JPH0717745A - Polyvinylacetal resin composition and intermediate film for laminated glass using the same - Google Patents

Abstract

PURPOSE:To improve transparency, adhesiveness to glass, impact resistance, biodegradability and molding properties, etc., of a polyvinylactal resin composition by blending a specific polyvinylacetal resin and poly(epsilon-caprolactone) together. CONSTITUTION:The specific polyvinylacetal resin is obtained by acetalizing PVA having a 300 to 3000 average degree of polymerization with an aldehyde compound having <=11 carbon atoms in 40 to 85mol% degree of acetalization. 55 to 95 pts.wt. of the polyvinyl acetal resin and 45 to 5 pts.wt. of the poly(epsilon-caprolactone) represented by the formula, wherein n is 10 to 2000, are blended together by heating and melting them at 100 to 200 deg.C to obtain the objective polyvinylacetal resin composition. Alternatively, they are blended together by dissolving them into a solvent and thereafter the solvent is removed by evaporating it to obtain the resin composition. At the time of using the polyvinylacetal resin composition as an intermediate film for the laminated glass, the polyvinylacetal resin has preferably a 50 to 85mol% degree of acetalization and the blending ratio of the poly(epsilon-caprolactone) is preferably 10 to 40 pts.wt. Further an ultraviolet absorber, ultraviolet stabilizer and antioxidant are added to the polyvinylacetal resin composition at need and the resulting composition is melted and kneaded and then formed into a film having 0. 1 to 2.0mm thickness to be used as the intermediate film for the laminated glass.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyvinyl acetal resin composition and an interlayer film for laminated glass using the same.

[0002]

2. Description of the Related Art Polyvinyl acetal resin is transparent,
It is a material that exhibits good adhesion to glass and good compatibility with plasticizers. Polyvinyl butyral is an interlayer film for laminated glass, laminated between glass and glass, for automobiles,
It is used as windshields for trains and aircraft, and as window glass for buildings. (Japanese Patent Publication No. 41-1326
No. 7) Polyvinyl butyral, which is used as an interlayer film for laminated glass, is inferior in moldability and is therefore plasticized with a plasticizer. However, the plasticizer bleeds out on the surface after a long period of time. Then, the transparency was lowered and the adhesive strength was lowered. On the other hand, poly (ε-caprolactone) has been known as a material having compatibility with polyvinyl formal and polyvinyl butyral, but no study has been made on its practicality. ("Practical
Biodegradable plastic "issued by CMC in June 1992)

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, the present invention has an object to have high strength and biodegradability without impairing the transparency which is a characteristic of polyvinyl acetal resin. And, to provide a polyvinyl acetal resin composition having excellent moldability, further using the composition, excellent in adhesiveness to glass and moldability, and in transparency and impact resistance. An object of the present invention is to provide an interlayer film for laminated glass, which can obtain excellent laminated glass.

[0004]

The polyvinyl acetal resin used in the present invention is, for example, polyvinyl alcohol.
It is obtained by acetalizing a vinyl ester with an aldehyde compound, and usually has an acetal group, a hydroxyl group and an acetyl group in the ethylene group of the main chain. The above-mentioned aldehyde compound is not particularly limited, but the carbon number thereof is preferably 11 or less because the mechanical properties of polyvinyl acetal decrease and the impact resistance of the laminated glass decreases as the carbon number increases. The aldehyde compound may be linear, branched, or cyclic, and includes, for example, formaldehyde, acetaldehyde, propionaldehyde, n.
-Butyraldehyde, n-valeraldehyde, isobutyraldehyde, n-hexylaldehyde, 2-ethylbutyraldehyde, n-heptylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, benzaldehyde, cinnamua, cyclohexylaldehyde, Etc. These may be used alone or in combination of two or more.

Acetate of the above polyvinyl acetal resin
When the degree of polymerization is low, the moldability of the resulting composition is low, and when it is high, the compatibility with poly (ε-caprolactone) is low, and the transparency of the finally obtained laminated glass is low, It is preferably 40 to 85 mol%,
More preferably, it is 50 to 75 mol%.

