JP2009108305A - Polyvinyl acetal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyvinyl acetal which is excellent in crosslinking property, can form a cured product with excellent solvent resistance by crosslinking, and is excellent in solvent solubility and washing property. <P>SOLUTION: Provided is a polyvinyl acetal which comprises an acetal unit not containing a functional group, an acetal unit containing a crosslinking functional group R<SP>4</SP>represented by general formula (2), a vinyl alcohol unit and a vinyl ester unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to polyvinyl acetal. More specifically, the present invention relates to a polyvinyl acetal having a crosslinkable functional group.

  Water-insoluble polyvinyl acetal typified by polyvinyl butyral is easy to purify by washing with water after production, is flexible, has adhesion to various organic and inorganic substrates, is compatible with various compounds, is organic Excellent solubility in solvents and high weather resistance, widely used as various adhesives, binders for ceramics, various inks, paints, etc., and safety glass interlayers for buildings and automobiles Has been.

  In recent years, research on high functionality by introducing various functional groups into polyvinyl acetal has been conducted. As a method for introducing various functional groups into polyvinyl acetal, a method in which various compounds are reacted with a hydroxyl group possessed by polyvinyl acetal or a hydroxyl group possessed by polyvinyl alcohol which is a raw material of polyvinyl acetal is a common method. One.

As one of highly functionalized polyvinyl acetals, a polyvinyl acetal imparted with a crosslinking property, particularly a polyvinyl acetal into which an α, β-unsaturated carbonyl group is introduced is known.
For example, Patent Document 1 discloses a method for obtaining a polyvinyl acetal having an α, β-unsaturated carbonyl group introduced by dehydrating and esterifying polyvinyl alcohol and an unsaturated carboxylic acid in water, followed by acetalization. Yes. However, when polyvinyl acetal is obtained by such a method, the dehydration esterification reaction between polyvinyl alcohol and an unsaturated carboxylic acid does not proceed efficiently, so there is a problem in terms of productivity.
On the other hand, polyvinyl acetal obtained by dissolving polyvinyl acetal in an organic solvent and reacting with an unsaturated acid anhydride is reacted with polyvinyl acetal (Patent Document 2) or glycidyl methacrylate introduced with an α, β-unsaturated carbonyl group. There is also known a polyvinyl acetal (Patent Document 3) into which an α, β-unsaturated carbonyl group is obtained. However, these polyvinyl acetals are unfavorable from the environmental viewpoint because the crosslinkable functional group introduction reaction must be carried out in an organic solvent, and since polyvinyl acetal is obtained as a solution in an organic solvent used in the reaction, In order to remove the catalyst, unreacted compound, and by-product compound used in the process, a more complicated process such as reprecipitation is required.

  Furthermore, a polyvinyl acetal in which a carbon-carbon double bond is introduced by an acetalization reaction is also known (Patent Document 4), but the carbon-carbon double bond introduced into the polyvinyl acetal described in Patent Document 4 is an α, β-unsaturated. This polyvinyl acetal does not have sufficient crosslinking performance, as is clear from Comparative Example 2 described later, not a saturated carbonyl group.

  By the way, although polyvinyl acetal can be used as a powder coating material (patent document 5), generally polyvinyl acetal has a property which is easy to melt | dissolve in polar organic solvents, especially lower alcohols, such as ethanol and propanol. These organic solvents are used in household disinfectants, disinfectants and cleaning liquids, or wet tissues. Therefore, if these are used to wipe the coating film obtained from polyvinyl acetal, or the coating film is immersed in a cleaning solution, the coating film surface will be whitened and the appearance will be damaged, or the coating film will dissolve and the substrate will be exposed. The problem of becoming.

  In addition, when a circuit is printed on the surface of a green sheet using conventional polyvinyl butyral, there is a problem that a part of polyvinyl butyral is dissolved in an organic solvent in the conductor paste, and polyvinyl butyral is used. The green sheet is desired to have high solvent resistance. In recent years, there has been an increasing demand for smaller and thinner multilayer ceramic capacitors, and in order to increase the strength of green sheets that have been reduced in size and thickness, studies have been made on using polyvinyl butyral with a high degree of polymerization. Yes. However, since the molecular weight of the polyvinyl butyral used is large, the solution viscosity of the ceramic slurry becomes too high and the workability is lowered. Therefore, if the application to the multilayer ceramic capacitor is also taken into consideration, it is required to obtain high green sheet strength without increasing the molecular weight of polyvinyl butyral.

Japanese Patent Publication No. 60-8043 JP 09-249712 A JP 2004-339370 A JP 62-141033 A JP 2007-177211 A

  The present invention aims to solve the above-mentioned problems, and since it is water-insoluble, it can be easily purified by washing with water after production, and has the inherent flexibility, adhesiveness, and weather resistance of polyvinyl acetal. It is another object of the present invention to provide a polyvinyl acetal that is excellent in detergency and solubility in an organic solvent, and further excellent in solvent resistance after crosslinking.

  As a result of intensive studies, the present inventors have calculated one based on the amount of ethylene part in the main chain, each containing one or more structural units represented by the general formulas (1) to (4) (1). The total amount of the structural unit represented by (a) is a mol%, the total amount of the structural unit represented by (2) is b mol%, the total amount of the structural unit represented by (3) is c mol%, and (4) When the total amount of the structural units shown is d mol%, the structural ratio between a, b, c and d is 40 to 85 mol% for a, 0.1 to 40 mol% for b, and 10 to 10 for c. A polyvinyl acetal having 50 mol% and d of 0.1 to 30 mol% was found, and the present invention was completed.

Ｒ^１は水素原子または炭素数１〜１０の炭化水素基を表す。Ｒ^２、Ｒ^３は水素原子またはメチル基を表す。

R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ² and R ³ represent a hydrogen atom or a methyl group.

Ｒ^４は一般式（５）または（６）で表される官能基を含む基を表す。Ｒ^５、Ｒ^６は水素原子またはメチル基を表す。

R ⁴ represents a group containing a functional group represented by the general formula (5) or (6). R ⁵ and R ⁶ represent a hydrogen atom or a methyl group.

Ｒ^７は水素原子またはメチル基を表す。

R ⁷ represents a hydrogen atom or a methyl group.

Ｒ^８は水素原子またはメチル基を表す。Ｒ^９は水素原子または炭素数１〜９の炭化水素基を表す。

R ⁸ represents a hydrogen atom or a methyl group. R ⁹ represents a hydrogen atom or a hydrocarbon group having 1 to 9 carbon atoms.

Ｘ^１はＯ、ＳおよびＮＲ^１２からなる群から選ばれる基を表す。
Ｒ^１０は水素原子、メチル基、ＣＨ_２ＣＯＯＲ^１３およびＣＨ_２ＣＯＯＭ^１からなる群から選ばれる基を表す。
Ｒ^１１は水素原子、ＣＯＯＲ^１４およびＣＯＯＭ^２からなる群から選ばれる基を表す。
Ｒ^１２、Ｒ^１３およびＲ^１４は、水素原子または炭素数１〜１０の炭化水素基を表し、同一であっても異なってもよい。
Ｍ^１およびＭ^２は、アルカリ金属、アルカリ土類金属またはアンモニウム基のいずれかを表し、同一であっても異なってもよい。

X ¹ represents a group selected from the group consisting of O, S and NR ¹² .
R ¹⁰ represents a group selected from the group consisting of a hydrogen atom, a methyl group, CH ₂ COOR ¹³ and CH ₂ COOM ¹ .
R ¹¹ represents a group selected from the group consisting of a hydrogen atom, COOR ¹⁴ and COOM ² .
R ¹² , R ¹³ and R ¹⁴ represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different.
M ¹ and M ^{2 each} represents an alkali metal, an alkaline earth metal, or an ammonium group, and may be the same or different.

Ｘ^２はＯ、ＳおよびＮＲ^１６からなる群から選ばれる基を表す。
Ｒ^１５はＣＯＯＲ^１７ またはＣＯＯＭ^３を表す。
Ｒ^１６およびＲ^１７は、水素原子または炭素数１〜１０の炭化水素基を表し、同一であっても異なってもよい。
Ｍ^３はアルカリ金属、アルカリ土類金属またはアンモニウム基のいずれかを表す。

X ² represents a group selected from the group consisting of O, S and NR ¹⁶ .
R ¹⁵ represents COOR ¹⁷ or COOM ³ .
R ¹⁶ and R ¹⁷ represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different.
M ³ represents an alkali metal, alkaline earth metal or ammonium group.

In the present invention, in general formula (5), it is more preferable that X ¹ is NR ¹² , R ¹⁰ is a hydrogen atom or a methyl group, and R ¹¹ is a hydrogen atom.

  Moreover, it is also suitable for the polyvinyl acetal of this invention that an average particle diameter is 30-1000 micrometers and a bulk density is 0.12-0.5 g / mL.

Since the polyvinyl acetal of the present invention is water-insoluble, it can be easily purified by washing with water after production, has the flexibility, adhesiveness and weather resistance inherent to polyvinyl acetal, has good cleanability, and is organic. It has excellent solubility in solvents and excellent solvent resistance after crosslinking.
Here, “good detergency” means that impurities contained in polyvinyl acetal can be easily removed by washing the resin obtained after the reaction with water or washing with an appropriate organic solvent and drying.
Further, “excellent solubility in organic solvent” means that a solvent in which polyvinyl acetal dissolves polyvinyl acetal, such as ethanol, propanol, butanol, methyl ethyl ketone, 1,4-dioxane, tetrahydrofuran, ethyl acetate, chloroform, N, N— It means dissolving in dimethylformamide, dimethyl sulfoxide, etc. in a short time.
Furthermore, "excellent solvent resistance after crosslinking" means that a crosslinked structure is formed between the polyvinyl acetal molecules by heat treatment or irradiation with light such as electron beams or ultraviolet rays on the coating film or film obtained from polyvinyl acetal. It has excellent solvent resistance to solvents that dissolve polyvinyl acetal, such as ethanol, propanol, butanol, methyl ethyl ketone, 1,4-dioxane, tetrahydrofuran, ethyl acetate, chloroform, N, N-dimethylformamide, dimethyl sulfoxide, and the like. means.

  In addition, coating is performed using the powder coating material containing the polyvinyl acetal of the present invention, followed by heat treatment or light irradiation, thereby forming a crosslinked structure between the polyvinyl acetal molecules and imparting solvent resistance to the coating film. It has the feature of being.

