JP6770818B2 - Laminated glass interlayer film - Google Patents

Description

INDUSTRIAL APPLICABILITY According to the present invention, a laminated glass interlayer film capable of exhibiting high degassing property by the nip roll method and capable of producing a laminated glass having high visibility without generating bubbles, and a laminated glass using the laminated glass interlayer film. I will provide a.

Laminated glass obtained by sandwiching an interlayer film for laminated glass containing a thermoplastic resin such as plasticized polyvinyl butyral between two glass plates and adhering them to each other is widely used as a windshield for automobiles.

As one of the methods for manufacturing such an automobile windshield, a vacuum degassing method is performed.
In the vacuum degassing method, a laminated body in which a laminated glass interlayer film is laminated between at least two glass plates is placed in a rubber bag and sucked under reduced pressure to degas the air remaining between the glass plates and the interlayer film. While pre-crimping, the windshield for automobiles is obtained by, for example, heating and pressurizing in an autoclave to perform main crimping.

In the manufacturing process of laminated glass by the vacuum degassing method, degassing property when laminating the glass and the interlayer film for laminated glass is important. Therefore, fine irregularities are formed on at least one surface of the interlayer film for laminated glass for the purpose of ensuring degassing property during the production of laminated glass. In particular, it is extremely excellent by forming the recesses in the unevenness into a structure in which the bottom has a continuous groove shape (engraved line shape) and the adjacent engraved linear recesses are regularly formed in parallel. Degassing properties can be exhibited (for example, Patent Document 1).

On the other hand, as a method for manufacturing laminated glass, there is a nip roll method. In the nip roll method, a laminated body in which a laminated glass interlayer film is laminated between at least two glass plates is conveyed by a conveyor, and the laminated body is heated to a constant temperature by passing through a heating zone. After that, the air remaining between the glass and the interlayer film is removed while being handled through the nip roll, and at the same time, thermocompression bonding is performed to reduce the air between the interlayer film and the glass of the laminated body and bring them into close contact with each other.

However, there is a problem that the degassing property of the obtained laminated glass may be lowered when the laminated glass is manufactured by the nip roll method using the laminated glass interlayer film used for manufacturing the laminated glass by the vacuum degassing method. was there.

Japanese Unexamined Patent Publication No. 2001-48599

The present inventors have studied the cause of the decrease in the degassing property of the obtained laminated glass when the laminated glass is produced by the nip roll method. As a result, it was found that the cause was a groove-shaped concave portion (hereinafter, also referred to as "engraved linear concave portion") formed on the surface of the laminated glass interlayer film for degassing. In the vacuum degassing method, since decompression and heating are performed at the same time and pre-crimping is performed, the air inside the engraved concave portion is removed by decompression, so that the concave portion remains without being crushed in the obtained laminated glass. That was rarely a problem. However, in the nip roll method, since the film and the glass are crimped only by pressure during the pre-crimping, the recesses may remain without being crushed after the pre-crimping. If the amount of air remaining in the recesses remaining without being crushed is large, air bubbles may remain in the film even after pressure heating and crimping in an autoclave, resulting in deterioration of visibility. Further, especially when the temperature of the laminated glass precursor at the time of pre-crimping is low, the recesses are hard to be crushed and bubbles are likely to remain.

INDUSTRIAL APPLICABILITY According to the present invention, a laminated glass interlayer film capable of exhibiting high degassing property by the nip roll method and capable of producing a laminated glass having high visibility without generating bubbles, and a laminated glass using the laminated glass interlayer film. The purpose is to provide. The laminated glass interlayer film according to the present invention may be used not only in the nip roll method but also in the vacuum degassing method.

The present invention has a large number of concave portions and a large number of convex portions on at least one surface, the concave portions have a groove shape with a continuous bottom portion, and the adjacent concave portions are regularly arranged in parallel. The ratio (R / Sm × 100) of the radius of gyration R of the bottom of the groove-shaped recess having a continuous bottom to the distance Sm of the groove-shaped recess having a continuous bottom is 15 in the laminated glass interlayer film. % Or more, and the interlayer film for laminated glass having one end and the other end on the opposite side of the one end, and the thickness of the other end is larger than the thickness of the one end.
In the present invention, "having a large number of concave portions and a large number of convex portions on at least one surface" means "a large number of concave portions and a large number of convex portions are formed on at least one surface". It also means that "the recess has a groove shape with a continuous bottom, and the adjacent recesses are parallel and regularly parallel" means that "the recess has a groove shape with a continuous bottom." However, it also means that the adjacent recesses are regularly formed in parallel. "
The present invention will be described in detail below.

As a result of diligent studies, the present inventors can exhibit high degassing properties even by the nip roll method by specifying the uneven shape of the interlayer film for laminated glass, and manufacture laminated glass with high visibility. We found what we could do and completed the present invention. The laminated glass interlayer film according to the present invention may be used not only in the nip roll method but also in the vacuum degassing method.

The interlayer film for laminated glass of the present invention has a large number of concave portions and a large number of convex portions on at least one surface, and the concave portions have a groove shape with a continuous bottom portion and the adjacent concave portions are parallel to each other. Are regularly parallel. Thereby, the degassing property at the time of manufacturing the laminated glass by the nip roll method can be ensured. The unevenness may be provided only on one surface, but it is preferably provided on both sides of the interlayer film for laminated glass because the degassing property is significantly improved.

In the interlayer film for laminated glass of the present invention, the concave-convex recesses on at least one of the surfaces have a continuous groove shape at the bottom (that is, have "engraved linear recesses"), and adjacent recesses. Are parallel and regularly parallel. In general, the ease with which air can escape when crimping a laminate in which a laminated glass interlayer film is laminated between two glass plates is closely related to the communication and smoothness of the bottom of the recess. By forming the uneven shape of at least one surface of the interlayer film into a shape in which the engraved concave portions are parallel and regularly arranged, the communication of the bottom portion is excellent and the degassing property is remarkably improved.
In addition, "regularly parallel" may mean that the adjacent engraved concave portions are parallel and parallel at equal intervals, and the adjacent engraved concave portions are parallel and parallel. However, it means that the distance between all the adjacent carved linear recesses does not have to be equal. Further, the recess on the engraved line does not have to have a continuous groove shape at the bottom, and may have a dividing wall at a part of the bottom. Further, as long as the adjacent recesses are parallel and regularly arranged, the shape of the groove at the bottom does not have to be linear, and may be, for example, a wavy shape or a zigzag shape.

