JP5307360B2 - Transfer film for firing and method for forming substrate with functional pattern - Google Patents

Description

  The present invention relates to a transfer film for forming a decorative pattern such as a conductive pattern or pattern such as a wiring circuit or an electrode on a substrate such as glass, and in particular, after transferring a laminate including a functional pattern to the substrate, The present invention relates to a transfer film for baking suitable for baking.

Conventionally, it is functional on substrates such as glass and ceramics, such as forming conductive patterns such as electric circuits on substrates, decorating ceramics, forming electrode patterns and ribs in plasma display panels, and forming antennas on glass plates for vehicles. A pattern is applied in each field.
As a method for forming a functional pattern, for example, a photolithography / etching method, a screen printing method, a sputtering method, or the like is widely adopted. However, if the substrate has a smooth surface, it can be formed directly by the above method. However, if the substrate is curved or uneven, the above method cannot be used. Therefore, a transfer method in which a functional pattern is formed in advance on a film and the functional pattern is transferred from the film to a substrate has been studied. If the transfer method is used, the functional pattern can follow the substrate regardless of the size and shape of the substrate, and can be formed on an arbitrary substrate at a low cost with excellent patternability and productivity. . For example, Patent Documents 1 to 5 describe such transfer-type films.

  Patent Document 1 discloses a ceramic decorative transfer paper in which an intermediate layer is sequentially formed by screen printing between a plurality of colored layers on a printing mount and a cover layer is provided on the top. Is provided with a transfer layer and a stress absorbing layer provided on the base film so as to be peelable, and the transfer layer contains an inorganic component containing glass frit and an organic component that can be removed by baking, and the complex elastic modulus of the stress absorbing layer. A transfer sheet for producing a plasma display panel in which the transfer layer is made smaller than the complex elastic modulus of the transfer layer is disclosed in Patent Document 4, in which a logarithmic cycle for vehicle is formed by forming a conductive pattern laminated on a transfer film on a glass plate for vehicle using a transfer method. In Patent Document 5, a dipole antenna forms a print pattern with a glass paste on a transfer film, heat-transfers the print pattern onto a substrate, and fires the transferred print pattern. The pattern forming method such as an electric circuit is disclosed, respectively. These are transfer films for baking in which a functional pattern is formed by baking after transfer to a substrate.

Japanese Patent Laid-Open No. 05-139020 JP-A-11-135209 JP 11-260250 A JP 2001-211020 A JP 2000-151080 A

The laminated body including the functional pattern of the transfer film for baking requires at least an adhesive layer for adhering the functional pattern to the substrate, and has a configuration in which several layers are laminated as necessary. The functional pattern contains inorganic powder that can be heat-sealed to develop mechanical strength after firing, and organic matter that maintains the shape before firing and is removed by firing. The adhesive layer is the functional pattern itself. It is made of an organic material that contains an adhesive component or is separately provided and decomposed and removed by firing.
When an organic substance is baked at a high temperature, thermal decomposition occurs at a temperature unique to each organic substance, and is removed as a pyrolysis gas. On the other hand, the inorganic powder in the functional pattern melts on the surface of the powder and is fused with the powder or the substrate. However, the layers other than the functional pattern are mainly composed of organic substances, and the amount of pyrolysis gas generated during firing is larger than that of the functional pattern. Therefore, thermal decomposition is caused by the influence of inorganic powder contained in the functional pattern. The firing of the functional pattern that hinders the release of gas and encapsulates bubbles is formed, or the pressure of the pyrolysis gas increases, causing the functional pattern to break or peeling from the substrate. cause. For this reason, in order to form a fired body having a good functional pattern without defects, it is important that the organic pyrolysis gas is smoothly released from the laminate including the functional pattern.

  Therefore, an object of the present invention is excellent in transferability of a laminate including a functional pattern, can smoothly discharge pyrolysis gas of organic matter by firing, and has a functional pattern free from defects such as shape and malfunction. An object of the present invention is to provide a transfer film for baking which can form a fired body on a substrate.

The present invention relates to a transfer film for firing used to form a fired body having a functional pattern by transferring and firing a laminate containing a functional pattern on the surface of a substrate. The laminate formed so as to be in contact with one surface of the film, and the laminate further includes an adhesive layer for attaching the transfer film for baking to the surface of the substrate, a release film, and an adhesive. And the functional pattern contains an inorganic powder and a first organic material that can be removed by firing, and the adhesive layer can be removed by firing, and includes the functional pattern formed between the layers. It is a transfer film for baking containing the 2nd organic substance different from a 1st organic substance.
In the transfer film for baking of the present invention, pressure is applied from above the release film to bond the functional pattern to the substrate. Thereafter, the release film is peeled off, and the functional pattern and the pressure-sensitive adhesive layer are simultaneously fired to decompose and remove excess organic matter, thereby providing the functional pattern on the substrate.

