WO2015019445A1

WO2015019445A1 - Film comprising polyvinyl acetal

Info

Publication number: WO2015019445A1
Application number: PCT/JP2013/071363
Authority: WO
Inventors: 楠藤　健; 芳聡浅沼; 俊輔藤岡; 辻　嘉久
Original assignee: 株式会社クラレ
Priority date: 2013-08-07
Filing date: 2013-08-07
Publication date: 2015-02-12
Also published as: JP5420804B1; JPWO2015019445A1

Abstract

A film comprising polyvinyl acetal which has a degree of acetalization of 50 to 85 mol%, a vinyl ester monomer unit of 0.1 to 20 mol%, and a viscosity-average polymerization degree of 1400 to 5000, wherein the film satisfies formulae (1) and (2). (A-B)/A<0.80 (1) 1.00×10^-2<(b/y)/(a/x)<2.00×10^-1 (2) Accordingly, a film which has lower coloring due to heat and less foreign matters (undissolved fractions) is provided. Also provided is a laminated glass in which the film is used as an interlayer and which has excellent penetration resistance.

Description

Film containing polyvinyl acetal

The present invention relates to a film containing polyvinyl acetal. The present invention also relates to an interlayer film for laminated glass comprising the film, and a laminated glass using the interlayer 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, as conventional problems, 1) polyvinyl acetal film is easily colored by heating, 2) foreign matter (undissolved part) is likely to be generated in polyvinyl acetal film, and 3) polyvinyl acetal film is a safety laminated glass. When used, there was a problem that penetration resistance was liable to decrease. Various proposals have been made to solve these problems. For example,

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, in the case of the methods described in Patent Documents 1 to 3, foreign matter was likely to be generated in the film produced using the obtained polyvinyl acetal. Furthermore, when the film was used for safety laminated glass, the penetration resistance was liable to decrease. For these reasons, there is a strong demand for films made of polyvinyl acetal in which all the above-mentioned problems are solved.

JP 2011-219670 A JP 2011-219671 A Japanese Patent Laid-Open No. 05-140211

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a film containing polyvinyl acetal that is less colored by heating and less foreign matter (undissolved content). Furthermore, when a film obtained by repeatedly heating a film containing polyvinyl acetal is used as an interlayer film for laminated glass, the laminated glass has excellent penetration resistance of laminated glass, and is particularly suitable for use in safety laminated glass for automobiles. It is an object to provide an intermediate film for use.

The above problem is a film containing polyvinyl acetal having an acetalization degree of 50 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 20 mol%, and a viscosity average polymerization degree of 1400 to 5000. This is solved by providing a film satisfying the following formulas (1) and (2).
(AB) / A <0.80 (1)
1.00 × 10 ⁻² <(b / y) / (a / x) <2.00 × 10 ⁻¹ (2)

Where
A: Peak top molecular weight a of a polymer component measured by a differential refractive index detector when the film heated at 230 ° C. for 3 hours was measured by gel permeation chromatography (hereinafter sometimes abbreviated as GPC) : Signal intensity B at peak top molecular weight (A): Peak top molecular weight b of polymer component measured by an absorptiometric detector (measurement wavelength 280 nm) when GPC measurement is performed on the film heated at 230 ° C. for 3 hours: Signal intensity x at peak top molecular weight (B): Measured with a differential refractive index detector when GPC measurement is performed on monodisperse polymethyl methacrylate (hereinafter, polymethyl methacrylate may be abbreviated as PMMA). Signal intensity at peak top molecular weight y: GPC is the monodispersed PMMA When I was boss, a signal intensity at the peak top molecular weight measured by spectrophotometric detector (measuring wavelength 220 nm).

However, in GPC measurement of film and PMMA,
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 temperature: 40 ° C
Flow rate: 1.0 ml / min.

It is preferable that the film satisfies the following formulas (3) and (4).
(AC) / A <0.80 (3)
5.00 × 10 ⁻³ <(c / y) / (a / x) <7.00 × 10 ⁻² (4)

Where
A: a, x, y the same as the above formula (1) C: the same as the above formula (2) C: absorptiometric detector (measurement wavelength: 320 nm) when the film heated at 230 ° C. for 3 hours is measured by GPC The peak top molecular weight c of the polymer component measured in (1) is the signal intensity at the peak top molecular weight (C).

The polyvinyl acetal is preferably polyvinyl butyral (hereinafter sometimes abbreviated as PVB).

It is preferable that the film further contains a plasticizer. At this time, it is more preferable that the film contains triethylene glycol-di-2-ethylhexanoate as a plasticizer.

The above-described problems are obtained by acetalizing polyvinyl alcohol so that the degree of acetalization is 50 to 85 mol%, the content of vinyl ester monomer units is 0.1 to 20 mol%, and the viscosity average degree of polymerization is 1400 to 5000. The problem can also be solved by providing a method for producing the film by melt-molding the polyvinyl acetal after obtaining the acetal.

An interlayer film for laminated glass made of the 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.

The film of the present invention is less colored by heating and has less foreign matter (undissolved content). Moreover, the laminated glass using the film obtained by repeatedly heating the film as an intermediate film has excellent penetration resistance. Therefore, the film is useful as an interlayer film for laminated glass, in particular, a safety laminated glass interlayer film for automobiles.

In the film of Example 1, the relationship between the molecular weight and the value measured by the differential refractive index detector (RI), and the relationship between the molecular weight and the absorbance measured by the absorbance detector (UV) (measurement wavelength 280 nm). It is the shown graph. In PVA-1, the relationship between the molecular weight and the value measured by the differential refractive index detector (RI), and the relationship between the molecular weight and the absorbance measured by the absorbance detector (UV) (measurement wavelength 280 nm) were shown. It is a graph. In PVB-1, the relationship between the molecular weight and the value measured by the differential refractive index detector (RI), and the relationship between the molecular weight and the absorbance measured by the absorptiometric detector (UV) (measurement wavelength 280 nm) were shown. It is a graph.

The film of the present invention is a film containing polyvinyl acetal having an acetalization degree of 50 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 20 mol%, and a viscosity average polymerization degree of 1400 to 5000. Therefore, the following expressions (1) and (2) are satisfied.
(AB) / A <0.80 (1)
1.00 × 10 ⁻² <(b / y) / (a / x) <2.00 × 10 ⁻¹ (2)

Where
A: When the film heated at 230 ° C. for 3 hours is subjected to GPC measurement, the peak top molecular weight of the polymer component measured by the differential refractive index detector a: the signal intensity at the peak top molecular weight (A) B: at 230 ° C. When the film heated for 3 hours is measured by GPC, the peak intensity of the polymer component measured by an absorptiometer (measurement wavelength: 280 nm) b: signal intensity at peak top molecular weight (B) x: monodisperse poly Signal intensity at peak top molecular weight measured with a differential refractive index detector when GPC measurement is performed on methyl methacrylate y: Absorbance detector (measurement wavelength 220 nm when GPC measurement is performed on the monodispersed polymethyl methacrylate) ) Is the signal intensity at the peak top molecular weight measured in (1).

However, in GPC measurement of film and PMMA,
Mobile phase: HFIP containing 20 mmol / l sodium trifluoroacetate
Sample concentration: 1.00 mg / ml (solvent: 20 mmol / l HFIP containing sodium trifluoroacetate)
Sample injection volume: 100 μl
Column temperature: 40 ° C
Flow rate: 1.0 ml / min.

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 cell of the detection part of the absorptiometric detector preferably has a cell length (optical path length) of 10 mm. 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 film 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 concentration (g / l) of the film component. On the other hand, the components detected by the absorptiometric detector are only those having a structure that absorbs a predetermined wavelength. By the GPC measurement, the concentration and absorbance at a predetermined wavelength can be measured for each molecular weight component of the film.

HFIP containing sodium trifluoroacetate having a concentration of 20 mmol / l is used as the solvent and mobile phase used for dissolving the film and PMMA measured in the GPC measurement. HFIP can dissolve the film and PMMA of the present invention. Further, by adding sodium trifluoroacetate, adsorption of film components and PMMA to the column filler is prevented. The flow rate and column temperature in the GPC measurement are appropriately adjusted according to the type of column used. The flow rate in the GPC measurement is usually 1.0 ml / min, and the column temperature is usually 40 ° C.

The GPC column used in the GPC measurement is not particularly limited as long as the components in the film of the present invention can be separated for each molecular weight. Specifically, “GPC HFIP-806M” manufactured by Showa Denko KK is preferably used.

In the present invention, standard PMMA is monodispersed PMMA. As the standard PMMA, monodispersed PMMA, which is usually used as a standard for preparing a calibration curve for molecular weight measurement by GPC measurement, can be used. 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 prepared using the detector is used for the measurement with the differential refractive index detector, and a calibration prepared using the detector (measurement wavelength: 220 nm) for the measurement with the absorptiometric detector. Use lines. Using these calibration curves, the GPC elution volume is converted into the molecular weight, and the peak top molecular weight (A) and the peak top molecular weight (B) are determined.

The film is heated at 230 ° C. for 3 hours before the GPC measurement. In the present invention, the film is heated by the following method. The film is heated by hot pressing for 3 hours at a pressure of 2 MPa and 230 ° C. Thereby, the difference in the hue of the sample after the heat treatment is clearly reflected in the difference in the absorbance (that is, the signal intensity detected by the absorptiometric detector). The thickness of the film to be heated is 600 to 800 μm, preferably about 760 μm, which is the thickness of a normal laminated glass interlayer.

A measurement sample is obtained by dissolving the heated film in the above-described solvent (HFIP containing sodium trifluoroacetate). The concentration of 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 in the film exceeds 2400, the excluded volume increases, and therefore the measurement sample concentration may not be measured with good reproducibility at 1.00 mg / ml. In that case, an appropriately diluted sample (injection amount 100 μl) is used. The signal intensity detected by the absorptiometric detector and the differential refractive index detector is proportional to the concentration of the sample. Therefore, the concentration of the diluted sample and the actually measured signal intensity are used to convert each signal intensity when the concentration of the measurement sample is 1.00 mg / ml.

FIG. 1 shows the relationship between the molecular weight and the signal intensity measured by the differential refractive index detector, and the molecular weight and the absorptiometric detector (measurement wavelength) obtained by GPC measurement of the film of the present invention. It is the graph which showed the relationship with the signal intensity | strength (absorbance) measured by 280 nm. 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 signal intensity measured by the differential refractive index detector against the molecular weight (horizontal axis) of the film component converted from the elution volume. The peak seen in the chromatogram near the molecular weight of 100,000 is the peak of the polymer component. In the present invention, the molecular weight at the peak position of such a polymer component is defined as the peak top molecular weight (A) of the polymer component, and the signal intensity at the peak top molecular weight (A) is defined as the signal intensity (a). Since the film of the present invention contains polyvinyl acetal having a viscosity average degree of polymerization of 1400 to 5000, the peak top molecular weight (A) of the polymer component usually exceeds 3500. In addition, in FIG. 1, the peak seen in the molecular weight 1500 vicinity is a peak of the plasticizer contained in a film. When there are a plurality of peaks having a peak top molecular weight exceeding 3500 in the chromatogram, the molecular weight at the peak position having the highest peak height is defined as the peak top molecular weight (A).

In FIG. 1, the chromatogram indicated by “UV” shows the signal intensity (absorbance) measured with an absorptiometric detector (measurement wavelength 280 nm) with respect to the molecular weight (horizontal axis) of the film component converted from the elution volume. It is a plot. The peak seen in the chromatogram near the molecular weight of 50,000 is the peak of the polymer component. In the present invention, the molecular weight at the peak position of such a polymer component is defined as the peak top molecular weight (B) of the polymer component, and the signal intensity (absorbance) at the peak top molecular weight (B) is defined as the signal intensity (b). Since the film of the present invention contains polyvinyl acetal having a viscosity average polymerization degree of 1400 to 5000, the peak top molecular weight (B) of the polymer component usually exceeds 3500. When there are a plurality of peaks having a peak top molecular weight exceeding 3500 in the chromatogram, the molecular weight at the peak position having the highest peak height is defined as the peak top molecular weight (B).

The film of the present invention is measured by a peak top molecular weight (A) of a polymer component measured by a differential refractive index detector and a spectrophotometric detector (measurement wavelength: 280 nm) when GPC is measured by the above-described method. The peak top molecular weight (B) of the polymer component satisfies the following formula (1).
(AB) / A <0.80 (1)

The peak top molecular weight (A) is a value that serves as an index of the molecular weight of the polymer component in the film. On the other hand, the peak top molecular weight (B) is derived from a component having absorption at 280 nm, which is present in the polymer component. Usually, since the peak top molecular weight (A) is larger than the peak top molecular weight (B), (AB) / A becomes a positive value. As the peak top molecular weight (B) increases, (AB) / A decreases, and as the peak top molecular weight (B) decreases, (AB) / A increases. That is, when (AB) / A is large, it means that the low molecular weight component in the polymer component contains many components that absorb ultraviolet light having a wavelength of 280 nm.

