JP5469289B1 - Multilayer film and interlayer film for laminated glass comprising the same - Google Patents

Abstract

A layer containing polyvinyl acetal (I) having an acetalization degree of 55 to 80 mol% and a vinyl ester monomer unit content of 0.1 to 1.5 mol%, an ultraviolet absorber, and a plasticizer ( X), polyvinyl acetal (II) having a degree of acetalization of 70 to 85 mol% and a vinyl ester monomer unit content of 5 to 15 mol%, heat ray shielding fine particles, surfactant, alkali metal salt, and And / or an alkaline earth metal salt and a layer (Y) containing a plasticizer, and the layers (X) are arranged on both outer sides of the layer (Y), and the polyvinyl acetal (I) and the polyvinyl acetal (II) Is a multilayer film satisfying the following formulas (1) and (2).
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)
Thus, a film having sufficient heat ray shielding properties and sound absorbing properties, little coloring due to heating, little foreign matter (undissolved content), and excellent recyclability is provided.

Description

  The present invention relates to a multilayer film having heat ray shielding properties and sound insulation properties. The present invention also relates to an interlayer film for laminated glass comprising the multilayer film, and a laminated glass using the interlayer film. Furthermore, this invention relates to the manufacturing method of the film using the recovered material of the said multilayer film.

  Polyvinyl acetal is obtained by an acetalization reaction in water under acidic conditions using polyvinyl alcohol (hereinafter sometimes abbreviated as “PVA”) and an aldehyde compound. Polyvinyl acetal films are used in various applications because they are tough and have a unique structure that has both hydrophilic hydroxy groups and hydrophobic acetal groups. Various polyvinyl acetals have been proposed. Yes. Among them, polyvinyl formal produced from PVA and formaldehyde, polyvinyl acetal in a narrow sense produced from PVA and acetaldehyde, and polyvinyl butyral produced from PVA and butyraldehyde occupy commercially important positions.

  In particular, polyvinyl butyral is widely used as an interlayer film for laminated glass of automobiles and buildings, and occupies a particularly important position commercially.

  On the other hand, polyvinyl acetal has a problem that it is easy to be colored by heating; a foreign substance (undissolved part) is easily generated in the film of polyvinyl acetal. Various proposals have been made to solve these problems.

  Patent Documents 1 and 2 describe a method for suppressing coloring of polyvinyl acetal by acetalization at a specific hydroxide ion concentration under high temperature and high pressure. Patent Document 3 describes a method of suppressing coloring of the obtained polyvinyl acetal by adding a reducing agent after neutralization by acetalization reaction. However, foreign matter was likely to be generated in the film produced using the polyvinyl acetal obtained by the methods described in Patent Documents 1 to 3. Patent Document 4 describes a method of suppressing the generation of coarse particles by adjusting the concentration of the obtained resin particle slurry in the neutralization reaction after the acetalization reaction. Patent Document 5 describes a method for suppressing the generation of coarse particles by defining the relationship between an acid catalyst and a surfactant used in the acetalization reaction. However, foreign matters were likely to be generated in the film produced using the polyvinyl acetal obtained by the methods described in Patent Documents 4 and 5. Moreover, the film was easily colored by heating. For these reasons, there is a strong demand for polyvinyl acetals in which all the above-mentioned problems are solved.

  In recent years, various highly functional products have been developed for use in interlayer films for laminated glass. For example, for the purpose of imparting high sound insulation performance and heat insulation performance to the interlayer film for laminated glass, a plurality of polyvinyl acetal layers having different content ratios of polyvinyl acetal and plasticizer are laminated, and the central layer is made of heat ray shielding particles. An interlayer film for laminated glass is disclosed (for example, see Patent Documents 6 to 9). In the interlayer film for multi-layer laminated glass, generally, polyvinyl acetals having different average residual hydroxyl groups are used for each layer in order to make the amount of plasticizer contained in each layer different.

  By the way, the interlayer film for laminated glass is generally manufactured using an extruder from the viewpoint of production cost. And the said interlayer film for laminated glass is produced by a coextrusion method. When producing an interlayer film for laminated glass using these methods, a certain amount of trim material is generated at the edge of the film, and there are also off-spec products that are difficult to use as products due to non-uniform composition and thickness. can get.

  When recycling an intermediate film trim for single-layer laminated glass or off-spec products, there are problems that the resulting film is colored by heating and that foreign matter (undissolved part) is generated in the obtained film. On the other hand, when recycling trim and off-spec products for multi-layer laminated glass with different compositions in each layer, in addition to these problems, each component is difficult to be compatible, so there is a problem that transparency is lowered. there were. In particular, when recycling the interlayer film for laminated glass provided with the above-described sound insulation and heat insulation, it is difficult to dissolve polyvinyl acetals having different average residual hydroxyl groups constituting each layer. Therefore, the obtained interlayer film for laminated glass has a problem inferior in transparency. In addition, when the intermediate film is recycled, it is difficult to redisperse the heat ray shielding particles in the center layer. This also contributed to the deterioration of transparency.

  From the viewpoint of recent energy saving and effective use of resources, improving the yield of the entire film manufacturing process is a very important issue. Therefore, recycling of an interlayer film for multilayer laminated glass containing heat ray shielding particles, which has been difficult until now, is also demanded, and a solution to the above-described problems is desired.

JP 2011-219670 A JP 2011-219671 A Japanese Patent Laid-Open No. 5-140211 JP-A-5-155915 JP 2002-069126 A JP 2003-252657 A WO2008-122608 JP 2004-143008 A WO2012-077689

  The present invention has been made in order to solve the above-mentioned problems, has sufficient heat ray shielding and sound insulation properties, has little coloration due to heating, has less foreign matter (undissolved content), and is recyclable. Another object of the present invention is to provide an excellent multilayer film. Moreover, it aims at providing the laminated glass which used the said multilayer film as an intermediate film. Furthermore, it aims at providing the manufacturing method of the film using the recovered material of the said multilayer film.

The above-described problem is related to a polyvinyl acetal (I) having a degree of acetalization of 55 to 80 mol% and a vinyl ester monomer unit content of 0.1 to 1.5 mol%, an ultraviolet absorber, and a plasticizer. A layer (X) containing, polyvinyl acetal (II) having a degree of acetalization of 70 to 85 mol% and a vinylester monomer unit content of 5 to 15 mol%, heat ray shielding fine particles, surfactant, A layer (Y) containing an alkali metal salt and / or an alkaline earth metal salt and a plasticizer, and the layers (X) are arranged on both outer sides of the layer (Y), and the polyvinyl acetal (I) and the polyvinyl acetal Acetal (II) is solved by providing a multilayer film satisfying the following formulas (1) and (2).
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)

Where
A: Measured with a differential refractive index detector when polyvinyl acetal (I) or polyvinyl acetal (II) heated at 230 ° C. for 3 hours is measured by gel permeation chromatography (hereinafter sometimes abbreviated as GPC). Peak top molecular weight B: Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when GPC measurement is performed on polyvinyl acetal (I) or polyvinyl acetal (II) heated at 230 ° C. for 3 hours. : Absorbance at peak top molecular weight (B).

However, in the GPC measurement,
Mobile phase: 20 mmol / l sodium trifluoroacetate-containing hexafluoroisopropanol (hereinafter, hexafluoroisopropanol may be abbreviated as HFIP.)
Sample concentration: 1.00 mg / ml
Sample injection volume: 100 μl
Column: “GPC HFIP-806M” manufactured by Showa Denko KK
Column temperature: 40 ° C
Flow rate: 1.0 ml / min Absorbance detector cell length: 10 mm
It is.

At this time, it is preferable that both polyvinyl acetal (I) and polyvinyl acetal (II) satisfy the following formulas (3) and (4).
(AC) / A <0.65 (3)
0.35 × 10 ⁻³ ≦ c ≦ 4.50 × 10 ⁻³ (4)

Where
A: Same as the above formula (1) C: Measured with a spectrophotometric detector (measurement wavelength: 320 nm) when GPC measurement is performed on polyvinyl acetal (I) or polyvinyl acetal (II) heated at 230 ° C. for 3 hours. Peak top molecular weight c: Absorbance at peak top molecular weight (C).

  The polyvinyl acetal (I) and the polyvinyl acetal (II) are preferably polyvinyl butyral (hereinafter sometimes abbreviated as PVB).

  An interlayer film for laminated glass comprising the multilayer film is a preferred embodiment of the present invention. A laminated glass formed by bonding a plurality of glass plates using the interlayer film for laminated glass is also a preferred embodiment of the present invention.

A method for producing a single layer film in which the recovered product of the multilayer film is melt-kneaded and then formed is also a preferred embodiment of the present invention. At this time, the recovered product has a degree of acetalization of 55 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 15 mol%, and the following formulas (1) and (2): It is more preferable to form a film after melt-kneading the polyvinyl acetal (III) to be filled and the plasticizer.
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)
Where
A: Peak top molecular weight measured by a differential refractive index detector when polyvinyl acetal (III) heated at 230 ° C. for 3 hours was measured by gel permeation chromatography B: Polyvinyl acetal heated at 230 ° C. for 3 hours Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when (III) is subjected to gel permeation chromatography measurement: absorbance at peak top molecular weight (B).

However, in the GPC measurement,
Mobile phase: HFIP containing 20 mmol / l sodium trifluoroacetate
Sample concentration: 1.00 mg / ml
Sample injection volume: 100 μl
Column: “GPC HFIP-806M” manufactured by Showa Denko KK
Column temperature: 40 ° C
Flow rate: 1.0 ml / min Absorbance detector cell length: 10 mm
It is.

Collected matter of the multilayer film, the degree of acetalization is 55 to 85 mol%, the content of vinyl ester monomer units is 0.1 to 15 mol%, and the following formulas (1) and (2) Both outer sides of the layer (Y ′) formed by melt-kneading the polyvinyl acetal (III), plasticizer, heat ray shielding fine particles, surfactant, and alkali metal salt and / or alkaline earth metal salt satisfying In addition, a method for producing a multilayer film in which a layer (X) formed by melt-kneading polyvinyl acetal (I), an ultraviolet absorber and a plasticizer and then forming a film is also a preferred embodiment of the present invention.
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)

Where
A: Peak top molecular weight B measured with a differential refractive index detector when GPC measurement is performed on polyvinyl acetal (III) heated at 230 ° C. for 3 hours: Polyvinyl acetal (III) heated at 230 ° C. for 3 hours Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when GPC measurement is performed: Absorbance at peak top molecular weight (B).

However, in the GPC measurement,
Mobile phase: HFIP containing 20 mmol / l sodium trifluoroacetate
Sample concentration: 1.00 mg / ml
Sample injection volume: 100 μl
Column: “GPC HFIP-806M” manufactured by Showa Denko KK
Column temperature: 40 ° C
Flow rate: 1.0 ml / min Absorbance detector cell length: 10 mm
It is.

  The multilayer film of the present invention has sufficient heat ray shielding properties and sound absorption properties, is less colored by heating, has less foreign matter (undissolved content), and is excellent in recyclability. Therefore, the multilayer film is useful as an interlayer film for laminated glass. Furthermore, the film obtained by the manufacturing method using the recovered material of the multilayer film has excellent transparency since it is less colored and has less foreign matter (undissolved content).

In the polyvinyl acetal (I) of Example 1, the relationship between the molecular weight and the value measured by the differential refractive index detector (RI), and the absorbance measured by the molecular weight and the spectrophotometric detector (UV) (measurement wavelength 280 nm). It is the graph which showed the relationship.

The multilayer film of the present invention is a polyvinyl acetal (I) having a degree of acetalization of 55 to 80 mol% and a vinyl ester monomer unit content of 0.1 to 1.5 mol%, an ultraviolet absorber, And a layer (X) containing a plasticizer,
Polyvinyl acetal (II) having a degree of acetalization of 70 to 85 mol% and a vinyl ester monomer unit content of 5 to 15 mol%, heat ray shielding fine particles, surfactant, alkali metal salt and / or alkaline earth A metal salt, and a layer (Y) containing a plasticizer,
Layer (X) is disposed on both outer sides of layer (Y),
Polyvinyl acetal (I) and polyvinyl acetal (II) both satisfy the following formulas (1) and (2).
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)

Where
A: Peak top molecular weight measured by a differential refractive index detector when GPC measurement was performed on polyvinyl acetal (I) or polyvinyl acetal (II) heated at 230 ° C. for 3 hours B: heated at 230 ° C. for 3 hours When the polyvinyl acetal (I) or the polyvinyl acetal (II) is measured by GPC, the peak top molecular weight b measured by an absorptiometric detector (measurement wavelength 280 nm) is the absorbance at the peak top molecular weight (B).

However, in the GPC measurement,
Mobile phase: HFIP containing 20 mmol / l sodium trifluoroacetate
Sample concentration: 1.00 mg / ml
Sample injection volume: 100 μl
Column: “GPC HFIP-806M” manufactured by Showa Denko KK
Column temperature: 40 ° C
Flow rate: 1.0 ml / min Absorbance detector cell length: 10 mm
It is.

  In the present invention, the GPC measurement of polyvinyl acetal (I) and the GPC measurement of polyvinyl acetal (II) are performed under the same conditions. In the GPC measurement in the present invention, a GPC apparatus having a differential refractive index detector and an absorptiometric detector and capable of simultaneously performing measurement by these detectors is used. The absorptiometric detector needs to be capable of measuring absorbance at a wavelength of 280 nm, and preferably is capable of simultaneously measuring absorbance at a wavelength of 280 nm and absorbance at a wavelength of 320 nm. A cell having a cell length (optical path length) of 10 mm is used as the cell of the detection unit of the absorptiometer. The absorptiometric detector may measure the absorption of ultraviolet light having a specific wavelength, or may measure the absorption of ultraviolet light having a specific range of wavelengths. The polyvinyl acetal subjected to the measurement is separated into each molecular weight component by a GPC column. The signal intensity by the differential refractive index detector is approximately proportional to the polyvinyl acetal concentration (mg / ml). On the other hand, polyvinyl acetal detected by an absorptiometric detector is only one having absorption at a predetermined wavelength. By the GPC measurement, it is possible to measure the concentration and absorbance at a predetermined wavelength for each molecular weight component of polyvinyl acetal.

  HFIP containing sodium trifluoroacetate at a concentration of 20 mmol / l is used as the solvent and mobile phase used for dissolving the polyvinyl acetal measured in the GPC measurement. HFIP can dissolve polyvinyl acetal and polymethyl methacrylate (hereinafter abbreviated as PMMA). Further, by adding sodium trifluoroacetate, adsorption of polyvinyl acetal to the column filler is prevented. The flow rate in the GPC measurement is 1.0 ml / min, and the column temperature is 40 ° C.

  In the GPC measurement, monodisperse PMMA (hereinafter referred to as standard PMMA) is used as a standard. Several types of standard PMMA with different molecular weights are measured, and a calibration curve is created from the GPC elution volume and the molecular weight of the standard PMMA. In the present invention, a calibration curve created using the detector is used for measurement by the differential refractive index detector, and a calibration curve created using the detector is used for measurement by the absorptiometric detector. Using these calibration curves, the molecular weight is converted from the GPC elution volume, and the peak top molecular weight (A) and peak top molecular weight (B) of polyvinyl acetal are determined.

  Prior to the GPC measurement, the polyvinyl acetal is heated at 230 ° C. for 3 hours. In the present invention, polyvinyl acetal is heated by the following method. In order to clearly reflect the difference in hue of the sample after the heat treatment in the difference in absorbance, the polyvinyl acetal (film) heated by pressing the polyvinyl acetal powder at 2 MPa and 230 ° C. for 3 hours. Get. The thickness of the film at this time is 600-800 micrometers, and it is preferable that it is about 760 micrometers which is the thickness of a normal laminated glass intermediate film.

  The heated polyvinyl acetal is dissolved in the above-mentioned solvent to obtain a measurement sample. The concentration of polyvinyl acetal in the measurement sample is 1.00 mg / ml, and the injection volume is 100 μl. However, when the viscosity average polymerization degree of the polyvinyl acetal exceeds 2400, the excluded volume increases, and therefore the polyvinyl acetal concentration may not be measured with good reproducibility at a concentration of 1.00 mg / ml. In that case, an appropriately diluted sample (injection amount 100 μl) is used. Absorbance is proportional to the concentration of polyvinyl acetal. Therefore, the absorbance when the polyvinyl acetal concentration is 1.00 mg / ml is determined using the concentration of the diluted sample and the actually measured absorbance.

  FIG. 1 shows the relationship between the molecular weight obtained by GPC measurement of polyvinyl acetal (I) and the value measured by a differential refractive index detector, and the molecular weight and absorptiometric detector in the examples of the present invention described later. It is the graph which showed the relationship with the light absorbency measured by (measurement wavelength 280nm). The GPC measurement in the present invention will be further described with reference to FIG. In FIG. 1, the chromatogram indicated by “RI” is a plot of the value measured by the differential refractive index detector against the molecular weight (horizontal axis) of polyvinyl acetal (I) converted from the elution volume. . In the present invention, the molecular weight at the peak position in the chromatogram is defined as peak top molecular weight (A). When there are a plurality of peaks in the chromatogram, the molecular weight at the peak position where the peak height is the highest is the peak top molecular weight (A). The peak top molecular weight (A) of polyvinyl acetal (II) is also determined in the same manner as described above.

  In FIG. 1, the chromatogram indicated by “UV” plots the absorbance measured by an absorptiometric detector (measurement wavelength 280 nm) against the molecular weight (horizontal axis) of polyvinyl acetal (I) converted from the elution volume. It is a thing. In the present invention, the molecular weight at the peak position in the chromatogram is defined as peak top molecular weight (B), and the absorbance at peak top molecular weight (B) is defined as absorbance (b). When there are a plurality of peaks in the chromatogram, the molecular weight at the peak position where the peak height is the highest is the peak top molecular weight (B). The peak top molecular weight (B) and absorbance (b) of polyvinyl acetal (II) are also determined in the same manner as described above.

