JP2009221372A - Coating-film forming agent and coating film - Google Patents

Abstract

［一般式（１）において、Ｒ¹、Ｒ²、及びＲ³はそれぞれ独立して水素原子または有機基を示し、Ｘは単結合または結合鎖を示し、Ｒ⁴、Ｒ⁵、及びＲ⁶はそれぞれ独立して水素原子または有機基を示す。］
【選択図】なしThe present invention provides a coating film forming agent having excellent film forming stability and a coating film obtained therefrom.
SOLUTION: It contains a hydrolysis product (A) of a metal alkoxide and a polyvinyl alcohol resin (B) having a 1,2-diol structural unit represented by the following general formula (1). A coating film forming agent is used.
[Chemical 1]

[In General Formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or an organic group, X represents a single bond or a bonded chain, and R ⁴ , R ⁵ , and R ⁶ represent Each independently represents a hydrogen atom or an organic group. ]
[Selection figure] None

Description

  The present invention relates to a film-forming agent using a polyvinyl alcohol-based resin (hereinafter referred to as PVA-based resin), and specifically relates to a film-forming agent having excellent film-forming stability.

Conventionally, a technique for obtaining a barrier laminated film from a composition containing a PVA resin, an alkoxysilane, and a silane coupling agent by a sol-gel method has been proposed (see, for example, Patent Document 1).
In the above technique, first, alkoxysilane is hydrolyzed in an organic solvent with a small amount of water and a catalyst (the hydrolyzate is partially dehydrated and condensed at the same time). Next, the hydrolysis product (and / or condensate) and the PVA resin aqueous solution are mixed to obtain a coating solution. And this coating liquid is apply | coated to a base film, a solvent is removed, and a coating film is obtained.

As described above, metal alkoxide is generally used in the sol-gel method, and an organic solvent (for example, alcohols) is used as the solvent. However, since the PVA resin and the organic solvent are generally incompatible, When an alkoxysilane hydrolysis product solution containing an organic solvent and a PVA-based resin aqueous solution are mixed, impurities such as a gel-like substance are deposited, the system becomes non-uniform, and there is a problem in film formation stability. In particular, in the case of industrial production, there is a problem that strict control is required, quality control is complicated, product standard fluctuation is large, and reproducibility is poor.
Japanese Patent Laid-Open No. 4-345841

  In view of the above problems, an object of the present invention is to provide a coating film forming agent excellent in film forming stability and a coating film obtained therefrom.

  As a result of intensive studies in view of the above circumstances, the present inventor uses a PVA-based resin (B) having a specific structure as a PVA-based resin, and thereby a hydrolysis product (A) of a PVA-based resin and a metal alkoxide. As a result of the marked improvement in the affinity, the object of the present invention was found and the present invention was completed.

［一般式（１）において、Ｒ¹、Ｒ²、及びＲ³はそれぞれ独立して水素原子または有機基を示し、Ｘは単結合または結合鎖を示し、Ｒ⁴、Ｒ⁵、及びＲ⁶はそれぞれ独立して水素原子または有機基を示す。］ That is, the gist of the present invention is that a hydrolysis product (A) of metal alkoxide, alcohol, water, and a polyvinyl alcohol resin (B) having a 1,2-diol structural unit represented by the following general formula (1) (B) ) Is contained in the film-forming agent.

[In General Formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or an organic group, X represents a single bond or a bonded chain, and R ⁴ , R ⁵ , and R ⁶ represent Each independently represents a hydrogen atom or an organic group. ]

  Usually, since a general PVA-based resin is poorly compatible with alcohol, insoluble matters tend to accumulate when the alcohol content is relatively high (for example, 25% by weight or more) in a water / alcohol solvent. On the other hand, the PVA resin (B) having a 1,2-diol structural unit represented by the general formula (1) used in the present invention has a PVA in a water / alcohol mixture due to the influence of the modifying group. The film-forming agent of the present invention contains 1,2-diol structural units even if the system contains a relatively large amount of alcohol, because crystals of the resin are difficult to grow and the ability to hydrate water molecules is strong. The PVA-based resin (B) it has is dissolved stably, and there is a tendency that precipitates such as gels and precipitates do not easily occur.

Hereinafter, the present invention will be described in detail.
The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and is not limited to these contents.

<About hydrolysis product (A) of metal alkoxide>
The metal alkoxide hydrolysis product (A) used in the present invention is a product obtained by hydrolyzing a metal alkoxide. Usually, when a metal alkoxide is hydrolyzed, the alkoxy group is replaced with a hydroxyl group. Since such a product has a property of dehydration condensation reaction between product molecules, the metal alkoxide hydrolysis product (A) usually contains a condensation product obtained by dehydration condensation of the hydrolysis product.

