JP2018161889A - Polyvinyl acetal resin film having polyvinyl acetal resin layer and conductive structure based on metal foil, and laminate glass having the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyvinyl acetal resin film having a conductive structure, high in production efficiency when the conductive structure is added and having no haze derived from an adhesive for adhering the conductive structure.SOLUTION: There is provided a polyvinyl acetal resin film having a polyvinyl acetal resin layer and a conductive structure based on a metal foil, which is arranged on surface or inside of the polyvinyl acetal resin layer, in which the amount of a plasticizer in the polyvinyl acetal resin layer is 0 to 20 mass% based on total amount of a resin composition constituting the polyvinyl acetal resin layer, and the polyvinyl acetal resin film has no additive agent layer between the polyvinyl acetal resin layer and the conductive structure.SELECTED DRAWING: None

Description

  The present invention relates to a polyvinyl acetal resin film having a polyvinyl acetal resin layer and a conductive structure based on a metal foil. The present invention also relates to a laminated glass having the polyvinyl acetal resin film between a plurality of transparent substrates.

  As a method of removing icing and fogging of glass in a building or vehicle, a method of applying hot air to the glass is known. However, this method has a problem that it takes time to obtain sufficient forward visibility. Further, in order to prevent malfunction of a camera or sensor attached to a glass such as a windshield, it is necessary to heat around the camera or sensor to remove icing or fogging. However, in an electric vehicle in which the heat of combustion of fuel cannot be used for this removal, there is a problem that the method of heating air with electricity and applying hot air to glass is inefficient and directly leads to a decrease in cruising distance.

Therefore, a method for removing icing and fogging by installing a heating wire on the glass and energizing it has been proposed.
For example, in Patent Document 1, an upper adhesive layer and a lower adhesive layer are placed on the upper and lower sides of the functional layer, and an upper glass plate and a lower glass plate are placed on the upper and lower sides of these upper and lower adhesive layers, and the lower adhesive layer is attached. A laminated glass with heating wire is described in which a heating wire is interposed between a layer and the lower glass plate, and specifically, an example in which a tungsten wire is used as the heating wire is described.
Further, for example, in Patent Document 2, a transparent base material, an adhesive layer provided on at least one surface of the transparent base material, a conductive heating wire provided on the adhesive layer, the conductive heating wire, and the above-mentioned A heating element is described that includes a coating film that encapsulates an upper surface of an adhesive layer that is not covered by a heating wire, a bus bar that is electrically connected to the conductive heating wire, and a power source connected to the bus bar. Specifically, an example in which a PET (polyethylene terephthalate) film is used as a transparent substrate is described.
Further, for example, in Patent Document 3, a laminated glass laminate having a conductive structure is manufactured by bonding two transparent plates, at least one sheet A and at least one sheet B. In which sheet A contains polyvinyl acetal PA and plasticizer WA, and sheet B contains polyvinyl acetal PB and plasticizer WB, and has a conductive structure on the polyvinyl acetal sheet. As a method for forming a body, general methods such as a printing method (screen printing, flexographic printing, gravure printing), vapor deposition, sputtering, and electric vapor deposition are listed. This document does not describe specific examples.

JP 2013-056811 A Special table 2013-516043 gazette US 2016/28859 A1

However, the process of arranging a large number of tungsten wires between glass plates and integrating them with a functional layer as described in Patent Document 1 is complicated and inferior in productivity. Furthermore, since a thick tungsten wire is used, a problem remains in forward visibility.
In the bonding glass using the PET film as described in Patent Document 2, two intermediate films are required, and therefore the heating element is located near the center of the bonding glass, and the heating efficiency of the glass , The PET film is inferior in curved surface followability and cannot be applied to a high curvature windshield, the PET film is inferior in elasticity, and the head impact index at the time of collision is increased, the copper foil There exists a problem that the high haze originating in the adhesive agent for adhere | attaching on a PET film will arise.
Moreover, in the method of forming a conductive structure on a polyvinyl acetal sheet as described in Patent Document 3 by a printing method, it is difficult to form a thin uniform metal wire excellent in forward visibility. . Furthermore, in the method of forming a conductive structure on a polyvinyl acetal sheet by vapor deposition or sputtering, it takes energy and time to form a thick metal layer for obtaining a necessary calorific value, resulting in a decrease in production efficiency. If the metal line width in the metal layer is increased in order to secure the necessary heat generation amount with the thin metal layer, there is a problem in that the forward visibility is lowered.

  The problem to be solved by the present invention is a polyvinyl having a conductive structure, which has high production efficiency when imparting a conductive structure and does not cause haze derived from an adhesive for bonding the conductive structure. It is to provide an acetal resin film. Moreover, another subject of this invention is providing the laminated body containing the manufacturing method of the said film, and the said film. Furthermore, another object of the present invention is to provide a laminated glass having a conductive structure that is optically excellent and can be used for a glass in a building or vehicle made of the above laminate, for example, an automobile windshield.

  In order to solve the above-mentioned problems, the present inventors have studied in detail the polyvinyl acetal resin film having a conductive structure, and have completed the present invention.

That is, the present invention includes the following preferred embodiments.
[1] A polyvinyl acetal resin film having a polyvinyl acetal resin layer and a conductive structure based on a metal foil disposed on or inside the polyvinyl acetal resin layer, the plasticizer in the polyvinyl acetal resin layer The amount is 0 to 20% by mass based on the total mass of the resin composition constituting the polyvinyl acetal resin layer, and the polyvinyl acetal resin film has an adhesive layer between the polyvinyl acetal resin layer and the conductive structure. No polyvinyl acetal resin film.
[2] Toluene / ethanol having a concentration of 10% by mass, measured at 30 ° C. and 20 ° C. using a Brookfield type (B type) viscometer of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin layer = 1/1 (mass ratio) The polyvinyl acetal resin film according to [1] above, wherein the solution has a viscosity of 200 mPa · s or more.
[3] The polyvinyl acetal resin film according to [1] or [2], wherein the polyvinyl acetal resin film has a thickness of 10 to 350 μm.
[4] The polyvinyl acetal resin film according to any one of [1] to [3], wherein the conductive structure has a thickness of 1 to 30 μm.
[5] The polyvinyl acetal resin film according to any one of [1] to [4], wherein the conductive structure is made of copper or silver.
[6] The polyvinyl acetal resin film according to any one of [1] to [5], wherein the conductive structure has a linear shape, a lattice shape, or a net shape.
[7] The polyvinyl acetal resin film according to [6], wherein the line width of the conductive structure constituting the above-described linear, lattice, or net-like shape is 1 to 30 μm.
[8] The polyvinyl acetal resin film according to any one of [1] to [7], wherein one or both surfaces of the conductive structure are subjected to a low reflectance treatment.
[9] The polyvinyl acetal resin film according to [8], wherein the low reflectance treatment is a blackening treatment.
[10] The above [1] to [9], comprising a step of bonding a metal foil and a polyvinyl acetal resin layer, and a step of forming a conductive structure from the polyvinyl acetal resin layer with metal foil obtained in the step. The manufacturing method of the polyvinyl acetal resin film in any one of.
[11] A laminate having the polyvinyl acetal resin film according to any one of [1] to [9] between a plurality of transparent substrates.
[12] A laminate having the polyvinyl acetal resin film according to any one of [1] to [9] and a plasticized polyvinyl acetal resin layer between a plurality of transparent substrates.
[13] The laminate according to [11] or [12], wherein the transparent substrate is glass.
[14] The difference between the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin film and the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the plasticized polyvinyl acetal resin layer is 4 The laminate according to [12], which is not more than mass%.
[15] A vehicle glass comprising the laminate according to any one of [11] to [14].

  According to the present invention, it is possible to obtain a polyvinyl acetal resin film having a conductive structure that has high production efficiency when imparting a conductive structure and does not cause haze derived from an adhesive for bonding the conductive structure. Can do. Moreover, the manufacturing method of the said film is provided and the laminated glass containing the said film, and obtaining the laminated glass which has the conductive structure which was optically excellent which can be used for the glass in the building or vehicle which consists of the said laminated body is obtained. it can.

  The polyvinyl acetal resin film of the present invention is a polyvinyl acetal resin film having a polyvinyl acetal resin layer and a conductive structure based on metal foil disposed on or inside the polyvinyl acetal resin layer. The amount of the plasticizer in the layer is 0 to 20% by mass based on the total mass of the resin composition constituting the polyvinyl acetal resin layer, and the polyvinyl acetal resin film is between the polyvinyl acetal resin layer and the conductive structure. It is a polyvinyl acetal resin film which does not have an adhesive bond layer.

  The thickness of the polyvinyl acetal resin film of the present invention is preferably 10 μm or more, more preferably 20 μm or more, and further preferably 30 μm or more. When the thickness of the polyvinyl acetal resin film is equal to or more than the above value, the problem that the conductive structure is distorted due to shrinkage or deformation of the polyvinyl acetal resin film hardly occurs. The thickness of the polyvinyl acetal resin film of the present invention is preferably 350 μm or less, more preferably 330 μm or less, more preferably 295 μm or less, more preferably 270 μm or less, still more preferably 250 μm or less, particularly preferably 150 μm or less, most preferably Preferably it is less than 100 μm. If the thickness of the polyvinyl acetal resin film is not more than the above value, the amount of plasticizer transferred from the laminated plastic acetal resin layer to the polyvinyl acetal resin film is reduced, and the amount of plasticizer in the plasticized polyvinyl acetal resin layer Therefore, problems such as increased head impact at the time of collision of a vehicle equipped with a vehicle glass using a polyvinyl acetal resin film are unlikely to occur. The thickness of the polyvinyl acetal resin film is measured using a thickness meter or a laser microscope.

<Resin used for constituting the polyvinyl acetal resin layer>
The polyvinyl acetal resin film of the present invention has a polyvinyl acetal resin layer.
The polyvinyl acetal resin layer includes a polyvinyl acetal resin produced by acetalization of a polyvinyl alcohol-based resin such as polyvinyl alcohol or ethylene vinyl alcohol copolymer.

