JP7252928B2 - Interlayer film for laminated glass and laminated glass - Google Patents

Description

The present invention provides an interlayer film for laminated glass that can exhibit high degassing properties even by a nip roll method and can produce laminated glass with high visibility without generating air bubbles, and laminated glass using the interlayer film for laminated glass. I will provide a.

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.

A vacuum degassing method is used as one of the methods for manufacturing such windshields for automobiles.
In the vacuum degassing method, a laminate in which an interlayer film for laminated glass is laminated between at least two glass plates is placed in a rubber bag and vacuum suction is performed to remove air remaining between the glass plate and the interlayer film. Preliminary pressure bonding is performed while heating and pressing, and then, for example, the main pressure bonding is performed by heating and pressurizing in an autoclave to obtain an automobile windshield.

In the manufacturing process of laminated glass by the vacuum degassing method, degassability is important when laminating glass and an interlayer film for laminated glass. For this reason, fine irregularities are formed on at least one surface of the intermediate film for laminated glass for the purpose of ensuring degassability during production of laminated glass. In particular, the recesses in the unevenness have a continuous groove shape (ruled line shape) at the bottom, and the adjacent grooved line-shaped recesses are formed in parallel and regularly. It can exhibit degassing properties (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 laminate in which an interlayer film for laminated glass is laminated between at least two glass plates is conveyed using a conveyor, and the laminate is passed through a heating zone to be heated to a constant temperature. After that, air remaining between the glass and the intermediate film is removed through nip rolls while being hot-pressed to reduce the air between the intermediate film and the glass of the laminate and to adhere them.

However, when laminated glass is produced by the nip roll method using an interlayer film for laminated glass that has been used to produce laminated glass by the vacuum degassing method, there is a problem that the degassability of the resulting laminated glass may be reduced. was there.

JP-A-2001-48599

The present inventors conducted research on the cause of the deterioration of the deaeration properties of the laminated glass obtained when the laminated glass is produced by the nip roll method. As a result, it was found that the cause was groove-shaped recesses with continuous bottoms (hereinafter also referred to as "ruled-line recesses") formed on the surface of the interlayer film for laminated glass for degassing. In the vacuum degassing method, pressure reduction and heating are performed at the same time for pre-compression bonding, so air inside the scored recesses is removed by the pressure reduction, so that the recesses remain in the obtained laminated glass without being crushed. It was almost never a problem. However, in the nip roll method, the film and the glass are pressure-bonded only by pressure during the preliminary pressure-bonding, so that the concave portions may remain without being crushed after the preliminary pressure-bonding. If there is a large amount of air remaining in the recesses that remain without being crushed, air bubbles may remain in the film even after pressurized, heated and pressed in an autoclave, resulting in a decrease in visibility. In addition, particularly when the temperature of the laminated glass precursor is low during pre-press bonding, the concave portions are less likely to collapse and air bubbles tend to remain.

The present invention provides an interlayer film for laminated glass that can exhibit high degassing properties even by a nip roll method and can produce laminated glass with high visibility without generating air bubbles, and laminated glass using the interlayer film for laminated glass. intended to provide The interlayer film for laminated glass according to the present invention may be used not only for the nip roll method but also for 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 groove shapes with continuous bottoms, and the adjacent concave portions are arranged in parallel and regularly. wherein the ratio (R/Sm×100) of the rotation radius R of the bottom of the groove-shaped recesses with continuous bottoms to the interval Sm between the groove-shaped recesses with continuous bottoms is 15 % or more, and has one end and the other end on the opposite side of the one end, wherein 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 "having a large number of concave portions and a large number of convex portions 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 arranged" means that "the recess has a groove shape with a continuous bottom. and that the adjacent recesses are formed in parallel and regularly."
The present invention will be described in detail below.

As a result of intensive studies, the inventors of the present invention have found that by making the irregular shape of the intermediate film for laminated glass into a specific one, it is possible to exhibit high deaeration even by the nip roll method, and to produce laminated glass with high visibility. I found that I could do it, and completed the present invention. The interlayer film for laminated glass according to the present invention may be used not only for the nip roll method but also for 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, the concave portions having a groove shape with a continuous bottom, and the adjacent concave portions being parallel to each other. are regularly arranged in parallel. As a result, it is possible to ensure the degassing property during the production of laminated glass by the nip roll method. Although the unevenness may be provided only on one surface, it is preferable to have the unevenness on both surfaces 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 uneven recesses on at least one surface have a groove shape with a continuous bottom (that is, have a "ruled-line recess"), and the adjacent recesses are arranged in parallel and regularly. In general, the ease with which air escapes when a laminate in which an intermediate film for laminated glass is laminated between two glass plates is pressure-bonded is closely related to the continuity and smoothness of the bottom of the recess. By making the irregularities on at least one surface of the intermediate film into a shape in which the grooved grooves are arranged in parallel and regularly, the communication of the bottom portion is excellent, and the degassing property is remarkably improved.
In addition, "regularly arranged in parallel" means that the adjacent ruled line-shaped recesses may be parallel and arranged at equal intervals, and the adjacent ruled line-shaped recesses may be arranged in parallel. However, it means that the intervals between all the adjacent ruled line-shaped recesses need not be equal. Further, the recess on the ruled line does not need to have a continuous groove shape over the entire bottom portion, and may have a dividing wall in a part of the bottom portion. Also, as long as adjacent recesses are arranged in parallel and regularly, the shape of the groove at the bottom need not 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 recesses with continuous bottoms to the interval Sm of the groove-shaped recesses with continuous bottoms is 15. % or more. As a result, when manufacturing laminated glass by the nip roll method, it is possible to exhibit sufficient degassing properties during preliminary pressure bonding, and the pressure during preliminary pressure bonding can crush the grooved recesses, preventing air from remaining. Then, transparent laminated glass without air bubbles can be obtained.
The ratio (R/Sm×100) of the rotation radius R of the bottom of the groove-shaped recess with continuous bottom to the interval Sm of the groove-shaped recess with continuous bottom is preferably 20% or more, and preferably 30% or more. is more preferably 50% or more. The ratio (R/Sm×100) of the radius of gyration R of the bottom of the groove-shaped recesses with continuous bottoms to the interval Sm between the groove-shaped recesses with continuous bottoms is preferably 200% or less, More preferably, it is 100% or less.

