JP2008280480A - Polyvinyl acetal sheet and its application - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyvinyl acetal sheet which maintains the transparency and the penetration resistance as a laminated glass and has improved adhesion with polyester film, and an interlayer film for laminated glass and a laminated glass. <P>SOLUTION: The polyvinyl acetal sheet is obtained by forming a polyvinyl acetal containing 0.1 to 5 mass% of a specific acrylamide unit in a sheet form. The polyvinyl acetal is preferably one having an average polymerization degree of 150 to 3,500, and containing 8 to 25 mass% of a vinyl alcohol unit, and 0.1 to 15 mass% of an aliphatic acid vinyl ester unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a polyvinyl acetal sheet and a laminated glass using the same.

Laminated glass, which is widely used in various transportations such as automobiles and airplanes, and windows in buildings, usually has two sheets of interlayer film obtained by molding polyvinyl acetal or ethylene vinyl acetate copolymer into a sheet. Between the glass plates.
An intermediate film using an ethylene vinyl acetate copolymer as a material has good adhesion to a polyester film such as polyethylene terephthalate. For this reason, the laminated glass which gave the designability can be obtained by printing a character, a pattern, etc. on a polyester film, and interposing in a laminated glass (for example, refer patent document 1 and patent document 2).

On the other hand, an intermediate film using polyvinyl acetal as a material is more excellent in penetration resistance and adhesiveness to glass than those using an ethylene vinyl acetate copolymer as a material. For this reason, if polyvinyl acetal can be employ | adopted as a material of the intermediate film for laminated glasses to which this design property was provided, a safer and more designable laminated glass will be obtained.
However, since polyvinyl acetal has poor adhesion to the polyester film, there is a risk of delamination at the interface between the polyvinyl acetal and the polyester film when used as a laminated glass. It was.

1994 Patent Publication No. 219762 JP 2004-059395 A

Provided are a polyvinyl acetal sheet having improved adhesion to a polyester film, an interlayer film for laminated glass, and a laminated glass imparted with designability while maintaining transparency and penetration resistance.

The above problems can be solved by a polyvinyl acetal sheet obtained by molding a polyvinyl acetal containing an acrylamide unit having a specific structure in the main chain of the molecule into a sheet.

（式中、Ｒ_１およびＲ_２は炭素数１〜８のアルキル基または水素原子を示し、Ｒ_３は炭素数１〜８のアルキル基、水素原子、（ＣＨ_２）_ｎＳＯ_３Ｈ（ただし０≦ｎ≦５）、またはＣ（ＣＨ_３）_２ＳＯ_３Ｈを示す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ同じものでも異なったものでも良い。）
また、本願の他の発明は、上記のポリビニルアセタールシートと、ポリエステルフィルムを各々一層以上積層させて得られる合わせガラス用中間膜であり、さらに他の発明は、この合わせガラス用中間膜を２枚のガラス板の間に介在させて得られる合わせガラスである。 That is, this invention is a polyvinyl acetal sheet obtained by shape | molding the polyvinyl acetal containing 0.1-5 mass% of acrylamide units represented by general formula (Formula 2) in a sheet form. Here, the polyvinyl acetal preferably has an average degree of polymerization of 150 to 3500, a vinyl alcohol unit of 8 to 25% by mass, and a fatty acid vinyl ester unit of 0.1 to 15% by mass.

(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms or a hydrogen atom, R ₃ represents an alkyl group having 1 to 8 carbon atoms, a hydrogen atom, (CH ₂ ) _n SO ₃ H (provided that 0 ≦ n ≦ 5) or C (CH ₃ ) ₂ SO ₃ H. R ₁ , R ₂ and R ₃ may be the same or different.
Further, another invention of the present application is an interlayer film for laminated glass obtained by laminating one or more of the polyvinyl acetal sheet and the polyester film, and still another invention provides two interlayer films for laminated glass. It is the laminated glass obtained by interposing between the glass plates.

The polyvinyl acetal sheet of the present invention has improved adhesion to a polyester film. When this is used for the interlayer film for laminated glass, laminated glass excellent in transparency and penetration resistance can be obtained. Furthermore, a polyester film can print a character, a pattern, etc. by a well-known method, and the laminated glass which provided the designability is obtained by using this with a polyvinyl acetal sheet.