In the interlayer film for laminated glass of the present invention, the ratio (R / Sm × 100) of the radius of gyration R of the bottom of the groove-shaped recess having a continuous bottom to the distance Sm of the groove-shaped recess having a continuous bottom is 15. % Or more. As a result, when laminated glass is manufactured by the nip roll method, sufficient degassing properties can be exhibited during pre-crimping, and the engraved recesses can be crushed by the pressure during pre-crimping, preventing air from remaining. However, a transparent laminated glass without air bubbles can be obtained.
The ratio (R / Sm × 100) of the radius of gyration R of the bottom of the groove-shaped recess having a continuous bottom to the distance Sm of the groove-shaped recess having a continuous bottom is preferably 20% or more, preferably 30% or more. Is more preferable, and more preferably 50% or more. The ratio (R / Sm × 100) of the radius of gyration R of the bottom of the groove-shaped recess having a continuous bottom to the distance Sm of the groove-shaped recess having a continuous bottom is preferably 200% or less. More preferably, it is 100% or less.

In the present specification, the radius of gyration R at the bottom of the engraved recess is set in the direction of the engraved recess using a single-edged razor (for example, Feather Safety razor, FAS-10) for the laminated glass interlayer film. On the other hand, the razor is cut by pushing it in the direction parallel to the thickness direction without sliding the razor in the direction perpendicular to the recess so as not to deform the cut surface in the vertical direction and parallel to the film thickness direction, and the cross section is microscopic. Observe using a scope (for example, "DSX-100" manufactured by Olympus), shoot at a measurement magnification of 208 times, and magnify the shot image to 50 μm / 20 mm in the attached software. It can be obtained by a method in which the radius of the circle when an inscribed circle is drawn at the bottom of the engraved concave portion is defined as the radius of gyration R of the concave portion by using the measurement software of. The environment at the time of measurement is 23 ° C. and 30 RH% below. Here, any 5 points in the interlayer film are taken as samples, R is measured at 3 points for each sample, and the average value of a total of 15 points is taken as R.
Further, the spacing Sm of the engraved concave portions in the present specification is defined in JIS B-0601 (1994). For the spacing Sm of the engraved concave portions, observe the first surface and the second surface (observation range 20 mm × 20 mm) of the interlayer film for laminated glass using an optical microscope (“BS-D8000III” manufactured by SONIC). , It is obtained by measuring the distance between adjacent recesses and then calculating the average value of the shortest distances between the bottoms of the adjacent recesses.

The preferred lower limit of the radius of gyration R at the bottom of the engraved concave portion is 20 μm, and the preferred upper limit is 250 μm. When the radius of gyration R of the bottom of the engraved concave portion is within this range, it is easier to crush the engraved concave portion by the pressure at the time of pre-crimping when the laminated glass is manufactured by the nip roll method. , Demonstrates better degassing properties. The more preferable lower limit of the turning radius R of the bottom of the engraved concave portion is 40 μm, and the more preferable upper limit is 125 μm.

The preferable lower limit of the interval Sm of the engraved concave portions is 50 μm, and the preferable upper limit is 1000 μm. When the interval Sm of the engraved recesses is within this range, when laminated glass is manufactured by the nip roll method, better degassing property is exhibited at the time of pre-crimping, and the engraved recesses due to the pressure. It becomes easier to crush. The more preferable lower limit of the interval Sm of the engraved line-shaped recesses is 100 μm, the more preferable lower limit is 175 μm, the more preferable upper limit is 400 μm, and the further preferable upper limit is 300 μm. By setting the interval between the engraved concave portions to be equal to or greater than the above lower limit, good degassing property can be obtained even in the vacuum back method.

The preferable lower limit of the roughness (Rz) of the engraved concave portion is 10 μm, and the preferable upper limit is 80 μm. By setting the roughness (Rz) of the engraved concave portion within this range, excellent degassing property can be exhibited. The more preferable lower limit of the roughness (Rz) of the engraved concave portion is 20 μm, and the more preferable upper limit is 65 μm. A more preferable upper limit is 50 μm.
In this specification, the roughness (Rz) of the engraved concave portion is defined in JIS B-0601 (1994), and is measured in the vertical direction so that the concave portion in the engraved direction crosses the continuous direction. Obtained by doing. Here, as the measuring machine, for example, "Surfcorder SE300" manufactured by Kosaka Laboratory Co., Ltd. can be used, the cutoff value at the time of measurement is 2.5 mm, the reference length is 2.5 mm, and the measurement length is 12.5 mm. The preliminary length is 2.5 mm, the feeding speed of the tactile needle is 0.5 mm / sec, the shape of the stylus is 2 μm at the tip radius, and the tip angle is 60 °. The environment at the time of measurement is 23 ° C. and 30 RH% below. The interlayer film to be measured is measured after being allowed to stand for 3 hours or more in the environment at the time of measurement.

In the interlayer film for laminated glass of the present invention, the preferable lower limit of the radius of gyration R'at the tip of the convex portion of the unevenness is 15 μm. As a result, the frictional force between the glass and the laminated glass interlayer is increased, and it is more effective to prevent the glass and the laminated glass interlayer from being displaced on the conveyor when the laminated glass is manufactured by the nip roll method. Can be prevented. The upper limit of the radius of gyration R'at the tip of the convex portion is not particularly limited, but is preferably 100 μm or less. As a result, even when the interlayer films are laminated, the films do not adhere to each other, and the handleability is improved. The more preferable lower limit of the turning radius R'at the tip of the convex portion is 30 μm, and the more preferable upper limit is 80 μm.
The radius of gyration R'at the tip of the convex portion is obtained by cutting the interlayer film in the direction perpendicular to the direction of the engraved concave portion and in the film thickness direction, and cutting the cross section with a microscope (for example, manufactured by Olympus Corporation). Observe using "DSX-100"), shoot at a measurement magnification of 555 times, and in a state where the shot image is enlarged and displayed so as to be 50 μ / 20 mm, use the measurement software in the attached software. It can be obtained by a method in which the radius of the circle when a circle inscribed in the apex of the convex shape is drawn is the radius of gyration of the tip of the convex portion. The environment at the time of measurement is 23 ° C. and 30 RH% below.

The interlayer film for laminated glass of the present invention preferably contains a thermoplastic resin.
Examples of the thermoplastic resin include polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-propylene hexafluoride copolymer, polyethylene trifluoride, acrylonitrile-butadiene-styrene copolymer, polyester, polyether, and polyamide. , Polycarbonate, polyacrylate, polymethacrylate, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyvinyl acetal, ethylene-vinyl acetate copolymer and the like. Of these, polyvinyl acetal or ethylene-vinyl acetate copolymer is preferable, and polyvinyl acetal is more preferable.

The polyvinyl acetal can be produced, for example, by acetalizing polyvinyl alcohol (PVA) with an aldehyde. The polyvinyl acetal is preferably an acetal product of polyvinyl alcohol. The degree of saponification of PVA is generally in the range of 70-99.9 mol%.

