Intermediate film for laminated glass and laminated glass

Abstract

The present invention aims to provide an interlayer film for a laminated glass which includes two or more resin layers laminated together and which has excellent deaeration properties in the manufacturing process of a laminated glass and prevents ghosting. The present invention also aims to provide a laminated glass comprising the interlayer film for a laminated glass. The present invention relates to an interlayer film for a laminated glass which includes two or more resin layers laminated together and has many minute recesses and many minute protrusions on at least one surface thereof. The recesses have a groove shape with a continuous bottom. The recesses are formed in a regular manner, and recesses adjacent to each other being parallel. Recesses adjacent to each other are spaced less than 750 m.

Claims

1. An interlayer film for a laminated glass, the interlayer film comprising: a sound insulating layer comprising a polyvinyl acetal X and a plasticizer interposed between two layers of a protective layer comprising a polyvinyl acetal Y and a plasticizer, wherein: the polyvinyl acetal Y comprises a larger amount of hydroxy groups than the polyvinyl acetal X, an amount of the plasticizer in the sound insulating layer based on 100 parts by mass of the polyvinyl acetal X is larger than an amount of the plasticizer in the protective layer based on 100 parts by mass of the polyvinyl acetal Y, the interlayer film having minute recesses and minute protrusions on at least one surface thereof, the recesses each having a groove shape with a continuous bottom, the recesses being formed in a regular manner, recesses adjacent to each other being parallel, recesses adjacent to each other being spaced 100 to 400 m apart, and the recesses have a groove depth (Rzg) determined in accordance with JIS B-0601 (1994) of 10 to 28 m, wherein a laminated glass comprising the interlayer film interposed between two clear glass plates having 2.5 mm thickness gives a single image or a double image with a separation of within 15 minutes of arc when evaluating ghosting in accordance with JIS R 3212 (2008) with a 10 W silica bulb light source or a 40 W silica bulb light source.

2. The interlayer film according to claim 1, wherein the recesses are formed at equal intervals, and recesses adjacent to each other are parallel.

3. The interlayer film according to claim 1, wherein the polyvinyl acetal Y comprises 28 to 33 mol % of hydroxy groups, 60 to 80 mol % of acetal groups and 7 mol % or less of acetyl groups.

4. The interlayer film according to claim 1, wherein the sound insulating layer comprises 45 to 80 parts by mass of the plasticizer based on 100 parts by mass of the polyvinyl acetal X.

5. The interlayer film according to claim 1, wherein the protective layer comprises 20 to 40 parts by mass of the plasticizer based on 100 parts by mass of the polyvinyl acetal Y.

6. The interlayer film according to claim 1, wherein the polyvinyl acetal Y comprises at least 1 mol % more of hydroxy groups than the polyvinyl acetal X.

7. The interlayer film according to claim 1, wherein the amount of the plasticizer in the sound insulating layer based on 100 parts by mass of the polyvinyl acetal X is larger by at least 5 parts by mass than the amount of the plasticizer in the protective layer based on 100 parts by mass of the polyvinyl acetal Y.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic view illustrating an example of an interlayer film for a laminated glass on the surface of which recesses each having a groove shape with a continuous bottom are formed at equal intervals, and recesses adjacent to each other are parallel.

(2) FIG. 2 is a schematic view illustrating an example of an interlayer film for a laminated glass on the surface of which recesses each having a groove shape with a continuous bottom are formed at equal intervals, and recesses adjacent to each other are parallel.

DESCRIPTION OF EMBODIMENTS

(3) The embodiments of the present invention are described in detail below based on, but not limited to, examples.

Example 1

(1) Preparation of Resin Composition for First Resin Layer (Sound Insulating Layer)

(4) Polyvinyl alcohol having an average polymerization degree of 2400 was acetalized with n-butylaldehyde to prepare polyvinyl butyral (acetyl group content: 12 mol %, butyral content: 66 mol %, hydroxy group content: 22 mol %). The polyvinyl butyral (100 parts by mass) was mixed with triethyleneglycol-di-2-ethylhexanoate (3GO) (60 parts by mass) as a plasticizer, and the mixture was sufficiently kneaded with a mixing roll. A resin composition for a first resin layer (sound insulating layer) was thus obtained.

(2) Preparation of Resin Composition for Second Resin Layer (Protective Layer)

(5) Polyvinyl alcohol having an average polymerization degree of 1700 was acetalized with n-butylaldehyde to prepare polyvinyl butyral (acetyl group content: 1 mol %, butyral content: 69 mol %, hydroxy group content: 30 mol %). The polyvinyl butyral (100 parts by mass) was mixed with triethyleneglycol-di-2-ethylhexanoate (3GO) (40 parts by mass) as a plasticizer, and the mixture was sufficiently kneaded with a mixing roll. A resin composition for a second resin layer (protective layer) was thus obtained.

