Interlayer film for laminated glass and laminated glass
阅读说明：本技术 夹层玻璃用中间膜及夹层玻璃 (Interlayer film for laminated glass and laminated glass ) 是由 安原骏也 盛美智子 近藤匡弥 木户浩二 中山和彦 于 2019-09-26 设计创作，主要内容包括：本发明提供能够提供抑制了透视变形产生的夹层玻璃的夹层玻璃用中间膜、使用了该夹层玻璃用中间膜的夹层玻璃、以及该夹层玻璃用中间膜的制造方法。本发明是一种夹层玻璃用中间膜的宽度方向的厚度的最大曲率为0.010m~(-1)以下的夹层玻璃用中间膜。(The invention provides an interlayer film for laminated glass, which can provide laminated glass with the generation of perspective deformation suppressed, laminated glass using the interlayer film for laminated glass, and a method for manufacturing the interlayer film for laminated glass. The present invention is an intermediate film for laminated glass, which has a maximum curvature of 0.010m in the thickness in the width direction ‑1 The following interlayer film for laminated glass.)
1. An interlayer film for laminated glass, characterized in that the maximum curvature of the thickness of the interlayer film in the width direction of the laminated glass is 0.010m-1The following.
2. The interlayer film for laminated glass according to claim 1, wherein the maximum value of the thickness drop in the width direction measured in a 150mm interval of the interlayer film for laminated glass is 15 μm or less.
3. A laminated glass comprising the interlayer film for laminated glass according to claim 1 or 2 laminated between a pair of glass plates, wherein the maximum curvature of the thickness of the interlayer film for laminated glass in the width direction of the laminated glass is 0.004m-1The following.
4. A laminated glass comprising the interlayer film for laminated glass according to claim 1 or 2 laminated between a pair of glass plates, wherein the maximum curvature of the thickness of the laminated glass in the width direction is 0.010m-1The following.
5. The laminated glass according to claim 4, wherein the maximum curvature of the thickness of the laminated glass in the width direction is 0.003m-1The following.
6. A method for producing an interlayer film for a laminated glass, which is the method for producing an interlayer film for a laminated glass according to claim 1 or 2,
the method comprises a step of using a lip method in which unevenness is imparted to the surface of the interlayer film for laminated glass while a raw material resin composition is extruded from an extruder,
as the die head of the extruder, a die head having a straightness of 4 μm or less between 1000mm in the width direction and an unevenness of 2 μm or less in a section of 80mm in the width direction was used.
7. The method for producing an interlayer film for laminated glass according to claim 6, wherein a press roll having a cylindricity of 4 μm or less is used as the press roll.
Technical Field
The present invention relates to an interlayer film for laminated glass that can provide laminated glass in which occurrence of perspective distortion is suppressed, and to laminated glass using the interlayer film for laminated glass.
Background
Laminated glasses obtained by sandwiching and bonding an interlayer film for laminated glasses containing a thermoplastic resin such as plasticized polyvinyl butyral between 2 glass sheets are widely used as window glasses for automobiles, airplanes, buildings, and the like.
As an interlayer film for laminated glass, not only an interlayer film for laminated glass having a single layer structure comprising only 1 resin layer but also an interlayer film for laminated glass having a multilayer structure comprising a laminate of 2 or more resin layers has been proposed. By having the 1 st resin layer and the 2 nd resin layer as a multilayer structure, and the 1 st resin layer and the 2 nd resin layer have different properties, an interlayer film for laminated glass having various performances which are difficult to realize with only 1 layer can be provided.
For example, patent document 1 discloses an interlayer film for a laminated glass having a 3-layer structure including a sound-insulating layer and 2 protective layers sandwiching the sound-insulating layer. The interlayer film for laminated glass of patent document 1 has a sound-insulating layer containing a polyvinyl acetal resin having excellent affinity with a plasticizer and a large amount of a plasticizer, and thus exhibits excellent sound-insulating properties. On the other hand, the protective layer prevents a large amount of plasticizer contained in the sound-insulating layer from bleeding out to deteriorate the adhesion between the interlayer film and the glass.
Various optical properties are required for laminated glass depending on the application. For example, when the laminated glass is used for a windshield of an automobile, it is important to reduce the perspective distortion. The perspective distortion is a phenomenon in which an image formed in the front is visually distorted when the laminated glass is placed at an angle like the windshield, and if the perspective distortion exists, the visibility of the driver is reduced, which may cause a serious obstacle to driving. However, the cause of the occurrence of the perspective distortion has not been sufficiently clarified so far, and it is difficult to provide a laminated glass in which the occurrence of the perspective distortion is suppressed.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2007-331959
Disclosure of Invention
Problems to be solved by the invention
In view of the above-described situation, an object of the present invention is to provide an interlayer film for laminated glass that can provide a laminated glass in which occurrence of perspective distortion is suppressed, and a laminated glass using the interlayer film for laminated glass.
Means for solving the problems
The present invention provides an interlayer film for a laminated glass, wherein the maximum curvature of the thickness of the interlayer film in the width direction of the laminated glass is 0.010m-1The following.
The present invention is described in detail below.
The present inventors have studied the cause of the occurrence of the see-through distortion in the laminated glass. As a result, it was found that the laminated glass causes a perspective distortion by condensing or diffusing light like a lens at a portion where the thickness of the laminated glass in the width direction locally changes.
The present inventors have next studied the cause of occurrence of a local thickness change in the width direction of a laminated glass which causes a see-through distortion. As a result, they found that the reason is an interlayer film for laminated glass.
In a process for producing a laminated glass, for example, in the rubber bag method, first, an interlayer film for a laminated glass unwound from a roll is cut into an appropriate size, the interlayer film for a laminated glass is sandwiched between at least 2 glass plates to obtain a laminate, and the obtained laminate is put into a rubber bag and subjected to suction under reduced pressure, and is subjected to preliminary pressure bonding while degassing air remaining between the glass plates and the interlayer film. Subsequently, for example, the pressure is heated and pressurized in an autoclave to perform main pressure bonding. In the pinch roll method, for example, a laminate obtained by sandwiching an interlayer film for a laminated glass between at least 2 glass plates is passed through a heating zone while being conveyed by a conveyor, heated to a certain temperature, and then passed through pinch rolls. Thus, the air remaining between the glass and the interlayer is scraped off and removed, and the interlayer of the laminate is thermally pressure bonded to reduce the air between the glass and the interlayer, thereby performing the pre-pressure bonding. The final adhesion was performed in an autoclave at high temperature and high pressure with the air between the obtained laminates reduced.
When a laminated glass is produced by such a method, if the interlayer film for laminated glass has a local thickness variation in the width direction, the laminated glass is bent along the interlayer film for laminated glass, and the resulting laminated glass also has a local thickness variation in the width direction, and therefore, see-through distortion occurs.
The present inventors have further conducted extensive studies and as a result, have found that the maximum curvature of the thickness in the width direction is set to 0.010m by controlling the local thickness change in the width direction of the interlayer film for laminated glass-1As described below, the present inventors have provided a laminated glass in which occurrence of perspective distortion is suppressed, and have completed the present invention.