The polyvinyl acetal sheet is obtained by forming a polyvinyl acetal containing an acrylamide unit having a specific structure in the main chain of a molecule into a sheet shape.

（式中、Ｒ_１およびＲ_２は炭素数１〜８のアルキル基または水素原子を示し、Ｒ_３は炭素数１〜８のアルキル基、水素原子、（ＣＨ_２）_ｎＳＯ_３Ｈ（ただし０≦ｎ≦５）、またはＣ（ＣＨ_３）_２ＳＯ_３Ｈを示す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ同じものでも異なったものでも良い。） The polyvinyl acetal for obtaining a polyvinyl acetal sheet contains 0.1 to 5% by mass of an acrylamide unit represented by the general formula (Formula 3).

(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms or a hydrogen atom, R ₃ represents an alkyl group having 1 to 8 carbon atoms, a hydrogen atom, (CH ₂ ) _n SO ₃ H (provided that 0 ≦ n ≦ 5) or C (CH ₃ ) ₂ SO ₃ H. R ₁ , R ₂ and R ₃ may be the same or different.

Polyvinyl acetal is obtained by acetalizing a polyvinyl alcohol obtained by copolymerizing an acrylamide compound having a specific structure and a fatty acid vinyl ester under an acid catalyst.

The acrylamide compound only needs to have the above structure, and examples thereof include acrylamide, methacrylamide, and 2-acrylamido-2-methylpropanesulfonic acid.

The fatty acid vinyl ester is not particularly limited as long as it is a compound generally used for producing polyvinyl alcohol, and examples thereof include vinyl acetate, vinyl propionate, and vinyl formate.

The ratio of the acrylamide compound and the fatty acid vinyl ester used to obtain polyvinyl alcohol may be appropriately selected according to the degree of saponification of polyvinyl alcohol, the type of aldehyde used in the acetalization reaction, and the composition of the obtained polyvinyl acetal. Although it does not specifically limit, For example, it is good to mix | blend 0.1-8 mass parts of acrylamide compounds with respect to 100 parts of fatty acid vinyl ester.

The polyvinyl alcohol is not particularly limited, but those having an average polymerization degree of 150 to 3500 and a saponification degree of 86 to 99.9 mol% may be used. Moreover, when manufacturing a polyvinyl acetal by the water-medium method, since the handling becomes easy when the polyvinyl alcohol is made into the aqueous solution of 1-15 mass% of density | concentration, it is preferable.

Polyvinyl alcohol may be obtained by copolymerizing another copolymerizable monomer. Examples of other copolymerizable monomers include olefins (ethylene, propylene, etc.), (meth) acrylates (methyl (meth) acrylate, 2-hydroxy (meth) acrylate, glycidyl (meth) acrylate, etc.), Examples include allyl ether (eg, allyl glycidyl ether), vinyl halide compounds (eg, vinyl chloride, vinylidene chloride, vinyl fluoride), vinyl ether (eg, alkyl vinyl ether, 4-hydroxy vinyl ether).
The blending amount of these monomers is preferably 0.5 to 25 parts by mass with respect to 100 parts by mass of the fatty acid vinyl ester. By limiting to this range, the characteristics of these monomers can be expressed while maintaining the characteristics of the obtained polyvinyl alcohol and the polyvinyl acetal obtained by acetalizing the same.

A conventionally well-known thing can be used for the acid catalyst used for acetalization reaction. Although it does not specifically limit, For example, there are hydrochloric acid, nitric acid, sulfuric acid, acetic acid, paratoluenesulfonic acid, and the like. These compounds may be used alone or in combination of two or more.
Although the addition amount of these acid catalysts changes with manufacturing methods and the composition of polyvinyl alcohol to be used, necessary and sufficient acetalization reaction can be advanced by setting it as 1-80 mass parts with respect to 100 mass parts of polyvinyl alcohol.

A conventionally well-known thing can be used for the aldehyde compound used for acetalization reaction. For example, an aldehyde having a chain saturated hydrocarbon group such as formaldehyde, paraformaldehyde, acetaldehyde, paraacetaldehyde, propionaldehyde, butyraldehyde, 2-ethylhexylaldehyde, an aldehyde having a cyclic saturated hydrocarbon group such as cyclohexylaldehyde, furfural, Glyoxal, bifunctional aldehydes such as glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropionaldehyde, etc. There are aldehydes having a group, and these compounds may be used alone or in combination of two or more.
Although the addition amount of these aldehyde compounds changes with manufacturing methods, the saponification degree of raw material polyvinyl acetal, etc. especially in the case of an aqueous medium method, it should just be 50-200 mass parts with respect to 100 mass parts of polyvinyl alcohol. The amount of the vinyl alcohol unit in the obtained polyvinyl acetal can be adjusted by the addition amount of the aldehyde compound.