  The transfer film for baking according to the present invention further includes the thermal decomposition temperature (Tdb) of the first organic material under the baking conditions when the laminate is transferred to the surface of the substrate and baking, and the thermal decomposition of the second organic material. A transfer film for firing, characterized in that the temperature (Tda) and the fusing temperature (Tw) of the inorganic powder satisfy a relationship of Tdb <Tda <Tw.

According to one embodiment of the present invention, the laminate includes an intermediate layer formed between the functional pattern and the adhesive layer.
In one embodiment of the present invention, the thermal decomposition temperature (Tdb) of the first organic substance, the thermal decomposition temperature (Tdm) of the second organic substance, and the thermal decomposition of the organic substance contained in the adhesive layer are the firing conditions. The temperature (Tda) and the fusion temperature (Tw) of the inorganic powder satisfy the relationship Tdb <Tdm <Tda <Tw.

According to another embodiment of the present invention, the laminate includes a protective layer formed between the release film and the functional pattern for protecting the functional pattern, and the protective layer is removed by baking. A third organic material that is possible and different from the first organic material is contained.
The another embodiment is characterized in that the thermal decomposition temperature (Tdp) of the third organic substance under firing conditions and the thermal decomposition temperature (Tdb) of the first organic substance satisfy a relationship of Tdp <Tdb. To do.
According to still another embodiment of the present invention, the maximum value of the pyrolysis gas generation rate of the organic substance contained in the adhesive layer under the firing condition is 5 wt% / sec based on the initial mass of the organic substance contained in the adhesive layer. Is less than.

The present invention also relates to a method for forming a substrate with a functional pattern by transferring a laminate containing a functional pattern onto the surface of the substrate and baking the laminate, and the transfer film for baking according to the present invention is interposed through an adhesive layer. The substrate is bonded to the surface of the substrate, the release film of the transfer film for baking is peeled off, the substrate transferred with the laminate including the functional pattern is formed, and the substrate transferred by the laminate is an organic substance contained in the laminate. Is a method for forming a substrate with a functional pattern, characterized in that the substrate is fired under firing conditions that thermally decompose in the order from the surface of the substrate.
According to an embodiment of the present invention, the firing condition is such that the maximum value of the pyrolysis gas generation rate of the organic substance contained in the adhesive layer is less than 5 wt% / sec based on the initial mass of the organic substance contained in the adhesive layer. It is.

  The transfer film for baking of the present invention has a lower pyrolysis temperature of organic substances contained in the upper layer than the lower layer in the baking of the laminate including the functional pattern transferred onto the substrate, and fusion of the inorganic powder. By making the temperature higher than the pyrolysis temperature of each organic substance, the release of pyrolysis gas of the organic substance becomes good, and a functional pattern free from defects such as shape and malfunction can be formed on the substrate. Moreover, the said effect can be heightened by controlling the maximum value of the pyrolysis gas generation rate of the organic substance contained in an adhesion layer to less than 5 wt% / sec.

The present invention is described in detail below.
FIG. 1 is an enlarged cross-sectional model view illustrating the structure of a transfer film for baking that is one embodiment of the present invention. According to one embodiment of the present invention, a release film 1, a functional pattern 2 containing an inorganic powder and an organic substance that can be removed by baking on the release film 1, and an adhesive layer 3 made of an organic substance that can be removed by baking, A substrate on which a laminate containing a functional pattern is adhered after the transfer film for baking is bonded to a substrate (not shown) via the adhesive layer 3 and then the release film 1 is peeled off. By baking, the organic substance can be decomposed and removed, and a fired body having a functional pattern can be formed on the substrate. FIG. 2 shows a structure further including an intermediate layer 4 made of an organic substance that can be removed by baking between the functional pattern 2 and the adhesive layer 3, and FIG. 3 shows a structure between the functional pattern 2 and the release film 1. The enlarged cross-sectional model figure which illustrated the structure further provided with the protective layer 5 by the organic substance which can be baked and removed was shown.