The above-mentioned polyvinyl alcohol is obtained by saponifying polyvinyl acetate, and when the average degree of polymerization thereof is low, the strength of the polyvinyl acetal is lowered and the finally obtained laminated glass has a high resistance. Since the impact property decreases and the moldability of the resulting composition decreases when the impact property increases, 300 to 3000 is preferable, and 100 is more preferable.
0 to 2000.

When the average degree of polymerization of the poly (ε-caprolactone) represented by the general formula (1) is low, the compatibility with the polyvinyl acetal resin is low and the composition is bleed out. However, if it is higher, the moldability of the obtained composition is lowered, so that it is 10 to 2000.

[0008]

[Chemical 2]

As the method for producing the above poly (ε-caprolactone), for example, a method in which ε-caprolactone is thermally polymerized at a high temperature, a method in which a catalyst containing Sn or Ti is used for polymerization, a low temperature Al, Mg or Examples include a method of polymerizing using an alkoxide such as Zn or an organic metal catalyst.

When the content of the above poly (ε-caprolactone) is low, the plasticizing effect on the polyvinyl acetal resin is insufficient, and the moldability of the resulting composition is lowered. Since the transparency of the laminated glass obtained is lowered, it is preferably 5 to 45 parts by weight in the composition.

The composition of the present invention is as described above, but if necessary, a plasticizer and an ultraviolet absorber and an ultraviolet stabilizer may be added in order to improve weather resistance. Further, in order to improve thermal stability, an antioxidant, a thermal stabilizer, etc. may be added, and a coloring agent may be added.

As the plasticizer, for example, a plasticizer such as a monobasic acid ester or a polybasic acid ester, an organic phosphoric acid-based plasticizer or an organic phosphorous acid-based plasticizer is used, but preferably triethylene glycol is used. -Di-2-ethylbutyrate, triethyleneglycol-di-2-ethylhexoate,
Di-butyl sebacate, di-butyl carbitol adipate and the like are used.

Examples of the ultraviolet absorber include those having an effective absorption ultraviolet wavelength of 300 to 340 nm, and for example, benzotrial type, benzophenone type and cyanoacrylate type are preferably used. Examples of the benzotriazole-based ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2
-(2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t
-Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-
Di-t-butylphenyl) benzotriazole, 2-
(2'-Hydroxy-3 ', 5'-di-t-butylphenyl) 5-chlorobenzotriazol, 2- (2'-hydroxy-3', 5'-di-t-aminophenyl) benzotriazo -L, 2- [2'-hydroxy-3'-
(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole and the like.

As the benzophenone type ultraviolet absorber,
For example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-
4-dodecyloxybenzophenone, 2,2'-dihydrooxy-4-methoxybenzophenone, 2,2'-di-hydroxy-4,4'-dimethoxybenzophenone,
2-hydroxy-4-methoxy-5-sulfobenzophenone and the like can be mentioned.

Examples of the cyanoacrylate type ultraviolet absorber include 2-ethylhexyl-2-cyano-3,
3'-diphenyl acrylate, ethyl-2-cyano-
3,3'-diphenyl acrylate and the like can be mentioned.

Examples of the stabilizer against ultraviolet rays include:
A hindered amine-based or metal complex salt-based UV stabilizer is preferably used. As the hindered amine-based UV stabilizer, for example, bis (2,2,6,6-tetramethyl-
4-piperidyl) sebacate, compounds commercially available under the following trade names and the like can be mentioned. Product name; SanolLS
-770, Sanol LS-765, Sanol L
S-2626: Chimassob-944LD, Th
inuvin-662, Thinuvin-622L
D, Mark LA-57, Mark LA-77, M
ark LA-62, Mark LA-67, Mark
LA-63, Mark LA-68, Mark LA
-82, Mark LA-87, GoodriteUV
-3040 etc. are mentioned.

Examples of the metal complex salt type ultraviolet stabilizer include nickel [2,2 'thiobis (4-t-octyl)].
Phenolate] normal butylamine, nickel dibutyldithiocarbamate, nickel bis [o-ethyl 3,
5 (di-t-butyl-4-hydroxybenzyl)] phosphate, cobalt dicyclohexyldithiophosphate, [1-phenyl, 3-methyl, 4-decanonyl, pyrazolate (5) ₂ ] nickel, etc. Can be mentioned.