In this specification, the rotation radius R of the bottom of the scored line-shaped recess is measured by applying an intermediate film for laminated glass in the direction of the scored line-shaped recess using a single-edged razor (eg, FAS-10 manufactured by Feather Safety Razor). In the vertical direction and parallel to the thickness direction, cut by pushing out 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, and cut the cross section microscopically. Observed using a scope (for example, Olympus DSX-100), photographed at a measurement magnification of 208 times, and further expanded the photographed image to 50 μm / 20 mm. When a circle inscribed in the bottom of the grooved groove is drawn using measurement software, the radius of the circle is defined as the radius of rotation R of the groove. Moreover, the environment at the time of measurement is 23° C. and 30 RH %. Here, 5 arbitrary points in the intermediate film are taken as samples, R is measured at 3 points for each sample, and the average value of 15 points in total is defined as R.
Further, the interval Sm between the grooved grooves in the present specification is specified in JIS B-0601 (1994). The interval Sm between the grooved grooves is obtained by observing the first and second surfaces (observation range: 20 mm × 20 mm) of the interlayer film for laminated glass using an optical microscope ("BS-D8000III" manufactured by SONIC). , is obtained by measuring the distance between adjacent recesses and calculating the average value of the shortest distances between the bottoms of adjacent recesses.

A preferred lower limit of the radius of gyration R of the bottom of the grooved line is 20 μm, and a preferred upper limit is 250 μm. If the rotation radius R of the bottom of the ruled line-shaped recess is within this range, it is easier to crush the ruled line-shaped recesses by the pressure during pre-press bonding in the case of manufacturing laminated glass by the nip roll method. , exhibit better degassing properties. A more preferable lower limit of the radius of gyration R of the bottom of the grooved groove is 40 μm, and a more preferable upper limit thereof is 125 μm.

A preferable lower limit of the interval Sm between the grooved grooves is 50 μm, and a preferable upper limit thereof is 1000 μm. If the interval Sm between the ruled line-shaped recesses is within this range, in the case of manufacturing laminated glass by the nip roll method, excellent degassing property is exhibited during pre-press bonding, and the pressure causes the ruled line-shaped recesses to be formed. becomes easier to destroy. A more preferable lower limit of the interval Sm between the grooved grooves is 100 μm, a more preferable lower limit is 175 μm, a more preferable upper limit is 400 μm, and a further preferable upper limit is 300 μm. By setting the interval between the grooved grooves to be equal to or greater than the lower limit, good degassing properties can be obtained even in a vacuum bag system.

A preferable lower limit of the roughness (Rz) of the ruled line-shaped recesses is 10 μm, and a preferable upper limit thereof is 80 μm. By setting the roughness (Rz) of the ruled line-shaped concave portions within this range, excellent degassing properties can be exhibited. A more preferable lower limit of the roughness (Rz) of the ruled line-shaped recesses is 20 μm, and a more preferable upper limit thereof is 65 μm. A more preferable upper limit is 50 μm.
In this specification, the roughness (Rz) of the grooved grooves is defined in JIS B-0601 (1994), and is measured in the vertical direction so as to cross the continuous direction of the grooved grooves in the grooved direction. obtained by doing Here, as a measuring machine, for example, "Surfcorder SE300" manufactured by Kosaka Laboratory Co., Ltd. can be used. , the preliminary length is 2.5 mm, the feeding speed of the palpation needle is 0.5 mm/sec, and the shape of the stylus is 2 μm in tip radius and 60° in tip angle. Moreover, the environment at the time of measurement is 23° C. and 30 RH %. In addition, the intermediate film to be measured is measured after being allowed to stand still for 3 hours or more under 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' of the tips of the projections of the unevenness is 15 μm. As a result, the frictional force between the glass and the interlayer film for laminated glass increases, and when manufacturing laminated glass by the nip roll method, it is possible to more effectively prevent the glass and the interlayer film for laminated glass from being displaced on the conveyor. can be prevented. Although the upper limit of the radius of gyration R′ of the tip of the convex portion is not particularly limited, it is preferably 100 μm or less. As a result, even when the intermediate films are laminated together, the films do not adhere to each other, and the handleability is improved. A more preferable lower limit of the radius of gyration R′ of the tip of the convex portion is 30 μm, and a more preferable upper limit thereof is 80 μm.
Note that the turning radius R′ of the tip of the convex portion is obtained by cutting the intermediate film in the direction perpendicular to the direction of the grooved concave portion and in the film thickness direction, and observing the cross section with a microscope (for example, Olympus Co. "DSX-100"), photographed at a measurement magnification of 555 times, and further enlarged to 50 μ / 20 mm. It can be obtained by a method in which the radius of a circle inscribed in the vertex of the convex shape is drawn as the radius of rotation of the tip of the convex portion. Moreover, the environment at the time of measurement is 23° C. and 30 RH %.