Any release film may be used as long as it has a peelability with a laminate including a functional pattern, and the film base may be used as it is, but if necessary, a release layer comprising a silicone or alkyd resin on the film base. Alternatively, a configuration in which a slightly adhesive layer for re-peeling is formed may be used. Moreover, the said peeling film 1 is made into the 1st peeling film 1, the 2nd peeling film 6 is bonded together to the adhesion layer surface of the laminated body containing a functional pattern, and the laminated body containing a functional pattern between these two peeling films. It is good also as a structure which clamped. 4 shows a structure in which a laminate composed of a functional pattern 2 and an adhesive layer 3 is provided between the first release film 1 and the second release film 6, and FIG. 5 shows a functional pattern 2 and an adhesive layer. FIG. 6 is an enlarged cross-sectional model view illustrating a structure further including a protective layer 5 between the functional pattern 2 and the first release film 1. It was. In this case, it is necessary that the peeling load on the second peeling film 6 side is lighter than the peeling load on the first peeling film 1 side. The adhesive strength at the peeling interface can be adjusted depending on the type of substrate and peeling layer, the film thickness, and the like.
The base material of the release film is preferably a flexible base material in consideration of the workability at the time of transfer. For example, plastics such as polyethylene, polyimide, polyethylene terephthalate, and acrylic, and paper can be used. The thickness of the substrate is not particularly limited, and an optimum thickness may be selected from the viewpoint of the balance between the pressure and heat transferability during transfer and the flexibility of the film, preferably 25 to 250 μm, preferably 35-125 micrometers, More preferably, 50-75 micrometers is used suitably on manufacture or construction.
The release film also has a role as a support when a functional pattern and an adhesive layer constituting a laminate including a functional pattern, and further an intermediate layer and a protective layer are formed by a printing method or the like.

As a method for forming the functional pattern and each layer on the release film, a printing method such as screen printing or offset printing or a coating method such as gravure coating can be used. In the case of forming a pattern, the above printing method is preferably used. In the case where a layer is uniformly formed over a wide area, the above coating method is also preferably used in addition to the above printing method.
When forming a functional pattern or each layer by the above printing method or coating method, a coating liquid (paste) formed by dispersing or dissolving the inorganic powder or organic substance contained in the solvent is prepared and used. . In consideration of the solubility and dispersibility of inorganic powders and organic substances and the boiling point suitable for the printing process, water-based, alcohol-based, ketone-based, ester-based, ether-based, and hydrocarbon-based solvents can be used alone or in combination. Can be used. These solvents are used by appropriately adjusting the printing suitability such as viscosity and thixotropy and solid content. Most of these solvents volatilize after printing or application of the functional pattern, but the remaining part is volatilized or decomposed and removed by baking.
If necessary, additives such as an antifoaming agent and a thickening agent may be used to prevent bubbles during foaming and to adjust the viscosity. An additive that can be decomposed and removed by firing is used.

The functional pattern is mainly composed of inorganic powder that can be heat-sealed to a substrate for expressing mechanical strength after firing, inorganic powder as various functional materials according to desired functions after firing, An organic material that maintains the shape before firing and is removed by firing is contained.
As the inorganic powder that can be heat-bonded, various functional materials are supported on a substrate after firing, and materials such as glass frit can be used for the purpose of improving durability, and firing temperature and heat A glass frit having a suitable composition may be selected in consideration of a balance such as a shrinkage rate.
As the functional material, a material corresponding to a desired function after firing is appropriately selected and used. For example, powders of Au, Ag, Cu, Ni, Co, Sn, Pb, Zn, Bi, In or alloys containing these can be used for wirings and electrodes. Examples of materials used for dielectrics such as capacitor parts and high resistance parts include powders such as BaTiO, SiC, TiO ₂ , SiO ₂ , and RuO.
The organic substance is not particularly limited as long as it is a material that can be removed by firing. Examples of materials that can be easily removed by thermal decomposition by firing include resins such as acrylic, methylcellulose, nitrocellulose, ethylcellulose, vinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyethylene oxide, and polyester, either alone or in combination. Can be used. Moreover, you may add a plasticizer as an organic component in order to provide a flexibility to the coating film before baking. The plasticizer can be appropriately selected from fatty acid esters, phosphate esters, and the like.
The functional pattern may be a single pattern or a plurality of patterns, and a plurality of patterns may be laminated or individually provided. The film thickness of the functional pattern is appropriately determined according to the intended function.