The metal alkoxide is a known general metal alkoxide used in the sol-gel method, and specifically a compound in which at least one alkoxy group is bonded to a metal atom.
The metal atom of such a metal alkoxide is usually silicon, aluminum, titanium, zirconium or the like. Silicon is preferred because the reaction rate is relatively slow and the hydrolysis reaction is easily controlled.
Furthermore, the alkoxy group is usually an aromatic alkoxy group having 6 to 15 carbon atoms such as an aliphatic alkoxy group having 1 to 10 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group, a phenoxy group, or an aryloxy group. It is. From the viewpoint of easy control of the hydrolysis reaction, an aliphatic alkoxy group having 1 to 10 carbon atoms is preferable, and an aliphatic alkoxy group having 1 to 4 carbon atoms is particularly preferable.

  The metal alkoxide may have a functional group other than the alkoxy group. For example, it has an alkyl group such as a methyl group or an ethyl group, an aryl group such as a phenyl group or a benzyl group, a hydroxyl group, an amino group, a mercapto group, a carboxyl group (and its derivatives), a vinyl group, an allyl group, etc. Also good. Among these, an alkyl group having 1 to 4 carbon atoms and an aryl group having 6 to 10 carbon atoms are preferable.

  Specifically, for example, aluminum alkoxides such as trialkoxyaluminates such as trimethoxyaluminate, triethoxyaluminate and tripropoxyaluminate; dialkoxytitanates such as diethyldiethoxytitanate, trialkoxytitanates such as trimethoxytitanate Titanium trialkoxides such as alkyltrialkoxytitanates such as alkyltrialkoxytitanates such as alkyltrialkoxytitanates such as alkyltrialkoxytitanates, trialkoxytitanates such as aryltrialkoxytitanates such as phenyltrimethoxytitanate, tetraalkoxytitanates Is mentioned.

Furthermore, silane alkoxide is mentioned, for example, specifically, monoalkoxysilane, dialkoxysilane, trialkoxysilane, and tetraalkoxysilane.
Specifically, monoalkoxysilanes such as vinyldimethylethoxysilane; dialkyl dialkoxysilanes such as dimethyldimethoxysilane; diaryl dialkoxysilanes; 3-aminopropylmethyldimethoxysilane, 3- [N- (2-aminoethyl) amino An amino group-containing dialkoxysilane such as propylmethyldimethoxysilane; a mercapto group-containing dialkoxysilane such as 3-mercaptopropylmethyldimethoxysilane; a (meth) acryloyl group-containing dialkyl such as 3- (meth) acryloxypropylmethyldimethoxysilane Alkoxysilanes; Alkenyl group-containing dialkoxysilanes such as vinyldimethoxymethylsilane and vinylmethyldiethoxysilane; 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypro Methyl diethoxy silane, dialkoxy silane such as an epoxy group-containing dialkoxysilane such as 3-glycidyloxypropyl ethyl diethoxy silane.

  In addition, alkyltrialkoxysilanes such as trimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane; aryltrialkoxysilanes such as phenyltrimethoxysilane and phenyltriethoxysilane; Amino group-containing trialkoxysilanes such as 2-aminoethyltrimethoxysilane and 2- [N- (2-aminoethyl) amino] ethyltrimethoxysilane; mercapto group-containing trialkoxysilanes such as 3-mercaptopropyltrimethoxysilane; Alkenyl group-containing trialkoxysilanes such as vinyltrimethoxysilane; (meth) acryloyl groups such as 2- (meth) acryloxyethyltrimethoxysilane and 2- (meth) acryloxyethyltriethoxysilane Trialkoxysilanes; (glycidyloxyalkyl) trialkoxysilanes (eg, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2 -Trialkoxysilane containing an epoxy group such as (3,4-epoxycyclohexyl) ethyltriethoxysilane; Trialkoxysilane having an isocyanate group such as γ-isocyanopropyltrimethoxysilane, γ-isocyanopropyltriethoxysilane; Of the trialkoxysilane.

  Furthermore, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane are exemplified.

Among these, silane alkoxides are preferable from the viewpoint of market availability, particularly preferably trialkoxysilanes and tetraalkoxysilanes, particularly preferably trialkoxysilanes and tetraalkoxys having an aliphatic alkoxy group having 1 to 4 carbon atoms. Silane.
Two or more kinds of these metal alkoxides may be used at the same time.

The above metal alkoxide is dissolved in a solvent and hydrolyzed.
As the solvent, aliphatic lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol and propanol are usually used.
A metal alkoxide is 30-1500 weight part normally with respect to 100 weight part of solvents, Preferably it is 50-1000 weight part. If the amount is too small, the hydrolysis reaction tends to be difficult to proceed. If the amount is too large, the hydrolysis reaction rate increases, and the molecular structure of the resulting coating film tends to become three-dimensional, resulting in a low density. There is.

In order to hydrolyze (and / or condense) the metal alkoxide, a catalyst and water are used.
Such catalysts usually include inorganic acid catalysts such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and hydrofluoric acid, and base catalysts such as ammonia. From the viewpoint of precise structure control, an inorganic acid catalyst is preferred.