If the addition amount of the above-mentioned UV absorber and UV-resistant stabilizer is small, the effect of preventing deterioration by UV rays is small. Therefore, if the addition amount is large, the transparency of the laminated glass obtained decreases, and the polyvinyl acetal resin is added. It is preferable to add 0.01 to 5.0 parts by weight to the total weight of poly (ε-caprolactone) and poly (ε-caprolactone).
3 to 3.0 parts by weight.

As the above-mentioned antioxidant, a phenol type,
Sulfur-based or phosphorus-based ones can be used, for example, 2,6-di-
t-Butyl-p-cresol (BHT), butylated hydroxyanisole (BHA), 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-ethyl-6-
Butylphenol), 2,2'-methylene-bis- (4
-Methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol),
4,4'-butylidene-bis- (3-methyl-6-t-
Butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, tetrakis [methylene-3- (3 ', 5'di-t-
Butyl-4'-hydroxyphenyl) propionate]
Methane, 1,3,5-trimethyl-2,4,6, tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene, bis [3,3'-bis- (4'-hydroxy) -3'-t-Butylphenyl) butyric acid] glycol ester and the like are preferably added.

If the amount of the antioxidant added is small, the sufficient antioxidant effect cannot be obtained when the interlayer film for laminated glass is formed, and if it is large, the transparency of the laminated glass obtained is decreased, so that the polyvinyl acetate is added. Resin is preferably added in an amount of 0.01 to 3 parts by weight, more preferably 0.2 to 1.5, relative to the total weight of the resin and poly (ε-caprolactone).
Parts by weight.

The antioxidant is preferably added at the time of producing the polyvinyl acetal resin or at the time of adding a plasticizer which is added as necessary.

It is preferable that a heat stabilizer and an additive for adjusting the adhesiveness between the interlayer film and the glass are further added to the interlayer film for laminated glass. As a heat stabilizer,
Examples of surfactants include sodium lauryl sulfate and alkylbenzene sulfonic acid.

The heat stabilizer is preferably added at the time of producing the polyvinyl acetal resin, or at the time of adding the plasticizer added as necessary.

A carboxylic acid metal salt is used as an additive for adjusting the adhesiveness to the glass.
Potassium salts such as octylic acid, hexylic acid, acetic acid, formic acid,
Examples thereof include sodium salt, calcium salt, magnesium salt and the like.

The additives for adjusting the adhesiveness with the glass are added at the time of producing the acetal resin or at the time of adding the polyvinyl acetal resin and a plasticizer which is optionally added. Preferably.

As a method for producing a composition comprising the polyvinyl acetal resin of the present invention and poly (ε-caprolactone), a method of heating and melting to mix or a method of dissolving in a solvent to form a solution There is a method of removing the solvent by evaporation. Examples of the apparatus for melt mixing include a plastomill, a pressure kneader, a Banbury mixer, an extrusion kneader, and the like.

Melt mixing is performed with poly (ε-caprolactone).
It is preferable that the temperature is not less than 220 ° C., which is a temperature not lower than the melting point of and the temperature at which the polyvinyl acetal resin does not thermally decompose. In particular, a good composition can be obtained at a temperature of 100 ° C to 200 ° C.

As a method of dissolving in a solvent and mixing, polyvinyl acetal resin and poly (ε-caprolactone)
The method of dissolving and mixing in a common solvent is preferable, but the method of dissolving and mixing both in different solvents can also be used without any trouble. As the solvent for dissolving the polyvinyl acetal resin, for example, methanol, ethanol, n-
Alcohols such as propanol, cellsolves such as methylcellosolve, ethylcellosolve and butylcellosolve,
Examples include dioxane, tetrahydrofuran, methylene chloride, chloroform, pyridine, dimethyl sulfoxide, acetic acid and the like. These solvents may be used alone or as a mixture.