In the acetalization reaction, an aqueous medium method in which a polyvinyl alcohol aqueous solution, an aldehyde compound and an acid catalyst are mixed and reacted in a reaction system medium to precipitate the formed polyvinyl acetal, and the polyvinyl alcohol is dispersed in an organic solvent to disperse the aldehyde compound and the acid. A solvent method, a homogeneous method, and the like are known, in which a catalyst is mixed and reacted to obtain a polyvinyl acetal solution, and then mixed with a poor solvent to precipitate polyvinyl acetal, and any method may be used.

The average degree of polymerization of the polyvinyl acetal is not particularly limited, but is preferably 150 to 3500. By setting it within this range, the viscosity when the polyvinyl acetal itself is dissolved in a solvent or when melted by heat does not increase, and the penetration resistance of the obtained polyvinyl acetal sheet can be maintained.

The content of the vinyl alcohol unit of the polyvinyl acetal is not particularly limited. However, when the content is in the range of 8 to 25% by mass, the penetration resistance can be improved while maintaining the water resistance of the obtained polyvinyl acetal. it can.

The content of the fatty acid vinyl ester unit of polyvinyl acetal is not particularly limited, but if it is in the range of 0.1 to 15% by mass, the adhesiveness to the polyester film is maintained while maintaining the heat resistance of the obtained polyvinyl acetal. Can be improved.

In order to form polyvinyl acetal into a sheet, it may be processed by a conventionally known molding method. Specifically, polyvinyl acetal is processed by a melt extruder, press molding, blow molding, injection molding, calendar molding, or casting. A method of forming into a sheet shape is used.

The thickness of the polyvinyl acetal sheet is generally about 0.2 to 1.5 mm, and a plurality of polyvinyl acetal sheets are laminated for purposes such as strength improvement, sound insulation, heat insulation, light shielding, and decoration. Can also be used. When laminating polyvinyl acetal sheets, not only sheets having the same composition but also sheets having different compositions may be laminated.

When molding polyvinyl acetal into a sheet, plasticizers, UV absorbers, antioxidants, adhesive strength modifiers, coupling agents, surfactants, thermal stabilizers, infrared absorbers, fluorescents are used as necessary. One or more additives such as a colorant, a colorant, a dehydrating agent, an antifoaming agent, an antistatic agent, and a flame retardant may be added.

As the plasticizer, those usually used as plasticizers for plastics can be used, and ester plasticizers having an ether bond in the molecule are preferably used. Examples of the plasticizer include ethylene glycol-di-2-ethylbutyrate, 1,3-propylene glycol-di-2-ethylbutyrate, 1,4-propylene glycol-di-2-ethylbutyrate, 1, 2-propylene glycol-di-2-ethylbutyrate, diethylene glycol-di-2-ethylbutyrate, diethylene glycol-di-2-ethylhexanoate, diethylene glycol-dicapryate, triethylene glycol-di-2-ethylbutyrate, Examples include triethylene glycol-di-2-ethylhexanoate, triethylene glycol-dicapryate, tetraethylene glycol-di-2-ethylbutyrate, tetraethylene glycol-dicapryate, and the like. These may be used alone or in combination of two or more.
Among these, it is preferable to use triethylene glycol-di-2-ethylbutyrate or triethylene glycol-di-2-ethylhexanoate because the transparency of the obtained polyvinyl acetal sheet can be maintained.

The amount of the plasticizer added to the polyvinyl acetal varies depending on the average degree of polymerization, the degree of acetalization, the amount of residual acetyl groups, and the like, and is not particularly limited, but is 10 to 50 parts by mass of the plasticizer with respect to 100 parts by mass of the polyvinyl acetal. A degree is added. When it is in this range, the penetration resistance of the obtained sheet can be improved while maintaining melt moldability.