  The polyvinyl acetal resin layer contains one polyvinyl acetal resin, or the viscosity average polymerization degree, the degree of acetalization, the amount of acetyl groups, the amount of hydroxyl groups, the ethylene content, the molecular weight of the aldehyde used for acetalization, and the chain length Any one or more may contain two or more different polyvinyl acetal resins. When the polyvinyl acetal resin layer contains two or more polyvinyl acetal resins different from each other, the viewpoint of easiness of melt molding, the deformation of the conductive structure when the laminated glass is produced, and the displacement of the glass when the laminated glass is used are prevented. From the viewpoint, the polyvinyl acetal resin is preferably a mixture of at least two polyvinyl acetal resins having different viscosity average polymerization degrees, or an acetalized product of a mixture of at least two polyvinyl alcohol resins having different viscosity average polymerization degrees. .

  Although the polyvinyl acetal resin used for this invention can be manufactured, for example with the following method, it is not limited to this. First, an aqueous solution of polyvinyl alcohol or ethylene vinyl alcohol copolymer having a concentration of 3 to 30% by mass is maintained in a temperature range of 80 to 100 ° C. and then gradually cooled over 10 to 60 minutes. When the temperature is lowered to −10 to 30 ° C., an aldehyde and an acid catalyst are added, and an acetalization reaction is performed for 30 to 300 minutes while keeping the temperature constant. Next, the reaction solution is heated to a temperature of 20 to 80 ° C. over 30 to 200 minutes and held for 30 to 300 minutes. Thereafter, the reaction solution is filtered as necessary, and then neutralized by adding a neutralizing agent such as alkali, and the resin is filtered, washed with water, and dried to produce the polyvinyl acetal resin used in the present invention. .

  The acid catalyst used for the acetalization reaction is not particularly limited, and both organic acids and inorganic acids can be used. Examples of such an acid catalyst include acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, hydrochloric acid and the like. Among these, hydrochloric acid, sulfuric acid and nitric acid are preferably used from the viewpoint of acid strength and ease of removal during washing.

  From the viewpoint of easily obtaining a polyvinyl acetal resin having a suitable breaking energy, the aldehyde or keto compound used for the production of the polyvinyl acetal resin is a linear, branched or cyclic compound having 2 to 10 carbon atoms. It is preferable that it is a linear or branched compound. This results in the corresponding linear or branched acetal group. The polyvinyl acetal resin used in the present invention may be an acetalized product obtained by acetalizing polyvinyl alcohol or an ethylene vinyl alcohol copolymer with a mixture of a plurality of aldehydes or keto compounds.

  The polyvinyl acetal resin used in the present invention is preferably produced by a reaction of at least one polyvinyl alcohol and one or more aliphatic unbranched aldehydes having 2 to 10 carbon atoms. As such an aldehyde, n-butyraldehyde is preferable from the viewpoint of easily obtaining a polyvinyl acetal resin having a suitable breaking energy. The content of n-butyraldehyde in the aldehyde used for acetalization is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 95% by mass or more, particularly preferably 99% by mass or more, and 100% by mass. It may be.

  The polyvinyl alcohol-based resin used for producing the polyvinyl acetal resin may be a single or a mixture of polyvinyl alcohol-based resins having different viscosity average polymerization degree or hydrolysis degree.

The viscosity average polymerization degree of the polyvinyl alcohol-based resin used as a raw material for the polyvinyl acetal resin is preferably 100 or more, more preferably 300 or more, more preferably 400 or more, and preferably 600 or more. More preferably, it is particularly preferably 700 or more, and most preferably 750 or more. When the viscosity average polymerization degree of the polyvinyl alcohol-based resin is equal to or higher than the above lower limit, deformation and disconnection of the conductive structure is easily suppressed during the production of the laminated glass, and the phenomenon that the glass is displaced due to heat in the obtained laminated glass is prevented. Cheap. Further, the viscosity average polymerization degree of the polyvinyl alcohol resin is preferably 5000 or less, more preferably 3000 or less, further preferably 2500 or less, particularly preferably 2300 or less, and 2000 or less. Most preferably. When the viscosity average polymerization degree of the polyvinyl alcohol-based resin is not more than the above upper limit value, good film forming properties are easily obtained. The viscosity average polymerization degree of the polyvinyl alcohol resin can be measured based on, for example, JIS K 6726 “Testing method for polyvinyl alcohol”.
The numerical value of the preferable viscosity average polymerization degree of the polyvinyl acetal resin is the same as the numerical value of the viscosity average polymerization degree of the polyvinyl alcohol resin described above. When the polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, it is preferable that the viscosity average polymerization degree of at least one polyvinyl acetal resin is not less than the lower limit and not more than the upper limit.

  The amount of acetyl groups in the polyvinyl acetal resin used to constitute the polyvinyl acetal resin layer is a unit consisting of two main chain carbons in the polyvinyl alcohol resin that is a raw material for producing the polyvinyl acetal resin (for example, a vinyl alcohol unit). Vinyl acetate unit, ethylene unit, etc.) as one repeating unit, and based on the one repeating unit, the vinyl acetate unit is preferably 0.1 to 20 mol%, more preferably 0.5 to 3 mol% or 5 ~ 8 mol%. By appropriately adjusting the degree of saponification of the raw material polyvinyl alcohol resin, the amount of acetyl groups can be adjusted within the above range. The amount of acetyl groups (hereinafter referred to as the amount of vinyl acetate units) affects the polarity of the polyvinyl acetal resin, which can change the plasticizer compatibility and mechanical strength of the polyvinyl acetal resin layer. When the polyvinyl acetal resin layer contains a polyvinyl acetal resin having an acetyl group content in the above range, good adhesion with a plasticized polyvinyl acetal resin layer to be laminated in some cases, reduction of optical distortion, and the like are easily achieved. When the polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the amount of acetyl groups in at least one polyvinyl acetal resin is preferably within the above range.

  The degree of acetalization of the polyvinyl acetal resin used in the present invention is not particularly limited. The degree of acetalization is a unit consisting of two main chain carbons in a polyvinyl alcohol resin that is a raw material for producing a polyvinyl acetal resin (for example, a vinyl alcohol unit, a vinyl acetate unit, an ethylene unit, etc.). It is the amount of the above unit that forms an acetal based on the repeating unit. The degree of acetalization is preferably 40 to 86 mol%, more preferably 45 to 84 mol%, more preferably 50 to 82 mol%, and further preferably 60 to 82 mol%. Preferably, it is 68-82 mol%. The degree of acetalization of the polyvinyl acetal resin can be adjusted within the above range by appropriately adjusting the amount of aldehyde used when acetalizing the polyvinyl alcohol resin. When the degree of acetalization is within the above range, the mechanical strength of the polyvinyl acetal resin film of the present invention tends to be sufficient, and the compatibility between the polyvinyl acetal resin and the plasticizer is unlikely to decrease. When the polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the degree of acetalization of at least one polyvinyl acetal resin is preferably within the above range.

  The hydroxyl group amount of the polyvinyl acetal resin is preferably 6 to 26% by mass, more preferably 12 to 24% by mass, more preferably 15 to 22% by mass, and particularly preferably 18 to 20% by mass as the vinyl alcohol unit of the polyvinyl acetal resin. 21% by mass. When the amount of the hydroxyl group is within the above range, the difference in refractive index from the plasticized polyvinyl acetal resin layer to be laminated becomes small, and a laminated glass with little optical unevenness is easily obtained. On the other hand, a preferable range for further providing sound insulation performance is 6 to 20% by mass, more preferably 8 to 18% by mass, further preferably 10 to 15% by mass, and particularly preferably 11 to 13% by mass. . By adjusting the amount of aldehyde used when acetalizing the polyvinyl alcohol resin, the amount of hydroxyl groups (hereinafter, the amount of vinyl alcohol units) can be adjusted within the above range. When the polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the hydroxyl group amount of at least one polyvinyl acetal resin is preferably within the above range.

  The polyvinyl acetal resin is usually composed of an acetal group unit, a hydroxyl unit and an acetyl group unit. The amount of each unit is determined by, for example, JIS K 6728 “Testing method for polyvinyl butyral” or nuclear magnetic resonance (NMR). It can be measured.

  When the polyvinyl acetal resin contains a unit other than the acetal group unit, the unit amount of the hydroxyl group and the unit amount of the acetyl group are measured, and these unit amounts are not included in the unit other than the acetal group unit. The remaining acetal group unit amount can be calculated by subtracting from the unit amount.

The polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin layer was measured at 20 ° C. and 30 rpm using a Brookfield type (B type) viscometer. The viscosity of the 1 (mass ratio) solution is preferably 200 mPa · s or more, more preferably 240 mPa · s or more, and particularly preferably 265 mPa · s or more. The viscosity of the polyvinyl acetal resin can be adjusted to the lower limit value or more by using or using a polyvinyl acetal resin produced by using a polyvinyl alcohol resin having a high viscosity average polymerization degree as a raw material or a part of the raw material. When the polyvinyl acetal resin used for constituting the polyvinyl acetal resin layer is composed of a mixture of a plurality of resins, it is preferable that the viscosity of the mixture is not less than the lower limit. When the viscosity of the polyvinyl acetal resin is equal to or higher than the lower limit, deformation and disconnection of the conductive structure are easily suppressed during the production of the laminated glass, and the phenomenon that the glass is displaced due to heat in the obtained laminated glass is easily prevented.
The upper limit of the viscosity is usually 1000 mPa · s, preferably 800 mPa · s, more preferably 500 mPa · s, still more preferably 450 mPa · s, and particularly preferably 400 mPa · s, from the viewpoint that good film forming properties are easily obtained. s.