The degree of polymerization of PVA for obtaining the polyvinyl acetal is preferably 200 or more, more preferably 500 or more, still more preferably 1700 or more, particularly preferably 2000 or more, preferably 5000 or less, more preferably 4000 or less, and even more preferably. Is 3000 or less, more preferably less than 3000, and particularly preferably 2800 or less. The polyvinyl acetal is preferably a polyvinyl acetal obtained by acetalizing PVA having a degree of polymerization of more than the above lower limit and not more than the above upper limit. When the degree of polymerization is at least the above lower limit, the penetration resistance of the laminated glass is further increased. When the degree of polymerization is not more than the above upper limit, molding of the interlayer film becomes easy.

The degree of polymerization of PVA indicates the average degree of polymerization. The average degree of polymerization is determined by a method based on JIS K6726 "polyvinyl alcohol test method". As the aldehyde, generally, an aldehyde having 1 to 10 carbon atoms is preferably used. Examples of the aldehyde having 1 to 10 carbon atoms include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutylaldehyde, n-barrelaldehyde, 2-ethylbutylaldehyde, n-hexylaldehyde, and n-octylaldehyde. Examples thereof include n-nonylaldehyde, n-decylaldehyde and benzaldehyde. Of these, n-butyraldehyde, n-hexylaldehyde or n-bareraldehyde are preferable, and n-butyraldehyde is more preferable. Only one kind of the above aldehyde may be used, or two or more kinds may be used in combination.

The polyvinyl acetal is preferably polyvinyl butyral. By using polyvinyl butyral, the weather resistance of the interlayer film to the laminated glass member is further improved.

The interlayer film for laminated glass of the present invention preferably contains a plasticizer.
The plasticizer is not particularly limited as long as it is a plasticizer generally used for an interlayer film for laminated glass, and for example, an organic plasticizer such as a monobasic organic acid ester or a polybasic organic acid ester, or an organic plasticizer. Examples thereof include phosphoric acid plasticizers such as phosphoric acid compounds and organic phosphite compounds.
Examples of the organic plasticizer include triethylene glycol-di-2-ethylhexanoate, triethylene glycol-di-2-ethylbutyrate, triethylene glycol-di-n-heptanoate, and tetraethylene glycol-di-2. -Ethylene hexanoate, tetraethylene glycol-di-2-ethylbutyrate, tetraethylene glycol-di-n-heptanoate, diethylene glycol-di-2-ethylhexanoate, diethylene glycol-di-2-ethylbutyrate, diethylene glycol -Di-n-heptanoate and the like can be mentioned. Among them, triethylene glycol-di-2-ethylhexanoate, triethylene glycol-di-2-ethylbutyrate, or triethylene glycol-di-n-heptanoate is preferably contained, and triethylene glycol-di More preferably, it contains -2-ethylhexanoate.

The interlayer film for laminated glass of the present invention preferably contains an adhesive force adjusting agent.
As the adhesive force regulator, for example, an alkali metal salt or an alkaline earth metal salt is preferably used. Examples of the adhesive strength adjusting agent include salts of potassium, sodium, magnesium and the like.
Examples of the acid constituting the salt include organic acids of carboxylic acids such as octyl acid, hexic acid, 2-ethylbutyric acid, butyric acid, acetic acid and formic acid, and inorganic acids such as hydrochloric acid and nitric acid.

The interlayer film for laminated glass of the present invention is, if necessary, an antioxidant, a light stabilizer, a modified silicone oil as an adhesive strength adjusting agent, a flame retardant, an antistatic agent, a moisture resistant agent, a heat ray reflecting agent, a heat ray absorbing agent, etc. May contain the additive of.

The interlayer film for laminated glass of the present invention has one end and the other end on the opposite side of the one end. The one end and the other end are both end portions facing each other in the interlayer film. In the interlayer film for laminated glass of the present invention, the thickness of the other end is larger than the thickness of the one end. By having such a shape in which the thicknesses of one end and the other end are different, the double image can be effectively suppressed when the laminated glass using the interlayer film for laminated glass of the present invention is used as a head-up display.

The interlayer film for laminated glass of the present invention preferably has a glossiness of 35% or less.
In the present specification, the glossiness means a 75-degree mirror gloss measured in accordance with JIS Z 8741: 1997 using a precision gloss meter (for example, "GM-26PRO" manufactured by Murakami Color Research Institute). .. The interlayer film having a glossiness of 35% or less has a fine uneven shape, suppresses the self-adhesive force when the films are laminated, and can improve the handleability. A more preferable upper limit of the glossiness is 20% or less, and a more preferable upper limit is 10% or less. When the glossiness is 3% or more, it is possible to prevent fine uneven shapes from remaining between the film and the glass during preliminary crimping, and to prevent air bubbles from remaining in the film even after pressure heating crimping with an autoclave. be able to.

When the interlayer film for laminated glass of the present invention has a multilayer structure, for example, in order to improve the sound insulation of the laminated glass, the first resin layer is used as a protective layer and the second resin layer is used as a sound insulating layer. Examples thereof include an interlayer film for laminated glass having excellent sound insulation properties (hereinafter, also referred to as “sound insulation interlayer film”) in which a sound insulation layer is sandwiched between two protective layers.
Hereinafter, the sound insulation interlayer film will be described more specifically.

In the sound insulation interlayer film, the sound insulation layer has a role of imparting sound insulation.
The sound insulation layer preferably contains polyvinyl acetal X and a plasticizer.
The polyvinyl acetal X can be prepared by acetalizing polyvinyl alcohol with an aldehyde. The polyvinyl acetal X is preferably an acetal product of polyvinyl alcohol. The polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate.
The preferable lower limit of the degree of polymerization of the polyvinyl alcohol is 200, and the preferable upper limit is 5000. By setting the degree of polymerization of the polyvinyl alcohol to 200 or more, the penetration resistance of the obtained sound insulation interlayer film can be improved, and by setting the degree of polymerization to 5000 or less, the moldability of the sound insulation layer can be ensured. The more preferable lower limit of the degree of polymerization of the polyvinyl alcohol is 500, and the more preferable upper limit is 4000.

The preferable lower limit of the carbon number of the aldehyde for acetalizing the polyvinyl alcohol is 4, and the preferable upper limit is 6. By setting the number of carbon atoms of the aldehyde to 4 or more, a sufficient amount of plasticizer can be stably contained, and excellent sound insulation performance can be exhibited. In addition, bleeding out of the plasticizer can be prevented. By setting the carbon number of the aldehyde to 6 or less, the synthesis of polyvinyl acetal X can be facilitated and the productivity can be ensured.
The aldehyde having 4 to 6 carbon atoms may be a linear aldehyde or a branched aldehyde, and examples thereof include n-butyraldehyde and n-valeraldehyde. ..