A method of dissolving and mixing in a solvent, and a particularly preferable method is to dissolve a polyvinyl acetal resin in a mixed solvent having a volume ratio of ethanol and toluene of 1: 1 to prepare a 10 wt% solution. And poly (ε-caprolactone) dissolved in toluene to form a 10% by weight solution, and mixed,
Then, a method of removing the solvent by evaporation can be mentioned.

When the degree of acetalization of the polyvinyl acetal resin of the present invention 2 is low, it becomes difficult to mold the obtained interlayer film for laminated glass, and when it is high, the compatibility with poly (ε-caprolactone) is high. Since it decreases and the transparency of the laminated glass obtained decreases, it is preferably 50 to 85 mol%, more preferably 60 to 75 mol%. The content of acetyl groups in the polyvinyl acetal resin is not particularly limited, but is 30% by mol% of ethylene groups having acetyl groups bonded to all ethylene groups in the main chain.
It is preferably not more than mol%.

The interlayer film for laminated glass of the present invention 2 is composed of the polyvinyl acetal resin and poly (ε-caprolactone), but poly (ε-caprolactone)
If the content is low, the low-temperature penetration resistance of the laminated glass obtained will decrease, and if the content is high, the high degree of transparency required for the laminated glass obtained will not be satisfied, so 10-40 parts by weight is preferred. .

The interlayer film for laminated glass of the present invention 2 comprises a plasticizer which has been conventionally used, if necessary, an ultraviolet absorber for improving weather resistance, and an antioxidant for improving stability against ultraviolet rays and thermal stability. It is preferable to add an agent.

As a method for producing the interlayer film for laminated glass of the present invention, for example, a polyvinyl acetal resin and poly (ε-caprolactone) are melt-kneaded by using a kneader such as a roll mill, and then, Calendar roll film forming method,
A method of producing by extrusion film formation method or inflation film formation method can be mentioned.

The thickness of the interlayer film for laminated glass of the present invention is
As it becomes thinner, the impact strength of laminated glass decreases, so
Since the transparency of the laminated glass decreases as the thickness increases, 0.1
.About.2.0 mm, more preferably 0.2 to 1.
It is 6 mm.

Using the interlayer film for laminated glass of the present invention,
As a method for producing a laminated glass, a method used for producing a usual laminated glass can be used, for example,
A method of sandwiching an interlayer film for laminated glass between two sheets of glass and heating and pressing with a hot press, or a method of sandwiching an interlayer film for laminated glass between two sheets of glass, placing it in a vacuum bag, degassing, and degassing A method of heating for a certain period of time while maintaining the temperature is mentioned.

When manufacturing the above laminated glass, for example,
Rigid bodies made of inorganic materials other than metal and glass; polycarbonate
It may be laminated with an organic glass such as G .; a polymer film having low rigidity such as a polyester film or a polyurethane film, or paper to form a multilayer type.

Examples of the layer structure of the above-mentioned multilayer laminated glass include (1) glass / intermediate film / polymer film (2) glass / intermediate film / polymer film / intermediate film / glass (3) glass / intermediate film Film / organic glass (4) Glass / intermediate film / metal plate / intermediate film / glass (5) Glass / intermediate film / paper / intermediate film / glass.

[0038]

EXAMPLES Next, examples of the present invention will be described. "Parts" means "parts by weight".

Example 1 (1) Production of polyvinyl acetal resin 2910 parts of pure water was added to a reactor equipped with a stirrer, and the mixture was heated to 90 ° C.
After heating to 190 ° C., 190 parts of highly saponified 99.1 mol% polyvinyl alcohol having an average degree of polymerization of 1700 was added, dissolved and the temperature was adjusted to a constant temperature, and 201 parts of 35 wt% hydrochloric acid and 124 parts of n-butyraldehyde were added. Was added and reacted for a certain period of time to obtain a white powder of polyvinyl acetal resin. The acetyl group bonded to the ethylene group of the obtained resin is 0.9 mol%
The acetalization degree was 66.3 mol%.