(3) Preparation of Interlayer Film for a Laminated Glass

(6) The resin composition for forming a first resin layer (sound insulating layer) and the resin composition for forming second resin layers (protective layers) were co-extruded with a co-extruder, whereby an interlayer film (thickness: 0.8 mm) for a laminated glass in which the first resin layer (sound insulating layer) was interposed between the two second resin layers (protective layers) was obtained. The first resin layer had a thickness of 0.1 mm. The second resin layers each had a thickness of 0.35 mm.

(4) Formation of Recesses and Protrusions

(7) A pair of rolls including a metal roll having a surface milled with a triangular oblique line-type mill (available from YURIROLL Co., Ltd.) and a rubber roll having a JIS hardness of 45 to 75 was used as a device for transferring the pattern of recesses and protrusions. The obtained interlayer film for a laminated glass was passed through these rolls, whereby recesses and protrusions were formed on one surface (a first surface) of the interlayer film. The recesses each had a groove shape with a continuous bottom and formed parallel to one another at equal intervals. The transfer was carried out under the conditions that the temperature of the interlayer film for a laminated glass was room temperature, the roll temperature was 130 C., the linear velocity was 10 m/min, and the press linear pressure was 500 kPa.

(8) Subsequently, the other surface (a second surface) of the interlayer film for a laminated glass was subjected to the same operation, whereby recesses each having a groove shape with a continuous bottom were formed on the surface.

(9) As for the recesses and protrusions formed on the first surface, the interval between a recess having a groove shape with a continuous bottom and an adjacent one was 200 m, and the recesses had a groove depth (Rzg) of 22 m. As for the recesses and protrusions formed on the second surface, the interval between a recess having a groove shape with a continuous bottom and an adjacent one was 200 m, and the recesses had a groove depth (Rzg) of 18 m.

(10) The recess interval above was determined as follows. The first and second surfaces (viewing range: 20 mm20 mm) of the interlayer film for a laminated glass were each observed with a light microscope (BS-8000III available from SONIC-GROUP), and the interval between each pair of recesses adjacent to each other was determined. On the basis of the obtained values, the average of the shortest distances between the bottommost portions of recesses adjacent to each other was calculated, whereby the recess interval was determined. The average of the shortest distances and the largest thereof were the same.

(11) The groove depth (Rzg) of the recesses herein is the average value of the groove depth determined using the groove depth of observed recesses and the number of the observed recesses. The groove depths of the observed recesses are each calculated based on the average line (a line that is set such that the sum of the squares of the deviations from that line to the roughness curve be minimized) of a roughness curve in accordance with JIS B-0601 (1994) Surface roughnessDefinitions and designation. The groove depth (Rzg) of the recesses was determined by processing digital signals obtained using a surface roughness tester (SE1700 available from Kosaka Laboratory Ltd.).

Examples 2 to 7, Comparative Example 1

(12) Interlayer films for a laminated glass having recesses and protrusions on the surfaces was obtained in the same manner as in Example 1 except that the interval between a recess having a groove shape with a continuous bottom and an adjacent one and the groove depth (Rzg) of the recesses were as listed in Table 1.

(13) The average of the shortest distances and the maximum of the shortest distances, which were determined in the measurement of the recess interval, were the same as each other in each of Examples 2 to 7 and Comparative Example 1.

Example 8

(14) An interlayer film for a laminated glass was obtained in the same manner as in Example 1 except that the amount of triethyleneglycol-di-2-ethylhexanoate (3GO) added in preparation of the resin composition for the first resin layer (sound insulating layer) was 70 parts by mass.

Example 9

(15) An interlayer film for a laminated glass was obtained in the same manner as in Example 2 except that the amount of triethyleneglycol-di-2-ethylhexanoate (3GO) added in preparation of the resin composition for a first resin layer (sound insulating layer) was 70 parts by mass.

Example 10

(16) An interlayer film for a laminated glass was obtained in the same manner as in Example 7 except that the amount of triethyleneglycol-di-2-ethylhexanoate (3GO) added in preparation of the resin composition for the first resin layer (sound insulating layer) was 70 parts by mass.

Example 11

(17) An interlayer film for a laminated glass was obtained in the same manner as in Example 1 except that the polyvinyl butyral used in preparation of the resin composition for the first resin layer (sound insulating layer) was polyvinyl butyral (acetyl group content: 6 mol %, butyral group content: 72 mol %, hydroxy group content: 22 mol %) obtained by acetalizing polyvinyl alcohol having an average polymerization degree of 2400 with n-butylaldehyde.

Example 12

(18) An interlayer film for a laminated glass was obtained in the same manner as in Example 1 except that the polyvinyl butyral used in preparation of the resin composition for the first resin layer (sound insulating layer) was polyvinyl butyral (acetyl group content: 24 mol %, butyral group content: 56 mol %, hydroxy group content: 20 mol %) obtained by acetalizing polyvinyl alcohol having an average polymerization degree of 2400 with n-butylaldehyde.

Example 13

(19) An interlayer film for a laminated glass was obtained in the same manner as in Example 5 except that the polyvinyl butyral used in preparation of the resin composition for the first resin layer (sound insulating layer) was polyvinyl butyral (acetyl group content: 1 mol %, butyral group content: 79 mol %, hydroxy group content: 20 mol %) obtained by acetalizing polyvinyl alcohol having an average polymerization degree of 2400 with n-butylaldehyde.