The peak top molecular weight of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin layer is preferably 115,000 to 200,000, more preferably 120,000 to 160,000, and particularly preferably 130,000 to 150,000. The peak top molecular weight of a polyvinyl acetal resin can be adjusted within the said range by using or using together the polyvinyl acetal resin manufactured using the polyvinyl alcohol-type resin with a high viscosity average polymerization degree as a raw material or a part of raw material. When the peak top molecular weight of the polyvinyl acetal resin is within the above range, suitable film-forming properties and suitable film physical properties (for example, laminate suitability, creep resistance, and breaking strength) are easily obtained.
The molecular weight distribution of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin layer, that is, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 2.7 or more. , More preferably 2.8 or more, particularly preferably 2.9 or more. By acetalizing a mixture of polyvinyl alcohol resins with different viscosity average polymerization degrees, or by mixing acetalization products of polyvinyl alcohol resins with different viscosity average polymerization degrees, the molecular weight distribution of the polyvinyl acetal resin exceeds the lower limit. Can be adjusted. When the molecular weight distribution of the polyvinyl acetal resin is equal to or more than the lower limit, it is easy to achieve both film-forming properties and suitable film properties (for example, laminate suitability, creep resistance, and breaking strength). The upper limit value of the molecular weight distribution is not particularly limited. The molecular weight distribution is usually 10 or less, preferably 5 or less, from the viewpoint of film formation.
When the polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the peak top molecular weight and molecular weight distribution of at least one polyvinyl acetal resin are preferably within the above ranges.
The peak top molecular weight and molecular weight distribution are obtained, for example, using gel permeation chromatography (GPC) and polystyrene having a known molecular weight as a standard.

  The polyvinyl acetal resin layer may have a multi-component layer separation structure, but the layer separation structure preferably has an average particle size of the island component of less than 100 nm, more preferably less than 80 nm, It is particularly preferable that the layer separation structure is not exhibited. By showing the sea-island layer separation structure or showing a sufficiently small particle size, it is possible to ensure transparency that can be used for a windshield of a car.

  The polyvinyl acetal resin layer preferably contains uncrosslinked polyvinyl acetal from the viewpoint of easily obtaining good film-forming properties. It is also possible for the polyvinyl acetal resin layer to contain a crosslinked polyvinyl acetal. Methods for crosslinking polyvinyl acetals are, for example, EP 1527107B1 and WO 2004/062311 A1 (thermal self-crosslinking of carboxyl group-containing polyvinyl acetals), EP 1606325 A1 (polyvinyl acetals crosslinked with polyaldehydes), and WO 2003 / 020776 A1 (polyvinyl acetal crosslinked with glyoxylic acid). It is also a useful method to control the amount of intermolecular acetal bonds produced and to control the degree of blocking of residual hydroxyl groups by appropriately adjusting the acetalization reaction conditions.

<Plasticizer>
In this invention, the quantity of the plasticizer in a polyvinyl acetal resin layer is 0-20 mass% based on the total mass of the resin composition which comprises a polyvinyl acetal resin layer. When the amount of the plasticizer exceeds 20% by mass, good film-formability cannot be obtained, and deformation and / or disconnection of the conductive structure occurs during the production of the laminated glass. As a result, good electrical conductivity can be obtained. Absent.
The amount of the plasticizer is preferably 0 to 19% by mass, more preferably 0 to 15% by mass, further preferably 0 to 10% by mass, and particularly preferably 0 to 5% by mass. When the amount of the plasticizer in the polyvinyl acetal resin layer is within the above range, a polyvinyl acetal resin film excellent in film forming property and handleability can be easily produced, and conductive when producing a laminated glass using the polyvinyl acetal resin film. Deformation and disconnection of the structure are easily suppressed, and as a result, good electrical conductivity is easily obtained.

When a plasticizer is contained in the polyvinyl acetal resin layer, one or more compounds of the following group are preferably used as the plasticizer.
-Esters of polyvalent aliphatic or aromatic acids. For example, dialkyl adipates (eg, dihexyl adipate, di-2-ethylbutyl adipate, dioctyl adipate, di-2-ethylhexyl adipate, hexyl cyclohexyl adipate, diheptyl adipate, dinonyl adipate, diisononyl adipate, heptyl nonyl adipate); adipic acid Esters of alcohols and alcohols including ethers (eg di (butoxyethyl) adipate, di (butoxyethoxyethyl) adipate); dialkyl sebacates (eg dibutyl sebacate); sebacic acid and alicyclic or ether compounds Esters with alcohols including: esters of phthalic acid (eg, butylbenzyl phthalate, bis-2-butoxyethyl phthalate); and alicyclic polyvalent cal Phosphate esters of aliphatic alcohols (e.g., 1,2-cyclohexane dicarboxylic acid diisononyl esters).
Polyhydric aliphatic or aromatic alcohols or oligoether glycol esters or ethers having one or more aliphatic or aromatic substituents. Examples thereof include esters of glycerin, diglycol, triglycol, tetraglycol and the like with a linear or branched aliphatic or alicyclic carboxylic acid. Specifically, diethylene glycol-bis- (2-ethylhexanoate), triethylene glycol-bis- (2-ethylhexanoate) (hereinafter sometimes referred to as “3GO”), triethylene glycol- Bis- (2-ethylbutanoate), tetraethylene glycol-bis-n-heptanoate, triethylene glycol-bis-n-heptanoate, triethylene glycol-bis-n-hexanoate, tetraethylene glycol dimethyl ether, and dipropylene glycol Dibenzoate is mentioned.
-Phosphate esters of aliphatic or aromatic alcohols. Examples include tris (2-ethylhexyl) phosphate (TOF), triethyl phosphate, diphenyl-2-ethylhexyl phosphate, and tricresyl phosphate.
-Esters of citric acid, succinic acid and / or fumaric acid.

  In addition, polyesters or oligoesters composed of polyhydric alcohol and polycarboxylic acid, terminal esterified products or etherified products thereof, polyesters or oligoesters composed of lactone or hydroxycarboxylic acid, or terminal esterified products or etherified products thereof. It may be used as a plasticizer.

  When a plasticizer is contained in the polyvinyl acetal resin layer, the viewpoint of suppressing problems (for example, problems such as changes in physical properties over time) associated with the plasticizer moving between the laminated plasticized polyvinyl acetal resin layers The same plasticizer as that contained in the plasticized polyvinyl acetal resin layer when laminated, or the physical properties (for example, heat resistance, light resistance, transparency, and plasticization efficiency) of the plasticized polyvinyl acetal resin layer are not impaired. It is preferred to use a plasticizer. From such a viewpoint, as the plasticizer, triethylene glycol-bis- (2-ethylhexanoate), triethylene glycol-bis (2-ethylbutanoate), tetraethylene glycol-bis- (2-ethylhexanoate) Noate) and tetraethylene glycol-bisheptanoate, and particularly preferably triethylene glycol-bis- (2-ethylhexanoate).

<Additives>
Furthermore, the polyvinyl acetal resin layer may contain another additive. Such additives include, for example, water, ultraviolet absorbers, antioxidants, adhesion modifiers, brighteners or fluorescent brighteners, stabilizers, dyes, processing aids, impact modifiers, fluidity. Examples thereof include an improving agent, a crosslinking agent, a pigment, a light emitting material, a refractive index adjusting agent, a heat shielding material, organic or inorganic nanoparticles, calcined silicic acid, and a surfactant.

  In a certain aspect, in order to suppress the corrosion of the electroconductive structure contained in a polyvinyl acetal resin film, it is preferable that a polyvinyl acetal resin film contains a corrosion inhibitor. In such a case, the corrosion inhibitor is preferably contained in the polyvinyl acetal resin layer. The amount of the corrosion inhibitor contained in the polyvinyl acetal resin layer is preferably 0.005 to 5% by mass based on the mass of the resin composition constituting the polyvinyl acetal resin layer. Examples of corrosion inhibitors include substituted or unsubstituted benzotriazole.

<Method for producing polyvinyl acetal resin layer>
The manufacturing method of a polyvinyl acetal resin layer is not specifically limited. The resin, optionally a predetermined amount of a plasticizer, and other additives as necessary are blended and kneaded uniformly, and then a known method such as an extrusion method, a calendering method, a pressing method, a casting method, an inflation method, etc. A sheet (layer) is produced by a film forming method, and this can be used as a polyvinyl acetal resin layer.

Among known film forming methods, a method of producing a sheet (layer) using an extruder is particularly preferably employed. The resin temperature during extrusion is preferably 150 to 250 ° C, and more preferably 170 to 230 ° C. When the resin temperature becomes too high, the polyvinyl acetal resin is decomposed and the content of volatile substances is increased. On the other hand, when the temperature is too low, the content of volatile substances increases. In order to efficiently remove the volatile substance, it is preferable to remove the volatile substance from the vent port of the extruder by reducing the pressure.
When manufacturing a polyvinyl acetal resin layer using an extruder, you may melt-extrude a polyvinyl acetal resin layer on metal foil so that it may mention later.
In addition, when producing a polyvinyl acetal resin layer using an extruder, there is no particular limitation on the roll to be used, but in order to form a smoother surface, it is preferable to use a combination of an elastic roll and a mirror metal roll, It is more preferable to use a metal elastic roll and a mirror metal roll in combination.

<Conductive structure>
The polyvinyl acetal resin film of this invention has the electroconductive structure based on metal foil in the surface or inside of a polyvinyl acetal resin layer.
A polyvinyl acetal resin film having a conductive structure on the surface of the polyvinyl acetal resin layer is, for example, thermocompression bonding the polyvinyl acetal resin layer and the metal foil, or melt-extrusion of the polyvinyl acetal resin layer on the metal foil, Then, it manufactures by producing a conductive structure using the technique of photolithography.
The polyvinyl acetal resin film having a conductive structure inside the polyvinyl acetal resin layer is formed on the surface having the conductive structure of the polyvinyl acetal resin layer having a conductive structure on the surface produced as described above. The polyvinyl acetal resin layer is overlaid and thermocompression-bonded, or the polyvinyl acetal resin layer is melt-extruded on the surface having the conductive structure. That is, “disposed on the surface or inside of the polyvinyl acetal resin layer” means “disposed on the surface of the polyvinyl acetal resin layer or disposed between the two polyvinyl acetal resin layers”. means. In this case, the resin composition constituting the polyvinyl acetal resin layer previously bonded to the metal foil and the resin composition constituting the polyvinyl acetal resin layer later bonded to the metal foil have the same composition. Alternatively, they may have different compositions.
The polyvinyl acetal resin film of the present invention does not have an adhesive layer between the polyvinyl acetal resin layer and the conductive structure. Therefore, the haze derived from the adhesive for adhering the conductive structure does not occur, and the laminated glass produced using the polyvinyl acetal resin film of the present invention has excellent optical properties.