The interlayer for a laminated glass of the present invention has a maximum curvature of 0.010m in the thickness in the width direction of the interlayer for a laminated glass-1The following. This makes it possible to provide a laminated glass in which occurrence of perspective distortion is suppressed. The maximum curvature of the thickness of the interlayer film for laminated glass in the film direction is preferably 0.008m-1Hereinafter, more preferably 0.007m-1The following.
The lower limit of the maximum curvature of the thickness of the interlayer film for a laminated glass is not particularly limited, but is preferably 0.000m when the 4 th position after decimal point is rounded-1The above.
The interlayer film for laminated glass of the present invention preferably has a maximum value of thickness drop in the width direction measured in a 150mm interval of 15 μm or less. This can provide a laminated glass in which the occurrence of perspective distortion is further suppressed. The maximum value of the thickness difference in the width direction of the interlayer film for laminated glass is more preferably 8 μm or less.
In the present specification, the maximum value of the thickness drop in the width direction measured in the interval of 150mm of the interlayer film for laminated glass means the difference between the maximum value and the minimum value of the thickness measurement value in the interval of 150 mm.
In the present specification, the width direction of the interlayer film for laminated glass means the direction of the same plane orthogonal to the flow direction of the film in the production of the interlayer film for laminated glass. Here, the flow direction during production refers to a direction in which the raw material resin composition is extruded from an extruder during production of the interlayer film for laminated glass.
The flow direction in the production of the interlayer film for laminated glass can be confirmed, for example, by the following method. That is, it can be confirmed that the interlayer film for a laminated glass has a larger shrinkage rate in the parallel direction and the perpendicular direction of the film as the flow direction after being kept in a constant temperature bath at 140 ℃ for 30 minutes. The winding direction of the roll of interlayer film for laminated glass can be confirmed. This is because the roll of the interlayer film for laminated glass is wound in the film flow direction during production of the interlayer film for laminated glass, and therefore the winding direction of the roll is the same as the film flow direction during production of the interlayer film for laminated glass.
The method for measuring the maximum curvature of the thickness and the maximum value of the thickness drop in the width direction of the interlayer film for laminated glass according to the present invention will be described in detail with reference to fig. 1.
In fig. 1(a), first, an interlayer film 1 for laminated glass is drawn from a roll 2. In this case, the drawing direction is a flow direction in the production of the interlayer film for laminated glass, and a direction of the same plane orthogonal to the flow direction is a width direction. The drawn interlayer film for laminated glass was cut at a position of 70cm or more in the flow direction to obtain a test sample of 70cm × film width (usually 1 m). The test specimens were placed on a flat surface at 20 ℃ and 30 RH% or less and subjected to measurement after 24 hours of curing. After curing, the thickness was measured continuously at a speed of 1.5m/min from one end to the other end in the width direction of the test specimen using a micrometer (e.g., a wide range electronic micrometer KG601B, manufactured by anli electric corporation), and the thickness was recorded at a pitch of 0.4 mm. The thickness was measured under the conditions of 20 ℃ and 30 RH% or less.
Next, based on the obtained data of the thickness in the width direction, the maximum curvature of the thickness in the width direction of the interlayer film for laminated glass is calculated.
That is, based on the obtained data of the thickness in the width direction, the data (raw data generated every 0.4 mm) obtained by performing measurement while moving 0.4mm from the end of the measurement point each time is subjected to the simple moving averaging processing in the 40mm section. After the moving averaging process, 3-degree polynomial approximations using the least square method in each 30mm interval were created while shifting the initial values by 0.4mm each time. Using a polynomial approximated function f (x), the curvature of the center within the interval is calculated. The curvature is calculated by the following formula (1).
Then, the maximum value of the curvature calculated in each section was obtained and used as the maximum curvature of the thickness of the test sample in the width direction.
[ mathematical formula 1]
On the other hand, the maximum value of the thickness difference in the width direction of the interlayer film for laminated glass is calculated based on the obtained data of the thickness in the width direction.
That is, based on the obtained data of the thickness in the width direction, the maximum drop height (the difference between the point of maximum thickness and the point of minimum thickness) in each 150mm interval was obtained while moving 0.4mm from the end of the measurement point. The maximum difference in height in each 150mm section in the width direction was calculated, and the maximum value among these was taken as the maximum value of the thickness difference in the test sample.
The interlayer film for laminated glass of the present invention preferably contains a thermoplastic resin.
Examples of the thermoplastic resin include polyvinylidene fluoride, polytetrafluoroethylene, a vinylidene fluoride-hexafluoropropylene copolymer, polytrifluoroethylene, an acrylonitrile-butadiene-styrene copolymer, a polyester, a polyether, a polyamide, a polycarbonate, a polyacrylate, a polymethacrylate, polyvinyl chloride, polyethylene, polypropylene, polystyrene, a polyvinyl acetal, an ethylene-vinyl acetate copolymer, and the like. Among them, polyvinyl acetal is preferable in terms of ease of production of an interlayer film for laminated glass that satisfies the expansion ratio in the width direction and the shrinkage ratio in the flow direction.
The polyvinyl acetal can be produced, for example, by acetalizing polyvinyl alcohol (PVA) with an aldehyde. The saponification degree of PVA is usually in the range of 70 to 99.9 mol%.
The polymerization degree of polyvinyl alcohol (PVA) for obtaining the polyvinyl acetal is preferably 200 or more, and more preferably 500 or more. The polymerization degree of the polyvinyl alcohol (PVA) is more preferably 1700 or more, particularly preferably 2000 or more, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, still more preferably less than 3000, and particularly preferably 2800 or less. The polyvinyl acetal is preferably a polyvinyl acetal resin obtained by acetalizing a PVA having a polymerization degree of not less than the lower limit and not more than the upper limit. If the polymerization degree is not less than the lower limit, the penetration resistance of the laminated glass is further improved. If the polymerization degree is not more than the upper limit, the intermediate film can be easily formed.
The polymerization degree of PVA indicates the average polymerization degree. The average polymerization degree was determined by a method in accordance with JIS K6726 "polyvinyl alcohol test method". As the aldehyde, an aldehyde having 1 to 10 carbon atoms is usually preferably used. Examples of the aldehyde having 1 to 10 carbon atoms include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexanal, n-octylaldehyde, n-nonanal, n-decanal, benzaldehyde, and the like. Among them, n-butyraldehyde, n-hexanal or n-valeraldehyde is preferable, and n-butyraldehyde is more preferable. The above aldehyde may be used alone in 1 kind, or 2 or more kinds may be used in combination.
The polyvinyl acetal resin contained in the interlayer film for laminated glass of the present invention is preferably a polyvinyl butyral resin. By using the polyvinyl butyral resin, the interlayer film further improves the weather resistance and the like of 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 generally used for an interlayer film for a laminated glass, and examples thereof include organic plasticizers such as monobasic organic acid esters and polybasic organic acid esters, phosphoric acid plasticizers such as organic phosphoric acid compounds and organic phosphorous acid compounds, and the like.