The polyvinyl acetal (I) and the polyvinyl acetal (II) used in the present invention are both a peak top molecular weight (A) measured by a differential refractive index detector and an absorptivity when GPC measurement is performed by the method described above. The peak top molecular weight (B) measured with a detector (measurement wavelength: 280 nm) satisfies the following formula (1).
(AB) / A <0.60 (1)

  The peak top molecular weight (A) is a value serving as an index of the molecular weight of polyvinyl acetal. On the other hand, the peak top molecular weight (B) is derived from a component present in polyvinyl acetal and having absorption at 280 nm. Usually, since the peak top molecular weight (A) is larger than the peak top molecular weight (B), (AB) / A becomes a positive value. If the peak top molecular weight (B) increases, (AB) / A decreases, and if the peak top molecular weight (B) decreases, (AB) / A increases. That is, when (A-B) / A is large, it means that there are many components that absorb ultraviolet rays having a wavelength of 280 nm in the low molecular weight components in the polyvinyl acetal.

In the case where (AB) / A in the polyvinyl acetal (I) and the polyvinyl acetal (II) is 0.60 or more, as described above, the component having a wavelength of 280 nm is absorbed in the low molecular weight component. In this case, the foreign matter (undissolved part) in the obtained multilayer film increases. For this reason, foreign matter (undissolved content) in the film produced by using the recovered material (trim, off-spec product, etc.) of the multilayer film also increases, and the transparency of the film decreases. The polyvinyl acetal (I) and the polyvinyl acetal (II) both preferably satisfy the following formula (1 ′), and more preferably satisfy the following formula (1 ″).
(AB) / A <0.55 (1 ′)
(A−B) / A <0.50 (1 ″)

The polyvinyl acetal (I) and the polyvinyl acetal (II) used in the present invention each have an absorbance (b) (measurement wavelength of 280 nm) at the peak top molecular weight (B) when GPC measurement is performed by the method described above. Satisfy (2).
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)

When the absorbance (b) is less than 0.50 × 10 ⁻³ , foreign matter (undissolved content) in the multilayer film increases. Therefore, the foreign material (undissolved part) in the film manufactured using the collection | recovery of the said multilayer film also increases, and the transparency of the said film falls. On the other hand, when the absorbance (b) exceeds 1.00 × 10 ⁻² , the resulting multilayer film is colored by heating. Moreover, the film manufactured using the recovered material of the multilayer film is colored. The polyvinyl acetal (I) and the polyvinyl acetal (II) both preferably satisfy the following formula (2 ′), and more preferably satisfy the following formula (2 ″).
1.00 × 10 ⁻³ ≦ b ≦ 8.00 × 10 ⁻³ (2 ′)
1.50 × 10 ⁻³ ≦ b ≦ 6.50 × 10 ⁻³ (2 ″)

In the multilayer film of the present invention, the polyvinyl acetal (I) and the polyvinyl acetal (II) are both subjected to GPC measurement by the above-mentioned method from the viewpoint of excellent balance between suppression of coloring and reduction of foreign matters (undissolved content). The peak top molecular weight (A) measured with a differential refractive index detector and the peak top molecular weight (C) measured with an absorptiometric detector (measurement wavelength 320 nm) satisfy the following formula (3). preferable.
(AC) / A <0.65 (3)

  The peak top molecular weight (C) is measured in the same manner as the peak top molecular weight (B) except that the measurement wavelength in the absorptiometric detector is 320 nm. A peak top molecular weight (C) originates in the component which has absorption in 320 nm which exists in polyvinyl acetal. Usually, since the peak top molecular weight (A) is larger than the peak top molecular weight (C), (AC) / A becomes a positive value. If the peak top molecular weight (C) increases, (AC) / A decreases, and if the peak top molecular weight (C) decreases, (AC) / A increases. That is, when (AC) / A is large, it means that there are many components that absorb ultraviolet light having a wavelength of 320 nm among the low molecular weight components in polyvinyl acetal.

When (AC) / A in the polyvinyl acetal (I) and the polyvinyl acetal (II) is 0.65 or more, as described above, the low molecular weight component contains more components that absorb ultraviolet light having a wavelength of 320 nm. In this case, there is a possibility that foreign matter (undissolved content) in the obtained multilayer film increases. When the said foreign material (undissolved part) increases, the foreign material (undissolved part) in the film manufactured using the collection | recovery of a multilayer film may also increase, and there exists a possibility that the transparency of the said film may fall. The polyvinyl acetal (I) and the polyvinyl acetal (II) both preferably satisfy the following formula (3 ′), and more preferably satisfy the following formula (3 ″).
(AC) / A <0.60 (3 ′)
(AC) / A <0.55 (3 ")

The polyvinyl acetal (I) and the polyvinyl acetal (II) both have an absorbance (c) (measurement wavelength of 320 nm) at the peak top molecular weight (C) when GPC measurement is performed by the above-described method satisfies the following formula (4). It is preferable.
0.35 × 10 ⁻³ ≦ c ≦ 4.50 × 10 ⁻³ (4)

When the absorbance (c) is less than 0.35 × 10 ⁻³ , foreign matter (undissolved content) in the multilayer film may increase. When the said foreign material (undissolved part) increases, the foreign material (undissolved part) in the film manufactured using the collection | recovery of a multilayer film may also increase, and there exists a possibility that the transparency of the said film may fall. On the other hand, when the absorbance (c) exceeds 4.50 × 10 ⁻³ , the resulting multilayer film may be easily colored by heating. Moreover, there exists a possibility that the film manufactured using the collection | recovery of the said multilayer film may become easy to color. The polyvinyl acetal (I) and the polyvinyl acetal (II) both preferably satisfy the following formula (4 ′), and more preferably satisfy the following formula (4 ″).
0.50 × 10 ⁻³ ≦ c ≦ 3.50 × 10 ⁻³ (4 ′)
1.00 × 10 ⁻³ ≦ c ≦ 2.50 × 10 ⁻³ (4 ″)

  Further, the polyvinyl acetal (I) and the polyvinyl acetal (II) both have a ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of 2.8 to 2.8, as determined by the differential refractive index detector in the GPC measurement. It is preferably 12.0. Mw and Mn are obtained from a chromatogram obtained by plotting the values measured by the differential refractive index detector with respect to the molecular weight of polyvinyl acetal. Mw and Mn in the present invention are values in terms of PMMA.

  In general, Mn is an average molecular weight that is strongly influenced by a low molecular weight component, and Mw is an average molecular weight that is strongly influenced by a high molecular weight component. Mw / Mn is generally used as an index of molecular weight distribution of a polymer. When Mw / Mn is small, it indicates that the polymer has a small proportion of low molecular weight component, and when Mw / Mn is large, it indicates that the polymer has a large proportion of low molecular weight component.

  Therefore, in this invention, when Mw / Mn is less than 2.8, it shows that the ratio of a low molecular weight component is small in polyvinyl acetal (I) and polyvinyl acetal (II). When Mw / Mn is less than 2.8, foreign matter (undissolved content) in the resulting multilayer film may increase. When the said foreign material (undissolved part) increases, the foreign material (undissolved part) in the film manufactured using the collection | recovery of a multilayer film may also increase, and there exists a possibility that the transparency of the said film may fall. Mw / Mn is more preferably 2.9 or more, and further preferably 3.1 or more. On the other hand, when Mw / Mn exceeds 12.0, it shows that the ratio of a low molecular weight component is large in polyvinyl acetal. When Mw / Mn exceeds 12.0, the resulting multilayer film may be easily colored by heating. Moreover, there exists a possibility that the film manufactured using the collection | recovery of the said multilayer film may become easy to color. Mw / Mn is more preferably 11.0 or less, and even more preferably 8.0 or less.

In the present invention, the viscosity average degree of polymerization of polyvinyl acetal (I) and polyvinyl acetal (II) is represented by the viscosity average degree of polymerization of the raw material PVA measured according to JIS-K6726. That is, after re-saponifying and purifying PVA to a saponification degree of 99.5 mol% or more, it can be obtained from the intrinsic viscosity [η] measured in water at 30 ° C. by the following equation. The viscosity average polymerization degree of PVA and the viscosity average polymerization degree of polyvinyl acetal obtained by acetalizing it are substantially the same.
P = ([η] × 10000 / 8.29) ^{(1 / 0.62)}

  It is preferable that the viscosity average polymerization degree of the polyvinyl acetal (I) and the polyvinyl acetal (II) used in the present invention is 200 to 5,000. When the viscosity average polymerization degree is less than 200, the practical strength of polyvinyl acetal cannot be obtained, and the strength of the multilayer film may be insufficient. Moreover, it may be difficult to industrially produce PVA used for producing such polyvinyl acetal. The viscosity average degree of polymerization is more preferably 250 or more, further preferably 300 or more, and particularly preferably 400 or more. On the other hand, when the viscosity average degree of polymerization exceeds 5000, the melt viscosity may become too high and film formation may be difficult. The viscosity average degree of polymerization is more preferably 4500 or less, further preferably 4000 or less, and particularly preferably 3500 or less.

  When the multilayer film of the present invention is used as a laminated glass interlayer, the viscosity average polymerization degree of polyvinyl acetal (I) and polyvinyl acetal (II) is preferably 500 to 5000, more preferably 800 to 3500, and 1000 ˜2500 is more preferred. When the degree of polymerization is less than 500, there is a possibility that sufficient strength as an interlayer film for laminated glass cannot be obtained. On the other hand, when the viscosity average degree of polymerization exceeds 5000, the melt viscosity becomes too high and film formation may be difficult.

  The degree of acetalization of the polyvinyl acetal (I) used in the present invention is 55 to 80 mol%. When the degree of acetalization is less than 55 mol%, the compatibility with a plasticizer or the like decreases. Moreover, the foreign material (undissolved part) in a multilayer film increases. Moreover, the foreign material (undissolved part) in the film manufactured using the collection | recovery of the said multilayer film also increases, and the transparency of the said film falls. The degree of acetalization of the polyvinyl acetal (I) is preferably 60 mol% or more, more preferably 65 mol% or more. On the other hand, when the degree of acetalization exceeds 80 mol%, it may be easy to color. The degree of acetalization of the polyvinyl acetal (I) is preferably 75 mol% or less.

  The degree of acetalization of the polyvinyl acetal (II) used in the present invention is 70 to 85 mol%. When the degree of acetalization exceeds 85 mol%, the efficiency of the acetalization reaction is significantly reduced. In addition, the multilayer film is colored by heating. Furthermore, the film manufactured using the recovered material of the multilayer film is also colored. The degree of acetalization of polyvinyl acetal (II) is preferably 80 mol% or less. On the other hand, when the degree of acetalization is less than 70 mol%, foreign matter (undissolved content) in the film may increase.

  The difference between the degree of acetalization of polyvinyl acetal (I) and the degree of acetalization of polyvinyl acetal (II) from the point of excellent balance between the coloring resistance of the resulting multilayer film and the amount of foreign matter (undissolved) (II− I) is preferably 2 mol% or more, and more preferably 4 mol% or more.

  In the present invention, the degree of acetalization represents the ratio of acetalized vinyl alcohol monomer units to all monomer units constituting polyvinyl acetal. Among the vinyl alcohol monomer units in the raw material PVA, those that are not acetalized remain in the resulting polyvinyl acetal as vinyl alcohol monomer units.

  Content of the vinyl ester monomer unit of polyvinyl acetal (I) used in the present invention is 0.1 to 1.5 mol%. When the content of the vinyl ester monomer unit is less than 0.1 mol%, the polyvinyl acetal cannot be stably produced and the film cannot be formed. The content of the vinyl ester monomer unit is preferably 0.3 mol% or more, more preferably 0.5 mol% or more, and further preferably 0.7 mol% or more. On the other hand, the content of the vinyl ester monomer unit is preferably 1.2 mol% or less.

  The content of the vinyl ester monomer unit of polyvinyl acetal (II) used in the present invention is 5 to 15 mol%. When the content of the vinyl ester monomer unit exceeds 15 mol%, the resulting multilayer film is colored by heating. Furthermore, the film manufactured using the recovered material of the multilayer film is also colored. The content of the vinyl ester monomer unit of polyvinyl acetal (II) is preferably 13 mol% or less, more preferably 10 mol% or less. On the other hand, the content of the vinyl ester monomer unit is preferably 6 mol% or more, more preferably 7 mol% or more. When the content of the vinyl ester monomer unit of polyvinyl acetal (II) is in the above range, the layer (Y) becomes a soft layer, and the multilayer film of the present invention maintains a practical mechanical strength. , Has excellent sound insulation performance.

  The content of the vinyl alcohol monomer unit of the polyvinyl acetal (I) used in the present invention is preferably 18.5 to 44.9 mol%. The content of the vinyl alcohol monomer unit of the polyvinyl acetal (II) used in the present invention is preferably 5 to 25 mol%.

  Moreover, in this invention, content (mol%) of the vinyl alcohol monomer unit of polyvinyl acetal (I) is larger than content (mol%) of the vinyl alcohol monomer unit of polyvinyl acetal (II). It is preferable. The result that the affinity of the surfactant for the layer (Y) is higher than the affinity for the layer (X) by providing a difference in the content of the vinyl alcohol monomer units in the layer (X) and the layer (Y) The bleed-out of the surfactant can be effectively suppressed. The difference (I-II) between the content of the vinyl alcohol monomer unit of polyvinyl acetal (I) and the content of the vinyl alcohol monomer unit of polyvinyl acetal (II) is preferably 5 mol% or more, More preferably, it is 10 mol% or more. On the other hand, the difference (I-II) is preferably 30 mol% or less.

  Content of monomer units other than acetalized monomer unit, vinyl ester monomer unit and vinyl alcohol monomer unit in polyvinyl acetal (I) and polyvinyl acetal (II) used in the present invention Is preferably 20 mol% or less, more preferably 10 mol% or less, and even more preferably 5 mol% or less.

  The polyvinyl acetal (I) and the polyvinyl acetal (II) used in the present invention are usually produced by acetalizing PVA.

  The saponification degree of the raw material PVA used for the production of the polyvinyl acetal (I) and the polyvinyl acetal (II) is preferably 80 to 99.9 mol%, more preferably 82 to 99.7 mol%, still more preferably 85 to 85 mol%. 99.5 mol%, most preferably 87-99.3 mol%. When the degree of saponification is less than 80 mol%, there is a risk that foreign matter (undissolved content) in the resulting multilayer film may increase, or the resulting multilayer film may be easily colored by heating. On the other hand, when the degree of saponification exceeds 99.9 mol%, PVA may not be produced stably. The degree of saponification of PVA is measured according to JIS-K6726.

  Examples of vinyl ester monomers used for the production of raw material PVA include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and versa. Examples thereof include vinyl tick acid, and vinyl acetate is particularly preferable.

  The raw material PVA can also be produced by polymerizing a vinyl ester monomer in the presence of a thiol compound such as 2-mercaptoethanol, n-dodecyl mercaptan, mercaptoacetic acid, 3-mercaptopropionic acid, and saponifying the resulting polyvinyl ester. You can also By this method, PVA in which a functional group derived from a thiol compound is introduced at the terminal is obtained.

  Examples of the method for polymerizing the vinyl ester monomer include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among the methods, a bulk polymerization method performed without a solvent or a solution polymerization method performed using a solvent such as alcohol is usually employed. In terms of enhancing the effect of the present invention, a solution polymerization method in which polymerization is performed together with a lower alcohol is preferable. The lower alcohol is not particularly limited, but an alcohol having 3 or less carbon atoms such as methanol, ethanol, propanol and isopropanol is preferable, and methanol is usually used. When performing the polymerization reaction by the bulk polymerization method or the solution polymerization method, the reaction can be carried out by either a batch method or a continuous method. Examples of the initiator used for the polymerization reaction include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl-valeronitrile), 2,2′-azobis (4-methoxy). -2,4-dimethylvaleronitrile) and other azo-based initiators; organic peroxide-based initiators such as benzoyl peroxide, n-propyl peroxycarbonate, peroxydicarbonate and the like, as long as the effects of the present invention are not impaired. Known initiators may be mentioned. Particularly preferred are organic oxide-based initiators having a half-life of 10 to 110 minutes at 60 ° C. Among them, it is preferable to use peroxydicarbonate. Although there is no restriction | limiting in particular about the polymerization temperature at the time of performing a polymerization reaction, The range of 5 to 200 degreeC is suitable.

  When the vinyl ester monomer is radically polymerized, a copolymerizable monomer can be copolymerized as necessary as long as the effects of the present invention are not impaired. Examples of such monomers include α-olefins such as ethylene, propylene, 1-butene, isobutene, and 1-hexene; carboxylic acids such as fumaric acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride; Derivatives thereof; acrylic acid or salts thereof; acrylic esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate; methacrylic acid or salts thereof; methyl methacrylate, ethyl methacrylate, n methacrylate Methacrylic acid esters such as propyl and isopropyl methacrylate; Acrylamide derivatives such as acrylamide, N-methylacrylamide and N-ethylacrylamide; and methacrylamides such as methacrylamide, N-methylmethacrylamide and N-ethylmethacrylamide Body; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether; hydroxy group-containing vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, 1,4-butanediol vinyl ether Allyl ethers such as allyl acetate, propyl allyl ether, butyl allyl ether, hexyl allyl ether; monomers having an oxyalkylene group; isopropenyl acetate, 3-buten-1-ol, 4-penten-1-ol Hydroxy group-containing α-olefins such as 5-hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol, 3-methyl-3-buten-1-ol; Monomers having sulfonic acid groups such as sulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid; vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyl Cationic groups such as dimethylamine, vinyloxymethyldiethylamine, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine Monomers having vinyl; vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethyl Monomers having silyl groups such as toxisilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, 3- (meth) acrylamide-propyltrimethoxysilane, 3- (meth) acrylamide-propyltriethoxysilane Etc. The amount of these monomers that can be copolymerized with vinyl ester monomers varies depending on the purpose and application of use, but is usually based on all monomers used for copolymerization. The ratio is 20 mol% or less, preferably 10 mol% or less.

  PVA can be obtained by saponifying the polyvinyl ester obtained by the above-mentioned method in an alcohol solvent.