When (AB) / A is 0.80 or more, as described above, the low molecular weight component contains more components that absorb ultraviolet light having a wavelength of 280 nm. In this case, foreign matter in the film increases. Moreover, the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. (AB) / A is preferably less than 0.75, more preferably less than 0.70.

The film of the present invention satisfies the following formula (2).
1.00 × 10 ⁻² <(b / y) / (a / x) <2.00 × 10 ⁻¹ (2)

In the formula (2), a is the signal intensity measured by the differential refractive index detector at the peak top molecular weight (A) in the GPC measurement. b is the signal intensity (absorbance) measured with an absorptiometric detector (measurement wavelength 280 nm) at the peak top molecular weight (B).

In the formula (2), x is the signal intensity at the peak top molecular weight measured by the differential refractive index detector when monodispersed PMMA is measured by GPC. y is the signal intensity (absorbance) at the peak top molecular weight measured with an absorptiometer (measurement wavelength 220 nm) when the monodispersed PMMA is measured by GPC. The GPC measurement of monodisperse PMMA is the same as the GPC measurement of the film described above except that monodisperse PMMA is used instead of the heated film and the measurement wavelength of the absorptiometer is changed to 220 nm. Do. The signal intensity (x) is obtained in the same manner as the signal intensity (a). The signal intensity (y) is obtained in the same manner as the signal intensity (b). As the monodispersed PMMA used for obtaining x and y, PMMA having a weight average molecular weight of about 85,000 is preferable.

(B / y) / (a / x) is an index of the content of a component having a structure that absorbs ultraviolet light having a wavelength of 280 nm in the polymer component of the film. When this value is large, it means that the content is large. As described above, the signal intensity by the differential refractive index detector is approximately proportional to the concentration (g / l) of the film component. On the other hand, what is detected by the absorptiometric detector is only the component having absorption at 280 nm which is the measurement wavelength, and the signal intensity (absorbance) by the absorptiometric detector is proportional to the concentration of the component having absorption at 280 nm. . Usually, the signal intensity of the differential refractive index detector is indicated by “millivolt”, and the signal intensity (absorbance) of the absorptiometric detector is indicated by “absorbance unit (AU)”.

However, since the signal intensity (a) measured by the differential refractive index detector and the signal intensity (b) obtained by the absorptiometric detector differ depending on the model of the GPC apparatus and the measurement conditions, the ratio of both is simply compared. It ’s difficult. On the other hand, in the present invention, as described below, the ratio of the signal intensity obtained by the differential refractive index detector and the signal intensity obtained by the absorptiometric detector is not different depending on the model of the GPC apparatus and the measurement conditions. Desired.

In the present invention, the ratio (a / x) of the film signal intensity (a) by the differential refractive index detector to the signal intensity (x) of monodisperse PMMA by the differential refractive index detector, and the monodispersion by the absorptiometric detector And the ratio (b / y) of the signal intensity (b) of the film by the absorptiometric detector to the signal intensity (y) of PMMA. And ratio (b / y) / (a / x) of both is calculated | required and this is made into the parameter | index of content of the component which has a structure which absorbs ultraviolet light with a wavelength of 280 nm. Thus, by using the signal intensity of monodispersed PMMA as a reference, the same index can be used for evaluation regardless of the device model and measurement conditions.

The film of the present invention preferably satisfies the following formula (2 ′), and more preferably satisfies the following formula (2 ″).
1.50 × 10 ⁻² <(b / y) / (a / x) <1.50 × 10 ⁻¹ (2 ′)
2.00 × 10 ⁻² <(b / y) / (a / x) <1.00 × 10 ⁻¹ (2 ″)

When (b / y) / (a / x) is 1.00 × 10 ⁻² or less, as described above, there are few components that absorb ultraviolet light having a wavelength of 280 nm in the polymer component of the film. Therefore, foreign matter (undissolved part) in the film increases. Moreover, the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. Conversely, when (b / y) / (a / x) is 2.00 × 10 ⁻¹ or more, the polymer component of the film has many components that absorb ultraviolet light having a wavelength of 280 nm. Therefore, the coloring resistance of a film and the penetration resistance of the obtained laminated glass deteriorate.

Measured with a differential refractive index detector in the GPC measurement from the viewpoint of excellent balance of performance regarding color resistance of the film, foreign matter in the film (undissolved content) and penetration resistance of the laminated glass obtained using the film. The peak top molecular weight (A) and the peak top molecular weight (C) measured with an absorptiometric detector (measurement wavelength 320 nm) are expressed by the following formula (3).
(AC) / A <0.80 (3)
It is preferable to satisfy.

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. The peak top molecular weight (C) is derived from the component having an absorption at 320 nm, which is present in the polymer component in the film. Usually, since the peak top molecular weight (A) is larger than the peak top molecular weight (C), (AC) / A becomes a positive value. As the peak top molecular weight (C) increases, (AC) / A decreases, and as the peak top molecular weight (C) decreases, (AC) / A increases. That is, when (AC) / A is large, it means that the low molecular weight component in the polymer component contains many components that absorb ultraviolet light having a wavelength of 320 nm.

When (AC) / A is 0.80 or more, as described above, the low molecular weight component contains more components that absorb ultraviolet rays having a wavelength of 320 nm. In this case, foreign matter in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. (AC) / A is more preferably less than 0.75, and even more preferably less than 0.70.

The film of the present invention preferably satisfies the following formula (4).
5.00 × 10 ⁻³ <(c / y) / (a / x) <7.00 × 10 ⁻² (4)

In the formula (4), a, x and y are the same as the above formula (2). c is the signal intensity (absorbance) measured with an absorptiometric detector (measurement wavelength: 320 nm) at the peak top molecular weight (C).

Here, (c / y) / (a / x) is an index of the content of a component having a structure that absorbs ultraviolet light having a wavelength of 320 nm in the polymer component of the film. When this value is large, it means that the content is large. And it calculates | requires similarly to the above-mentioned (b / y) / (a / x) except the measurement wavelength in an absorptiometric detector being 320 nm.

The film of the present invention preferably satisfies the following formula (4 ′), and more preferably satisfies the following formula (4 ″).
7.00 × 10 ⁻³ <(c / y) / (a / x) <6.00 × 10 ⁻² (4 ′)
^{1.00 × 10 -2 <(c /} y) / (a / x) <5.00 × 10 -2 (4 ")

When (c / y) / (a / x) is 5.00 × 10 ⁻³ or less, as described above, the polymer component of the film has few components that absorb ultraviolet light having a wavelength of 320 nm. Therefore, there is a possibility that foreign matter in the film increases. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. Conversely, when (c / y) / (a / x) is 7.00 × 10 ⁻² or more, the polymer component of the film has many components that absorb ultraviolet light having a wavelength of 320 nm. Therefore, there exists a possibility that the coloring resistance of a film and the penetration resistance of the laminated glass obtained may deteriorate.

The degree of acetalization of the polyvinyl acetal in the film of the present invention is 50 to 85 mol%. The degree of acetalization is preferably 55 to 82 mol%, more preferably 60 to 78 mol%, still more preferably 65 to 75 mol%. When the degree of acetalization is less than 50 mol%, the compatibility with a plasticizer or the like decreases. Moreover, the penetration resistance of the obtained laminated glass falls. On the other hand, when the degree of acetalization exceeds 85 mol%, the efficiency of the acetalization reaction is remarkably reduced, and therefore it is necessary to carry out the reaction at a high temperature for a long time. As a result, the penetration resistance of the obtained laminated glass is lowered, and the coloring resistance of the obtained film is lowered.

The degree of acetalization represents the ratio of the acetalized vinyl alcohol monomer unit to the total monomer units constituting the polyvinyl acetal. Among the vinyl alcohol monomer units in the raw material polyvinyl alcohol, those not acetalized remain as vinyl alcohol monomer units in the obtained polyvinyl acetal.

The viscosity average polymerization degree of the polyvinyl acetal is represented by the viscosity average polymerization degree of the starting polyvinyl alcohol measured according to JIS-K6726. That is, after re-saponifying polyvinyl alcohol to a saponification degree of 99.5 mol% or more and purifying it, 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 polyvinyl alcohol 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)}

The viscosity average polymerization degree of the polyvinyl acetal is 1400 to 5000, and preferably 1500 to 3500. When the viscosity average degree of polymerization is less than 1400, the film strength is low, and the resulting laminated glass has insufficient penetration resistance. On the other hand, when the polymerization degree exceeds 5000, the melt viscosity becomes too high and film formation becomes difficult.

The content of the vinyl ester monomer unit in the polyvinyl acetal is 0.1 to 20 mol%, preferably 0.3 to 18 mol%, more preferably 0.5 to 15 mol%, Preferably, it is 0.7 to 13 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. On the other hand, when the content of the vinyl ester monomer unit exceeds 20 mol%, the film becomes intensely colored.

The content of monomer units other than acetalized monomer units, vinyl ester monomer units and vinyl alcohol monomer units in the polyvinyl acetal is preferably 20 mol% or less, more preferably 10%. It is less than mol%.

The polyvinyl acetal is usually produced by acetalizing polyvinyl alcohol.

The saponification degree of the raw material PVA used for the production of polyvinyl acetal is preferably 80 to 99.9 mol%, more preferably 82 to 99.7 mol%, still more preferably 85 to 99.5 mol%, Preferably, it is 87 to 99.3 mol%. When the saponification degree of raw material PVA is less than 80 mol%, there is a possibility that the number of foreign matters (undissolved part) in the film may increase or the coloring resistance of the film may be lowered. When the saponification degree exceeds 99.9 mol%, there is a possibility that PVA cannot be stably produced.

The raw material PVA may contain an alkali metal salt of carboxylic acid, and its content is preferably 0.50% by mass or less, more preferably 0.37% by mass or less, and 0.28% by mass in terms of the mass of the alkali metal. % Or less is more preferable, and 0.23 mass or less is particularly preferable. When the content of the alkali metal salt of the carboxylic acid in the raw material PVA exceeds 0.50% by mass, the film 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 vinyl ester monomers used in 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 versatic. Examples thereof include vinyl acid, and vinyl acetate is particularly preferable.

The raw material PVA can also be produced by polymerizing vinyl ester monomers in the presence of thiol compounds 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 in the polymerization reaction include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl-valeronitrile), 2,2′-azobis (4-methoxy). Azo initiators such as -2,4-dimethylvaleronitrile); organic peroxide initiators such as benzoyl peroxide, n-propyl peroxycarbonate, peroxydicarbonate, etc., within a range that does not impair the effects of the present invention. A well-known initiator is mentioned. Among them, an organic oxide initiator having a half-life of 10 to 110 minutes at 60 ° C. is preferable, and peroxydicarbonate is particularly preferable. There is no particular limitation on the polymerization temperature for carrying out the polymerization reaction, but a range of 5 ° C to 200 ° C 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, 1-hexene; carboxylic acids such as fumaric acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, or the like Derivatives; acrylic acid or salts thereof; acrylic acid 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; Derivatives of methacrylamide such as methacrylamide, N-methylmethacrylamide and N-ethylmethacrylamide Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, and n-butyl vinyl ether; vinyl group-containing vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, and 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 a sulfonic acid group such as phonic 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 a vinyl trimethoxysilane, vinylmethyldimethoxysilane, Monomers having a silyl group such as xylsilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, 3- (meth) acrylamide-propyltrimethoxysilane, 3- (meth) acrylamide-propyltriethoxysilane Etc. The amount of the monomer that can be copolymerized with these vinyl ester monomers varies depending on the purpose and use of the monomer, but is usually based on all monomers used for copolymerization. Is 20 mol% or less, preferably 10 mol% or less.

PVA is obtained by saponifying the polyvinyl ester obtained by the above method in an alcohol solvent.

As the catalyst for the saponification reaction of polyvinyl ester, an alkaline substance is usually used, and 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. 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 during the saponification reaction.

Examples of the solvent that can be used for the saponification reaction include methanol, methyl acetate, dimethyl sulfoxide, diethyl sulfoxide, and dimethylformamide. Of these solvents, methanol is preferably used. In its use, the water content of methanol is preferably adjusted to 0.001 to 1% by weight, more preferably 0.003 to 0.9% by weight, and particularly preferably 0.005 to 0.8% by weight.