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, and diethylene glycol di-n-heptanoate. 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-2-ethylhexanoate is more preferably contained.
In the interlayer film for laminated glass of the present invention, the content of the plasticizer with respect to the thermoplastic resin is not particularly limited. The content of the plasticizer is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, further preferably 35 parts by mass or more, preferably 80 parts by mass or less, more preferably 60 parts by mass or less, and further preferably 50 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin. If the content of the plasticizer is not less than the lower limit, the penetration resistance of the laminated glass is further improved. If the content of the plasticizer is not more than the upper limit, the transparency of the interlayer film is further improved.
The interlayer film for laminated glass of the present invention preferably contains an adhesion modifier.
As the adhesion regulator, for example, an alkali metal salt or an alkaline earth metal salt is preferably used. Examples of the adhesion regulator include salts of potassium, sodium, magnesium, and the like.
Examples of the acid constituting the salt include organic acids of carboxylic acids such as octanoic acid, hexanoic 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 contain additives such as 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 reflecting agent, a heat ray absorbing agent, an anti-blocking agent, an antistatic agent, and a colorant including a pigment or a dye, as required.
The interlayer film for laminated glass of the present invention may have a single-layer structure composed of only 1 resin film, or may have a multilayer structure in which 2 or more resin layers are laminated.
When the interlayer film for a laminated glass of the present invention has a multilayer structure, the interlayer film for a laminated glass having various performances which are difficult to realize with only 1 layer can be provided by having the 1 st resin layer and the 2 nd resin layer as the 2 or more resin layers and having different properties between the 1 st resin layer and the 2 nd resin layer. The multilayer structure may have 3 or more layers, 4 or more layers, or 5 or more layers.
When the interlayer film for laminated glass of the present invention has a multilayer structure, for example, in order to improve the sound insulation property of laminated glass, an interlayer film for laminated glass (hereinafter, also referred to as "sound insulation interlayer film") having excellent sound insulation property, which is obtained by sandwiching the sound insulation layer by 2 protective layers with the 1 st resin layer as a protective layer and the 2 nd resin layer as a sound insulation layer, is exemplified. The 1 st resin layer or the 2 nd resin layer may be a heat insulating layer containing a heat insulating agent, or the 1 st resin layer or the 2 nd resin layer may be a light emitting layer containing a light emitting material.
Hereinafter, the sound-insulating interlayer will be described in more detail.
In the sound-insulating interlayer, the sound-insulating layer has a function of imparting sound-insulating properties.
The sound-insulating layer preferably contains polyvinyl acetal X and a plasticizer.
The polyvinyl acetal X can be produced by acetalizing polyvinyl alcohol with an aldehyde. The polyvinyl acetal X is preferably an acetal of polyvinyl alcohol. The polyvinyl alcohol is generally obtained by saponifying polyvinyl acetate.
The polymerization degree of the polyvinyl alcohol preferably has a lower limit of 200 and an upper limit of 5000. The penetration resistance of the resulting sound-insulating interlayer can be improved by setting the polymerization degree of the polyvinyl alcohol to 200 or more, and the moldability of the sound-insulating layer can be ensured by setting the polymerization degree of the polyvinyl alcohol to 5000 or less. The polymerization degree of the polyvinyl alcohol has a more preferable lower limit of 500 and a more preferable upper limit of 4000.
The number of carbon atoms of the aldehyde for acetalizing the polyvinyl alcohol is preferably 4 as the lower limit and 6 as the upper limit. When the number of carbon atoms of the aldehyde is 4 or more, a sufficient amount of the plasticizer can be stably contained, and excellent sound insulation performance can be exhibited. In addition, the bleed-out of the plasticizer can be prevented. When the number of carbon atoms of the aldehyde is 6 or less, the polyvinyl acetal X can be easily synthesized, 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 and n-valeraldehyde.
The preferable upper limit of the amount of the hydroxyl group in the polyvinyl acetal X is 30 mol%. When the amount of the hydroxyl group of the polyvinyl acetal X is 30 mol% or less, the plasticizer can be contained in an amount necessary for exhibiting sound-insulating properties, and bleeding of the plasticizer can be prevented. The amount of the hydroxyl group in the polyvinyl acetal X is preferably up to 28 mol%, more preferably up to 26 mol%, even more preferably up to 24 mol%, more preferably up to 10 mol%, more preferably up to 15 mol%, and even more preferably up to 20 mol%.
The hydroxyl group content of the polyvinyl acetal X is a value represented by a percentage (mol%) of a mole fraction obtained by dividing the amount of ethylene groups to which hydroxyl groups are bonded by the total ethylene amount of the main chain. The amount of the hydroxyl group-bonded ethylene group can be determined, for example, by measuring the amount of the hydroxyl group-bonded ethylene group of the polyvinyl acetal X by a method in accordance with JIS K6728 "polyvinyl butyral test method".
The amount of the acetal group in the polyvinyl acetal X preferably has a lower limit of 60 mol% and an upper limit of 85 mol%. When the acetal group amount of the polyvinyl acetal X is 60 mol% or more, the water repellency of the sound-insulating layer can be improved, and the plasticizer can be contained in an amount necessary for exhibiting sound-insulating properties, whereby bleeding or whitening of the plasticizer can be prevented. By setting the amount of acetal groups of the polyvinyl acetal X to 85 mol% or less, the polyvinyl acetal X can be easily synthesized, and productivity can be ensured. The amount of acetal groups can be determined by measuring the amount of acetal groups bonded to the polyvinyl acetal X by a method in accordance with JIS K6728 "polyvinyl butyral test method".
The amount of the acetyl group in the polyvinyl acetal X preferably has a lower limit of 0.1 mol% and an upper limit of 30 mol%. When the acetyl group content of the polyvinyl acetal X is 0.1 mol% or more, a plasticizer can be contained in an amount necessary for exhibiting sound-insulating properties, and bleeding can be prevented. Further, when the acetyl group content of the polyvinyl acetal X is 30 mol% or less, the hydrophobicity of the sound-insulating layer can be improved and whitening can be prevented. The lower limit of the amount of the acetyl group is more preferably 1 mol%, the lower limit is more preferably 5 mol%, the lower limit is particularly preferably 8 mol%, the upper limit is more preferably 25 mol%, and the upper limit is more preferably 20 mol%. The acetyl group amount is a value represented by a percentage (mol%) of a molar fraction obtained by dividing a value obtained by subtracting the amount of the acetal group-bonded ethylene group and the amount of the hydroxyl group-bonded ethylene group from the total amount of ethylene groups in the main chain by the total amount of ethylene groups in the main chain.
In particular, the polyvinyl acetal X is preferably polyvinyl acetal having an acetyl group amount of 8 mol% or more, or polyvinyl acetal having an acetyl group amount of less than 8 mol% and an acetal group amount of 68 mol% or more, in view of enabling the sound-insulating layer to easily contain a plasticizer in an amount necessary for exhibiting sound-insulating properties.