  The thickness of the conductive structure is preferably from 1 to 30 μm, more preferably from 2 to 20 μm, even more preferably from 3 to 15 μm, and particularly preferably from 3 to 30 μm, from the viewpoint of easily reducing light reflection and obtaining a necessary calorific value. 12 μm. The thickness of the conductive structure is measured using a thickness meter or a laser microscope.

  The conductive structure is preferably made of copper or silver from the viewpoint of easy etching and easy availability of the metal foil. That is, the metal foil is preferably a copper foil or a silver foil.

  The conductive structure preferably has a linear shape, a lattice shape, or a net shape from the viewpoint of facilitating forward visibility and necessary heat generation. Here, examples of the line shape include a straight line shape, a wavy line shape, and a zigzag shape. In one conductive structure, the shape may be single or a plurality of shapes may be mixed.

  The line width of the conductive structure constituting a linear, lattice-like or net-like shape is preferably 1 to 30 μm, more preferably 2 to 15 μm, and particularly preferably 3 to 12 μm. When the line width of the conductive structure is within the above range, a sufficient amount of heat generation is easily secured, and desired forward visibility is easily obtained.

One side or both sides of the conductive structure is preferably subjected to low reflectance treatment.
In the present invention, “being processed with low reflectance” means that the visible light reflectance measured in accordance with JIS R 3106 is 30% or less. From the viewpoint of better front visibility, it is more preferable that the visible light reflectance is 10% or less. When the visible light reflectance is less than or equal to the above upper limit, a desired visible light reflectance is obtained when a vehicle glass is produced by laminating a polyvinyl acetal resin film and a plasticized polyvinyl acetal resin layer as described later. It is easy to be done.

Examples of the low reflectance treatment method include blackening treatment (darkening treatment), browning treatment, and plating treatment. From the viewpoint of process passability, the low reflectance treatment is preferably a blackening treatment. Therefore, from the viewpoint of good forward visibility, it is particularly preferable that one side or both sides of the conductive structure is blackened so that the visible light reflectance is 10% or less.
Specifically, the blackening treatment is performed using an alkaline blackening solution or the like.

<Method for producing polyvinyl acetal resin film>
The polyvinyl acetal resin film of the present invention includes, for example, a step of bonding a metal foil and a polyvinyl acetal resin layer, and a step of forming a conductive structure from the polyvinyl acetal resin layer with metal foil obtained in the above step. Manufactured by.

The step of joining the metal foil and the polyvinyl acetal resin layer is performed by, for example, the following methods (I) to (III).
(I) A method in which a polyvinyl acetal resin layer and a metal foil are stacked and thermocompression bonded,
(II) A method of coating and joining a melt of a resin composition constituting a polyvinyl acetal resin layer on a metal foil, for example, a method of melt-extruding the resin composition on a metal foil, or the above on a metal foil A method of applying the resin composition by knife coating or the like, or (III) a solvent or a resin composition solution or dispersion containing the resin and solvent contained in the polyvinyl acetal resin layer, one of the metal foil and the polyvinyl acetal resin layer Or the method of apply | coating to both or inject | pouring between metal foil and a polyvinyl acetal resin layer, and joining a metal foil and a polyvinyl acetal resin layer.

The bonding temperature at the time of thermocompression bonding in the above method (I) depends on the type of resin contained in the polyvinyl acetal resin layer, but is usually 70 to 170 ° C, preferably 90 to 160 ° C, more preferably 100 to 155 ° C. More preferably, it is 110-150 degreeC. When the bonding temperature is within the above range, good bonding strength is easily obtained.
The resin temperature at the time of extrusion in the above method (II) is preferably 150 to 250 ° C, more preferably 170 to 230 ° C, from the viewpoint of reducing the content of volatile substances in the polyvinyl acetal resin layer. In order to remove the substance efficiently, it is preferable to remove the volatile substance from the vent port of the extruder by decompression.
As the solvent in the above method (III), it is preferable to use a plasticizer usually used for polyvinyl acetal resins. As such a plasticizer, those described in the paragraph of <Plasticizer> above are used.

  The process of forming a conductive structure from the obtained polyvinyl acetal resin layer with metal foil is carried out using a known photolithography technique. In the process, for example, as described in the following examples, after laminating a dry film resist on the metal foil of the polyvinyl acetal resin layer with metal foil, an etching resistance pattern is formed using a photolithography technique, and then, After the polyvinyl acetal resin layer provided with the etching resistance pattern is immersed in a copper etching solution to form a conductive structure, the remaining photoresist layer is removed by a known method.

  Since the method for producing a polyvinyl acetal resin film in the present invention can easily and easily form a conductive structure of a desired shape, the production efficiency when imparting the conductive structure to the polyvinyl acetal resin layer is remarkably high. Improved.

<Laminate>
The present invention also relates to a laminate having the polyvinyl acetal resin film between a plurality of transparent substrates.

  The present invention also relates to a laminate having the polyvinyl acetal resin film and a plasticized polyvinyl acetal resin layer between a plurality of transparent substrates.

  Each wiring of the conductive structure in the laminate is connected to a bus bar. As the bus bar, a bus bar usually used in the art is used, and examples thereof include a metal foil tape, a metal foil tape with a conductive adhesive, and a conductive paste. Moreover, you may form a bus-bar by leaving a part of metal foil as a bus-bar simultaneously with the formation of the electroconductive structure in this invention. A power supply line is connected to each bus bar, and each power supply line is connected to a power source, so that a current is supplied to the conductive structure.

  From the viewpoint of transparency, weather resistance and mechanical strength, the transparent substrate is preferably inorganic glass (hereinafter sometimes simply referred to as glass), or a methacrylic resin sheet, a polycarbonate resin sheet, a polystyrene resin sheet, or a polyester resin. An organic glass such as a resin sheet or a polycycloolefin-based resin sheet, more preferably an inorganic glass, a methacrylic resin sheet, or a polycarbonate resin sheet, and particularly preferably an inorganic glass. The inorganic glass is not particularly limited, and examples thereof include float glass, tempered glass, semi-tempered glass, chemically tempered glass, green glass, and quartz glass.

In the laminate, the conductive structure in the polyvinyl acetal resin film may be in contact with the transparent substrate, may be in contact with the plasticized polyvinyl acetal resin layer, or another functional layer to be described later. May be in contact with.
When the transparent substrate is glass, if the conductive structure in the polyvinyl acetal resin film is in direct contact with the glass, the bus bar and / or the conductive structure is not sufficiently sealed and moisture penetrates. The conductive structure in the polyvinyl acetal resin film is made of glass because the bus bar and / or the conductive structure may be corroded, or air may remain during the production of the laminate to cause bubbles to remain or peel off. It is preferable not to touch directly.
Further, when the polyvinyl acetal resin film of the present invention is used particularly in a vehicle glass, particularly a vehicle windshield, the surface of the conductive structure subjected to low reflectance treatment is used from the viewpoint of forward visibility. It is preferable to arrange a polyvinyl acetal resin film so as to be on the side.

  Moreover, since there exists a possibility that a water | moisture content may penetrate | invade from a laminated body edge part and cause a corrosion of an electroconductive structure, it is preferable that the electroconductive structure is arrange | positioned 1 cm or more inside from the edge part of a laminated body.

The laminate in the present invention can have the following layer structure, but is not limited thereto.
(1) Three-layer configuration of transparent substrate A / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / transparent substrate B,
(2) 4 layer constitution of transparent substrate A / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / another functional layer / transparent substrate B,
(3) 4 layer constitution of transparent substrate A / another functional layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / transparent substrate B,
(4) 4 layer constitution of transparent substrate A / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / plasticized polyvinyl acetal resin layer / transparent substrate B,
(5) 4 layer constitution of transparent substrate A / plasticized polyvinyl acetal resin layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / transparent substrate B,
(6) 5 layer constitution of transparent substrate A / plasticized polyvinyl acetal resin layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / plasticized polyvinyl acetal resin layer / transparent substrate B,
(7) 5 layer constitution of transparent substrate A / another functional layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / plasticized polyvinyl acetal resin layer / transparent substrate B,
(8) 5-layer constitution of transparent substrate A / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / another functional layer / plasticized polyvinyl acetal resin layer / transparent substrate B,
(9) 5 layer constitution of transparent substrate A / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / plasticized polyvinyl acetal resin layer / another functional layer / transparent substrate B,
(10) 5-layer configuration of transparent substrate A / another functional layer / plasticized polyvinyl acetal resin layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / transparent substrate B,
(11) Five-layer configuration of transparent substrate A / plasticized polyvinyl acetal resin layer / another functional layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / transparent substrate B,
(12) Transparent base material A / plasticized polyvinyl acetal resin layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / another functional layer / transparent base material B, 5 layer structure,
(13) 6 of transparent substrate A / another functional layer / plasticized polyvinyl acetal resin layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / plasticized polyvinyl acetal resin layer / transparent substrate B Layer structure,
(14) Transparent substrate A / plasticized polyvinyl acetal resin layer / another functional layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / plasticized polyvinyl acetal resin layer / transparent substrate B 6 Layer structure,
(15) Transparent substrate A / plasticized polyvinyl acetal resin layer / polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure) / another functional layer / plasticized polyvinyl acetal resin layer / transparent substrate B 6 Layer structure,
(16) In the layer structures (1) to (15), the “polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure)” is changed to “polyvinyl acetal resin film (polyvinyl acetal resin layer / conductive structure / polyvinyl). The layer structure replaced with “acetal resin layer)”.