(20) (Evaluation)

(21) The interlayer films for a laminated glass having recesses and protrusions on the surfaces obtained in the examples and the comparative example were evaluated by the following methods.

(22) The results are shown in Tables 1 and 2.

(23) (1) Evaluation of Deaeration Properties

(24) A laminated glass was produced using the obtained interlayer film for a laminated glass having recesses and protrusions on the surfaces. Specifically, preliminary pressure bonding by a vacuum deaeration method and full pressure bonding were performed as follows.

(25) (Vacuum Deaeration Method)

(26) The interlayer film was interposed between two clear glass plates (length 30 cmwidth 30 cmthickness 2.5 mm). The portions of the film protruding from the plates were cut off. A laminated glass structure (laminate) was thus produced. This structure was transported into a rubber bag, which was then connected to a vacuum suction device. The rubber bag was held under a reduced pressure of 60 kPa (absolute pressure 16 kPa) for 10 minutes with heating so that the temperature (preliminary pressure bonding temperature) of the laminated glass structure (laminate) reached 70 C. Thereafter, the pressure was returned to atmospheric pressure, whereby the preliminary pressure bonding was completed. Here, the deaeration starting temperature in the preliminary pressure bonding was 40 C., 50 C., or 60 C.

(27) (Full Pressure Bonding)

(28) The laminated glass structure (laminate) preliminarily pressure bonded in the above manner was put in an autoclave and held at a temperature of 140 C. at a pressure of 1300 kPa for 10 minutes. Thereafter, the temperature was decreased to 50 C. and the pressure was returned to atmospheric pressure, whereby the full pressure bonding was completed. A laminated glass was thus produced.

(29) (Baking Test of Laminated Glass)

(30) The obtained laminated glass was heated in an oven at 140 C. for 2 hours. Thereafter, the laminated glass was taken out of the oven and allowed to cool for 3 hours. The appearance of the cooled laminated glass was visually observed. Twenty sheets of the laminated glass were tested, and the number of sheets in which foam (air bubbles) were formed was determined. The deaeration properties were evaluated based on the number.

(31) (2) Evaluation of Ghosting

(32) The laminated glass was evaluated for the presence of ghosting using two light sources having different intensities, a light source 1 and a light source 2. The light source 1 was a 10 W silica bulb (available from Kyokko Electric Co., Ltd., PS55 E26 110V-10W, total flux: 70 lm) to simulate a light source of a typical intensity which can be incident on window glass of automobiles, aircraft, architectures, or the like. The light source 2 was a 40 W silica bulb (available from ASAHI ELECTRIC Co., Ltd., LW100V38W-W, total flux: 440 lm) to simulate a light source which particularly had a high intensity among lights which can be incident on window glass of automobiles, aircraft, architectures or the like.

(33) The evaluation was carried out in accordance with JIS R 3212 (2008). A laminated glass was evaluated as excellent (oo) if it gave, whether using the light source 1 or the light source 2, a single image or a double image with a separation of within 15 minutes of arc. It was evaluated as good (O) if it gave ghost images using the light source 2 but gave a single image or a double image with a separation of within 15 minutes of arc using the light source 1. It was evaluated as poor (x) if it gave ghost images whether using the light source 1 or the light source 2.

(34) The mounting angle to the actual vehicle was 30. The double image with a separation of within 15 minutes of arc was due to the glass, not the interlayer film.

(35) TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 1 Recess interval First surface 200 180 500 600 200 180 400 750 (m) Second surface 200 180 500 600 200 180 400 750 Groove depth First surface 22 22 21 20 28 27 20 25 of recesses Second surface 18 17 20 21 26 22 20 24 (Rzg) (m) Evaluation of Deaeration 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 deaeration starting properties temperature/ C. Preliminary 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 pressure bonding temperature/ C. Baking test 0 1 1 0 1 1 0 0 0 0 0 0 0 1 2 0 2 2 0 0 1 0 0 0 (Number of sheets in which foaming occured/ 20 sheets) Evaluation of ghosting X

(36) TABLE-US-00002 TABLE 2 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Recess interval First surface 200 180 400 200 200 200 (m) Second surface 200 180 400 200 200 200 Groove depth of recesses First surface 22 22 20 22 22 28 (Rzg) (m) Second surface 18 17 20 18 18 26 Evaluation of deaeration Deaeration starting 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 40 50 60 properties temperature/ C. Preliminary pressure 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 bonding temperature/ C. Baking test 0 1 2 1 1 1 0 1 1 0 1 1 0 1 2 0 1 1 (Number of sheets in which foaming occured/20 sheets) Evaluation of ghosting

INDUSTRIAL APPLICABILITY

(37) The present invention provides an interlayer film for a laminated glass including two or more resin layers laminated together. The interlayer film has excellent deaeration properties in the manufacturing process of a laminated glass and prevents ghosting. The present invention also provides a laminated glass comprising the interlayer film for a laminated glass.