The lower limit of the content of the plasticizer in the sound-insulating layer is preferably 45 parts by mass and the upper limit thereof is preferably 80 parts by mass with respect to 100 parts by mass of the polyvinyl acetal X. The interlayer film for a laminated glass can exhibit high sound-insulating properties by containing 45 parts by mass or more of the plasticizer, and can prevent the occurrence of bleed-out of the plasticizer and the deterioration of transparency and adhesiveness. The lower limit of the content of the plasticizer is more preferably 50 parts by mass, the lower limit is more preferably 55 parts by mass, the upper limit is more preferably 75 parts by mass, and the upper limit is more preferably 70 parts by mass.
When the sound insulating layer has a rectangular cross-sectional shape in the thickness direction, the preferable lower limit of the thickness is 50 μm. By setting the thickness of the sound insulating layer to 50 μm or more, sufficient sound insulating properties can be exhibited. The lower limit of the thickness of the sound-insulating layer is more preferably 70 μm, and still more preferably 80 μm. The upper limit is not particularly limited, and is preferably 150 μm in consideration of the thickness of the interlayer film for laminated glass.
The soundproof layer may have the following shape: the optical fiber connector has one end and the other end located on the opposite side of the one end, and the thickness of the other end is larger than that of the one end. The soundproof layer preferably has a portion having a wedge-shaped cross section in the thickness direction. In this case, a preferable lower limit of the minimum thickness of the sound-insulating layer is 50 μm. By setting the minimum thickness of the sound insulating layer to 50 μm or more, sufficient sound insulating properties can be exhibited. The lower limit of the minimum thickness of the soundproof layer is more preferably 80 μm, and still more preferably 100 μm. The upper limit of the maximum thickness of the sound-insulating layer is not particularly limited, and 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 soundproof layer is 220 μm.
The protective layer has the effect of preventing the interlayer film for laminated glass from being deteriorated in adhesion to glass due to the bleed-out of a large amount of the plasticizer contained in the sound-insulating layer, and imparting penetration resistance to the interlayer film for laminated glass.
The protective layer preferably contains, for example, polyvinyl acetal Y and a plasticizer, and more preferably contains polyvinyl acetal Y having a larger amount of hydroxyl groups than polyvinyl acetal X and a plasticizer.
The polyvinyl acetal Y can be produced by acetalizing polyvinyl alcohol with an aldehyde. The polyvinyl acetal Y is preferably an acetal of polyvinyl alcohol.
The polyvinyl alcohol is generally obtained by saponifying polyvinyl acetate. The polymerization degree of the polyvinyl alcohol preferably has a lower limit of 200 and an upper limit of 5000. The penetration resistance of the interlayer film for laminated glass can be improved by setting the polymerization degree of the polyvinyl alcohol to 200 or more, and the formability of the protective layer can be ensured by setting the polymerization degree of the polyvinyl alcohol to 5000 or less. The polymerization degree of the polyvinyl alcohol has a more preferable lower limit of 500 and a more preferable upper limit of 4000.
The number of carbon atoms of the aldehyde for acetalizing the polyvinyl alcohol is preferably 3 in the lower limit and 4 in the upper limit. When the carbon number of the aldehyde is 3 or more, the penetration resistance of the interlayer film for laminated glass is increased. When the number of carbon atoms of the aldehyde is 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.
The amount of the hydroxyl group in the polyvinyl acetal Y is preferably 33 mol% at the upper limit and 28 mol% at the lower limit. When the amount of the hydroxyl group in the polyvinyl acetal Y is 33 mol% or less, whitening of the interlayer film for a laminated glass can be prevented. When the amount of hydroxyl groups in the polyvinyl acetal Y is 28 mol% or more, the penetration resistance of the interlayer film for a laminated glass is increased.
The amount of the acetal group in the polyvinyl acetal Y preferably has a lower limit of 60 mol% and an upper limit of 80 mol%. By setting the amount of the acetal group to 60 mol% or more, a plasticizer can be contained in an amount necessary to exhibit sufficient penetration resistance. By setting the amount of the acetal group to 80 mol% or less, the adhesion between the protective layer and the glass can be secured. The lower limit of the amount of the acetal group is more preferably 65 mol%, and the upper limit is more preferably 69 mol%.
The preferable upper limit of the acetyl group amount of the polyvinyl acetal Y is 7 mol%. When the acetyl group content of the polyvinyl acetal Y is 7 mol% or less, the hydrophobicity of the protective layer can be increased to prevent whitening. The upper limit of the amount of the acetyl group is more preferably 2 mol%, and the lower limit is preferably 0.1 mol%. The amount of hydroxyl groups, the amount of acetal groups, and the amount of acetyl groups in the polyvinyl acetal Y can be measured by the same method as that for the polyvinyl acetal X.
The lower limit of the content of the plasticizer in the protective layer is preferably 20 parts by mass and the upper limit thereof is preferably 45 parts by mass with respect to 100 parts by mass of the polyvinyl acetal Y. The penetration resistance can be ensured by setting the content of the plasticizer to 20 parts by mass or more, and the bleed-out of the plasticizer can be prevented and the lowering of the transparency and adhesiveness of the interlayer film for laminated glass can be prevented by setting the content of the plasticizer to 45 parts by mass or less. The lower limit of the content of the plasticizer is more preferably 30 parts by mass, the lower limit is more preferably 35 parts by mass, the upper limit is more preferably 43 parts by mass, and the upper limit is more preferably 41 parts by mass. From the viewpoint of further improving the sound-insulating property of the laminated glass, the content of the plasticizer in the protective layer is preferably smaller than the content of the plasticizer in the sound-insulating layer.
From the viewpoint of further improving the sound insulating property of the laminated glass, the amount of hydroxyl groups of the polyvinyl acetal Y is preferably larger than the amount of hydroxyl groups of the polyvinyl acetal X, more preferably 1 mol% or more larger than the amount of hydroxyl groups of the polyvinyl acetal X, further preferably 5 mol% or more larger than the amount of hydroxyl groups of the polyvinyl acetal X, and particularly preferably 8 mol% or more larger than the amount of hydroxyl groups of the polyvinyl acetal X. By adjusting the amount of hydroxyl groups in the polyvinyl acetal X and the polyvinyl acetal Y, the content of the plasticizer in the sound-insulating layer and the protective layer can be controlled, and the glass transition temperature of the sound-insulating layer can be lowered. As a result, the sound insulation of the laminated glass is further improved.
In addition, from the viewpoint of further improving the sound insulating property of the laminated glass, the content of the plasticizer in the sound insulating layer (hereinafter, also referred to as content X) with respect to 100 parts by mass of the polyvinyl acetal X is preferably larger than the content of the plasticizer in the protective layer (hereinafter, also referred to as content Y) with respect to 100 parts by mass of the polyvinyl acetal Y, more preferably larger than the content of the plasticizer in the protective layer with respect to 100 parts by mass of the polyvinyl acetal Y by 5 parts by mass or more, further preferably larger than the content of the plasticizer in the protective layer with respect to 100 parts by mass of the polyvinyl acetal Y by 15 parts by mass or more, and particularly preferably larger than the content of the plasticizer in the protective layer with respect to 100 parts by mass of the polyvinyl acetal Y by 20 parts by mass or more. By adjusting the content X and the content Y, the glass transition temperature of the sound-insulating layer is lowered. As a result, the sound insulation of the laminated glass is further improved.