The saponification reaction is preferably performed at a temperature of 5 to 80 ° C., more preferably 20 to 70 ° C. The time required for the saponification reaction is preferably 5 minutes to 10 hours, more preferably 10 minutes to 5 hours. The saponification reaction can be carried out by either a batch method or a continuous method. After completion of the saponification reaction, the remaining saponification 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 produced by the progress of the saponification reaction, or neutralized by adding a carboxylic acid such as acetic acid. At this time, an alkali metal salt of a carboxylic acid such as sodium acetate is formed. As described above, the raw material PVA preferably contains a predetermined amount of an alkali metal salt of carboxylic acid.

In order to obtain such a PVA, the PVA may be washed with a washing solution containing a lower alcohol such as methanol after saponification. The cleaning liquid may contain 20 parts by mass or less of water with respect to 100 parts by mass of the lower alcohol. Moreover, the said washing | cleaning liquid may contain ester, such as methyl acetate produced | generated in a saponification process. The content of the ester at this time 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 amount of the cleaning solution used for cleaning is preferably 100 parts by weight to 10000 parts by weight, more preferably 150 parts by weight to 5000 parts by weight, with respect to 100 parts by weight of the gel obtained by saponification and PVA swollen with alcohol. More preferably, it is 200 to 1000 parts by mass. 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. The washing method is not particularly limited. For example, PVA (swelled gel) and a washing solution are added to a tank, and the solution is stirred or allowed to stand for 5 to 180 minutes at 5 to 100 ° C. to remove the liquid. A batch method in which the process is repeated until the content of the alkali metal salt of the carboxylic acid is within the above range can be mentioned. Further, there is also a continuous method in which PVA is continuously added from the top of the tower at approximately the same temperature and for the same time as the batch method, and a cleaning liquid is continuously added from the bottom of the tower, and the two are brought into contact with each other.

The alkali metal salt of the carboxylic acid contained in the raw material PVA is obtained by neutralizing the alkali catalyst used in the saponification step, for example, sodium hydroxide, potassium hydroxide, sodium methylate, etc. with carboxylic acid, In addition, the carboxylic acid added for the purpose of suppressing alcoholysis of the vinyl ester monomer such as vinyl acetate used in the polymerization process is neutralized in the saponification process, to stop radical polymerization When a carboxylic acid having a conjugated double bond is used as an inhibitor to be added to the carboxylic acid, 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 1,1-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.

The PVA thus obtained is acetalized to produce polyvinyl acetal used for film production. Although the method of acetalization is not specifically limited, For example, the following method is mentioned. PVA is dissolved in water by heating to 80 to 100 ° C., and then gradually cooled over 10 to 60 minutes to obtain a 3 to 40% by mass aqueous solution of PVA. 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 25 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 a specific PVA described later is used as a raw material, the generation of coarse particles is suppressed from the conventional product, and as a result, foreign matter (undissolved content) is reduced when the resulting polyvinyl acetal is melt-formed. Film can be obtained.

The acid catalyst used in the acetalization reaction is not particularly limited, and any of organic acids and inorganic acids can be used. Examples thereof include acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid. 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. However, when the polyvinyl alcohol of the present invention is used as a raw material, the formation of coarse particles is suppressed, and as a result, when the obtained polyvinyl acetal is melt-formed, a film with reduced foreign matter (undissolved content) is obtained. Obtainable.

The aldehyde used for the acetalization reaction of polyvinyl acetal is not particularly limited, but a conventionally 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 preferable. In the present invention, polyvinyl acetal obtained by using two or more aldehydes in combination can also be used.

In the present invention, as a method for adjusting each value obtained by GPC measurement of a film to fall within the above-mentioned range, 1) a method for forming a film by adding an antioxidant to polyvinyl acetal, and 2) production of a film The method of using specific PVA for the raw material of the polyvinyl acetal used for 3) and the method of forming into a film using the specific polyvinyl acetal are mentioned. You may combine these methods suitably.

The antioxidant used in the method 1) is not particularly limited, and examples thereof include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. Among these, phenolic antioxidants are used. Preferably, 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-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate; 2,6-di-t-butyl-4-methylphenol, 2,6-di-t -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′-thiobi (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-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- ( 3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate) methane, triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) Alkyl-substituted phenolic compounds such as propionate); 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 There is.

Examples of phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2-t-butyl). -4-methylphenyl) phosphite, tris (cyclohexylphenyl) phosphite, 2,2-methylenebis (4,6-dit-butylphenyl) octyl phosphite, 9,10-dihydro-9-oxa-10-phos Phaphenanthrene-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-phospha Monophosphite compounds such as enanthrene; 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-ditridecyl phosphite), 4,4′-isopropylidene-bis (phenyl-dialkyl (C12 To C15) phosphite), 4,4′-isopropylidene-bis (diphenylmonoalkyl (C12 to 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 0.001 to 5 parts by mass, preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polyvinyl acetal. When the amount of the antioxidant is less than 0.001 part by mass, a sufficient effect may not be exhibited, and when it exceeds 5 parts by mass, the effect cannot be improved by increasing the blending amount.

The PVA used in the above method 2) includes a peak top molecular weight (D) measured by a differential refractive index detector when the PVA heated at 120 ° C. for 3 hours is measured by GPC, and an absorptiometric detector The peak top molecular weight (E) measured at (measurement wavelength 280 nm) is the following formula (5)
(DE) / D <0.75 (5)
And the absorbance at the peak top molecular weight (E) is preferably 0.25 × 10 ⁻³ to 3.00 × 10 ⁻³ . The GPC measurement at this time is performed in the same manner as the GPC measurement method for a film described above except for the following points.

In the GPC measurement, “GPC HFIP-806M” manufactured by Showa Denko KK is used as the GPC column. The cell length of the absorptiometric detector is 10 mm. The column temperature during measurement is 40 ° C., and the flow rate is 1.0 ml / min.

In the GPC measurement, PVA heated under the following conditions is measured. After casting an aqueous solution in which the PVA powder is dissolved, the PVA film is obtained by drying at 20 ° C. and 65% RH. The PVA film has a thickness of 30 to 75 μm, preferably 40 to 60 μm. In order to clearly reflect the difference in hue of the sample after heat drying on the difference in absorbance, the film is heated at 120 ° C. for 3 hours using a hot air dryer. From the viewpoint of suppressing heat treatment errors between samples, a gear oven is preferable as the hot air dryer. The PVA thus heated is subjected to GPC measurement.

The peak top molecular weight (D) of the PVA is determined in the same manner as the peak top molecular weight (A) of the film described above, and the peak top molecular weight (E) of the raw material PVA is the same as the peak top molecular weight (B) of the film described above. Ask for it.

The PVA has a peak top molecular weight (D) measured by a differential refractive index detector and a peak top molecular weight (E) measured by an absorptiometric detector (measurement wavelength 280 nm) when GPC measurement is performed by the above-described method. ) Preferably satisfies the following formula (5).
(DE) / D <0.75 (5)

The peak top molecular weight (D) is a value serving as an index of the molecular weight of PVA. On the other hand, the peak top molecular weight (E) is derived from a component present in PVA and having absorption at 280 nm. Usually, since the peak top molecular weight (D) is larger than the peak top molecular weight (E), (DE) / D becomes a positive value. As the peak top molecular weight (E) increases, (DE) / D decreases, and as the peak top molecular weight (E) decreases, (DE) / D increases. That is, when (DE) / D is large, it means that there are many components that absorb ultraviolet light having a wavelength of 280 nm among low molecular weight components in PVA.

When (DE) / D is 0.75 or more, as described above, the low molecular weight component contains more components that absorb ultraviolet light having a wavelength of 280 nm. In this case, foreign matter (undissolved part) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. (DE) / D is more preferably less than 0.70, and still more preferably less than 0.65.

The PVA preferably has an absorbance (measurement wavelength: 280 nm) at a peak top molecular weight (E) of 0.25 × 10 ⁻³ to 3.00 × 10 ⁻³ when GPC measurement is performed by the method described above. If the absorbance is less than 0.25 × 10 ⁻³ , foreign matter (undissolved content) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. On the other hand, if the absorbance exceeds 3.00 × 10 ⁻³ , there may be an increase in the absorption component of 280 nm ultraviolet-visible light in the film, and the coloration resistance of the film and the penetration resistance of the laminated glass are reduced. There is a fear. The absorbance is more preferably 0.50 × 10 ⁻³ to 2.80 × 10 ⁻³ , and further preferably 0.75 × 10 ⁻³ to 2.50 × 10 ⁻³ .

The PVA has a peak top molecular weight (D) measured by a differential refractive index detector and a peak top molecular weight (F) measured by an absorptiometric detector (measurement wavelength: 320 nm) when GPC measurement is performed by the method described above. ) More preferably satisfies the following formula (6).
(DF) / D <0.75 (6)

The peak top molecular weight (F) is measured in the same manner as the peak top molecular weight (E) except that the measurement wavelength in the absorptiometric detector is 320 nm. The peak top molecular weight (F) is derived from a component having absorption at 320 nm, which is present in the raw material PVA. Usually, since the peak top molecular weight (D) is larger than the peak top molecular weight (F), (DF) / D becomes a positive value. As the peak top molecular weight (F) increases, (DF) / D decreases, and as the peak top molecular weight (F) decreases, (DF) / D increases. That is, when (D−F) / D is large, it means that the low molecular weight component in PVA contains many components that absorb ultraviolet rays having a wavelength of 320 nm.

When (D−F) / D is 0.75 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, foreign matter (undissolved part) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. (D−F) / D is more preferably less than 0.70, and particularly preferably less than 0.65.

More preferably, the PVA has an absorbance (measurement wavelength: 320 nm) at a peak top molecular weight (F) of 0.20 × 10 ⁻³ to 2.90 × 10 ⁻³ when GPC measurement is performed by the method described above. . When the absorbance is less than 0.20 × 10 ⁻³ , foreign matter (undissolved content) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. On the other hand, when the absorbance exceeds 2.90 × 10 ⁻³ , there is a possibility that the absorption component of 320 nm ultraviolet-visible light increases in the film, and the coloring resistance of the film and the penetration resistance of the laminated glass may be reduced. There is. The absorbance is more preferably 0.40 × 10 ⁻³ to 2.70 × 10 ⁻³ , and particularly preferably 0.60 × 10 ⁻³ to 2.40 × 10 ⁻³ .

The ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the PVA, which is obtained by the differential refractive index detector in the GPC measurement of PVA described above, is preferably 2.2 to 6.0. Mw and Mn are obtained from a chromatogram obtained by plotting the value measured by the differential refractive index detector with respect to the molecular weight of PVA used when obtaining the above-described peak top molecular weight (D). Therefore, Mw and Mn calculated | required here are the values of PMMA conversion.

When Mw / Mn is less than 2.2, it indicates that the proportion of low molecular weight components is small in PVA. When Mw / Mn is less than 2.2, the number of foreign matters (undissolved parts) in the film may increase. It is more preferable that Mw / Mn is 2.3 or more. On the other hand, when Mw / Mn exceeds 6.0, it shows that the ratio of a low molecular weight component is large in PVA. When Mw / Mn exceeds 6.0, the coloring resistance of the film may be reduced, and the penetration resistance of the obtained laminated glass may be reduced. Mw / Mn is more preferably 4.5 or less, and further preferably 3.0 or less.

The absorbance at the peak top molecular weight (D), the peak top molecular weight (E), the peak top molecular weight (E), the peak top molecular weight (F), and the absorbance at the peak top molecular weight (F) of the PVA so that the above-mentioned conditions are satisfied. Examples of the adjustment method include the following methods.

A) A vinyl ester monomer from which a radical polymerization inhibitor contained in the raw material vinyl ester monomer has been removed in advance is used for 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 even 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 the solvent used for the polymerization, a solvent having a total impurity content 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 radical polymerization of the vinyl ester monomer, 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, 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 in order to suppress the 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, , 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 comprising 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, abietic acid; Conjugated triene having a conjugated structure of three carbon-carbon double bonds such as 1,3,5-hexatriene, 2,4,6-octatriene-1-carboxylic acid, eleostearic acid, tung oil, 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. Further, 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 -The Aromatic compounds such as Eniru 1,3-butadiene.

H) A polyvinyl ester alcohol solution 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.

The desired PVA can be obtained by appropriately combining A) to H). The polyvinyl acetal obtained by acetalizing the PVA thus obtained is preferably used as a raw material for the film.