When it is required to mainly heat the transparent substrate outside the vehicle, for example, to melt the snow accumulated on the transparent substrate, the polyvinyl acetal resin film is in contact with the transparent substrate outside the vehicle, for example, the layer In the configuration (4), it is preferable that the transparent substrate A is an outer transparent substrate and the transparent substrate B is an inner transparent substrate.
When it is required to mainly heat the transparent substrate inside the vehicle, for example, to remove fog in the vehicle, the polyvinyl acetal resin film is in contact with the transparent substrate inside the vehicle, for example, the layer configuration ( In 4), it is preferable that the transparent substrate A has an inner transparent substrate and the transparent substrate B has an outer transparent substrate.

<Plasticized polyvinyl acetal resin layer>
The polyvinyl acetal resin film of the present invention can be used alone, but is more preferably used in combination with a plasticized polyvinyl acetal resin layer.
The plasticized polyvinyl acetal resin layer includes a polyvinyl acetal resin produced by acetalization of polyvinyl alcohol or ethylene vinyl alcohol copolymer.

  The optionally laminated plasticized polyvinyl acetal resin layer contains one polyvinyl acetal resin, or viscosity average polymerization degree, acetalization degree, acetyl group quantity, hydroxyl group quantity, ethylene content, aldehyde used for acetalization. Two or more polyvinyl acetal resins different in any one or more of molecular weight and chain length may be included.

  The polyvinyl acetal resin can be produced, for example, by a method similar to the method described in the preceding paragraph <Resin used for constituting the polyvinyl acetal resin layer>.

  The amount of acetyl groups in the polyvinyl acetal resin used to constitute the plasticized polyvinyl acetal resin layer is a unit composed of two main chain carbons in the polyvinyl alcohol resin that is a raw material for producing the polyvinyl acetal resin (for example, vinyl An alcohol unit, a vinyl acetate unit, an ethylene unit, etc.) as one repeating unit, and based on the one repeating unit, the vinyl acetate unit is preferably 0.1 to 20 mol%, more preferably 0.5 to 3 mol%. Or it is 5-8 mol%. By appropriately adjusting the degree of saponification of the raw material polyvinyl alcohol resin, the amount of acetyl groups can be adjusted within the above range. When the plasticized polyvinyl acetal resin layer contains a polyvinyl acetal resin having an acetyl group content in the above range, a plasticized polyvinyl acetal resin layer excellent in compatibility with a plasticizer is easily obtained. When the plasticized polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the amount of acetyl groups in at least one polyvinyl acetal resin is preferably within the above range.

  The degree of acetalization of the polyvinyl acetal resin is not particularly limited. The degree of acetalization is preferably 40 to 86 mol%, more preferably 45 to 84 mol%, more preferably 50 to 82 mol%, and further preferably 60 to 82 mol%. Preferably, it is 68-82 mol%. The degree of acetalization of the polyvinyl acetal resin can be adjusted within the above range by appropriately adjusting the amount of aldehyde used when acetalizing the polyvinyl alcohol resin. When the degree of acetalization is within the above range, it is easy to obtain a plasticized polyvinyl acetal resin layer having excellent penetration resistance or adhesion to glass when it is made into a laminated glass. When the plasticized polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the degree of acetalization of at least one polyvinyl acetal resin is preferably within the above range.

  The amount of hydroxyl groups in the polyvinyl acetal resin is preferably 6 to 26% by mass, more preferably 12 to 24% by mass, more preferably 15 to 22% by mass, and particularly preferably 18 to 21% by mass as the mass of vinyl alcohol units. It is. When the amount of the hydroxyl group is within the above range, a laminated glass excellent in penetration resistance, adhesiveness, or sound insulation is easily obtained. On the other hand, a preferable range for further providing sound insulation performance is 6 to 20% by mass, more preferably 8 to 18% by mass, further preferably 10 to 15% by mass, and particularly preferably 11 to 13% by mass. . By adjusting the amount of aldehyde used when acetalizing the polyvinyl alcohol-based resin, the amount of hydroxyl groups can be adjusted within the above range. When the plasticized polyvinyl acetal resin layer contains two or more different polyvinyl acetal resins, the hydroxyl group amount of at least one polyvinyl acetal resin is preferably within the above range.

  The polyvinyl acetal resin can be measured by, for example, JIS K 6728 “Testing method for polyvinyl butyral” or nuclear magnetic resonance (NMR).

The plasticized polyvinyl acetal resin layer is uncrosslinked from the viewpoint that good film-forming properties and laminate suitability are easily obtained, and the head impact at the time of collision is easily reduced in vehicle glass including the plasticized polyvinyl acetal resin layer. It is preferable that the polyvinyl acetal is included. It is also possible for the plasticized polyvinyl acetal resin layer to contain a crosslinked polyvinyl acetal. The method for cross-linking polyvinyl acetal is exemplified in the preceding paragraph <Resin used for constituting the polyvinyl acetal resin layer>.
.

The plasticized polyvinyl acetal resin layer contains a plasticizer in addition to the polyvinyl acetal resin. The content of the plasticizer is preferably 16.0% by mass or more, more preferably 16.1%, based on the total mass of the resin composition constituting the plasticized polyvinyl acetal resin layer in the initial state before the layers are laminated. It is -36.0 mass%, More preferably, it is 22.0-32.0 mass%, Most preferably, it is 26.0-30.0 mass%. When the plasticizer content is within the above range, a laminated glass excellent in impact resistance is easily obtained. Further, as the plasticized polyvinyl acetal resin layer, a plasticized polyvinyl acetal resin layer having a sound insulating function can also be used. In that case, the content of the plasticizer is preferably 30% by mass or more, more preferably 30 to 30% by mass based on the total mass of the resin composition constituting the plasticized polyvinyl acetal resin layer in the initial state before the layers are laminated. 50 mass%, More preferably, it is 31-40 mass%, Most preferably, it is 32-35 mass%.
As the plasticizer, the plasticizers described in the preceding <Plasticizer> paragraph may be used.

  The plasticized polyvinyl acetal resin layer may contain the additives described in the previous <Additive> paragraph, if necessary.

<Method for producing plasticized polyvinyl acetal resin layer>
The plasticized polyvinyl acetal resin layer may be produced by the method described in the previous paragraph <Method for producing polyvinyl acetal resin layer>.

In the laminate of the present invention, the hydroxyl amount of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin film, and the hydroxyl amount of the polyvinyl acetal resin in the resin composition constituting the plasticized polyvinyl acetal resin layer The difference is preferably 4% by mass or less, more preferably 3% by mass or less, and particularly preferably 2% by mass or less as the mass% of the vinyl alcohol unit. When the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin layer and / or the polyvinyl acetal resin in the resin composition constituting the plasticized polyvinyl acetal resin layer is composed of a mixture of a plurality of resins, the polyvinyl acetal resin layer It is preferable that the difference between the amount of hydroxyl group of at least one polyvinyl acetal resin contained and the amount of hydroxyl group of at least one polyvinyl acetal resin contained in the plasticized polyvinyl acetal resin layer is not more than the upper limit. When the difference is less than or equal to the upper limit value, the refractive index difference between the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer becomes small in an equilibrium state after the plasticizer has migrated in the laminate, so the dimensions are different from each other. When a plasticized polyvinyl acetal resin layer and a polyvinyl acetal resin film are used, the boundary is difficult to visually recognize, which is preferable.
On the other hand, by making the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin film lower than the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the plasticized polyvinyl acetal resin layer, It is also a preferred embodiment that the average amount of plasticizer in the polyvinyl acetal resin film in an equilibrium state after the plasticizer is transferred in the laminate is 30% by mass or more. In that case, the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin film is 5% by mass than the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the plasticized polyvinyl acetal resin layer. It is preferably lower, more preferably 8% by mass or higher. It is preferable that the difference in the amount of hydroxyl groups is equal to or greater than the lower limit because the amount of plasticizer in the polyvinyl acetal resin layer in an equilibrium state can be sufficiently increased, and a laminated glass having a sound insulation function can be easily obtained.

<Another functional layer>
The laminate of the present invention may have another functional layer in addition to the polyvinyl acetal resin film or in addition to the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer.
As another functional layer, for example, an infrared reflection layer, an ultraviolet reflection layer, a color correction layer, an infrared absorption layer, an ultraviolet absorption layer, a fluorescent / light emitting layer, a sound insulation layer, an electrochromic layer, a thermochromic layer, a photochromic layer, a design An elastic layer or a high elastic modulus layer.

<Method for producing laminate>
The laminate can be produced by a method known to those skilled in the art. For example, in the case of laminating a polyvinyl acetal resin film and a transparent substrate on a transparent substrate, an arbitrary number of plasticized polyvinyl acetal resin layers are arranged in an arbitrary order, and another transparent substrate is further stacked. When a polyvinyl acetal resin film and a laminate are laminated by increasing the temperature as a crimping step, a laminate can be produced by fusing the plasticized polyvinyl acetal resin layer entirely or locally to a transparent substrate and then treating with an autoclave. .

  Moreover, after laminating a polyvinyl acetal resin film and, in the case of lamination, a plasticized polyvinyl acetal resin layer and / or another functional layer in advance, they are arranged between two transparent substrates and fused together at a high temperature. Thus, a laminate may be manufactured.

  As the pre-pressing step, from the viewpoint of removing excess air or performing light joining between adjacent layers, a method of degassing under reduced pressure by a method such as a vacuum bag, a vacuum ring, or a vacuum laminator, Examples thereof include a method of deaeration using a nip roll and a method of compression molding at a high temperature.

For example, the vacuum bag method or the vacuum ring method described in EP 1235683 B1 is carried out at about 2 × 10 ⁴ Pa and 130 to 145 ° C., for example.

A vacuum laminator consists of a heatable and vacuumable chamber in which a laminate is formed within a period of about 20 minutes to about 60 minutes. Usually, a reduced pressure of 1 Pa to 3 × 10 ⁴ Pa and a temperature of 100 ° C. to 200 ° C., particularly 130 ° C. to 160 ° C. are effective. When using a vacuum laminator, the treatment in the autoclave may not be performed depending on the temperature and pressure.

Treatment in an autoclave is carried out, for example about 1 × ¹⁰ 6 at a pressure and at a temperature of about 100 ° C. ~ about 145 ° C. for Pa~ about 1.5 × ¹⁰ 6 Pa 20 minutes to 2 hours.