  As the catalyst for the saponification reaction of the polyvinyl ester, an alkaline substance is usually used. Examples thereof include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, and alkali metal alkoxides such as sodium methoxide. The amount of the alkaline substance used is preferably in the range of 0.002 to 0.2 in the molar ratio based on the vinyl ester monomer unit of the polyvinyl ester, and in the range of 0.004 to 0.1. It is particularly preferred that The saponification catalyst may be added all at once in the early stage of the saponification reaction, or a part thereof may be added in the early stage of the saponification reaction, and the rest may be added and added during the saponification reaction.

  Examples of the solvent that can be used for the saponification reaction include methanol, methyl acetate, dimethyl sulfoxide, diethyl sulfoxide, dimethylformamide, and the like. Of these solvents, methanol is preferably used. At this time, the moisture content of methanol is preferably adjusted to 0.001 to 1% by mass, more preferably 0.003 to 0.9% by mass, and particularly preferably 0.005 to 0.8% by mass.

  The saponification reaction is preferably performed at a temperature of 5 to 80 ° C, more preferably 20 to 70 ° C. The saponification reaction is preferably performed for 5 minutes to 10 hours, more preferably for 10 minutes to 5 hours. The saponification reaction can be performed by either a batch method or a continuous method. After completion of the saponification reaction, the remaining catalyst may be neutralized as necessary. Usable neutralizing agents include organic acids such as acetic acid and lactic acid, and ester compounds such as methyl acetate.

  The alkaline substance containing an alkali metal added during the saponification reaction is usually neutralized by an ester such as methyl acetate generated by the progress of the saponification reaction, or neutralized by a carboxylic acid such as acetic acid added after the reaction. At this time, an alkali metal salt of a carboxylic acid such as sodium acetate is formed. As will be described later, in the present invention, the raw material PVA preferably contains an alkali metal salt of carboxylic acid in an amount of 0.5% by mass or less in terms of the mass of the alkali metal. In order to obtain such PVA, the PVA may be washed after saponification.

  Examples of the cleaning liquid used in this case include a lower alcohol such as methanol, a solution composed of 100 parts by weight of the lower alcohol and 20 parts by weight or less of water, and a solution composed of the lower alcohol and an ester such as methyl acetate produced in the saponification step. It is done. The content of the ester in the solution composed of the lower alcohol and the ester is not particularly limited, but is preferably 1000 parts by mass or less with respect to 100 parts by mass of the lower alcohol. The addition amount of the cleaning liquid is preferably 100 parts by mass to 10000 parts by mass, more preferably 150 parts by mass to 5000 parts by mass with respect to 100 parts by mass of the gel obtained by saponification and swollen with PVA by alcohol. Part by mass to 1000 parts by mass are more preferable. When the addition amount of the cleaning liquid is less than 100 parts by mass, the alkali metal salt amount of the carboxylic acid may exceed the above range. On the other hand, when the addition amount of the cleaning liquid exceeds 10,000 parts by mass, the improvement of the cleaning effect by increasing the addition amount cannot be expected. Although there is no particular limitation on the method of washing, for example, a step of adding a gel (PVA) and a washing liquid in a tank and stirring or standing at 5 to 100 ° C. for about 5 to 180 minutes and then removing the liquid is performed. A batch method that repeats until the content of the alkali metal salt is within a predetermined range may be mentioned. Further, there is a continuous method in which PVA is continuously added from the top of the column at the same temperature and for the same time as the batch method, and a lower alcohol is continuously added from the bottom of the column, and the two are brought into contact with each other.

  The raw material PVA preferably contains an alkali metal salt of carboxylic acid. The content is preferably 0.50% by mass or less, more preferably 0.37% by mass or less, still more preferably 0.28% by mass or less, and particularly preferably 0.23% by mass or less in terms of alkali metal mass. is there. When content of the alkali metal salt of carboxylic acid exceeds 0.5 mass%, the obtained polyvinyl acetal or a film produced using the same may be easily colored. The content of alkali metal salt of carboxylic acid (calculated in terms of alkali metal mass) is obtained from the amount of alkali metal ions obtained by ashing PVA with a platinum crucible and then measuring the resulting ash content by ICP emission analysis. Can do.

  Examples of the alkali metal salt of carboxylic acid include those obtained by neutralizing an alkali catalyst used in the above-described saponification step, for example, sodium hydroxide, potassium hydroxide, sodium methylate with carboxylic acid, and a vinyl ester described later. Carboxylic acid added for the purpose of suppressing alcoholysis of the vinyl ester monomer such as vinyl acetate used in the polymerization step is neutralized in the saponification step, added to stop radical polymerization When a carboxylic acid having a conjugated double bond is used as an inhibitor, those obtained by neutralizing the carboxylic acid in the saponification step or those intentionally added are included. Specific examples include sodium acetate, potassium acetate, sodium propionate, potassium propionate, sodium glycerate, potassium glycerate, sodium malate, potassium malate, sodium citrate, potassium citrate, sodium lactate, potassium lactate, tartaric acid Sodium, potassium tartrate, sodium salicylate, potassium salicylate, sodium malonate, potassium malonate, sodium succinate, potassium succinate, sodium maleate, potassium maleate, sodium phthalate, potassium phthalate, sodium oxalate, potassium oxalate , Sodium glutarate, potassium glutarate, sodium abietic acid, potassium abietic acid, sodium sorbate, potassium sorbate, 2,4,6-octatri Sodium -1-carboxylate, potassium 2,4,6-octatriene-1-carboxylate, sodium eleostearate, potassium eleostearate, sodium 2,4,6,8-decatetraene-1-carboxylate 2,4,6,8-decatetraene-1-carboxylate, sodium retinoate, potassium retinoate and the like, but are not limited thereto.

  In the present invention, as a method for adjusting each value obtained by GPC measurement so as to fall within the above-described range, for example, PVA produced by using the following method can be used for polyvinyl acetal (I) and polyvinyl acetal (II). The method used as a raw material is mentioned.

  A) A vinyl ester monomer from which a radical polymerization inhibitor contained in the raw vinyl ester monomer has been removed in advance is used for the polymerization.

  B) A vinyl ester monomer having a total content of impurities contained in the raw material vinyl ester monomer of preferably 1 to 1200 ppm, more preferably 3 to 1100 ppm, and still more preferably 5 to 1000 ppm is used for radical polymerization. Impurities include aldehydes such as acetaldehyde, crotonaldehyde, and acrolein; acetals such as acetaldehyde dimethyl acetal, crotonaldehyde dimethyl acetal, and acrolein dimethyl acetal obtained by acetalizing the aldehyde with a solvent alcohol; ketones such as acetone; methyl acetate and ethyl acetate And esters.

  C) In order to suppress the alcoholysis and hydrolysis of the monomer by alcohol and a small amount of water in a series of steps of radical polymerization of the raw material vinyl ester monomer in an alcohol solvent and collecting and reusing unreacted monomer, Organic acids, specifically hydroxycarboxylic acids such as glycolic acid, glyceric acid, malic acid, citric acid, lactic acid, tartaric acid, salicylic acid; malonic acid, succinic acid, maleic acid, phthalic acid, oxalic acid, glutaric acid, etc. A carboxylic acid or the like is added to suppress the generation of aldehydes such as acetaldehyde generated by decomposition as much as possible. The addition amount of the organic acid is preferably 1 to 500 ppm, more preferably 3 to 300 ppm, and still more preferably 5 to 100 ppm with respect to the raw material vinyl ester monomer.

  D) As a solvent used for polymerization, a solvent having a total content of impurities of preferably 1 to 1200 ppm, more preferably 3 to 1100 ppm, and still more preferably 5 to 1000 ppm. Examples of the impurities contained in the solvent include those described above as the impurities contained in the raw material vinyl ester monomer.

  E) When the vinyl ester monomer is radically polymerized, the ratio of the solvent to the vinyl ester monomer is increased.

  F) An organic peroxide is used as a radical polymerization initiator used for radical polymerization of a vinyl ester monomer. Organic peroxides include acetyl peroxide, isobutyl peroxide, diisopropyl peroxycarbonate, diallyl peroxydicarbonate, di-n-propyl peroxydicarbonate, dimyristyl peroxydicarbonate, and di (2-ethoxyethyl) peroxide. Examples include oxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di (methoxyisopropyl) peroxydicarbonate, and di (4-tert-butylcyclohexyl) peroxydicarbonate. It is preferable to use peroxydicarbonate with a period of 10 to 110 minutes.

  G) When an inhibitor is added after radical polymerization of the vinyl ester monomer to suppress polymerization, an inhibitor of 5 molar equivalents or less is added to the remaining undecomposed radical polymerization initiator. Examples of the inhibitor include a compound having a conjugated double bond having a molecular weight of 1000 or less and a compound that stabilizes a radical and inhibits a polymerization reaction. Specifically, isoprene, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-t-butyl-1,3-butadiene, 1,3-pentadiene, 2 , 3-dimethyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-pentadiene, 3-ethyl-1,3-pentadiene, 2-methyl-1 , 3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 2,5-dimethyl-2,4-hexadiene, , 3-octadiene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1-methoxy-1,3-butadiene, 2-methoxy-1,3-butadiene, 1-ethoxy-1,3- Tadiene, 2-ethoxy-1,3-butadiene, 2-nitro-1,3-butadiene, chloroprene, 1-chloro-1,3-butadiene, 1-bromo-1,3-butadiene, 2-bromo-1, Conjugated dienes composed of a conjugated structure of two carbon-carbon double bonds such as 3-butadiene, fulvene, tropone, osymene, ferrandrene, myrcene, farnesene, semblene, sorbic acid, sorbic acid ester, sorbic acid salt, and abietic acid; 1,3,5-hexatriene, 2,4,6-octatriene-1-carboxylic acid, eleostearic acid, tung oil, conjugated triene having a conjugated structure of three carbon-carbon double bonds such as cholecalciferol Carbons such as cyclooctatetraene, 2,4,6,8-decatetraene-1-carboxylic acid, retinol, retinoic acid, etc. Polyenes such as conjugated polyene consisting Motoni double bond of four or more conjugated structure. Any one having a plurality of stereoisomers such as 1,3-pentadiene, myrcene, and farnesene may be used. Furthermore, p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, 2-phenyl-1-propene, 2-phenyl-1-butene, 2,4-diphenyl-4-methyl-1-pentene, 3,5-diphenyl-5 Methyl-2-heptene, 2,4,6-triphenyl-4,6-dimethyl-1-heptene, 3,5,7-triphenyl-5-ethyl-7-methyl-2-nonene, 1,3- Diphenyl-1-butene, 2,4-diphenyl-4-methyl-2-pentene, 3,5-diphenyl-5-methyl-3-heptene, 1,3,5-triphenyl-1-hexene, 2,4 , 6-triphenyl-4,6-dimethyl-2-heptene, 3,5,7-triphenyl-5-ethyl-7-methyl-3-nonene, 1-phenyl-1,3-butadiene, 1,4 - Aromatic compounds such as Eniru 1,3-butadiene.

  H) An alcohol solution of polyvinyl ester from which the remaining vinyl ester monomer is removed as much as possible is used for the saponification reaction. Preferably, the residual monomer removal rate is 99% or more, more preferably 99.5% or more, still more preferably 99.8% or more.

  It is preferable to acetalize PVA produced by appropriately combining A) to H) to obtain polyvinyl acetal (I) and polyvinyl acetal (II).

  Acetalization of PVA used as a raw material for polyvinyl acetal (I) and polyvinyl acetal (II) can be carried out, for example, under the following reaction conditions, but is not limited thereto. After heating to 80-100 degreeC and dissolving PVA in water, the 3-40 mass% aqueous solution of PVA is obtained by cooling slowly over 10-60 minutes. When the temperature falls to −10 to 30 ° C., an aldehyde and an acid catalyst are added to the aqueous solution, and an acetalization reaction is performed for 30 to 300 minutes while keeping the temperature constant. At that time, polyvinyl acetal having reached a certain degree of acetalization is precipitated. Thereafter, the temperature of the reaction solution is raised to 25 to 80 ° C. over 30 to 300 minutes, and the temperature is maintained for 10 minutes to 24 hours (this temperature is set as the reaction temperature for driving in). Next, a neutralizing agent such as an alkali is added to the reaction solution as necessary to neutralize the acid catalyst, and the resultant is washed with water and dried to obtain polyvinyl acetal.

  In general, aggregated particles made of polyvinyl acetal are generated in such a reaction or processing step, and coarse particles are easily formed. When such coarse particles are generated, there is a risk of causing variation between batches. On the other hand, when the PVA produced using the above-described A) to H) is used as a raw material, the generation of coarse particles is suppressed from the conventional product, and as a result, when the resulting polyvinyl acetal is melt-formed, foreign matter is produced. A multilayer film with a further reduced (undissolved content) can be obtained.

  It does not specifically limit as an acid catalyst used for acetalization reaction, Either an organic acid and an inorganic acid can be used. For example, acetic acid, p-toluenesulfonic acid, nitric acid, sulfuric acid, hydrochloric acid and the like can be mentioned. Of these, hydrochloric acid, sulfuric acid, and nitric acid are preferably used. In general, when nitric acid is used, the reaction rate of the acetalization reaction is increased, and improvement in productivity can be expected. On the other hand, the obtained polyvinyl acetal particles tend to be coarse and the variation between batches tends to increase. is there. On the other hand, when PVA produced using the above-described predetermined method is used as a raw material, the formation of coarse particles is suppressed, and as a result, when the resulting polyvinyl acetal is melt-formed, foreign matter (undissolved content) Can be obtained.

  In the present invention, the aldehyde used in the acetalization reaction is not particularly limited, but a known aldehyde having 1 to 8 carbon atoms is preferable, an aldehyde having 4 to 6 carbon atoms is more preferable, and n-butyraldehyde is particularly preferably used. In the present invention, polyvinyl acetal obtained by using two or more aldehydes in combination can also be used.

  The plasticizer contained in the layer (X) and the layer (Y) is not particularly limited as long as the effect of the present invention is not impaired and there is no problem in compatibility with polyvinyl acetal. The plasticizers can be used alone or in combination of two or more. The plasticizer is preferably a diester of an oligoalkylene glycol having a hydroxyl group at both ends and an aliphatic carboxylic acid, or a diester of an alkylene dicarboxylic acid and an aliphatic monohydric alcohol. Examples of the oligoalkylene glycol having hydroxyl groups at both ends include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,2-propylene glycol dimer and trimer, 1,3 -Propylene glycol, 1,3-propylene glycol dimer and trimer, 1,2-butylene glycol, 1,2-butylene glycol dimer and trimer, 1,4-butylene glycol, 1, 4-butylene glycol dimer and trimer, 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,2-octanediol, 1,8-octane Diol, 1,9-nonanediol, 2-methyl-1,8-octanediol, , 2-decanediol, 1,4-cyclohexane diol. Examples of the aliphatic carboxylic acid include acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid and decanoic acid. Here, the combination of oligoalkylene glycol and aliphatic carboxylic acid is arbitrary, and may be a combination of a plurality of oligoalkylene glycols and a plurality of carboxylic acids. Among these, a diester of triethylene glycol and 2-ethylhexanoic acid is preferable from the viewpoint of handleability (volatility during molding). Triethylene glycol di-2-ethylhexanoate is particularly preferable. Examples of the alkylene dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and sebacic acid. Examples of the aliphatic monohydric alcohol include methanol, ethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, heptanol, octanol, 2-ethylhexanol, nonaol, decanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxy. Examples include ethanol and 2-butoxyethanol. Here, the combination of an alkylene dicarboxylic acid and an aliphatic monohydric alcohol is arbitrary, and a combination of a plurality of alkylene dicarboxylic acids and a plurality of aliphatic monohydric alcohols may be used.

  As the plasticizer, an aliphatic compound having a hydroxyl group such as an aliphatic ester compound having a hydroxyl group or an aliphatic ether compound having a hydroxyl group may be used. The number of hydroxyl groups in these compounds is preferably 2 or more, more preferably 2 to 3. The aliphatic ester compound having a hydroxyl group is a compound having at least one ester bond and having a hydroxyl group, and the aliphatic ether compound having a hydroxyl group is a compound having at least one ether bond and having a hydroxyl group. .

  The aliphatic ester compound having a hydroxyl group is not particularly limited, but methyl ricinoleate, butyl ricinoleate, 2-ethylhexyl ricinoleate, ricinoleic acid (2-hydroxyethyl), glycerin monoricinoleate, glycerin diricinoleate, glycerin triglyceride. Ricinoleic acid ester, glycerin diricinoleic acid monooleate, oleic acid (2-hydroxyethyl), 2-ethylhexanoic acid (2-hydroxyethyl), ricinoleic acid {2- [2- (2-hydroxyethoxy) ethoxy ] Ethyl} 2-ethylhexanoic acid {2- [2- (2-hydroxyethoxy) ethoxy] ethyl}, methyl ricinoleate, ethyl ricinoleate, butyl ricinoleate, octyl ricinoleate, octyl 6-hydroxyhexanoate Le, 12-hydroxystearic acid methyl other such castor, and polyester compounds having a hydroxyl group. The castor oil is glycerin tricarboxylic acid ester obtained from the seed of castor, and most of the carboxylic acid ester part, usually 80 to 95% by mass is ricinoleic acid ester, and the rest is palmitic acid ester, stearic acid ester, It is composed of oleic acid ester, linoleic acid ester, linolenic acid ester and the like.

  Examples of the polyester compound having a hydroxyl group include an aliphatic polyester having a hydroxyl group, which is a condensation copolymer of a polyvalent carboxylic acid and a polyhydric alcohol, an aliphatic polyester having a hydroxyl group, which is a polymer of a hydroxycarboxylic acid, and a hydroxyl group. Aliphatic polycarbonate polyol having

  An aliphatic polyester having a hydroxyl group, which is a condensation copolymer of a polycarboxylic acid and a polyhydric alcohol, can be obtained by condensation polymerization of an aliphatic polycarboxylic acid and an aliphatic polyhydric alcohol in an excess of polyhydric alcohol. .