Further, as the polyvinyl acetal used in the method 3), when the polyvinyl acetal heated at 230 ° C. for 3 hours is measured by GPC, the peak top molecular weight (G) measured by a differential refractive index detector and the light absorption The peak top molecular weight (H) measured by a photometric detector (measurement wavelength: 280 nm) is the following formula (7)
(GH) / G <0.60 (7)
And the absorbance at the peak top molecular weight (B) is 0.50 × 10 ⁻³ to 1.00 × 10 ⁻² . The GPC measurement at this time is performed in the same manner as the GPC measurement method for a film described above except for the following points.

In the GPC measurement, polyvinyl acetal heated under the following conditions is measured. 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 to 800 μm, and is preferably about 760 μm, which is the thickness of a normal laminated glass interlayer film. The polyvinyl acetal thus heated is subjected to GPC measurement.

The peak top molecular weight (G) of the polyvinyl acetal is determined in the same manner as the peak top molecular weight (A) of the film described above, and the peak top molecular weight (H) of the polyvinyl acetal is determined as the peak top molecular weight (B) of the film described above. Find in the same way as

The polyvinyl acetal has a peak top molecular weight (G) measured by a differential refractive index detector and a peak top molecular weight measured by an absorptiometric detector (measurement wavelength 280 nm) when GPC measurement is performed by the method described above. It is preferable that H) satisfy | fills following formula (7).
(GH) / G <0.60 (7)

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

When (GH) / G is 0.60 or more, as described above, the low molecular weight component contains more components that absorb ultraviolet light having a wavelength of 280 nm. In this case, foreign matter (undissolved part) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. (GH) / G is more preferably less than 0.55, and still more preferably less than 0.50.

The polyvinyl acetal preferably has an absorbance (measurement wavelength: 280 nm) at a peak top molecular weight (H) of 0.50 × 10 ⁻³ to 1.00 × 10 ⁻² when GPC measurement is performed by the method described above. . If the absorbance is less than 0.50 × 10 ^-3, there is a possibility that foreign matter in the film (undissolved) increases. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. On the other hand, when the absorbance exceeds 1.00 × 10 ⁻² , there may be an increase in the component that absorbs ultraviolet light having a wavelength of 280 nm in the film, and the coloration resistance of the film and the penetration resistance of the laminated glass are reduced. There is a risk. The absorbance is more preferably 1.50 × 10 ⁻³ to 1.00 × 10 ⁻² , further preferably 1.55 × 10 ⁻³ to 8.50 × 10 ⁻³ , and 1.60 × 10 ⁻³ to 7. Particularly preferred is 0.000 × 10 ⁻³ .

The polyvinyl acetal has a peak top molecular weight (G) measured by a differential refractive index detector and a peak top molecular weight measured by an absorptiometric detector (measurement wavelength: 320 nm) when GPC measurement is performed by the method described above ( More preferably, I) satisfies the following formula (8).
(GI) / G <0.65 (8)

The peak top molecular weight (I) is measured in the same manner as the peak top molecular weight (H) except that the measurement wavelength in the absorptiometric detector is 320 nm. The peak top molecular weight (I) is derived from a component having absorption at 320 nm, which is present in the raw material PVA. Usually, since the peak top molecular weight (G) is larger than the peak top molecular weight (I), (GI) / G becomes a positive value. As the peak top molecular weight (I) increases, (GI) / G decreases, and as the peak top molecular weight (I) decreases, (GI) / G increases. That is, when (GI) / G is large, it means that the low molecular weight component in the polyvinyl acetal contains many components that absorb ultraviolet rays having a wavelength of 320 nm.

When (GI) / G 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, foreign matter (undissolved part) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of the laminated glass obtained using a film cannot be taken. (GI) / G is more preferably less than 0.60, and particularly preferably less than 0.55.

The polyvinyl acetal has an absorbance (measurement wavelength of 320 nm) at a peak top molecular weight (I) of 0.35 × 10 ⁻³ to 4.50 × 10 ⁻³ when GPC measurement is performed by the above-described method. preferable. When the absorbance is less than 0.35 × 10 ⁻³ , foreign matter (undissolved part) in the film may increase. Moreover, there exists a possibility that the performance regarding the coloring resistance of a film, the foreign material (undissolved part) in a film, and the penetration resistance of a film cannot be balanced. On the other hand, when it said absorbance is more than 4.50 × 10 ^-3 is may become more absorption components of 320nm ultraviolet-visible light in the film, a possibility that penetration of the coloring resistance and laminated glass of the film is decreased There is. The absorbance is more preferably 0.75 × 10 ⁻³ to 4.50 × 10 ⁻³ , particularly preferably 0.80 × 10 ⁻³ to 3.50 × 10 ⁻³ , and 0.85 × 10 ⁻³ to 2. .50 × 10 ⁻³ is most preferred.

In the above-mentioned GPC measurement of polyvinyl acetal, the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the polyvinyl acetal measured with a differential refractive index detector is preferably 2.8 to 8.8. . Mw and Mn are obtained from the chromatogram obtained by plotting the values measured by the differential refractive index detector with respect to the molecular weight of polyvinyl acetal used when obtaining the peak top molecular weight (G) described above. Therefore, Mw and Mn calculated | required here are the values of PMMA conversion.

The ratio Mw / Mn (molecular weight distribution) derived from the number average molecular weight (Mn) and the weight average molecular weight (Mw) in terms of PMMA equivalent molecular weight is preferably 2.8 to 8.8. 7 is more preferable, and 3.0 to 8.6 is still more preferable. When Mw / Mn is less than 2.8, the number of foreign matters (undissolved parts) in the film may increase. On the contrary, when Mw / Mn exceeds 8.8, there is a possibility that the coloring resistance of the film is lowered or the penetration resistance of the laminated glass is lowered.

As a means for obtaining such a specific polyvinyl acetal, a method of acetalizing using the specific PVA shown in the above 2) as a raw material can be mentioned.

The film of the present invention preferably contains a plasticizer. The plasticizer 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. As the plasticizer, a mono- or diester of an oligoalkylene glycol having a hydroxyl group at both ends and a carboxylic acid, a diester of a dicarboxylic acid and a hydroxyl group-containing compound, or the like can be used. These can be used alone or in combination of two or more. Examples of oligoalkylene glycols 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 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 carboxylic acid is arbitrary. Of these, monoesters and diesters of triethylene glycol and 2-ethylhexanoic acid are preferable from the viewpoint of handleability (volatility during molding). Dicarboxylic acids include alkylene dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and sebacic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid. An acid etc. are mentioned. Examples of the hydroxyl group-containing compound include methanol, ethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, heptanol, octanol, 2-ethylhexanol, nonaol, decanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, Examples thereof include 2-butoxyethanol and the like, and diesters with the aforementioned dicarboxylic acid compounds. Here, the combination of dicarboxylic acid and a hydroxyl-containing compound is arbitrary.

The content of the plasticizer is not particularly limited as long as the effect of the present invention is not impaired, but is preferably 12 to 200 parts by weight, more preferably 15 to 150 parts by weight with respect to 100 parts by weight of polyvinyl acetal. More preferably, it is 20 to 100 parts by mass. When content of a plasticizer is less than 10 mass parts, there exists a possibility that the softness | flexibility of a film may fall. On the contrary, when the content of the plasticizer exceeds 200 parts by mass, the plasticizer may easily bleed out. In particular, when the film of the present invention is used as an interlayer film for laminated glass, the content of the plasticizer is preferably 10 to 100 parts by mass, more preferably 15 to 90 parts by mass, and still more preferably 100 parts by mass of polyvinyl acetal. Is 20 to 80 parts by mass. When content of a plasticizer is less than 10 mass parts, there exists a possibility that desired softness | flexibility may not be obtained as an intermediate film for laminated glasses. If the content exceeds 100 parts by mass, the desired mechanical properties, in particular the penetration resistance of the laminated glass, may be reduced.

The film of the present invention may contain an ultraviolet absorber, an adhesion adjusting agent, a pigment, a dye, and other conventionally known additives, as long as it is not contrary to the gist of the present invention. Such additives will be described below.

Examples of the ultraviolet absorber include 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-2-hydroxyphenyl) benzotriazole, 2- (2′- Benzotriazole ultraviolet absorbers such as hydroxy-5′-t-octylphenyl) benzotriazole; 2,2,6,6-tetramethyl-4-pipe Lysylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) -2- (3,5-dit -Butyl-4-hydroxybenzyl) -2-n-butyl malonate, 4- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) -1- (2- (3- ( Hindered amine ultraviolet absorbers such as 3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl) -2,2,6,6-tetramethylpiperidine; 2,4-di-t-butylphenyl-3 Benzoate UV absorbers such as, 5-di-t-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate; malonic acid [(4-me Kishifeniru) - methylene] - malonic acid ester ultraviolet absorbers such as dimethyl ester; 2-ethyl-2'-ethoxy - such as oxalic acid anilide-based ultraviolet absorbers such oxalanilide like. These ultraviolet absorbers can be used alone or in combination of two or more. The content of the ultraviolet absorber in the film is not particularly limited, but is preferably 10 to 50,000 ppm, and more preferably 100 to 10,000 ppm. If the content is less than 10 ppm, a sufficient effect may not be exhibited, and even if the content is more than 50,000 ppm, the effect cannot be improved by increasing the content.

The film of the present invention may contain an adhesion adjusting agent in order to appropriately adjust the adhesion with glass. A conventionally well-known thing can be used as an adhesive control agent. For example, sodium salts, potassium salts, magnesium salts of organic acids such as acetic acid, propionic acid, butanoic acid, hexanoic acid, 2-ethylbutanoic acid and 2-ethylhexanoic acid are used. These can be used alone or in combination of two or more. The preferred content of the adhesion modifier varies depending on the type, but the adhesive strength of the resulting film to glass is generally 3 in the Pummel test (Pummel test; described in International Publication No. 03/033583 etc.). It is preferable to adjust so as to be ˜10. In particular, when high penetration resistance is required, the content is preferably adjusted to 3 to 6, and when high glass scattering prevention property is required, the content is adjusted to 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 film is preferably 0.0001 to 1% by mass, more preferably 0.0005 to 0.1% by mass, and 0.001 to 0.03% by mass. Is more preferable.

Moreover, a silane coupling agent is mentioned as another additive for adjusting the said adhesiveness. The content of the silane coupling agent in the film is preferably 0.01 to 5% by mass.

The glass transition temperature of the film of the present invention is not particularly limited and can be appropriately selected depending on the purpose, but is preferably in the range of 0 to 50 ° C., more preferably 0 to 45 ° C., and more preferably 0 to More preferably, it is 40 degreeC. In particular, when the film of the present invention is used as a laminated glass interlayer, the glass transition temperature is preferably in the above range.

The method for producing the film of the present invention is not particularly limited, but a method in which PVA is acetalized to obtain polyvinyl acetal and then the polyvinyl acetal is melt-molded is preferable. As the melt molding method, a method of melt-kneading the obtained polyvinyl acetal, plasticizer and other components using an extruder to form a film is preferable. The resin temperature at the time of extrusion is preferably 150 to 250 ° C, more preferably 170 to 230 ° C. When the resin temperature becomes too high, polyvinyl acetal is decomposed, and the content of volatile substances in the intermediate film after film formation increases. On the other hand, if the temperature is too low, the removal of volatile matter in the extruder becomes insufficient, and the content of volatile substances in the intermediate 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 extruder. The film of the present invention can also be produced by a method in which a film obtained by dissolving or dispersing polyvinyl acetal, a plasticizer and other components in an organic solvent is formed, and then the organic solvent is distilled off.

In the present invention, as the raw material polyvinyl acetal of the film, the film may be formed using only a virgin resin (not containing recycled polyvinyl acetal), but the trim and off-spec products described later are reused. A film may be formed. Usually, for film formation, a film forming apparatus provided with a weighing machine such as a gear pump and a die such as a T die in an extruder is used. Generally, when forming an intermediate film for laminated glass or the like, 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, an off-spec product produced during the production of a film having irregularities on the surface is useful because it can be reused in the same manner as the trim. The film of the present invention has few foreign matters (undissolved content) generated when it is melt-formed. In addition, since the film of the present invention is less colored when heat-treated, the recovered film (trim, off-spec film) can be effectively reused. As a method of feeding the recovered film into the extruder again, a method in which a trim or off-spec film is wound on a roll is unwound and then fed back into the extruder; the trim or off-spec film is put on a roll Examples include a method of cutting a wound product into a certain size and then re-feeding it into an extruder. When the film of the present invention is formed, the ratio of the virgin resin to the recovered film (virgin resin: recovered film) in the raw material can be arbitrarily changed between 0: 100 and 100: 0.

When manufacturing a film by reusing the above trim or off-spec film, the contents of the plasticizer and other components can be adjusted by the following method. A desired film is obtained by adjusting the addition amount of each component to an extruder, analyzing the component of the obtained film.