  In the case of the simplest layer configuration, a polyvinyl acetal resin film is placed on the first transparent substrate to produce a laminate, and when laminated, a plasticized polyvinyl acetal resin layer is placed simultaneously or subsequently. Then, a second transparent base material is disposed thereon to produce a composite material. Here, the order of the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer may be reversed. Next, this composite material is subjected to the preliminary press-bonding step. Optionally, a degassing step may be included.

  Finally, the composite material is subjected to an autoclave process as needed.

  The method of disposing the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer in the case of laminating before placing the second transparent substrate after placing the polyvinyl acetal resin film on the first transparent substrate is particularly limited. Instead, various methods are applied. For example, the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer may be arranged by supplying from a roll having an appropriate width and cutting to a desired size, or cutting to a desired size in advance. You may arrange the film. For example, when the laminate is an automobile windshield, a plasticized polyvinyl acetal resin layer supplied from a roll may be heated, stretched, cut, and processed into a fan shape.

  In the automobile field, particularly when a windshield is manufactured, the upper part of the glass may be manufactured to have a so-called color shade region. Therefore, the polyvinyl acetal resin film and / or the plasticized polyvinyl acetal resin layer in the case of lamination are extruded together with a correspondingly colored polymer melt, or the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer. At least one of them may have a partially different coloration. In the present invention, such coloring may be performed by completely or partially coloring at least one of the polyvinyl acetal resin film and the plasticized polyvinyl acetal resin layer.

  Accordingly, in the present invention, the plasticized polyvinyl acetal resin layer in the case of lamination may have a color gradation adapted to the shape of the windshield, particularly in the process steps that have already been preceded.

  The plasticized polyvinyl acetal resin layer may have a wedge-shaped thickness profile. Thereby, the laminate of the present invention can have a wedge-shaped thickness profile even when the thickness profile of the polyvinyl acetal resin film is a parallel plane, and is used for a head-up display (HUD) in an automobile windshield. it can.

  The plasticized polyvinyl acetal resin layer may be a commercially available plasticized polyvinyl butyral sheet with or without a color shade and with or without a thick wedge-shaped thickness profile. Similarly, a plasticized polyvinyl acetal resin layer having nanoparticles having infrared absorbing ability or reflectivity dispersed in a plasticized polyvinyl acetal resin layer or a colored plasticized polyvinyl acetal resin layer is used for infrared shielding. May be. Naturally, since the plasticized polyvinyl acetal resin layer may be a sheet having a sound insulation function, improved sound insulation characteristics can be obtained by combination with the polyvinyl acetal resin film. Of course, the plasticized polyvinyl acetal resin layer can also integrate in itself several of the functions described above.

  The laminated body of this invention is used as a laminated glass in a building or a vehicle. Accordingly, the present invention also relates to a vehicle glass comprising the laminate. The vehicle glass means a windshield, a rear glass, a roof glass, a side glass, or the like for a vehicle such as a train, a train, an automobile, a ship, or an aircraft.

The haze of the laminated glass produced using the polyvinyl acetal resin film of the present invention when irradiated with light from the low-reflectance treated surface (for example, blackened surface) side is usually 2.0 or less, preferably 1 .8 or less, more preferably 1.5 or less. The haze when light is irradiated from the metallic gloss surface side of the laminated glass produced using the polyvinyl acetal resin film of the present invention is usually 3.0 or less, preferably 2.8 or less, more preferably 2.5 or less.
The haze is measured according to, for example, JIS R 3106. By using the polyvinyl acetal resin film of the present invention that does not have an adhesive layer between the polyvinyl acetal resin layer and the conductive structure, and by reducing the line width of the conductive structure, the haze is not more than the above upper limit value. Can be adjusted.

  It is preferable that the wiring of an electroconductive structure is not visually recognized from the position of a boarding person or an observer from the low-reflectance process surface side of the laminated glass produced using the polyvinyl acetal resin film of this invention. The laminated glass in the present invention is preferably used in applications where good front visibility is required, such as a vehicle windshield, because the wiring is not visually recognized. The visibility of the conductive structure is sensorially evaluated.

  When a laminated glass is produced using the plasticized polyvinyl acetal resin layer and the transparent base material and the polyvinyl acetal resin film of the present invention having a smaller dimension than those, the end of the polyvinyl acetal resin film may not be discerned visually. preferable. Since the end of the polyvinyl acetal resin film is not visually discerned, the laminated glass in the present invention is suitably used particularly in applications requiring good forward visibility such as a vehicle windshield. The visibility of the end of the polyvinyl acetal resin film is sensuously evaluated.

  In the laminated glass of the present invention, the plasticizer contained in the plasticized polyvinyl acetal resin layer usually moves to the polyvinyl acetal resin layer over time, and the amount of plasticizer contained in the plasticized polyvinyl acetal resin layer and the polyvinyl acetal The amount of plasticizer contained in the resin layer is approximately the same. In the present invention, the average plasticizer amount is preferably 18 to 35% by mass, more preferably 20 to 30% by mass, and particularly preferably 25 to 29% by mass. When the average plasticizer amount is within the above range, desired properties of the laminated glass can be easily obtained, for example, the impact on the head of the passenger at the time of collision can be reduced. The average plasticizer amount is calculated by the method described in the examples below. By adjusting the amount of plasticizer contained in the plasticized polyvinyl acetal resin layer, the thickness of the plasticized polyvinyl acetal resin layer, the amount of plasticizer contained in the polyvinyl acetal resin layer, and the thickness of the polyvinyl acetal resin layer, The average plasticizer amount can be adjusted within the above range.

  The difference between the visible light reflectance of the laminated glass in the present invention and the visible light reflectance of the laminated glass corresponding to the laminated glass in the present invention is preferably small except that the conductive structure is not included. When the difference is small, the laminated glass of the present invention is excellent in forward visibility. In particular, the laminated glass in the present invention is suitably used in applications requiring good forward visibility such as a vehicle windshield. The visible light reflectance of the laminated glass is measured according to JIS R 3106. The difference can be reduced by configuring the laminated glass so that the low reflectance treated surface of the conductive structure is disposed on the passenger side or the viewer side, or by reducing the line width of the conductive structure.

  The laminated glass in the present invention is excellent in optical properties because there is no haze derived from the adhesive for bonding the conductive structure, and when the conductive structure is imparted to the polyvinyl acetal resin layer in the present invention. Manufactured with high productivity due to high production efficiency.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this Example.

<Production of polyvinyl acetal resin layers a to m>
Polyvinyl butyral resin 1 (hereinafter referred to as “resin 1”) is melt-kneaded, or resin 1 and polyvinyl butyral resin 2 (hereinafter referred to as “resin 2”) are melt-kneaded at a mass ratio shown in Table 2. . When the polyvinyl acetal resin layer contains a plasticizer (polyvinyl acetal resin layers j and m), a predetermined amount of 3GO as a plasticizer was melt-kneaded together with the resin 1 and the resin 2. Next, the obtained melt-kneaded product was extruded into a strand shape and pelletized. The obtained pellet was melt-extruded using a single screw extruder and a T die, and a polyvinyl acetal resin layer having a smooth surface was obtained using a metal elastic roll. Table 2 shows the thicknesses of the obtained polyvinyl acetal resin layers a to m.

  Table 1 shows the physical property values of Resin 1 and Resin 2 used in the production of the polyvinyl acetal resin layers a to m.

[Example 1]
<Manufacture of polyvinyl acetal resin layer bonded with copper foil>
A copper foil having a thickness of 7 μm, which is blackened on one side, is brought into contact with the manufactured polyvinyl acetal resin layer a so that the blackened surface (hereinafter sometimes referred to as blackened surface) and the polyvinyl acetal resin layer a are in contact with each other. Stacked in the direction. Here, the visible light reflectance of the blackened surface measured according to JIS R 3106 was 5.2%. Next, the upper and lower sides of the laminate in which the polyvinyl acetal resin layer a and the copper foil are stacked are sandwiched between PET films having a thickness of 50 μm and passed between thermocompression-bonding rolls set at 120 ° C. (pressure: 0.2 MPa, speed 0. 5 m / min), and then the PET film was peeled off to obtain a polyvinyl acetal resin layer to which the copper foil was bonded.

<Manufacture of polyvinyl acetal resin film>
A dry film resist was laminated on the manufactured copper foil of the polyvinyl acetal resin layer to which the copper foil was bonded, and then an etching resistance pattern was formed using a photolithography technique. Next, a conductive structure is formed by immersing the polyvinyl acetal resin layer formed with the etching resistance pattern and bonded with a copper foil in a copper etching solution, and then the remaining photoresist layer is formed by a conventional method. Removed. This obtained the polyvinyl acetal resin film which has a polyvinyl acetal resin layer and the electroconductive structure based on copper foil arrange | positioned on the surface of the polyvinyl acetal resin layer. The obtained polyvinyl acetal resin film does not have an adhesive layer between the polyvinyl acetal resin layer and the conductive structure. The conductive structure has a copper mesh structure in which copper wires with a line width of 10 μm are arranged in a grid pattern at intervals of 500 μm inside a square of 5 cm in length and width, and the upper side and the lower side are copper with a width of 5 mm corresponding to a bus bar. It had a structure connected to the line structure.

[Examples 2 to 10]
It replaces with the polyvinyl acetal resin layer a, and arrange | positions on the surface of a polyvinyl acetal resin layer and the polyvinyl acetal resin layer like Example 1 except having used each polyvinyl acetal resin layer bj of Table 2. A polyvinyl acetal resin film having a conductive structure based on copper foil was obtained.

[Example 11]
Instead of the polyvinyl acetal resin layer a, a polyvinyl acetal resin layer c was used, and a copper foil having a thickness of 7 μm, on which one side was blackened, was stacked in such a direction that the metal glossy surface and the polyvinyl acetal resin layer c were in contact with each other Except for this, a polyvinyl acetal resin film having a polyvinyl acetal resin layer and a conductive structure based on copper foil disposed on the surface of the polyvinyl acetal resin layer was obtained in the same manner as in Example 1. Here, the visible light reflectance of the metallic glossy surface measured according to JIS R 3106 was 63%.