The polyvinyl acetal of the present invention contains at least one type of structural units represented by the general formulas (1) to (4), and the structure represented by (1) calculated based on the amount of ethylene part in the main chain. The total amount of the unit is a mol%, the total amount of the structural unit represented by (2) is b mol%, the total amount of the structural unit represented by (3) is c mol%, and the structural unit represented by (4) When the total amount is d mol%, it is important that each structural unit is in the following range between a, b, c, and d.
a is 40-85 mol%, More preferably, it is 50-85 mol%, More preferably, it is 55-85 mol%. b is 0.1-40 mol%, More preferably, it is 1-35 mol%, More preferably, it is 2-30 mol%. c is 10 to 50 mol%, more preferably 10 to 45 mol%, still more preferably 10 to 40 mol%. d is 0.1-30 mol%, More preferably, it is 0.1-25 mol%, More preferably, it is 0.1-15 mol%.
When a, b, c, and d are in the above ranges, they are water-insoluble and thus easy to purify by washing with water after production, while having the flexibility, adhesiveness, and weather resistance inherent in polyvinyl acetal, and A polyvinyl acetal having good detergency, excellent solubility in an organic solvent, and excellent solvent resistance after crosslinking can be obtained. In the present invention, unless otherwise specified, “acetal” representing the ring structures of (1) and (2) refers to both a 6-membered ring and a 5-membered ring. However, since a 6-membered ring usually occupies most, only a 6-membered ring is shown in the formula.
The ethylene part in the main chain refers to a (—CH ₂ —CH—) moiety.

  The content of the structural units represented by the general formulas (1) to (4) of the polyvinyl acetal of the present invention is calculated by calculating each value of a + b, c, d by the method described in Example 1 described later (analysis according to JIS K6728). The value of b is calculated by analysis by 1H-NMR).

In the present invention, R ² , R ³ and R ^{5 to} R ⁸ in the general formulas (1) to (4) each represent a hydrogen atom or a methyl group, and all of them are particularly preferably hydrogen atoms.

In the present invention, R ¹ of the structural unit represented by the general formula (1) is not particularly limited as long as it is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. However, R ¹ does not include a hetero atom. Examples of the hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, 2- Alkyl groups such as pentyl group, n-heptyl group, 3-heptyl group, n-octyl group, n-nonyl group, n-decyl group, phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group In addition to aryl groups such as 4-ethylphenyl group and 4-n-butylphenyl group, there may be mentioned 3-cyclohexenyl group, 4-cyclohexenyl group, benzyl group, etc. Among them, n-propyl group is particularly preferable. It is.

In the present invention, R ⁴ of the structural unit represented by the general formula (2) is a group containing a functional group represented by the general formula (5) or (6).

In the general formula (5), X ¹ is not particularly limited as long as X ¹ is a group selected from the group consisting of O, S and NR ^12, but among these, O or NR ¹² is particularly preferable. R ¹² is not particularly limited as long as it is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Examples of the hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, 2- Alkyl groups such as pentyl group, n-heptyl group, 3-heptyl group, n-octyl group, n-nonyl group, n-decyl group, phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group In addition to aryl groups such as 4-ethylphenyl group and 4-n-butylphenyl group, benzyl group and the like can be mentioned, and among these, a hydrogen atom or a methyl group is particularly preferable.

R ¹⁰ is not particularly limited as long as R ¹⁰ is a group selected from the group consisting of a hydrogen atom, a methyl group, CH ₂ COOR ¹³ and CH ₂ COOM ¹ , and R ¹¹ is selected from the group consisting of a hydrogen atom, COOR ¹⁴ and COOM ² The group is not particularly limited as long as it is a group. Here, R ¹³ and R ¹⁴ are not particularly limited as long as they are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Examples of the hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and an n-propyl group. , Isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, 2-pentyl group, n-heptyl group, 3-heptyl group, n-octyl group, n-nonyl Group, alkyl group such as n-decyl group, and aryl group such as phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group, 4-ethylphenyl group, 4-n-butylphenyl group, A benzyl group etc. are mentioned, Among these, a hydrogen atom or a C1-C4 alkyl group is especially suitable. M ¹ and M ² are each an alkali metal such as lithium, sodium, potassium, rubidium, or cesium; an alkaline earth metal such as magnesium, calcium, strontium, or barium; or an ammonium group such as a triethylammonium group or a pyridinium group. Any one is not particularly limited. Of these, alkali metals or alkaline earth metals are particularly preferred.

Of these groups containing the functional group represented by the general formula (5), it is most preferable that X ¹ is NR ¹² , R ¹⁰ is a hydrogen atom or a methyl group, and R ¹¹ is a hydrogen atom.

In the general formula (6), X ² is not particularly limited as long as it is a group selected from the group consisting of O, S and NR ^16, but among these, O or NR ¹⁶ is particularly preferable. R ¹⁶ is not particularly limited as long as it is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Examples of the hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, 2- Alkyl groups such as pentyl group, n-heptyl group, 3-heptyl group, n-octyl group, n-nonyl group, n-decyl group, phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group In addition to aryl groups such as 4-ethylphenyl group and 4-n-butylphenyl group, benzyl group and the like are preferable, and among these, a hydrogen atom or a methyl group is particularly preferable.

R ¹⁵ is not particularly limited as long as it is CH ₂ COOR ¹⁷ or CH ₂ COOM ³ . R ¹⁷ is not particularly limited as long as it is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Examples of the hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, 2- Alkyl groups such as pentyl group, n-heptyl group, 3-heptyl group, n-octyl group, n-nonyl group, n-decyl group, phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group In addition to aryl groups such as 4-ethylphenyl group and 4-n-butylphenyl group, benzyl group and the like are preferable. Among these, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is particularly preferable.

M ³ is any one of an alkali metal such as lithium, sodium, potassium, rubidium and cesium, an alkaline earth metal such as magnesium, calcium, strontium and barium, or an ammonium group such as triethylammonium group and pyridinium group. If it does not specifically limit. Of these, alkali metals or alkaline earth metals are particularly preferred.

The group represented by the general formula (5) or (6) has a highly reactive α, β-unsaturated carbonyl group in any case regardless of the types of R ¹⁰ , R ¹¹ and R ^15. ing. Since the polyvinyl acetal of the present invention contains an α, β-unsaturated carbonyl group as an essential constituent unit, it has high crosslinking performance.

In the present invention, R ⁹ of the structural unit represented by the general formula (4) is not particularly limited as long as it is a hydrogen atom or a hydrocarbon group having 1 to 9 carbon atoms. Examples of the hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, 2- Alkyl groups such as pentyl group, n-heptyl group, 3-heptyl group, n-octyl group, n-nonyl group, phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group, 4-ethylphenyl In addition to aryl groups such as groups, benzyl groups and the like can be mentioned, and among these, methyl groups are particularly preferred.

The polyvinyl acetal of the present invention may contain structural units other than the structural units represented by the general formulas (1) to (4) as long as the object of the present invention is not impaired. In that case, the kind of structural units other than the structural units represented by the general formulas (1) to (4) is not particularly limited, and a monomer unit other than the vinyl ester monomer derived from polyvinyl alcohol described later, or Examples include acetal units other than the structural units represented by the general formulas (1) and (2) contained in the polyvinyl acetal.
At this time, the amount of the structural unit other than the structural units represented by the general formulas (1) to (4) is the total amount of the structural units represented by the general formulas (1) to (4) defined in the present invention. It is not taken into account when calculating. The amount of the structural unit other than the structural units represented by the general formulas (1) to (4) is not particularly limited, but in the general formulas (1) to (4) calculated based on the amount of ethylene part in the main chain. When the total of the structural units represented is 100 mol%, the amount of the structural units other than the general formulas (1) to (4) is preferably less than 10 mol% with respect to the ethylene part in the main chain.

Next, a method for producing the polyvinyl acetal of the present invention will be described.
Although the method for synthesizing the polyvinyl acetal of the present invention is not particularly limited, when the polyvinyl alcohol is acetalized according to the acetalization reaction of polyvinyl alcohol described later, formaldehyde or a hydrocarbon group having 1 to 10 carbon atoms is a formyl group as an aldehyde. The most common method is coacetalization using both an aldehyde directly bonded to aldehyde, or a dialkyl acetal of the aldehyde and an aldehyde having a functional group represented by the general formula (5) or (6), or a dialkyl acetal thereof. Convenient.

Aldehydes in which a hydrocarbon group having 1 to 10 carbon atoms is directly bonded to a formyl group, or dialkyl acetals of these aldehydes are not particularly limited, but acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-pentylaldehyde, 3- Methylbutyraldehyde, 2-methylbutyraldehyde, 2,2-dimethylpropionaldehyde, n-hexylaldehyde, 2-methylpentylaldehyde, n-octylaldehyde, 2-ethylhexylaldehyde, n-nonylaldehyde, n-decylaldehyde, n -Aliphatic aldehydes such as undecyl aldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, 4-ethylbenzaldehyde, Other aromatic aldehydes such -n- butyl benzaldehyde, phenylacetaldehyde, and n- butyraldehyde dimethyl acetal, although such n- butyraldehyde diethyl acetal, these out n- butyl aldehyde is particularly preferred.
Only one kind of aldehyde in which a hydrocarbon group having 1 to 10 carbon atoms is directly bonded to a formyl group or a dialkyl acetal of these aldehydes may be used, or two or more kinds may be used as necessary.

  The aldehyde having the functional group represented by the general formula (5) or (6), or a dialkyl acetal thereof is not particularly limited, but the functional group represented by the general formula (5) or (6), a formyl group or a dialkyl acetal The groups are linked via a group comprising one or more functional groups or bonds selected from an alkylene group, an arylene group, a carbonyl group, an amide group, an amino group, an ether bond, an ester bond, a urea bond, and a urethane bond. It is more preferable that they are linked via a group consisting of one or more functional groups or bonds selected from an alkylene group, an arylene group, a carbonyl group, an ether bond, an ester bond, a urea bond, and a urethane bond, Most preferably, they are linked by an alkylene group. Further, the group connecting the functional group represented by the general formula (5) or (6) and the formyl group or dialkyl acetal group may contain a functional group such as an alkyl group, an aryl group, a hydroxyl group, and a carboxyl group.

  The molecular weight of the aldehyde having the functional group represented by the general formula (5) or (6) or the dialkyl acetal thereof is not particularly limited, but is preferably 1000 or less, more preferably 500 or less.