An interlayer film for laminated glass comprising the film of the present invention is a preferred embodiment of the present invention. Since the film of the present invention is excellent in transparency and flexibility, it can be suitably used as an interlayer film for glass. The thickness of the interlayer film for laminated glass is not particularly limited, but is preferably 0.05 to 5.0 mm, more preferably 0.1 to 2.0 mm, and 0.1 to 1.2 mm. More preferably it is.

The interlayer film for laminated glass may contain a pigment, a dye or the like as necessary.

The shape of the surface of the interlayer film for laminated glass is not particularly limited. However, in consideration of the handleability (foaming property) when laminating with glass, the melt fracture and embossing are performed on the surface in contact with the glass by a conventionally known method. It is preferable that a concavo-convex structure such as is formed. The emboss height is not particularly limited, but is preferably 5 μm to 500 μm, more preferably 7 μm to 300 μm, and still more preferably 10 μm to 200 μm. When the emboss height is less than 5 μm, bubbles formed between the glass and the intermediate film may not be efficiently removed during lamination, and when it exceeds 500 μm, it is difficult to form the emboss. Embossing may be performed on one side of the intermediate film or on both sides, but it is usually preferable to apply it on both sides. The emboss pattern may be regular or irregular.

In order to form such embossing, a conventionally known embossing roll method, profile extrusion method, extrusion lip embossing method using melt fracture, or the like is employed. In particular, the embossing roll method is suitable for stably obtaining an embossed film on 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. Moreover, an embossing roll can also be produced using laser etching. Further, after forming a fine concavo-convex pattern on the roll surface as described above, blasting is performed on the surface using an abrasive such as aluminum oxide, silicon oxide, or glass beads to form a finer concavo-convex pattern. You can also.

In addition, it is preferable to perform a release treatment on the embossing roll used in the embossing roll method. When a roll that has not been subjected to release treatment is used, a trouble that the film cannot be peeled off from the roll tends to occur. For the release treatment, a known method such as silicone treatment, Teflon (registered trademark) treatment, plasma treatment or the like can be used.

A laminated glass obtained 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 either colorless or colored. These may be either transparent or non-transparent. The same type of glass may be laminated, or different types of glass may be laminated. Although the thickness of glass is not specifically limited, It is preferable that it is 100 mm or less. Moreover, there is no restriction | limiting in particular about the shape of the said glass, Even if it is glass which has curvature, such as a simple planar plate glass, a motor vehicle windshield.

The laminated glass can be produced by a conventionally known method, and examples thereof include a method using a vacuum laminator device, 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 is used, for example, the glass and the interlayer film are laminated at 100 to 200 ° C., particularly 130 to 160 ° C. under a reduced pressure of 1 × 10 ⁻⁶ to 3 × 10 ⁻² MPa. 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.

As a production method using a nip roll, there is a method in which after degassing with a roll at a temperature equal to or lower than the flow start temperature of the film, pressure bonding is performed at a temperature close to the flow start temperature. Specifically, for example, there is a method of heating to 30 to 70 ° C. with an infrared heater or the like, then degassing with a roll, further heating to 50 to 120 ° C., and then pressing with a roll.

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 The treatment is preferably carried out at 130 to 145 ° C. for 0.5 to 3 hours under pressure.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. In the following Examples and Comparative Examples, “part” and “%” mean mass basis unless otherwise specified.

[GPC measurement]
(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. As the GPC column, “GPC HFIP-806M” manufactured by Showa Denko KK was used. Moreover, OmniSEC (Version 4.7.0.406) attached to the apparatus was used as analysis software.

(Measurement condition)
The sample was dissolved in HFIP containing 20 mmol / l sodium trifluoroacetate to prepare a solution (concentration 1.00 mg / ml) in which the sample was dissolved. The solution was filtered through a 0.45 μm polytetrafluoroethylene filter and used for measurement.

As the mobile phase, 20 mmol / l sodium trifluoroacetate-containing HFIP 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 PVA viscosity average polymerization degree in a sample 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, monodispersed PMMA (peak top molecular weight: 1944000, 790000, 467400, 271400, 144000, 79250, 35300, 13300, 7100, 1960, 1020, 690) manufactured by Agilent Technologies was measured, and a differential refractive index detector. A calibration curve for converting the elution volume into the PMMA molecular weight was prepared for each of the absorptiometric detectors. The analytical software was used to create each calibration curve. In this measurement, a column in a state where the peaks of standard samples having both molecular weights of 1944000 and 271400 can be separated in the PMMA measurement is used.

In this apparatus, the signal intensity obtained from the differential refractive index detector is expressed in millivolts, and the signal intensity obtained from the absorptiometric detector is expressed in absorbance (abs unit: Absorbance unit).

[Synthesis of polyvinyl acetate]
PVAc-1
A 6L 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 of acetaldehyde (AA) and 50 ppm of acetaldehyde dimethyl acetal (DMA). 945 g of methanol (MeOH) containing 50 ppm of acetaldehyde dimethyl acetal and acetaldehyde content of less than 1 ppm; 1% methanol solution of tartaric acid in an amount of 20 ppm of tartaric acid in VAM was charged. While blowing nitrogen into the flask, the temperature inside the flask was adjusted to 60 ° C. Note that an ethylene glycol / water solution at −10 ° C. was circulated in the reflux tube. A 0.55% by mass methanol solution of di-n-propyl peroxydicarbonate was prepared, and 18.6 mL was added to the flask to initiate polymerization. At this time, the amount of di-n-propyl peroxydicarbonate added 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 the 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 VAM was 35.0%. After the polymerization solution was cooled to room temperature, the inside of the flask was decompressed using a water aspirator to distill off VAM and methanol, thereby precipitating polyvinyl acetate. After 3000 g of methanol was added to the precipitated polyvinyl acetate and the polyvinyl acetate was dissolved while heating at 30 ° C., the pressure in the flask was reduced again using a water aspirator to distill off VAM and methanol. 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 VAM removal rate of 99.8%.

The polymerization degree was measured using a part of the methanol solution of PVAc-1 obtained. A 10% methanol solution of sodium hydroxide was added to the methanol solution of PVAc-1 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 the viscosity average polymerization degree was measured. The degree of polymerization was 1700.

PVAc-2 ~ 22
Polyvinyl acetate (PVAc-2 to 22) was obtained by the same method as PVAc-1 except that the conditions were changed to those described in Table 1. In Table 1, “ND” means less than 1 ppm. The degree of polymerization of each polyvinyl acetate obtained was determined in the same manner as PVAc-1. The results are shown in Table 1.

[Synthesis and Evaluation of PVA]
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 in 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 determined by measuring the amount of sodium in the obtained ash using an ICP emission analyzer “IRIS AP” manufactured 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.

A sample for GPC measurement of PVA-1 was prepared by the following method. After heating at 95 ° C. for 1 hour to dissolve PVA-1 in water, it was cooled to room temperature to obtain a 2% aqueous solution of PVA-1. The obtained aqueous solution was cast on a polyethylene terephthalate film (20 cm × 20 cm) and dried for 1 week under the conditions of 20 ° C. and 65% RH to obtain a PVA film having a thickness of 50 μm. The obtained film was fixed with a clip to a stainless steel metal frame (20 cm × 20 cm, 1 cm wide metal frame) and heat-treated at 120 ° C. for 3 hours in a gear oven. A sample was collected from around the center of the PVA film after the heat treatment.

The obtained sample was subjected to GPC measurement by the above method. FIG. 2 shows the relationship between the molecular weight and the signal intensity measured by the differential refractive index detector obtained by the measurement, and the signal intensity (absorbance) measured by the molecular weight and the absorbance detector (measurement wavelength 280 nm). It is the graph which showed this relationship. 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 (D) measured by the differential refractive index detector obtained from FIG. 2 was 100,000, and the peak top molecular weight (E) measured by the absorptiometric detector (280 nm) was 53,000. It was. The obtained value is expressed by the following formula (DE) / D
The value obtained by substituting for was 0.47. The absorbance (280 nm) at the peak top molecular weight (E) was 1.30 × 10 ⁻³ . These results are also shown in Table 2.

The peak top molecular weight (F) measured with an absorptiometric detector (320 nm) obtained in the same manner as the method for obtaining the peak top molecular weight (E) was 50,000. The peak top molecular weight (D) and the peak top molecular weight (F) are expressed by the following formula (DF) / D
The value obtained by substituting for was 0.50. The absorbance (320 nm) at the peak top molecular weight (F) was 1.05 × 10 ⁻³ . These results are also shown in Table 2.

PVA-2-8, comparative PVA-1-5
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 2 were changed. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 2.

PVA-9, comparative PVA-6, 7
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 (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 3.

PVA-10, comparative PVA-8-10
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 (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 4.

Comparative PVA-11-13
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 (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 5.

Comparative PVA-14-17
Each PVA was synthesized in the same manner as PVA-1 except that the conditions were changed to those shown in Table 6. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 6.

PVA-11-17, comparative PVA-18-21
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 7 were changed. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 7.

PVA-18, comparative PVA-22, 23
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 8 were changed. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 8.

PVA-19, comparative PVA-24, 25
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 9 were changed. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 9.

Comparative PVA-26-28
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 10 were changed. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 10.

Comparative PVA-29-31
Each PVA was synthesized in the same manner as PVA-1, except that the conditions shown in Table 11 were changed. The polymerization degree, saponification degree, and sodium acetate content (sodium mass conversion) of the obtained PVA were measured in the same manner as PVA-1. GPC measurement was performed in the same manner as PVA-1. The results are shown in Table 11.

Comparative PVA-32
Water with respect to vinyl acetate monomer units in methanol and polyvinyl acetate so that the total solid concentration (saponification concentration) is 40% by mass with respect to a 55% by mass methanol solution of polyvinyl acetate in PVAc-3. An 8% methanol solution of sodium hydroxide was added with stirring so that the molar ratio of sodium oxide was 0.005, and the saponification reaction was started at 40 ° C. Note that saponification reaction was performed by adding distilled water so that the water content in the system was 3.0%. One hour after adding the methanol solution of sodium hydroxide, 0.8 mol equivalent of 1% aqueous acetic acid and a large amount of distilled water were added to stop the saponification reaction. The resulting solution was transferred to a dryer, dried at 65 ° C. for 12 hours, and then dried at 100 ° C. for 2 hours to obtain Comparative PVA-32.

The polymerization degree, saponification degree, and sodium acetate content of comparative PVA-32 were measured in the same manner as PVA-1. The degree of polymerization was 300, the degree of saponification was 45.3 mol%, and the sodium acetate content was 1.2% (0.34% in terms of sodium). These results are shown in Table 11. Since Comparative PVA-32 was insoluble in water, film preparation for GPC measurement could not be performed, and GPC measurement could not be performed.

Comparative PVA-33
Water with respect to vinyl acetate monomer units in methanol and polyvinyl acetate so that the total solid concentration (saponification concentration) is 40% by mass with respect to a 55% by mass methanol solution of polyvinyl acetate in PVAc-3. An 8% methanol solution of sodium hydroxide was added with stirring so that the molar ratio of sodium oxide was 0.005, and the saponification reaction was started at 40 ° C. Note that saponification reaction was performed by adding distilled water so that the water content in the system was 1.2%. One hour after adding the methanol solution of sodium hydroxide, 0.8 mol equivalent of 1% aqueous acetic acid and a large amount of distilled water were added to stop the saponification reaction. The resulting solution was transferred to a dryer, dried at 65 ° C. for 12 hours, and then dried at 100 ° C. for 2 hours to obtain Comparative PVA-33.

The polymerization degree, saponification degree, and sodium acetate content of comparative PVA-33 were measured in the same manner as PVA-1. The degree of polymerization was 300, the degree of saponification was 60.2 mol%, and the sodium acetate content was 1.3% (0.36% in terms of sodium). GPC measurement was performed in the same manner as PVA-1. These results are shown in Table 11.

[Synthesis and Evaluation of PVB]
PVB-1
A 10-liter glass container equipped with a reflux condenser, thermometer and squid type stirring blade is charged with 8100 g of ion-exchanged water and 660 g of PVA-1 (PVA concentration 7.5%), and the contents are heated to 95 ° C. Thus, the PVA was completely dissolved. Next, the contents were 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 were added to the vessel, and a butyralization reaction was 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 washed again with ion-exchanged water and 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 12.

(GPC measurement of PVB)
A PVB-1 GPC measurement sample was prepared by the following method. PVB-1 powder was hot-pressed at a pressure of 2 MPa at 230 ° C. for 3 hours and cooled to obtain a polyvinyl acetal film having a size of 30 cm × 30 cm and a thickness of 760 μm. A sample was taken from near the center of the heat-treated film.