[Example 12]
It replaced with the polyvinyl acetal resin layer a, and obtained the polyvinyl acetal resin layer to which the copper foil was joined like Example 1 except having used the polyvinyl acetal resin layer c. Next, a polyvinyl acetal resin layer and a polyvinyl acetal were produced in the same manner as in Example 1 except that the produced polyvinyl acetal resin layer bonded with copper foil was used and the line width of the photomask used for photolithography was changed. The polyvinyl acetal resin film which has the conductive structure based on copper foil arrange | positioned on the surface of the resin layer was obtained. The conductive structure has a copper mesh structure in which copper wires with a line width of 5 μm are arranged in a grid pattern at intervals of 500 μm inside a square of 5 cm in length and width, and the upper side and the lower side are copper with a width of 5 mm corresponding to a bus bar. It had a structure connected to the line structure.

[Example 13]
A polyvinyl acetal resin layer and a conductive structure based on copper foil disposed on the surface of the polyvinyl acetal resin layer in the same manner as in Example 12 except that the line width of the copper wire was adjusted to 20 μm; A polyvinyl acetal resin film having was obtained. The conductive structure has a copper mesh structure in which copper wires having a line width of 20 μm are arranged in a grid pattern at intervals of 1000 μm inside a square of 5 cm in length and width, and the upper side and the lower side are copper having a width of 5 mm corresponding to a bus bar. It had a structure connected to the line structure.

[Example 14]
A polyvinyl acetal resin layer and a conductive structure based on copper foil disposed on the surface of the polyvinyl acetal resin layer in the same manner as in Example 12 except that the line width of the copper wire was adjusted to 30 μm, and A polyvinyl acetal resin film having was obtained. The conductive structure has a copper mesh structure in which copper wires with a line width of 30 μm are arranged in a grid at intervals of 1500 μm inside a square of 5 cm in length and width, and the upper side and the lower side are copper with a width of 5 mm corresponding to a bus bar. It had a structure connected to the line structure.

[Example 15]
A polyvinyl acetal resin layer and a conductive structure based on a copper foil disposed on the surface of the polyvinyl acetal resin layer in the same manner as in Example 12 except that the line width of the copper wire was adjusted to 40 μm; A polyvinyl acetal resin film having was obtained. The conductive structure has a copper mesh structure in which copper wires with a line width of 40 μm are arranged in a grid pattern at intervals of 2000 μm inside a square of 5 cm in length and width, and the upper side and the lower side are copper with a width of 5 mm corresponding to a bus bar. It had a structure connected to the line structure.

[Example 16]
It replaced with the polyvinyl acetal resin layer a, and obtained the polyvinyl acetal resin layer to which the copper foil was joined like Example 1 except having used the polyvinyl acetal resin layer c. Next, a polyvinyl acetal resin layer and a polyvinyl acetal resin were produced in the same manner as in Example 1 except that the manufactured polyvinyl acetal resin layer to which the copper foil was bonded was used and the structure of the photomask used for photolithography was changed. A polyvinyl acetal resin film having a conductive structure based on copper foil disposed on the surface of the layer was obtained. The conductive structure has a structure in which copper wires having a line width of 10 μm are linearly arranged at intervals of 500 μm, and both ends of each straight line are connected to a copper wire structure having a width of 5 mm corresponding to a bus bar. It was.

[Example 17]
It replaced with the polyvinyl acetal resin layer a, and obtained the polyvinyl acetal resin layer to which the copper foil was joined like Example 1 except having used the polyvinyl acetal resin layer c. Next, a polyvinyl acetal resin layer and a polyvinyl acetal resin were produced in the same manner as in Example 1 except that the manufactured polyvinyl acetal resin layer to which the copper foil was bonded was used and the structure of the photomask used for photolithography was changed. A polyvinyl acetal resin film having a conductive structure based on copper foil disposed on the surface of the layer was obtained. The conductive structure has a structure in which copper wires having a line width of 10 μm are arranged in a wavy shape at intervals of 500 μm, and both ends of each wavy line are connected to a copper wire structure having a width of 5 mm corresponding to a bus bar. It was.

[Example 18]
It replaced with the polyvinyl acetal resin layer a, and obtained the polyvinyl acetal resin layer to which the copper foil was joined like Example 1 except having used the polyvinyl acetal resin layer c. Next, a polyvinyl acetal resin layer and a polyvinyl acetal resin were produced in the same manner as in Example 1 except that the manufactured polyvinyl acetal resin layer to which the copper foil was bonded was used and the structure of the photomask used for photolithography was changed. A polyvinyl acetal resin film having a conductive structure based on copper foil disposed on the surface of the layer was obtained. The conductive structure has a structure in which copper wires having a line width of 10 μm are arranged in a zigzag line at 500 μm intervals, and both ends of each zigzag line are connected to a copper wire structure having a width of 5 mm corresponding to a bus bar. Had.

[Example 19]
Conductivity based on copper foil disposed on the surface of the polyvinyl acetal resin layer and the polyvinyl acetal resin layer in the same manner as in Example 1 except that the polyvinyl acetal resin layer k was used instead of the polyvinyl acetal resin layer a. A polyvinyl acetal resin film having a conductive structure was obtained.

[Example 20]
Conductivity based on copper foil disposed on the surfaces of the polyvinyl acetal resin layer and the polyvinyl acetal resin layer in the same manner as in Example 1 except that the polyvinyl acetal resin layer 1 was used instead of the polyvinyl acetal resin layer a. A polyvinyl acetal resin film having a conductive structure was obtained.

[Comparative Example 1]
Conductivity based on copper foil disposed on the surfaces of the polyvinyl acetal resin layer and the polyvinyl acetal resin layer in the same manner as in Example 1 except that the polyvinyl acetal resin layer m was used instead of the polyvinyl acetal resin layer a. A polyvinyl acetal resin film having a conductive structure was obtained.

[Comparative Example 2]
When a copper foil is bonded to the polyvinyl acetal resin layer c, a polyvinyl acetal resin is obtained in the same manner as in Example 3 except that it is bonded using an acrylate adhesive instead of being bonded using a thermocompression-bonding roll. The polyvinyl acetal resin film which has the layer and the electroconductive structure based on copper foil arrange | positioned on the surface of the polyvinyl acetal resin layer was obtained.

[Comparative Example 3]
Conductivity based on the PET film and the copper foil disposed on the surface of the PET film in the same manner as in Comparative Example 2 except that a PET film (PET layer, thickness 50 μm) was used instead of the polyvinyl acetal resin layer c. A PET film having a structure was obtained.

<Evaluation of film forming property of polyvinyl acetal resin layer>
In Examples 1 to 5, the film forming property when the polyvinyl acetal resin or the polyvinyl acetal resin mixture was melt-extruded by an extruder was evaluated according to the following criteria. The results are shown in Table 2.
A The film-forming property was very good.
B The film forming property was good.
C Coloring and generation of decomposition gas occurred, but film formation was possible.
D Film formation was impossible.

<Production of laminated glass>
The polyvinyl acetal resin film having the conductive structure obtained in Examples 1 to 20 and Comparative Examples 1 and 2, and the PET film having the conductive structure obtained in Comparative Example 3 were cut into a length of 5 cm and a width of 5 cm, respectively. And placed on a glass having a length of 10 cm, a width of 10 cm, and a thickness of 3 mm. At this time, the film was disposed such that the surface having no conductive structure was in contact with the glass and the conductive structure was near the center of the glass. Next, affix the electrodes (copper foil tape with conductive adhesive) to each bus bar (5 mm wide copper wire) at both ends of the conductive structure so that each electrode end protrudes out of the glass. It was. Further, a plasticized polyvinyl acetal resin layer having a length of 10 cm, a width of 10 cm, and a thickness of 0.76 mm [a polyvinyl butyral resin having a hydroxyl group content of 20.0 mass% and a viscosity average polymerization degree of 1700 (72 mass%); 3GO (28 mass% inclusive)] An automobile windshield intermediate film and a glass having a length of 10 cm, a width of 10 cm, and a thickness of 3 mm were stacked.
Subsequently, this was put in a vacuum bag and reduced in pressure for 15 minutes at room temperature using a vacuum pump. Then, the temperature was raised to 100 ° C. while reducing the pressure, and the mixture was heated as it was for 60 minutes. After the temperature was lowered, the pressure was returned to normal pressure, and the laminated glass after prelaminating was taken out.
Thereafter, this was put into an autoclave and treated at 140 ° C. and 1.2 MPa for 30 minutes to produce a laminated glass.

<Evaluation of state of conductive structure (lattice, straight, wavy or zigzag)>
The state of the conductive structure after pre-lamination and after autoclaving was visually observed using a loupe, and the presence or absence of wiring deformation and disconnection was evaluated according to the following criteria. The results are shown in Table 2 and Table 4.
A Deformation and disconnection were not recognized.
B Partial deformation was observed, but no disconnection was observed.
C Slight disconnection was observed.
D Disconnection was remarkable.

<Evaluation of electrical conductivity>
The resistance between the two electrodes attached to each bus bar was measured with a tester. The resistance value was measured before and after the laminated glass was produced, and the conductivity was evaluated according to the following criteria. The results are shown in Table 2 and Table 4.
A The resistance value after production of laminated glass is extremely good, within 1.5 times the resistance value before production of laminated glass.
B Resistance value after production of laminated glass exceeds 1.5 times the resistance value before production of laminated glass, and good within 2 times.
C The resistance value after producing laminated glass is more than twice and less than 4 times the resistance value before producing laminated glass, but is practical.
D The resistance value after production of laminated glass exceeds 4 times the resistance value before production of laminated glass, impractical.