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, polytrifluoride, 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. Among them, 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 acetalized product of polyvinyl alcohol. The degree of saponification of PVA is generally within 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 still more preferably. is 3000 or less, more preferably less than 3000, particularly preferably 2800 or less. The polyvinyl acetal is preferably a polyvinyl acetal obtained by acetalizing PVA having a degree of polymerization equal to or higher than the lower limit and equal to or lower than the upper limit. When the degree of polymerization is equal to or higher than the lower limit, the penetration resistance of the laminated glass is further enhanced. When the degree of polymerization is equal to or less than the upper limit, molding of the intermediate film is facilitated.

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, an aldehyde having 1 to 10 carbon atoms is generally preferably used. Examples of the aldehyde having 1 to 10 carbon atoms include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, Examples include n-nonylaldehyde, n-decylaldehyde and benzaldehyde. Among them, n-butyraldehyde, n-hexylaldehyde and n-valeraldehyde are preferred, and n-butyraldehyde is more preferred. Only one kind of the aldehyde may be used, or two or more kinds thereof may be used in combination.

The polyvinyl acetal is preferably polyvinyl butyral. The use of polyvinyl butyral further enhances the weather resistance of the interlayer to the laminated glass member.

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 commonly used for interlayer films for laminated glass. Examples include phosphoric acid plasticizers such as phosphoric acid compounds and organic phosphorous compounds.
Examples of the organic plasticizer include triethylene glycol-di-2-ethylhexanoate, triethylene glycol-di-2-ethylbutyrate, triethylene glycol-di-n-heptanoate, tetraethylene glycol-di-2 - ethylhexanoate, 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. Among them, triethylene glycol-di-2-ethylhexanoate, triethylene glycol-di-2-ethylbutyrate, or triethylene glycol-di-n-heptanoate is preferably included, and triethylene glycol-di -2-ethylhexanoate is more preferred.

The interlayer film for laminated glass of the present invention preferably contains an adhesive strength modifier.
Alkali metal salts or alkaline earth metal salts, for example, are preferably used as the adhesion modifier. Examples of the adhesive strength modifier include salts of potassium, sodium, magnesium and the like.
Examples of the acid constituting the salt include organic acids such as octylic acid, hexylic 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 may optionally contain an antioxidant, a light stabilizer, a modified silicone oil as an adhesion regulator, a flame retardant, an antistatic agent, a moisture resistant agent, a heat ray reflector, a heat ray absorber, and the like. may contain additives.

The interlayer film for laminated glass of the present invention has one end and the other end opposite to the one end. The one end and the other end are opposite ends of the intermediate film. In the interlayer film for laminated glass of the present invention, the thickness of the other end is greater 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, double images 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.
As used herein, glossiness means 75 degree specular gloss measured in accordance with JIS Z 8741:1997 using a precision gloss meter (for example, "GM-26PRO" manufactured by Murakami Color Laboratory). . An intermediate 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 further preferable upper limit is 10% or less. When the glossiness is 3% or more, it suppresses the fine irregularities from remaining between the film and the glass during pre-press bonding, and prevents air bubbles from remaining in the film even after pressurized, heated and pressed in 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 insulation layer. , an interlayer film for laminated glass (hereinafter also referred to as a "sound insulation interlayer") having excellent sound insulation properties, in which a sound insulation layer is sandwiched between two protective layers.
The sound insulation intermediate film will be described in more detail below.

In the sound insulation interlayer film, the sound insulation layer has a role of providing 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 acetalized product of polyvinyl alcohol. The polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate.
The preferred lower limit of the degree of polymerization of polyvinyl alcohol is 200, and the preferred upper limit is 5,000. By setting the polymerization degree of the polyvinyl alcohol to 200 or more, the penetration resistance of the resulting sound insulation interlayer film can be improved, and by setting it to 5000 or less, the formability of the sound insulation layer can be ensured. A more preferable lower limit of the polymerization degree of the polyvinyl alcohol is 500, and a more preferable upper limit thereof is 4,000.

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 in the aldehyde to 4 or more, a sufficient amount of the 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 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, n-valeraldehyde and the like. .

A preferable upper limit of the amount of hydroxyl groups in the polyvinyl acetal X is 30 mol %. By setting the amount of hydroxyl groups in the polyvinyl acetal X to 30 mol % or less, the plasticizer can be contained in an amount necessary to exhibit sound insulating properties, and bleeding out of the plasticizer can be prevented. The more preferable upper limit of the amount of hydroxyl groups in 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 more preferable lower limit. is 20 mol %.
The amount of hydroxyl groups in the polyvinyl acetal X is a value expressed as a percentage (mol %) of the mole fraction obtained by dividing the amount of ethylene groups to which 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 obtained by measuring the amount of ethylene groups to which the hydroxyl groups of the polyvinyl acetal X are bonded, for example, by a method conforming to JIS K6728 "Polyvinyl butyral test method". can.