The obtained sample was subjected to GPC measurement by the above method. FIG. 3 is a graph showing the relationship between the molecular weight and the value measured by the differential refractive index detector, and the relationship between the molecular weight and the absorbance measured by the 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 (G) measured with the differential refractive index detector obtained from FIG. 3 was 90000, and the peak top molecular weight (H) measured with the absorptiometric detector (280 nm) was 68900. The obtained value is expressed by the following formula (GH) / G
The value obtained by substituting for was 0.23. The absorbance at the peak top molecular weight (H) was 2.21 × 10 ⁻³ . These results are also shown in Table 12.

The peak top molecular weight (I) measured by an absorptiometric detector (320 nm) obtained in the same manner as the method for obtaining the peak top molecular weight (H) was 60000 except that the measurement wavelengths were different. The peak top molecular weight (G) and the peak top molecular weight (I) are expressed by the following formula (GI) / G
The value obtained by substituting for was 0.33. Absorbance at a peak top molecular weight (I) was 1.26 × ^{10 -3.} These results are also shown in Table 12.

PVB-2-8, comparative PVB-1-5
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 12. The results are shown in Table 12.

PVB-9
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 12. The degree of butyralization (degree of acetalization) of PVB is 56.8 mol%, the content of vinyl acetate monomer units is 0.9 mol%, and the content of vinyl alcohol monomer units is 42.3. Mol%.

PVB-10
PVB was synthesized and evaluated in the same manner as PVB-1, except that the amount of n-butyraldehyde added was changed to 365 g. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB is 64.3 mol%, the content of vinyl acetate monomer units is 0.9 mol%, and the content of vinyl alcohol monomer units is 34.8. Mol%.

PVB-11
PVB 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 12. The degree of butyralization (degree of acetalization) of PVB is 79.8 mol%, the content of vinyl acetate monomer units is 0.9 mol%, and the content of vinyl alcohol monomer units is 19.3. Mol%.

Comparative PVB-6
PVB was synthesized and evaluated in the same manner as PVB-1, except that the raw material PVA was changed to comparative PVA-1 and the addition amount of n-butyraldehyde was changed to 271 g. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB was 48.5 mol%, the content of vinyl acetate monomer units was 0.8 mol%, and the content of vinyl alcohol monomer units was 50.7%. Mol%.

Comparative PVB-7
PVB was synthesized and evaluated in the same manner as PVB-9, except that the raw material PVA was changed to comparative PVA-1. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB is 56.8 mol%, the content of vinyl acetate monomer units is 0.8 mol%, and the content of vinyl alcohol monomer units is 42.4. Mol%.

Comparative PVB-8
PVB was synthesized and evaluated in the same manner as PVB-11 except that the raw material PVA was changed to comparative PVA-1. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB is 79.8 mol%, the content of vinyl acetate monomer units is 0.8 mol%, and the content of vinyl alcohol monomer units is 19.4. Mol%.

Comparative PVB-9
PVB was synthesized and evaluated in the same manner as Comparative PVB-6, except that the raw material PVA was changed to Comparative PVA-2. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB was 48.3 mol%, the content of vinyl acetate monomer units was 0.8 mol%, and the content of vinyl alcohol monomer units was 50.9. Mol%.

Comparative PVB-10
PVB was synthesized and evaluated in the same manner as Comparative PVB-7, except that the raw material PVA was changed to Comparative PVA-2. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB is 56.6 mol%, the content of vinyl acetate monomer units is 0.8 mol%, and the content of vinyl alcohol monomer units is 42.6. Mol%.

Comparison PVB-11
PVB was synthesized and evaluated in the same manner as Comparative PVB-8 except that the raw material PVA was changed to Comparative PVA-2. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB is 79.6 mol%, the content of vinyl acetate monomer units is 0.8 mol%, and the content of vinyl alcohol monomer units is 19.6. Mol%.

Comparative PVB-12
PVB was synthesized and evaluated in the same manner as Comparative PVB-6 except that the raw material PVA was changed to PVA-1. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB was 48.2 mol%, the content of vinyl acetate monomer units was 0.9 mol%, and the content of vinyl alcohol monomer units was 50.9. Mol%.

Comparative PVB-13
A 10-liter glass container equipped with a reflux condenser, thermometer and squid type stirring blade is charged with 8100 g of ion-exchanged water and 660 g of PVA-1 (PVA concentration 7.5%), and the contents are heated to 95 ° C. Thus, the PVA was completely dissolved. Next, the contents were gradually cooled to 10 ° C. over about 30 minutes while stirring at 120 rpm, and then 740 g of n-butyraldehyde and 810 mL of 20% hydrochloric acid were added to the vessel, and a butyralization reaction was performed for 150 minutes. It was. Thereafter, the temperature was raised to 80 ° C. over 90 minutes, kept at 80 ° C. for 16 hours, 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 dried to obtain PVB. Comparative PVB-13 was evaluated in the same manner as PVB-1. The results are shown in Table 12. The degree of butyralization (degree of acetalization) of PVB is 87.4 mol%, the content of vinyl acetate monomer units is 0.9 mol%, and the content of vinyl alcohol monomer units is 11.7. Mol%.

PVB-12
A 10-liter glass container equipped with a reflux condenser, thermometer and squid type stirring blade is charged with 8234 g of ion-exchanged water and 526 g of PVA-9 (PVA concentration 6.0%), and the contents are heated to 95 ° C. And completely dissolved. Next, the contents were 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 were added to the vessel, and a butyralization reaction was 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 13. The PVB obtained had a butyralization degree (acetalization degree) of 68.2 mol%, a vinyl acetate monomer unit content of 1.3 mol%, and a vinyl alcohol monomer unit content of It was 30.5 mol%.

Comparative PVB-14, 15
PVB was synthesized and evaluated in the same manner as PVB-12, except that the raw material PVA was changed to that shown in Table 13. The results are shown in Table 13.

PVB-13
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-10 (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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 14. The obtained PVB had a butyralization degree (acetalization degree) of 68.1 mol%, a vinyl acetate monomer unit content of 1.5 mol%, and a vinyl alcohol monomer unit content of It was 30.4 mol%.

Comparative PVB-16-18
PVB was synthesized and evaluated in the same manner as PVB-13, except that the raw material PVA was changed to that shown in Table 14. The results are shown in Table 13.

Comparative PVB-19
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 comparative PVA-11 (PVA concentration 5.0%), and the content was adjusted to 95 ° C. The PVA was completely dissolved by raising the temperature. Next, the contents are gradually cooled to 8 ° C. over about 30 minutes while stirring at 120 rpm, and 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, PVB was obtained by re-washing with ion-exchanged water and drying. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 15.

Comparative PVB-20, 21
PVB was synthesized and evaluated in the same manner as Comparative PVB-19 except that the raw material PVA was changed to that shown in Table 15. The results are shown in Table 15.

Comparative PVB-22
PVB was synthesized and evaluated in the same manner as Comparative PVB-19 except that the raw material PVA was changed to that shown in Table 16. The results are shown in Table 16.

Comparative PVB-23
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 comparative PVA-15 (PVA concentration 7.5%), and the content was adjusted to 95 ° C. The PVA was completely dissolved by raising the temperature. Next, the contents were gradually cooled to 5 ° C. over about 30 minutes while stirring at 120 rpm, and then 402 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid were added to the vessel, and a butyralization reaction was performed for 120 minutes. It was. Thereafter, the temperature was raised to 50 ° C. over 60 minutes, held at 50 ° C. for 120 minutes, and then cooled to room temperature. The precipitated resin was washed with ion-exchanged water 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 16. The obtained PVB had a butyralization degree (acetalization degree) of 68.5 mol%, a vinyl acetate monomer unit content of 1.5 mol%, and a vinyl alcohol monomer unit content of It was 30.0 mol%.

Comparative PVB-24
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 comparative PVA-16 (PVA concentration 7.5%), and the contents were adjusted to 95 ° C. The PVA was completely dissolved by raising the temperature. Next, the contents were gradually cooled to 1 ° C. over about 30 minutes while stirring at 120 rpm, and then 422 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid were added to the vessel, and a butyralization reaction was performed for 120 minutes. It was. Thereafter, the temperature was raised to 45 ° C. over 60 minutes, held at 45 ° 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 16. The obtained PVB had a butyralization degree (acetalization degree) of 68.1 mol%, a vinyl acetate monomer unit content of 1.1 mol%, and a vinyl alcohol monomer unit content of It was 30.8 mol%.

Comparative PVB-25
PVB was synthesized and evaluated in the same manner as Comparative PVB-24 except that the raw material PVA was changed to that shown in Table 16. The results are shown in Table 16.

PVB-14
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-11 (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, and 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, it was rewashed with ion-exchanged water and dried to obtain polyvinyl butyral. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 74.1 mol%, a vinyl acetate monomer unit content of 8.1 mol%, and a vinyl alcohol monomer unit content of It was 17.8 mol%.

PVB-15 ~ 20
PVB was synthesized and evaluated in the same manner as PVB-14 except that the raw material PVA was changed to that shown in Table 17. The results are shown in Table 17.

PVB-21
PVB was synthesized and evaluated in the same manner as PVB-14 except that the amount of n-butyraldehyde added was changed to 269 g. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 55.3 mol%, a vinyl acetate monomer unit content of 8.8 mol%, and a vinyl alcohol monomer unit content of It was 35.9 mol%.

PVB-22
PVB was synthesized and evaluated in the same manner as PVB-14 except that the amount of n-butyraldehyde added was changed to 307 g. The results are shown in Table 17. The PVB obtained had a butyralization degree (acetalization degree) of 63.2 mol%, a vinyl acetate monomer unit content of 8.5 mol%, and a vinyl alcohol monomer unit content of It was 28.3 mol%.

PVB-23
PVB was synthesized and evaluated in the same manner as PVB-14 except that the amount of n-butyraldehyde added was changed to 458 g. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 78.5 mol%, a vinyl acetate monomer unit content of 7.5 mol%, and a vinyl alcohol monomer unit content of It was 14.0 mol%.

Comparative PVB-26-29
PVB was synthesized and evaluated in the same manner as PVB-14 except that the raw material PVA was changed to that shown in Table 17. The results are shown in Table 17.

Comparative PVB-30
PVB was synthesized and evaluated in the same manner as PVB-14 except that the raw material PVA was changed to comparative PVA-18 and the addition amount of n-butyraldehyde was changed to 225 g. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 46.2 mol%, a vinyl acetate monomer unit content of 9.2 mol%, and a vinyl alcohol monomer unit content of It was 44.6 mol%.

Comparative PVB-31
PVB was synthesized and evaluated in the same manner as PVB-21 except that the raw material PVA was changed to comparative PVA-18. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 55.5 mol%, a vinyl acetate monomer unit content of 8.9 mol%, and a vinyl alcohol monomer unit content of It was 35.6 mol%.

Comparative PVB-32
PVB was synthesized and evaluated in the same manner as PVB-23 except that the raw material PVA was changed to Comparative PVA-18. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 78.6 mol%, a vinyl acetate monomer unit content of 7.4 mol%, and a vinyl alcohol monomer unit content of It was 14.0 mol%.

Comparative PVB-33
PVB was synthesized and evaluated in the same manner as Comparative PVB-30 except that the raw material PVA was changed to Comparative PVA-19. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 46.3 mol%, a vinyl acetate monomer unit content of 9.1 mol%, and a vinyl alcohol monomer unit content of It was 44.6 mol%.

Comparative PVB-34
PVB was synthesized and evaluated in the same manner as Comparative PVB-31 except that the raw material PVA was changed to Comparative PVA-19. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 55.2 mol%, a vinyl acetate monomer unit content of 9.0 mol%, and a vinyl alcohol monomer unit content of It was 35.8 mol%.

Comparative PVB-35
PVB was synthesized and evaluated in the same manner as Comparative PVB-32 except that the raw material PVA was changed to Comparative PVA-19. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 78.6 mol%, a vinyl acetate monomer unit content of 7.4 mol%, and a vinyl alcohol monomer unit content of It was 14.0 mol%.

Comparative PVB-36
PVB was synthesized and evaluated in the same manner as Comparative PVB-30 except that the raw material PVA was changed to PVA-11. The results are shown in Table 17. The obtained PVB had a butyralization degree (acetalization degree) of 46.3 mol%, a vinyl acetate monomer unit content of 9.1 mol%, and a vinyl alcohol monomer unit content of It was 44.6 mol%.