The amount of such a catalyst is usually 0.001 to 0.3 mol%, preferably 0.002 to 0.2 mol%, particularly preferably 0.003 to 0, based on the total molar amount of alkoxy groups of all metal alkoxides. .1 mol%. When the amount is too small, the hydrolysis reaction tends to be difficult to proceed. When the amount is too large, a porous structure (a three-dimensional network structure and a low density structure is obtained) in which the hydrolysis reaction rate can be increased. ) Are likely to be formed, and the gas barrier properties of the coating film tend to decrease.
Moreover, the quantity of water is 0.8-2 mol% normally with respect to a metal alkoxide, Preferably it is 1-1.5 mol%. When the amount is too small, the hydrolysis reaction is difficult to proceed. When the amount is too large, a porous structure is likely to be formed in the resulting coating film, and the gas barrier property of the coating film tends to be inferior. There is.

  In order to blend the catalyst and water into the metal alkoxide solution, a mixture of the catalyst and water is usually blended at once, but may be added separately.

  The hydrolysis (and / or condensation) reaction of the metal alkoxide is preferably performed at a relatively low temperature. Such temperature is usually 10 to 80 ° C. If the temperature is too high, the hydrolysis reaction rate may increase, and a porous structure is likely to be formed, and the gas barrier property of the coating tends to be inferior. If it is too low, the reaction does not proceed easily. There is a tendency. The reaction is usually carried out with stirring.

  Moreover, although reaction time changes with scales, it is 1-150 hours normally, Preferably it is 1-100 hours. If the time is too long, the viscosity or gelation tends to decrease and the coating property of the coating liquid tends to decrease. If the time is too short, the reaction becomes insufficient and the gas barrier property of the coating film tends to decrease.

［式中、ｎは通常１〜２０の整数であり、Ｒ_iは炭素数１〜４の脂肪族アルキル基もしくは水素原子であり、Ｒ_iiは炭素数１〜４の脂肪族アルコキシ基もしくは水酸基又は炭素数１〜４のアルキル基もしくは炭素数６〜１０のアリール基である。］ As described above, the metal alkoxide is hydrolyzed by the added water, and the resulting hydrolyzate is partially condensed. Also, the corresponding alcohol is generated by hydrolysis.
Such a condensate has a branched shape, a linear shape, etc., but the structure of the coating film formed tends to be densified as it is linear.
One aspect of the hydrolysis-condensation product obtained when the most preferable one of the above metal alkoxides is used is shown below.

Wherein, n is an integer of usually 1 to 20, R _i is an aliphatic alkyl group or a hydrogen atom having 1 to 4 carbon atoms, R _ii is a hydroxyl group or or aliphatic alkoxy group having 1 to 4 carbon atoms An alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms. ]

  In this way, a solution of the metal alkoxide hydrolysis product (A) (and condensate) is obtained. In the present invention, such a solution is preferably used as it is. In some cases, the solution is drained, and the resulting metal alkoxide hydrolysis product (A) (and condensate) is blended in the modified PVA resin (B) solution described below, or the drained solution is dissolved in the solvent again. May be used.

［一般式（１）において、Ｒ¹、Ｒ²、及びＲ³はそれぞれ独立して水素原子または有機基を示し、Ｘは単結合または結合鎖を示し、Ｒ⁴、Ｒ⁵、及びＲ⁶はそれぞれ独立して水素原子または有機基を示す。］ (Component (B) used in the present invention)
In the present invention, the hydrolysis product (A) of the metal alkoxide obtained as described above and the PVA resin (B) having a 1,2-diol structural unit represented by the following general formula (1) are used. The specific modified PVA is used. Such a PVA resin is obtained by copolymerizing a vinyl ester monomer and a monomer that becomes a 1,2-diol structural unit represented by the following general formula (1) and hydrolyzing (saponifying) it. is there.

[In General Formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or an organic group, X represents a single bond or a bonded chain, and R ⁴ , R ⁵ , and R ⁶ represent Each independently represents a hydrogen atom or an organic group. ]

(Structure content of component (B) used in the present invention, adjustment method)
The composition of the PVA resin (B) in the present invention is not particularly limited.
Content of the said structural unit (1) in PVA-type resin (B) is 0.01-20 mol% normally, Preferably it is 1-15 mol%, Most preferably, it is 3-12 mol%. If the content is too small, a stable coating film forming agent tends to be difficult to obtain, and if it is too much, the gas barrier property of the coating film tends to decrease.
Further, in order to adjust the content of the structural unit, it is possible to adjust by blending at least two types of PVA resins (B) having different contents of the structural unit (1). The seed may be a PVA-based resin that does not contain the structural unit (1).

For this way, the PVA-based resin in which the side chain 1,2-glycol bond amount is adjusted, the side chain 1,2-glycol bond content is not safely be calculated in weight average, exactly ¹ H-NMR From these measurement results, the amount of side chain 1,2-glycol bonds can be calculated.

  Furthermore, the degree of saponification of the PVA resin (B) component is usually 85 to 100 mol%, preferably 90 to 100 mol%, particularly preferably 98 to 100%, as measured by a titration method (JIS K6726). When the degree of saponification is too low, the gas barrier properties of the coating film tend to decrease.