  Aliphatic polycarboxylic acids include succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, 1,2-cyclohexanedicarboxylic acid and other aliphatic divalent carboxylic acids, 1,2,3-propane Examples thereof include, but are not limited to, tricarboxylic acids and aliphatic trivalent carboxylic acids such as 1,3,5-pentatricarboxylic acid. Among these, aliphatic divalent carboxylic acids, particularly aliphatic divalent carboxylic acids having 6 to 10 carbon atoms are preferred. Examples of the aliphatic polyhydric alcohol include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,2-hexane. Diol, 3-methyl-1,5-pentanediol, 1,2-octanediol, 1,2-nonanediol, 1,8-nonanediol, 1,9-nonanediol, 1,2-cyclohexanediol, 1, Examples include aliphatic dihydric alcohols such as 2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol and triethylene glycol; aliphatic trihydric alcohols such as glycerin; aliphatic tetrahydric alcohols such as erythritol and pentaerythritol. However, it is not limited to these. Of these, aliphatic dihydric alcohols are preferred from the viewpoint of excellent weather resistance of the resulting polyester.

  An aliphatic polyester having a hydroxyl group, which is a polymer of hydroxycarboxylic acid, can be obtained by condensation polymerization of hydroxycarboxylic acid. Examples of the hydroxycarboxylic acid include glycolic acid, lactic acid, 2-hydroxybutanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6-hydroxyhexanoic acid, and ricinoleic acid. A lactone compound obtained by intramolecular condensation of these hydroxycarboxylic acids can also be used as a raw material. Examples of the lactone compound include, but are not limited to, β-butyrolactone, δ-valerolactone, ε-caprolactone, 4-methyl-δ-valerolactone, and the like. When a lactone compound is used, a polyester can be obtained by ring-opening polymerization. Among these, 6-hydroxycarboxylic acid or ε-caprolactone is preferable from the viewpoint of excellent heat resistance of polyester.

  Examples of the aliphatic ether compound having a hydroxyl group include ethylene glycol monohexyl ether and an aliphatic polyether compound having a hydroxyl group. Among these, an aliphatic polyether compound having a hydroxyl group is preferable. The aliphatic polyether compound having a hydroxyl group is a polymer of an aliphatic polyhydric alcohol such as ethylene glycol or 1,2-propylene glycol and having a hydroxyl group. For example, polyethylene glycol and polypropylene glycol are preferable.

  Although the molecular weight of the aliphatic compound which has a hydroxyl group is not specifically limited, Preferably it is 200-2000, More preferably, it is 220-1000, More preferably, it is 250-700. The number average molecular weight based on the hydroxyl value of the compound is not particularly limited, but is preferably 200 to 2000, more preferably 220 to 1700, and further preferably 240 to 1500. When the number average molecular weight based on the hydroxyl value is smaller than 200, the boiling point of the compound may not be sufficiently high, and high volatility may be a problem. When the number average molecular weight based on the hydroxyl value is larger than 2000, the compatibility between the compound and polyvinyl acetal may be insufficient. The number average molecular weight based on the hydroxyl value is (number of hydroxyl groups per molecule having a hydroxyl group) / (substance amount of hydroxyl group per 1 g of the compound having a hydroxyl group [mol / g]) = 1000 × (compound having a hydroxyl group) This is a value obtained by (number of hydroxyl groups per molecule) / ((hydroxyl value of a compound having a hydroxyl group) / 56). Here, when two or more types of aliphatic compounds having a hydroxyl group are used as a mixture, the number of hydroxyl groups per molecule of a compound having a hydroxyl group indicates an average value per molecule of the compound having a hydroxyl group contained in the mixture. .

  The hydroxyl value of the aliphatic compound having a hydroxyl group is not particularly limited, but is preferably 50 to 600 mgKOH / g, more preferably 70 to 500 mgKOH / g, and still more preferably 100 to 400 mgKOH / g. If the hydroxyl value is less than 50 mgKOH / g, the transparency of the resulting multilayer film may be reduced. On the other hand, when the hydroxyl value exceeds 600 mgKOH / g, the compatibility with polyvinyl acetal is lowered, transparency may be lowered, and bleeding may occur from the multilayer film. Here, the hydroxyl value in the present invention is a value obtained by measurement by the method described in JIS K1557-1 (2007). The hydroxyl value in the case of using a mixture of two or more compounds having a hydroxyl group is a mixture thereof (mixture of compounds having a hydroxyl group having the same mixing ratio as the mixing ratio of the plasticizer in each layer of the multilayer film of the present invention). Of hydroxyl value.

  As a plasticizer contained in the layer (X) and the layer (Y), a compound having an aromatic ring such as an ether compound of a polyalkylene glycol and an aromatic alcohol or an ester compound of a polyalkylene glycol and an aromatic carboxylic acid is used. You can also Although the molecular weight of the said compound is not specifically limited, Preferably it is 200-2000, More preferably, it is 220-1500, More preferably, it is 250-1000.

  Specific examples of ether compounds of polyalkylene glycol and aromatic alcohol include polyoxyethylene phenyl ether, polyoxyethylene methyl phenyl ether, polyoxyethylene ethyl phenyl ether, polyoxyethylene n-propyl phenyl ether, polyoxyethylene i. Polyoxyethylene alkylphenyl ethers such as -propylphenyl ether, polyoxyethylene i-propylmethylphenyl ether, polyoxyethylene n-butylphenyl ether, polyoxyethylene i-butylphenyl ether, polyoxyethylene t-butylphenyl ether Can be mentioned. The polyoxyethylene alkylphenyl ether is preferably a monoether. It is also preferable that the alkyl group on the aromatic ring of the polyoxyethylene alkylphenyl ether has 4 or less carbon atoms.

  Further, as an ether compound of polyalkylene glycol and aromatic alcohol, aromatic alcohol having a plurality of aromatic rings such as polyoxyethylene monobenzyl phenyl ether, polyoxyethylene dibenzyl phenyl ether, polyoxyethylene tribenzyl phenyl ether and polyoxyethylene monobenzyl phenyl ether Also included are ether compounds with alkylene glycols. Moreover, the ether compound of aromatic alcohol and polyalkylene glycol which have condensed aromatic rings, such as polyoxyethylene naphthyl ether, is also mentioned. These ether compounds are preferably monoethers. Furthermore, the compound etherified with some polyethylene glycols, such as 2, 2-bis (4-polyoxyethylene oxyphenyl) propane, is also mentioned.

  Specific examples of ester compounds of polyalkylene glycols and aromatic carboxylic acids include esters of aromatic carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, and trimellitic acid with polyalkylene glycols such as polyethylene glycol. Compounds.

  Among the compounds having an aromatic ring described above, polyoxyethylene alkylphenyl ether, an ether compound of an aromatic alcohol having a plurality of aromatic rings and polyoxyethylene, and an ether of an aromatic alcohol having a condensed aromatic ring and a polyalkylene glycol Compounds are preferred, more preferably they are monoethers.

  Although the solubility with respect to the water of the plasticizer used in this invention is not specifically limited, It is preferable that the amount dissolved in 100 g of water at 20 ° C. is 100 g or less. When the amount of the plasticizer dissolved is in such a range, it is preferable that when the resulting multilayer film comes into contact with water, the plasticizer is less likely to be eluted by water. The amount of the plasticizer dissolved in 100 g of water at 20 ° C. is more preferably 50 g or less, further preferably 10 g or less, and particularly preferably 2 g or less.

  It is preferable that content of the plasticizer in the multilayer film of this invention is 20-100 mass parts with respect to 100 mass parts of polyvinyl acetal (I) or polyvinyl acetal (II) for every layer. If it is less than 20 mass parts, the impact resistance of the laminated glass or the laminated glass using the multilayer film as an intermediate film may be insufficient. On the other hand, when the amount exceeds 100 parts by mass, the plasticizer may bleed out and the transparency of the resulting multilayer film may be reduced, or the adhesion to glass may be impaired.

  Further, the difference between the plasticizer content relative to 100 parts by mass of the polyvinyl acetal (II) in the layer (Y) and the plasticizer content relative to 100 parts by mass of the polyvinyl acetal (I) in the layer (X) is 5 parts by mass or more. It is preferable from the viewpoint of sound insulation performance. The content difference is preferably 7.5 parts by mass or more, and more preferably 10 parts by mass or more. The difference in content is preferably 50 parts by mass or less.

  Layer (X) contains a UV absorber. The layer (X) located outside the layer (Y) containing the heat ray shielding fine particles contains an ultraviolet absorber, thereby preventing the heat ray shielding fine particles from being exposed to ultraviolet rays, and causing deterioration of the resin and particles caused by the photocatalytic activity of the particles. Can be prevented. Moreover, the ultraviolet absorber may also be contained in the layer (Y).

  The ultraviolet absorber contained in the layer (X) is not particularly limited, but 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3,5-bis ( α, α'-dimethylbenzyl) phenyl) -2H-benzotriazole, 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 Benzotriazole ultraviolet absorption such as 2-hydroxyphenyl) benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole Agents: 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl) -4-piperidyl) -2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate, 4- (3- (3,5-di-t-butyl-4-hydroxy) Hindered amines such as phenyl) propionyloxy) -1- (2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl) -2,2,6,6-tetramethylpiperidine UV absorbers; benzo such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate UV absorbers; malonic acid ester UV absorbers such as malonic acid [(4-methoxyphenyl) -methylene] -dimethyl ester, and oxalic acid anilides such as 2-ethyl-2'-ethoxy-oxalanilide Examples include ultraviolet absorbers. Examples of commercially available ultraviolet absorbers include benzotriazole ultraviolet absorbers such as Tinuvin P, Tinuvin 213, Tinuvin 234, Tinuvin 326, Tinuvin 328, Tinuvin 329, and Tinuvin 571 manufactured by Ciba Japan, and triazine ultraviolet absorbers such as Tinuvin 1577 manufactured by Ciba Japan. Examples include benzophenone-based ultraviolet absorbers such as CHIMASSORB 81 manufactured by Ciba Japan, and malonate-based ultraviolet absorbers such as Hostavin PR-25 manufactured by Clariant. These ultraviolet absorbers can be used alone or in combination of two or more. In addition, a known light stabilizer such as a hindered amine compound may be used in combination.

  Although it does not specifically limit as content of the said ultraviolet absorber in layer (X), It is preferable that it is 0.01-5 mass parts with respect to 100 mass parts of total amounts of polyvinyl acetal (I) and a plasticizer. When the addition amount is less than 0.01 parts by mass, a sufficient ultraviolet shielding effect may not be expected. More preferably, it is 0.05 mass part or more, More preferably, it is 0.1 mass part or more. Moreover, when the addition amount exceeds 5 parts by mass, the coloring of the multilayer film may be remarkably unsuitable. More preferably, it is 2 mass parts or less, More preferably, it is 1 mass part or less.

  The glass transition temperature of the resin composition containing the polyvinyl acetal (I) constituting the layer (X), the ultraviolet absorber, and the plasticizer is not particularly limited and can be appropriately selected depending on the purpose, but is 0 to 50 ° C. It is preferable that it is the range of this, It is more preferable that it is 5-45 degreeC, It is further more preferable that it is 10-40 degreeC. When the multilayer film of the present invention is used as a laminated glass interlayer, the glass transition temperature is preferably in the above range.

  The layer (Y) contains heat ray shielding fine particles for the purpose of imparting heat ray shielding properties. The heat ray shielding fine particles used in this case are not particularly limited as long as they have a property of absorbing at least light in the near-infrared wavelength region as a function. For example, tin-doped indium oxide, antimony-doped tin oxide, aluminum-doped oxidation Examples thereof include zinc, indium-doped zinc oxide, gallium-doped zinc oxide, tungsten oxide, lanthanum hexaboride, cerium hexaboride, anhydrous zinc antimonate, and copper sulfide. These may be used alone or in combination of two or more. Among these, it is preferable to contain anhydrous zinc antimonate from the viewpoints of performance, safety, raw material availability, price, and the like. The heat ray shielding fine particles may be contained in the layer (X) as necessary.

  It is preferable that the said heat ray shielding fine particle contains 0.001-5 mass parts with respect to 100 mass parts of total amounts of polyvinyl acetal (II) and a plasticizer in a layer (Y). If the content is less than 0.001 part by mass, the expected heat ray shielding effect may not be obtained. More preferably, it is 0.002 mass part or more, More preferably, it is 0.005 mass part or more. Moreover, when content exceeds 5 mass parts, there exists a possibility that the transparency of a multilayer film may be impaired. More preferably, it is 2 parts by mass or less.

  The layer (Y) contains a surfactant as a dispersant for the heat ray shielding fine particles. When the surfactant is adsorbed on the surface of the heat ray shielding fine particles, the surface is hydrophobized, and aggregation of particles generated when combined with polyvinyl acetal (II) or a plasticizer can be effectively suppressed.

  The surfactant is not particularly limited as long as it is not contrary to the gist of the present invention, but a phosphate ester is preferable. The phosphate ester is not particularly limited, and a phosphate ester of a monobasic acid or a dibasic acid is preferably used. For example, Disperbyk-102, Disperbyk-103, Disperbyk-106, Disperbyk-107, Disperbyk-108, Disperbyk-110, Disperbyk-111, Disperbyk-180, Disperbyk-182 185, Disperbyk-187, Disperbyk-190, Disperbyk-191, Disperbyk-192, Daiichi Kogyo Seiyaku Co., Ltd., PRISURF A208B, PRISURF A208F, PRISURF A212C, PRISURF A213B, PRISURF A215C, PRISURF A215C A212C, Price Surf 219B, Prisurf AL, Prisurf M208F, Adeka Coal TS-230E, Adeka Coal CS-141E, Adeka Coal CS-1361E, Adeka Coal CS-279, Adeka Coal PS-440E, Adeka Coal PS-810E, Adeka Coal PS-807, Adeka Coal PS -984 etc. are mentioned. These may be used alone or in combination of two or more.

  The content of the surfactant in the layer (Y) is preferably 0.005 to 2 parts by mass with respect to 100 parts by mass of the total amount of the polyvinyl acetal (II) and the plasticizer in the layer (Y). . If the content is less than 0.005 parts by mass, the dispersion effect may not be sufficiently obtained. More preferably, it is 0.05 mass part or more, More preferably, it is 0.1 mass part or more. Moreover, when it exceeds 2 mass parts, the bleed-out of surfactant will be remarkable and the adhesive force with respect to glass may not be hold | maintained stably. More preferably, it is 1.8 parts by mass or less.

  In the multilayer film of the present invention, the layer (Y) is likely to deteriorate due to the influence of the heat-shielding fine particles and the surfactant, so that the layer (Y) has an alkali metal salt and / or alkaline earth metal for the purpose of suppressing resin deterioration. Add salt.

  The alkali metal salt and / or alkaline earth metal salt is not particularly limited, and examples of the alkali metal and / or alkaline earth metal forming the salt include sodium, potassium, and magnesium. Examples of the acid that forms a salt include linear carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid and octanoic acid, and branched carboxylic acids such as 2-ethylbutanoic acid and 2-ethylhexanoic acid. Examples thereof include organic acids such as acids, and inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid. These may be used alone or in combination of two or more.

  The content of the alkali metal salt and / or alkaline earth metal salt in the layer (Y) is the total content of the alkali metal and / or alkaline earth metal derived from the alkali metal salt and / or alkaline earth metal salt. However, it is preferable that it is 0.006-0.2 mass part with respect to 100 mass parts of polyvinyl acetal (II). If it is less than 0.006 parts by mass, deterioration of the resin derived from the surfactant may not be sufficiently suppressed. More preferably, it is 0.008 mass part or more. Moreover, when content exceeds 0.2 mass part, aggregation of a heat ray shielding fine particle will be accelerated | stimulated and the transparency of the multilayer film obtained as a result may be lost. More preferably, it is 0.1 mass part or less.

  The glass transition temperature of the resin composition containing polyvinyl acetal (II) constituting the layer (Y), heat ray shielding fine particles, surfactant, alkali metal salt and / or alkaline earth metal salt, and plasticizer is not particularly limited. Although it can be appropriately selected depending on the purpose, it is preferably in the range of 0 to 45 ° C, more preferably 0 to 35 ° C, and further preferably 0 to 30 ° C. When the multilayer film of the present invention is used as a laminated glass interlayer, the glass transition temperature is preferably in the above range.

  Layer (X) and layer (Y) are antioxidants, adhesion improvers, pigments, dyes, stabilizers, lubricants, flame retardants, processing aids, antistatic agents, and coloring unless contrary to the gist of the present invention. Agents, impact resistance aids, fillers, moisture resistance agents, and other conventionally known additives may be included.

  The type of the antioxidant is not particularly limited, and examples thereof include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants are preferable, alkyl Substituted phenolic antioxidants are particularly preferred.

  Examples of phenolic antioxidants include 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t-amyl- Acrylate compounds such as 6- (1- (3,5-dit-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate, 2,6-dit-butyl-4-methylphenol, 2,6-dit -Butyl-4-ethylphenol, octadecyl-3- (3,5-) di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis (4-methyl-6-t-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-tert-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-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate) methane, triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) Alkyl-substituted phenolic compounds such as lopionate), 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 Triazine group-containing phenolic compounds such as -1,3,5-triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine Is mentioned.

  Examples of phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, and tris (2-t-butyl). -4-methylphenyl) phosphite, tris (cyclohexylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite, 9,10-dihydro-9-oxa-10-phos Faphenanthrene-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-phosphaf Monophosphite compounds such as nanthrene, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-ditridecyl phosphite), 4,4′-isopropylidene-bis (phenyl-dialkyl (C12 ~ C15) phosphite), 4,4'-isopropylidene-bis (diphenylmonoalkyl (C12-C15) phosphite), 1,1,3-tris (2-methyl-4-ditridecyl phosphite-5- and diphosphite compounds such as t-butylphenyl) butane and 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 blending amount of the antioxidant is not particularly limited, but is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polyvinyl acetal of the layer to be blended. .

  The method for obtaining the layer (X) constituting the multilayer film of the present invention is not particularly limited; after forming a film obtained by dissolving or dispersing polyvinyl acetal (I), an ultraviolet absorber and a plasticizer in an organic solvent, Examples include a method of distilling off the organic solvent; a method of melt-molding a resin composition containing polyvinyl acetal (I), an ultraviolet absorber and a plasticizer. Among these, the latter is preferable from the viewpoint of productivity and the like.