The preferable upper limit of the amount of hydroxyl groups of the polyvinyl acetal X is 30 mol%. By setting the amount of hydroxyl groups of the polyvinyl acetal X to 30 mol% or less, an amount of plasticizer necessary for exhibiting sound insulation can be contained, and bleed-out of the plasticizer can be prevented. The more preferable upper limit of the amount of hydroxyl groups of the polyvinyl acetal X is 28 mol%, the more preferable upper limit is 26 mol%, the particularly preferable upper limit is 24 mol%, the preferable lower limit is 10 mol%, the more preferable lower limit is 15 mol%, and the further preferable lower limit. Is 20 mol%.
The amount of hydroxyl groups of the polyvinyl acetal X is a value expressed as a percentage (mol%) of the molar fraction obtained by dividing the amount of ethylene groups to which the hydroxyl groups are bonded by the total amount of ethylene groups in the main chain. The amount of ethylene groups to which the hydroxyl groups are bonded can be determined, for example, by measuring the amount of ethylene groups to which the hydroxyl groups of the polyvinyl acetal X are bonded by a method based on JIS K6728 "Polyvinyl Butyral Test Method". it can.

The preferable lower limit of the acetal group amount of the polyvinyl acetal X is 60 mol%, and the preferable upper limit is 85 mol%. By setting the acetal group amount of the polyvinyl acetal X to 60 mol% or more, the hydrophobicity of the sound insulation layer can be increased, and an amount of plasticizer necessary for exhibiting sound insulation can be contained. Bleedout and whitening can be prevented. By setting the acetal group amount of the polyvinyl acetal X to 85 mol% or less, the synthesis of the polyvinyl acetal X can be facilitated and the productivity can be ensured. The acetal group amount can be determined by measuring the amount of the ethylene group to which the acetal group of the polyvinyl acetal X is bonded by a method based on JIS K6728 "polyvinyl butyral test method".

The preferable lower limit of the acetyl group amount of the polyvinyl acetal X is 0.1 mol%, and the preferable upper limit is 30 mol%. By setting the amount of the acetyl group of the polyvinyl acetal X to 0.1 mol% or more, an amount of plasticizer necessary for exhibiting sound insulation can be contained, and bleed-out can be prevented. Further, by setting the amount of the acetyl group of the polyvinyl acetal X to 30 mol% or less, the hydrophobicity of the sound insulation layer can be increased and whitening can be prevented. The more preferable lower limit of the amount of acetyl groups is 1 mol%, the further preferable lower limit is 5 mol%, the particularly preferable lower limit is 8 mol%, the more preferable upper limit is 25 mol%, and the further preferable upper limit is 20 mol%. The acetyl group amount is the total ethylene group amount of the main chain obtained by subtracting the ethylene group amount to which the acetal group is bonded and the ethylene group amount to which the hydroxyl group is bonded from the total ethylene group amount of the main chain. It is a value expressed as a percentage (mol%) of the molar fraction obtained by dividing by.

In particular, since the sound insulation layer can easily contain an amount of a plasticizing agent necessary for exhibiting sound insulation, the polyvinyl acetal X is a polyvinyl acetal having an acetyl group content of 8 mol% or more, or It is preferable that the polyvinyl acetal has an acetyl group content of less than 8 mol% and an acetal group content of 68 mol% or more.

The content of the plasticizer in the sound insulation layer is such that the preferable lower limit is 45 parts by mass and the preferable upper limit is 80 parts by mass with respect to 100 parts by mass of the polyvinyl acetal X. When the content of the plasticizer is 45 parts by mass or more, high sound insulation can be exhibited, and when it is 80 parts by mass or less, the plasticizer bleeds out and the interlayer film for laminated glass is formed. It is possible to prevent deterioration of transparency and adhesiveness. The more preferable lower limit of the content of the plasticizer is 50 parts by mass, the more preferable lower limit is 55 parts by mass, the more preferable upper limit is 75 parts by mass, and the further preferable upper limit is 70 parts by mass. The content of the plasticizer in the sound insulation layer may be the plasticizer content before the laminated glass is produced, or may be the plasticizer content after the laminated glass is produced. The content of the plasticizer after the laminated glass is produced can be measured according to the following procedure. After preparing the laminated glass, it is allowed to stand for 4 weeks in an environment of a temperature of 25 ° C. and a humidity of 30%. Then, the laminated glass is cooled with liquid nitrogen to peel off the glass and the interlayer film for laminated glass. The obtained protective layer and sound insulation layer are cut in the thickness direction and allowed to stand in an environment of a temperature of 25 ° C. and a humidity of 30% for 2 hours, and then a finger or a machine is inserted between the protective layer and the sound insulation layer. Peel off in an environment of a temperature of 25 ° C. and a humidity of 30% to obtain a rectangular measurement sample of 10 g for each of the protective layer and the sound insulation layer. For the measurement sample, the plasticizer is extracted with diethyl ether for 12 hours using a Soxhlet extractor, and then the plasticizer in the measurement sample is quantified to determine the content of the plasticizer in the protective layer and the intermediate layer.

The interlayer film for laminated glass of the present invention may have one end of the laminated glass as a whole and the other end on the opposite side of the one end, and the thickness of the other end may be larger than the thickness of the one end. The thickness of the sound insulation layer may be uniform or different over the entire sound insulation layer. The sound insulation layer may have one end and the other end on the opposite side of the one end, and the thickness of the other end may be larger than the thickness of the one end. The sound insulation layer preferably has a portion having a wedge-shaped cross-sectional shape in the thickness direction. The preferable lower limit of the minimum thickness of the sound insulation layer is 50 μm. By setting the minimum thickness of the sound insulation layer to 50 μm or more, sufficient sound insulation can be exhibited. A more preferable lower limit of the minimum thickness of the sound insulation layer is 80 μm, and a further preferable lower limit is 100 μm. The upper limit of the maximum thickness of the sound insulation layer is not particularly limited, but the upper limit is preferably 300 μm in consideration of the thickness of the interlayer film for laminated glass. A more preferable upper limit of the maximum thickness of the sound insulation layer is 220 μm.

The protective layer prevents a large amount of plasticizer contained in the sound insulating layer from bleeding out to reduce the adhesiveness between the laminated glass interlayer film and the glass, and also has penetration resistance to the laminated glass interlayer film. Has the role of granting.
The protective layer preferably contains, for example, polyvinyl acetal Y and a plasticizer, and more preferably contains polyvinyl acetal Y and a plasticizer having a larger amount of hydroxyl groups than polyvinyl acetal X.

The polyvinyl acetal Y can be prepared by acetalizing polyvinyl alcohol with an aldehyde. The polyvinyl acetal Y is preferably an acetal product of polyvinyl alcohol.
The polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate. The preferable lower limit of the degree of polymerization of the polyvinyl alcohol is 200, and the preferable upper limit is 5000. By setting the degree of polymerization of the polyvinyl alcohol to 200 or more, the penetration resistance of the interlayer film for laminated glass can be improved, and by setting the degree of polymerization to 5000 or less, the moldability of the protective layer can be ensured. The more preferable lower limit of the degree of polymerization of the polyvinyl alcohol is 500, and the more preferable upper limit is 4000.

