WO2016017452A1

WO2016017452A1 - Method for producing laminated sheet

Info

Publication number: WO2016017452A1
Application number: PCT/JP2015/070501
Authority: WO
Inventors: 裕貴木上; 弘宣玉井; 翠東城
Original assignee: 日東電工株式会社
Priority date: 2014-07-30
Filing date: 2015-07-17
Publication date: 2016-02-04
Also published as: JP2016032869A; TW201604017A; JP5758031B1

Abstract

Provided is a highly productive method for producing a laminated sheet in which performance qualities such as interlayer adhesion are improved. The present invention provides a method for producing a laminated sheet provided with a first resin layer, a second resin layer, and an elastic layer that is arranged between the first resin layer and the second resin layer. The method comprises: a laminating step for forming a laminate in which an elastic layer-forming composition is arranged between a first resin film that serves as the first resin layer and a second resin film that serves as the second resin layer; and a curing step in which, continuing from the lamination step, the elastic layer-forming composition is cured to form the elastic layer. In addition, the curing step is preferably a heating step. The elastic layer-forming composition has fluidity in the laminating step environment prior to the curing thereof and is non-volatile in the curing step environment.

Description

Method for producing laminated sheet

The present invention relates to a method for manufacturing a laminated sheet. This application claims priority based on Japanese Patent Application No. 2014-155503 filed on Jul. 30, 2014, the entire contents of which are incorporated herein by reference.

A laminated sheet having an elastic layer is widely used as a sealing material, an impact absorbing material, a functional material, and the like in the fields of automobiles, architecture, electronic equipment, medicine, and the like. For example, Patent Document 1 discloses a laminated sheet including an elastic layer and a protective film that sandwiches the elastic layer from both sides, as an electronic device inspection contact sheet disposed between the electronic device and the inspection circuit board. ing. Patent Documents 2 to 6 are documents disclosing methods for manufacturing and laminating a laminated sheet having an elastic layer.

Japanese Patent Application Publication No. 2004-101410 Japanese Patent Application Publication No. 10-264344 Japanese Patent Application Publication No. 2004-269786 Japanese Patent Application Publication No. 7-138381 Japanese Patent Application Publication No. 8-143834 Japanese Patent Application Publication No. 2008-88408

As described above, various types of laminated sheets in which an elastic layer is disposed between two resin layers have been proposed, but higher performance and higher quality are required. Typically, there is a demand for a laminated sheet having improved adhesion (interlayer adhesion) between layers constituting the laminated sheet, appearance, thickness accuracy, and the like. For example, the electronic device inspection contact sheet of Patent Document 1 is manufactured by laminating a protective film on both sides of an elastic layer and then heating, but is already laminated using a cured elastic layer. The interlayer adhesion has a limit. In that sense, Patent Document 2 can be said to be a similar technique. In the method of Patent Document 3, the solvent is volatilized when the rubber solution sandwiched between two supports is dried. Since this volatile component remains between the layers, interlayer adhesion between the obtained elastic layer and the support is not so high. There is also a problem that the volatilization of the solvent during drying adversely affects the appearance of the laminated sheet. Patent Document 4 employs a technique in which a laminate in which an uncrosslinked product is sandwiched between two films is wound into a roll, and then the uncrosslinked product is crosslinked. It is not stable until it is made, and the unevenness of interlayer adhesion and thickness accuracy is large. Patent Document 5 discloses a method in which a primer layer is interposed between a resin film and an elastic layer. This method is basically a method applied to one side of an elastic layer. In Patent Document 6, an ultraviolet curable pressure-sensitive adhesive is provided between a substrate or the like and the release film by irradiating ultraviolet rays with the ultraviolet curable pressure-sensitive adhesive composition sandwiched between the base material or the release film and the release film. A laminated body provided with a layer (elastic layer) is produced. Thus, in the performance enhancement and quality improvement of a laminated sheet, the restrictions by a manufacturing method are still large. It would be beneficial if a laminated sheet with improved performance qualities such as interlayer adhesion compared to the prior art can be provided by a method with excellent productivity.

The present invention was created in view of the above circumstances, and an object of the present invention is to provide a method for producing a laminated sheet with improved performance quality such as interlayer adhesion, which is excellent in productivity.