Comparative PVB-37
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-11 (PVA concentration 7.5%), and the contents were raised to 95 ° C. Warm to dissolve completely. Next, the content is gradually cooled to 15 ° C. over about 30 minutes while stirring at 120 rpm, 837 g of n-butyraldehyde and 810 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 60 ° C. over 60 minutes, kept at 60 ° C. for 24 hours, 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 17. The PVB obtained had a butyralization degree (acetalization degree) of 86.1 mol%, a vinyl acetate monomer unit content of 5.8 mol%, and a vinyl alcohol monomer unit content of It was 8.1 mol%.

PVB-24
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 526 g of PVA-18 (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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 18. The obtained PVB had a butyralization degree (acetalization degree) of 74.6 mol%, a vinyl acetate monomer unit content of 8.3 mol%, and a vinyl alcohol monomer unit content of It was 17.1 mol%.

Comparative PVB-38, 39
PVB was synthesized and evaluated in the same manner as PVB-24 except that the raw material PVA was changed to that shown in Table 18. The results are shown in Table 18.

PVB-25
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-19 (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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 19. The PVB obtained had a butyralization degree (acetalization degree) of 73.2 mol%, a vinyl acetate monomer unit content of 8.1 mol%, and a vinyl alcohol monomer unit content of It was 18.7 mol%.

Comparative PVB-40, 41
PVB was synthesized and evaluated in the same manner as PVB-25 except that the raw material PVA was changed to that shown in Table 19. The results are shown in Table 19.

Comparative PVB-42
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 comparative PVA-29 (PVA concentration 7.5%), and the content was adjusted to 95 ° C. The PVA was completely dissolved by raising the temperature. Next, the contents were gradually cooled to 10 ° C. over about 60 minutes while stirring at 120 rpm, and then 450 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid were added to the vessel, and a butyralization reaction was performed for 90 minutes. It was. Thereafter, the temperature was raised to 30 ° C. over 30 minutes, held at 30 ° 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 20. The PVB obtained had a butyralization degree (acetalization degree) of 74.3 mol%, a vinyl acetate monomer unit content of 8.0 mol%, and a vinyl alcohol monomer unit content of It was 17.7 mol%.

Comparative PVB-43-44
PVB was synthesized and evaluated in the same manner as Comparative PVB-42 except that the raw material PVA was changed to that shown in Table 20. The results are shown in Table 20.

Comparative PVB-45
PVB was synthesized and evaluated in the same manner as Comparative PVB-42 except that the raw material PVA was changed to that shown in Table 21. The results are shown in Table 21.

Comparative PVB-46
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 comparative PVA-30 (PVA concentration 7.5%), and the content was adjusted to 95 ° C. The PVA was completely dissolved by raising the temperature. Next, the contents were gradually cooled to 5 ° C. over about 60 minutes while stirring at 120 rpm, and then 450 g of n-butyraldehyde and 540 mL of 20% hydrochloric acid were added to the vessel, and a butyralization reaction was performed for 90 minutes. It was. Thereafter, the temperature was raised to 30 ° C. over 30 minutes, held at 30 ° 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 21. The obtained PVB had a butyralization degree (acetalization degree) of 74.3 mol%, a vinyl acetate monomer unit content of 7.9 mol%, and a vinyl alcohol monomer unit content of It was 17.8 mol%.

Comparative PVB-47
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 comparative PVA-31 (PVA concentration 7.5%), and the content was adjusted to 95 ° C. The PVA was completely dissolved by raising the temperature. Next, the contents are gradually cooled to 1 ° C. over about 60 minutes while stirring at 120 rpm, and then 468 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 25 ° C. over 30 minutes, held at 25 ° 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. PVB obtained in the same manner as PVB-1 was evaluated. The results are shown in Table 21. The obtained PVB had a butyralization degree (acetalization degree) of 73.2 mol%, a vinyl acetate monomer unit content of 8.0 mol%, and a vinyl alcohol monomer unit content of It was 18.8 mol%.

Comparative PVB-48
Except that the raw material PVA was changed to comparative PVA-32, synthesis of PVB was attempted in the same manner as comparative PVB-47, but the aqueous solubility of comparative PVA-32 was insufficient and an aqueous solution was not obtained. The synthesis was stopped.

Comparative PVB-49
PVB was synthesized and evaluated in the same manner as Comparative PVB-47 except that the raw material PVA was changed to that shown in Table 21. The results are shown in Table 21.

Example 1
50 parts by mass of PVB-1 powder, 19 parts by mass of triethylene glycol-di-2-ethylhexanoate and 0.014 parts by mass of magnesium acetate as plasticizers were manufactured by Toyo Seiki Seisakusho Co., Ltd. Was melt kneaded 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 product was hot-pressed at 150 ° C. and 5 MPa for 30 minutes to produce a film of 30 cm × 30 cm and a thickness of 760 μm. The obtained film was subjected to GPC measurement and evaluation of foreign matter (undissolved content) as follows.

(GPC measurement)
The obtained film was hot-pressed at 2 MPa and 230 ° C. for 3 hours to heat and then cooled to obtain a heat-treated film. A sample was collected from the vicinity of the center, and 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 signal intensity measured with a differential refractive index detector, and the relationship between the molecular weight and the signal intensity (absorbance) measured with an absorptiometric detector (measurement wavelength 280 nm). is there. 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 by the differential refractive index detector obtained from FIG. 1 was 94000, and the signal intensity (a) at the peak top molecular weight (A) was 108.6 mV. The peak top molecular weight (B) measured with an absorptiometric detector (280 nm) was 45000, and the signal intensity (absorbance, b) at the peak top molecular weight (B) was 1.62 mV (1.62 × 10 ^−3). Absorbance unit). The obtained peak top molecular weight (A) and peak top molecular weight (B) are expressed by the following formula (AB) / A
The value obtained by substituting for was 0.52. The results are also shown in Table 22.

Except that the measurement wavelength is different, the peak top molecular weight (C) measured with an absorptiometric detector (320 nm) obtained in the same manner as the method for obtaining the peak top molecular weight (B) is 47000, and the peak top molecular weight The signal intensity (absorbance, c) in (C) was 1.01 mV (1.01 × 10 ⁻³ absorption unit). 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 0.50. The results are also shown in Table 22.

As a monodispersed PMMA, American Polymer Standard Corp. “PMMA85K” (weight average molecular weight 85450, number average molecular weight 74300, intrinsic viscosity 0.309) manufactured by the company was used. The monodispersed PMMA was measured by GPC by the above method. The signal intensity (x) at the peak top molecular weight measured with a differential refractive index detector, which was determined in the same manner as the method for determining the peak top molecular weight (A), was 390.82 mV. In addition, the signal intensity (absorbance, y) at the peak top molecular weight measured with an absorptiometric detector (220 nm) obtained in the same manner as the method for determining the peak top molecular weight (B) was 269.28 mV (0.26928 absorber). Unit).

Signal intensity (a), peak top molecular weight (b), signal intensity (x) and signal intensity (y) are expressed by the following formula (b / y) / (a / x)
The value obtained by substituting for was 2.16 × 10 ⁻² . The results are also shown in Table 22.

Signal intensity (a), peak top molecular weight (c), signal intensity (x), and signal intensity (y) are represented by the following formula (c / y) / (a / x)
The value obtained by substituting for was 1.34 × 10 ⁻² . The results are also shown in Table 22.

(Undissolved content in the film)
The obtained 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. The total number of foreign substances in 20 laminated glasses was determined and evaluated according to the following criteria.
A: 0 (pieces / 20 sheets)
B: 1 (20 pieces)
C: 2-3 (pieces / 20 pieces)
D: 4-8 (pieces / 20 pieces)
E: 9 or more (pieces / 20 sheets)

(Coloring resistance of film)
The same kneaded material used for the production of the above-described film containing PVB-1 was produced. To 34.5 parts by mass of the kneaded product, 25 parts by mass of PVB-1 powder, 9.5 parts by mass of triethylene glycol-di-2-ethylhexanoate and 0.007 parts by mass of magnesium acetate were added, and again It was melt-kneaded under the same conditions as when the kneaded product was produced. The operation of adding PVB-1 powder, triethylene glycol-di-2-ethylhexanoate and magnesium acetate to the kneaded material obtained and kneading was repeated three more times. Using the obtained kneaded material, a film was produced in the same manner as the above-described method for producing a film containing PVB-1. And the laminated glass was produced using the said film similarly to the preparation method of the laminated glass described in the term of "the undissolved part in a film." Yellowness (YI) of the laminated glass obtained here (using PVB heated repeatedly) and the laminated glass obtained using the above “undissolved content in film” (using virgin PVB) The color resistance was evaluated according to the following criteria based on the difference in yellowness (ΔYI) between the two. 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 22.
A: Less than 0.3 B: 0.3 or more and less than 0.5 C: 0.5 or more and less than 1.0 D: 1.0 or more and less than 2.0 E: 2.0 or more

(Penetration resistance of laminated glass)
The same film as that prepared using PVB repeatedly melt-kneaded PVB described in the section "Film resistance" was prepared. The film was conditioned at 23 ° C. and 28% RH for 24 hours, and then sandwiched between two transparent glasses (30 cm × 30 cm). Pre-adhesion was performed by passing a press roll. 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 laminated glass (6 sheets in total). The obtained laminated glass was evaluated according to the method shown in the penetration resistance test of JIS R 3212 (automotive safety glass test method) and JIS R 3211 (automotive safety glass). That is, after the laminated glass was temperature-controlled at 23 ° C. for 4 hours, it was placed horizontally on a dedicated support frame, and a steel ball having a mass of 2260 g and a diameter of 82 mm was freely dropped from a height of 4 m onto the central portion of the laminated glass. When the steel ball penetrated within 5 seconds after the collision, it was determined as “penetration”. Six laminated glasses were tested, and if all did not penetrate, it was determined to be acceptable. In the case where there were 5 pieces that did not penetrate, a retest was conducted. If all 6 pieces did not penetrate, the test was accepted. The results are shown in Table 22.

Examples 2 to 8 and Example 11, Comparative Examples 1 to 5, 8, 11 and 13
A film was prepared and evaluated in the same manner as in Example 1 except that PVB shown in Table 22 was used instead of PVB-1. The results are shown in Table 22.

Examples 9 and 10, Comparative Examples 6, 7, 9, 10 and 12
The film was prepared in the same manner as in Example 1 except that PVB shown in Table 22 was used instead of PVB-1, and dibutoxyethyl adipate was used instead of triethylene glycol-di2-ethylhexanoate. Fabrication and evaluation were performed. The results are shown in Table 22.

Table 22 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 1700 as a raw material. The films of the present invention (Examples 1 to 11) have little undissolved content in the film and are excellent in coloration resistance of the film, and also have excellent penetration resistance of the laminated glass produced using the film of the present invention. It was. On the other hand, the film (Comparative Example 1 to Comparative Example 13) that did not satisfy the conditions defined in the present invention had any performance deteriorated.

Example 12
PVB-12 was used as the PVB (powder) used in the preparation of the kneaded product, the amount thereof was changed to 46 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was changed to 23 parts by mass. Except for the above, production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 1. The results are shown in Table 23. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

The amount of PVB (PVB-12) powder added to the kneaded material was 23 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was added to the kneaded material. Except for changing to 11.5 parts by mass, the production of a film (using PVB repeatedly heated), the coloration resistance test of the film, and the penetration resistance test of laminated glass were performed in the same manner as in Example 1. . The results are shown in Table 23.

Comparative Examples 14 and 15
A film was prepared and evaluated in the same manner as in Example 12 except that PVB shown in Table 23 was used instead of PVB-12. The results are shown in Table 23.

Table 23 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 2400 as a raw material. The film of the present invention (Example 12) had little undissolved content in the film, was excellent in the color resistance of the film, and was also excellent in the penetration resistance of the laminated glass produced using the film. On the other hand, any of the films (Comparative Examples 14 and 15) that did not satisfy the conditions defined in the present invention deteriorated.

Example 13
The use of PVB-13 as PVB (powder) used for the preparation of the kneaded product, the amount thereof was changed to 40.6 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 28.4. Except having changed into the mass part, it carried out similarly to Example 1, and produced the film (thing using PVB of virgin), GPC measurement, and the undissolved part measurement in a film. The results are shown in Table 24. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

The amount of PVB (PVB-13) powder newly added to the kneaded product was 20.3 parts by mass, and triethylene glycol di-2-ethylhexanoate was used. Production of a film (using PVB repeatedly heated), color resistance test of film and penetration resistance test of laminated glass, except that the amount was changed to 14.2 parts by mass, respectively. Went. The results are shown in Table 24.