A preferable lower limit of the acetal group content of the polyvinyl acetal X is 60 mol %, and a preferable upper limit thereof is 85 mol %. By setting the acetal group content of the polyvinyl acetal X to 60 mol% or more, the hydrophobicity of the sound insulation layer can be increased, and the necessary amount of plasticizer to exhibit sound insulation can be contained. bleed out and whitening can be prevented. By setting the acetal group content of the polyvinyl acetal X to 85 mol % or less, it is possible to facilitate the synthesis of the polyvinyl acetal X and ensure the productivity. The amount of acetal groups can be obtained by measuring the amount of ethylene groups to which the acetal groups of the polyvinyl acetal X are bonded by a method conforming to JIS K6728 "Polyvinyl butyral test method".

The preferred lower limit of the acetyl group content of the polyvinyl acetal X is 0.1 mol %, and the preferred upper limit is 30 mol %. By setting the amount of acetyl groups in the polyvinyl acetal X to 0.1 mol % or more, it is possible to contain a necessary amount of plasticizer to exhibit sound insulating properties and prevent bleeding out. Further, by setting the acetyl group content of the polyvinyl acetal X to 30 mol % or less, the hydrophobicity of the sound insulating layer can be increased, and whitening can be prevented. The more preferable lower limit of the acetyl group amount is 1 mol%, the more 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 amount of acetyl groups is the total amount of ethylene groups in the main chain minus the amount of ethylene groups to which acetal groups are bonded and the amount of ethylene groups to which hydroxyl groups are bonded. It is a value expressed as a percentage (mol %) of the mole fraction obtained by dividing by .

In particular, the polyvinyl acetal X can be a polyvinyl acetal having an acetyl group content of 8 mol% or more, or The polyvinyl acetal preferably has an acetyl group content of less than 8 mol % and an acetal group content of 68 mol % or more.

The preferable lower limit of the content of the plasticizer in the sound insulation layer is 45 parts by mass, and the preferable upper limit thereof 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. A decrease in transparency and adhesiveness can be prevented. A more preferable lower limit of the plasticizer content is 50 parts by mass, a more preferable lower limit is 55 parts by mass, a more preferable upper limit is 75 parts by mass, and a further preferable upper limit is 70 parts by mass. The plasticizer content in the sound insulating layer may be the plasticizer content before the production of the laminated glass or the plasticizer content after the production of the laminated glass. The plasticizer content after the production of laminated glass can be measured according to the following procedure. After the laminated glass is produced, it is allowed to stand for 4 weeks under an environment with a temperature of 25° C. and a humidity of 30%. Thereafter, 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 were cut in the thickness direction, left to stand for 2 hours in an environment with a temperature of 25° C. and a humidity of 30%, then a finger or a machine was inserted between the protective layer and the sound insulation layer, Peel off under an environment of 25° C. temperature and 30% humidity to obtain 10 g rectangular measurement samples for each of the protective layer and the sound insulation layer. After extracting the plasticizer from the measurement sample with diethyl ether for 12 hours using a Soxhlet extractor, the plasticizer in the measurement sample is quantified to determine the plasticizer content in the protective layer and the intermediate layer.

The interlayer film for laminated glass of the present invention may have a shape in which the laminated glass as a whole 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 thickness of the sound insulation layer may be uniform throughout the sound insulation layer or may be different. 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. It is preferable that the sound insulation layer has a portion having a wedge-shaped cross section in the thickness direction. A 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 insulating layer is 80 μm, and a further preferable lower limit is 100 μm. Although the upper limit of the maximum thickness of the sound insulating layer is not particularly limited, 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 the plasticizer contained in the sound insulation layer from bleeding out, thereby preventing the adhesion between the interlayer film for laminated glass and the glass from deteriorating, and also prevents the interlayer film for laminated glass from penetrating. It has a role to give
For example, the protective layer preferably contains polyvinyl acetal Y and a plasticizer, and more preferably contains polyvinyl acetal Y having a larger hydroxyl group content than polyvinyl acetal X and a plasticizer.

The polyvinyl acetal Y can be prepared by acetalizing polyvinyl alcohol with an aldehyde. The polyvinyl acetal Y is preferably an acetalized product of polyvinyl alcohol.
The polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate. The preferable lower limit of the degree of polymerization of polyvinyl alcohol is 200, and the preferable upper limit is 5,000. By setting the polymerization degree of the polyvinyl alcohol to 200 or more, the penetration resistance of the interlayer film for laminated glass can be improved, and by setting it to 5000 or less, the formability of the protective layer can be ensured. A more preferable lower limit of the polymerization degree of the polyvinyl alcohol is 500, and a more preferable upper limit thereof is 4,000.

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 carbon number of the aldehyde to 3 or more, the penetration resistance of the interlayer film for laminated glass is enhanced. By setting the carbon number of the aldehyde to 4 or less, the productivity of the 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.

A preferable upper limit of the amount of hydroxyl groups in the polyvinyl acetal Y is 33 mol %, and a preferable lower limit thereof is 28 mol %. By setting the amount of hydroxyl groups in 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 in the polyvinyl acetal Y to 28 mol % or more, the penetration resistance of the interlayer film for laminated glass is enhanced.