According to the present invention, there is provided a method for producing a laminated sheet comprising a first resin layer, a second resin layer, and an elastic layer disposed between the first resin layer and the second resin layer. . This method includes a laminating step of forming a laminate in which an elastic layer forming composition is disposed between a first resin film to be the first resin layer and a second resin film to be the second resin layer; Followed by a curing step of curing the elastic layer forming composition to form an elastic layer after the laminating step. The composition for forming an elastic layer before curing has fluidity in the lamination process environment and is non-volatile in the curing process environment.
As described above, by forming a laminate in which the elastic layer forming composition is disposed between two resin films in a state where the elastic layer forming composition has fluidity, and subsequently curing, A laminated sheet excellent in interlayer adhesion can be produced efficiently. Since the elastic layer forming composition is non-volatile, problems caused by vaporization of volatile components in the production process (for example, a decrease in interlayer adhesion and a decrease in the appearance of the laminated sheet) are prevented or suppressed. Moreover, the said manufacturing method is also a method excellent in productivity applicable to continuous production, such as a roll-to-roll system. Therefore, according to the manufacturing method disclosed herein, the performance quality of the laminated sheet can be improved by a method with excellent productivity.

In a preferred embodiment of the technology disclosed herein, the curing step is a heating step. Normally, volatile components in the composition are vaporized during heating, which may deteriorate the interlaminar adhesion or deteriorate the appearance, but the elastic layer forming composition disclosed herein is non-volatile, so such a problem The occurrence of is prevented or suppressed. Therefore, in the embodiment in which the elastic layer forming composition is cured by heating, the effects of the technique disclosed herein are preferably exhibited.

In a preferred aspect of the technology disclosed herein, the heating step includes: a preheating step of heating the elastic layer forming composition at a temperature T _P ° C; and the elastic layer forming composition; And a main heating step of heating at a temperature T _M ° C. (where T _P <T _M is satisfied). By performing preheating at a lower temperature than the main heating, the composition can be reduced in viscosity before being cured. As a result, air and trace volatile components that can be contained in the composition can easily escape from the composition to the outside of the laminated sheet, and deterioration of interlayer adhesion and appearance are prevented.

In a preferred aspect of the technology disclosed herein, the laminating step includes: supplying the first resin film to a first roll; and arranging the second resin film so as to face the first roll. And supplying the elastic layer forming composition between the first resin film supplied to the first roll and the second resin film supplied to the second roll. Including. By comprising in this way, the laminated structure provided with a 1st resin film, an elastic layer, and a 2nd resin film is implement | achieved preferably. Further, the thickness of the elastic layer can be adjusted with high accuracy by setting the interval between the two rolls.

It is explanatory drawing which shows typically the manufacturing method of the lamination sheet which concerns on embodiment.

Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than the matters specifically mentioned in the present specification and necessary for the implementation of the present invention are based on the teachings on the implementation of the invention described in the present specification and the common general technical knowledge at the time of filing. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.
In the following drawings, members / parts having the same action may be described with the same reference numerals, and redundant descriptions may be omitted or simplified. Further, the embodiments described in the drawings are schematically illustrated for clearly explaining the present invention, and do not necessarily accurately represent the size and scale of the laminated sheet of the present invention actually provided as a product. .

As schematically shown in FIG. 1, in the method for manufacturing the laminated sheet 1 according to the first embodiment, the first resin film 31 that becomes the first resin layer 21 and the second resin film 32 that becomes the second resin layer 22. The laminated body 5 in which the elastic layer forming composition 15 is disposed is formed (lamination process).

Specifically, the first resin film 31 and the second resin film 32 are prepared in advance, for example, in a roll state, and set in the laminated sheet manufacturing apparatus 100. And in the lamination sheet manufacturing apparatus 100 provided with the 1st roll 51 and the 2nd roll 52 which are arrange | positioned at predetermined intervals up and down, the 1st resin film 31 is supplied to the 1st roll 51 arrange | positioned below. The second resin film 32 is supplied to the second roll 52 disposed above. The 1st roll 51 and the 2nd roll 52 are arrange | positioned so that the roll surface may face each other, The 1st resin film 31 and the 2nd resin film 32 are the 1st roll 51 and the 2nd roll 52 Sent from one direction to the other. In FIG. 1, the first resin film 31 and the second resin film 32 are sent leftward in a horizontal state.

In the above configuration, the elastic layer forming composition 15 is supplied between the first resin film 31 supplied to the first roll 51 and the second resin film 32 supplied to the second roll 52 (specifically, throw into. At this time, the elastic layer forming composition 15 can be in close contact with the first resin film 31 and the second resin film 32 by setting the arrangement (interval) between the first roll 51 and the second roll 52. Further, after curing, the elastic layer 10 can have a high thickness accuracy. In this way, the laminate 5 in which the elastic layer forming composition 15 is disposed between the first resin film 31 and the second resin film 32 is obtained. The supply amount (typically, the input amount) of the elastic layer forming composition 15 is not particularly limited, and may be set according to the thickness of the elastic layer and the like.