As the UV absorber, those usually used for plastics can be used, and examples thereof include benzotriazole UV absorbers, hindered amine UV absorbers, and benzoate UV absorbers. Examples of the benzotriazole ultraviolet absorber include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α′dimethylbenzyl) phenyl] -2H-benzo Triazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole. Examples of hindered amine ultraviolet absorbers include 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis (1,2,2). , 6,6-pentamethyl-4-piperidyl) -2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl malonate, 4- (3- (3,5-di) -T-butyl-4-hydroxyphenyl) propionyloxy) -1- (2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl) -2,2,6 6-tetramethylpiperidine and the like. Examples of benzoate ultraviolet absorbers include 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate and so on. These ultraviolet absorbers can be used alone or in combination of two or more.

The compounding quantity of a ultraviolet absorber is 10-100,000 ppm on the mass reference | standard with respect to polyvinyl acetal, Preferably it is the range of 100-10000 ppm. When it is in this range, the light resistance of the obtained sheet can be improved while suppressing the production cost.

Antioxidants include, for example, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants are preferable, and alkyl-substituted phenolic antioxidants are particularly preferable. .

Examples of phenolic antioxidants include alkyl-substituted phenolic compounds, acrylate compounds, and triazine group-containing phenolic compounds. Examples of the alkyl-substituted phenol compound include 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, and octadecyl-3- (3,5-) di- t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis (4-methyl-6-tert-butylphenol) 4,4′-butylidene-bis (6-tert-butyl-m-cresol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), bis (3-cyclohexyl-2-hydroxy-5) -Methylphenyl) methane, 3,9-bis (2- (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5- Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxy) Phenyl) propionate) methane, triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate) and the like. Examples of the acrylate compound include 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t-amyl-6- ( 1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate. Examples of the triazine group-containing phenol compound include 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bis-octylthio-1,3,5-triazine, 6- (4-hydroxy- 3,5-dimethylanilino) -2,4-bis-octylthio-1,3,5-triazine, 6- (4-hydroxy-3-methyl-5-t-butylanilino) -2,4-bis-octylthio -1,3,5-triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine.

Examples of phosphorus antioxidants include monophosphite compounds and diphosphite compounds. Monophosphite compounds include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2-t-butyl-4 -Methylphenyl) phosphite, tris (cyclohexylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, 9,10-dihydro-9-oxa-10-phosphat Phenanthrene-10-oxide, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9 , 10-Dihydro-9-oxa-10-phosphine There is such as phenanthrene. Examples of the diphosphite compound include 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite), 4,4′-isopropylidene-bis (phenyl-di-alkyl ( C12-C15) phosphite), 4,4′-isopropylidene-bis (diphenylmonoalkyl (C12-C15) phosphite), 1,1,3-tris (2-methyl-4-di-tridecyl phosphite) -5-t-butylphenyl) butane, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene phosphite. Of these, monophosphite compounds are preferred.

Examples of the sulfur-based antioxidant include dilauryl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, lauryl stearyl 3,3′-thiodipropionate, pentaerythritol-tetrakis- (Β-lauryl-thiopropionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane.

These antioxidants can be used alone or in combination of two or more. The compounding quantity of antioxidant is 0.001-5 mass parts with respect to 100 mass parts of polyvinyl acetals, Preferably it is the range of 0.01-1 mass part. Within this range, while suppressing the production cost, the deterioration of acid value due to thermal deterioration during melt molding and contact with the outside air is prevented, and even when used in laminated glass, the transparency is rarely lowered.

Although it does not specifically limit as an adhesive force regulator, For example, the alkali metal salt or alkaline-earth metal salt of organic acid, the alkali metal salt or alkaline-earth metal salt of inorganic acid, modified silicone oil, etc. are mentioned.
Examples of the organic acid include carboxylic acids such as octylic acid, hexyl acid, butyric acid, acetic acid, and formic acid. These organic acids may be used alone or in combination of two or more. Examples of inorganic acids include hydrochloric acid and nitric acid. These inorganic acids may be used alone or in combination of two or more.

Examples of the alkali metal salt or alkaline earth metal salt of organic acid or inorganic acid include potassium salt, sodium salt, magnesium salt of organic acid or inorganic acid. Alkali metal salts or alkaline earth metal salts of these organic acids and inorganic acids may be used alone or in combination of two or more.