  The degree of polymerization of the PVA resin (B) component is usually 100 to 4000, preferably 300 to 3500, and particularly preferably 500 to 2800, as measured by an aqueous solution viscosity measurement method (JIS K6726). If the degree of polymerization is too low, cracks tend to occur in the coating film, and if it is too high, the viscosity tends to be too high and workability tends to decrease.

The organic group in the 1,2-diol structural unit represented by the general formula (1) is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. And saturated hydrocarbon groups such as tert-butyl group, aromatic hydrocarbon groups such as phenyl group and benzyl group, halogen atom, hydroxyl group, acyloxy group, alkoxycarbonyl group, carboxyl group and sulfonic acid group.
R ^{1 to} R ³ are usually a saturated hydrocarbon group or a hydrogen atom having 1 to 30 carbon atoms, particularly 1 to 15 carbon atoms, and more preferably 1 to 4 carbon atoms. R ^{4 to} R ⁵ are preferably an alkyl group having 1 to 30 carbon atoms, particularly 1 to 15 carbon atoms, more preferably 1 to 4 carbon atoms, or a hydrogen atom, and most preferably a hydrogen atom. Particularly preferred are those wherein R ^{1 to} R ⁶ are all hydrogen and X is a single bond.

Moreover, X in the structural unit represented by the general formula (1) is typically a single bond from the viewpoint that the denseness of the molecular structure of the formed coating film is excellent.
In addition, a bond chain may be used as long as the effect of the present invention is not inhibited. Such a bonding chain is not particularly limited, but other than hydrocarbon chains such as alkylene, alkenylene, alkynylene, phenylene, naphthylene (these hydrocarbons may be substituted with halogen such as fluorine, chlorine, bromine, etc.), _{-O -, - (CH 2 O} ) m -, - (OCH 2) m -, - (CH 2 O) m CH 2 - structure containing an ether binding site, such as, -CO -, - COCO -, - CO A structure containing a carbonyl group such as (CH ₂ ) _m CO—, —CO (C ₆ H ₄ ) CO—, a structure containing a sulfur atom such as —S—, —CS—, —SO—, —SO ₂ —, -NR -, - CONR -, - NRCO -, - CSNR -, - NRCS -, - structure comprising NRNR- such as nitrogen atoms, -HPO ₄ - structure containing a hetero atom such as structure containing a phosphorus atom, such as, -Si (OR) _2- , -OSi (OR) _{2 -, - OSi (OR)} 2 O- and the like structures containing a silicon _{atom, -Ti (OR) 2 -,} - OTi (OR) 2 -, - OTi (OR) structure containing ₂ O- such as titanium atoms , -Al (OR)-, -OAl (OR)-, -OAl (OR) O-, and the like include a structure containing a metal atom such as a structure containing an aluminum atom. A hydrogen atom and an alkyl group, and m is a natural number, usually 1 to 30, preferably 1 to 15 and more preferably 1 to 10. Of these, —CH ₂ OCH ₂ — and a hydrocarbon chain having 1 to 10 carbon atoms are preferable from the viewpoint of stability during production or use, and further a hydrocarbon chain having 1 to 6 carbon atoms, particularly 1 carbon atom. It is preferable that

そして、ＰＶＡ系樹脂（Ｂ）の最も好ましい組成は、上記構造単位（１ａ）が３〜１２モル％、およびビニルアルコール由来の構造単位、および残部が酢酸ビニル由来のビニルアセトキシ構造単位からなり、ケン化度９８〜１００％、重合度５００〜２８００であるものである。 The most preferable structure of the PVA resin (B) in the present invention is that in which R ¹ and R ^{2 to} R ⁴ in the structural unit (1) are all hydrogen atoms, and X is a single bond. That is, those containing a structural unit represented by the following structural formula (1a) are preferable.

The most preferable composition of the PVA-based resin (B) is composed of 3 to 12 mol% of the structural unit (1a), a structural unit derived from vinyl alcohol, and the remainder composed of vinyl acetoxy structural unit derived from vinyl acetate. The degree of conversion is 98 to 100% and the degree of polymerization is 500 to 2800.

(Production method of component (B))
Although it does not specifically limit about the manufacturing method of PVA-type resin (B) used by this invention, Taking PVA-type resin (B) containing the structural unit (1a) which is the most preferable structure as an example, [1] As a comonomer 3,4-diol-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-ol-1-butene, 4-acyloxy-3-ol-1-butene, 3,4-diacyloxy- Using 2-methyl-1-butene or the like, copolymerizing these with a vinyl ester monomer to obtain a copolymer, and then saponifying the copolymer, or [2] using vinyl ethylene carbonate or the like as a comonomer These are copolymerized with vinyl ester monomers to obtain a copolymer, which is then saponified and decarboxylated, or [3] 2,2-diene as a comonomer Using alkyl-4-vinyl-1,3-dioxolane, etc., copolymerized with these with a vinyl ester monomer to obtain a copolymer, then saponification, and a method of deacetalization thereof.