  When the layer (X) is obtained by the melt molding method, the method of adding the ultraviolet absorber is not particularly limited, but it is added to the polyvinyl acetal (I) in a state where the ultraviolet absorber is dissolved or suspended in advance in a plasticizer. It is preferable. Moreover, there is no restriction | limiting in particular as a method of mixing a raw material, However, Mixing by melt-kneading is preferable from viewpoints of productivity. The melt kneading method is not particularly limited, and a known kneader such as a single screw extruder, a twin screw extruder, a brabender, an open roll, or a kneader can be used. The resin temperature during melt kneading is preferably 150 to 250 ° C, more preferably 170 to 230 ° C. If the resin temperature becomes too high, the polyvinyl acetal (I) will be decomposed, and the content of volatile substances in the film after film formation will increase. On the other hand, if the temperature is too low, volatile matter removal by the kneader becomes insufficient, and the content of volatile substances in the film after film formation increases. In order to efficiently remove the volatile substance, it is preferable to remove the volatile substance from the vent port by reducing the pressure in the kneader.

  The mixed melt is melt-molded into a film. A known method can be adopted as the molding method. A film can be produced by directly attaching a T-die to the melt-kneading apparatus, or a resin composition pellet can be produced once, and then a film can be separately formed.

  The method for obtaining the layer (Y) constituting the multilayer film of the present invention is not particularly limited; polyvinyl acetal (II), heat ray shielding fine particles, surfactant, alkali metal salt and / or alkaline earth metal salt, and plastic A method in which an organic solvent is dissolved or dispersed in an organic solvent, and then the organic solvent is distilled off; polyvinyl acetal (II), heat ray shielding fine particles, surfactant, alkali metal salt and / or alkaline earth metal Examples thereof include a method of melt-molding a resin composition containing a salt and a plasticizer. Among these, the latter is preferable from the viewpoint of productivity and the like. The melt molding method preferably includes a step of melt-kneading a dispersion of a heat ray shielding fine particle and a plasticizer with respect to polyvinyl acetal (II) and forming the film into a film shape. More preferably, the metal salt and / or alkaline earth metal salt are mixed separately and then melt-molded. By mixing separately, aggregation of heat ray shielding fine particles is suppressed, and as a result, a film having a further lower haze can be obtained.

  As a method of separately mixing heat ray shielding fine particles and alkali metal salt and / or alkaline earth metal salt with respect to polyvinyl acetal (II), for example; shielding fine particles, alkali metal salt and / or alkaline earth A method of separately adding a metal salt to the polyvinyl acetal (II) as it is; a dispersion of heat ray shielding fine particles and an alkali metal salt and / or an alkaline earth metal salt separately from the polyvinyl acetal (II) A method of mixing alkali metal salt and / or alkaline earth metal salt solution and heat ray shielding fine particles separately into polyvinyl acetal (II); a dispersion of heat ray shielding fine particles, an alkali metal salt and A method of separately mixing a solution of alkaline earth metal salt with polyvinyl acetal (II); A method of mixing a molded article of polyvinyl acetal (II) with a solution of an alkali metal salt and / or alkaline earth metal salt; a molded article of polyvinyl acetal containing an alkali metal salt and / or an alkaline earth metal salt; Examples thereof include a method of mixing with a dispersion of heat ray shielding fine particles. Among these, as described above, a method of mixing the heat ray shielding fine particles as a dispersion is preferable, and the dispersion of the heat ray shielding fine particles and the alkali metal salt and / or alkaline earth metal salt solution are separately obtained from polyvinyl acetal ( The method of mixing in II) is more preferred.

  The surfactant may be added to any one of the dispersion of the heat ray shielding fine particles and the alkali metal salt and / or alkaline earth metal salt solution. From the viewpoint of the dispersibility of the heat ray shielding fine particles, at least heat rays are added. It is preferably contained in a dispersion of shielding fine particles. As a method for obtaining a dispersion of heat ray shielding fine particles containing a surfactant, a method of mixing heat ray shielding fine particles, a surfactant and a solvent followed by pulverization treatment, including heat ray shielding fine particles and a solvent, pulverization treatment was performed. Either a method of adding a surfactant to the dispersion, or a method of adding a dispersion containing heat ray shielding fine particles and a solvent and subjected to pulverization treatment to the surfactant may be used. Further, the order of mixing the dispersion of the heat ray shielding fine particles, the alkali metal salt and / or alkaline earth metal salt solution, the plasticizer and the polyvinyl acetal (II) is not particularly limited.

  The solvent contained in the dispersion of the heat ray shielding fine particles is not particularly limited, and a general-purpose organic solvent, water, a plasticizer, or the like can be used. Examples of general-purpose organic solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, ethylene glycol, diethylene glycol, hexylene glycol, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, γ-butyrolactone, ε-caprolactone, N -Methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexane, toluene, acetonitrile and the like.

  Further, the solvent contained in the alkali metal salt and / or alkaline earth metal salt solution is not particularly limited, and a solvent similar to the dispersion of the heat ray shielding fine particles can be used as the solution. An aqueous solution of an alkali metal salt and / or alkaline earth metal salt suspended in a plasticizer can also be added.

  In obtaining the layer (Y), the method of mixing the raw materials is not particularly limited, but it is preferable to mix by melt kneading from the viewpoint of productivity and the like. The method of melt kneading is not particularly limited, and the above-described kneader used for melt kneading the raw material of the layer (X) is used.

  The mixed melt is melt-molded into a film. As the forming method, the method described above as the melt forming method used for the production of the layer (X) is used.

  As a method for producing the multilayer film, a general molding method can be applied. That is, a method in which the resin composition of each layer is coextruded to a die or a feed block, a method in which each layer is separately formed into a film, and then bonded together are included.

  There is no particular limitation on the thickness of the layer (X) constituting the multilayer film of the present invention. The thickness of the layer (X) is preferably 0.05 to 1.2 mm, more preferably 0.07 to 1 mm, and still more preferably 0.1 to 0.7 mm. If the thickness is less than 0.05 mm, the mechanical strength of the multilayer film may be reduced, and if it exceeds 1.2 mm, the flexibility of the multilayer film may be insufficient. Therefore, when the thickness of the layer (X) deviates from 0.05 to 1.2 mm, the laminated film obtained when the multilayer film of the present invention is used as an interlayer film of laminated glass. The safety of the glass may be reduced.

  There is no limitation in particular in the thickness of the layer (Y) which comprises the multilayer film of this invention. The thickness of the layer (Y) is preferably 0.01 to 1 mm, more preferably 0.02 to 0.8 mm, and even more preferably 0.05 to 0.5 mm. When the thickness is less than 0.01 mm, the sound insulation performance of the laminated glass using the multilayer film of the present invention as an interlayer film of the laminated glass may be deteriorated. When the thickness exceeds 1 mm, the mechanical strength of the multilayer film cannot be expected by increasing the thickness.

  Further, the ratio (Y / X) of the thickness of the layer (Y) to the thickness of the layer (X) is not particularly limited, but is preferably 0.05 to 4 from the viewpoint of the mechanical strength and the expression of sound insulation, and is 0.07. -2 are more preferable, and 0.1-0.8 are more preferable.

  In the multilayer film of the present invention, the layer (X) is disposed on both outer sides of the layer (Y). That is, any of the outermost layers is the layer (X). In particular, when the multilayer film of the present invention is used as an interlayer film for laminated glass, if both outermost layers are layers (X), the adhesiveness between the multilayer film and the glass can be adjusted appropriately. The merit of such a layer structure is great. Examples of the layer configuration include layer (X) / layer (Y) / layer (X), layer (X) / layer (Y) / layer (X) / layer (Y) / layer (X), and the like. .

  Although there is no limitation in particular in the thickness of the multilayer film of this invention, 0.2-3 mm is preferable, 0.25-2.5 mm is more preferable, 0.3-2 mm is further more preferable. If the thickness is less than 0.2 mm, the mechanical strength may be insufficient. When thickness exceeds 3 mm, there exists a possibility that a softness | flexibility may become inadequate.

  An interlayer film for laminated glass comprising the multilayer film of the present invention is a preferred embodiment of the present invention. When the interlayer film for laminated glass of the present invention is used for an application where it is necessary to appropriately adjust the adhesiveness with glass, an adhesiveness adjusting agent may be contained in the layer (X). As the adhesion adjusting agent, conventionally known ones can be used. For example, acetic acid, propionic acid, butanoic acid, hexanoic acid, 2-ethylbutanoic acid, sodium salt of organic acid such as 2-ethylhexanoic acid, potassium salt, A magnesium salt or the like is used. These can be used alone or in combination of two or more. The optimum content of the adhesion modifier varies depending on the adhesion modifier used, but the adhesive strength of the resulting film to glass is determined by the Pummel test (described in International Publication No. WO2003 / 033583). In general, it is preferable to adjust to 3 to 10. In particular, when high penetration resistance is required, it is preferable to adjust the content to be 3 to 6, and when high anti-scattering property is required, the content is adjusted to be 7 to 10. It is preferable. When high glass scattering prevention property is required, it is also a useful method not to add an adhesion modifier. Usually, the content of the adhesion adjusting agent in the layer (X) is preferably 0.0001 to 1% by mass, more preferably 0.0005 to 0.1% by mass, and 0.001 to 0.03. More preferred is mass%.

  Moreover, a silane coupling agent is mentioned as another regulator for adjusting the said adhesiveness. As for content of the silane coupling agent in layer (X), 0.01-5 mass% is preferable.

  The shape of the surface of the interlayer film for laminated glass is not particularly limited. However, in consideration of the handleability (foam removal property) when laminating with glass, the surface in contact with the glass is melted, embossed, or the like by a conventionally known method. It is preferable that an uneven structure is formed. Although there is no restriction | limiting in particular about emboss height, It is preferable that they are 5 micrometers-500 micrometers, It is more preferable that they are 7 micrometers-300 micrometers, It is still more preferable that they are 10 micrometers-200 micrometers. When the embossing height is less than 5 μm, bubbles formed between the glass and the intermediate film may not be efficiently removed when laminating to glass, and when it exceeds 500 μm, it is difficult to form embossing. Moreover, although embossing may be given to the single side | surface of an intermediate film, and both sides may be sufficient, it is preferable to give normally to both surfaces.

  The embossed concavo-convex pattern is not particularly limited as long as the above-described specific conditions are satisfied, and may be regularly distributed or randomly distributed.

In order to form such embossing, the embossing roll method, the profile extrusion method,
An extrusion lip embossing method using a melt fracture is employed. In particular, the embossing roll method is suitable for stably obtaining an embossed film in which uniform and fine irregularities are formed.

  The embossing roll used in the embossing roll method can be produced by, for example, using an engraving mill (mother mill) having a desired concavo-convex pattern and transferring the concavo-convex pattern onto the surface of the metal roll. It can also be produced using laser etching. Further, after forming a fine concavo-convex pattern on the roll surface as described above, the surface is blasted with an abrasive such as aluminum oxide, silicon oxide, glass beads, etc. to form a finer concavo-convex pattern. You can also

  The embossing roll used in the embossing roll method is preferably subjected to a release treatment. When a roll without mold release treatment is used, troubles that cannot be peeled off from the roll are likely to occur depending on conditions. For the release treatment, known techniques such as silicone treatment, Teflon (registered trademark) treatment, plasma treatment and the like can be used.

  A laminated glass formed by bonding a plurality of glass plates using the interlayer film for laminated glass is a preferred embodiment of the present invention. The laminated glass can be produced by sandwiching the intermediate film between at least two glass plates and heating and bonding the intermediate film. The glass used for the laminated glass is not particularly limited. In addition to inorganic glass such as float plate glass, tempered plate glass, polished plate glass, mold plate glass, netted plate glass, heat ray absorbing plate glass, conventionally known polymethyl methacrylate, polycarbonate and the like. Organic glass or the like can be used. These may be colorless, colored, transparent or non-transparent. Moreover, these may be used independently and may use 2 or more types together. Although the thickness of glass is not specifically limited, It is preferable that it is 100 mm or less. The shape of the glass is not particularly limited, and may be a simple flat plate glass or a glass having a curvature such as an automobile windshield.

  The laminated glass can be produced by a conventionally known method. Examples thereof include a method using a vacuum laminator, a method using a vacuum bag, a method using a vacuum ring, and a method using a nip roll. Further, there is a method in which the obtained laminate is put into an autoclave after being temporarily pressed using these methods.

When a vacuum laminator apparatus is used, an example of the production conditions is as follows. Glass and an interlayer film are heated at a temperature of 100 to 200 ° C., particularly 130 to 160 ° C. under a reduced pressure of 1 × 10 ^{−6 to} 3 × 10 ⁻² MPa. Laminated. A method using a vacuum bag or a vacuum ring is described in, for example, European Patent No. 1235683, and is laminated at 130 to 145 ° C. under a pressure of about 2 × 10 ⁻² MPa, for example.

  As a production method using a nip roll, degassing is performed by a roll at a temperature not higher than the flow start temperature of the resin composition containing the polyvinyl acetal (I), ultraviolet absorber and plasticizer used for the production of the layer (X) described above. Then, a method of performing pressure bonding at a temperature close to the flow start temperature can be mentioned. Specifically, for example, a method of heating to 30 to 70 ° C. with an infrared heater or the like, then degassing with a roll, and further heating to 50 to 120 ° C. followed by pressure bonding with the roll can be mentioned.

  When pressure bonding is performed using the above-described method, and then further pressure bonding is performed, the operating conditions of the autoclave process are appropriately selected depending on the thickness and configuration of the laminated glass, for example, 1.0 to 1.5 MPa It is preferable to perform the treatment at a temperature of 130 to 145 ° C for 0.5 to 3 hours under pressure.

The multilayer film of the present invention is less colored by heating and less foreign matter (undissolved content). Therefore, the multilayer film of the present invention is excellent in recyclability. Hereinafter, the manufacturing method of the film using the collection | recovery of the said multilayer film is demonstrated.

A method for producing a monolayer film in which a multilayer film recovery product of the present invention (hereinafter, the “multilayer film recovery product of the present invention” may be abbreviated as “collection product”) is melt-kneaded and then formed into a film. Is also a preferred embodiment of the present invention. At this time, the recovered product has a degree of acetalization of 55 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 15 mol%, and the following formulas (1) and (2): It is more preferable to form a film after melt-kneading the polyvinyl acetal (III) to be filled and the plasticizer.
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)
Where
A: Peak top molecular weight measured by a differential refractive index detector when polyvinyl acetal (III) heated at 230 ° C. for 3 hours was measured by gel permeation chromatography B: Polyvinyl acetal heated at 230 ° C. for 3 hours Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when (III) is subjected to gel permeation chromatography measurement: absorbance at peak top molecular weight (B).

  The peak top molecular weight (A), the peak top molecular weight (B) and the absorbance (b) at the peak top molecular weight of the polyvinyl acetal (III) are determined in the same manner as in the method for determining those values in the polyvinyl acetal (I) described above.

  The viscosity average polymerization degree of the polyvinyl acetal (III) is preferably 200 to 5,000. When the viscosity average polymerization degree is less than 200, there is a possibility that the practical strength of polyvinyl acetal cannot be obtained. The viscosity average degree of polymerization is more preferably 250 or more, further preferably 300 or more, and particularly preferably 400 or more. On the other hand, when the viscosity average degree of polymerization exceeds 5000, the melt viscosity may become too high and film formation may be difficult. The viscosity average degree of polymerization is more preferably 4500 or less, further preferably 4000 or less, and particularly preferably 3500 or less.

  The degree of acetalization of polyvinyl acetal (III) is 55 to 85 mol%. When the degree of acetalization is less than 55 mol%, the compatibility with a plasticizer or the like decreases. Moreover, there exists a possibility that the foreign material (undissolved part) in the obtained multilayer film may increase. The degree of acetalization is preferably 60 mol% or more, more preferably 65 mol% or more. On the other hand, when the degree of acetalization exceeds 85 mol%, the efficiency of the acetalization reaction is significantly reduced. Moreover, there exists a possibility that the film obtained may become easy to color. The degree of acetalization is preferably 80 mol% or less.

  Content of the vinyl-ester monomer unit of polyvinyl acetal (III) is 0.1-15 mol%. When the content of the vinyl ester monomer unit is less than 0.1 mol%, the polyvinyl acetal cannot be stably produced and the film cannot be formed. The content of the vinyl ester monomer unit is preferably 0.7 mol% or more, more preferably 6 mol% or more, and further preferably 7 mol% or more. On the other hand, when the content of the vinyl ester monomer unit exceeds 15 mol%, the resulting film is colored. The content of the vinyl ester monomer unit is preferably 13 mol% or less, more preferably 10 mol% or less. Moreover, when using polyvinyl acetal (III) for the multilayer film using the said collection | recovery mentioned later, when a content of a vinyl ester monomer unit exists in these ranges, a layer (Y ') is a soft layer. Thus, the obtained multilayer film has excellent sound insulation performance while maintaining practical mechanical strength.

  The content of the vinyl alcohol monomer unit of the polyvinyl acetal (III) used in the present invention is preferably 5 to 44.9 mol%.

  The content of monomer units other than acetalized monomer units, vinyl ester monomer units and vinyl alcohol monomer units in the polyvinyl acetal (III) used in the present invention is preferably 20 mol. % Or less, more preferably 10 mol% or less, and further preferably 5 mol% or less.

  The polyvinyl acetal (III) used in the present invention is preferably produced in the same manner as described above as a method for producing the polyvinyl acetal (I) and the polyvinyl acetal (II).

  As polyvinyl acetal (III), it is preferable to use the above-mentioned polyvinyl acetal (I) and polyvinyl acetal (II). From the viewpoint of further improving the strength of the single layer film, it is preferable to use polyvinyl acetal (I) as polyvinyl acetal (III).