Among the alkali metal salts or alkaline earth metal salts of organic acids and inorganic acids, alkali metal salts or alkaline earth metal salts of organic acids having 2 to 16 carbon atoms are preferably used. In particular, a potassium salt or magnesium salt of a carboxylic acid having 2 to 16 carbon atoms is more preferably used. Examples of the alkali metal salt or alkaline earth metal salt of a carboxylic acid having 2 to 16 carbon atoms include potassium acetate, magnesium acetate, potassium propionate, magnesium propionate, potassium 2-ethylbutanoate, 2-ethylbutanoate magnesium, -Potassium ethylhexylate, magnesium 2-ethylhexylate, etc.
These potassium salts and magnesium salts of carboxylic acids having 2 to 16 carbon atoms may be used alone or in combination of two or more.

The blending amount of the alkali metal salt or alkaline earth metal salt of the organic acid or inorganic acid is not particularly limited, but is 0.0001 to 1 part by mass, preferably 0.001 to 100 parts by mass of the polyvinyl acetal. It is 001-0.5 mass part, More preferably, it is 0.01-0.2 mass part.
Within this range, it becomes possible to adjust the adhesiveness of the sheet without impairing the transparency.

The modified silicone oil may generally be obtained by reacting a compound to be modified with polysiloxane, such as epoxy-modified silicone oil, ether-modified silicone oil, ester-modified silicone oil, amine-modified silicone oil, carboxyl-modified. Examples include silicone oil. These may be used alone or in combination of two or more.

The molecular weight of these modified silicone oils is not particularly limited, but the molecular weight is in the range of 800 to 5000, preferably 1500 to 4000. By setting it as this range, compatibility with polyvinyl acetal can be maintained and it can disperse | distribute uniformly on a sheet | seat. Although the compounding quantity of modified silicone oil is not specifically limited, It is 0.01-0.2 mass part with respect to 100 mass parts of polyvinyl acetals, Preferably it is 0.03-0.1 mass part. By setting it as this range, the adhesive force of the sheet can be adjusted while maintaining good compatibility with polyvinyl acetal.

By embossing the surface of the polyvinyl acetal sheet, it is possible to prevent the sheets from blocking each other during winding after film formation. When a sheet is used as the interlayer film for laminated glass, there is an effect of expelling unnecessary air remaining between the glass and the sheet. A conventionally known embossing depth and shape may be used.

The polyester film is obtained by forming a conventionally known polyester resin into a film shape, and if necessary, it is colored, decorated with gravure printing or flexographic printing, and further dry laminate or extrusion laminate. What has been applied can be used.

The polyester resin is a resin obtained by dehydration condensation of a generally used polycarboxylic acid and a polyol. Although not particularly limited, for example, there are polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like. In addition, as the polyester resin used in the present invention, those subjected to surface treatment by chemical treatment such as chemical treatment or physical treatment such as corona treatment can be used.

The interlayer film for laminated glass is obtained by laminating a polyvinyl acetal sheet on at least one surface of a polyester film.

As a method of laminating the polyvinyl acetal sheet and the polyester film, it may be produced by a conventionally known molding method. Specifically, the polyvinyl acetal and the polyester film are extruded laminate, dry laminate, hot melt laminate, heat seal, What is necessary is just to perform by the casting method.

The interlayer film for laminated glass is made by laminating a polyvinyl acetal sheet on one side of the polyester film, laminating a polyvinyl acetal sheet on both sides of the polyester film, and a polyvinyl acetal sheet on one side of the polyester film. And a sheet of ethylene vinyl acetate copolymer laminated on the other surface.
Among these, what laminated | stacked the polyvinyl acetal sheet on both surfaces of the polyester film is preferable. The polyvinyl acetal sheet is excellent not only in the polyester film but also in the adhesive strength with glass. By making the surface of the interlayer film for laminated glass that comes into contact with the glass into a polyvinyl acetal sheet, the laminated glass is more excellent in penetrability. Is obtained.

Laminated glass is obtained by laminating glass on both sides of an interlayer film for laminated glass. In order to obtain laminated glass, glass and an interlayer film for laminated glass may be laminated by a conventionally known method.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited only to these examples.