When the cross-sectional shape of the protective layer is rectangular, the lower limit of the thickness of the protective layer is preferably 200 μm, and the upper limit is preferably 1000 μm. The penetration resistance can be ensured by setting the thickness of the protective layer to 200 μm or more. The lower limit of the thickness of the protective layer is more preferably 300 μm, and the upper limit is more preferably 700 μm.
The protective layer may have the following shape: the optical fiber connector has one end and the other end located on the opposite side of the one end, and the thickness of the other end is larger than that of the one end. The protective layer preferably has a portion having a wedge-shaped cross section in the thickness direction. The thickness of the protective layer is not particularly limited as long as it is adjusted within a range in which the function of the protective layer can be exerted. However, when the protective layer has irregularities, it is preferable to set the thickness to be as thick as possible in order to suppress the transfer of the irregularities to the interface between the protective layer and the sound insulating layer in direct contact therewith. Specifically, the minimum thickness of the protective layer preferably has a lower limit of 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, and in order to ensure the thickness of the sound insulating layer to a degree that sufficient sound insulating properties can be achieved, the upper limit is substantially about 1000 μm, and is preferably 800 μm.
The interlayer film for laminated glass of the present invention may have one end and the other end located on the opposite side of the one end. The one end and the other end are end portions on both sides facing each other in the intermediate film. In the interlayer film for laminated glass of the present invention, the thickness of the other end is preferably larger than the thickness of the one end. By having such a shape that the thickness is different between one end and the other end, the laminated glass using the interlayer film for laminated glass of the present invention can be suitably used as a head-up display, and in this case, the occurrence of double images can be effectively suppressed. The cross-sectional shape of the interlayer film for laminated glass of the present invention may be a wedge shape. If the cross-sectional shape of the interlayer film for laminated glass is a wedge shape, the wedge angle θ of the wedge shape is adjusted according to the mounting angle of the laminated glass, whereby image display in which the occurrence of double images is prevented can be performed in the head-up display. From the viewpoint of further suppressing ghost, the wedge angle θ has a preferred lower limit of 0.1mrad, a more preferred lower limit of 0.2mrad, a further preferred lower limit of 0.3mrad, a preferred upper limit of 1mrad, and a more preferred upper limit of 0.9 mrad. For example, when an interlayer film for laminated glass having a wedge-shaped cross-sectional shape is produced by extrusion molding a resin composition using an extruder, the interlayer film may have a minimum thickness in a region slightly inward from one thin end portion and a maximum thickness in a region slightly inward from one thick end portion. (specifically, a region slightly inside means a region having a distance of 0X to 0.2X from one end of a thick side or a thin side toward the inside when the distance between the one end and the other end is X).
The method for producing the sound-insulating interlayer is not particularly limited, and examples thereof include: and a method of laminating the sound insulating layer and the protective layer after forming the sound insulating layer and the protective layer into a sheet by a general film forming method such as an extrusion method, a rolling method, a pressing method, or the like.
The method for producing the interlayer film for laminated glass of the present invention is not particularly limited, and the interlayer film can be produced by a method in which a raw material resin composition is extrusion-molded from an extruder. Here, by controlling the conditions during extrusion molding, an interlayer film for a laminated glass that satisfies the maximum curvature of the thickness in the width direction and the maximum value of the thickness difference in the width direction can be obtained. Here, when the surface of the interlayer film for laminated glass is embossed, it is difficult to obtain an interlayer film for laminated glass that satisfies the maximum curvature of the thickness in the width direction and the maximum value of the thickness difference in the width direction by using an embossing roller, and therefore, it is preferable to use a lip method in which unevenness is provided by designing the shape of a die head of an extruder.
More specifically, (1) a barrel head having a straightness of 4 μm or less in a width direction of 1000mm and an unevenness of 2 μm or less in a section of 80mm in the width direction is preferably used as the barrel head of the extruder used in the lip method, and (2) a press roll having a cylindricity of 4 μm or less is preferably used as the press roll. By controlling the extrusion conditions as described above, an interlayer film for a laminated glass that satisfies the maximum curvature of the thickness in the width direction and the maximum value of the thickness difference in the width direction can be obtained.
A method for producing an interlayer film for a laminated glass of the present invention is also one of the present invention, and the method for producing an interlayer film for a laminated glass of the present invention includes a step of using a lip method of extruding a raw material resin composition from an extruder and simultaneously providing unevenness to the surface of the interlayer film for a laminated glass, wherein a tip having a straightness of 4 μm or less in a width direction of 1000mm and an unevenness of 2 μm or less in a section of 80mm in the width direction is used as a tip of the extruder.
The interlayer film for laminated glass of the present invention is controlled so that the maximum curvature of the thickness in the width direction is 0.010m by controlling the local thickness variation in the width direction-1Since the adjustment is performed in the following manner, the laminated glass using the same has a small local thickness variation in the width direction. This results in extremely small perspective distortion of the resulting laminated glass.
The degree of perspective distortion can be evaluated by performing a distortion test.
The maximum curvature of the width-directional thickness of the interlayer film for laminated glass in the laminated glass is 0.004m-1The following laminated glass is also one aspect of the present invention as a laminated glass in which the interlayer film for laminated glass of the present invention is laminated between a pair of glass plates. The maximum curvature of the width-direction thickness of the interlayer film for laminated glass in the laminated glass is set to 0.004m-1As a result, the perspective distortion can be further reduced. The maximum curvature of the thickness of the interlayer film for a laminated glass in the width direction of the laminated glass is more preferably 0.003m-1The following.
Width of laminated glassMaximum curvature of thickness in the direction of 0.010m-1The following laminated glass is also one aspect of the present invention as a laminated glass in which the interlayer film for laminated glass of the present invention is laminated between a pair of glass plates. By setting the maximum curvature of the width-direction thickness of the laminated glass itself to 0.010m-1As a result, the perspective distortion can be further reduced. The maximum curvature of the thickness of the laminated glass in the width direction is more preferably 0.003m-1The following.
The width direction of the laminated glass coincides with the width direction of the interlayer film for laminated glass.
As the glass plate, a commonly used transparent plate glass can be used. Examples of the inorganic glass include float glass, polished glass, patterned glass, wired glass, colored glass, heat-ray absorbing glass, heat-ray reflecting glass, and green glass. In addition, an ultraviolet shielding glass having an ultraviolet shielding coating layer formed on the surface of the glass may be used. Further, organic plastic plates such as polyethylene terephthalate, polycarbonate, and polyacrylate can also be used.
As the glass plate, 2 or more kinds of glass plates can be used. An example of the laminated glass is a laminated glass in which the interlayer film for laminated glass of the present invention is laminated between colored glass plates such as a transparent float glass and a green glass. As the glass plate, 2 or more glass plates having different thicknesses may be used.