The preferable lower limit of the acetal group content of the polyvinyl acetal Y is 60 mol %, and the preferable upper limit thereof is 80 mol %. By setting the amount of the acetal group to 60 mol % or more, the amount of plasticizer necessary for exhibiting sufficient penetration resistance can be contained. By setting the amount of the acetal group to 80 mol % or less, it is possible to ensure the adhesive strength between the protective layer and the glass. A more preferable lower limit of the acetal group content is 65 mol %, and a more preferable upper limit is 69 mol %.

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

The preferable lower limit of the content of the plasticizer in the protective layer is 20 parts by mass, and the preferable upper limit thereof 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, bleeding out of the plasticizer is prevented and the interlayer film for laminated glass is obtained. It is possible to prevent deterioration of the transparency and adhesiveness of the adhesive. A more preferable lower limit of the plasticizer content is 30 parts by mass, a more preferable lower limit is 35 parts by mass, a more preferable upper limit is 43 parts by mass, and a further preferable upper limit is 41 parts by mass. The content of the plasticizer in the protective layer is preferably lower than the content of the plasticizer in the sound insulation layer, since the sound insulation of the laminated glass is further improved. The plasticizer content in the protective layer may be the plasticizer content before the production of the laminated glass or the plasticizer content after the production of the laminated glass. The content of the plasticizer after the production of the laminated glass can be measured by the same procedure as for the sound insulating layer.

The amount of hydroxyl groups in polyvinyl acetal Y is preferably larger than the amount of hydroxyl groups in polyvinyl acetal X, more preferably by 1 mol% or more, and even more preferably by 5 mol% or more, because the sound insulation of the laminated glass is further improved. Preferably, it is particularly preferably greater than 8 mol %. By adjusting the amount of hydroxyl groups in polyvinyl acetal X and polyvinyl acetal Y, it is possible to control the content of the plasticizer in the sound insulation layer and the protective layer, thereby lowering the glass transition temperature of the sound insulation layer. As a result, the sound insulation of the laminated glass is further improved.
In addition, since the sound insulation of the laminated glass is further improved, the content of the plasticizer (hereinafter also referred to as content X) with respect to 100 parts by mass of polyvinyl acetal X in the sound insulation layer is It is preferably greater 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, still more 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 a shape in which the laminated glass as a whole 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 thickness of the protective layer may be uniform over the entire protective layer, or may be different. 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. It is preferable that the protective layer has a portion having a wedge-shaped cross section in the thickness direction.
The thickness of the protective layer is not particularly limited, and may be adjusted within a range where the protective layer can function. However, in the case where the protective layer has unevenness, it is preferable to increase the thickness as much as possible so as to suppress transfer of the unevenness to the interface with the sound insulation layer that is in direct contact with the protective layer. Specifically, the minimum thickness of the protective layer is preferably 100 µm, more preferably 300 µm, still more preferably 400 µm, and particularly preferably 450 µm. The upper limit of the maximum thickness of the protective layer is not particularly limited, but in order to ensure the thickness of the sound insulation layer to the extent that sufficient sound insulation can be achieved, the upper limit is substantially about 1000 μm, and 800 μm is preferable. .

The interlayer film for laminated glass of the present invention preferably has a portion having a wedge-shaped cross section in the thickness direction as a whole. Since the cross-sectional shape in the thickness direction of the entire interlayer film for laminated glass is wedge-shaped, when the laminated glass using the interlayer film for laminated glass of the present invention is used as a head-up display, double images are effectively generated. can be prevented. When the thickness direction cross-sectional shape 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 it is possible to effectively prevent the occurrence of double images. , more preferably 0.2 mrad or more, preferably 2 mrad or less, and more preferably 0.7 mrad or less.

The overall thickness of the 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, more preferably 800 μm or more, because the penetration resistance of the laminated glass is sufficiently improved. In addition, the maximum thickness of the entire interlayer film for laminated glass of the present invention is preferably 2800 μm or less, more preferably 1800 μm or less, more preferably 1200 μm, because the handleability of the interlayer film for laminated glass is sufficiently improved. More preferably:

When the distance between one end and the other end is X, the intermediate film has a minimum thickness in a region of a distance of 0X to 0.2X inward from one end, and 0X inward from the other end. Preferably, the interlayer has a maximum thickness in the region of a distance of ~0.2X and the interlayer has a minimum thickness in the region of a distance of 0X to 0.1X inward from one end and inward from the other end. More preferably, it has a maximum thickness in the region of distance 0X to 0.1X. Preferably, the interlayer has a minimum thickness at one end and the interlayer has a maximum thickness at the other end.

The method for producing the sound insulation interlayer film is not particularly limited. The method of laminating|stacking, etc. are mentioned.

The method for producing the interlayer film for laminated glass of the present invention is not particularly limited, and conventionally known production methods 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 profile extrusion method, a melt fracture method, and the like. be done. Among them, the embossing roll method is suitable.