Examples of the aldehyde having a functional group represented by the general formula (5) or (6) or a dialkyl acetal thereof include N- (2,2-dimethoxyethyl) (meth) acrylamide and N- (formylmethyl) (meth). Acrylamide, N- (2,2-diethoxyethyl) (meth) acrylamide, N- (2,2-diisopropoxyethyl) (meth) acrylamide, N- (2,2-dibutoxyethyl) (meth) acrylamide N- (2,2-di-t-butoxyethyl) (meth) acrylamide, N- (2-formylethyl) (meth) acrylamide, N- (3,3-dimethoxypropyl) (meth) acrylamide, N- (3,3-diethoxypropyl) (meth) acrylamide, N- (3,3-diisopropoxypropyl) (meth) acryl Amide, N- (3,3-dibutoxypropyl) (meth) acrylamide, N- (3,3-di-t-butoxypropyl) (meth) acrylamide, N- (3-formylpropyl) (meth) acrylamide, N- (4,4-dimethoxybutyl) (meth) acrylamide, N-4,4- (diethoxybutyl) (meth) acrylamide, N- (4,4-diisopropoxybutyl) (meth) acrylamide, N- (4,4-dibutoxybutyl) (meth) acrylamide, N- (4,4-di-t-butoxybutyl) (meth) acrylamide, N-methyl-N- (2,2-dimethoxyethyl) (meth) Acrylamide, N-methyl-N- (formylmethyl) (meth) acrylamide, N-methyl-N- (2,2-diethoxyethyl) (meth) acrylami N-methyl-N- (2,2-diisopropoxyethyl) (meth) acrylamide, N-methyl-N- (2,2-dibutoxyethyl) (meth) acrylamide, N-methyl-N- (2 , 2-di-t-butoxyethyl) (meth) acrylamide, and the like, and 4- (formylmethyl) amino-4-oxo-2-cis-butenoic acid, 4- (formyl) Methyl) amino-4-oxo-2-trans-butenoic acid, 4- (2,2-dimethoxyethyl) amino-4-oxo-2-cis-butenoic acid, 4- (2,2-dimethoxyethyl) amino- Sodium 4-oxo-2-cis-butenoate, potassium 4- (2,2-dimethoxyethyl) amino-4-oxo-2-cis-butenoate, bis {4- (2,2-dimethoxyethyl) amino No-4-oxo-2-cis-butenoic acid} calcium, 4- (2,2-dimethoxyethyl) amino-4-oxo-2-cis-butenoic acid ammonium, 4- (2,2-dimethoxyethyl) amino 4-Oxo-2-cis-butenoic acid methyl 4- (2,2-dimethoxyethyl) amino-4-oxo-2-trans-butenoic acid, 4- (2,2-diethoxyethyl) amino-4- Oxo-2-cis-butenoic acid, 4- (2,2-diethoxyethyl) amino-4-oxo-2-trans-butenoic acid, 4- (formylmethyl) amino-4-oxo-3-methylene-butane Acid, 4- (2,2-dimethoxyethyl) amino-4-oxo-3-methylene-butanoic acid, 4- (2,2-dimethoxybutyl) amino-4-oxo-3-methylene-butanoic acid, 4- (2,2-di Toxiethyl) amino-4-oxo-3-methylene-butanoic acid sodium, 4- (2,2-dimethoxyethyl) amino-4-oxo-3-methylene-butanoic acid potassium, bis {4- (2,2-dimethoxy Ethyl) amino-4-oxo-3-methylene-butanoic acid} calcium, methyl 4- (2,2-dimethoxyethyl) amino-4-oxo-3-methylene-butanoate, 4- (2,2-dimethoxyethyl) ) Amino-4-oxo-3-methylene-butanoic acid ammonium, 4- (formylmethyl) amino-4-oxo-2-methylene-butanoic acid, 4- (2,2-dimethoxyethyl) amino-4-oxo- 2-methylene-butanoic acid, 4- (2,2-dimethoxybutyl) amino-4-oxo-2-methylene-butanoic acid, 4- (2,2-dimethoxyethyl) Amino-4-oxo-2-methylene-butanoic acid sodium salt, 4- (2,2-dimethoxyethyl) amino-4-oxo-2-methylene-butanoic acid potassium salt, bis {4- (2,2-dimethoxyethyl) Amino-4-oxo-2-methylene-butanoic acid} calcium, 4- (2,2-dimethoxyethyl) amino-4-oxo-2-methylene-butanoic acid ammonium, 4- (2,2-dimethoxyethyl) amino Methyl 4-oxo-2-methylene-butanoate, N- (4-formylphenoxycarbonyl) -N- {2- (meth) acryloxyethyl} amine, N- (4-formylphenylthiocarbonyl) -N- {2- (meth) acryloxyethyl} amine, 2- (formylmethyl) amino-3- (meth) acryloxy-1-propanol, 1- (formyl Til) amino-3- (meth) acryloxy-2-propanol, 1-formylmethyl-3- {2- (meth) acryloxyethyl} urea, 1- (2,2-dimethoxyethyl) -3- {2- (Meth) acryloxyethyl} urea, 1- (4,4-dimethoxybutyl) -3- {2- (meth) acryloxyethyl} urea, 3-hydroxy-2- (meth) acryloxypropylglyoxylate, 2-hydroxy-3- (meth) acryloxypropyl glyoxylate, 3-hydroxy-2- (meth) acryloxypropyl terephthalaldehyde, 2-hydroxy-3- (meth) acryloxypropyl terephthalaldehyde, 4- (Meth) acryloxybenzaldehyde, 4- (4-formylphenoxy) -4-oxo-2-cis-butenoic acid, -(4-formylphenoxy) -4-oxo-2-trans-butenoic acid, 4- (4-formylphenoxy) -4-oxo-3-methylene-butanoic acid, 4- (4-formylphenoxy) -4- Oxo-2-methylene-butanoic acid, 2- (4-formylphenoxy) -3- (meth) acryloxy-1-propanol, 1- (4-formylphenoxy) -3- (meth) acryloxy-2-propanol, 2 -(4-formylphenoxycarbonylamino) ethyl (meth) acrylate, (meth) acryloxyacetaldehyde, 4- (formylmethoxy) -4-oxo-2-cis-butenoic acid, 4- (formylmethoxy) -4-oxo 2-trans-butenoic acid, 4- (formylmethoxy) -4-oxo-3-methylene-butanoic acid, 4- (formylmethate) Xy) -4-oxo-2-methylene-butanoic acid, 2- (formylmethoxy) ethyl (meth) acrylate, 4-dimethoxymethylphenylthio-4-oxo-2-cis-butenoic acid, 4-dimethoxymethylphenylthio -4-oxo-2-methylene-butanoic acid, (2,2-dimethoxyethoxy) ethyl (meth) acrylate, 4-dimethoxymethylbenzoic acid 2- (3-hydroxy-1-methacryloxy) propyl ester, 4-dimethoxymethyl Examples include 1- (3-hydroxy-1-methacryloxy) propyl ester of benzoic acid, but are not limited thereto.
As the aldehyde having a functional group represented by the general formula (5) or (6) or a dialkyl acetal thereof, only one kind may be used, or two or more kinds may be used if necessary.

  In an acetalization reaction of polyvinyl alcohol described later, an aldehyde in which a hydrocarbon group having 1 to 10 carbon atoms is directly bonded to a formyl group, or a dialkyl acetal of these aldehydes, and a functional group represented by (5) or (6) The method of adding aldehydes or their dialkyl acetals is not particularly limited. For example, all aldehydes to be used and dialkyl acetals of aldehydes may be mixed and added, or may be added separately.

  The method for obtaining the aldehyde having the functional group represented by the general formula (5) or (6) or the dialkyl acetal thereof is not particularly limited. For example, the reaction of the compound arbitrarily selected from “Raw compound 1” shown below with the compound arbitrarily selected from “Raw compound 3”, or the compound arbitrarily selected from “Raw compound 2” and “Raw compound” It can be obtained by reaction with a compound arbitrarily selected from “4”, among which (meth) acrylic acid chloride of “raw compound 1” and α-aminoacetaldehyde and α-aminoacetaldehyde dimethyl acetal of “raw compound 3” Particularly preferred are those obtained by reaction with a compound selected from γ-aminobutyraldehyde and γ-aminobutyraldehyde dimethyl acetal.

Examples of the compound belonging to “Raw compound 1” include (meth) acrylic acid chloride, maleic anhydride, itaconic anhydride, glycidyl methacrylate, and 2-isocyanatoethyl (meth) acrylate.
Examples of the compound belonging to “Raw compound 2” include 2-hydroxyethyl (meth) acrylate and decaethylene glycol monoacrylate.
The compounds belonging to “Raw Material Compound 3” are α-aminoacetaldehyde, α-aminoacetaldehyde dimethyl acetal, γ-aminobutyraldehyde, γ-aminobutyraldehyde dimethyl acetal, glyoxylic acid, glyoxylic acid dimethyl acetal, terephthalaldehyde acid, terephthalaldehyde Examples include acid dimethyl acetal, 4-hydroxybenzaldehyde, 4-hydroxybenzaldehyde dimethyl acetal, and 4-mercaptobenzaldehyde.
Examples of the compound belonging to “Raw compound 4” include α-chloroacetaldehyde and α-chloroacetaldehyde dimethyl acetal.

  Reaction between a compound arbitrarily selected from “Raw Compound 1” and a compound arbitrarily selected from “Raw Compound 3”, or a compound arbitrarily selected from “Raw Compound 2”, and arbitrarily selected from “Raw Compound 4” Conditions for carrying out the reaction with the selected compound can be appropriately selected according to the type of the raw material compound used, but the raw material compound is mixed in an appropriate solvent or under neat conditions, and the reaction temperature is −30 to 200 ° C., preferably Is carried out at a temperature of −10 to 100 ° C. for 10 minutes to 50 hours, preferably 1 to 10 hours. Here, the neat condition represents a condition in which no solvent is used. In addition, if necessary, an organic acid such as acetic acid and p-toluenesulfonic acid, an inorganic acid such as hydrochloric acid, sulfuric acid and nitric acid, an organic base such as pyridine and triethylamine, and an inorganic base such as sodium hydroxide and sodium hydrogen carbonate are used as a reaction catalyst. May be added as hydroquinone, 4-methoxyphenol, 3,5-di-tert-butyl-4-hydroxytoluene, 2,2-methylene-bis (4-methyl-6-tert-butylphenol), 1, 1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, dilauryl thiodipropionate, triphenyl phosphite, phenothiazine, 2,2,6,6-tetramethyl-1- Piperidinyloxy or the like may be added as a polymerization inhibitor.

  Polyvinyl alcohol used as a raw material for polyvinyl acetal can be obtained by a conventionally known method, that is, by polymerizing a vinyl ester monomer and saponifying the obtained polymer. As a method for polymerizing the vinyl ester monomer, conventionally known methods such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method can be employed. As the catalyst used for the polymerization, an azo catalyst, a peroxide catalyst, a redox catalyst or the like is appropriately selected according to the polymerization method employed. The saponification reaction can be carried out by alcoholysis or hydrolysis using a conventionally known alkali catalyst or acid catalyst. Among them, methanol is used as a solvent, and saponification reaction using caustic soda (sodium hydroxide) as a catalyst is simple. Yes, most preferred.

  Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, and palmitic acid. Examples thereof include vinyl, vinyl stearate, vinyl oleate, vinyl benzoate, and isopropenyl acetate, and vinyl acetate is particularly preferable.

