azobis (2) in a test tube (reaction vessel) equipped with a nitrogen bubbling tube and an exhaust port. After charging 10 parts of a 1 wt% aqueous solution of −methylpropionamidine) dihydrochloride (V-50), the mixture was stirred and made uniform.
At room temperature, nitrogen was aerated at 1 L / min for 5 minutes, soaked in a water bath at 50 ° C., aerated with nitrogen for another 1 minute, sealed, and polymerized at 50 ° C. for 10 hours.
After polymerization, the contents are taken out from a test tube into a petri dish, dried at 50 ° C. for 10 hours while appropriately cutting with scissors, pulverized using a tabletop mill, and containing 97.3% by weight of the copolymer (A-6). An aldehyde scavenger (X-6) was obtained.

<Comparative example 1>
Adipic acid dihydrazide [manufactured by Otsuka Chemical Co., Ltd.] was used as it was to obtain an aldehyde scavenger (ratio X-1) for comparison.

<Comparative example 2>
Add 70 parts of polyacrylamide [Sigma-Aldrich, Mn = 40,000] and 30 parts of polyethylene glycol [Sanyo Kasei Kogyo Co., Ltd., PEG-400, Mn = 400] to a beaker, stir with a spatula until uniform, and compare. An aldehyde scavenger for the above (ratio X-2) was obtained.

The results of Examples 1 to 13 and Comparative Examples 1 and 2 are shown in Table 1.

<Examples 21 to 35, Comparative examples 11 to 13>
According to the compounding composition (part) shown in Table 2, the compounding components were blended with a Henschel mixer for 3 minutes, and then melt-kneaded with a twin-screw extruder with a vent at 100 rpm, 200 ° C., and a residence time of 5 minutes. A polyacetal resin composition (Y) was obtained.
Next, each of the obtained polyacetal resin compositions (Y) was molded using an injection molding machine [“PS40E5ASE”, manufactured by Nissei Resin Industry Co., Ltd.] at a cylinder temperature of 210 ° C. and a mold temperature of 60 ° C. Each molded product (Z) was prepared and evaluated by the following performance test. The results are shown in Table 2.

(1) Formaldehyde emission amount <Evaluation of aldehyde trapping property> (VDA275 method)
In a 1 L polyethylene container, put 50 ml of distilled water and a molding test piece (100 × 40 × 3 mm) prepared by the above-mentioned injection molding machine (after preparation, stored in a plastic bag with a chuck and allowed to stand at room temperature for 24 hours). It was sealed and heated at 60 ° C. for 3 hours. Formaldehyde dissolved in distilled water was reacted with acetylacetone in the presence of ammonium ions at 60 ° C. for 10 minutes. The absorption peak at a wavelength of 412 nm was measured as the absorption peak of the reaction product by spectrophotometric method, and the amount of formaldehyde emission (ppm) per weight of the test piece was determined.

(2) Moldability (mold contamination resistance)
The above-mentioned injection molding was continuously performed for 500 shots, the surface condition of the mold was observed, and the evaluation was performed according to the following <evaluation criteria>.
<Evaluation criteria>
⊚: No deposits on the mold surface ○: Almost no deposits on the mold surface Δ: Slight deposits on the mold surface ×: Many deposits on the mold surface

From the results in Tables 1 and 2, it can be seen that the aldehyde scavenger (X) of the present invention is superior in aldehyde scavenging property and moldability (mold contamination resistance) as compared with the comparative one.

The aldehyde scavenger (X) can be used as various aldehyde scavengers because of its excellent aldehyde scavenging property, but it is particularly useful because it can be suitably used as an aldehyde scavenger for the polyacetal resin (D). be.

Claims (8)

It contains a copolymer (A) containing (meth) acrylamide (a) and an unsaturated monomer (b) having an alkylene (alkylene group having 2 to 4 carbon atoms) oxy group as a constituent monomer. Aldehyde scavenger (X). The aldehyde scavenger according to claim 1, wherein the unsaturated monomer (b) has a poly (3 to 100) alkyleneoxy group. The aldehyde according to claim 1 or 2, wherein the weight ratio [(a) / (b)] of the (meth) acrylamide (a) to the unsaturated monomer (b) is 20/80 to 95/5. Capture agent. The aldehyde scavenger according to any one of claims 1 to 3, wherein the copolymer (A) has an acidic group and the acid value (unit: mgKOH / g) of the copolymer (A) is 2 to 160. .. The aldehyde scavenger according to any one of claims 1 to 4, wherein the copolymer (A) has a weight average molecular weight of 5,000 to 1,000,000. A polyacetal resin composition (Y) containing the aldehyde scavenger (X) according to any one of claims 1 to 5 and the polyacetal resin (D). The polyacetal resin composition according to claim 6, wherein the weight ratio [(A) / (D)] of the copolymer (A) to the polyacetal resin (D) is 0.05 / 99.95 to 5/95. thing. A molded product (Z) obtained by molding the polyacetal resin composition (Y) according to claim 6 or 7.