(2) Production of polyvinyl acetal resin composition and production of sheet using the same Laboplast mill (manufactured by Toyo Seiki) and poly (ε-caprolactone) (manufactured by Daicel, trade name; PLACCELH
10 parts of 5) are supplied and melt-mixed at 160 ° C. for 2 minutes,
40% of the polyvinyl acetal resin obtained in (1) above
The composition was obtained by adding the mixture in parts by weight and melt mixing for 5 minutes.
The resulting composition is then pressed using a press molding machine 16
The sheet was press-molded at 0 ° C. and 200 kg / cm ² for 20 minutes to obtain a sheet having a thickness of 0.4 mm. Examples 2 to 5 As aldehyde compounds, n-aldehyde was used in Example 2, n-hexylaldehyde was used in Example 3, n-acetaldehyde was used in Example 4, and n-octylaldehyde was used in Example 5. In the same manner as in 1, a polyvinyl acetal resin having the degree of acetalization shown in Table 1 was obtained.

Next, the predetermined amounts of polyvinyl acetal resin and poly (ε-caprolactone) shown in Table 1 were supplied to Labo Plastomill, and a composition and a sheet were produced in the same manner as in Example 1. did.

[0042]

[Table 1]

Comparative Examples 1 to 3 The predetermined amounts of polyvinyl acetal resin and poly (ε-caprolactone) shown in Table 2 were supplied to Laboplast mill, and the composition and sheath were prepared in the same manner as in Example 1. Manufactured.

[0044]

[Table 2]

Comparative Example 4 Comparative Example 4 is an example except that 40 parts of triethylene glycol-di-2-ethylbutyrate is used as a plasticizer instead of poly (ε-caprolactone) in Example 1. A composition and a sheet were produced in the same manner as in 1.

Comparative Example 5 A composition and a sheet were produced in the same manner as in Example 1 except that only poly (ε-caprolactone) was used.

Example 6 (1) Manufacture of interlayer film Laboplast mill (manufactured by Toyo Seiki Co., Ltd.) and poly (ε-caprolactone) (manufactured by Daicel, trade name; PLACCELH)
10 parts of 5) are supplied and melt-mixed at 160 ° C. for 2 minutes,
40 parts by weight of the polyvinyl acetal resin obtained by the method shown in (1) of Example 1 was added, and the mixture was melt-mixed for 5 minutes to obtain a composition. Then, the obtained composition is subjected to 20 at 160 ° C. and 200 kg / cm ² using a press molding machine.
The sheet was press-molded for a minute to obtain a sheet having a thickness of 0.4 mm. (2) Production of laminated glass The sheet produced in (1) above was sandwiched between two sheets of float glass that had been washed and dried in advance and had a thickness of 3 mm. After degassing for 20 minutes, the glass was transferred to an oven while keeping the degassed state and kept at 100 ° C. for 30 minutes to produce a laminated glass. Examples 7 to 10 In Examples 6, 7 and 9 as the aldehyde compound, n-
Butyraldehyde, n-hexyl aldehyde in Example 8 and n-octyl aldehyde in Example 10,
A polyvinyl acetal resin was produced in the same manner as in Example 1 except that the production conditions of Example 1 were changed so that the degree of acetalization shown in Table 3 was obtained. Then, using a Labo Plastomill, polyvinyl acetal resin and poly (ε
-A composition and a sheet were produced in the same manner as in Example 1 except that the amount of (caprolactone) added was changed to the amount shown in Table 3.

[0048]

[Table 3]

A laminated glass was manufactured from the obtained sheet by the same method as in Example 6.

Comparative Examples 6 to 10 In Comparative Examples 6, 9 and 10, n was used as the aldehyde compound.
-Butyl aldehyde, n-hexyl aldehyde in Comparative Example 7 and n-octyl aldehyde in Comparative Example 8 were used in the same manner as in the production of the polyvinyl acetal resin of Example 1 to prepare a polyvinyl acetal resin. Was manufactured. Then, using a Laboplast mill, the input amounts of the polyvinyl acetal resin and poly (ε-caprolactone) into the Laboplast mill were changed so that the number of parts shown in Table 4 was obtained. By the method, a composition and a sheet were produced.

[0051]

[Table 4]

A laminated glass was produced from the obtained sheet by the same method as in Example 6.