The supply (typically, charging) timing of the elastic layer forming composition 15 is not particularly limited as long as it is before lamination. For example, after applying the elastic layer forming composition 15 on the first resin film 31 located below, the desired distance is obtained using the arrangement interval between the first resin film 31 and the second resin film 32. It is also possible to adjust. Moreover, in this embodiment, although the 1st roll 51 and the 2nd roll 52 are both non-heating rolls, you may use a heating roll from viewpoints, such as the external appearance of a lamination sheet. The method for supplying the elastic layer forming composition 15 between the first resin film 31 and the second resin film 32 (which may be a charging method) is not particularly limited, and is a comma coater, a die coater, or a roll. A known coater such as a coater or a bar coater may be used.

After the above-described laminating step, the elastic layer forming composition 15 is subsequently cured to form the elastic layer 10 (curing step). Here, “continue” means that it does not include an operation of winding the laminate 5 on a roll after the lamination step and before the curing step. There is no time limit between the lamination process and the curing process, but the time from the end of the lamination process to the start of the curing process is generally within 30 minutes (for example, within 10 minutes, typically within 5 minutes). It is appropriate to do. It is preferable not to include other steps (for example, storage) between the lamination step and the curing step. For example, like the roll-to-roll method, it is preferable to continuously perform the lamination and curing process without stopping the laminated body 5. In this embodiment, the conveyance speed of the laminated body 5 is set to an appropriate range in consideration of the lamination process, the curing process, and the like. Usually, a conveyance speed can be adjusted according to the hardening conditions (for example, hardening temperature and time) of the composition 15 for elastic layer formation, the size (length) of a heater, etc.

The laminated body 5 in which the first resin film 31, the elastic layer forming composition 15 and the second resin film 32 are laminated in this order is specifically unidirectional by the first roll 51 and the second roll 52. To reach the curing means 70. By this curing means 70, the elastic layer forming composition 15 is cured while being sandwiched between the first resin film 31 and the second resin film 32 to become the elastic layer 10. In this embodiment, the curing process is a heating process, and a heater 71 is used as the curing means 70. Therefore, the elastic layer forming composition 15 is a thermosetting composition. Since the elastic layer forming composition 15 has fluidity at the start of the curing step, the elastic layer forming composition 15 is cured in close contact with the first resin film 31 and the second resin film 32. As a result, the formed elastic layer 10 is firmly adhered to the first resin layer 21 and the second resin layer 22. The conditions for the curing step are set based on the composition of the elastic body forming composition 15, the transport speed of the laminate 5, and the like. Note that the curing means 70 can be an infrared irradiator, an ultraviolet (UV) irradiator, a high humidity environment, or the like, depending on the curing mode of the elastic layer forming composition 15.

What is necessary is just to set the temperature and time of a heating process based on the hardening temperature (typically crosslinking temperature) of the elastic layer forming composition 15, hardening time (for example, 90% hardening time), etc. For example, the time t of the heating step can be set to be longer than the 90% curing time of the elastic layer forming composition 15 at the temperature T (° C.) of the heating step. From the viewpoint of completing the curing process in a short time, the temperature T (° C.) of the heating process is such that the 90% curing time of the elastic layer forming composition 15 is 5 minutes (more preferably 3 minutes, typically 1). It is preferable that it is higher than the temperature (cure temperature) T _x (° C.). Specifically, the heating temperature T (° C.) in the heating step is preferably 100 ° C. or higher (eg, 120 ° C. to 300 ° C., typically 140 ° C. to 200 ° C.). The time t of the heating step is preferably about 10 seconds to 10 minutes (eg, 30 seconds to 5 minutes, typically 1 minute to 3 minutes) from the viewpoint of productivity and the like. The 90% curing time and cure temperature can be measured using a commercially available curast meter. The 90% curing time is the time required to reach 90% of the torque value (typically the maximum torque value) when there is no torque change in the measurement with a curast meter. Moreover, the time of a heating process is the time from the start of a heating process to completion | finish, and when a laminated body is moving, it is the time required for one point of a laminated body to pass a heating process. Moreover, as the temperature of the heating step, for convenience, the temperature of the laminate surface or the atmospheric temperature (for example, the temperature in the dryer) in which the heating step is performed may be employed.

In this embodiment, a plurality of heaters 71 are installed as the curing means 70 along the feeding direction of the laminate 5 (the direction indicated by the arrow in FIG. 1). The heater 71 is disposed below and above the stacked body 5. By disposing the curing means 70 above and below the laminate 5, uniform curing of the elastic layer 10 is realized. The heater 71 is not particularly limited, and a heater such as a known hot air dryer may be used. There is no restriction | limiting in particular in the number of the heaters 71, and it is 1 or 2 or more. The plurality of heaters 71 may be housed in one chamber.