Example 1
(Synthesis of polyvinyl acetal)
Into a 3 L dissolution tank equipped with a stirrer was charged 1800 g of pure water, 200 g of polyvinyl alcohol having an average polymerization degree of 1700, a saponification degree of 88.4 mol% and an acrylamide modification amount of 1.9 mol%, and heated to dissolve to dissolve 10 mass% of acrylamide. A modified polyvinyl alcohol aqueous solution was obtained.

Prepare a cylindrical glass container with a capacity of 500 ml that has three supply ports at the bottom of the reactor and one discharge port at the top of the reactor. The reactor is filled with pure water, stirred with an anchor blade, and the internal temperature Was maintained at 40 ° C, and an acrylamide-modified polyvinyl alcohol aqueous solution was introduced into the reactor from the bottom of the reactor at a feed rate of 1840 g / hr, 35 mass% hydrochloric acid 100 g / hr, acetaldehyde 37 g / hr, butyraldehyde 41 g / hr. In parallel, the reaction solution overflowed and was discharged from the upper part of the reactor. The discharged reaction liquid was sent to a separately prepared 4 L aging tank (transfer amount 2.5 L), 190 g of 35 mass% hydrochloric acid was added to the aging tank, and then the aging reaction was performed at 55 ° C. for 4 hours.

A sodium hydroxide aqueous solution was added to the reaction product after aging, and the pH was adjusted to 7 to stop the acetalization reaction. The reaction product after neutralization was cooled to room temperature and then filtered through a centrifuge. The filter cake was diluted with 20 mass times distilled water with respect to the resin content and filtered again three times, and then dried to obtain polyvinyl acetal.

The obtained polyvinyl acetal has a vinyl alcohol unit of 13.3% by mass, a vinyl acetate unit of 13.8% by mass, an acrylamide unit content of 1.7% by mass, and an acrylic acid modified by hydrolysis of the acrylamide unit. The amount was 0.4% by mass, and the degree of acetalization was 70.8% by mass.

(Preparation of polyvinyl acetal sheet)
100 parts by mass of the obtained polyvinyl acetal resin powder and 38 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer were mixed in a mortar, and then heated to 180 ° C. with a press regulated by a spacer. And a polyvinyl acetal sheet having a thickness of 0.76 mm was obtained.

(Preparation of interlayer film)
The obtained polyvinyl acetal sheet was laminated on each side of a 50 μm thick polyethylene terephthalate film (untreated surface), heated and pressurized to 180 ° C. with a press regulated by a spacer, and a thickness of 1.52 mm. An interlayer film was obtained.

(Production of laminated glass)
The interlayer film was sandwiched between two square float glasses having a thickness of 2 mm and a side length of 300 mm, and pre-pressed by a roll method. Subsequently, it pressure-bonded for 30 minutes with the pressure of 12 kg / cm < ² > with the autoclave of 140 degreeC, and the laminated glass was obtained.

The following evaluation was performed about the obtained polyvinyl acetal sheet, the intermediate film, and the laminated glass.

(Evaluation of polyvinyl acetal sheet)
On one surface of the polyvinyl acetal sheet, a 50 μm thick polyethylene terephthalate film (untreated surface) was heated and pressed at 180 ° C. with a press regulated by a spacer to obtain a sheet having a thickness of 0.76 mm. A rectangular test piece of 25 mm × 40 mm was punched out from this sheet, and a tensile test was performed under the conditions of 20 ± 2 ° C. and a tensile speed of 500 mm / min, and 90 ° peel adhesive strength was measured.
In the test piece of Example 1, the 90 ° peel adhesive strength was 100 gf / mm or more, and the polyethylene terephthalate film was firmly bonded so as to break during the measurement.

(Evaluation of interlayer film)
The laminated state and hue of the obtained interlayer film were visually observed.
The test piece of Example 1 was integrated and transparent.

(Evaluation of laminated glass)
(1) Appearance The laminated state and hue of the obtained laminated glass were visually observed.
The test piece of Example 1 was integrated and transparent.
(2) Pummel test After adjusting the obtained laminated glass at a temperature of −18 ° C. ± 0.6 ° C. for 16 hours, it was pulverized with a round porridge having a head of 0.45 kg until the particle size of the glass became 6 mm or less. The degree of peeling at the interface is indicated by the Pummel value.
Pummel value is 8 when the degree of peeling is 2% or less, 7 when 2-5%, 6 when 5-10%, 5 when 10-20%, 4 when 20-40% , 40-60% is evaluated as 3, 60-85% as 2, 2, 85-90% as 1, 90-100% as 0, Pummel 3-8 The others were rejected.
The test piece of Example 1 had a Pummel value of 6, and passed.
(3) Penetration resistance test Penetration resistance of the laminated glass is measured in accordance with JIS R 3212 by measuring the falling ball height (m) at which the test piece can prevent a 2.26 kg steel ball that has been dropped freely. did. A falling ball height of 4 m or more was accepted and less than that was rejected.
The test piece of Example 1 was a pass test with a penetration resistance test result of 4 m or more.