The preferable lower limit of the carbon number of the aldehyde for acetalizing the polyvinyl alcohol is 3, and the preferable upper limit is 4. By setting the number of carbon atoms of the aldehyde to 3 or more, the penetration resistance of the interlayer film for laminated glass is increased. By setting the number of carbon atoms of the aldehyde to 4 or less, the productivity of polyvinyl acetal Y is improved.
The aldehyde having 3 to 4 carbon atoms may be a linear aldehyde or a branched aldehyde, and examples thereof include n-butyraldehyde and the like.

The preferable upper limit of the amount of hydroxyl groups of the polyvinyl acetal Y is 33 mol%, and the preferable lower limit is 28 mol%. By setting the amount of hydroxyl groups of the polyvinyl acetal Y to 33 mol% or less, whitening of the interlayer film for laminated glass can be prevented. By setting the amount of hydroxyl groups of the polyvinyl acetal Y to 28 mol% or more, the penetration resistance of the interlayer film for laminated glass is increased.

In the polyvinyl acetal Y, the preferable lower limit of the acetal group amount is 60 mol%, and the preferable upper limit is 80 mol%. By setting the amount of the acetal group to 60 mol% or more, it is possible to contain an amount of plasticizer necessary for exhibiting sufficient penetration resistance. By setting the amount of the acetal group to 80 mol% or less, the adhesive force between the protective layer and the glass can be ensured. The more preferable lower limit of the acetal group amount is 65 mol%, and the more preferable upper limit is 69 mol%.

The preferable upper limit of the acetyl group amount of the polyvinyl acetal Y is 7 mol%. By setting the amount of the acetyl group of the polyvinyl acetal Y to 7 mol% or less, the hydrophobicity of the protective layer can be increased and whitening can be prevented. The more preferable upper limit of the amount of the acetyl group is 2 mol%, and the preferable lower limit is 0.1 mol%. The amount of hydroxyl groups, the amount of acetal groups, and the amount of acetyl groups of polyvinyl acetal Y can be measured by the same method as for polyvinyl acetal X.

Regarding the content of the plasticizer in the protective layer, the preferable lower limit is 20 parts by mass and the preferable upper limit is 45 parts by mass with respect to 100 parts by mass of the polyvinyl acetal Y. By setting the content of the plasticizer to 20 parts by mass or more, penetration resistance can be ensured, and by setting the content to 45 parts by mass or less, bleed-out of the plasticizer is prevented and an interlayer film for laminated glass is prevented. It is possible to prevent deterioration of transparency and adhesiveness of the glass. The more preferable lower limit of the content of the plasticizer is 30 parts by mass, the more preferable lower limit is 35 parts by mass, the more preferable upper limit is 43 parts by mass, and the further preferable upper limit is 41 parts by mass. The content of the plasticizer in the protective layer is preferably smaller than the content of the plasticizer in the sound insulation layer, because the sound insulation of the laminated glass is further improved. The content of the plasticizer in the protective layer may be the plasticizer content before the laminated glass is produced, or may be the plasticizer content after the laminated glass is produced. The content of the plasticizer after the laminated glass is produced can be measured by the same procedure as that for the sound insulation layer.

Since the sound insulation of the laminated glass is further improved, the amount of hydroxyl groups of polyvinyl acetal Y is preferably larger than the amount of hydroxyl groups of polyvinyl acetal X, more preferably 1 mol% or more, and further 5 mol% or more. It is preferable, and it is particularly preferable that it is larger than 8 mol%. By adjusting the amounts of hydroxyl groups of polyvinyl acetal X and polyvinyl acetal Y, the content of the plasticizer in the sound insulation layer and the protective layer can be controlled, and the glass transition temperature of the sound insulation layer becomes low. As a result, the sound insulation of the laminated glass is further improved.
Further, since the sound insulation of the laminated glass is further improved, the content of the plasticizer (hereinafter, also referred to as the content X) with respect to 100 parts by mass of the polyvinyl acetal X in the sound insulation layer is the polyvinyl acetal Y100 in the protective layer. It is preferably larger than the content of the plasticizer (hereinafter, also referred to as content Y) with respect to parts by mass, more preferably 5 parts by mass or more, further preferably 15 parts by mass or more, and 20 parts by mass or more. Is particularly preferred. By adjusting the content X and the content Y, the glass transition temperature of the sound insulation layer is lowered. As a result, the sound insulation of the laminated glass is further improved.

The interlayer film for laminated glass of the present invention may have one end of the laminated glass as a whole and the other end on the opposite side of the one end, and the thickness of the other end may be larger than the thickness of the one end. The thickness of the protective layer may be uniform or different over the entire protective layer. The protective layer may have one end and the other end on the opposite side of the one end, and the thickness of the other end may be larger than the thickness of the one end. The protective layer preferably has a portion having a wedge-shaped cross-sectional shape in the thickness direction.
The thickness of the protective layer may be adjusted within a range in which the protective layer can play a role, and is not particularly limited. However, when the protective layer has irregularities, it is preferable to make the protective layer as thick as possible so that the transfer of the irregularities to the interface with the sound insulation layer in direct contact can be suppressed. Specifically, the preferable lower limit of the minimum thickness of the protective layer is 100 μm, the more preferable lower limit is 300 μm, the further preferable lower limit is 400 μm, and the particularly preferable lower limit is 450 μm. The upper limit of the maximum thickness of the protective layer is not particularly limited, but in order to secure the thickness of the sound insulation layer to the extent that sufficient sound insulation can be achieved, the upper limit is substantially 1000 μm, preferably 800 μm. ..

The laminated glass interlayer film of the present invention preferably has a portion having a wedge-shaped cross-sectional shape in the thickness direction as the entire laminated glass interlayer film. Since the cross-sectional shape of the entire laminated glass interlayer film in the thickness direction is wedge-shaped, it is effective to generate a double image when the laminated glass using the laminated glass interlayer film of the present invention is used as a head-up display. Can be prevented. When the cross-sectional shape in the thickness direction has a wedge-shaped portion, the wedge angle θ of the entire interlayer film for laminated glass is preferably 0.01 mrad or more because the generation of double images can be effectively prevented. , 0.2 mrad or more is more preferable, 2 mrad or less is preferable, and 0.7 mrad or less is more preferable.

The thickness of the entire interlayer film for laminated glass of the present invention is not particularly limited. The minimum thickness of the entire interlayer film for laminated glass of the present invention is preferably 250 μm or more, and more preferably 800 μm or more, because the penetration resistance of the laminated glass is sufficiently improved. Further, since the handleability of the laminated glass interlayer film is sufficiently improved, the maximum thickness of the entire laminated glass interlayer film of the present invention is preferably 2800 μm or less, more preferably 1800 μm or less, and 1200 μm. The following is more preferable.