The adhesive layer is not particularly limited as long as it is an organic substance that can be removed by baking, but an acrylic or rubber adhesive having adhesiveness at room temperature can be used. The adhesive layer may be formed so as to cover the entire surface of the support such as a release film, or a similar pattern may be formed on the functional pattern.
The thickness of the pressure-sensitive adhesive layer is 1 to 20 μm, preferably 2 to 10 μm. If the thickness is less than 1 μm, the adhesive strength is insufficient and transferability is lowered. If the thickness is greater than 20 μm, the amount of pyrolysis gas generated increases, so that the functional pattern is likely to be defective, and the firing is liable to occur. The thickness of the pressure-sensitive adhesive layer is preferably as thin as possible within a range where the pressure-sensitive adhesive force can be maintained.

In the present invention, an intermediate layer can be provided between the functional pattern and the adhesive layer. The intermediate layer plays a role of a barrier property to prevent penetration of the solvent or organic substance contained in the pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer into the functional pattern.
The intermediate layer is not particularly limited as long as it is an organic material that can be removed by firing, but can be selected from the same organic materials used for the functional pattern. In particular, a polymer resin having a glass transition temperature of 50 ° C. or higher is preferable because of its high barrier effect.
The intermediate layer may be formed so as to cover the entire support such as a release film, or a similar pattern may be formed on the functional pattern. If the film thickness of the intermediate layer is 0.5 μm or more, there is a barrier effect, but preferably 1 μm or more is required. When the intermediate layer is thick, the amount of pyrolysis gas generated increases, so that defects are easily generated in the functional pattern, resulting in poor firing. Therefore, the film thickness of the intermediate layer is 10 μm or less, preferably 5 μm or less, and it is preferable to make it as thin as possible.

The protective layer plays a role of protecting the functional pattern before firing transferred to the substrate from adhesion or scratches of foreign matters. In addition, since the functional pattern contains a small proportion of organic matter, the film quality before firing tends to be hard and brittle. Therefore, when the transfer film is bent, the functional pattern is likely to crack. For this reason, the protective layer also plays a role of preventing cracks when the film is bent. The protective layer is not particularly limited as long as it is an organic substance that can be removed by firing, but can be selected from the same organic substances used for the functional pattern.
The protective layer may be formed so as to cover the functional pattern, or may be formed in the same pattern shape as the functional pattern. The thickness of the protective layer is preferably 0.1 to 2 μm.

  According to one embodiment of the present invention, the functional pattern is sandwiched between the protective layer and the intermediate layer, so that the flexibility is improved, and the workability of construction such as bonding to the substrate and transfer is enhanced. Further, since the protective layer and the intermediate layer cover the adhesive layer, the adhesive layer is not exposed after transfer, and foreign matter adhesion due to the adhesiveness of the adhesive layer can be prevented. Furthermore, even for functional patterns such as fine lines and dots, by forming a protective layer, intermediate layer, and adhesive layer on the entire support surface, the contact area with the substrate can be reduced without depending on the pattern shape or size of the functional pattern. Can be widened and the adhesive strength is sufficiently maintained. In addition, there is an advantage that a plurality of functional patterns can be transferred at a time and the positional accuracy is improved.

Next, it will be described that the laminate including the functional pattern transferred to the surface of the substrate using the baking transfer film of the present invention is excellent in baking properties.
The functional pattern needs to be patterned after the organic matter is thermally decomposed and removed by firing, and then the inorganic powder is fused. When the organic matter is exposed to high temperature, thermal decomposition occurs at a temperature unique to each organic matter and is removed as pyrolysis gas. The inorganic powder such as glass frit and functional material contained in the functional pattern is melted, and fusion between the melted powders or fusion between the melted powder and the substrate occurs. (At this time, the functional material is held in a melt such as a glass frit and thus does not necessarily need to be melted.) The laminate including the functional pattern to be fired is formed from the upper layer to the protective layer, the functional pattern, and the intermediate layer. In firing the film laminated on the substrate in the order of the layer and the adhesive layer, lowering the pyrolysis temperature of the organic material in the upper layer relative to the lower layer relative to the substrate facilitates release of the pyrolysis gas in the lower layer. As a result, it is possible to form a functional pattern on the substrate that is free of defects such as bubble defects in the functional pattern, shape defects such as peeling from the substrate, and associated functional failures.
Therefore, the transfer film for firing of the present invention has an organic decomposition thermal decomposition temperature (Tda) of the adhesive layer, an organic decomposition thermal decomposition temperature (Tdb) of the functional pattern layer, and an inorganic powder fusing temperature (Tw) of Tdb. It is necessary to satisfy the relationship <Tda <Tw. Further, when an intermediate layer is provided between the functional pattern and the adhesive layer, the thermal decomposition temperature (Tdm) of the organic substance in the intermediate layer needs to satisfy the relationship of Tdb <Tdm <Tda <Tw. When the inorganic powder is composed of a plurality of types of powder, the fusion temperature (Tw) of the inorganic powder of the above relational expression is the lowest fusion temperature.