The method for measuring the maximum curvature of the thickness in the width direction and the maximum value of the thickness difference in the laminated glass of the present invention is substantially the same as the method for measuring the maximum curvature of the thickness in the width direction and the maximum value of the thickness difference in the laminated glass interlayer. The test sample was prepared by cooling the laminated glass at 20 ℃ and 30 RH%.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide an interlayer film for laminated glass that can provide a laminated glass in which the occurrence of perspective distortion is suppressed, a laminated glass using the interlayer film for laminated glass, and a method for producing the interlayer film for laminated glass.
Drawings
Fig. 1 is a schematic view illustrating a method for measuring the maximum curvature of the thickness in the width direction and the maximum value of the thickness difference in the interlayer film for laminated glass.
Fig. 2 is a schematic diagram illustrating a deformation test in the evaluation of examples and comparative examples.
Detailed Description
The mode of the present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
(example 1)
(1) Production of interlayer film for laminated glass
40 parts by mass of a plasticizer, 0.5 part by mass of an ultraviolet-screening agent, and 0.5 part by mass of an antioxidant were added to 100 parts by mass of polyvinyl butyral, and the mixture was sufficiently kneaded by a mixing roll to obtain a resin composition. In the polyvinyl butyral, the content of hydroxyl groups was 30 mol%, the degree of acetylation was 1 mol%, the degree of butyralization was 69 mol%, and the average degree of polymerization was 1700. Triethylene glycol di-2-ethylhexanoate (3GO) was used as a plasticizer. As the ultraviolet-screening agent, 2- (2 '-hydroxy-3' -tert-butyl-5-methylphenyl) -5-chlorobenzotriazole (manufactured by BASF corporation, "Tinuvin 326") was used. As the antioxidant, 2, 6-di-t-butyl-p-cresol (BHT) was used.
The obtained resin composition was extruded by an extruder to obtain a single-layer interlayer film for laminated glass having a width of 100cm, and the interlayer film was wound into a roll.
In this case, as a barrel head of an extruder used in the lip method, a barrel head having a straightness of 4 μm between 1000mm in the width direction and an unevenness of 2 μm within a range of 80mm in the width direction was used. As the press roll, a press roll having a cylindricity of 3 μm was used.
The interlayer film for laminated glass was drawn from the obtained roll, and cut at a position of 70cm in the flow direction to obtain a test sample of 70cm × film width (1 m). The test sample was placed on a flat surface at 20 ℃ and 30 RH% or less, and cured for 24 hours before measurement. After curing, the thickness was measured continuously at a rate of 1.5m/min from one end to the other end in the width direction of the test specimen using a micrometer (model KG601B wide range electronic micrometer manufactured by anli electric corporation), and the thickness was recorded at a pitch of 0.4 mm. The thickness was measured under the conditions of 20 ℃ and 30 RH% or less. Next, based on the obtained data of the thickness in the width direction, the maximum curvature of the thickness in the width direction of the interlayer film for laminated glass is calculated. First, based on the obtained data of the thickness in the width direction, the data measured while moving 0.4mm from the end of the measurement point (raw data generated every 0.4 mm) was subjected to the simple moving averaging processing in the 40mm section. After the moving averaging process, 3-degree polynomial approximations using the least square method in each 30mm interval were created while shifting the initial values by 0.4mm each time. Using a polynomial approximated function f (x), the curvature of the center within the interval is calculated. The curvature is calculated by the above formula (1). Then, the maximum value of the curvature calculated in each section was obtained and used as the maximum curvature of the thickness of the test sample in the width direction.
On the other hand, the maximum value of the thickness difference in the width direction of the interlayer film for laminated glass is calculated based on the obtained data of the thickness in the width direction. That is, based on the obtained data of the thickness in the width direction, the maximum drop height (difference between the point of maximum thickness and the point of minimum thickness) in each 150mm interval was obtained while moving 0.4mm from the end of the measurement point. The maximum difference in height in each 150mm section in the width direction was calculated, and the maximum value among these was taken as the maximum value of the thickness difference in the test sample.
(2) Manufacture of laminated glass
The interlayer film for laminated glass was drawn from the obtained roll, and cut at a position of 70cm in the flow direction to obtain an interlayer film for laminated glass having a film width of 70cm × 1 m. The interlayer film for laminated glass was placed on a flat surface at 20 ℃ and 30 RH% or less, and cured for 24 hours and then supplied to laminated glass.
The interlayer film for laminated glass was laminated between 2 glass plates having a thickness of 1.7mm, a width of 750mm and a length of 500mm, so that the width of the interlayer film for laminated glass was parallel to the length of the glass plates, the flow direction of the interlayer film for laminated glass was parallel to the length of the glass plates, and the center of the glass plates was located at the center of the interlayer film for laminated glass. Then, the exposed laminated glass was cut with an interlayer film to obtain a laminate.
The laminate thus obtained was passed through a heating zone while being conveyed by a conveyor, and after heating, air remaining between the glass and the interlayer was scraped off and removed by nip rolls, and at the same time, thermocompression bonding was performed, whereby air between the interlayer for laminated glass and the glass of the laminate was reduced and pre-pressure bonding was performed. The pre-pressed laminate was subjected to main bonding in an autoclave at high temperature and high pressure to obtain a laminated glass.
Here, the heating temperature of the heating zone was set to 220 ℃, the surface temperature of the glass after passing through the heating zone was set to 80 ℃, the temperature rise time was set to 1 minute or less, and the nip pressure was set to 3kg/cm2Hereinafter, the temperature in the autoclave was 140 ℃ at maximum, and the maximum pressure was 14kg/cm2. The heating and pressurizing time in the autoclave was set to 30 minutes at maximum.
The maximum curvature of the thickness in the width direction of the laminated glass and the maximum curvature of the thickness in the width direction of the interlayer film for laminated glass in the laminated glass were calculated for the obtained laminated glass by the same method as the evaluation of the shape of the interlayer film for laminated glass.
Comparative example 1
An interlayer film for a laminated glass was obtained in the same manner as in example 1 except that a pipe head having a straightness of 7 μm between 1000mm in the width direction and an unevenness of 2 μm in a section of 80mm in the width direction was used as a pipe head of an extruder used for the lip method, and a press roll having a cylindricity of 5 μm was used as a press roll, and the interlayer film was wound in a roll shape. Further, a laminated glass was produced in the same manner as in example 1.
Comparative example 2
An interlayer film for a laminated glass was obtained in the same manner as in example 1 except that a pipe head having a straightness of 8 μm between 1000mm in the width direction and an unevenness of 2 μm in a section of 80mm in the width direction was used as a pipe head of an extruder used for the lip method, and a press roll having a cylindricity of 6 μm was used as a press roll, and the interlayer film was wound in a roll shape. Further, a laminated glass was produced in the same manner as in example 1, and the maximum curvature of the thickness in the width direction of the laminated glass was calculated.