When the distance between one end and the other end is X, the interlayer film has a minimum thickness in a region having a distance of 0X to 0.2X from one end to the inside, and 0X from the other end to the inside. The interlayer preferably has a maximum thickness in a region at a distance of ~ 0.2X, and the interlayer film has a minimum thickness in a region at a distance of 0X to 0.1X from one end to the inside and from the other end to the inside. It is more preferable to have the maximum thickness in the region of a distance of 0X to 0.1X. It is preferable that the interlayer film has a minimum thickness at one end and the interlayer film has a maximum thickness at the other end.

The method for producing the sound insulation interlayer film is not particularly limited. For example, the sound insulation layer and the protective layer are formed into a sheet by a usual film forming method such as an extrusion method, a calendar method, or a pressing method. Examples include a method of laminating.

The method for producing the interlayer film for laminated glass of the present invention is not particularly limited, and a conventionally known production method can be used.
Examples of the method for forming a large number of concave portions and a large number of convex portions on at least one surface of the interlayer film for laminated glass in the present invention include an embossing roll method, a calendar roll method, a deformed extrusion method, and a melt fracture method. Be done. Of these, the embossed roll method is preferable.

A laminated glass in which the interlayer film for laminated glass of the present invention is laminated between a pair of glass plates is also one of the present inventions.
As the glass plate, a generally used transparent plate glass can be used. For example, inorganic glass such as float plate glass, polished plate glass, template glass, meshed glass, wire-lined plate glass, colored plate glass, heat ray absorbing glass, heat ray reflecting glass, and green glass can be mentioned. Further, an ultraviolet shielding glass having an ultraviolet shielding coat layer formed on the surface of the glass can also be used. Further, an organic plastic plate such as polyethylene terephthalate, polycarbonate, or polyacrylate can also be used.
Two or more types of glass plates may be used as the glass plate. For example, a laminated glass in which an interlayer film for laminated glass of the present invention is laminated between a transparent float plate glass and a colored glass plate such as green glass can be mentioned. Further, as the glass plate, two or more kinds of glass plates having different thicknesses may be used.

The laminated glass of the present invention can be suitably produced by the nip roll method.
In the nip roll method, a laminated body in which a laminated glass interlayer film is laminated between at least two glass plates is conveyed by a conveyor, and the laminated body is heated to a constant temperature by passing through a heating zone. After that, the air remaining between the glass and the interlayer film is removed while being handled through the nip roll, and at the same time, thermocompression bonding is performed to reduce the air between the interlayer film and the glass of the laminated body and bring them into close contact with each other.
When the laminated body is conveyed by using a conveyor, the inclination of the engraved linear recesses of the interlayer film for laminated glass of the present invention is set to 55 ° or less with respect to the flow direction by the conveyor. Is preferable. As a result, it is possible to prevent the laminated glass from being displaced from the laminated glass interlayer film when moving by the conveyor, and high production efficiency can be realized. The inclination of the engraved line-shaped recesses of the interlayer film for laminated glass of the present invention during transportation using a conveyor is more preferably 45 ° or less, and more preferably 25 ° or less with respect to the flow direction by the conveyor. Is even more preferable.

According to the present invention, a laminated glass interlayer film capable of exhibiting high degassing properties even by the nip roll method and capable of producing a laminated glass having high visibility without generating bubbles, and the laminated glass interlayer film were used. Laminated glass can be provided.

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

(Example 1)
(Preparation of resin composition for protective layer)
With respect to 100 parts by mass of polyvinyl butyral (acetyl group amount 1 mol%, butyral group amount 69 mol%, hydroxyl group amount 30 mol%) obtained by acetalizing polyvinyl alcohol having an average degree of polymerization of 1700 with n-butyraldehyde. As a plasticizer, 36 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) was added. Further, as an adhesive strength modifier, a mixture of magnesium 2-ethylbutyrate and magnesium acetate (1: 1 by mass ratio) was added so that the magnesium content was 50 ppm. It was thoroughly kneaded with a mixing roll to obtain a resin composition for a protective layer.

(Preparation of resin composition for intermediate layer)
Polyvinyl butyral (acetyl group amount 12.5 mol%, butyral group amount 64 mol%, hydroxyl group amount 23.5 mol%) 100 obtained by acetalizing polyvinyl alcohol having an average degree of polymerization of 2300 with n-butyraldehyde. 76.5 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) was added as a plasticizer to parts by mass and sufficiently kneaded with a mixing roll to obtain a resin composition for an intermediate layer. ..

(Preparation of interlayer film for laminated glass)
By coextruding the obtained resin composition for intermediate layer and resin composition for protective layer with a coextruder, a resin composition for first protective layer and intermediate layer composed of the resin composition for protective layer. An interlayer film for laminated glass having a three-layer structure in which an intermediate layer composed of an intermediate layer and a second protective layer composed of a resin composition for a protective layer were laminated in this order was obtained.
In the laminated glass interlayer film obtained after the unevenness is applied, the cross-sectional shape of the first protective layer in the thickness direction is wedge-shaped, the maximum thickness is 525 μm, the minimum thickness is 350 μm, and the cross-sectional shape of the intermediate layer in the thickness direction is wedge-shaped and maximum. The thickness is 150 μm, the minimum thickness is 100 μm, the cross-sectional shape of the second protective layer in the thickness direction is wedge-shaped, the maximum thickness is 525 μm, the minimum thickness is 350 μm, the cross-sectional shape of the entire interlayer film in the thickness direction is wedge-shaped, and the maximum thickness is 1200 μm. The extrusion conditions were set so that the minimum thickness was 800 μm.

First, as the first step, the surface of the iron roll is subjected to random irregularities with a blasting agent, then the roll is vertically ground, and a finer blasting agent is used to apply fine irregularities to the flat portion after grinding. A pair of rolls of the same shape having a coarse main embossing and a fine sub-embossing were used as a concave-convex shape transfer device, and a random uneven shape was transferred to both sides of the obtained interlayer film for laminated glass. As the transfer conditions at this time, the temperature of the interlayer film for laminated glass was 80 ° C., the temperature of the roll was 145 ° C., the linear velocity was 10 m / min, and the press linear pressure was 10 to 200 kN / m.
As a second step, a pair of rolls consisting of a metal roll whose surface has been engraved using a triangular diagonal line mill and a rubber roll having a JIS hardness of 65 to 75 is used as a concave-convex shape transfer device, and the obtained combination is obtained. An interlayer film for glass is passed through this concave-convex shape transfer device to impart irregularities formed at equal intervals in parallel with recesses having a continuous groove shape (engraved line shape) at the bottom on one surface of the interlayer film for laminated glass. did. As the transfer conditions at this time, the temperature of the interlayer film for laminated glass was 70 ° C., the roll temperature was 145 ° C., the linear velocity was 10 m / min, and the press linear pressure was 5 to 100 kN / m.