Comparative Example 11 Triethylene glycol-di-2-ethylbutyrate was used as a plasticizer in place of the poly (ε-caprolactone) of Example 1 with respect to 100 parts of polyvinyl acetal resin. A composition and a sheet were obtained in the same manner as in Example 1 except that 40 parts were added to a Labo Plastomill.

A laminated glass was manufactured from the obtained sheet by the same method as in Example 6.

Comparative Example 12 A composition and a sheet were produced in the same manner as in Example 1 except that only poly (ε-caprolactone) was used.

A laminated glass was produced from the obtained sheet by the same method as in Example 6.

The sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were subjected to a transparency test, a tensile strength test, a moldability test, a plasticizer migration test and a biodegradability test. The evaluation results are shown in Table 5.

[0058]

[Table 5]

Transparency test Using an integrating turbidimeter (manufactured by Tokyo Denshoku Co., Ltd.), JIS K
671 “Methacrylic resin plate for aircraft”, the total light transmittance and the haze value were measured with a sample having a thickness of 0.4 mm in accordance with the terms of the parallel light transmittance and the haze value.

Tensile Strength Test A maximum load was measured by using a tensile tester under the conditions of 23 ° C. and 50% humidity according to JIS K 7127 “Plastic film and sheet tensile test”.

Plasticizer migration test, polybutyral resin sheet (thickness 0.4 mm) having a degree of acetalization of 66.3 mol%, cut into 10 cm square, and Examples 1 to 5 and Comparative Example 1 Test sheets of the same size are prepared from the sheets obtained in Steps 1 to 5 and are stacked 100 times.
A compressive stress of g / cm ² was applied, the state was maintained at 23 ° C. for 1 month, and then the weight of each sheet was measured to evaluate the transfer amount of the plasticizer.

Moldability test Using a Labo Plastomill, the jacket temperature was set to 160 ° C, the rotation speed of the rotor was set to 30 RPM, and melt mixing was carried out. Those that could be melt-mixed were evaluated as ◯, and those that could not be melt-mixed as the powder were evaluated as x.

Biodegradability test A sheet of 10 cm square and 0.4 mm thick was buried in the compost mixed soil 6 months after digging, and the appearance was visually observed and evaluated according to the following three grades. A: Not decomposed. B: Cracks and holes are observed, and they are slightly disassembled. C: The shape of the sheet is almost unfixed to the extent that residual fragments can be slightly confirmed.

The laminated glasses obtained in Examples 6 to 10 and Comparative Examples 6 to 12 were subjected to a transparency test, an impact resistance test, a plasticizer migration test and a biodegradability test to evaluate the performance. The results are shown in Table 6.

[0065]

[Table 6]

Impact resistance test It was carried out according to JIS R 3205. That is, the laminated glass kept at a temperature of 23 ° C. and a humidity of 50% for 4 hours was vertically held by a supporting frame, and an attacker having a weight of 45 kg and a maximum diameter of 75 mm was dropped from a height of 30 cm to the center of the laminated glass in a pendulum manner. It was The case where an opening through which a sphere having a diameter of 75 mm can freely pass is formed is indicated as x, and the case where it is not formed is indicated as o. The test was performed with n = 4.

[0067]

The specific polyvinyl acetal resin of the present invention is mixed with poly (ε-caprolactone) in a specific amount to obtain mechanical properties such as transparency, adhesiveness with glass, and impact resistance, and molding. A composition having excellent properties can be obtained. Further, since the composition of the present invention does not contain a plasticizer, there is no risk of migration of a low molecular weight plasticizer, and since it contains poly (ε-caprolactone), it is excellent in biodegradability. . Due to such characteristics, it can be used as a transparent molding material such as an interlayer film for laminated glass, ceramics, porcelain tape binder, washer primer, paint, packaging material and the like.

Claims (2)

[Claims] 1. A polyvinyl acetal resin composition comprising 55 to 95 parts by weight of a polyvinyl acetal resin and 45 to 5 parts by weight of poly (ε-caprolactone) represented by the general formula (1). [Chemical 1] 2. An interlayer film for laminated glass, which comprises the polyvinyl acetal resin composition according to claim 1.