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 aspect of the present invention.
As the glass plate, a commonly used transparent plate glass can be used. Examples thereof include inorganic glass such as float plate glass, polished plate glass, figured glass, wired glass, lined plate glass, colored plate glass, heat-absorbing glass, heat-reflecting glass, and green glass. Further, an ultraviolet shielding glass having an ultraviolet shielding coating layer formed on the surface of the glass can also be used. Furthermore, organic plastic plates such as polyethylene terephthalate, polycarbonate, and polyacrylate can also be used.
Two or more types of glass plates may be used as the glass plate. Examples thereof include laminated glass obtained by laminating the interlayer film for laminated glass of the present invention between a transparent float plate glass and a colored glass plate such as green glass. Moreover, 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 a nip roll method.
In the nip roll method, a laminate in which an interlayer film for laminated glass is laminated between at least two glass plates is conveyed using a conveyor, and the laminate is passed through a heating zone to be heated to a constant temperature. After that, air remaining between the glass and the intermediate film is removed through nip rolls while being hot-pressed to reduce the air between the intermediate film and the glass of the laminate and to adhere them.
When the laminate is conveyed using a conveyor, the inclination of the grooved grooves of the interlayer film for laminated glass of the present invention should be 55° or less with respect to the flow direction of the conveyor. is preferred. As a result, it is possible to prevent the glass and the interlayer film for laminated glass from being displaced in the laminate during movement by a conveyer, and high production efficiency can be achieved. The inclination of the scored line-shaped concave portions of the interlayer film for laminated glass of the present invention when conveyed using a conveyor is more preferably 45° or less, more preferably 25° or less, with respect to the flow direction of the conveyor. is more preferred.

According to the present invention, an intermediate film for laminated glass that can exhibit high deaeration even by a nip roll method and can produce laminated glass with high visibility without generating air bubbles, and the interlayer film for laminated glass is used. Laminated glass can be provided.

EXAMPLES The aspects of the present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
(Preparation of resin composition for protective layer)
Polyvinyl butyral obtained by acetalizing polyvinyl alcohol with an average degree of polymerization of 1700 with n-butyraldehyde (acetyl group content 1 mol%, butyral group content 69 mol%, hydroxyl group content 30 mol%) per 100 parts by mass Then, 36 parts by mass of triethylene glycol-di-2-ethylhexanoate (3GO) was added as a plasticizer. Furthermore, a mixture of magnesium 2-ethylbutyrate and magnesium acetate (1:1 in mass ratio) was added as an adhesion regulator so that the magnesium content was 50 ppm. The mixture was sufficiently kneaded with a mixing roll to obtain a protective layer resin composition.

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

(Preparation of interlayer film for laminated glass)
The obtained resin composition for intermediate layer and the resin composition for protective layer are co-extruded using a co-extruder to form a first protective layer comprising the resin composition for protective layer and the resin composition for intermediate layer. and a second protective layer made of the protective layer resin composition were laminated in this order to obtain an interlayer film for laminated glass having a three-layer structure.
In the interlayer film for laminated glass obtained after the provision of unevenness, the cross-sectional shape in the thickness direction of the first protective layer is wedge-shaped, the maximum thickness is 525 μm, the minimum thickness is 350 μm, and the cross-sectional shape in the thickness direction of the intermediate layer is wedge-shaped. The thickness is 150 μm, the minimum thickness is 100 μm, the second protective layer has a wedge-shaped cross section in the thickness direction, the maximum thickness is 525 μm, the minimum thickness is 350 μm, the entire intermediate film has a wedge-shaped cross section in the thickness direction, and the maximum thickness is 1200 μm. Extrusion conditions were set so that the minimum thickness was 800 μm.

First, as the first step, the surface of the iron roll is given 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 part after grinding. A pair of rollers having the same shape, which has coarser main embossing and finer sub-embossing, was used as a device for transferring random unevenness to both surfaces of the resulting interlayer film for laminated glass. At this time, the temperature of the intermediate film for laminated glass was 80° C., the temperature of the roll was 145° C., the line speed was 10 m/min, and the press line pressure was 10 to 200 kN/m.
In the second step, a pair of rolls consisting of a metal roll whose surface has been engraved using a triangular oblique mill and a rubber roll having a JIS hardness of 65 to 75 are used as a device for transferring uneven shapes. The intermediate film for glass is passed through this uneven shape transfer device, and unevenness is imparted on one surface of the intermediate film for laminated glass, in which groove-shaped (ruled-line) recesses with continuous bottoms are formed in parallel at regular intervals. bottom. At this time, the temperature of the intermediate film for laminated glass was 70° C., the roll temperature was 145° C., the line speed was 10 m/min, and the press line pressure was 5 to 100 kN/m.

(Evaluation of unevenness of interlayer film for laminated glass)
The interval Sm between the grooved grooves, the radius of rotation R, and the roughness Rz of the grooved grooves on the surface of the obtained interlayer film for laminated glass were measured according to JIS B-0601 (1994). The measurement direction was perpendicular to the ruled line, cutoff value = 2.5 mm, reference length = 2.5 mm, evaluation length = 12.5 mm, stylus tip radius = 2 μm, tip angle = 60. ° and measurement speed = 0.5 mm/s.
In addition, the interval between the grooved grooves was measured using an optical microscope ("BS-D8000III" manufactured by SONIC), and the surface of the interlayer film for laminated glass was observed at five locations in an observation range of 20 mm × 20 mm. , and then the average of the shortest distances between the bottoms of adjacent recesses was calculated.
In addition, the intermediate film for laminated glass is cut using a single-edged razor (FAS-10, manufactured by Feather Safety Razor Co., Ltd.) in a direction perpendicular to the direction of the grooved recesses and parallel to the film thickness direction. As shown, the razor was cut by extruding in a direction parallel to the thickness direction without sliding the razor in the vertical direction, and the cross section was observed using a microscope ("DSX-100" manufactured by Olympus). The above cross section is photographed at a measurement magnification of 208 times, and the photographed image is enlarged to 50 μm / 20 mm, and a circle inscribed in the bottom of the grooved groove is drawn. was determined (that is, radius of gyration R). The Rz of the film surface after the first step was 15 μm.
Table 1 shows the measured values of unevenness on the front and back surfaces of the interlayer film for laminated glass.