Comparative Examples 16-18
A film was prepared and evaluated in the same manner as in Example 13 except that PVB shown in Table 24 was used instead of PVB-13. The results are shown in Table 24.

Table 24 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 3600 and 5500 as a raw material. The film of the present invention (Example 13) had little undissolved content in the film, was excellent in the color resistance of the film, and was also excellent in the penetration resistance of the laminated glass produced using the film. On the other hand, any of the films (Comparative Examples 16 to 17) that did not satisfy the conditions defined in the present invention deteriorated. When polyvinyl acetal having a polymerization degree of 5500 was used as a raw material (Comparative Example 18), the melt viscosity was too high, and a film could not be produced.

Comparative Examples 19-21
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 25, the amount was changed to 50.4 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 18 Except for changing to 0.6 parts by mass, the production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were carried out in the same manner as in Example 1. The results are shown in Table 25. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

The amount of PVB powder (shown in Table 25) to be newly added to the kneaded product was 25.2 parts by mass, and triethylene glycol-di-2-ethylhexano was used. Except that the amount of ate was changed to 9.3 parts by mass, production of a film (using repeatedly heated PVB), film coloring resistance test, and penetration resistance of laminated glass, except that the amount of ate was changed to 9.3 parts by mass, respectively A sex test was performed. The results are shown in Table 25.

Table 25 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 1200 as a raw material. In all cases, the penetration resistance of the laminated glass was insufficient.

Comparative Example 22
The PVB (powder) used for the preparation of the kneaded product was changed to that shown in Table 26, the amount was 51.8 parts by mass, and the amount of triethylene glycol-di-2-ethylhexanoate was 17.2. Except having been set as the mass part, it carried out similarly to Example 1, and produced the film (thing using PVB of virgin), GPC measurement, and the undissolved part measurement in a film. The results are shown in Table 26. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

25.9 parts by mass of powder of PVB (shown in Table 26) to be newly added to the kneaded product, triethylene glycol di-2-ethylhexanoate was used. The production of a film (using PVB repeatedly heated), the color resistance test of the film, and the penetration resistance test of the laminated glass were carried out in the same manner as in Example 1 except that the amount of 8.6 parts by mass was changed. went. The results are shown in Table 26.

Comparative Example 23
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 26, the amount was changed to 57.5 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 11 Except that it was changed to 0.5 parts by mass, production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 1. The results are shown in Table 26. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

The amount of PVB powder (shown in Table 26) to be newly added to the kneaded material was 28.8 parts by mass, and triethylene glycol-di-2-ethylhexanoate. The production of the film (using PVB repeatedly heated), the coloration resistance test of the film, and the penetration resistance of the laminated glass, except that the amount of each was changed to 5.7 parts by mass, respectively. A test was conducted. The results are shown in Table 26.

Comparative Examples 24 and 25
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 26, the amount was changed to 61.4 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 7 Except for changing to 0.6 parts by mass, the production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were carried out in the same manner as in Example 1. The results are shown in Table 26. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

30.7 parts by mass of powder of PVB (shown in Table 26) to be newly added to the kneaded product, triethylene glycol-di-2-ethylhexanoate was used. Production of a film (using repeatedly heated PVB), film coloring resistance test and penetration resistance of laminated glass, except that the amount of each was changed to 3.8 parts by mass A test was conducted. The results are shown in Table 26.

Table 26 shows the evaluation results of films made of polyvinyl acetal having a polymerization degree of 150 to 1000 as a raw material. In all cases, the penetration resistance of the laminated glass was insufficient.

Examples 14 to 20, 23, Comparative Examples 26 to 29, 32, 35, 37
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 27, the amount was changed to 40 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 24 parts by mass. Except that it was changed to, production of a film (one using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 1. The results are shown in Table 27. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

Use of the above kneaded product, change of the amount thereof to 32 parts by mass, and addition of 20 parts by mass of powder of PVB (shown in Table 27) newly added to the kneaded product, triethylene glycol Example 1 except that the amount of di-2-ethylhexanoate was changed to 12 parts by mass and the operation of adding PVB or the like to the kneaded product and kneading (4 times in Example 1) was changed to 2 times. In the same manner as described above, production of a film (using PVB heated repeatedly), a coloration resistance test of the film, and a penetration resistance test of the laminated glass were performed. In addition, about the coloring resistance test, the coloring resistance was evaluated according to the following criteria from the difference in yellowness (ΔYI) between the two. The results are shown in Table 27.
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

Examples 21 and 22, Comparative Examples 30, 31, 33, 34 and 36
The film was prepared in the same manner as in Example 14 except that the one shown in Table 27 was used instead of PVB-14 and dibutoxyethyl adipate was used instead of triethylene glycol-di2-ethylhexanoate. Fabrication and evaluation were performed. The results are shown in Table 27.

Table 27 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 1700 as a raw material. The films of the present invention (Examples 14 to 23) have little undissolved content in the film and are excellent in coloration resistance of the film, and also have excellent penetration resistance of the laminated glass produced using the film of the present invention. It was. On the other hand, any of the films (Comparative Example 26 to Comparative Example 37) that did not satisfy the conditions defined in the present invention deteriorated.

Example 24
PVB-24 was used as the PVB (powder) used for the preparation of the kneaded product, the amount thereof was changed to 36.6 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 27.4. Except having changed into the mass part, it carried out similarly to Example 14, and produced the film (thing using PVB of virgin), GPC measurement, and the undissolved part measurement in a film. The results are shown in Table 28. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

The use of the above kneaded material, the amount of powder of PVB (shown in Table 28) to be newly added to the kneaded material was 18.3 parts by mass, triethylene glycol di-2-ethylhexanoate Production of a film (using repeatedly heated PVB), film coloration resistance test, and laminated glass penetration resistance test, except that the amount was changed to 13.7 parts by mass, respectively. Went. The results are shown in Table 28.

Comparative Examples 38 and 39
A film was prepared and evaluated in the same manner as in Example 24 except that PVB shown in Table 28 was used instead of PVB-24. The results are shown in Table 28.

Table 28 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 2400 as a raw material. The film of the present invention (Example 24) had little undissolved content in the film, was excellent in coloration resistance of the film, and was also excellent in penetration resistance of the laminated glass produced using the film of the present invention. On the other hand, any of the films (Comparative Examples 38 and 39) that did not satisfy the conditions defined in the present invention deteriorated.

Example 25
PVB-25 was used as the PVB (powder) used in the preparation of the kneaded product, the amount thereof was changed to 32 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was changed to 32 parts by mass. Except that, the production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 14. The results are shown in Table 29. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

The use of the above kneaded product, the amount of PVB powder (shown in Table 29) to be newly added to the kneaded product was 16 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was Except having changed to 16 parts by mass, respectively, production of a film (using PVB repeatedly heated), coloration resistance test of the film, and penetration resistance test of the laminated glass were performed in the same manner as in Example 14. The results are shown in Table 29.

Comparative Examples 40 and 41
A film was prepared and evaluated in the same manner as in Example 25 except that PVB shown in Table 28 was used instead of PVB-25. The results are shown in Table 29.

Table 29 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 3600 as a raw material. The film of the present invention (Example 25) had little undissolved content in the film, was excellent in coloration resistance of the film, and was also excellent in penetration resistance of the laminated glass produced using the film of the present invention. On the other hand, any of the films (Comparative Examples 40 and 41) that did not satisfy the conditions defined in the present invention deteriorated.

Comparative Examples 42 to 44
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 30, the amount was changed to 41.6 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 22 Except for the change to 4 parts by mass, production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 14. The results are shown in Table 30. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

Using the above kneaded product, the amount of powder of PVB (shown in Table 30) to be newly added to the kneaded product was 20.8 parts by mass, of triethylene glycol di-2-ethylhexanoate. Production of a film (using repeatedly heated PVB), coloration resistance test of film and penetration resistance test of laminated glass except that the amount was changed to 11.2 parts by mass, respectively. Went. The results are shown in Table 30.

Table 30 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 1200 as a raw material. In all cases, the penetration resistance of the laminated glass was insufficient.

Comparative Example 45
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 31, the amount was changed to 42.9 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 21 Except that the content was changed to 1 part by mass, production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 14. The results are shown in Table 31. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

Using the above kneaded material, the amount of PVB powder (shown in Table 31) to be newly added to the kneaded material was 21.5 parts by mass, of triethylene glycol di-2-ethylhexanoate. Production of a film (using repeatedly heated PVB), film coloration resistance test, and laminated glass penetration resistance test, except that the amount was changed to 10.5 parts by mass, respectively. Went. The results are shown in Table 31.

Comparative Example 46
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 31, the amount was changed to 49.2 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 14 Except for the change to 8 parts by mass, production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were carried out in the same manner as in Example 14. The results are shown in Table 31. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

Using the above kneaded product, the amount of PVB powder (shown in Table 31) to be newly added to the kneaded product was 24.6 parts by mass, triethylene glycol-di-2-ethylhexanoate Production of a film (using repeatedly heated PVB), film coloration resistance test, and laminated glass penetration resistance test, except that the amount was changed to 7.4 parts by mass, respectively. Went. The results are shown in Table 31.

Comparative Examples 47-49
The PVB (powder) used in the preparation of the kneaded product was the one shown in Table 31, the amount was changed to 55.7 parts by mass, and the amount of triethylene glycol di-2-ethylhexanoate was 8 Except that the content was changed to 3 parts by mass, production of a film (using virgin PVB), GPC measurement, and measurement of undissolved content in the film were performed in the same manner as in Example 14. The results are shown in Table 31. A part of the kneaded material produced at this time was subjected to production of a film (using PVB heated repeatedly) shown below.

Using the above kneaded product, the amount of PVB powder (added in Table 31) to be newly added to the kneaded material was 27.9 parts by mass, triethylene glycol-di-2-ethylhexanoate Production of a film (using repeatedly heated PVB), film coloring resistance test, and laminated glass penetration resistance test, except that the amount was changed to 4.1 parts by mass, respectively. Went. The results are shown in Table 31.

Table 31 shows the evaluation results of films made from polyvinyl acetal having a polymerization degree of 300 to 1000 as a raw material. In all cases, the penetration resistance of the laminated glass was insufficient.

Claims

A film containing polyvinyl acetal having a degree of acetalization of 50 to 85 mol%, a content of vinyl ester monomer units of 0.1 to 20 mol%, and a viscosity average polymerization degree of 1400 to 5000, A film satisfying (1) and (2).
(AB) / A <0.80 (1)
1.00 × 10 −2 <(b / y) / (a / x) <2.00 × 10 −1 (2)
Where
A: When the film heated at 230 ° C. for 3 hours was measured by gel permeation chromatography, the peak top molecular weight of the polymer component measured by the differential refractive index detector a: the signal intensity B at the peak top molecular weight (A) : When the film heated at 230 ° C. for 3 hours was measured by gel permeation chromatography, the peak top molecular weight b of the polymer component measured by an absorptiometric detector (measurement wavelength 280 nm): in peak top molecular weight (B) Signal intensity x: Signal intensity at peak top molecular weight measured by differential refractive index detector when monodispersed polymethyl methacrylate is measured by gel permeation chromatography y: The monodispersed polymethyl methacrylate is gel permeated Eation chroma When the chromatography measurement, a signal intensity at the peak top molecular weight measured by spectrophotometric detector (measuring wavelength 220 nm).
The film of Claim 1 which satisfy | fills following formula (3) and (4).
(AC) / A <0.80 (3)
5.00 × 10 −3 <(c / y) / (a / x) <7.00 × 10 −2 (4)
Where
A: a, x, y same as the above formula (1) C: same as the above formula (2) C: Absorbance detector when the film heated at 230 ° C. for 3 hours is measured by gel permeation chromatography ( The peak top molecular weight c of the polymer component measured at a measurement wavelength of 320 nm) is the signal intensity at the peak top molecular weight (C).
The film according to claim 1 or 2, wherein the polyvinyl acetal is polyvinyl butyral.
The film according to any one of claims 1 to 3, further comprising a plasticizer.
The film according to any one of claims 1 to 4, which contains triethylene glycol di-2-ethylhexanoate as a plasticizer.
Polyvinyl alcohol was acetalized to obtain a polyvinyl acetal having an acetalization degree of 50 to 85 mol%, a vinyl ester monomer unit content of 0.1 to 20 mol%, and a viscosity average polymerization degree of 1400 to 5000. 6. The method for producing a film according to claim 1, wherein the polyvinyl acetal is melt-molded.
An interlayer film for laminated glass comprising the film according to any one of claims 1 to 5.
A laminated glass obtained by bonding a plurality of glass plates using the interlayer film for laminated glass according to claim 7.