In particular, the pressure-sensitive adhesive layer is located at the position in contact with the substrate, that is, the lowermost layer, and the film thickness is relatively thick. Moreover, if the temperature increase rate at the time of baking is high, the amount of pyrolysis gas per unit time will increase and the decomposition temperature will also shift to a high temperature side. Therefore, in order to obtain a good fired film, the maximum pyrolysis gas rate of the adhesive layer must be 5 wt% / sec or less, preferably 3 wt% / sec or less, based on the initial weight of the organic substance contained in the adhesive layer. There is.
Here, the thermal decomposition temperature was defined as the temperature at which the differential value of the weight change curve was maximized when the temperature was raised with the same temperature raising program as that used in the firing furnace in thermogravimetry. The pyrolysis gas generation rate is expressed in terms of the decomposition weight rate per unit time of the temperature at which the differential value of the weight change curve is maximum based on the initial weight of the organic matter to be decomposed, and the unit is expressed in wt% / sec. It was. Further, the heat fusion temperature of the inorganic powder was determined from the observation result of the film surface when fired by the above temperature raising program.

When a protective layer is provided on the side opposite to the adhesive layer of the functional pattern, the thermal decomposition temperature (Tdp) of the organic substance contained in the protective layer is the thermal decomposition temperature (Tdb) of the organic substance contained in the functional pattern. The following is necessary (Tdp <Tdb).
Since the protective layer is formed in the upper layer of the functional pattern and becomes the uppermost layer of the laminate, a good fired film can be formed by satisfying the relationship of Tdp <Tdb. Even in the relationship of Tdp> Tdm, if the film thickness is in the range of 0.1 to 2 μm, the pyrolysis gas in the lower layer can pass through the partially decomposed protective layer and release gas. However, when the protective layer is thicker than 2 μm, defective firing is likely to occur due to the release of pyrolysis gas in the lower layer.

Specific examples of the present invention will be described below. The present invention is not limited to these examples.
Example 1
(Preparation of transfer film for firing)
The transfer film for baking was produced in the following procedures.
As the release film, a PET film “A70” provided with a silicone release layer (manufactured by Teijin DuPont Films, film size 20 cm × 30 cm, thickness 50 μm) was prepared.
A conductive paste was prepared as a functional pattern coating solution using a three-roll mill based on the composition shown in Table 1.
Next, if necessary, a drying process using an oven, a hot air drying furnace, an IR dryer or the like is performed. For example, drying at 120 ° C. for 10 minutes can be performed in an oven.
An adhesive layer paste was prepared by replacing the solvent of the acrylic adhesive “SK1451” (manufactured by Soken Chemical Industry Co., Ltd.) with Solvesso 150 as the adhesive layer coating solution.
On the release layer of the release film, the conductive paste was printed to a size of 2 cm × 5 cm and a film thickness of 15 μm using a screen printer to form a functional pattern.
The adhesive layer paste was printed to a size of 2 cm × 5 cm and a film thickness of 10 μm using a screen printer so as to overlap the functional pattern, thereby forming an adhesive layer.

(Production of substrate with functional pattern)
A substrate with a functional pattern was prepared by the following procedure.
A glass plate (size 30 cm × 30 cm) manufactured by the float process was prepared as a substrate.
On the surface of this glass plate, the transfer film for baking immediately after production was bonded to the release film with a pressure of 0.5 kg / cm using a roller with the adhesive layer facing each other. Thereafter, the release film was peeled off to produce a glass plate onto which the laminate including the functional pattern was transferred.
And this glass plate was baked using the baking furnace. The firing condition was that the temperature was raised from room temperature to 650 ° C. at a rate of temperature rise of 20 ° C./min, and the temperature was maintained for 30 minutes, and then cooled to 100 ° C. or less by standing in the furnace.
And the cooled glass plate with a functional pattern was taken out from the baking furnace.