In addition, also when the hardening of the composition for elastic layer formation is not heat hardening but other hardening forms, such as UV hardening, it is preferable to perform a heating process before a hardening process from a viewpoint of a lamination sheet external appearance. As the heating conditions in that case, the above-mentioned heating process conditions can be preferably applied.

A laminated sheet comprising the first resin layer 21, the second resin layer 22, and the elastic layer 10 disposed between the first resin layer 21 and the second resin layer 22 through the above-described lamination process and curing process. 1 is obtained. This laminated sheet 1 is excellent in adhesion between the respective layers, and is manufactured by a method excellent in productivity as described above.

The laminated sheet 1 produced through the curing step may be wound around a roll 80 (recovery step) or may be cut into a desired size as it is. Moreover, as described in Patent Document 1, as necessary, the laminated sheet 1 may be subjected to any processing step such as forming a through hole.

Next, the material of the laminated sheet will be described. The composition for forming an elastic layer before lamination has fluidity in a lamination process environment. The lamination process environment is not particularly limited, but is usually an atmospheric environment of approximately 5 ° C. to 40 ° C. (for example, 20 ° C. to 30 ° C.), and in such an environment, the elastic layer forming composition exhibits fluidity. Can have. Typically, the elastic layer forming composition is a liquid composition having fluidity in a normal temperature (25 ° C.) and normal pressure environment. Liquid forms include syrup, slurry, and paste.

The elastic layer forming composition has a viscosity in the above-described environment, and typically has a viscosity of a predetermined level or more. The viscosity of the composition for forming an elastic layer can usually be set to about 0.1 Pa · s or more from the viewpoints of coating properties, lamination properties, and the like. The viscosity is preferably about 1 Pa · s or more (for example, 10 Pa · s or more, typically 30 Pa · s or more). The upper limit of the viscosity is suitably about 500 Pa · s or less (for example, 300 Pa · s or less, typically 100 Pa · s or less) from the viewpoint of coating properties and the like. The viscosity is a viscosity at 30 ° C., and after heating the elastic layer forming composition in a warm bath at 30 ° C. for 1 hour, at the same temperature, using a commercially available B-type viscometer, the viscosity of the object to be measured is adjusted. Measurements can be made using a suitable rotor and rotational speed.

The elastic layer forming composition is non-volatile in the curing process environment. Here, the non-volatile composition means that the proportion of volatile components (typically solvents) that vaporize in the curing process environment is less than 10% by weight (eg less than 3% by weight, typically less than 1% by weight). ). In the elastic layer forming composition, the proportion of the volatile component that vaporizes in the curing process environment is preferably less than 0.1% by weight (for example, less than 0.01% by weight), and may be substantially free of the volatile component. More preferred. Typically, the elastic layer forming composition is a solvent-free composition substantially free of a solvent. In this case, the elastic layer forming composition is substantially composed of only a non-volatile component. The curing process environment is not particularly limited, but may be a substantially atmospheric pressure environment of approximately 60 ° C. or higher (eg, 100 ° C. to 300 ° C., typically 120 ° C. to 200 ° C.). In such an environment, the elastic layer forming composition may be non-volatile.

The above-mentioned composition for forming an elastic layer is a curable composition that is cured by a curing treatment to become an elastic layer. In this embodiment, the elastic layer forming composition is a thermosetting composition, but is not limited thereto. Curing may be, for example, active energy ray curing (UV curing, gamma ray curing, electron beam curing, etc.), moisture curing, etc., and can typically be done by a crosslinking reaction. From the viewpoint of productivity, the elastic layer forming composition is preferably a thermosetting type or a photocurable type, and particularly preferably a thermosetting type. Further, the composition may be a one-component type or a two-component type.

The elastic layer forming composition is typically a curable resin composition as a main component (a component that is contained most in the composition, preferably a component that is contained in excess of 50% by weight; the same shall apply hereinafter). And an uncrosslinked product (uncrosslinked composition) containing at least a polymer and a crosslinking agent capable of undergoing a crosslinking reaction with the polymer. Here, the uncrosslinked product includes not only those in which the crosslinking reaction has not substantially started, but also partially crosslinked products that have been partially crosslinked. The polymer and the crosslinking agent are not particularly limited, and may be appropriately selected from known ones according to characteristics required for the elastic layer after curing. The crosslinking agent is a thermal crosslinking agent when the elastic layer forming composition is a thermosetting composition. In addition, when the composition for elastic layer formation is an active energy ray hardening type, inclusion of a crosslinking agent is not essential. In that case, the composition for forming an elastic layer may be a partially reacted product (partially polymerized product). If necessary, the elastic layer forming composition may be a tackifier, a leveling agent, a crosslinking aid (catalyst), a plasticizer, a softener, a filler, a colorant (pigment, dye, etc.), a dispersant, a flame retardant. Further, various additives common in this field such as processing aids, antistatic agents, anti-aging agents, ultraviolet absorbers, antioxidants, and light stabilizers may be contained.