(Evaluation of unevenness of interlayer film for laminated glass)
By a method according to JIS B-0601 (1994), the spacing Sm of the engraved recesses on the surface of the obtained laminated glass interlayer film, the radius of gyration R, and the roughness Rz of the engraved recesses were measured. The measurement direction is perpendicular to the engraved line, and the cutoff value is 2.5 mm, the reference length is 2.5 mm, the evaluation length is 12.5 mm, the tip radius of the stylus is 2 μm, and the tip angle is 60. The measurement was performed under the conditions of ° and measurement speed = 0.5 mm / s.
In addition, using an optical microscope (“BS-D8000III” manufactured by SONIC), the surface of the interlayer film for laminated glass was observed at 5 points each with an observation range of 20 mm × 20 mm, and the intervals between the engraved recesses were observed at 5 points, respectively. After measuring the interval between the two, the average value of the shortest distances between the bottoms of the adjacent recesses was calculated.
Further, the interlayer film for laminated glass is not deformed by using a single-edged razor (Feather Safety razor, FAS-10) in the direction perpendicular to the direction of the engraved concave portion and in parallel with the film thickness direction. As described above, the razor was cut by extruding it in the direction parallel to the thickness direction without sliding in the direction perpendicular to the recess, and the cross section was observed using a microscope (“DSX-100” manufactured by Olympus). The circle when a circle inscribed in the bottom of the engraved concave portion is drawn in a state where the cross section is photographed at a measurement magnification of 208 times and the photographed image is enlarged and displayed so as to be 50 μm / 20 mm. (That is, the radius of gyration R) was obtained. The Rz on the film surface after the first step was 15 μm.
Table 1 shows the measured values for the unevenness of the front surface and the back surface of the interlayer film for laminated glass.

(Measurement of plasticizer content)
After preparing the laminated glass, it was allowed to stand for 4 weeks in an environment of a temperature of 25 ° C. and a humidity of 30%. Then, the laminated glass was cooled with liquid nitrogen to peel off the glass and the interlayer film for laminated glass. The obtained protective layer and sound insulation layer are cut in the thickness direction and allowed to stand in an environment of a temperature of 25 ° C. and a humidity of 30% for 2 hours, and then a finger or a machine is inserted between the protective layer and the sound insulation layer. The peeling was performed in an environment of a temperature of 25 ° C. and a humidity of 30%, and a rectangular measurement sample of 10 g was obtained for each of the protective layer and the sound insulation layer. For the measurement sample, the plasticizer was extracted with diethyl ether for 12 hours using a Soxhlet extractor, and then the plasticizer in the measurement sample was quantified to determine the content of the plasticizer in the protective layer and the intermediate layer.

(Examples 2 to 8 and Comparative Examples 1 to 3)
The acetyl group amount, butyral group amount and hydroxyl group amount of the polyvinyl butyral used are changed as shown in Table 1, and the shape of the embossed roll in the first step and the shape of the unevenness given by changing the triangular diagonal line type roll are changed. However, except that the cross-sectional shape, minimum thickness, maximum thickness and wedge angle in the thickness direction of the first protective layer, the intermediate layer, the second protective layer and the entire interlayer film are changed to Tables 1 to 3, the same as in Example 1. An interlayer film for laminated glass was prepared in the same manner. Tables 1 to 3 show the measured values for the unevenness of the front surface and the back surface of the interlayer film for laminated glass obtained in Examples and Comparative Examples.

(Evaluation)
The interlayer films for laminated glass obtained in Examples and Comparative Examples were evaluated by the following methods.
The results are shown in Tables 1-3.

<Evaluation by nip roll method>
(1) Evaluation of Embossed Shape Remaining After Pre-Crimping The interlayer film for laminated glass obtained in Examples and Comparative Examples was placed in an environment of 23 ° C. and 30 RH% for 5 hours, and then subjected to the subsequent operation.
Vertically so that the center of the glass comes to a position 30 cm from the thicker end of the obtained laminated glass interlayer film and the horizontal direction of the clear glass plate is parallel to the flow direction of the film. The interlayer film for laminated glass is sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction is parallel to the width direction of the film to form a laminated body. A laminate was obtained by primary degassing with a nip roll (roll pressure 2 kgf / cm ² ). Further, the laminate is passed through an infrared oven while being conveyed by a roller conveyor, heated to a surface temperature of 50 ° C., and then secondarily degassed and laminated with a second nip roll (roll pressure 4 kgf / cm ² ). I got a body.
The obtained laminate is further placed on a roller conveyor and conveyed, passed through an infrared oven, heated so that the glass surface temperature of the laminate becomes 85 ° C., and then a third nip roll (roll pressure 4 kgf /). By handling through cm ² ), the tertiary degassing was performed while degassing the air remaining between the glass plate and the interlayer film, and the preliminary crimping was completed. The gap between the nip rolls when passing each nip roll was 1 mm narrower than the average thickness of the laminated body, and the peripheral speed of the nip roll was set to 5 m / min. Table 1 shows the angles between the engraved concave portions formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

The laminate after pre-crimping was immersed in liquid nitrogen and cooled sufficiently to peel off the glass so that no glass remained on the surface of the interlayer film, thereby obtaining an interlayer film sheet. The obtained interlayer film sheet was allowed to stand at 23 ° C. and 30 RH% for 1 hour, and then the surface of the interlayer film sheet was subjected to a remaining embossed shape by a three-dimensional surface shape measuring machine (Contour GT-K manufactured by Bulker AXS). Was measured. The embossed shape was measured by the three-dimensional surface shape measuring machine within 24 hours.
As measurement points, 20 points were measured in a region of 10 to 20 cm from the glass end on the traveling direction side when conveyed by the roller conveyor and 3 cm away from the left and right glass ends. The measurement field of view per measurement was 1.3 mm × 1.3 mm.
From the obtained 3D shape, the volume of the remaining groove shape was measured by the analysis software "Multivision analysis" attached to the 3D surface shape measuring machine. The reference surface for calculating the volume was the peeled surface of the glass and the film. The "ZeroLevel" condition in the Multivision analysis condition was set as "BackGround" and the value of the "By Thrashold" item was adjusted.
The average groove volume per area was calculated, and those with an average of 20 points measured exceeding 1.5 μm ³ / μm ² (= μm) are “x”, 1.0 μm ³ / μm ² (= μm) or more 1. Those having a size of 5 μm ³ / μm ² (= μm) or less were evaluated as “◯”, and those having a size of less than 1.0 μm ³ / μm ² (= μm) were evaluated as “⊚”. The average groove volume is the average value of the groove volumes on the front and back surfaces at the same point.