  In particular, the polymerization proceeds well, it is easy to introduce 1,2-diol structural units uniformly into the PVA, and the polyvinyl acetate paste before saponification is polymerized even if the modification amount increases to 7-8 mol% or more. The production method [1] is adopted because of the advantages in production that it does not precipitate in the solvent, the problems in melt-molding the obtained PVA, and the final film characteristics. Particularly preferred is a method of saponifying a copolymer obtained by copolymerizing 3,4-diasiloxy-1-butene and a vinyl ester monomer in terms of excellent copolymerization reactivity. Furthermore, it is preferable to use 3,4-diacetoxy-1-butene as 3,4-diacyloxy-1-butene. Moreover, you may use the mixture of these said monomers.

In addition, the reactive ratio of each monomer when vinyl acetate is used as the vinyl ester monomer and 3,4-diacetoxy-1-butene is copolymerized is r (vinyl acetate) = 0.710, r ( 3,4-diacetoxy-1-butene) = 0.701, and in the case of vinyl ethylene carbonate described later, r (vinyl acetate) = 0.85, r (vinyl ethylene carbonate) = 5.4, 3,4-diacetoxy-1-butene is superior in copolymerization reactivity with vinyl acetate.
The chain transfer constant of 3,4-diacetoxy-1-butene is Cx (3,4-diacetoxy-1-butene) = 0.003 (65 ° C.). In the case of vinyl ethylene carbonate, Cx (vinyl Ethylene carbonate) = 0.005 (65 [deg.] C.) and Cx (2,2-dimethyl-4-vinyl-1,3-dioxolane) in the case of 2,2-dimethyl-4-vinyl-1,3-dioxolane = Compared with 0.023 (65 ° C.), it is a hindrance to polymerization and does not easily increase the degree of polymerization or cause a decrease in polymerization rate.

  In addition, such 3,4-diacetoxy-1-butene is the same as that derived from the vinyl acetate structural unit, which is a main structural unit, as a by-product generated when the copolymer is saponified. The fact that there is no need to provide a special device or process is also a great industrial advantage. Further, 3,4-diacetoxy-1-butane, 1,4-diacetoxy-1-butene, 1,4-diacetoxy-1-butane and the like may be contained as a small amount of impurities.

  3,4-diol-1-butene is available from Eastman Chemical Co., and 3,4-diacetoxy-1-butene is commercially available from Eastman Chemical Co. be able to. Further, 3,4-diacetoxy-1-butene obtained as a by-product during the production process of 1,4-butanediol can also be used.

  The PVA having a 1,2-diol structural unit produced by the production methods of [2] and [3] described above has a carbonate ring and a side chain when the degree of saponification is low or when decarboxylation is insufficient. Since the dioxolane ring remains and the resulting coating film structure is lacking in density and inferior in gas barrier properties, it should be used with attention to this.

(Vinyl ester monomer)
Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, Aliphatic vinyl esters such as vinyl trifluoroacetate, and aromatic vinyl esters such as vinyl benzoate, etc., and usually aliphatic groups having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. Vinyl ester. From the economical viewpoint, vinyl acetate is particularly preferably used. These are usually used alone, but a plurality of them may be used simultaneously as necessary.

  In addition, what is necessary is just to determine the weight ratio of the monomer used as the 1, 2-diol structural unit represented by the said General formula (1) at the time of copolymerizing according to the desired introduction amount mentioned above. Moreover, depending on the case, you may copolymerize the ethylenically unsaturated monomer which can be copolymerized in the range which does not inhibit the effect of this invention at the time of copolymerization (for example, 50 mol% or less).

  Moreover, it is preferable to add a known polymerization inhibitor used in radical polymerization to the reaction system at the end of the polymerization. Examples of such polymerization inhibitors include m-dinitrobenzene, ascorbic acid, benzoquinone, and α-methylstyrene. Examples include a monomer, p-methoxyphenol, and sorbic acid.

  The copolymer thus obtained is then saponified, and the resin obtained by solid-liquid separation is dried, whereby the 1,2-diol structural unit represented by the above general formula (1) is obtained. A PVA-based resin (B) is obtained.

Therefore, the PVA resin (B) in the present invention can have a structure derived from partially unsaponified comonomer.
The other part is a vinyl alcohol structural unit and a remaining vinyl ester-derived acyloxy group-containing structural unit (and a small amount of a copolymerizable ethylenically unsaturated monomer structural unit).
The saponification degree in the present invention is a value measured by a titration method (JIS K6726). The ester part of the vinyl ester monomer and the acyloxy part or carbonate of the comonomer corresponding to the 1,2-diol structural unit are used. This means the rate of change (mol%) of the total amount of parts and acetal parts to hydroxyl groups.

  In addition, the PVA-based (B) resin used in the present invention may be a blend of a PVA-based resin containing the structural unit (1) and another PVA-based resin different from the PVA-based resin. Examples of the resin include those having different structural units, those having different saponification degrees, and those having different molecular weights.

The compounding ratio of the hydrolysis product (A) of the metal alkoxide and the modified PVA resin (B) in the present invention is the metal contained in the hydrolysis product (A) of the metal alkoxide with respect to the weight of the modified PVA resin (B). Is 0.005 to 0.12 mol / g, preferably 0.008 to 0.06 mol / g, particularly preferably 0.012 to 0.04 mol / g.
When this value is too small, the strength of the obtained coating film tends to decrease, and when it is too large, the gas barrier property tends to decrease due to insufficient water resistance.