Commercially available products may be used as the elastic layer forming composition. Alternatively, a polymer capable of exhibiting desired characteristics is synthesized, a crosslinking agent capable of crosslinking reaction with the polymer is prepared, and if necessary, an additive is prepared, and a mixture thereof can be used. it can. From the viewpoint of the appearance and the like of the laminated sheet, a defoaming treatment (preferably defoaming treatment under reduced pressure, also referred to as vacuum defoaming) was performed using a known defoaming device (preferably a vacuum defoaming device). An elastic layer forming composition may be used. The defoaming treatment is typically effective for a mixture of two-component compositions in which air is likely to be mixed, and can exhibit remarkable air removability when the mixed material has a high viscosity. . In addition, the elastic layer forming composition may be preliminarily cured before being supplied to the laminating step for the purpose of making the viscosity suitable.

An elastic layer (an elastic layer after the curing step; the same applies hereinafter) is a cured layer obtained by curing the composition for forming an elastic layer as described above, and is a layer having elasticity at room temperature. The elastic layer includes a viscoelastic layer. The elastic modulus (storage elastic modulus) of the elastic layer is usually 0.1 × 10 ⁵ Pa to 200 × 10 ⁵ Pa (eg, 0.5 × 10 ⁵ Pa to 100 × 10 ⁵ Pa, typically 1 × 10 ⁵ Pa to 50 × 10 ⁵ Pa). Although not particularly limited, the elastic layer has mechanical properties different from those of the first resin layer and the second resin layer (hereinafter sometimes collectively referred to as “resin layer”). The elastic layer can have, for example, an elastic modulus lower than that of the resin layer (typically about 1/100 or less of the elastic modulus of the resin layer). The storage elastic modulus is a storage elastic modulus measured at a frequency of 1 Hz and a temperature of 23 ° C., for example, a general viscoelasticity measuring device (for example, dynamic viscoelastic spectrum measurement manufactured by Rheometric Scientific, Inc.). And a model “ARES”), a sample having a thickness of 2 mm is set on a parallel plate having a diameter of 8 mm, and measurement is performed at the above frequency. What is necessary is just to set a measurement temperature range and a temperature increase rate suitably according to the model etc. of a viscoelasticity measuring apparatus.

The elastic layer may be sticky or non-sticky. For example, when the elastic layer surface is exposed from the laminated sheet or an elastic layer having an exposed surface is prepared separately, the elastic layer surface is measured by a measurement value based on a 180 ° peel test specified in JIS Z 0237: 2000. When the value is less than 0 N / 20 mm (for example, less than 0.1 N / 20 mm, typically less than 0.01 N / 20 mm), it can be evaluated as non-tacky.

The thickness of the elastic layer is usually about 10 μm to 1000 μm. From the viewpoints of curing efficiency in the curing process, function expression of the elastic layer, thickness accuracy, and the like, the thickness of the elastic layer is preferably about 20 μm to 500 μm (for example, 30 μm to 300 μm, typically 50 μm to 200 μm).

The first resin film and the second resin film (hereinafter sometimes collectively referred to as “resin film”) are films mainly composed of a resin, typically a non-porous film, This is a concept that is distinguished from so-called non-woven fabrics and woven fabrics. The resin film has a predetermined rigidity (strength), and is excellent in workability and handleability, so that it can be a suitable material that is unlikely to break down in continuous production such as a roll-to-roll method. . Moreover, it is excellent also in the supportability of the composition for elastic layer formation. For the resin film, if necessary, a filler (inorganic filler, organic filler, etc.), an anti-aging agent, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a plasticizer, a colorant (pigment, Various additives such as dyes) may be blended.

The first resin film and the second resin film are not particularly limited, but can usually have a tensile strength of about 10 MPa to 1000 MPa. From the viewpoint of handleability, productivity, etc., it is preferable to select and use a resin film having a tensile strength of about 100 MPa to 800 MPa (for example, 200 MPa to 600 MPa). The tensile strength is measured according to JIS K 7127: 1999. In addition, the tensile strength of the 1st resin film and the 2nd resin film may be the same, and may differ.