  In addition, the vinyl ester monomer can be used by being copolymerized with other monomer units as long as the gist of the present invention is not impaired. Examples of the monomer units include, for example, α-olefins such as ethylene, propylene, N-butene, and isobutylene; acrylic acid and salts thereof; methyl acrylate, ethyl acrylate, N-propyl acrylate, i-propyl acrylate Acrylic acid esters such as N-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid and salts thereof; methyl methacrylate, methacrylic acid Methacrylic acid such as ethyl acetate, N-propyl methacrylate, i-propyl methacrylate, N-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate Beauty treatment Acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide, acrylamide propane sulfonic acid and its salt, acrylamidopropyldimethylamine and its salt, quaternary salt thereof, N-methylol acrylamide And acrylamide derivatives thereof; methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and salts thereof, methacrylamidepropyldimethylamine and salts thereof, quaternary salts thereof, N-methylolmethacrylate Methacrylamide derivatives such as amides and derivatives thereof; methyl vinyl ether, ethyl vinyl ether, N-propyl vinyl ether, i-propyl vinyl ether Vinyl ethers such as tellurium, N-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; Examples thereof include vinylidene halides such as vinylidene and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid and salts thereof, esters or anhydrides thereof, and vinylsilyl compounds such as vinyltrimethoxysilane. These monomer units are polymerized using less than 100 mol% of the vinyl ester monomer used in the reaction, and less than 10 mol% with respect to the main chain ethylene part of the resulting polyvinyl alcohol. It is preferable that it is content of.

  The preferable polymerization degree of the vinyl ester monomer in polyvinyl alcohol is 100 to 3000, and more preferably 200 to 2000.

Next, the acetalization reaction of polyvinyl alcohol will be described.
First, an aqueous solution of a vinyl alcohol polymer having a concentration of 3 to 15% by weight is adjusted to a temperature range of 80 to 100 ° C., and the temperature is gradually cooled over 10 to 60 minutes. When the temperature is lowered to −10 to 30 ° C., an aldehyde and an acid catalyst are added, and an acetalization reaction is performed for 30 to 300 minutes while keeping the temperature constant. Thereafter, the reaction solution is heated to a temperature of 40 to 80 ° C. over 30 to 200 minutes, and the temperature is maintained for 60 to 360 minutes. Next, the reaction solution is preferably cooled to room temperature, washed with water, neutralized as necessary, and dried.

  It does not specifically limit as an acid catalyst used for acetalization reaction, Any organic acid and inorganic acid can be used, For example, an acetic acid, paratoluenesulfonic acid, nitric acid, a sulfuric acid, hydrochloric acid etc. are mentioned. Among these, hydrochloric acid, sulfuric acid, and nitric acid are more generally used, and hydrochloric acid is particularly preferably used.

When the polyvinyl acetal of the present invention obtained by the above method contains a carboxyl group and a carboxylate group, the ratio of the carboxyl group to the carboxylate group may be appropriately selected according to the purpose. And the carboxylate group is contained in a total of 0.1 mol% or more, and adjusting the content ratio thereof to the range of the following formula (7) suppresses the hygroscopicity of the polyvinyl acetal, for example, using the polyvinyl acetal of the present invention. From the viewpoint of preventing white turbidity due to moisture absorption or deformation due to moisture absorption.
0 ≦ [Amount of carboxylate group / (total amount of carboxyl group and carboxylate group)] ≦ 0.3 (7)
In the present invention, the carboxylate group means a group in which a proton of a carboxyl group (—COOH) is replaced with a monovalent or polyvalent alkali (earth) metal ion or various ammonium ions. In the present invention, the carboxylate group is typically neutralized with an alkali metal salt such as sodium hydroxide, an alkaline earth metal salt such as magnesium hydroxide, and an amine such as ammonia or pyridine. To be generated.
As described later, the measurement method of the above formula (7) can be obtained by dissolving polyvinyl acetal in ethanol and titrating with an aqueous sodium hydroxide solution and hydrochloric acid using an indicator.
The carboxyl group and carboxylate group herein include those introduced into either the main chain or the side chain of polyvinyl acetal. The total introduction amount of carboxyl groups and carboxylate groups is a value calculated based on the main chain ethylene part of polyvinyl acetal, and the above content ratio is a value calculated based on the molar ratio of carboxyl groups and carboxylate groups. It is.

  The polyvinyl acetal of the present invention has an average particle size of 30 to 1000 μm, preferably 30 to 500 μm, more preferably 30 to 300 μm, and a bulk density of 0.12 to 0.5 g / mL, preferably 0.12. It is preferable to be in the form of a porous powder of ~ 0.4 g / mL, more preferably 0.12 to 0.3 g / mL. When the polyvinyl acetal is obtained as a porous powder having the above average particle diameter and bulk density, water or an organic solvent is likely to penetrate into the particles of the polyvinyl acetal, and Mamako may be dissolved when trying to dissolve in the solvent. Since it is difficult to produce, it is excellent in cleanability and solvent solubility.

The average particle diameter of polyvinyl acetal can be determined by, for example, laser diffraction measurement. Examples of the apparatus that can be used for the measurement include a particle size distribution measuring apparatus SALD2200 manufactured by Shimadzu Corporation.
Moreover, the bulk density of polyvinyl acetal can be measured based on, for example, JIS K6721.

  The method for obtaining the polyvinyl acetal having the above average particle diameter and bulk density is not limited, but can be used as it is when the polyvinyl acetal obtained by the acetalization reaction of polyvinyl alcohol described above satisfies the above range. Further, the average particle diameter and bulk density can be adjusted to the above ranges by a method such as pulverization or sieving.

Using the polyvinyl acetal of the present invention, a coating film can be formed by melting with a crosslinking initiator or dissolving in a solvent, casting on a substrate, and drying, if necessary. The drying is preferably performed at a temperature of 10 to 150 ° C. for 10 minutes to 24 hours. A cured product can be obtained by subjecting the coating film thus obtained to a treatment such as UV irradiation, electron beam irradiation, or heat treatment.
Although it does not specifically limit as a kind of crosslinking initiator, Alkyl peroxide ester, such as cumyl hydroperoxide, t-butyl perbenzoate, i-propyl peracetate; dialkyl peroxides such as t-butyl peroxide; azo compounds such as α, α-azobisisobutyronitrile, azobiscyclohexanecarbonitrile, 2,2-azobis-2,4-dimethylvaleronitrile, benzophenone, 2 -Hydroxy-4 '-(2-hydroxyethoxy) -2-methylpropiophenone, α, α-dimethoxy-α-monoforino-methylthiophenylacetophenone, 2,4,6-trimethylbenzoylphosphine oxide, thioxanthone, tetramethylthiuram The Photoinitiators such as Rufaido the like.

  The cured product thus obtained is a solvent that dissolves polyvinyl acetal, such as ethanol, propanol, butanol, methyl ethyl ketone, 1,4-dioxane, tetrahydrofuran, ethyl acetate, chloroform, N, N-dimethylformamide, dimethyl sulfoxide, and the like. For example, the degree of the solvent resistance can be expressed by using, as an index, the residual ratio of a cured product (film, etc.) when immersed in ethanol kept at 50 ° C. for 2 hours. For example, the residual ratio is preferably 70 to 100%, and more preferably 80 to 100%.

The polyvinyl acetal of the present invention is useful as a powder coating material. This will be described below.
As the polyvinyl acetal used for the powder coating material, those having the above average particle diameter are preferably used. Further, the average particle diameter is preferably 150 μm or less, more preferably 130 μm or less, optimally 100 μm or less. When the polyvinyl acetal is obtained as a powder having such an average particle diameter, it can be used as a powder coating as it is, and if necessary, a pulverization method, a spray drying method, a VAMP method, sieving, etc. It is also possible to adjust to the average particle size by the above method. When the average particle diameter satisfies this range, a coating film after powder coating can be obtained with a more uniform thickness.

  The average particle diameter of the polyvinyl acetal powder used for the powder coating can be determined by, for example, measurement by a laser diffraction method.

  The above-mentioned crosslinking initiator is added to the powder coating material as necessary. The addition method of the crosslinking initiator is not particularly limited, but it may be contained in polyvinyl acetal, or polyvinyl acetal and the crosslinking initiator may be dry blended.

  For powder coatings, polyvinyl acetal is used as an essential component of the resin component, but other resins, in addition to dye pigments, antioxidants, plasticizers, flow modifiers, and other additives, As long as the object of the present invention is not hindered, it can be used as needed. Although there is no particular limitation on the addition method thereof, polyvinyl acetal may be contained, or polyvinyl acetal and an additive may be dry blended.

  From the viewpoint of the surface smoothness of the coating film to be formed, the polyvinyl acetal used for the powder coating preferably has a water content of 2.5% by weight or less, and more preferably 2.0% by weight or less. . As a method of making the water content of polyvinyl acetal 2.5% by weight or less, the polyvinyl acetal is washed with water or a mixed solution of water / alcohol, and then dried to remove the water to a specified amount or less. And the like.

  The powder paint can be applied to the substrate by various methods. Examples of the method include fluid dipping, electrostatic coating, and thermal spraying. Although the temperature conditions at the time of coating vary depending on the coating method employed and the type of polyvinyl acetal used, about 100 to 300 ° C. is preferable.

  Examples of the base material to be painted include ceramics, ceramics, glass, plastics, etc., in addition to metals such as steel pipes and steel plates. In general, when powder coating is applied to these metals, degreasing, phosphate treatment, plating, etc. are expected with the expectation that the adhesion between the metal and the coating film, the corrosion resistance of the metal, and the appearance will be improved. Application of an epoxy resin or the like for the purpose of pretreatment or primer treatment is performed as necessary. A multilayer structure can be obtained by coating the surface of the base material with the powder coating material mainly composed of the polyvinyl acetal of the present invention. At this time, multilayering with other resin layers can also be performed as necessary. The method for performing multilayering is not particularly limited, but a method of performing powder coating a plurality of times, a mixture of the powder coating of the present invention and another resin is melted, and phase separation is performed due to a difference in affinity to perform coating once. And a method of obtaining two or more resin layers. Among these, the method of performing powder coating a plurality of times is preferable because it is not necessary to consider the affinity between resins.

  Since the polyvinyl acetal of the present invention becomes a cured product having excellent solvent resistance by UV irradiation, electron beam irradiation, and heat treatment, it can be applied to various applications. For example, curable ceramic compositions, photosensitive compositions, curable ink compositions (for letterpress printing, gravure printing, offset printing, screen printing, ink jet printing), curable powder coatings, curable coatings, automotive or architectural Although it can be applied to a curable intermediate film of glass, a curable binder for inorganic materials, a curable adhesive, and the like, it can be suitably used particularly as a curable powder coating. The polyvinyl acetal of the present invention is used as a binder or an adhesive for these compositions. In each of these uses, components necessary for each use are appropriately blended and used. Further, if necessary, a diluent solvent, a pigment, a filler, an antioxidant, a plasticizer and the like can be blended and used.