Example 2
An acrylamide-modified polyvinyl alcohol having an average degree of polymerization of 2100, a degree of saponification of 97.1 mol%, and an acrylamide modification amount of 0.8 mol% was used. Acetaldehyde was 92 g / hr, and polyvinyl acetal was obtained in the same manner as in Example 1 without adding hydrochloric acid to the aging can. The obtained polyvinyl acetal has 16.5% by mass of vinyl alcohol units, 2.5% by mass of vinyl acetate units, 0.6% by mass of acrylamide units, and acrylic acid modified by hydrolysis of acrylamide units. The amount was 0.3% by mass, and the degree of acetalization was 80.1% by mass.
A polyvinyl acetal sheet was prepared in the same manner as in Example 1, and the adhesion was evaluated. As a result, it was 40 gf / mm. Moreover, when the intermediate film and the laminated glass were created similarly to Example 1, the obtained intermediate film and the laminated glass were integrated and were transparent. The pummel value of the laminated glass was 7, and the penetration resistance was 4 m or more.

Example 3
An acrylamide-modified polyvinyl alcohol having an average polymerization degree of 800, a saponification degree of 97.8 mol%, and an acrylamide modification amount of 0.3 mol% was used. Polyvinyl acetal was obtained in the same manner as in Example 1, except that acetaldehyde was 69 g / hr, butyraldehyde was 30 g / hr, and 200 g of hydrochloric acid was added to the aging can. The obtained polyvinyl acetal is 10.9% by mass of vinyl alcohol units, 1.6% by mass of vinyl acetate units, 0.3% by mass of acrylamide units, and acrylic acid modified by hydrolysis of acrylamide units. The amount was 0.1% by mass, and the degree of acetalization was 87.1% by mass.
A polyvinyl acetal sheet was prepared in the same manner as in Example 1, and the adhesion was evaluated. The result was 25 gf / mm. Moreover, when the intermediate film and the laminated glass were created similarly to Example 1, the obtained intermediate film and the laminated glass were integrated and were transparent. The pummel value of the laminated glass was 6, and the penetration resistance was 4 m.

Example 4
Using acrylamide-modified polyvinyl alcohol having an average degree of polymerization of 800, a degree of saponification of 90.3 mol%, and an acrylamide modification amount of 1.4 mol%, the raw material supply to the reactor was 1780 g / hr of acrylamide-modified polyvinyl alcohol aqueous solution, 152 g / hr of 35 mass% hydrochloric acid The test was conducted in the same manner as in Example 1 except that acetaldehyde was 68 g / hr and butyraldehyde was 19 g / hr, and 350 g of hydrochloric acid was added to the aging can. The obtained polyvinyl acetal has 10.9% by mass of vinyl alcohol units, 12.1% by mass of vinyl acetate units, 1.2% by mass of acrylamide units, and acrylic acid modified by hydrolysis of acrylamide units. The amount was 0.5% by mass, and the degree of acetalization was 87.1% by mass.
A polyvinyl acetal sheet was prepared in the same manner as in Example 1 and evaluated for adhesion. As a result, it was 100 gf / mm or more, and the polyethylene terephthalate film was broken during the measurement. Moreover, when the intermediate film and the laminated glass were created similarly to Example 1, the obtained intermediate film and the laminated glass were integrated and were transparent. The pummel value of the laminated glass was 5, and the penetration resistance was 4 m.