  Usually, the film formation of polyvinyl acetal is carried out, for example, in a film formation apparatus in which an extruder is equipped with a measuring machine such as a gear pump and a die such as a T die. Generally, in film formation, both ends (trims) of the film are cut off. It is very important to collect and reuse such trims from the viewpoints of energy saving, effective utilization of resources and improvement of yield. In addition, off-spec products that are difficult to use as products produced when manufacturing films with irregularities on the surface and off-spec products that are difficult to use as products due to non-uniform composition and thickness are also the same as trim It is useful because it can be reused. When the polyvinyl acetal (I) and the polyvinyl acetal (II) used in the multilayer film of the present invention are used, the formation of coarse particles is suppressed during the acetalization reaction, and as a result, the resulting polyvinyl acetal is melt-formed. In addition, a film with reduced foreign matter (undissolved content) can be obtained. Moreover, since the multilayer film of the present invention is less colored when heat-treated, it is possible to effectively reuse the collected materials such as the trim and off-spec products.

  As the plasticizer newly added to the recovered material, those described above as used in the production of the layer (X) are used. As the plasticizer to be newly added, any of the aforementioned plasticizers can be used as long as the resulting single layer film has excellent transparency. When the amount of the recovered product exceeds 50 parts by mass with respect to 100 parts by mass of newly added polyvinyl acetal (III), 10 parts by mass or more of the added plasticizer is an aliphatic ester having a hydroxyl group. It is preferable to use a compound, an aliphatic ether compound having a hydroxyl group, an aliphatic polyester compound having a hydroxyl group, a monoether compound of a polyalkylene glycol and an aromatic alcohol, or a monoester compound of a polyalkylene glycol and an aromatic carboxylic acid.

  The ratio of the amount of the recovered product and the newly added polyvinyl acetal (III) is not particularly limited and can be arbitrarily changed. Usually, the recovered material is 1 to 10000 parts by mass with respect to 100 parts by mass of polyvinyl acetal (III).

  Although content of the plasticizer added with respect to the said recovered material is not specifically limited, It is preferable that it is 20-100 mass parts with respect to 100 mass parts of polyvinyl acetal (III) newly added. If it is less than 20 mass parts, the impact resistance of the film obtained and the laminated glass manufactured using the said film may become inadequate. On the other hand, if it exceeds 100 parts by mass, the plasticizer may bleed out, and the transparency of the resulting film may be lowered, or the adhesion to glass may be impaired.

  As the melt-kneading method and the film forming method employed in the method for producing a single layer film using the recovered material, the method described above as the method used when producing the layer (X) is used. As a method of feeding the recovered material back into the extruder, a method in which a film of a trim or off-spec product is wound around a roll is unwound as it is and then fed back into the extruder; the trim or off-spec product is taken up on a roll For example, there is a method of cutting the cake into a certain size and then re-feeding it into the extruder.

  When reusing collected materials such as trims or off-spec products, adjust the amount of polyvinyl acetal (III), plasticizer, and other components to the extruder while analyzing the newly obtained film components. A desired film can be obtained while adjusting the amount of each added.

  Although the thickness of the single layer film obtained by the manufacturing method using the said recovered material is not specifically limited, It is preferable that it is 0.05-5.0 mm, It is more preferable that it is 0.1-2.0 mm, 0 More preferably, it is 1-1.2 mm.

  An interlayer film for laminated glass composed of a single layer film obtained by the production method using the recovered material is also a preferred embodiment of the present invention. The single layer film is less colored. Moreover, since the said single layer film has few foreign materials (undissolved part), the said single layer film is excellent in transparency. Therefore, the single layer film is useful as an interlayer film for laminated glass. A laminated glass obtained by bonding a plurality of glass plates using the interlayer film for laminated glass is also a preferred embodiment of the present invention. The said laminated glass can be manufactured by the method mentioned above as a manufacturing method of the laminated glass which used the multilayer film of this invention as an intermediate film.

  The haze of the laminated glass thus obtained is preferably 1.0 or less. In the present invention, the haze of the laminated glass is measured according to JIS K7105.

Polyvinyl acetal having a degree of acetalization of 55 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 15 mol%, and satisfying the following formulas (1) and (2): (III) Polyvinyl acetal on both outer sides of the layer (Y ′) formed by melt-kneading the plasticizer, heat ray shielding fine particles, surfactant, and alkali metal salt and / or alkaline earth metal salt. A method for producing a multilayer film in which the layer (X) formed by melt-kneading (I), an ultraviolet absorber and a plasticizer and then forming a film is also a preferred embodiment of the present invention.
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)

Where
A: Peak top molecular weight B measured with a differential refractive index detector when GPC measurement is performed on polyvinyl acetal (III) heated at 230 ° C. for 3 hours: Polyvinyl acetal (III) heated at 230 ° C. for 3 hours Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when GPC measurement is performed: Absorbance at peak top molecular weight (B).

  Here, as polyvinyl acetal (III), what was mentioned above as what is used for the monolayer film obtained using the said collection | recovery thing is used. As polyvinyl acetal (III), it is preferable to use the above-mentioned polyvinyl acetal (I) and polyvinyl acetal (II). From the viewpoint of further improving sound insulation, it is preferable to use polyvinyl acetal (II) as polyvinyl acetal (III).

  As the plasticizer, heat ray shielding fine particles, surfactant, alkali metal salt and alkaline earth metal salt added to the recovered material, those described above as those used for the production of the layer (Y) are used.

  Any of the plasticizers described above as used for the production of the layer (Y) can be used as long as the resulting single layer film has excellent transparency. When the amount of the recovered product exceeds 50 parts by mass with respect to 100 parts by mass of newly added polyvinyl acetal (III), 10 parts by mass or more of the added plasticizer is an aliphatic ester having a hydroxyl group. It is preferable to use a compound, an aliphatic ether compound having a hydroxyl group, an aliphatic polyester compound having a hydroxyl group, a monoether compound of a polyalkylene glycol and an aromatic alcohol, or a monoester compound of a polyalkylene glycol and an aromatic carboxylic acid.

  The ratio of the amount of the recovered product and the newly added polyvinyl acetal (III) is not particularly limited and can be arbitrarily changed. Usually, the recovered material is 1 to 10000 parts by mass with respect to 100 parts by mass of polyvinyl acetal (III).

  The amount of the plasticizer to be newly added is preferably 20 to 100 parts by mass with respect to 100 parts by mass of the newly added polyvinyl acetal (III). If it is less than 20 mass parts, the impact resistance of a multilayer film and the laminated glass obtained may become inadequate. On the other hand, when the amount exceeds 100 parts by mass, the plasticizer may bleed out and the transparency of the resulting multilayer film may be reduced, or the adhesion to glass may be impaired.

  The addition amount of the heat ray shielding fine particles is preferably 0.001 to 2 parts by mass with respect to 100 parts by mass of the total amount of the plasticizer and polyvinyl acetal (III) to be newly added. If the content is 0.001 part by mass or less, the expected heat ray shielding effect may not be obtained. More preferably, it is 0.002 mass part or more, More preferably, it is 0.005 mass part or more. Moreover, when content exceeds 2 mass parts, there exists a possibility that transparency of the multilayer film obtained may be impaired. More preferably, it is 1.5 mass parts or less, More preferably, it is 1 mass part or less.

  The addition amount of the surfactant is preferably 0.005 to 2 parts by mass with respect to 100 parts by mass of the total amount of polyvinyl acetal (III) and plasticizer to be newly added. When the content is less than 0.005 parts by mass, the effect of dispersing the heat ray shielding fine particles may not be sufficiently obtained. More preferably, it is 0.05 mass part or more, More preferably, it is 0.1 mass part or more. Moreover, when it exceeds 2 mass parts, the bleed-out of surfactant will be remarkable and the adhesive force with respect to glass may not be hold | maintained stably. More preferably, it is 1.8 parts by mass or less.

  The amount of the alkali metal salt and / or alkaline earth metal salt added to the recovered material is the content of the alkali metal and / or alkaline earth metal derived from the alkali metal salt and / or alkaline earth metal salt. Is preferably 0.006 to 0.2 parts by mass with respect to 100 parts by mass of polyvinyl acetal (III). If it is less than 0.006 parts by mass, deterioration of the resin derived from the surfactant may not be sufficiently suppressed. More preferably, it is 0.008 mass part or more. Moreover, when content exceeds 0.2 mass part, aggregation of a heat ray shielding fine particle will be accelerated | stimulated and the transparency of the multilayer film obtained as a result may be lost. More preferably, it is 0.1 mass part or less, More preferably, it is 0.04 mass part or less.

  The layer (Y ′) can be produced by the method described above as the production method of the layer (Y), except that polyvinyl acetal (III) and the recovered material are used instead of polyvinyl acetal (II). Here, as a method of charging the recovered material into the extruder again, a method in which a film of a trim or off-spec product is wound on a roll is unwound as it is and then re-entered into the extruder; the trim or off-spec product is rolled. For example, a method of cutting the wound material into a certain size and then re-feeding it into the extruder may be mentioned. The multilayer film using the recovered material is the method described above as the method for producing a laminated film having the layer (X) and the layer (Y) except that the layer (Y ′) is used instead of the layer (Y). It can be manufactured in the same manner.

  The multilayer structure and thickness of the multilayer film using the recovered material are the multilayer film having the layer (X) and the layer (Y) described above, except that the layer (Y ′) is used instead of the layer (Y). The same.

  An interlayer film for laminated glass comprising a multilayer film obtained by the method for producing a multilayer film using the recovered material is a preferred embodiment of the present invention. Since the multilayer film using the recovered material has few foreign matters (undissolved content), the multilayer film is excellent in transparency. Therefore, the multilayer film is useful as an interlayer film for laminated glass. A laminated glass obtained by bonding a plurality of glass plates using the interlayer film for laminated glass is also a preferred embodiment of the present invention. The said laminated glass can be manufactured by the method mentioned above as a manufacturing method of the laminated glass which used the multilayer film which has layer (X) and layer (Y) as an intermediate film. The haze of the laminated glass thus obtained is preferably 1.0 or less.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. “Polymerization degree” means “viscosity average polymerization degree”.

[Synthesis of polyvinyl acetate]
PVAc-1
A 6 L separable flask equipped with a stirrer, thermometer, nitrogen introduction tube, and reflux tube was deoxygenated in advance, and vinyl acetate monomer (VAM) 2555 g containing 500 ppm acetaldehyde (AA) and 50 ppm acetaldehyde dimethyl acetal (DMA). 945 g of methanol (MeOH) containing 50 ppm of acetaldehyde dimethyl acetal and an acetaldehyde content of less than 1 ppm; 1% methanol solution of tartaric acid in an amount of 20 ppm of tartaric acid in the vinyl acetate monomer was charged. While blowing nitrogen into the flask, the temperature inside the flask was adjusted to 60 ° C. In addition, -10 degreeC ethylene glycol / water solution was circulated through the reflux pipe. A 0.55 mass% methanol solution of di-n-propyl peroxydicarbonate was prepared, and 18.6 mL was added into the flask to initiate polymerization. The amount of di-n-propyl peroxydicarbonate added at this time was 0.081 g. A methanol solution of di-n-propyl peroxydicarbonate was sequentially added at a rate of 20.9 mL / hour until the completion of polymerization. During the polymerization, the temperature in the flask was kept at 60 ° C. Four hours after the start of polymerization, when the solid content concentration of the polymerization solution reached 25.1%, 0.0141 g of sorbic acid (3% of di-n-propyl peroxydicarbonate remaining undecomposed in the polymerization solution) was obtained. After adding 1200 g of contained methanol (corresponding to a molar equivalent), the polymerization solution was cooled to stop the polymerization. When the polymerization was stopped, the polymerization rate of the vinyl acetate monomer was 35.0%. After the polymerization solution was cooled to room temperature, the inside of the flask was depressurized using a water aspirator to distill off the vinyl acetate monomer and methanol, thereby precipitating polyvinyl acetate. 3000 g of methanol was added to the precipitated polyvinyl acetate, and the polyvinyl acetate was dissolved while heating at 30 ° C., and then the inside of the flask was decompressed again using a water aspirator to distill off the vinyl acetate monomer and methanol. Thus, polyvinyl acetate was precipitated. The operation of dissolving polyvinyl acetate in methanol and then precipitating it was further repeated twice. Methanol was added to the precipitated polyvinyl acetate to obtain a 40% by mass methanol solution of polyvinyl acetate (PVAc-1) with a vinyl acetate monomer removal rate of 99.8%.

  The polymerization degree was measured using a part of the methanol solution of PVAc-1 obtained. To a methanol solution of PVAc-1, a 10% methanol solution of sodium hydroxide was added so that the molar ratio of sodium hydroxide to vinyl acetate units in polyvinyl acetate was 0.1. When the gelled product was formed, the gel was pulverized and subjected to Soxhlet extraction with methanol for 3 days. The obtained polyvinyl alcohol was dried and subjected to viscosity average polymerization degree measurement. The degree of polymerization was 1700.

PVAc-2 to PVAc-12
Except having changed into the conditions described in Table 1, polyvinyl acetate (PVAc-2 to PVAc-12) was obtained by the same method as PVAc-1. In Table 1, “ND” means less than 1 ppm. The polymerization degree of each obtained polyvinyl acetate was calculated | required similarly to PVAc-1. The results are shown in Table 1.

[Synthesis of polyvinyl alcohol]
PVA-1
Water with respect to vinyl acetate monomer units in methanol and polyvinyl acetate so that the total solid concentration (saponification concentration) is 30% by mass with respect to a 40% by mass methanol solution of polyvinyl acetate of PVAc-1. An 8% methanol solution of sodium hydroxide was added with stirring so that the molar ratio of sodium oxide was 0.020, and the saponification reaction was started at 40 ° C. The gel is pulverized when the gelated product is generated as the saponification reaction proceeds, and the crushed gel is transferred to a container at 40 ° C. When 60 minutes have elapsed from the start of the saponification reaction, methanol / methyl acetate / water ( 25/70/5 mass ratio) solution and neutralized. The obtained swollen gel was centrifuged, and methanol twice as much as the swollen gel was added, immersed, left for 30 minutes, and then centrifuged four times, 60 ° C. for 1 hour, 100 PVA-1 was obtained by drying at 2 ° C. for 2 hours.

  The polymerization degree and saponification degree of PVA-1 were determined by the method described in JIS-K6726. The degree of polymerization was 1700, and the degree of saponification was 99.1 mol%. These physical property data are also shown in Table 2.

  After ashing PVA-1, the sodium acetate content of PVA-1 was calculated | required by measuring the amount of sodium in the obtained ash using the ICP emission-analysis apparatus "IRISAP" by Jarrel Ash. . The sodium acetate content was 0.7% (0.20% in terms of sodium). These physical property data are also shown in Table 2.

PVA-2-5, comparative PVA-1-3
Each PVA was synthesize | combined like PVA-1 except having changed into the conditions shown in Table 2. The polymerization degree, saponification degree, and sodium acetate content (in terms of sodium mass) of the obtained PVA were measured in the same manner as PVA-1. The results are shown in Table 2.

PVA-6, comparative PVA-4 and 5
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 3 were changed. The polymerization degree, saponification degree, and sodium acetate content (in terms of sodium mass) of the obtained PVA were measured in the same manner as PVA-1. The results are shown in Table 3.

PVA-7, comparative PVA-6 and 7
Each PVA was synthesized in the same manner as PVA-1 except that the conditions shown in Table 4 were changed. The polymerization degree, saponification degree, and sodium acetate content (in terms of sodium mass) of the obtained PVA were measured in the same manner as PVA-1. The results are shown in Table 4.

PVA-8-11, comparative PVA-8 and 9
Each PVA was synthesized in the same manner as PVA-1 except that the conditions shown in Table 5 were changed. The polymerization degree, saponification degree, and sodium acetate content (in terms of sodium mass) of the obtained PVA were measured in the same manner as PVA-1. The results are shown in Table 5.

PVA-12, comparative PVA-10 and 11
Each PVA was synthesized in the same manner as PVA-1 except that the conditions shown in Table 6 were changed. The polymerization degree, saponification degree, and sodium acetate content (in terms of sodium mass) of the obtained PVA were measured in the same manner as PVA-1. The results are shown in Table 6.

PVA-13, comparative PVA-12 and 13
Each PVA was synthesized in the same manner as PVA-1, except that the conditions were changed to those shown in Table 7. The polymerization degree, saponification degree, and sodium acetate content (in terms of sodium mass) of the obtained PVA were measured in the same manner as PVA-1. The results are shown in Table 7.

[Synthesis of PVB]
PVB-1
A 10-liter glass container equipped with a reflux condenser, thermometer, and squid type stirring blade was charged with 8100 g of ion-exchanged water and 660 g of PVA-1 (PVA concentration 7.5%), and the content was raised to 95 ° C. Warm to completely dissolve the PVA. Next, the contents are gradually cooled to 10 ° C. over about 30 minutes while stirring at 120 rpm, and then 384 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid are added to the vessel, and a butyralization reaction is performed for 150 minutes. It was. Thereafter, the temperature was raised to 60 ° C. over 60 minutes, held at 60 ° C. for 120 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water and then neutralized by adding an excessive amount of aqueous sodium hydroxide solution. Subsequently, the resin was rewashed with ion-exchanged water and then dried to obtain PVB-1.

[Composition of PVB]
The degree of butyralization (degree of acetalization) of PVB-1, the content of vinyl acetate monomer units, and the content of vinyl alcohol monomer units were measured according to JIS K6728. The degree of butyralization (degree of acetalization) was 68.2 mol%, the content of vinyl acetate monomer units was 0.9 mol%, and the content of vinyl alcohol monomer units was 30.9 mol%. It was. The results are also shown in Table 8.

[GPC measurement of PVB]

(measuring device)
GPC measurement was performed using “GPCmax” manufactured by VISCOTECH. As a differential refractive index detector, “TDA305” manufactured by VISCOTECH was used. “UV Detector 2600” manufactured by VISCOTECH was used as an ultraviolet-visible absorption detector. The optical path length of the detection cell of the absorptiometric detector is 10 mm. “GPC HFIP-806M” manufactured by Showa Denko KK was used for the GPC column. Moreover, OmniSEC (Version 4.7.0.406) attached to the apparatus was used as analysis software.

(Measurement condition)
A sample prepared by the above-described method was dissolved in 20 mmol / l sodium trifluoroacetate-containing hexafluoroisopropanol (hereinafter abbreviated as “HFIP”) to prepare a 1.00 mg / ml solution of PVA. The solution was filtered through a 0.45 μm polytetrafluoroethylene filter and used for measurement.