  The polyvinyl acetal according to the present invention is particularly useful as a binder for a crosslinkable ceramic composition for green sheets. That is, the ceramic composition (slurry) prepared using the polyvinyl acetal of the present invention has the same degree of polymerization as that of the polyvinyl acetal of the present invention, and the structural unit represented by the general formula (2). It has a viscosity comparable to that of a composition (slurry) obtained using polyvinyl acetal not contained, and is excellent in workability. After producing a crosslinkable ceramic green sheet using this composition, a ceramic green sheet can be obtained by performing UV crosslinking, electron beam crosslinking, thermal crosslinking, or the like. Since this ceramic green sheet is strengthened by crosslinking, it is suitable as a small, thin ceramic green sheet, and at the same time, it can be given solvent resistance, so a circuit is printed on the surface of the green sheet. In this case, it is possible to realize printing that is extremely clear and free from defects such as pinholes caused by melting the green sheet.

  The ceramic composition of the present invention can be obtained by dispersing and dissolving the polyvinyl acetal and ceramic powder described in the present application in an appropriate solvent. Here, the polyvinyl acetal is preferably contained in an amount of 1 to 20% by weight, preferably 3 to 17% by weight, based on the ceramic composition.

  The solvent used in the ceramic composition of the present invention is not particularly limited as long as it is a solvent that dissolves polyvinyl acetal and a plasticizer, a dispersant, a crosslinking initiator, and other additives described later, but ethanol, propanol, butanol, Methanol, toluene, xylene, acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, ethyl acetate, and the like are preferably used, and two or more of these solvents can be mixed and used. The amount of these solvents used is preferably 10 to 80% by weight, more preferably 15 to 70% by weight in the ceramic composition.

  The type of the ceramic powder used in the ceramic composition of the present invention is not particularly limited. For example, barium titanate, alumina, zirconia, aluminum silicate, titanium oxide, zinc oxide, magnesia, sialon, spinel, mullite, glass, Examples thereof include powders such as silicon carbide, silicon nitride, and aluminum nitride, and these can be used in combination of two or more.

  Although the usage-amount of a ceramic powder is not specifically limited, It is preferable to use 20 to 80 weight% in a ceramic composition, and it is 30 to 75 weight% more suitably.

  The average particle size of the ceramic powder is appropriately selected according to the thickness of the ceramic green sheet to be produced, preferably 10 μm or less, and more preferably 1 μm or less.

  If necessary, a plasticizer can be added to the ceramic composition of the present invention. The type of plasticizer to be added is not particularly limited, but phthalic acid such as dioctyl phthalate, benzyl butyl phthalate, dibutyl phthalate, dihexyl phthalate, di (2-ethylhexyl) phthalate, and di (2-ethylbutyl) phthalate Plasticizers, adipic acid plasticizers such as dihexyl adipate, glycol plasticizers such as ethylene glycol, diethylene glycol, triethylene glycol, triethylene glycol dibutyrate, triethylene glycol di (2-ethylbutyrate), triethylene Examples include glycol ester plasticizers such as glycol di (2-ethylhexanoate), and these may be used in combination of two or more. Although the usage-amount of a plasticizer is not specifically limited, It is preferable to use 0.1 to 10 weight% in a ceramic composition, and it is 1 to 8 weight% more suitably.

  If necessary, a crosslinking initiator can be added to the ceramic composition of the present invention. The kind of the crosslinking initiator that can be added can be appropriately selected depending on the crosslinking method, and examples thereof include the aforementioned crosslinking initiators. Although the usage-amount of a crosslinking initiator is not specifically limited, It is preferable to use 0.001-1 weight% in a ceramic composition, More preferably, it is 0.01-0.5 weight%.

  The ceramic composition of the present invention may contain a dispersant, a lubricant, an antistatic agent, an antifoaming agent and the like as necessary. These addition amounts are preferably used in an amount of 0.1 to 3% by weight, more preferably 0.1 to 1% by weight, based on the ceramic composition.

  In the ceramic composition of the present invention, the polyvinyl acetal, ceramic powder, and other additives described in the present application are mixed with an appropriate solvent, mixed at 0 to 100 ° C. for 1 to 100 hours using a ball mill, and the like. After defoaming, a crosslinkable ceramic green sheet is provided by applying on a substrate having excellent peelability such as a polyester film and drying the organic solvent.

  The obtained crosslinkable ceramic green sheet gives a ceramic green sheet that has been lightly or thermally crosslinked by irradiation with light such as UV, electron beam irradiation, heat treatment or the like. These are suitable from the viewpoint of increasing the strength of the ceramic green sheet and imparting solvent resistance.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, “%” and “part” mean “% by weight” and “part by weight” unless otherwise specified.

Example 1
(Synthesis of dimethyl acetal of aldehyde having a crosslinkable functional group)
A 3 L separable flask was charged with 2 L of acetone and cooled to 0 ° C. 196 g of methacrylic acid chloride, 205 g of α-aminoacetaldehyde dimethyl acetal and 200 g of triethylamine were added thereto, and the reaction was carried out for 3 hours while maintaining at 0 ° C. After completion of the reaction, acetone was distilled off under reduced pressure, extracted with water / ethyl acetate, and the solvent was distilled off under reduced pressure to obtain 223 g of N- (2,2-dimethoxyethyl) methacrylamide.
(Synthesis of polyvinyl acetal)
A 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade was charged with 3375 g of ion-exchanged water and 275 g of polyvinyl alcohol (PVA-1: polymerization degree 300, saponification degree 98 mol%) (PVA concentration 7). 0.5%), the whole was heated to 95 ° C. and completely dissolved. Next, after gradually cooling to 7 ° C over about 30 minutes with stirring at 120 rpm, the solution was kept at 7 ° C and 157 g of n-butyraldehyde, 110 g of N- (2,2-dimethoxyethyl) methacrylamide and 20% Hydrochloric acid 200mL was added and acetalization reaction was performed for 150 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 120 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-1). The degree of acetalization of the obtained PVB-1 was 81 mol% {degree of acetalization with n-butyraldehyde (a) 66 mol%, degree of acetalization with N- (2,2-dimethoxyethyl) methacrylamide (b) 15 Mol%}, the vinyl alcohol group content (c) was 17 mol%, and the vinyl ester group content (d) was 2 mol%. Moreover, the average particle diameter of PVB-1 was 83 micrometers, and the bulk density was 0.19 g / mL.

(Measurement of degree of acetalization of polyvinyl acetal (a + b mol%), vinyl alcohol group content (c mol%), vinyl ester group content (d mol%))
It measured based on JIS K6728.
(Average particle diameter of aggregated polyvinyl acetal particles)
It measured using the particle size distribution analyzer SALD2200 by Shimadzu Corporation.
(Measurement of bulk density of polyvinyl acetal)
It measured based on JISK6721.

(Introduction amount of crosslinkable functional group)
For the polyvinyl acetal, the introduction amount (b mol%) of the crosslinkable functional group was measured according to the following method. Moreover, a value was calculated | required from the difference of b value calculated | required here and the (a + b) value calculated | required above.
A 2% dimethyl sulfoxide-d6 (containing 0.05 v / v% tetramethylsilane) solution of polyvinyl acetal (PVB-1) was prepared. 1H-NMR was measured at 80 ° C., and the amount (b mol%) of crosslinkable functional groups introduced was calculated from the obtained chart. The chemical shift of the main peak obtained by 1H-NMR measurement of PVB-1 is shown below. The chemical shift is a value when the chemical shift of tetramethylsilane is 0 ppm.
δ = 0.74-0.97 ppm (terminal methyl group proton in butyral ring propyl group of PVB-1)
δ = 0.97 to 1.80 ppm (methylene group proton in the main chain of PVB-1 and methylene group proton in the butyral ring propyl group)
δ = 5.20-5.40 ppm and 5.50-5.70 ppm (CH ₂ = C group proton in methacryl group)

(Residual monomer content)
To the vial, 1 g of polyvinyl acetal (PVB-1) and 10 μL of 0.4% octane / acetone solution as an internal standard were added, headspace gas chromatography was measured, and determined according to the following formula.
(Residual monomer amount) = (Total residual monomer area value) / (Octane area value)

(Evaluation of solvent solubility)
Put 200 mL of ethanol in a 500 mL separable flask and add 6 g of polyvinyl acetal (PVB-1) with stirring at 200 rpm while keeping the temperature at 50 ° C. The time required was measured and evaluated according to the following criteria.
A: Dissolution is completed within 15 minutes.
○: Dissolution completed within 15-30 minutes.
Δ: Dissolution completed in 30 minutes to 2 hours.
X: Dissolution is not completed even after 2 hours.
The dissolution was completed when the solid became invisible.

(Creation of UV cured film)
2 g of polyvinyl acetal (PVB-1) and 0.05 g of 2-hydroxy-4 ′-(2-hydroxyethoxy) -2-methylpropiophenone are dissolved in 50 g of ethanol, and this solution is dissolved in a 10 cm × 10 cm formwork And then dried to obtain a cast film having a thickness of 100 μm. The cast film was peeled off from the mold, and irradiated with UV light (10 times at a speed of 2 meters / minute) with an ultraviolet irradiation device TOSCURE1000 manufactured by Toshiba Corporation to prepare a UV cured film.

(Creation of thermosetting film)
In 50 g of ethanol, 2 g of polyvinyl acetal (PVB-1) and 0.05 g of α, α-azobisisobutyronitrile were dissolved, and this solution was poured into a 10 cm × 10 cm mold and dried to a thickness. A cast film of 100 μm was obtained. This cast film was peeled off from the mold and heat-treated at 80 ° C. for 1 hour to prepare a thermosetting film.

The two kinds of cured films thus obtained were evaluated for solvent resistance according to the following method.
(Evaluation of solvent resistance of cured film)
A cured film (0.3 g) was immersed in 100 g of ethanol and allowed to stand at 50 ° C. for 2 hours. The cured film remaining in ethanol was taken out and weighed (weight of the film before drying). Further, the film taken out was dried at 105 ° C. for 3 hours, and then the weight was measured (the weight of the film after drying), and the degree of swelling and the residual ratio were calculated by the following equations.
(Swelling degree) = (weight of film before drying) / (weight of film after drying) × 100 (%)
(Residual rate) = (weight of film after drying) / (weight of cured film) × 100 (%)

Further, the shape of the cured film remaining in ethanol was visually observed and evaluated according to the following criteria.
(Visual evaluation of remaining cured film)
○: The cured film remains and the shape remains Δ: The cured film remains, but the shape is broken.
X: No cured film remains. Or it remains but is a muddy gel.
The evaluation results are shown in Table 1.

(Evaluation of water absorption of polyvinyl acetal)
Dry (water content: 0.1 wt% or less) 5 g of polyvinyl acetal (PVB-1) was treated under conditions of 40 ° C. and 90% RH for 48 hours. The amount was measured.