Comparative Example 1
Polyvinyl alcohol having an average degree of polymerization of 2050, a degree of saponification of 98.2 mol%, unmodified acrylamide, and a raw material supply to the reactor were 1880 g / hr of polyvinyl alcohol aqueous solution, 300 g / hr of 35 mass% hydrochloric acid, 48 g / hr of acetaldehyde, butyl The test was conducted in the same manner as in Example 1 except that aldehyde was 52 g / hr and hydrochloric acid 150 g was added to the aging can. The obtained polyvinyl acetal had a vinyl alcohol unit of 14.9% by mass, a vinyl acetate unit of 1.6% by mass, and an acetalization degree of 83.5% by mass.
A polyvinyl acetal sheet was prepared in the same manner as in Example 1 and the adhesion was evaluated. As a result, it was 10 gf / mm or less. In addition, an interlayer film and a laminated glass were prepared in the same manner as in Example 1. The laminated glass had a Pummel value of 2 and a penetration resistance of 4 m or more. In the laminated glass sample after the evaluation test, peeling occurred at the interface between the polyethylene terephthalate film and the polyvinyl acetal sheet.

Comparative Example 2
Polyvinyl alcohol having an average degree of polymerization of 1700, a degree of saponification of 98.4 mol%, and no acrylamide modification was used. The test was conducted in the same manner as in Example 1 except that hydrochloric acid was not added to the aging can. The obtained polyvinyl acetal had a vinyl alcohol unit of 17.9% by mass, a vinyl acetate unit of 1.5% by mass, and an acetalization degree of 80.6% by mass.
A polyvinyl acetal sheet was prepared in the same manner as in Example 1 and the adhesion was evaluated. As a result, it was 10 gf / mm or less. In addition, an interlayer film and a laminated glass were prepared in the same manner as in Example 1. The laminated glass had a Pummel value of 2 and a penetration resistance of 4 m or more. In the laminated glass sample after the evaluation test, peeling occurred at the interface between the polyethylene terephthalate film and the polyvinyl acetal sheet.

Comparative Example 3
Using itaconic acid-modified polyvinyl alcohol having an average polymerization degree of 1700, a saponification degree of 98.4 mol%, and an itaconic acid-modified 0.8 mol%, the raw material supply to the reactor was 1810 g / hr of a polyvinyl alcohol aqueous solution, 100 g / hr of 35 mass% hydrochloric acid, The test was conducted in the same manner as in Example 1 except that acetaldehyde was 80 g / hr and butyraldehyde was 80 g / hr, and 500 g of hydrochloric acid was added to the aging can. The obtained polyvinyl acetal had a vinyl alcohol unit of 13.0% by mass, a vinyl acetate vinyl ester unit of 14.0% by mass, and an acetalization degree of 73.0% by mass.
A polyvinyl acetal sheet was prepared in the same manner as in Example 1 and the adhesion was evaluated. As a result, it was 10 gf / mm or less. In addition, an interlayer film and a laminated glass were prepared in the same manner as in Example 1. The laminated glass had a Pummel value of 1 and a penetration resistance of 4 m or more. In the sample after the laminated glass evaluation test, peeling occurred at the interface between the polyethylene terephthalate film and the polyvinyl acetal sheet.

Comparative Example 4
Using an ethylene vinyl acetate copolymer sheet having a thickness of 0.76 mm, the adhesiveness with the polyethylene terephthalate film was evaluated in the same manner as in Example 1. As a result, it showed 100 gf / mm or more. It broke. Moreover, the interlayer film was created similarly to Example 1 and the laminated glass was created. The pummel value of the laminated glass was 3, and the penetration resistance was 2 m.

Claims (4)

A polyvinyl acetal sheet obtained by molding a polyvinyl acetal containing 0.1 to 5% by mass of an acrylamide unit represented by the general formula (Chemical Formula 1) into a sheet shape.

(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms or a hydrogen atom, R ₃ represents an alkyl group having 1 to 8 carbon atoms, a hydrogen atom, (CH ₂ ) _n SO ₃ H (provided that 0 ≦ n ≦ 5) or C (CH ₃ ) ₂ SO ₃ H. R ₁ , R ₂ and R ₃ may be the same or different. The polyvinyl acetal contains an average degree of polymerization of 150 to 3500, 8 to 25% by mass of vinyl alcohol units, and 0.1 to 15% by mass of fatty acid vinyl ester units. Polyvinyl acetal sheet. An interlayer film for laminated glass obtained by laminating the polyvinyl acetal sheet according to claim 1 or 2 on at least one surface of a polyester film. A laminated glass obtained by interposing the interlayer film for laminated glass according to claim 3 between two glass plates.