(Measurement of plasticizer content)
After the laminated glass was produced, it was allowed to stand for 4 weeks under an environment with a temperature of 25° C. and a humidity of 30%. After that, 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 were cut in the thickness direction, left to stand for 2 hours in an environment with a temperature of 25° C. and a humidity of 30%, then a finger or a machine was inserted between the protective layer and the sound insulation layer, The protective layer and the sound insulation layer were peeled off under an environment of 25° C. temperature and 30% humidity to obtain 10 g rectangular measurement samples for each. After extracting the plasticizer from the measurement sample with diethyl ether for 12 hours using a Soxhlet extractor, the plasticizer in the measurement sample was quantified to determine the plasticizer content in the protective layer and the intermediate layer.

(Examples 2-8, Comparative Examples 1-3)
The acetyl group content, butyral group content, and hydroxyl group content of the polyvinyl butyral used are changed as shown in Table 1, and the shape of the unevenness to be imparted is changed by changing the shape of the embossing roll and the triangular oblique line roll in the first step. However, the cross-sectional shape in the thickness direction, the minimum thickness, the maximum thickness, and the wedge angle of the first protective layer, the intermediate layer, the second protective layer, and the intermediate film as a whole were changed to Tables 1 to 3, except that they were 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 of unevenness on the front and back surfaces of the interlayer films 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 preliminary pressure bonding 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 subsequent operations.
The obtained intermediate film for laminated glass was vertically placed so that the center of the glass was located 30 cm from the thicker end of the laminated glass, and the horizontal direction of the clear glass plate was parallel to the flow direction of the film. An interlayer film for laminated glass was sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction was parallel to the width direction of the film to form a laminate. nip rolls (roll pressure 2 kgf/cm ² ) to obtain a laminate. Further, the laminate is passed through an infrared oven while being conveyed by a roller conveyer, heated to a surface temperature of 50° C., and then secondarily degassed by a second nip roll (roll pressure 4 kgf/cm ² ) and laminated. got a body
The obtained laminate was further placed on a roller conveyor and conveyed, passed through an infrared oven to heat the laminate so that the glass surface temperature of the laminate reached 85 ° C., and then passed through a third nip roll (roll pressure 4 kgf / cm ² ) to remove air remaining between the glass plate and the intermediate film while performing tertiary degassing to complete the pre-press bonding. The gap between the nip rolls was 1 mm narrower than the average thickness of the laminate, and the peripheral speed of the nip rolls was 5 m/min. Tables 1 to 3 show the angles between the grooved lines formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

The laminated body that had been preliminarily press-bonded was immersed in liquid nitrogen and sufficiently cooled to separate the glass so that no glass remained on the surface of the intermediate film, thereby obtaining an intermediate film sheet. After the resulting interlayer sheet was allowed to stand at 23° C. and 30 RH% for 1 hour, the surface of the interlayer sheet was measured with a three-dimensional surface profiler (Contour GT-K, manufactured by Bulker AXS) to determine the remaining embossed shape. was measured. The measurement of the embossed shape by the three-dimensional surface shape measuring machine was performed within 24 hours.
Measurement points were 20 points within an area 3 cm away from the left and right glass edges between 10 and 20 cm from the edge of the glass in the traveling direction when conveyed by a roller conveyer. A field of view for measurement was 1.3 mm×1.3 mm.
From the obtained three-dimensional shape, the volume of the remaining groove shape was measured by "Multivision analysis" of the analysis software attached to the three-dimensional surface profile measuring machine. , the "ZeroLevel" condition in the Multivision analysis conditions was set as "BackGround" by adjusting the value of the "By Threshold" item.
The average groove volume per area was calculated, and when the average of 20 measured points exceeded ^1.5 μm ³ /μm ² (= μm), “x” was given ^. 5 μm ³ /μm ² (=μm) or less was evaluated as “◯”, and less than 1.0 μm ³ /μm ² (=μm) was 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 in 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 subsequent operations.
The obtained intermediate film for laminated glass was vertically placed so that the center of the glass was located 30 cm from the thicker end of the laminated glass, and the horizontal direction of the clear glass plate was parallel to the flow direction of the film. An interlayer film for laminated glass was sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction was parallel to the width direction of the film to form a laminate. nip rolls (roll pressure 2 kgf/cm ² ) to obtain a laminate. Further, the laminate is passed through an infrared oven while being conveyed by a roller conveyer, heated to a surface temperature of 50° C., and then secondarily degassed by a second nip roll (roll pressure 4 kgf/cm ² ) and laminated. got a body

The obtained laminate was further placed on a roller conveyor and conveyed, passed through an infrared oven to heat the laminate so that the glass surface temperature of the laminate reached 85 ° C., and then passed through a third nip roll (roll pressure 4 kgf / cm ² ) to remove air remaining between the glass plate and the intermediate film while performing tertiary degassing to complete the pre-press bonding. The gap between the nip rolls was 1 mm narrower than the average thickness of the laminate, and the peripheral speed of the nip rolls was 5 m/min. Tables 1 to 3 show the angles between the grooved lines formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