(Haze evaluation of polyvinyl acetal film)
After dissolving 1 g of polyvinyl acetal (PVB-1) in 20 g of ethanol, it was cast into a 10 cm × 10 cm mold and dried to obtain a cast film. The haze when this was processed for 48 hours in 40 degreeC and 90% RH atmosphere was evaluated using Huga meter HZ-1 by Suga Test Instruments.

(Preparation of photocrosslinking initiator powder)
After 2-hydroxy-4 '-(2-hydroxyethoxy) -2-methylpropiophenone is sufficiently pulverized with a mixer, it is sieved with a 60 mesh (mesh opening 250 μm) wire mesh to remove particles of 250 μm or more, and photocrosslinking An initiator powder was obtained.
(Preparation of powder coating based on polyvinyl acetal)
The polyvinyl acetal (PVB-1) was sieved using a 60-mesh (mesh size of 250 μm) wire mesh to remove particles of 250 μm or more. 1 g of photocrosslinking initiator powder was added to 100 g of this resin to obtain a powder coating.

(Average particle size of powder paint)
It measured using the particle size distribution analyzer SALD2200 by Shimadzu Corporation.

(Coating of base material using powder paint)
The surface of a 0.8 mm (thickness) × 50 mm × 100 mm stainless steel plate (SAS304) was washed with a detergent and degreased, and then thoroughly washed with ion-exchanged water to obtain a substrate. The base material was coated by a fluidized dipping method using powder paint-1 by the following method.
The powder paint is put into a container equipped with a perforated plate and a cylindrical coating chamber (fluid chamber) (height 50 cm, diameter 30 cm), and air is blown through the perforated plate into the coating chamber to cause the powder paint to flow. It was. The substrate made of the stainless steel plate is preheated (temperature 230 ° C., 10 minutes), suspended in a fluidized layer of powder paint, taken out after 10 seconds, and heated at 230 ° C. for 10 minutes. A painted product was obtained.
(Photocrosslinking of painted materials)
The coated material obtained by the above method was irradiated with UV light (10 times at a rate of 2 meter / minute, UV irradiation device TOSCURE1000 manufactured by Toshiba Corporation) to obtain a photocrosslinked coated material.
(Solvent resistance evaluation of photocrosslinked coatings)
The surface of the photocrosslinked coating product was wiped off five times with gauze impregnated with ethanol, and the state of the coating film at that time was visually confirmed.
○: No change is observed on the coating film surface.
X: Whitening and dissolution of the coating film surface are observed.

(Preparation of ceramic composition and ceramic green sheet (H))
Barium titanate with a particle diameter of 0.1 μm (manufactured by Sakai Chemical Industry Co., Ltd., BT-01), 15 g of ethanol, 15 g of toluene, 1 g of polyvinyl butyral (PVB-1), Marialim AKM (manufactured by NOF Corporation) as a dispersant ) 0.5 g, 1 g of benzylbutyl phthalate as a plasticizer, and 0.01 g of α, α-azobisisobutyronitrile as a crosslinking initiator were placed in a ball mill and mixed at 20 ° C. and 100 rpm for 20 hours to obtain a ceramic composition ( H1) was obtained. This was apply | coated on PET so that the thickness after drying might be set to 25 micrometers, and it dried at 30 degreeC for 5 hours, and obtained the crosslinkable ceramic green sheet (H1). This was heat treated at 90 ° C. for 1 hour to obtain a thermally crosslinked ceramic green sheet (H1).
(Strength evaluation of ceramic green sheet (H))
The obtained ceramic green sheet (H1) was cut into a size of 8 cm × 1 cm, and a tensile test was performed using Shimadzu Autograph, AG-IS, and breaking at 180 ° at a speed of 8 mm / min. As a result, the stress at break was 5.6 N / mm ² .

(Preparation of ceramic composition and ceramic green sheet (P))
Barium titanate with a particle diameter of 0.1 μm (manufactured by Sakai Chemical Industry Co., Ltd., BT-01), 15 g of ethanol, 15 g of toluene, 1 g of polyvinyl butyral (PVB-1), Marialim AKM (manufactured by NOF Corporation) as a dispersant ) 0.5 g, 1 g of benzyl butyl phthalate as a plasticizer, and 0.02 g of 2-hydroxy-4 ′-(2-hydroxyethoxy) -2-methylpropiophenone as a crosslinking initiator are placed in a ball mill and 20 at 100 rpm. Mixing for a time, a ceramic composition (P1) was obtained. This was coated on PET so that the thickness after drying was 25 μm, dried at 40 ° C. for 3 hours, and then dried at 70 ° C. for 5 hours to obtain a crosslinkable ceramic green sheet (P1). This was irradiated with UV light with an ultraviolet irradiation device TOSCURE1000 manufactured by Toshiba Corporation (10 times at a speed of 2 meters / minute) to obtain a photocrosslinked ceramic green sheet (P1).
(Strength evaluation of ceramic green sheet (P))
The obtained ceramic green sheet (H1) was cut into a size of 8 cm × 1 cm, and a tensile test was performed using an autograph AG-IS manufactured by Shimadzu Corporation until breaking at 180 ° at a speed of 8 mm / min. However, the stress at break was 6.0 N / mm ² .

Example 2
In the synthesis of the polyvinyl acetal of Example 1, PVB-2 was obtained in the same manner except that the amount of N- (2,2-dimethoxyethyl) methacrylamide was changed from 110 g to 55 g.
In the same manner as in Example 1, PVB-2, a UV cured film, a thermosetting film, and a photo-crosslinked coating material prepared using a powder coating prepared using PVB-2, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 1.

Example 3
In the synthesis of polyvinyl acetal in Example 1, PVB-3 was obtained in the same manner except that the amount of N- (2,2-dimethoxyethyl) methacrylamide was changed from 110 g to 11 g.
In the same manner as in Example 1, PVB-3, a UV-cured film, a thermosetting film, and a photo-crosslinked coating prepared using a powder coating prepared using PVB-3, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 1.

Example 4
In the synthesis of the polyvinyl acetal of Example 1, the same procedure was performed except that the amount of n-butyraldehyde used was changed from 157 g to 174 g and the amount of N- (2,2-dimethoxyethyl) methacrylamide was changed from 110 g to 22 g. PVB-4 was obtained.
In the same manner as in Example 1, PVB-4, a UV-cured film, a thermosetting film, and a photo-crosslinked coating material prepared using a powder coating prepared using PVB-4, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 1.

Example 5
In the synthesis of the polyvinyl acetal of Example 1, the same procedure was performed except that the amount of n-butyraldehyde used was changed from 157 g to 127 g and the amount of N- (2,2-dimethoxyethyl) methacrylamide was changed from 110 g to 22 g. PVB-5 was obtained.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-5, a UV curable film, a thermosetting film and PVB-5, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 1.

Example 6
In the synthesis of the polyvinyl acetal of Example 2, PVA-2 (polymerization degree 300, saponification degree 88 mol%) was used instead of PVA-1, and the amount of n-butyraldehyde used was changed from 157 g to 140 g. It carried out similarly and obtained PVB-6.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-6, a UV curable film, a thermosetting film and PVB-6, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 1.

Example 7
(Synthesis of aldehyde dimethyl acetal having a crosslinkable functional group)
1 L of acetone was placed in a 2 L separable flask and adjusted to 20 ° C. To this, 98 g of maleic anhydride and 118 g of α-aminoacetaldehyde dimethyl acetal were added and reacted for 8 hours while maintaining at 20 ° C. After completion of the reaction, acetone was distilled off under reduced pressure to obtain 207 g of a crude product. The obtained solid was recrystallized with water / acetone = 1/1 solvent to obtain 143 g of 4- (2,2-dimethoxyethyl) amino-4-oxo-2-cis-butenoic acid.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, the mixture was gradually cooled to 7 ° C. over about 30 minutes with stirring at 120 rpm, and then the solution was kept at 7 ° C. to maintain 128 g of n-butyraldehyde, 4- (2,2-dimethoxyethyl) amino-4-oxo-2. -64 g of cis-butenoic acid and 200 mL of 20% hydrochloric acid were added and the acetalization reaction was carried out for 150 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 150 minutes, and then cooled to room temperature. The precipitated resin was washed with ion exchanged water, neutralized by adding a large excess of aqueous sodium hydroxide at 50 ° C., washed again, and dried to obtain polyvinyl acetal (PVB-7). The degree of acetalization of the obtained polyvinyl acetal (PVB-7) was 63 mol% {degree of acetalization with n-butyraldehyde 56 mol%, 4- (2,2-dimethoxyethyl) amino-4-oxo-2-cis -Degree of acetalization with butenoic acid 7 mol%}, vinyl alcohol group content 35 mol%, vinyl acetate group content 2 mol%. Moreover, the average particle diameter of PVB-7 was 72 micrometers, and the bulk density was 0.18 g / mL.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-7, a UV curable film, a thermosetting film and PVB-7, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

(Measurement of [(Amount of carboxylate group) / (Total amount of carboxyl group and carboxylate group)])
3 g of PVB-7 was dissolved in 100 g of ethanol. Two drops of a phenolphthalein solution were added and titrated with a 0.1 mol / L sodium hydroxide aqueous solution. Subsequently, as a blank sample, 2 drops of a phenolphthalein solution was added to 100 g of ethanol and titrated with a 0.1 mol / L sodium hydroxide aqueous solution. In either case, the end point was the point when the solution became light pink. The difference in the titration amount of the 0.1 mol / L sodium hydroxide solution required for both titrations is defined as titration amount A [mL].
Subsequently, 3 g of PVB-7 was dissolved in 100 g of ethanol, two drops of thymol blue solution were added, and titrated with a 0.1 mol / L aqueous hydrochloric acid solution. Subsequently, as a blank sample, 2 drops of thymol blue solution were added to 100 g of ethanol and titrated with a 0.1 mol / L hydrochloric acid aqueous solution. In either case, the end point was the time when the solution turned from yellow to orange. The difference in the titration amount of the 0.1 mol / L hydrochloric acid aqueous solution required for both titrations is defined as titration amount B [mL].
Calculation was performed according to the following formula. The results are shown in Table 2.
[(Amount of carboxylate group) / (Total amount of carboxyl group and carboxylate group)] = (Titration amount B) / (Titration amount A + Titration amount B)