<Method for producing coating film forming agent>
The film-forming agent of the present invention is usually obtained by preparing a solution of the above-mentioned hydrolysis product of metal alkoxide (A) and a specific modified PVA resin (B) solution in advance and mixing both solutions. It is done. In some cases, the solution of the metal alkoxide hydrolysis product (A) contains a specific modified PVA resin (B), or conversely, the solution of the specific modified PVA resin (B) hydrolyzes a metal alkoxide. You may contain a thing (A).

  The solvent of the specific modified PVA resin (B) solution is usually water, but a lower alcohol having 1 to 4 carbon atoms such as methanol and ethanol within a range not impairing the effect of the present invention (for example, 25% by weight or less), An organic solvent such as acetone may be contained.

  In the present invention, by using a specific modified PVA resin (B), when a PVA resin solution and a hydrolysis product (A) solution of a metal alkoxide are blended, a gel-like substance precipitates or impurities are generated. Therefore, the system does not become non-uniform so that the film forming stability is excellent.

  The amount of the metal alkoxide hydrolysis product (A) and the specific modified PVA resin (B) relative to the total amount of the film-forming agent of the present invention (the amount of (A) + (B)) is converted into the amount charged. The amount is usually 1 to 40% by weight, preferably 5 to 40% by weight. If this value is too large, the viscosity tends to be too high and the thickness controllability during coating tends to decrease. If it is too small, the solvent tends to be large and drying tends to take a long time.

Further, the solvent in the coating film forming agent is usually a mixed solvent of an aliphatic alcohol having 1 to 4 carbon atoms and water, and the amount of the alcohol having 1 to 4 carbon atoms in the solvent is usually 0.1 to 70% by weight, preferably Is 3 to 60% by weight, particularly preferably 25 to 55% by weight. When this value is too large, a stable film forming agent cannot be obtained.
Usually, since a general PVA-based resin is poorly compatible with alcohol, insoluble matters tend to accumulate when the alcohol content is relatively high (for example, 25% by weight or more) in a water / alcohol solvent. On the other hand, the side chain 1,2-glycol-modified PVA resin (B) used in the present invention is difficult to grow PVA resin crystals in a water / alcohol mixture due to the influence of the modifying group. The film-forming agent tends to hardly cause precipitates such as gels or precipitates even if the system contains a relatively large amount of alcohol.

  In the coating film forming agent of the present invention, the stirring time after mixing the component (A) and the component (B) is usually 8 hours to 80 hours, preferably 12 hours to 60 hours. If the time is too short, the uniformity of the film-forming agent tends to decrease, and if it is too long, the production efficiency tends to decrease.

<Manufacturing method of coating film>
After applying the coating film forming agent of the present invention on a substrate, a coating film is obtained by removing the solvent.
Such a substrate is usually a film composed of a thermoplastic resin. Examples of such resins include polyolefin resins (for example, polyethylene resins such as polyethylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, ionomer; polypropylene, propylene-ethylene copolymer, propylene-butene- 1 copolymer, propylene-containing propylene resin having a propylene content of 80% by weight or more such as propylene-ethylene-butene-1 copolymer), polyester resin (eg, polyalkylene terephthalate such as polyethylene terephthalate or polybutylene terephthalate, polyethylene-2 , 6-Naphthalate and other polyalkylene naphthalates; liquid crystalline polyesters, etc.), polyamide resins (polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide) / 66, polyamide 66/610, polyamide MXD, etc.), vinyl chloride resin (polyvinyl chloride, etc.), vinylidene chloride resin (vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride- ( (Meth) acrylic acid ester copolymer), styrene resin (polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, etc.), polyvinyl alcohol resin (polyvinyl alcohol, ethylene-vinyl alcohol copolymer). Etc.), polyimide resins (polyimide, polyamideimide, polyetherimide, etc.), polycarbonate resins, polysulfone resins (polysulfone, polyethersulfone, etc.), polyphenylene ether resins, polyphenylene Examples include lensulfide resins (polyphenylene sulfide, etc.), cellulose resins (cellulose ester resins, cellophane, etc.), polyetheretherketone, polyparaxylene, polyacrylonitrile, and the like, and include various components of these resins. A polymer etc. are illustrated. Polyolefin resins, polyester resins, and nylon resins are preferable, and polyester resins are particularly preferable.
These resins may be used alone or in combination of two or more. Further, the substrate may be a single layer, a laminated film composed of a plurality of layers, or a stretched film thereof.