The density of the first resin film and the second resin film is 0.80 g / cm ³ to 2.0 g / cm ³ (for example, 1.00 g / cm ³ to 1.60 g / cm ³ , typically 1.20 g / cm ³ ). cm ³ to 1.50 g / cm ³ ). By using a resin film having a predetermined density in this manner, the composition for forming an elastic layer can be satisfactorily laminated. In such an embodiment, a configuration excellent in interlayer adhesion with the elastic layer is preferable. Realized. The density is measured according to ASTM D 1505. In addition, the density of the 1st resin film and the 2nd resin film may be the same, and may differ.

In addition, the first resin film and the second resin film may have low light transmittance (for example, ultraviolet transmittance) and / or moisture permeability. When such a resin film is used, a thermosetting type is preferably employed as the elastic layer forming composition, and a heating step can be preferably employed as the curing step. The resin film may have an average light transmittance at a wavelength of 400 nm or less (for example, a wavelength range of 200 nm to 400 nm), for example, 50% or less (for example, 20% or less, typically 10% or less). The light transmittance can be measured using a known spectrophotometer (for example, model “U-4100” manufactured by Hitachi High-Technologies Corporation). In addition, the said light transmittance of a 1st resin film and a 2nd resin film may be the same, and may differ.

The thicknesses of the first resin film and the second resin film can be appropriately selected according to the purpose, but generally those having a thickness of about 2 μm to 500 μm (for example, 10 μm to 200 μm) can be preferably used. Increasing the thickness tends to improve productivity, and limiting the upper limit of the thickness increases the efficiency of curing the elastic layer. In addition, the thickness of the 1st resin film and the 2nd resin film may be the same, and may differ.

In this embodiment, a primer layer is formed on the elastic layer forming surfaces of the first resin film and the second resin film before the lamination step. Thereby, the adhesiveness (throwing property) between the first resin layer, the second resin layer and the elastic layer is further improved. Such a surface treatment for improving adhesion is not limited to the formation of the primer layer, and may be a surface treatment such as corona discharge treatment or plasma treatment. As the primer layer forming material, an appropriate material may be selected based on the technical common knowledge of those skilled in the art in consideration of the elastic layer material and the resin film material. From the viewpoint of the appearance of the laminated sheet, the formation of the primer layer preferably includes a drying step, and the lamination step is preferably performed using the resin film with the primer layer after the drying step. The thickness of the primer layer is usually less than 10 μm (for example, less than 3 μm).

In the first resin film and the second resin film, an additional layer may be further laminated on the surface opposite to the elastic layer forming surface. The additional layer is not particularly limited, and a material having a desirable thickness and thickness may be appropriately selected according to the purpose. For example, a metal layer such as a copper foil described in Patent Document 1 may be laminated, or a protective layer for protecting the resin film surface may be laminated. These additional layers may be provided on at least a part of the resin film surface (surface opposite to the elastic layer forming surface) (for example, so as to cover the entire surface). The additional layer may be laminated on the resin film before lamination of the resin film and the elastic layer forming composition or after the lamination (typically after the curing step).

The first resin film and the second resin film become the first resin layer and the second resin layer, respectively, in the cured laminated sheet. Therefore, the first resin layer and the second resin layer can also be formed from the same material as the first resin film and the second resin film and have the same tensile strength, density, and thickness when viewed as a single body. . Although not particularly limited, in this embodiment, the first resin layer and the second resin layer have higher mechanical strength (for example, the above-described tensile strength and elastic modulus) than the elastic layer, and thermal expansion. The coefficient is small. As the first resin layer and the second resin layer, those having the same structure are preferably used from the viewpoint of the stability of the laminated sheet (for example, anti-curl property). In this embodiment, the first resin layer and the second resin layer are made of the same material, and have the same thickness and the same mechanical strength.

Each of the first resin layer and the second resin layer is typically non-peelable with respect to the elastic layer. Here, the two layers (the first resin layer and the elastic layer, or the second resin layer and the elastic layer) are non-peelable, in the usage mode of the laminated sheet, the two layers are used without being separated. Or at least it is used on the premise of not separating. Typically, the laminated sheet can be used in such a manner that it is evaluated as a failure when peeling occurs between the two layers. Therefore, the first resin layer and the elastic layer, and the second resin layer and the elastic layer each have a predetermined delamination strength.

Specifically, the delamination strength between the first resin layer or the second resin layer and the elastic layer both exceeds approximately 1 N / 20 mm (for example, greater than 5 N / 20 mm, typically greater than 10 N / 20 mm), or delamination. If not, the first resin layer or the second resin layer can be determined to be non-peelable with respect to the elastic layer. For the delamination strength, a strip-shaped test piece having a width of 20 mm is prepared, and using a tensile tester, the first resin layer or the second resin layer is formed from the elastic layer at a measurement temperature of 23 ° C. and a tensile speed of 50 mm / min. Is peeled into a T shape (T-type peeling), and the peeling force (interlaminar peeling strength) at that time is measured. In the measurement, for example, the elastic layer and the first resin layer are partly forcibly peeled off, and the first resin layer and the remaining layers (elastic layer and second resin layer) of the partly peeled test piece are removed. Each may be carried out by gripping with a chuck of a tensile tester. The non-peelability evaluation of the second resin layer can also be performed in the same manner as described above. As the tensile tester, a known one (for example, “Autograph” manufactured by Shimadzu Corporation) may be used. The same method as described above is adopted for the embodiments described later.