Example 8
(Synthesis of dimethyl acetal of aldehyde having a crosslinkable functional group)
1 L of tetrahydrofuran was placed in a 2 L separable flask and heated to 60 ° C. To this was added 118 g of 2-hydroxyethyl methacrylate, 128 g of α-chloroacetaldehyde dimethyl acetal, and 5 g of triethylamine, and the reaction was carried out for 8 hours while maintaining the temperature at 60 ° C. After completion of the reaction, tetrahydrofuran was distilled off under reduced pressure, extraction was performed with water / ethyl acetate, and the solvent was distilled off from the obtained organic layer under reduced pressure to obtain 198 g of (2,2-dimethoxyethoxy) ethyl methacrylate.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, the mixture was gradually cooled to 7 ° C. with stirring at 120 rpm, and the solution was kept at 7 ° C., and 157 g of n-butyraldehyde, 72 g of (2,2-dimethoxyethoxy) ethyl methacrylate and 120 mL of 20% hydrochloric acid were added. Was added and the acetalization reaction was carried out for 130 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 200 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-8). The degree of acetalization of the obtained polyvinyl acetal (PVB-8) was 72 mol% (degree of acetalization with n-butyraldehyde 66 mol%, degree of acetalization with (2,2-dimethoxyethoxy) ethyl methacrylate 6 mol%), The vinyl alcohol group content was 26 mol%, and the vinyl ester group content was 2 mol%. Moreover, the average particle diameter of PVB-8 was 88 micrometers, and the bulk density was 0.20 g / mL.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-8, a UV curable film, a thermosetting film and PVB-8, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 9
(Synthesis of aldehydes having crosslinkable functional groups)
1 L of tetrahydrofuran was placed in a 2 L separable flask and heated to 60 ° C. 142 g of glycidyl methacrylate, 90 g of glyoxylic acid and 5 g of triethylamine were added thereto, and the reaction was carried out for 6 hours while maintaining the temperature at 60 ° C. After completion of the reaction, tetrahydrofuran was distilled off under reduced pressure, extraction was performed with water / ethyl acetate, and the solvent was distilled off from the obtained organic layer under reduced pressure to give 2- (3-hydroxy-1-methacryloxy) propyl glyoxylate. 174 g of a mixture of 1- (2-hydroxy-3-methacryloxy) propyl glyoxylate was obtained.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 8 ° C. over 120 minutes with stirring at 120 rpm, the solution was kept at 8 ° C., and 140 g of n-butyraldehyde, 2- (3-hydroxy-1-methacryloxy) propyl glyoxylate and 1 69 g of a mixture of-(2-hydroxy-3-methacryloxy) propyl glyoxylate and 120 mL of 20% hydrochloric acid were added, and the acetalization reaction was performed for 150 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 180 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-9). The degree of acetalization of the obtained polyvinyl acetal (PVB-9) was 67 mol% (degree of acetalization with n-butyraldehyde 61 mol%, 2- (3-hydroxy-1-methacryloxy) propyl glyoxylate and 1- ( 2-hydroxy-3-methacryloxy) propyl glyoxylate has a degree of acetalization of 6 mol%), a vinyl alcohol group content of 31 mol% and a vinyl acetate group content of 2 mol%. Moreover, the average particle diameter of PVB-9 was 79 micrometers, and the bulk density was 0.20 g / mL.
In the same manner as in Example 1, a photocrosslinked coating prepared using a powder coating prepared using PVB-9, a UV curable film, a thermosetting film and PVB-9, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 10
(Synthesis of aldehyde dimethyl acetal having a crosslinkable functional group)
1 L of tetrahydrofuran was placed in a 2 L separable flask and heated to 60 ° C. To this was added 67 g of γ-aminobutyraldehyde dimethyl acetal, 75 g of 2-isocyanatoethyl methacrylate, and 5 g of triethylamine, and the reaction was carried out for 6 hours while maintaining the temperature at 60 ° C. After completion of the reaction, tetrahydrofuran was distilled off under reduced pressure, extraction was performed with water / ethyl acetate, and the solvent was distilled off from the obtained organic layer under reduced pressure to give 1- (4,4-dimethoxybutyl) -3- (2- 138 g of methacryloxyethyl) urea were obtained.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, the mixture was gradually cooled to 8 ° C over about 30 minutes with stirring at 120 rpm, and the solution was kept at 8 ° C to maintain 140 g of n-butyraldehyde, 1- (4,4-dimethoxybutyl) -3- (2-methacrylic acid). 90 g of (roxyethyl) urea and 120 mL of 20% hydrochloric acid were added, and the acetalization reaction was carried out for 150 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 150 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-10). The degree of acetalization of the obtained polyvinyl acetal (PVB-10) was 68 mol% (degree of acetalization with n-butyraldehyde 61 mol%, 1- (4,4-dimethoxybutyl) -3- (2-methacryloxyethyl). ) Degree of acetalization with urea 7 mol%), vinyl alcohol group content 30 mol%, vinyl acetate group content 2 mol%. Moreover, the average particle diameter of PVB-10 was 77 micrometers, and the bulk density was 0.20 g / mL.
In the same manner as in Example 1, a photocrosslinked coating prepared using a powder coating prepared using PVB-10, a UV curable film, a thermosetting film and PVB-10, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 11
(Synthesis of dimethyl acetal of aldehyde having a crosslinkable functional group)
A 2 L separable flask was charged with 1 L of acetone and heated to 60 ° C. To this, 80 g of 2-isocyanatoethyl methacrylate, 62 g of 4-hydroxybenzaldehyde, and 5 g of triethylamine were added, and the reaction was carried out for 8 hours while maintaining the temperature at 60 ° C. After completion of the reaction, acetone was distilled off under reduced pressure to obtain 143 g of N- (4-formylphenoxycarbonyl) -N- (2-acryloxyethyl) amine.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 7 ° C. over about 30 minutes with stirring at 120 rpm, the solution was kept at 7 ° C. and 140 g of n-butyraldehyde, N- (4-formylphenoxycarbonyl) -N- (2-acryloxy) 80 g of ethyl) amine and 120 mL of 20% hydrochloric acid were added, and the acetalization reaction was carried out for 130 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 200 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-11). The degree of acetalization of the obtained polyvinyl acetal (PVB-11) was 66 mol% (the degree of acetalization with n-butyraldehyde was 60 mol%, N- (4-formylphenoxycarbonyl) -N- (2-acryloxyethyl). The degree of acetalization by amine was 6 mol%), the vinyl alcohol group content was 32 mol%, and the vinyl ester group content was 2 mol%. Moreover, the average particle diameter of PVB-11 was 88 micrometers, and the bulk density was 0.20 g / mL.
In the same manner as in Example 1, PVB-11, a UV-cured film, a thermosetting film, and a photo-crosslinked coating material prepared using a powder coating prepared using PVB-11, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 12
(Synthesis of aldehydes having crosslinkable functional groups)
A 2 L separable flask was charged with 1 L of acetone and heated to 60 ° C. To this, 80 g of 2-isocyanatoethyl methacrylate, 62 g of 4-mercaptobenzaldehyde, and 5 g of triethylamine were added, and the reaction was carried out for 8 hours while maintaining the temperature at 60 ° C. After completion of the reaction, acetone was distilled off under reduced pressure to obtain 143 g of N- (4-formylphenylthiocarbonyl) -N- (2-acryloxyethyl) amine.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 7 ° C. over about 30 minutes with stirring at 120 rpm, the solution was kept at 10 ° C. and 158 g of n-butyraldehyde, N- (4-formylphenylthiocarbonyl) -N- (2-acrylic) was obtained. Roxyethyl) amine (90 g) and 20% hydrochloric acid (120 mL) were added, and the acetalization reaction was carried out for 130 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 200 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized with an aqueous sodium hydroxide solution, washed again and dried to obtain polyvinyl acetal (PVB-12). The degree of acetalization of the obtained polyvinyl acetal (PVB-12) was 71 mol% (the degree of acetalization with n-butyraldehyde was 67 mol%, N- (4-formylphenylthiocarbonyl) -N- (2-acryloxyethyl). ) Degree of acetalization by amine 4 mol%), vinyl alcohol group content 27 mol%, vinyl ester group content 2 mol%. Moreover, the average particle diameter of PVB-12 was 84 micrometers, and the bulk density was 0.19 g / mL.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-12, a UV curable film, a thermosetting film and PVB-12, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 13
(Synthesis of aldehyde dimethyl acetal having a crosslinkable functional group)
A 2 L separable flask was charged with 1 L of acetone and heated to 60 ° C. 120 g of decaethylene glycol monomethacrylate, 30 g of α-chloroacetaldehyde dimethyl acetal and 5 g of triethylamine were added thereto, and the reaction was carried out for 8 hours while maintaining the temperature at 60 ° C. After completion of the reaction, acetone was distilled off under reduced pressure to obtain 135 g of decaethylene glycol monomethacrylate mono (2,2-methoxyethyl) ether.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, the mixture was gradually cooled to 7 ° C. over about 30 minutes with stirring at 120 rpm, and the solution was kept at 7 ° C. with 140 g of n-butyraldehyde and 135 g of decaethylene glycol monomethacrylate mono (2,2-methoxyethyl) ether. 120 mL of 20% hydrochloric acid was added, and the acetalization reaction was performed for 130 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 200 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-13). The degree of acetalization of the obtained polyvinyl acetal (PVB-13) was 66 mol% (degree of acetalization with n-butyraldehyde 60 mol%, degree of acetalization with decaethylene glycol monomethacrylate mono (2,2-methoxyethyl) ether. 6 mol%), the vinyl alcohol group content was 32 mol%, and the vinyl ester group content was 2 mol%. Moreover, the average particle diameter of PVB-13 was 80 micrometers, and the bulk density was 0.18 g / mL.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-13, a UV curable film, a thermosetting film and PVB-13, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 14
(Synthesis of aldehyde dimethyl acetal having a crosslinkable functional group)
A 2 L separable flask was charged with 1 L of acetone and heated to 60 ° C. To this was added 115 g of itaconic anhydride, 135 g of γ-aminobutyraldehyde dimethyl acetal, and 5 g of triethylamine, and the reaction was carried out for 8 hours while maintaining the temperature at 60 ° C. After completion of the reaction, acetone was distilled off under reduced pressure to give 4- (2,2-dimethoxybutyl) amino-4-oxo-3-methylene-butanoic acid and 4- (2,2-dimethoxybutyl) amino-4-oxo. 245 g of a mixture of 2-methylene-butanoic acid was obtained.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 7 ° C. over about 30 minutes with stirring at 120 rpm, the solution was kept at 7 ° C. to maintain 140 g of n-butyraldehyde, 4- (2,2-dimethoxybutyl) amino-4-oxo-3. 75 g of a mixture of methylene-butanoic acid and 4- (2,2-dimethoxybutyl) amino-4-oxo-2-methylene-butanoic acid and 120 mL of 20% hydrochloric acid were added, and the acetalization reaction was carried out for 130 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 200 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-14). The degree of acetalization of the obtained polyvinyl acetal (PVB-14) was 66 mol% (degree of acetalization with n-butyraldehyde 61 mol%, 4- (2,2-dimethoxybutyl) amino-4-oxo-3-methylene. -Acetalization degree with a mixture of butanoic acid and 4- (2,2-dimethoxybutyl) amino-4-oxo-2-methylene-butanoic acid 5 mol%), vinyl alcohol group content 32 mol%, vinyl ester group The content was 2 mol%. Moreover, the average particle diameter of PVB-14 was 81 micrometers, and the bulk density was 0.22 g / mL.
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-14, a UV curable film, a thermosetting film and PVB-14, and a ceramic green sheet (H, P) was analyzed and evaluated. Further, [(carboxylate group amount) / (total amount of carboxyl group and carboxylate group)] was measured according to the method described in Example 7. The results are shown in Table 2.