  As the mobile phase, HFIP containing 20 mmol / l sodium trifluoroacetate was used. The mobile phase flow rate was 1.0 ml / min. The sample injection amount was 100 μl, and measurement was performed at a GPC column temperature of 40 ° C.

In addition, the sample in which the viscosity average polymerization degree of PVA exceeded 2400 performed GPC measurement using the sample (100 microliters) diluted suitably. The absorbance at a sample concentration of 1.00 mg / ml was calculated from the measured value according to the following formula. α (mg / ml) is the concentration of the diluted sample.

Absorbance at a sample concentration of 1.00 mg / ml = (1.00 / α) × measured value of absorbance

(Create a calibration curve)
As a standard, polymethyl methacrylate (hereinafter abbreviated as “PMMA”) manufactured by Agilent Technologies (peak top molecular weight: 1944000, 790000, 467400, 271400, 144000, 79250, 35300, 13300, 7100, 1960, 1020, 690) And a calibration curve for converting the elution volume into the PMMA molecular weight was prepared for each of the differential refractive index detector and the absorptiometric detector. The analytical software was used to create each calibration curve. In this measurement, a column in a state where the peaks of the standard samples having both molecular weights of 1944000 and 271400 can be separated in the measurement of polymethyl methacrylate was used.

  In this apparatus, the peak intensity obtained from the differential refractive index detector is expressed in mV (millivolt), and the peak intensity obtained from the UV detector is expressed in absorbance (abs unit: Absorbance unit).

(Sample preparation)
The obtained powdery PVB-1 was hot-pressed at a pressure of 2 MPa and 230 ° C. for 3 hours to obtain a heated polyvinyl acetal (film). At this time, the thickness of the film was 760 μm. This was used for GPC measurement.

(Measurement)
The obtained sample was subjected to GPC measurement by the above method. FIG. 1 is a graph showing the relationship between the molecular weight and the value measured with a differential refractive index detector, and the relationship between the molecular weight and the absorbance measured with an absorptiometric detector (measurement wavelength 280 nm). The molecular weight at this time is one converted from the elution volume using a calibration curve (PMMA equivalent molecular weight). The peak top molecular weight (A) measured with the differential refractive index detector obtained from FIG. 1 was 90000, and the peak top molecular weight (B) measured with the absorptiometric detector (280 nm) was 68900. The obtained value is expressed by the following formula (AB) / A
The value obtained by substituting for was 0.23. The absorbance (b) at the peak top molecular weight (B) was 2.21 × 10 ⁻³ . The ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn obtained from the chromatogram (RI) in FIG. 1 was 3.4. These results are also shown in Table 8.

The peak top molecular weight (C) measured by an absorptiometric detector (320 nm) obtained in the same manner as the method for obtaining the peak top molecular weight (B) was 60000. The peak top molecular weight (A) and the peak top molecular weight (C) are expressed by the following formula (AC) / A
The value obtained by substituting for was 0.33. The absorbance (c) at the peak top molecular weight (C) was 1.26 × 10 ⁻³ . These results are also shown in Table 8.

PVB-2 ~ 5
PVB was synthesized and evaluated in the same manner as PVB-1, except that the raw material PVA was changed to that shown in Table 8. The results are shown in Table 8.

PVB-6
PVB was synthesized and evaluated in the same manner as PVB-1, except that the amount of n-butyraldehyde added was changed to 320 g. The results are shown in Table 8.

PVB-7
PVB was synthesized and evaluated in the same manner as PVB-1, except that the amount of n-butyraldehyde added was changed to 362 g. The results are shown in Table 8.

PVB-8
Polyvinyl butyral was synthesized and evaluated in the same manner as PVB-1, except that the amount of n-butyraldehyde added was changed to 449 g. The results are shown in Table 8.

Comparative PVB-1-3
Polyvinyl butyral was synthesized and evaluated in the same manner as PVB-1, except that the raw material PVA was changed to that shown in Table 8. The results are shown in Table 8.

Comparative PVB-4
Polyvinyl butyral was synthesized and evaluated in the same manner as PVB-6 except that the raw material PVA was changed to comparative PVA-1. The results are shown in Table 8.

Comparative PVB-5
Polyvinyl butyral was synthesized and evaluated in the same manner as PVB-8 except that the raw material PVA was changed to comparative PVA-1. The results are shown in Table 8.

Comparative PVB-6
Polyvinyl butyral was synthesized and evaluated in the same manner as PVB-6 except that the raw material PVA was changed to comparative PVA-2. The results are shown in Table 8.

Comparative PVB-7
Polyvinyl butyral was synthesized and evaluated in the same manner as PVB-8 except that the raw material PVA was changed to comparative PVA-2. The results are shown in Table 8.

PVB-9
Into a 10 liter glass container equipped with a reflux condenser, thermometer, and squid type stirring blade, 8234 g of ion-exchanged water and 526 g of PVA-6 were charged (PVA concentration 6.0%), and the contents were raised to 95 ° C. Warm to dissolve completely. Next, the contents are gradually cooled to 15 ° C. over about 30 minutes while stirring at 120 rpm, and then 307 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid are added to the vessel, and a butyralization reaction is performed for 120 minutes. It was. Thereafter, the temperature was raised to 60 ° C. over 60 minutes, held at 60 ° C. for 120 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water and then neutralized by adding an excessive amount of aqueous sodium hydroxide solution. Subsequently, it was rewashed with ion-exchanged water and dried to obtain polyvinyl butyral.

  The composition of the obtained polyvinyl butyral was measured in the same manner as PVB-1. The degree of butyralization (degree of acetalization) was 68.2 mol%, the content of vinyl acetate monomer units was 1.3 mol%, and the content of vinyl alcohol monomer units was 30.5 mol%. It was. Next, GPC measurement of the obtained PVB-9 was performed in the same manner as PVB-1. Table 9 shows the evaluation results.

Comparative PVB-8 and 9
Except having changed raw material PVA into what is shown in Table 9, synthesis and evaluation of PVB were implemented like PVB-9. The results are shown in Table 9.

PVB-10
A 10-liter glass container equipped with a reflux condenser, thermometer, and squid-type stirring blade was charged with 8322 g of ion-exchanged water and 438 g of PVA-7 (PVA concentration 5.0%), and the contents were raised to 95 ° C. Warm to completely dissolve the PVA. Next, the contents are gradually cooled to 20 ° C. over about 30 minutes while stirring at 120 rpm, and then 256 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid are added to the vessel, and a butyralization reaction is performed for 120 minutes. It was. Thereafter, the temperature was raised to 60 ° C. over 60 minutes, held at 60 ° C. for 120 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water and then neutralized by adding an excessive amount of aqueous sodium hydroxide solution. Subsequently, PVB was obtained by re-washing with ion-exchanged water and drying.

  The composition of the obtained PVB was measured in the same manner as PVB-1. The degree of butyralization (degree of acetalization) was 68.1 mol%, the content of vinyl acetate monomer units was 1.5 mol%, and the content of vinyl alcohol monomer units was 30.4 mol%. It was. Next, GPC measurement of the obtained PVB-10 was performed in the same manner as PVB-1. Table 10 shows the evaluation results.

Comparative PVB-10 and 11
Except having changed raw material PVA into what is shown in Table 10, synthesis and evaluation of PVB were implemented like PVB-10. The results are shown in Table 10.

PVB-11
A 10-liter glass container equipped with a reflux condenser, thermometer, and squid type stirring blade was charged with 8100 g of ion-exchanged water and 660 g of PVA-8 (PVA concentration 7.5%), and the contents were raised to 95 ° C. Warm to dissolve completely. Next, the contents are gradually cooled to 15 ° C. over about 30 minutes while stirring at 120 rpm. Then, 432 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid are added to the vessel, and a butyralization reaction is performed for 90 minutes. It was. Thereafter, the temperature was raised to 45 ° C. over 30 minutes, held at 45 ° C. for 180 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water and then neutralized by adding an excessive amount of aqueous sodium hydroxide solution. Subsequently, PVB was obtained by re-washing with ion-exchanged water and drying.

  The composition of the obtained PVB was measured in the same manner as PVB-1. The degree of butyralization (degree of acetalization) was 74.1 mol%, the content of vinyl acetate monomer units was 8.1 mol%, and the content of vinyl alcohol monomer units was 17.8 mol%. It was. GPC measurement of the obtained PVB-11 was performed in the same manner as PVB-1. The evaluation results are shown in Table 11.

PVB-12-14
PVB was synthesized and evaluated in the same manner as PVB-11 except that the raw material PVA was changed to that shown in Table 11. The results are shown in Table 11.

PVB-15
PVB was synthesized and evaluated in the same manner as PVB-11 except that the amount of n-butyraldehyde added was changed to 458 g. The results are shown in Table 11.

Comparative PVB-12 and 13
PVB was synthesized and evaluated in the same manner as PVB-11 except that the raw material PVA was changed to that shown in Table 11. The results are shown in Table 11.

Comparative PVB-14 and 15
Except having changed raw material PVA into what is shown in Table 11, synthesis and evaluation of PVB were implemented like PVB-15. The results are shown in Table 11.

PVB-16
A 10L liter glass container equipped with a reflux condenser, thermometer and squid type stirring blade was charged with 8234g of ion-exchanged water and 526g of PVA-12 (PVA concentration 6.0%), and the contents were raised to 95 ° C. Warm to completely dissolve the PVA. Next, the contents are gradually cooled to 15 ° C. over about 60 minutes while stirring at 120 rpm, and then 344 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid are added to the vessel, and a butyralization reaction is performed for 90 minutes. It was. Thereafter, the temperature was raised to 45 ° C. over 30 minutes, held at 45 ° C. for 180 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water and then neutralized by adding an excessive amount of aqueous sodium hydroxide solution. Subsequently, PVB was obtained by re-washing with ion-exchanged water and drying.

  The composition of the obtained PVB was measured in the same manner as PVB-1. The degree of butyralization (degree of acetalization) was 74.6 mol%, the content of vinyl acetate monomer units was 8.3 mol%, and the content of vinyl alcohol monomer units was 17.1 mol%. It was. GPC measurement of the obtained PVB-16 was performed in the same manner as PVB-1. The evaluation results are shown in Table 12.

Comparative PVB-16 and 17
PVB was synthesized and evaluated in the same manner as PVB-16, except that the raw material PVA was changed to that shown in Table 12. The results are shown in Table 12.

PVB-17
A 10-liter glass container equipped with a reflux condenser, thermometer, and squid type stirring blade was charged with 8234 g of ion-exchanged water and 438 g of PVA-13 (PVA concentration 5.0%), and the contents were raised to 95 ° C. Warm to completely dissolve the PVA. Next, the contents are gradually cooled to 15 ° C. over about 60 minutes while stirring at 120 rpm, and then 265 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid are added to the vessel, and a butyralization reaction is performed for 90 minutes. It was. Thereafter, the temperature was raised to 45 ° C. over 30 minutes, held at 45 ° C. for 180 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water and then neutralized by adding an excessive amount of aqueous sodium hydroxide solution. Subsequently, PVB was obtained by re-washing with ion-exchanged water and drying.

  The composition of the obtained PVB was measured in the same manner as PVB-1. The degree of butyralization (average degree of acetalization) of PVB is 73.2 mol%, the content of vinyl acetate monomer units is 8.1 mol%, and the content of vinyl alcohol monomer units is 18.7 mol%. %Met. GPC measurement of the obtained PVB-17 was performed in the same manner as PVB-1. The evaluation results are shown in Table 13.

Comparative PVB-18 and 19
PVB was synthesized and evaluated in the same manner as PVB-17 except that the raw material PVA was changed to that shown in Table 13. The results are shown in Table 13.

Example 1
[Production of Layer (X)]
50 parts by mass of the synthesized PVB-1 powder, 19 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer, and 0.175 parts by mass of “Tinuvin 328” manufactured by Ciba Japan as an ultraviolet absorber, Using a Labo plast mill “C model” manufactured by Toyo Seiki Seisakusho Co., Ltd., melt kneading was performed at 170 ° C. and 50 rpm for 5 minutes. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 320 μm.

[Preparation of layer (Y)]
A zinc antimonate methanol dispersion with a concentration of 60% by mass was prepared by pulverizing ZnSb ₂ O ₆ anhydrous zinc antimonate methanol dispersion (Nissan Chemical Co., Ltd. “CX-Z693M-F”) with a bead mill. . 1.62 parts by mass of the resulting dispersion, 0.24 parts by mass of “DISPERBYK-102” manufactured by Big Chemie as phosphate ester, and 12.1 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer 25 mass% aqueous solution 0.10 of the dispersion liquid obtained by the above, 12.2 mass parts of triethylene glycol di-2-ethylhexanoate, a mixture of magnesium acetate and potassium acetate (mixing mass ratio: 2/1) Mass parts and 43 parts by mass of the synthesized PVB-11 powder were melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using the Laboplast mill. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 120 μm.

[Production of laminated film]
Layer (X) and layer (Y) are layered in the order of layer (X) / layer (Y) / layer (X), and pressed in a form of 760 μm under conditions of 135 ° C. and 10 kg / cm ^2. A laminated film consisting of (X) (320 μm) / layer (Y) (120 μm) / layer (X) (320 μm) was obtained.

[Undissolved content in the film]
The obtained laminated film was sandwiched between two transparent glass plates (20 cm × 20 cm), and preliminary adhesion was performed by passing a press roll at 110 ° C. while extruding air between the glass plate and the film. The laminated body after the preliminary adhesion was allowed to stand at 135 ° C. and 1.2 MPa for 30 minutes in an autoclave to produce a laminated glass (20 sheets in total). The number of foreign matters in the laminated glass obtained using a magnifying glass was counted by visual observation. The total number of foreign substances in 20 laminated glasses was determined and evaluated according to the following criteria. The results are shown in Table 14.
A: 0 (pieces / 20 sheets)
B: 1 (20 pieces)
C: 2-3 (pieces / 20 sheets)
D: 4-8 (pieces / 20 pieces)
E: 9 or more (pieces / 20 sheets)

[Measurement of visible light transmittance and sunlight transmittance]
A laminated glass was produced in the same manner as in the above “undissolved part in the film”. Using a spectrophotometer “SolidSpec-3700” manufactured by Shimadzu Corporation, the transmittance in the wavelength region of 280 to 2500 nm was measured for the produced laminated glass. And according to JIS R3106, the visible light transmittance | permeability (%) of 380-780 nm was calculated | required. Moreover, the solar radiation transmittance (%) of 300-2500 nm was calculated | required using the weight value coefficient of JISR3106. The results are shown in Table 14.

[Colorability of film]
The laminated film obtained in “Preparation of laminated film” was heat-treated at 230 ° C., pressure 2 MPa, and 3 hours. The yellowness of the laminated film before the heat treatment and the laminated film after the heat treatment were measured, and the colorability was evaluated from the difference in yellowness (ΔYI) between the two according to the following criteria. The measurement was performed according to JIS K 7105 using an SM color computer “SM-TH” manufactured by Suga Test Instruments Co., Ltd. The results are shown in Table 14.
A: Less than 0.5 B: 0.5 or more and less than 1.0 C: 1.0 or more and less than 2.0 D: 2.0 or more and less than 3.0 E: 3.0 or more

[Production of single-layer film using recovered material]
The laminated film obtained in the above “production of laminated film” was cut into a size of 1 cm × 1 cm. With respect to 100 parts by mass of the cut laminated film, 70 parts by mass of unused PVB-1 powder and as a plasticizer, castor oil (glycerin tricarboxylic acid ester, 86% by mass of the carboxylic acid ester part is ricinoleic acid 13 mass% is any one of palmitic acid ester, stearic acid ester, oleic acid ester, linoleic acid ester, and linolenic acid ester, and 1 mass% is composed of other carboxylic acid esters; hydroxyl groups per molecule 2.6 number, hydroxyl value 160 mgKOH / g, number average molecular weight based on hydroxyl value 910) at a ratio of 30 parts by mass using a lab plast mill “C model” manufactured by Toyo Seiki Co., Ltd., 180 ° C., 50 rpm For 5 minutes. There was no fuming from the raw material mixture during melt kneading. The kneaded sample was hot-pressed (170 ° C., 30 minutes) to obtain a single-layer film having a size of 20 cm × 20 cm and a thickness of 760 μm.

[Colorability of single-layer film using recovered material]
The single layer film obtained in the above-mentioned “Preparation of Single Layer Film Using Collected Material” was heat-treated at 230 ° C., pressure 2 MPa, and 3 hours. The yellowness of the single-layer film before the heat treatment and the single film after the heat treatment were measured, and the colorability was evaluated from the difference in yellowness (ΔYI) between the two according to the following criteria. The measurement was performed according to JIS K 7105 using an SM color computer “SM-TH” manufactured by Suga Test Instruments Co., Ltd. The results are shown in Table 14.
A: Less than 0.5 B: 0.5 or more and less than 1.0 C: 1.0 or more and less than 2.0 D: 2.0 or more and less than 3.0 E: 3.0 or more

[Haze of single layer film using recovered material]
A single laminated glass was produced from the monolayer film obtained in the above (Preparation of recovered and reused monolayer PVB film) in the same manner as above (undissolved part in the film). The obtained laminated glass was manufactured by Suga Test Instruments Co., Ltd., using a haze meter (HZ-1), and the haze of the laminated glass-1 was measured and evaluated according to the following evaluation criteria. The results are shown in Table 14.
A: Less than 0.5 B: 0.5 or more and less than 1.0 C: 1.0 or more and less than 2.0 D: 2.0 or more and less than 3.0 E: 3.0 or more

[Preparation of multilayer film using recovered material]
The laminated film obtained in the above “production of laminated film” was cut into a size of 1 cm × 1 cm. With respect to 100 parts by mass of the cut laminated film, 70 parts by mass of PVB-1 powder and, as a plasticizer, castor oil (glycerin tricarboxylic acid ester, 86% by mass of the carboxylic acid ester part being ricinoleic acid ester 13% by mass is any one of palmitic acid ester, stearic acid ester, oleic acid ester, linoleic acid ester, and linolenic acid ester, and 1% by mass is composed of other carboxylic acid ester; the number of hydroxyl groups per molecule is 2 .6, hydroxyl value 160 mgKOH / g, number average molecular weight based on hydroxyl value 910) 15 parts by mass, 1.1 parts by mass of the above-mentioned zinc antimonate methanol dispersion having a concentration of 60% by mass, the above-mentioned phosphate ester 0.17 A dispersion obtained by mixing 15 parts by weight of the above-mentioned castor oil and 10 parts by weight of the above-mentioned castor oil Using Seisakusho Laboplastomill "C Model", 180 ° C., for 5 minutes melt-kneaded at 50 rpm. There was no fuming from the raw material mixture during melt kneading. The kneaded sample was hot-pressed (170 ° C., 30 minutes) to obtain a single-layer PVB film having a size of 20 cm × 20 cm and a thickness of 120 μm. This was designated as a layer (Y ′). Layer (X) (320 μm) / Layer (Y ′) (120 μm) In the same manner as in “Production of laminated film” except that the obtained layer (Y ′) was used instead of the layer (Y). A laminated film consisting of / layer (X) (320 μm) was obtained.