In this embodiment, since the materials and thicknesses of the elastic layer, the first resin layer, and the second resin layer are basically the same as the configuration of the laminated material described in Example 1 of Patent Document 1, here However, the material of the elastic layer (typically a cured resin layer), the first resin layer, and the second resin layer is not limited to this, for example, an acrylic resin layer, a rubber polymer layer , Polyester layer, urethane resin layer, polyether layer, polyamide layer, fluorine resin layer, epoxy resin layer, vinyl chloride resin layer, polyphenylene sulfide resin layer, polycarbonate resin layer, phenol resin layer, polyolefin layer , Styrene resin layer, polyvinyl acetate layer, ethylene-vinyl acetate resin layer, vinyl alcohol resin layer, melamine resin layer, urea resin layer, resorcinol resin layer It may be selected from the layer of resin (the layer containing a resin component as the main component). When the curing step is a heating step, it is preferable to select one having good heat resistance as the first resin layer and the second resin layer. For example, an engineering plastic is preferably used as a constituent material for the first resin layer and the second resin layer.

Next, a method for manufacturing a laminated sheet according to the second embodiment will be described. Since the manufacturing method of the laminated sheet according to the second embodiment is basically the same as the first embodiment except for the heating step, this embodiment will be described with a focus on the heating step, and other points will be described. Description is omitted.

The heating process in the second embodiment includes a preheating process in which the elastic layer forming composition is heated to a temperature T _P ° C, and a main heating in which the elastic layer forming composition is heated to a temperature T _M ° C. And a process. The preheating step and the main heating step are performed in the above order. _Here, it is preferable to satisfy _T P <T _M. Further, when the time of the preheating step is t _P and the time of the main heating step is t _M , t _P ≧ t _M (more preferably t _P > t _M , for example, t _P ≧ 2t _M ) is satisfied. preferable. By carrying out the preheating step as described above, the elastic layer forming composition is reduced in viscosity before being cured, and air and trace volatile components that can be contained in the composition are removed from the composition from the laminated sheet. Easier to escape. As a result, deterioration of interlayer adhesion and deterioration of the laminated sheet appearance are prevented.

The temperature T _P and the time t _{P in the} preheating step may be set based on the curing temperature, the curing time, etc. of the elastic layer forming composition. For example, the time t _{P of the} preheating step can be set to be smaller than the 90% curing time of the elastic layer forming composition at the temperature T _P (° C.). Further, from the viewpoint of the appearance of the laminated sheet, the temperature T _P (° C.) of the preheating step is such that the 90% curing time of the elastic layer forming composition is 2 minutes (more preferably 3 minutes, typically 5 minutes). It is preferable that the temperature (cure temperature) T _X1 (° C.) is lower. Specifically, the heating temperature T _P (° C.) in the preheating step is preferably less than 140 ° C. (for example, 130 ° C. or less, typically 60 ° C. to 90 ° C.). The time t _{P of the} preheating step is preferably about 30 seconds to 5 minutes (for example, 1 minute to 3 minutes) from the viewpoint of productivity. The temperature T _P (° C.) and the time t _P are the main thermosetting elastic layer forming compositions that are widely used (for example, a temperature of 100 ° C. to 150 ° C. and a heating time of about 1 to 3 minutes cures 90%. Therefore, the range of application is wide.

The temperatures T _M and t _M of the main heating step may be set based on the curing temperature, the curing time, etc. of the elastic layer forming composition as in the case of the heating step. For example, the time t _M of the main heating step can be set to be longer than the 90% curing time of the elastic layer forming composition at the temperature T _M (° C.) of the main heating step. Further, from the viewpoint of completing the curing step in a short time, the temperature T _M (° C.) of the main heating step is the same as the 90% curing time of the elastic layer forming composition is 5 minutes (more preferably 3 minutes, typically It is preferably higher than the temperature (curing temperature) T _X2 (° C.) at which it is 1 minute). Specifically, the heating temperature T _M (° C.) in the main heating step is preferably 100 ° C. or higher (eg, 120 ° C. to 300 ° C., typically 140 ° C. to 200 ° C.). Time t _M of the heating step, from the viewpoint of productivity, is preferably 30 seconds to 5 minutes (e.g. 1 to 3 minutes) degree. The temperature T _M (° C.) and the time t _M are generally suitable for the above-mentioned main thermosetting elastic layer forming compositions.