Example 15
(Synthesis of dimethyl acetal of aldehyde having a crosslinkable functional group)
A 2 L separable flask was charged with 1 L of acetone and heated to 60 ° C. To this was added 75 g of glycidyl methacrylate, 100 g of dimethyl acetal terephthalaldehyde, and 5 g of triethylamine, and the reaction was carried out for 8 hours while maintaining the temperature at 60 ° C. After completion of the reaction, acetone was distilled off under reduced pressure to give 2- (3-hydroxy-1-methacryloxy) propyl (4-dimethoxymethyl) benzoate and 1- (2-hydroxy-3-methacryloxy) propyl (4-dimethoxymethyl). 170 g of a mixture of benzoates was obtained.
(Synthesis of polyvinyl acetal)
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 7 ° C. over about 30 minutes with stirring at 120 rpm, the solution is kept at 10 ° C. and 140 g of butyraldehyde, 2- (3-hydroxy-1-methacryloxy) propyl (4-dimethoxymethyl) benzoate And 1- (2-hydroxy-3-methacryloxy) propyl (4-dimethoxymethyl) benzoate (50 g) and 20% hydrochloric acid (120 mL) were added, and the acetalization reaction was carried out for 130 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 200 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-15). The degree of acetalization of the obtained polyvinyl acetal (PVB-15) was 67 mol% (degree of acetalization by n-butyraldehyde 60 mol%, 2- (3-hydroxy-1-methacryloxy) propyl (4-dimethoxymethyl) benzoate And a 1- (2-hydroxy-3-methacryloxy) propyl (4-dimethoxymethyl) benzoate acetalization degree of 7 mol%), vinyl alcohol group content is 31 mol%, vinyl ester group content is 2 mol% Met. Moreover, the average particle diameter of PVB-15 was 75 micrometers, and the bulk density was 0.20 g / mL.
In the same manner as in Example 1, a photo-crosslinked coating product prepared using PVB-15, a UV curable film, a thermosetting film and a powder coating prepared using PVB-15, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 2.

Example 16
Polyvinyl butyral (PVB-16) was obtained in the same manner as in Example 7 except that neutralization with an aqueous sodium hydroxide solution was not performed.
In the same manner as in Example 1, a photo-crosslinked coated product prepared using PVB-16, a UV curable film, a thermosetting film and a powder coating prepared using PVB-16, and a crosslinked ceramic green sheet (H , P) was analyzed and evaluated. Further, [(carboxylate group amount) / (total amount of carboxyl group and carboxylate group)] was measured according to the method described in Example 7. The results are shown in Table 1.

Example 17
50 g of PVB-16 was immersed in 500 g of 0.05% aqueous sodium hydroxide and treated at 50 ° C. for 1 hour, then washed with water and dried to obtain polyvinyl butyral (PVB-17).
In the same manner as in Example 1, a photocrosslinked coating material prepared using PVB-17, a UV curable film, a thermosetting film and a powder coating prepared using PVB-17, and a crosslinked ceramic green sheet (H , P) was analyzed and evaluated. Further, [(carboxylate group amount) / (total amount of carboxyl group and carboxylate group)] was measured according to the method described in Example 7. The results are shown in Table 1.

Example 18
50 g of PVB-16 was immersed in 500 g of a 0.1% aqueous sodium hydroxide solution, treated at 50 ° C. for 1 hour, washed with water and dried to obtain polyvinyl butyral (PVB-18).
In the same manner as in Example 1, a photo-crosslinked coated product prepared using PVB-18, a UV curable film, a thermosetting film and a powder coating prepared using PVB-18, and a crosslinked ceramic green sheet (H , P) was analyzed and evaluated. Further, [(carboxylate group amount) / (total amount of carboxyl group and carboxylate group)] was measured according to the method described in Example 7. The results are shown in Table 1.

Example 19
50 g of PVB-16 was immersed in 500 g of 0.20% sodium hydroxide aqueous solution, treated at 50 ° C. for 1 hour, washed with water and dried to obtain polyvinyl butyral (PVB-19).
In the same manner as in Example 1, a photocrosslinked coating material prepared using a powder coating prepared using PVB-19, a UV cured film, a thermoset film and PVB-19, and a crosslinked ceramic green sheet (H , P) was analyzed and evaluated. Further, [(carboxylate group amount) / (total amount of carboxyl group and carboxylate group)] was measured according to the method described in Example 7. The results are shown in Table 1.

Comparative Example 1
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 8 ° C. over about 30 minutes with stirring at 120 rpm, the solution is kept at 8 ° C., and 161 g of n-butyraldehyde and 120 mL of 20% hydrochloric acid are added, and the acetalization reaction is performed for 150 minutes. It was. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 180 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl butyral (PVB-16). The degree of acetalization of the obtained polyvinyl butyral (PVB-16) was 69 mol% (the degree of acetalization with n-butyraldehyde was 69 mol%), the vinyl alcohol group content was 29 mol%, and the vinyl acetate group content was 2 mol. %Met. Moreover, the average particle diameter of PVB-16 was 79 micrometers, and the bulk density was 0.20 g / mL.
In the same manner as in Example 1, a photocrosslinked coating prepared using PVB-16, a UV curable film, a thermosetting film and a powder coating prepared using PVB-16, and a ceramic green sheet (H, P) was analyzed and evaluated. The results are shown in Table 1.

Comparative Example 2
Into a 5 L glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 3375 g of ion exchange water and 275 g of polyvinyl alcohol (PVA-1) were charged (PVA concentration 7.5%), and the whole was brought to 95 ° C. The solution was completely dissolved by heating. Next, after gradually cooling to 8 ° C over about 30 minutes with stirring at 120 rpm, keep the solution at 8 ° C and add 140 g of n-butyraldehyde, 37 g of 3-cyclohexene-1-carboxaldehyde and 120 mL of 20% hydrochloric acid. The acetalization reaction was performed for 150 minutes. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 180 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water, neutralized by adding an aqueous sodium hydroxide solution, washed again, and dried to obtain polyvinyl acetal (PVB-17). The degree of acetalization of the obtained polyvinyl acetal (PVB-17) was 70 mol% (degree of acetalization with n-butyraldehyde 61 mol%, degree of acetalization with 3-cyclohexene-1-carboxaldehyde 9 mol%), vinyl alcohol The group content was 28 mol%, and the vinyl acetate group content was 2 mol%. The obtained porous powder had an average particle size of 83 μm and a bulk density of 0.20 g / mL.
In the same manner as in Example 1, a coated product prepared using PVB-17, a UV curable film, a thermosetting film and a powder coating prepared using PVB-17, and a ceramic green sheet (H, P) Was analyzed and evaluated. The results are shown in Table 1.

  The polyvinyl acetal of the present invention can be easily cross-linked by UV irradiation, electron beam irradiation, or heat treatment to obtain a cured product having excellent solvent resistance, and thus is useful for various applications requiring solvent resistance. For example, it is useful as a binder for ceramics, a binder for photosensitive materials, a curable ink, an adhesive, a powder paint, a glass interlayer for automobiles or buildings. Of these, it is particularly useful as a powder coating.

Claims (10)

The total amount of the structural units represented by (1) containing at least one of the structural units represented by the general formulas (1) to (4) and calculated based on the amount of ethylene part in the main chain is a mole. %, The total amount of the structural unit represented by (2) is b mol%, the total amount of the structural unit represented by (3) is c mol%, and the total amount of the structural unit represented by (4) is d mol%. The composition ratio among a, b, c, and d is such that a is 40 to 85 mol%, b is 0.1 to 40 mol%, c is 10 to 50 mol%, and d is 0.1 to 30 mol%. %, Polyvinyl acetal.

(However, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ² and R ³ represent a hydrogen atom or a methyl group.)

(However, R ⁴ represents a group containing the functional group represented by the general formula (5) or (6). R ⁵ and R ⁶ represent a hydrogen atom or a methyl group.)

(However, R ⁷ represents a hydrogen atom or a methyl group.)

(However, R ⁸ represents a hydrogen atom or a methyl group. R ⁹ represents a hydrogen atom or a hydrocarbon group having 1 to 9 carbon atoms.)

(Wherein, ^{X 1} is O, it is ^{.R 10} represents a group selected from the group consisting of S and ^{NR 12} represents a hydrogen atom, a methyl _group, a group selected from the group consisting of CH 2 COOR ¹³ and _CH 2 COOM ^1. R ¹¹ represents a hydrogen atom, a group selected from the group consisting of COOR ¹⁴ and COOM ^2. Here, R ¹² , R ¹³ and R ¹⁴ represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and are the same M ¹ and M ² represent either an alkali metal, an alkaline earth metal, or an ammonium group, and may be the same or different.)

(However, X ² represents a group selected from the group consisting of O, S and NR ^16. R ¹⁵ represents COOR ¹⁷ or COOM ^3. R ¹⁶ and R ¹⁷ represent a hydrogen atom or a carbon atom having 1 to 10 carbon atoms. Represents a hydrogen group, which may be the same or different, M ³ represents an alkali metal, alkaline earth metal, or ammonium group.) R ⁴ is a group selected from the group consisting of groups containing a functional group represented by the general formula (5), and in the general formula (5), X ¹ is NR ¹² , R ¹⁰ is a hydrogen atom or a methyl group, The polyvinyl acetal according to claim 1, wherein R ¹¹ is a hydrogen atom. The polyvinyl acetal of Claim 1 or 2 which contains 0.1 mol% or more of carboxyl groups and a carboxylate group in total, and the content ratios satisfy | fill following formula (7).
0 ≦ [Amount of carboxylate group / (total amount of carboxyl group and carboxylate group)] ≦ 0.3 (7) The polyvinyl acetal according to any one of claims 1 to 3, which has an average particle diameter of 30 to 1000 µm and a bulk density of 0.12 to 0.5 g / mL.   The powder coating material containing the polyvinyl acetal in any one of Claims 1-4.   A ceramic binder comprising the polyvinyl acetal according to claim 1.   The ceramic composition containing the polyvinyl acetal in any one of Claims 1-4.   A crosslinkable ceramic green sheet obtained from the ceramic composition according to claim 7.   A ceramic green sheet obtained by heat-treating the crosslinkable ceramic green sheet according to claim 8.   A ceramic green sheet obtained by light-treating the crosslinkable ceramic green sheet according to claim 8.