  For the base material, stabilizers (antioxidants, ultraviolet absorbers, light-resistant stabilizers, heat stabilizers, etc.), crystal nucleating agents, flame retardants, flame retardant aids, fillers, plasticizers as necessary , Impact modifiers, reinforcing agents, colorants, dispersants, antistatic agents, foaming agents, antibacterial agents, lubricants (for example, inorganic lubricants such as silica-based fine powder and alumina-based fine powder, polyethylene-based fine powder, acrylic-based) Organic lubricants such as fine powders), hydrocarbon polymers (styrene resins, terpene resins, petroleum resins, dicyclopentadiene resins, coumarone resins such as coumarone indene resins, phenol resins, rosin or derivatives thereof and their Hydrogenated resins, etc.), waxes (higher fatty acid amides, higher fatty acids or salts thereof, higher fatty acid esters, natural waxes such as minerals and plants, synthetic waxes such as polyethylene) Good. These additives can be used alone or in combination of two or more. The surface of the substrate may be subjected to a surface treatment such as a discharge treatment such as corona discharge or glow discharge, an acid treatment such as chromic acid treatment, or a soot treatment.

  The thickness of the substrate can be appropriately selected in consideration of packaging suitability, mechanical strength, flexibility, and the like, and is usually 0.1 to 1000 μm, preferably 1 to 500 μm.

  As a coating method of the film-forming agent of the present invention, generally known methods such as roll coating method, dip coating method, bar coating method, nozzle coating method, die coating method, spray coating method, spin coating method, curtain Various printing methods such as a coating method, a flow coating method, screen printing, gravure printing, and curved surface printing, or a combination of these can be employed.

After coating, the solvent is removed to obtain a coating film.
A solvent removal process is not specifically limited, What is necessary is just to employ | adopt a well-known method. For example, there are normal temperature natural drying and heat drying, and the heating temperature is usually 40 to 200 ° C, preferably 60 to 180 ° C, more preferably 80 to 150 ° C. The drying time is usually 0.5 seconds to 20 hours, preferably 1 minute to 15 hours.

  The thickness of the coating film after drying is usually 0.05 to 20 μm, preferably 0.1 to 15 μm. When this thickness is too high, the coating film is liable to crack.

  The coating film obtained from the coating film forming agent of the present invention comprises a hydrolysis product (A) of a metal alkoxide, a polymer and / or oligomer formed by condensation thereof, and PVA having 1,2-glycol in the side chain It is presumed that the gas barrier property is exhibited when these components react and / or interact with each other.

  As described above, a coating film can be obtained by the coating film forming agent of the present invention. The film-forming agent of the present invention uses a specific modified PVA-based resin (B), so that a gel-like product is deposited even when a hydrolysis product and / or condensate (A) of a metal alkoxide is blended. Impurities in film formation are excellent because impurities do not occur and the system does not become non-uniform.

  The film-forming agent of the present invention uses a specific modified PVA-based resin (B), so that a gel-like product is deposited even when a hydrolysis product and / or condensate (A) of a metal alkoxide is blended. Impurities in film formation are excellent because impurities do not occur and the system does not become non-uniform.

  Moreover, since the coating film obtained from the coating film forming agent of the present invention is excellent in gas barrier properties, the laminated film having the coating film is useful as an electronic member-related material such as a food packaging film or a substrate of a liquid crystal display element.

Example 1
<Hydrolyzed metal alkoxide (A)>
75 parts of tetraethoxysilane, 75 parts of ethanol, 5.5 parts of 2N hydrochloric acid (0.007 mol% hydrochloric acid based on the total moles of tetraethoxysilane and ethoxide groups of phenylethoxysilane added later), 4.7 parts of water And stirred at 80 ° C. for 1 hour (the amount of water is 1.4 mol% based on tetraethoxysilane and phenylethoxysilane to be added later). Next, 7.5 parts of phenylethoxysilane was added and stirred (Liquid A).
<Modified PVA resin (B)>
Containing 6 mol% (measured by ¹ H-NMR) of the above (1a) structural unit, saponification degree of 99.7 mol% measured by titration method (JIS K6726), measured by aqueous solution viscosity measurement method (JIS K6726) The PVA resin having a polymerization degree of 1300 was used and dissolved in water to obtain a 10% by weight resin aqueous solution (liquid B).

A solution (liquid A) of the hydrolysis product of the above metal alkoxide and 165 parts of a solution (liquid B) of the polyvinyl alcohol resin having the 1,2-diol structural unit were mixed.
At this time, the ratio of the hydrolysis product (A) of the metal alkoxide and the modified PVA resin (B) is the ratio of the metal contained in the hydrolysis product (A) of the metal alkoxide to the weight of the modified PVA resin (B). The amount (in terms of moles of metal) was 0.02 mol / g.
This solution was stirred for 24 hours to obtain a film-forming agent. Next, the solution was coated on a corona-treated PET (25 μm) using a bar coater and dried at 150 ° C. for 5 minutes. As a result, a transparent and good laminate having a coating thickness of 4 μm was obtained. .