As in the first embodiment, the preheating step and the main heating step can be preferably performed by a configuration in which a plurality of heaters are installed along the feeding direction of the laminate. The conditions (temperature, time) of the preheating step and the main heating step can be set within a desired range by arranging a plurality of heaters and setting the individual temperatures thereof.

Hereinafter, some examples related to the present invention will be described, but the present invention is not intended to be limited to the examples shown in the examples.

<Experiment 1>
A laminated sheet sample (1) was produced by the method described in the first embodiment. Specifically, the laminated sheet sample (1) supplies the first resin film 31 to the first roll 51 and the second resin film 32 to the second roll 52 using the laminated sheet manufacturing apparatus 100 shown in FIG. Between the first resin film 31 passing over the first roll 51 and the second resin film 32 passing over the second roll 52 using a coater, the elastic layer forming composition 15 (thermosetting elasticity The first resin film 31, the elastic layer forming composition 15, and the second resin film 32 were laminated in this order (lamination step). After the laminating step, the laminated body 5 containing the elastic layer forming composition 15 is conveyed to a heater 71, and predetermined heating is performed by the heater 71 to cure the elastic layer forming composition 15. Thus, the elastic layer 10 was formed (curing step). In this way, a laminated sheet sample (1) having the same configuration as that of the first embodiment was produced.

A laminated sheet sample (2) prepared by a conventional method was prepared. In this sample (2), an elastic film to be an elastic layer is formed as a single unit using the elastic layer forming composition used in the sample (1), and then a first resin film, an elastic film, and a second resin are formed. The film was produced by laminating in this order and then heating. The material and thickness of each layer of the sample (2) are the same as those of the sample (1).

For the samples (1) and (2), the interlaminar adhesion between the first resin layer and the elastic layer, and the second resin layer and the elastic layer was evaluated by measuring the delamination strength by T-type delamination. When the target delamination strength is achieved and the resin layer and the elastic layer are firmly adhered, it is evaluated as “◯”, and the delamination strength does not reach the target value, and it is relatively easily peeled off. When it was, it was evaluated as “×”. The results are shown in Table 1.

As shown in Table 1, it was confirmed that the sample (1) was superior in interlayer adhesion to the sample (2). From this result, it can be seen that by adopting the manufacturing method disclosed herein, the interlayer adhesion of the laminated sheet can be improved by a method having excellent productivity.

<Experiment 2>
Next, the conditions of the heating process were examined. Specifically, laminated sheet samples (3) and (4) were produced in the same manner as the sample (1) except that the curing step (heating step) was changed to the conditions shown in Table 2. For comparison, sample (1) was also prepared, and the appearance of these samples (1), (3), and (4) was evaluated.

As a result of the appearance evaluation, the samples (1), (3) and (4) all had a level of appearance with no practical problem. Samples (3) and (4) were further reduced in bubble generation than sample (1) and had a better appearance. In particular, Sample (4) had a particularly excellent appearance with no generation of bubbles.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

DESCRIPTION OF SYMBOLS 1 Laminated sheet 5 Laminated body 10 Elastic layer 15 Composition for elastic layer formation 21 First resin layer 22 Second resin layer 31 First resin film 32 Second resin film 51 First roll 52 Second roll

Claims

A method for producing a laminated sheet comprising a first resin layer, a second resin layer, and an elastic layer disposed between the first resin layer and the second resin layer,
A laminating step of forming a laminate in which the elastic layer forming composition is disposed between the first resin film to be the first resin layer and the second resin film to be the second resin layer;
Subsequently to the laminating step, a curing step of curing the elastic layer forming composition to form an elastic layer;
Including
The curing step is a heating step;
The method for producing a laminated sheet, wherein the composition for forming an elastic layer before curing has fluidity in the lamination process environment and is non-volatile in the curing process environment.
The heating step includes
A preheating step of heating the elastic layer forming composition at a temperature T P ° C;
A main heating step of heating the elastic layer forming composition at a temperature T M ° C. (where T P <T M is satisfied);
The manufacturing method of Claim 1 containing this.
The manufacturing method according to claim 2, wherein the first resin layer and the second resin layer are non-peelable with respect to the elastic layer.
The laminating step includes
Supplying the first resin film to a first roll;
Supplying the second resin film to a second roll disposed so as to face the first roll; and the first resin film supplied to the first roll and the second roll supplied to the second roll. Supplying the elastic layer-forming composition between the second resin film;
The production method according to any one of claims 1 to 3, comprising