[Haze of multilayer film using recovered material]
The haze of the multilayer film using the obtained recovered material was measured in the same manner as in “Haze of single-layer PVB film using recovered material”. The results are shown in Table 14.

[Measurement of visible light transmittance and sunshine transmittance of multilayer film using collected material]
The visible light transmittance and sunshine transmittance of the multilayer film using the collected material were measured in the same manner as in “Haze of single-layer PVB film using collected material”. The results are shown in Table 14.

[Colorability of multilayer film using recovered material]
By the same method as “haze of single layer PVB film using recovered material”, the colorability of the multilayer film using the recovered material was evaluated. The results are shown in Table 14.

Examples 2-5
Production of each film in the same manner as in Example 1 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 14, respectively. And the evaluation was carried out. The results are shown in Table 14.

Examples 6 and 7
The PVB used for the production of the layer (X) and the PVB added to the recovered material were changed to those shown in Table 14, respectively, and the plasticizer used for the production of the layer (X) and the layer (Y) was changed to dibutoxyethyl adipate. Except for this, each film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 14.

Example 8
Except for changing the PVB used for the production of the layer (X), the PVB used for the production of the layer (Y), and the PVB added to the recovered material to those shown in Table 14, each of the films was prepared in the same manner as in Example 1. Fabrication and evaluation were performed. The results are shown in Table 14.

Examples 9-11
Each film was produced and evaluated in the same manner as in Example 1 except that the plasticizer added to the recovered material was changed to those shown in Table 14, respectively. The results are shown in Table 14.

Example 12
Each film was prepared and evaluated in the same manner as in Example 1 except that a tin-doped indium oxide isopropanol dispersion ("ITO isopropanol dispersion" manufactured by Mitsubishi Materials Corporation) was used instead of the zinc antimonate methanol dispersion. . The results are shown in Table 14.

Comparative Examples 1-3, 5, 7-11
Production of each film in the same manner as in Example 1 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 14, respectively. And the evaluation was carried out. The results are shown in Table 14.

Comparative Examples 4 and 6
The PVB used for the production of the layer (X), the PVB used for the production of the layer (Y), and the PVB added to the recovered material are respectively changed to those shown in Table 14 and used for the production of the layer (X) and the layer (Y). Each film was produced and evaluated in the same manner as in Example 1 except that the plasticizer was changed to dibutoxyethyl adipate. The results are shown in Table 14.

Example 13
[Production of Layer (X)]
50 parts by mass of the synthesized PVB-1 powder, 19 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer, and 0.175 parts by mass of “Tinuvin 328” manufactured by Ciba Japan as an ultraviolet absorber Was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using a lab plast mill “C model” manufactured by Toyo Seiki Seisakusho Co., Ltd. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 310 μm.

[Preparation of layer (Y)]
A zinc antimonate methanol dispersion having a concentration of 60% by mass was prepared by pulverizing a ZnSb ₂ O ₆ anhydrous zinc antimonate methanol dispersion (“CX-Z693M-F” manufactured by Nissan Chemical Co., Ltd.) with a bead mill. . 1.62 parts by mass of the obtained dispersion, 0.24 parts by mass of “DISPERBYK-102” manufactured by BYK Chemie as phosphate ester, and 14.3 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer 25% by weight 0.10 of a dispersion obtained by the above, 14.4 parts by mass of triethylene glycol di-2-ethylhexanoate, a mixture of magnesium acetate and potassium acetate (mixing mass ratio: 2/1) Mass parts and 43 parts by mass of the synthesized PVB-16 powder were melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using the Laboplast mill. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 140 μm.

[Production of laminated film]
Layer (X) and layer (Y) are layered in the order of layer (X) / layer (Y) / layer (X), and pressed in a form of 760 μm under conditions of 135 ° C. and 10 kg / cm ^2. A laminated film consisting of (X) (310 μm) / layer (Y) (140 μm) / layer (X) (310 μm) was obtained.

  Evaluation of the obtained laminated film was evaluated in the same manner as in Example 1. Moreover, except having used the obtained laminated | multilayer film as a recovered material, it carried out similarly to Example 1, and produced the single layer and the multilayer film which used the recovered material, and evaluated each. The results are shown in Table 15.

Comparative Examples 12-17
Production of each film in the same manner as in Example 13 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 15, respectively. And the evaluation was carried out. The results are shown in Table 15.

Example 14
[Production of Layer (X)]
50 parts by mass of the synthesized PVB-1 powder, 19 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer, and 0.175 parts by mass of “Tinuvin 328” manufactured by Ciba Japan as an ultraviolet absorber Was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using a lab plast mill “C model” manufactured by Toyo Seiki Seisakusho Co., Ltd. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 300 μm.

[Preparation of layer (Y)]
A zinc antimonate methanol dispersion having a concentration of 60% by mass was prepared by pulverizing a ZnSb ₂ O ₆ anhydrous zinc antimonate methanol dispersion (“CX-Z693M-F” manufactured by Nissan Chemical Co., Ltd.) with a bead mill. . 1.62 parts by mass of the obtained dispersion, 0.24 parts by mass of “DISPERBYK-102” manufactured by Big Chemie as phosphate ester, and 21 parts by mass of triethylene glycol di-2-ethylhexanoate as a plasticizer were mixed. The obtained dispersion, 22 parts by mass of triethylene glycol-di-2-ethylhexanoate, 0.10 parts by mass of a 25% by mass aqueous solution of a mixture of magnesium acetate and potassium acetate (mixing mass ratio: 2/1), and 43 parts by mass of the synthesized PVB-17 powder was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using the Laboplast mill. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 160 μm.

[Production of laminated film]
Layer (X) and layer (Y) are layered in the order of layer (X) / layer (Y) / layer (X), and pressed in a form of 760 μm under conditions of 135 ° C. and 10 kg / cm ^2. A laminated film consisting of (X) (300 μm) / layer (Y) (160 μm) / layer (X) (300 μm) was obtained.

  Evaluation of the obtained laminated film was evaluated in the same manner as in Example 1. Further, the recovered material was used in the same manner as in Example 1 except that the obtained laminated film was used as a recovered material, and the amount of PVB to be newly added and the amount of plasticizer were changed as shown in Table 16. A monolayer film and a multi-layer film were prepared and evaluated. The results are shown in Table 16.

Comparative Examples 18-23
Production of each film in the same manner as in Example 14 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 16, respectively. And the evaluation was carried out. The results are shown in Table 16.

Example 15
[Production of Layer (X)]
46 parts by mass of the synthesized PVB-9 powder, 23 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer, and 0.175 parts by mass of “Tinuvin 328” manufactured by Ciba Japan as an ultraviolet absorber Was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using a lab plast mill “C model” manufactured by Toyo Seiki Seisakusho Co., Ltd. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 320 μm.

[Preparation of layer (Y)]
A zinc antimonate methanol dispersion having a concentration of 60% by mass was prepared by pulverizing a ZnSb ₂ O ₆ anhydrous zinc antimonate methanol dispersion (“CX-Z693M-F” manufactured by Nissan Chemical Co., Ltd.) with a bead mill. . 1.62 parts by mass of the obtained dispersion, 0.24 parts by mass of “DISPERBYK-102” manufactured by BYK Chemie as phosphate ester, and 14.3 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer 25% by weight 0.10 of a dispersion obtained by the above, 14.4 parts by mass of triethylene glycol di-2-ethylhexanoate, a mixture of magnesium acetate and potassium acetate (mixing mass ratio: 2/1) Mass parts and 43 parts by mass of the synthesized PVB-16 powder were melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using the Laboplast mill. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 120 μm.

[Production of laminated film]
Layer (X) and layer (Y) are layered in the order of layer (X) / layer (Y) / layer (X), and pressed in a form of 760 μm under conditions of 135 ° C. and 10 kg / cm ^2. A laminated film consisting of (X) (320 μm) / layer (Y) (120 μm) / layer (X) (320 μm) was obtained.

  Evaluation of the obtained laminated film was evaluated in the same manner as in Example 1. Moreover, it was carried out similarly to Example 1 except having used the obtained laminated | multilayer film as a collection | recovery thing, and having changed the kind and quantity of PVB to add newly, and the quantity of a plasticizer as shown in Table 17. A monolayer film and a multilayer film using the recovered material were prepared and evaluated. The results are shown in Table 17.

Comparative Examples 24-29
Production of each film in the same manner as in Example 15 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 17, respectively. And the evaluation was carried out. The results are shown in Table 17.

Example 16
[Production of Layer (X)]
46 parts by mass of the synthesized PVB-9 powder, 23 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer, and 0.175 parts by mass of “Tinuvin 328” manufactured by Ciba Japan as an ultraviolet absorber Was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using a lab plast mill “C model” manufactured by Toyo Seiki Seisakusho Co., Ltd. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 310 μm.

[Preparation of layer (Y)]
A zinc antimonate methanol dispersion having a concentration of 60% by mass was prepared by pulverizing a ZnSb ₂ O ₆ anhydrous zinc antimonate methanol dispersion (“CX-Z693M-F” manufactured by Nissan Chemical Co., Ltd.) with a bead mill. . 1.62 parts by mass of the obtained dispersion, 0.24 parts by mass of “DISPERBYK-102” manufactured by Big Chemie as phosphate ester, and 21 parts by mass of triethylene glycol di-2-ethylhexanoate as a plasticizer were mixed. The obtained dispersion, 21 parts by mass of triethylene glycol-di-2-ethylhexanoate, 0.10 parts by mass of a 25% by mass aqueous solution of a mixture of magnesium acetate and potassium acetate (mixing mass ratio: 2/1), and 43 parts by mass of the synthesized PVB-17 powder was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using the Laboplast mill. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 140 μm.

[Production of laminated film]
Layer (X) and layer (Y) are layered in the order of layer (X) / layer (Y) / layer (X), and pressed in a form of 760 μm under conditions of 135 ° C. and 10 kg / cm ^2. A laminated film consisting of (X) (310 μm) / layer (Y) (140 μm) / layer (X) (310 μm) was obtained.

  Evaluation of the obtained laminated film was evaluated in the same manner as in Example 1. Moreover, it was carried out similarly to Example 1 except having used the obtained laminated | multilayer film as collection | recovery, and having changed the kind and quantity of PVB to add newly, and the quantity of a plasticizer as shown in Table 18. A monolayer film and a multilayer film using the recovered material were prepared and evaluated. The results are shown in Table 18.

Comparative Examples 30-35
Production of each film in the same manner as in Example 16 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 18, respectively. And the evaluation was carried out. The results are shown in Table 18.

Example 17
[Production of Layer (X)]
40.6 parts by mass of the synthesized PVB-10 powder, 28.4 parts by mass of triethylene glycol-di-2-ethylhexanoate as a plasticizer, and “Tinuvin 328” manufactured by Ciba Japan as an ultraviolet absorber are set to 0.000. 175 parts by mass was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using a lab plast mill “C model” manufactured by Toyo Seiki Co., Ltd. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 320 μm.

[Preparation of layer (Y)]
A zinc antimonate methanol dispersion having a concentration of 60% by mass was prepared by pulverizing a ZnSb ₂ O ₆ anhydrous zinc antimonate methanol dispersion (“CX-Z693M-F” manufactured by Nissan Chemical Co., Ltd.) with a bead mill. . 1.62 parts by mass of the obtained dispersion, 0.24 parts by mass of “DISPERBYK-102” manufactured by Big Chemie as phosphate ester, and 21 parts by mass of triethylene glycol di-2-ethylhexanoate as a plasticizer were mixed. The obtained dispersion, 21 parts by mass of triethylene glycol-di-2-ethylhexanoate, 0.10 parts by mass of a 25% by mass aqueous solution of a mixture of magnesium acetate and potassium acetate (mixing mass ratio: 2/1), and 43 parts by mass of the synthesized PVB-17 powder was melt-kneaded for 5 minutes at 170 ° C. and 50 rpm using the Laboplast mill. During melt kneading, nitrogen (100 mL / min) was continuously blown into the container. The obtained kneaded material was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film having a thickness of 120 μm.

[Production of laminated film]
Layer (X) and layer (Y) are layered in the order of layer (X) / layer (Y) / layer (X), and pressed in a form of 760 μm under conditions of 135 ° C. and 10 kg / cm ^2. A laminated film consisting of (X) (320 μm) / layer (Y) (120 μm) / layer (X) (320 μm) was obtained.

  Evaluation of the obtained laminated film was evaluated in the same manner as in Example 1. Moreover, it was carried out similarly to Example 1 except having used the obtained laminated | multilayer film as a collection | recovery, and having changed the kind and quantity of PVB to add newly, and the quantity of a plasticizer as shown in Table 19. A monolayer film and a multilayer film using the recovered material were prepared and evaluated. The results are shown in Table 19.

Comparative Examples 36-41
Production of each film in the same manner as in Example 17 except that PVB used for production of layer (X), PVB used for production of layer (Y), and PVB added to the recovered material were changed to those shown in Table 19, respectively. And the evaluation was carried out. The results are shown in Table 19.

  In the said Example, the multilayer film of this invention has sufficient heat-insulating property, it is shown that there is little coloring by heating and there are few foreign materials (undissolved part). And the film using the collection | recovery of the said multilayer film is also shown that there is little coloring, there are few foreign materials (undissolved part), and it has the outstanding transparency.

Claims (8)

A layer containing polyvinyl acetal (I) having an acetalization degree of 55 to 80 mol% and a vinyl ester monomer unit content of 0.1 to 1.5 mol%, an ultraviolet absorber, and a plasticizer ( X) and
Polyvinyl acetal (II) having a degree of acetalization of 70 to 85 mol% and a vinyl ester monomer unit content of 5 to 15 mol%, heat ray shielding fine particles, surfactant, alkali metal salt and / or alkaline earth A metal salt, and a layer (Y) containing a plasticizer,
Layer (X) is disposed on both outer sides of layer (Y),
A multilayer film in which both polyvinyl acetal (I) and polyvinyl acetal (II) satisfy the following formulas (1) and (2).
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)
Where
A: Peak top molecular weight B measured by a differential refractive index detector when polyvinyl acetal (I) or polyvinyl acetal (II) heated at 230 ° C. for 3 hours is measured by gel permeation chromatography: 3 at 230 ° C. Peak top molecular weight b: peak top molecular weight (B) measured with an absorptiometric detector (measuring wavelength 280 nm) when the time-heated polyvinyl acetal (I) or polyvinyl acetal (II) is measured by gel permeation chromatography The absorbance at. The multilayer film according to claim 1, wherein both the polyvinyl acetal (I) and the polyvinyl acetal (II) satisfy the following formulas (3) and (4).
(AC) / A <0.65 (3)
0.35 × 10 ⁻³ ≦ c ≦ 4.50 × 10 ⁻³ (4)
Where
A: Same as the above formula (1) C: Absorbance detector (measurement wavelength: 320 nm) when measured by gel permeation chromatography of polyvinyl acetal (I) or polyvinyl acetal (II) heated at 230 ° C. for 3 hours The peak top molecular weight c measured in (1) is the absorbance at the peak top molecular weight (C).   The multilayer film according to claim 1 or 2, wherein the polyvinyl acetal (I) and the polyvinyl acetal (II) are polyvinyl butyral.   The intermediate film for laminated glasses which consists of a multilayer film in any one of Claims 1-3.   Laminated glass formed by bonding a plurality of glass plates using the interlayer film for laminated glass according to claim 4.   The manufacturing method of the monolayer film which forms into a film, after melt-kneading the recovered material of the multilayer film in any one of Claims 1-3. Polyvinyl acetal having a degree of acetalization of 55 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 15 mol%, and satisfying the following formulas (1) and (2): The method for producing a single layer film according to claim 6, wherein (III) and a plasticizer are melt-kneaded and then formed into a film.
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)
Where
A: Peak top molecular weight measured by a differential refractive index detector when polyvinyl acetal (III) heated at 230 ° C. for 3 hours was measured by gel permeation chromatography B: Polyvinyl acetal heated at 230 ° C. for 3 hours Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when (III) is subjected to gel permeation chromatography measurement: absorbance at peak top molecular weight (B). The recovered material of the multilayer film according to any one of claims 1 to 3, the degree of acetalization is 55 to 85 mol%, and the content of the vinyl ester monomer unit is 0.1 to 15 mol%, The film is formed by melt-kneading polyvinyl acetal (III) satisfying the following formulas (1) and (2), a plasticizer, a heat ray shielding fine particle, a surfactant, and an alkali metal salt and / or alkaline earth metal salt. On both outer sides of the layer (Y ')
Layer (X) formed by melt-kneading polyvinyl acetal (I), ultraviolet absorber, and plasticizer
The manufacturing method of the multilayer film which arrange | positions.
(AB) / A <0.60 (1)
0.50 × 10 ⁻³ ≦ b ≦ 1.00 × 10 ⁻² (2)
Where
A: Peak top molecular weight measured by a differential refractive index detector when polyvinyl acetal (III) heated at 230 ° C. for 3 hours was measured by gel permeation chromatography B: Polyvinyl acetal heated at 230 ° C. for 3 hours Peak top molecular weight b measured with an absorptiometric detector (measurement wavelength 280 nm) when (III) is subjected to gel permeation chromatography measurement: absorbance at peak top molecular weight (B).

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