(example 2)
(1) Preparation of resin composition for protective layer
38.8 parts by weight of a plasticizer, 0.5 part by weight of an ultraviolet-screening agent, and 0.5 part by weight of an antioxidant were added to 100 parts by weight of a polyvinyl butyral resin, and the mixture was sufficiently kneaded by a mixing roll to obtain a protective layer resin composition. In the polyvinyl butyral, the content of hydroxyl groups was 30 mol%, the degree of acetylation was 1 mol%, the degree of butyralization was 69 mol%, and the average degree of polymerization was 1700. As the ultraviolet shielding agent, "Tinuvin 326" manufactured by BASF corporation was used. Triethylene glycol di-2-ethylhexanoate (3GO) was used as a plasticizer. As the ultraviolet-screening agent, 2- (2 '-hydroxy-3' -tert-butyl-5-methylphenyl) -5-chlorobenzotriazole (manufactured by BASF corporation, "Tinuvin 326") was used. As the antioxidant, 2, 6-di-t-butyl-p-cresol (BHT) was used.
(2) Preparation of resin composition for soundproof layer
68.8 parts by weight of a plasticizer was added to 100 parts by weight of the polyvinyl butyral resin, and the mixture was sufficiently kneaded by a mixing roll to obtain a resin composition for a sound-insulating layer. In addition, the polyvinyl butyral had a hydroxyl group content of 23.3 mol%, a degree of acetylation of 12.5 mol%, a degree of butyralization of 64.2 mol%, and an average degree of polymerization of 2300. Triethylene glycol di-2-ethylhexanoate (3GO) was used as a plasticizer.
(3) Production of interlayer film for laminated glass
An interlayer film for a laminated glass having a three-layer structure in which a cover layer (average thickness 350 μm), a sound-insulating layer (average thickness 100 μm), and a cover layer (average thickness 350 μm) were laminated in this order in the thickness direction and having a width of 100cm was obtained by co-extruding a resin composition for a sound-insulating layer and a resin composition for a cover layer, and was wound in a roll shape. In this case, a tip having a straightness of 4 μm between 1000mm in the width direction and an unevenness of 2 μm in a section of 80mm in the width direction was used as a tip of an extruder used in the lip method, and a roll having a cylindricity of 4 μm was used as a roll.
The average thickness in the width direction, the maximum curvature of the thickness in the width direction, and the maximum value of the thickness difference in the width direction of the interlayer film for laminated glass were calculated for the obtained interlayer film for laminated glass by the same method as in example 1. A laminated glass was produced in the same manner as in example 1, and the maximum curvature of the thickness in the width direction of the laminated glass and the maximum curvature of the thickness in the width direction of the interlayer film for a laminated glass in the laminated glass were calculated.
(example 3)
In the interlayer film for laminated glass obtained after the unevenness was applied, the extrusion conditions were set so that the cross-sectional shape in the thickness direction of each protective layer was a rectangle having a maximum thickness of 409 μm and a minimum thickness of 329 μm, the cross-sectional shape in the thickness direction of the soundproof layer was a rectangle having a maximum thickness of 129 μm and a minimum thickness of 98 μm, and the cross-sectional shape in the thickness direction of the entire interlayer film was a rectangle having an average film thickness of 825 μm. Except for this, an interlayer film for a laminated glass was produced in the same manner as in example 2, and the average thickness in the width direction, the maximum curvature of the thickness in the width direction, and the maximum value of the thickness difference in the width direction were calculated. A laminated glass was produced in the same manner as in example 1, and the maximum curvature of the thickness in the width direction of the laminated glass and the maximum curvature of the thickness in the width direction of the interlayer film for a laminated glass in the laminated glass were calculated.
(example 4)
(production of intermediate film for wedge-shaped laminated glass)
The resin composition for a sound-insulating layer and the resin composition for a cover layer obtained in the same manner as in example 2 were coextruded using a co-extruder, to obtain an interlayer film for a laminated glass having a 3-layer structure of a cover layer, a sound-insulating layer, and a cover layer laminated in this order in the thickness direction, and the interlayer film was wound into a roll.
In the interlayer film for laminated glass obtained after the unevenness was applied, the extrusion conditions were set so that the cross-sectional shape in the thickness direction of each protective layer was a wedge shape having a maximum thickness of 790 μm and a minimum thickness of 280 μm, the cross-sectional shape in the thickness direction of the sound-insulating layer was a wedge shape having a maximum thickness of 180 μm and a minimum thickness of 90 μm, and the cross-sectional shape in the thickness direction of the entire interlayer film was a wedge shape having a maximum thickness of 1440 μm and a minimum thickness of 700 μm. The extrusion conditions were set so that the width of the entire intermediate film was 100 cm.
In this case, the temperature of the die is adjusted by providing a temperature gradient so that the thin end portion of the entire interlayer film in the width direction is on the low temperature side and the thick end portion of the entire interlayer film is on the high temperature side in the range of the temperature of the lip die from 100 to 280 ℃. In addition, as a lip die, the gap of the lip is adjusted within the range of 1.0 to 4.0 mm. The speed difference of each roller through which the resin film discharged from the lip die passes before winding is adjusted to 15% or less. Further, the roller through which the resin film discharged from the lip die first passed was set to be lower than the die and to be located before the die in the flow direction, the extrusion amount from the extruder was adjusted to 700 kg/hour, and the speed of the roller through which the resin film first passed was adjusted to 7 m/min.
In this case, a tip having a straightness of 4 μm between 1000mm in the width direction and an irregularity of 2 μm in a section of 80mm in the width direction was used as a tip of an extruder used in the lip method, and a roll having a cylindricity of 3 μm was used as a roll.
The average thickness in the width direction, the maximum curvature of the thickness in the width direction, and the maximum value of the thickness difference in the width direction of the interlayer film for laminated glass were calculated for the obtained interlayer film for laminated glass by the same method as in example 1. A laminated glass was produced in the same manner as in example 1, and the maximum curvature of the thickness in the width direction of the laminated glass and the maximum curvature of the thickness in the width direction of the interlayer film for a laminated glass in the laminated glass were calculated.
(example 5)
(1) Preparation of resin composition for color layer
38.8 parts by weight of a plasticizer, 0.5 part by weight of an ultraviolet-screening agent, and 0.5 part by weight of an antioxidant were added to 100 parts by weight of a polyvinyl butyral resin, and the mixture was sufficiently kneaded by a mixing roll to obtain a resin composition. In the polyvinyl butyral, the content of hydroxyl groups was 30 mol%, the degree of acetylation was 1 mol%, the degree of butyralization was 69 mol%, and the average degree of polymerization was 1700. Triethylene glycol di-2-ethylhexanoate (3GO) was used as a plasticizer. As the ultraviolet-screening agent, 2- (2 '-hydroxy-3' -tert-butyl-5-methylphenyl) -5-chlorobenzotriazole (manufactured by BASF corporation, "Tinuvin 326") was used. As the antioxidant, 2, 6-di-t-butyl-p-cresol (BHT) was used.
Carbon black was added to the obtained composition as a colorant, and the resulting mixture was sufficiently kneaded with a mixing roll to obtain a resin composition for a color layer. The amount of the colorant added was set to 0.260 mass% in 100 mass% of the colored grease layer.