<Measurement of haze>
The polyvinyl acetal resin film having the conductive structure obtained in Examples 1 to 20 and Comparative Examples 1 and 2, and the PET film having the conductive structure obtained in Comparative Example 3 were cut into a length of 5 cm and a width of 5 cm, respectively. And placed on a glass having a length of 5 cm, a width of 5 cm and a thickness of 3 mm. At this time, it arrange | positioned in the direction which the surface which does not have the electroconductive structure of the said film contacts glass. On top of that, as a plasticized polyvinyl acetal resin layer, a length of 5 cm, a width of 5 cm, a thickness of 0.76 mm [a polyvinyl butyral resin having a hydroxyl group content of 20.0 mass% and a viscosity average polymerization degree of 1700 (72 mass%) and 3GO ( 28% by mass)] An intermediate film for an automobile windshield and a glass having a length of 5 cm, a width of 5 cm, and a thickness of 3 mm were stacked.
Subsequently, this was put in a vacuum bag and reduced in pressure for 15 minutes at room temperature using a vacuum pump. Then, the temperature was raised to 100 ° C. while reducing the pressure, and the mixture was heated as it was for 60 minutes. After the temperature was lowered, the pressure was returned to normal pressure, and the laminated glass after prelaminating was taken out.
Thereafter, this was put into an autoclave and treated at 140 ° C. and 1.2 MPa for 30 minutes to produce a laminated glass.
For each of the laminated glass having the obtained conductive structure, the haze when light is irradiated from the blackened surface side and the haze when light is irradiated from the metallic glossy surface side are measured using a haze meter. It measured according to JISR3106. The results are shown in Table 2.

<Sensory evaluation of visibility of conductive structure>
When the laminated glass with the blackened surface side facing the observer is placed at a position approximately 50 cm away from the observer, the copper wire of the conductive structure can be visually recognized when the observer looks at 5 m ahead through the glass. Whether or not was evaluated functionally according to the following criteria. The results are shown in Table 2.
A Very good with little concern.
B: I was a little worried when I changed the focus.
C A little worried, but practical.
D Worrying and impractical.

<Sensory evaluation of visibility of end of polyvinyl acetal resin film>
After leaving the laminated glass produced according to the above <Production of laminated glass> at room temperature for 2 weeks, whether or not the end portion of the polyvinyl acetal resin film having a size smaller than that of the intermediate film for an automobile windshield can be visually determined is described below. Sensory evaluation was performed based on the criteria. The results are shown in Table 2.
A It is very good because it cannot be distinguished at all.
B: There was a part that could be discriminated if you look closely, but it was good.
C Although it was discernable if you look closely, it is practical.
D Clearly distinguishable and impractical.

Ａ（質量％）：可塑化ポリビニルアセタール樹脂層の可塑剤量
ａ（ｍｍ）：可塑化ポリビニルアセタール樹脂層の厚み
Ｂ（質量％）：ポリビニルアセタール樹脂層の可塑剤量
ｂ（ｍｍ）：ポリビニルアセタール樹脂層の厚み <Amount of average plasticizer>
The plasticizer contained in the polyvinyl acetal resin layer is transferred to the polyvinyl acetal resin layer as the plasticizer contained in the automobile windshield intermediate film as the plasticized polyvinyl acetal resin layer. The amount of plasticizer (calculated value) when the amount was the same as the amount was calculated according to the following formula. The results are shown in Table 2.

A (mass%): plasticizer amount of plasticized polyvinyl acetal resin layer a (mm): thickness of plasticized polyvinyl acetal resin layer B (mass%): plasticizer amount of polyvinyl acetal resin layer b (mm): polyvinyl acetal Resin layer thickness

  As shown in Table 2, when the amount of the plasticizer in the polyvinyl acetal resin layer is within the range defined in the present invention, there is little deformation and disconnection of the conductive structure during the production of the laminated glass, Electrical conductivity was good. Moreover, when the laminated glass produced using the polyvinyl acetal resin film of the present invention that does not have an adhesive layer between the polyvinyl acetal resin layer and the conductive structure is irradiated with light from the blackened surface side Both the haze and the haze when irradiated with light from the metallic glossy surface showed good values. On the other hand, when the amount of the plasticizer was larger than the amount specified in the present invention (Comparative Example 1), the conductivity was not practical. When having an adhesive layer between the polyvinyl acetal resin layer and the conductive structure (Comparative Example 2), and having an adhesive layer between the PET layer and the conductive structure (Comparative Example 3), The haze value was too high. Further, in Comparative Example 3, the film end portion was clearly discriminated. Such a laminated glass is not suitably used in applications where good forward visibility is required.

[Examples 21 to 24]
<Evaluation of visible light reflectance of laminated glass>
In Examples 21, 22 and 24, the laminated glass for visible light reflectance measurement described later was produced using the polyvinyl acetal resin film produced in Example 3 and the laminated glass composition shown in Table 3. In Example 23, the polyvinyl acetal resin film produced in Example 11 was used, and a laminated glass for visible light reflectance measurement described later was produced with the configuration of the laminated glass shown in Table 3. Specifically, in the configuration of the laminated glass shown in Table 3, 5 cm long, 5 cm wide, 3 mm thick glass, 5 cm long, 5 cm wide polyvinyl acetal resin film, 5 cm long as a plasticized polyvinyl acetal resin layer An intermediate film for an automobile windshield having a width of 5 cm and a thickness of 0.76 mm [including a polyvinyl butyral resin (72% by mass) having a hydroxyl group content of 20.0% by mass and a viscosity average polymerization degree of 1700 and 3GO (28% by mass)] Were placed in a vacuum bag, put in a vacuum bag, reduced in pressure at room temperature for 15 minutes using a vacuum pump, then heated up to 100 ° C. with reduced pressure, and heated for 60 minutes. After the temperature was lowered, the pressure was returned to normal pressure, and the laminated glass after prelaminating was taken out. Thereafter, this was put into an autoclave and treated at 140 ° C. and 1.2 MPa for 30 minutes to produce a laminated glass. The visible light reflectance was measured according to JIS R 3106 when light was irradiated from the inner glass (assuming the passenger side) of the obtained laminated glass for visible light reflectance measurement. The results are shown in Table 3.

[Examples 25 to 28]
<Evaluation of the effect of the temperature at the time of joining the polyvinyl acetal resin layer and the copper foil on the peel strength, the state of the conductive structure and the electrical conductivity>
In the same manner as in Example 1 except that the A4 size polyvinyl acetal resin layer c was stacked on the A4 size copper foil, and the end 8 cm was not heat-pressed at the temperature shown in Table 4, the copper foil was A bonded polyvinyl acetal resin layer was obtained. The obtained resin layer is cut into strips of 1 cm width so that the end portion that is not thermocompression-bonded is a portion sandwiched between chucks of a tensile tester, and a tensile test is performed at a distance between chucks of 4 cm and a pulling speed of 100 mm / min. The peel force for every 20 mm was output, and the average value was defined as the peel strength.
Moreover, the state (lattice shape) of the conductive structure and the evaluation of the electrical conductivity were carried out in the same manner as in Example 1 except that the copper foil was joined by thermocompression bonding at the temperatures shown in Table 4. The results are shown in Table 4.

  As described above, when a polyvinyl acetal resin film was produced according to the method of the present invention, the production efficiency when imparting a conductive structure was high, and thus a polyvinyl acetal resin film could be produced with high productivity. In addition, since no adhesive is used when bonding the copper foil to the polyvinyl acetal resin layer, the laminated glass produced using the polyvinyl acetal resin film of the present invention adheres the conductive structure to the polyvinyl acetal resin layer. Therefore, no haze derived from the adhesive used for this purpose occurs. Furthermore, as shown in Table 4, when the polyvinyl acetal resin layer of the present invention was used, no disconnection was observed in the conductive structure after pre-lamination and after autoclaving, and good electrical conductivity was obtained. A sufficiently high peel strength was also obtained.

Claims (15)

  A polyvinyl acetal resin film having a polyvinyl acetal resin layer and a conductive structure based on metal foil disposed on or inside the polyvinyl acetal resin layer, wherein the amount of plasticizer in the polyvinyl acetal resin layer is polyvinyl Polyvinyl acetal resin film is 0 to 20% by mass based on the total mass of the resin composition constituting the acetal resin layer, and the polyvinyl acetal resin film does not have an adhesive layer between the polyvinyl acetal resin layer and the conductive structure. Acetal resin film.   The polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin layer was measured at 20 ° C. and 30 rpm using a Brookfield type (B type) viscometer. The polyvinyl acetal resin film of Claim 1 whose viscosity of 1 (mass ratio) solution is 200 mPa * s or more.   The polyvinyl acetal resin film according to claim 1 or 2, wherein the polyvinyl acetal resin film has a thickness of 10 to 350 µm.   The polyvinyl acetal resin film in any one of Claims 1-3 whose thickness of the said electroconductive structure is 1-30 micrometers.   The polyvinyl acetal resin film according to claim 1, wherein the conductive structure is made of copper or silver.   The polyvinyl acetal resin film according to any one of claims 1 to 5, wherein the conductive structure has a linear shape, a lattice shape, or a net shape.   The polyvinyl acetal resin film of Claim 6 whose line | wire width of the electroconductive structure which comprises the above-mentioned linear form, a grid | lattice form, or a net-like shape is 1-30 micrometers.   The polyvinyl acetal resin film according to any one of claims 1 to 7, wherein one surface or both surfaces of the conductive structure is subjected to low reflectance treatment.   The polyvinyl acetal resin film according to claim 8, wherein the low reflectance treatment is a blackening treatment.   The process of joining a metal foil and a polyvinyl acetal resin layer, and the process of forming an electroconductive structure from the polyvinyl acetal resin layer with a metal foil obtained at the said process are included in any one of Claims 1-9. A method for producing a polyvinyl acetal resin film.   The laminated body which has the polyvinyl acetal resin film in any one of Claims 1-9 between several transparent base materials.   The laminated body which has the polyvinyl acetal resin film in any one of Claims 1-9, and the plasticization polyvinyl acetal resin layer between several transparent base materials.   The laminate according to claim 11 or 12, wherein the transparent substrate is glass.   The difference between the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the polyvinyl acetal resin film and the amount of hydroxyl groups of the polyvinyl acetal resin in the resin composition constituting the plasticized polyvinyl acetal resin layer is a vinyl alcohol unit. The laminate according to claim 12, wherein the difference in mass% is 4 mass% or less.   The glass for vehicles which consists of a laminated body in any one of Claims 11-14.