(2) Evaluation of foaming of laminated glass (Condition 1)
The interlayer films for laminated glass obtained in Examples and Comparative Examples were placed in an environment of 23 ° C. and 30 RH% for 5 hours, and then subjected to the subsequent operations.
Vertically so that the center of the glass comes to a position 30 cm from the thicker end of the obtained laminated glass interlayer film and the horizontal direction of the clear glass plate is parallel to the flow direction of the film. The interlayer film for laminated glass is sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction is parallel to the width direction of the film to form a laminated body. A laminate was obtained by primary degassing with a nip roll (roll pressure 2 kgf / cm ² ). Further, the laminate is passed through an infrared oven while being conveyed by a roller conveyor, heated to a surface temperature of 50 ° C., and then secondarily degassed and laminated with a second nip roll (roll pressure 4 kgf / cm ² ). I got a body.

The obtained laminate is further placed on a roller conveyor and conveyed, passed through an infrared oven, heated so that the glass surface temperature of the laminate becomes 85 ° C., and then a third nip roll (roll pressure 4 kgf /). By handling through cm ² ), the tertiary degassing was performed while degassing the air remaining between the glass plate and the interlayer film, and the preliminary crimping was completed. The gap between the nip rolls when passing each nip roll was 1 mm narrower than the average thickness of the laminated body, and the peripheral speed of the nip roll was set to 5 m / min. Tables 1 to 3 show the angles between the engraved concave portions formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

(3) Evaluation of foaming of laminated glass (Condition 2)
The interlayer films for laminated glass obtained in Examples and Comparative Examples were placed in an environment of 23 ° C. and 30 RH% for 5 hours, and then subjected to the subsequent operations.
Vertically so that the center of the glass comes to a position 30 cm from the thicker end of the obtained laminated glass interlayer film and the horizontal direction of the clear glass plate is parallel to the flow direction of the film. The interlayer film for laminated glass is sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction is parallel to the width direction of the film to form a laminated body. A laminate was obtained by primary degassing with a nip roll (roll pressure 2 kgf / cm ² ). Further, the laminate is passed through an infrared oven while being conveyed by a roller conveyor, heated to a surface temperature of 70 ° C., and then secondarily degassed and laminated with a second nip roll (roll pressure 4 kgf / cm ² ). I got a body.
The gap between the nip rolls when passing each nip roll was 1 mm narrower than the average thickness of the laminated body, and the peripheral speed of the nip roll was set to 5 m / min. Tables 1 to 3 show the angles between the engraved concave portions formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

(4) Evaluation of foaming of laminated glass (Condition 3)
The interlayer films for laminated glass obtained in Examples and Comparative Examples were placed in an environment of 23 ° C. and 30 RH% for 5 hours, and then subjected to the subsequent operations.
Vertically so that the center of the glass comes to a position 30 cm from the thicker end of the obtained laminated glass interlayer film and the horizontal direction of the clear glass plate is parallel to the flow direction of the film. The interlayer film for laminated glass is sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction is parallel to the width direction of the film to form a laminated body. A laminate was obtained by primary degassing with a nip roll (roll pressure 2 kgf / cm ² ). Further, the laminate is passed through an infrared oven while being conveyed by a roller conveyor, heated to a surface temperature of 60 ° C., and then secondarily degassed and laminated with a second nip roll (roll pressure 4 kgf / cm ² ). I got a body.
The gap between the nip rolls when passing each nip roll was 1 mm narrower than the thickness of the laminated body, and the peripheral speed of the nip roll was set to 5 m / min. Tables 1 to 3 show the angles between the engraved concave portions formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

The laminate obtained under the evaluation conditions 1 to 3 of the foaming of the laminated glass was maintained at a pressure of 13 atm and a temperature of 140 ° C. in the tank for 20 minutes using an autoclave device, and then the temperature in the tank was set to 40 ° C. After cooling to the maximum, the pressure was reduced to 1 atm to prepare a laminated glass.
Further, the laminated glass was stored in an oven at 140 ° C. for 2 hours, then taken out of the oven and allowed to cool for 3 hours, and then the appearance of the laminated glass was visually observed. For each of the 20 sheets, the number of bubbles (bubbles) generated between the glass plate and the interlayer film for laminated glass was examined, and it was determined whether or not bubbles were generated in a region 1 cm or more away from the edge of the glass. The case where the number of bubbles was 5 or less was evaluated as "◯", and the case where the number of foams was 6 or more was evaluated as "x".

<Evaluation by vacuum degassing method>
(Evaluation of degassing after preliminary crimping by vacuum back method)
The obtained interlayer film for laminated glass was sandwiched between two clear glass plates (length 15 cm × width 15 cm × thickness 2.5 mm), and the protruding portion was cut off to obtain a laminated body. The obtained laminate is preheated in an oven until the surface temperature of the glass reaches 50 ° C., then transferred into a rubber bag, the rubber bag is connected to a suction decompressor, and at the same time, it is heated and held under a reduced pressure of -600 mmHg. While heating the laminated body to 90 ° C. for 18 minutes, the temperature of the laminated body was returned to atmospheric pressure to complete the preliminary crimping, and a laminated body was obtained after pre-deaeration.

The parallel light transmittance of the obtained laminated body after preliminary degassing was evaluated by the following method.
That is, in accordance with JIS K 7105, the parallel light transmittance Tp (%) of the laminated body after preliminary degassing was measured using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute).
The measurement position is the central part where the two diagonal lines of the pre-degassed laminate intersect, and the average value is 5 points including 4 points diagonally 5.6 cm apart from each apex of the pre-degassed laminate. It was set to Tp.
Before the measurement, the sample was cut out from the laminate to a size within a range that does not affect the measured value, centering on the above measurement point.
The decrease in transparency of the laminated glass is caused by poor deaeration during preliminary crimping. Therefore, the degassing property of the interlayer film for laminated glass can be evaluated more accurately by measuring the visible light transmittance of the laminated body after the preliminary degassing, rather than evaluating the foamability of the laminated glass.

According to the present invention, a laminated glass interlayer film capable of exhibiting high degassing properties even by the nip roll method and capable of producing a laminated glass having high visibility without generating bubbles, and the laminated glass interlayer film were used. Laminated glass can be provided.

Claims (3)

Laminated glass having a large number of concave portions and a large number of convex portions on at least one surface, the concave portions having a continuous groove shape at the bottom, and the adjacent concave portions being parallel and regularly arranged in parallel. Laminated glass
The ratio (R / Sm × 100) of the radius of gyration R of the bottom of the groove-shaped recess having a continuous bottom to the distance Sm of the groove-shaped recess having a continuous bottom is 29.3% or more .
An interlayer film for laminated glass, which has one end and the other end on the opposite side of the one end, and the thickness of the other end is larger than the thickness of the one end. The interlayer film for laminated glass according to claim 1 , wherein the radius of gyration R of the bottom of the groove-shaped recess having a continuous bottom is 20 to 250 μm. The interlayer film for laminated glass according to claim 1 or 2, wherein the interval Sm of the groove-shaped recesses having a continuous bottom is 100 to 400 μm.