(2) Production of interlayer film for laminated glass
The obtained resin composition for a color layer, the resin composition for a sound-insulating layer obtained by the same method as in example 2, and the resin composition for a cover layer were coextruded using a co-extruder, whereby an interlayer film for a laminated glass having a 5-layer structure of a cover layer, a color layer, a cover layer, a sound-insulating layer, and a cover layer, which were sequentially laminated in the thickness direction, was obtained, and was wound in a roll shape.
In the interlayer film for laminated glass obtained after the unevenness was applied, the extrusion conditions were set so that the cross-sectional shapes in the thickness direction of the protective layers and the color layers were rectangles having a maximum thickness of 423 μm and a minimum thickness of 322 μm, the cross-sectional shape in the thickness direction of the noise insulation layer was rectangles having a maximum thickness of 123 μm and a minimum thickness of 96 μm, and the cross-sectional shape in the thickness direction of the entire interlayer film was a rectangle having an average thickness of 810 μm.
In this case, the temperature of the die is adjusted by providing a temperature gradient so that the thin end portion of the entire interlayer film in the width direction is on the low temperature side and the thick end portion of the entire interlayer film is on the high temperature side in the range of the temperature of the lip die from 100 ℃ to 280 ℃. In addition, as a lip die, the gap of the lip is adjusted within the range of 1.0 to 4.0 mm. The speed difference of each roller through which the resin film discharged from the lip die passes before winding is adjusted to 15% or less. Further, the roller through which the resin film discharged from the lip die first passed was set to be lower than the die and to be located before the die in the flow direction, the extrusion amount from the extruder was adjusted to 700 kg/hour, and the speed of the roller through which the resin film first passed was adjusted to 7 m/min.
In this case, a tip having a straightness of 4 μm between 1000mm in the width direction and an irregularity of 2 μm in a section of 80mm in the width direction was used as a tip of an extruder used in the lip method, and a roll having a cylindricity of 3 μm was used as a roll.
The average thickness in the width direction, the maximum curvature of the thickness in the width direction, and the maximum value of the thickness difference in the width direction of the interlayer film for laminated glass were calculated for the obtained interlayer film for laminated glass by the same method as in example 1. A laminated glass was produced in the same manner as in example 1, and the maximum curvature of the thickness in the width direction of the laminated glass and the maximum curvature of the thickness in the width direction of the interlayer film in the laminated glass were calculated.
Comparative example 3
An interlayer film for a laminated glass was obtained in the same manner as in example 2 except that a tip having a straightness of 10 μm between 1000mm in the width direction and an unevenness of 2 μm in a section of 80mm in the width direction was used as a tip of an extruder used for the lip method, and a roll having a cylindricity of 6 μm was used as a roll, and the interlayer film was wound in a roll shape. Further, a laminated glass was produced in the same manner as in example 2.
Comparative example 4
An interlayer film for a laminated glass was obtained in the same manner as in example 2 except that a pipe head having a straightness of 11 μm between 1000mm in the width direction and an unevenness of 2 μm in a section of 80mm in the width direction was used as a pipe head of an extruder used in the lip method, and a press roll having a cylindricity of 8 μm was used as a press roll, and the interlayer film was wound in a roll shape. Further, a laminated glass was produced in the same manner as in example 2.
(evaluation)
The interlayer films for laminated glasses obtained in examples and comparative examples were evaluated by the following methods. The results are shown in Table 1.
(1) Production of sample laminated glass
The interlayer film for laminated glass was drawn from the obtained roll, and cut at a position of 70cm in the flow direction to obtain an interlayer film for laminated glass having a film width of 70cm × 1 m. The interlayer film for laminated glass was placed on a flat surface at 20 ℃ and 30 RH% or less, and cured for 24 hours and then supplied to laminated glass.
The interlayer film for laminated glass was laminated between 2 glass plates having a thickness of 2mm, a width of 750mm and a length of 500mm, so that the width direction of the interlayer film for laminated glass was parallel to the length direction of the glass plates, the flow direction of the interlayer film for laminated glass was parallel to the length direction of the glass plates, and the center of the glass plates was located at the center of the interlayer film for laminated glass. Then, the exposed laminated glass was cut with an interlayer film to obtain a laminate.
The laminate thus obtained was passed through a heating zone while being conveyed by a conveyor, and after heating, air remaining between the glass and the interlayer was scraped off and removed by nip rolls, and at the same time, thermocompression bonding was performed, whereby air between the interlayer for laminated glass and the glass of the laminate was reduced and pre-pressure bonding was performed. The pre-pressed laminate was subjected to main bonding in an autoclave at high temperature and high pressure to obtain a laminated glass.
Here, the heating temperature in the heating zone was set at 220 ℃, the surface temperature of the glass after passing through the heating zone was set at 80 ℃, the temperature rise time was set at 1 minute, and the nip pressure was set at 3kg/cm2The temperature in the autoclave was 140 ℃ at maximum, and the pressure was 14kg/cm2. The heating and pressurizing time in the autoclave was set to 30 minutes at maximum.
(2) Deformation test
The obtained sample laminated glass was used for a deformation test.
Fig. 2 shows a schematic diagram illustrating the deformation test. That is, in the darkroom, the Light source 5 (S-Light SA160 manufactured by japan technology center), the laminated glass 6, and the screen 7 are arranged in a straight line so that the horizontal intervals are 3000mm and 1500mm, respectively. Here, the height of the light source 5 is set to 600mm, and the angle of the light is set to 20 ° upward from the horizontal. The height of the laminated glass 6 was 900mm at the lowest position, the angle was 18 ° so that the screen side became higher, and the laminated glass interlayer was provided so that the width direction of the interlayer was inclined from the light source to the screen. In addition, the angle of the screen 7 is set to be vertical. Note that, as the screen, a screen which is white and does not generate a shadow due to its own surface unevenness is used.
The transmission projection image projected on the screen 7 in this state is imaged by a camera 8 (FINEPIX F900EXR, manufactured by FUJIFILM corporation). The measurement conditions were: aperture f/5.9, exposure time 1/8s, ISO800, focal length 42mm, no flash, image size 4608 × 3456 pixels. The captured image is reduced to 640 × 640 pixels and subjected to 8-bit gradation processing.
Thereafter, a text file of a grayscale image was output, and 35 sections were successively selected at intervals of 10 pixels in the vertical direction of the projected image. For each section, a simple moving average (25 pixels) is taken in the vertical direction and subtracted from the section as the base luminance, thereby performing the tilt correction. Further, in order to smooth the luminance value, a simple moving average (5 pixels) is performed for each section. After calculating the dispersion values among 11 pixels in the vertical direction, the maximum value of all the luminance dispersion values in 35 is calculated. The smaller the maximum value of the luminance dispersion value is, the more the deformation can be suppressed.
[ Table 1]
Industrial applicability of the invention
According to the present invention, it is possible to provide an interlayer film for laminated glass that can provide a laminated glass in which the occurrence of perspective distortion is suppressed, a laminated glass using the interlayer film for laminated glass, and a method for producing the interlayer film for laminated glass.
Description of the reference numerals
1: intermediate film for laminated glass
2: roll-shaped body
3: test sample
5: light source
6: laminated glass
7: screen