Example 2
<Hydrolyzed metal alkoxide (A)>
60 parts of tetraethoxysilane, 60 parts of ethanol, 4.5 parts of 2N hydrochloric acid (0.007 mol% of hydrochloric acid with respect to the total moles of tetraethoxysilane and ethoxide groups of phenylethoxysilane to be added later), 3.7 parts of water And stirred at 80 ° C. for 1 hour (the amount of water is 1.4 mol% based on tetraethoxysilane and phenylethoxysilane to be added later). Next, 6 parts of phenylethoxysilane was added and stirred (liquid A).
<Modified PVA resin (B)>
Containing 6 mol% (measured by ¹ H-NMR) of the above (1a) structural unit, saponification degree of 99.7 mol% measured by titration method (JIS K6726), measured by aqueous solution viscosity measurement method (JIS K6726) The PVA resin having a polymerization degree of 1300 was used and dissolved in water to obtain a 10% by weight resin aqueous solution (liquid B).

A solution (solution A) of the hydrolysis product of the metal alkoxide and 132 parts of a solution (solution B) of the polyvinyl alcohol resin having the 1,2-diol structural unit were mixed.
At this time, the ratio of the hydrolysis product (A) of the metal alkoxide and the modified PVA resin (B) is the ratio of the metal contained in the hydrolysis product (A) of the metal alkoxide to the weight of the modified PVA resin (B). The amount (in terms of moles of metal) was 0.02 mol / g.
This solution was stirred for 24 hours to obtain a film-forming agent, and the following evaluation was performed.

<Evaluation>
The film forming agent solution was visually observed for the presence of precipitates such as gel. After that, it was filtered through a pre-weighed wire mesh (# 400 SUS wire mesh), washed with 2 L of water, dried (105 ° C., 3 hours), and the residue remaining on the wire mesh was measured. Precipitates such as gels were calculated.

Comparative Example 1
In Example 2, the PVA-based resin was converted into ordinary unmodified PVA (degree of saponification 99 mol% measured by titration method (JIS K6726), degree of polymerization polymerization degree 1300 measured by aqueous solution viscosity measurement method (JIS K6726)), and The same evaluation was performed in the same manner except that.
The results are shown in Table 1.

*初期仕込み量から、反応により生成するアルコール量を加味し、アルコール含有量の最大値を下記式により算出した。
（初期仕込アルコールの重量＋金属アルコキシドのアルコキシド基が全て完全に加水分解された場合に発生するアルコールの重量）／（初期仕込アルコール量＋金属アルコキシドのアルコキシド基が全て完全に加水分解された場合に発生するアルコール量＋B液中の水量）×１００

* From the initial charge amount, the amount of alcohol produced by the reaction was taken into account, and the maximum value of the alcohol content was calculated by the following formula.
(Weight of initial charge alcohol + weight of alcohol generated when all alkoxide groups of metal alkoxide are completely hydrolyzed) / (Initial charge alcohol amount + when all alkoxide groups of metal alkoxide are completely hydrolyzed) Amount of alcohol generated + amount of water in liquid B) x 100

In Comparative Example 1 using a normal PVA-based resin, a gel-like substance was observed visually because the amount of alcohol in the solvent of the coating film forming agent was large, and the detected insoluble content was as large as 150 ppm. . In such an amount, it is clear that insoluble matter is mixed in the coating film and the gas barrier property is insufficient.
On the other hand, when the modified PVA resin (B) having a 1,2-glycol bond in the side chain is used, the gel-like substance is visually observed even though the amount of alcohol in the solvent is the same. It was not observed, and the insoluble content detected was as small as 15 ppm. In such a trace amount (for example, insoluble content is 20 ppm or less), even if the insoluble content is mixed into the coating film, the degree of reduction in gas barrier properties is not a problem.
Therefore, the advantage of using the modified PVA resin (B) having a 1,2-glycol bond in the side chain of the present invention is clear.

  With the coating film forming agent of the present invention, a gas barrier coating film can be obtained. The coating film forming agent of the present invention uses a specific modified PVA resin (B), so that even when the metal alkoxide hydrolysis product (A) is blended, a gel-like product is precipitated or impurities are generated. As a result, the system does not become non-uniform and the film formation stability is excellent.

Claims (7)

Coating film formation characterized by containing a hydrolysis product (A) of a metal alkoxide and a polyvinyl alcohol resin (B) having a 1,2-diol structural unit represented by the following general formula (1) Agent.

[In General Formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or an organic group, X represents a single bond or a bonded chain, and R ⁴ , R ⁵ , and R ⁶ represent Each independently represents a hydrogen atom or an organic group. ] The amount of metal (number of moles of metal) contained in the hydrolysis product (A) of the metal alkoxide with respect to the weight of the polyvinyl alcohol resin (B) having the 1,2-diol structural unit represented by the general formula (1). The film forming agent according to claim 1, wherein the conversion is 0.005 mol / g to 0.12 mol / g.   The film-forming agent according to claim 1 or 2, wherein the compound (A) is obtained by hydrolyzing a metal alkoxide in the presence of water.   The film-forming agent according to claim 1, wherein the metal alkoxide is a silane alkoxide.   5. The method for producing a film forming agent according to claim 1, wherein a solution of the hydrolysis product (A) of the metal alkoxide and a solution of the polyvinyl alcohol resin (B) are blended.   The coating film obtained from the coating-film formation agent in any one of Claims 1-4.   The laminated body obtained by laminating | stacking the coating film of Claim 4 on the at least single side | surface of a base material.