(3) Evaluation of Foaming in 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 subsequent operations.
The obtained intermediate film for laminated glass was vertically placed so that the center of the glass was located 30 cm from the thicker end of the laminated glass, and the horizontal direction of the clear glass plate was parallel to the flow direction of the film. An interlayer film for laminated glass was sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction was parallel to the width direction of the film to form a laminate. nip rolls (roll pressure 2 kgf/cm ² ) to obtain a laminate. Further, the laminate is passed through an infrared oven while being transported by a roller conveyor, heated to a surface temperature of 70° C., and then secondarily degassed by a second nip roll (roll pressure: 4 kgf/cm ² ) and laminated. got a body
The gap between the nip rolls was 1 mm narrower than the average thickness of the laminate, and the peripheral speed of the nip rolls was 5 m/min. Tables 1 to 3 show the angles between the grooved lines formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

(4) Evaluation of Foaming in 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 subsequent operations.
The obtained intermediate film for laminated glass was vertically placed so that the center of the glass was located 30 cm from the thicker end of the laminated glass, and the horizontal direction of the clear glass plate was parallel to the flow direction of the film. An interlayer film for laminated glass was sandwiched between two clear glass plates (length 15 cm x width 30 cm x thickness 2.5 mm) so that the direction was parallel to the width direction of the film to form a laminate. nip rolls (roll pressure 2 kgf/cm ² ) to obtain a laminate. Further, the laminate is passed through an infrared oven while being transported by a roller conveyor, heated to a surface temperature of 60° C., and then secondarily degassed by a second nip roll (roll pressure: 4 kgf/cm ² ) and laminated. got a body
The gap between the nip rolls was 1 mm narrower than the thickness of the laminate, and the peripheral speed of the nip rolls was 5 m/min. Tables 1 to 3 show the angles between the grooved lines formed on the surface of the interlayer film for laminated glass and the flow direction of the conveyor.

The laminate obtained under the conditions 1 to 3 for evaluation of foaming of laminated glass was maintained at an internal pressure of 13 atm and an internal temperature of 140°C for 20 minutes using an autoclave, and then the internal temperature was raised to 40°C. After cooling to , the pressure was released to 1 atm to produce a laminated glass.
Furthermore, after storing the laminated glass in an oven at 140° C. for 2 hours, it was taken out of the oven and left to cool for 3 hours, after which the appearance of the laminated glass was visually observed. For each 20 sheets, the number of sheets in which foaming (bubbles) occurred between the glass sheet 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. A case where the number of bubbles was 5 or less was evaluated as "good", and a case where the number of bubbles was 6 or more was evaluated as "poor".

<Evaluation by vacuum degassing method>
(Evaluation of degassing property after pre-press bonding by vacuum bag method)
The obtained interlayer film for laminated glass was sandwiched between two clear glass plates (15 cm long×15 cm wide×2.5 mm thick), and the protruding portion was cut off to obtain a laminate. The obtained laminate was preheated in an oven until the surface temperature of the glass reached 50° C., then transferred into a rubber bag, connected to a vacuum vacuum machine, and held under reduced pressure of −600 mmHg while being heated. After heating so that the temperature of the laminate (preliminary press-bonding temperature) reached 90° C. for 18 minutes, the pressure was returned to atmospheric pressure to complete the preliminary press-bonding, thereby obtaining a laminate after preliminary degassing.

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 laminate after preliminary degassing was measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory).
The measurement positions were the central part where two diagonal lines of the pre-deaerated laminate intersect, and the four points diagonally 5.6 cm away from each vertex of the pre-deaerated laminate. Tp.
Before the measurement, a sample was cut out from the laminate into a size within a range that does not affect the measurement value, centering on the above measurement point, and used as a measurement sample.
The decrease in transparency of the laminated glass is caused by insufficient degassing during pre-press bonding. Therefore, the degassing property of the interlayer film for laminated glass can be evaluated more precisely by measuring the visible light transmittance of the laminate after preliminary degassing, rather than evaluating the foamability of the laminated glass.

According to the present invention, an intermediate film for laminated glass that can exhibit high deaeration even by a nip roll method and can produce laminated glass with high visibility without generating air bubbles, and the interlayer film for laminated glass is used. Laminated glass can be provided.

Claims (4)

At least one surface has a large number of recesses and a large number of protrusions, the recesses have a groove shape with a continuous bottom, the adjacent recesses are arranged in parallel and regularly, and An interlayer film for laminated glass having a random uneven shape,
A ratio (R/Sm×100) of the radius of gyration R of the bottom of the groove-shaped recesses with continuous bottoms to the interval Sm between the groove-shaped recesses with continuous bottoms is 15% or more,
having one end and the other end on the opposite side of the one end, the thickness of the other end being greater than the thickness of the one end;
An intermediate film for laminated glass, wherein the roughness Rz of the groove-shaped recesses with continuous bottoms is 10 μm or more and 80 μm or less. 2. The interlayer film for laminated glass according to claim 1, wherein the groove-shaped concave portion with a continuous bottom has a bottom portion with a radius of gyration R of 20 to 250 μm. 3. The interlayer film for laminated glass according to claim 1, wherein an interval Sm between groove-shaped recesses having continuous bottoms is 100 to 400 μm. 4. Laminated glass, wherein the interlayer film for laminated glass according to claim 1, 2 or 3 is laminated between a pair of glass plates.