(Measurement of thermal characteristics)
The thermal characteristics of organic and inorganic powders contained in each layer of the laminate including the functional pattern are based on JISK7129 (Thermogravimetric method for plastics). (Manufactured by Science Co., Ltd.), and the temperature was raised from the room temperature to 650 ° C. in the atmosphere (same as the above-mentioned firing conditions) at a heating rate of 20 ° C./min. Each thermal characteristic is as follows. The thermal decomposition temperature (Tdb) of the organic substance contained in the conductive paste is 335 ° C., the fusing temperature (Tw) of the glass frit is 490 ° C. The thermal decomposition temperature (Tda) of the adhesive layer was 414 ° C., and the pyrolysis gas generation rate of the adhesive layer was 0.47 wt% / sec.

(Example 2)
The transfer for firing was carried out in the same manner as in Example 1 except that an acrylic pressure-sensitive adhesive “SK1309” (manufactured by Soken Chemical Industry Co., Ltd.) was used as the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, and the film thickness of the pressure-sensitive adhesive layer was 5 μm. A film was prepared.
A glass plate with a functional pattern was produced in the same manner as in Example 1 except that the firing rate was 500 ° C./min and the maintenance time at 650 ° C. was 5 minutes.
The thermal characteristics measured under the same temperature rise conditions as the firing conditions are as follows: the decomposition temperature (Tdb) of the organic matter contained in the conductive paste is 355 ° C., the fusing temperature (Tw) of the glass frit is 510 ° C. The thermal decomposition temperature (Tda) was 481 ° C., and the thermal decomposition gas generation rate of the adhesive layer was 4.19 wt% / sec.

(Comparative Example 1)
A transfer film for baking was produced in the same manner as in Example 1 except that an acrylic adhesive “SP-205” (manufactured by Toyo Ink Co., Ltd.) was used as the adhesive used for the adhesive layer.
A glass plate with a functional pattern was produced in the same manner as in Example 1.
The thermal characteristics measured under the same temperature rise conditions as the firing conditions are as follows: the thermal decomposition temperature (Tdb) of the organic substance contained in the conductive paste is 335 ° C., and the fusing temperature (Tw) of the glass frit is 490 ° C. The pyrolysis temperature (Tda) was 309 ° C., and the pyrolysis gas generation rate of the adhesive layer was 0.31 wt% / sec.

(Comparative Example 2)
A transfer film for baking was produced in the same manner as in Example 1 except that the thickness of the adhesive layer was 5 μm.
A glass plate with a functional pattern was produced in the same manner as in Example 1 except that the firing conditions were the same as in Example 2.
The thermal characteristics measured under the same temperature rise conditions as the firing conditions are as follows: the decomposition temperature (Tdb) of the organic matter contained in the conductive paste is 355 ° C., the fusing temperature (Tw) of the glass frit is 510 ° C. The thermal decomposition temperature (Tda) was 485 ° C., and the thermal decomposition gas generation rate of the adhesive layer was 5.01 wt% / sec.

(Evaluation)
Table 2 shows the thickness of the adhesive layer, the heating rate of firing, the thermal characteristics of the functional pattern and the adhesive layer, and the evaluation of the fired body of the functional pattern in Examples 1 and 2 and Comparative Examples 1 and 2. . In the evaluation, “Good” indicates that the fired body of the functional pattern has no defect and “Good” indicates that there is a defect and “×” indicates that there is a defect.
The fired bodies of the functional patterns in Example 1 and Example 2 were free from defects and good evaluation was obtained. In contrast, partial firing unevenness and poor adhesion occurred in the fired body of the functional pattern in Comparative Example 1, and damage such as cracks and peeling occurred in the fired body of the functional pattern in Comparative Example 2. As a result, good evaluation could not be obtained.

(Contrast)
Comparison between Example 1 and Example 2 is performed.
The functional patterns and thermal characteristics of the adhesive layer in Example 1 and Example 2 satisfied the relationship of Tdb <Tda <Tw. In particular, in Example 2, the heating rate of baking was 25 times faster than that of Example 1, and thus the pyrolysis gas generation rate of the adhesive layer was about 8.9 times faster than that of Example 1. Regardless, a fired body having a good functional pattern similar to that of Example 1 was obtained.
The organic matter contained in the upper functional pattern is thermally decomposed and removed the fastest, and the lower adhesive layer is pyrolyzed and removed before the glass frit (inorganic powder) contained in the functional pattern is fused. Therefore, it is considered that no defects occurred in the fired body of the functional pattern.

Comparison between Examples 1 and 2 and Comparative Example 1 is performed.
In Example 1 and Comparative Example 1, the thickness of the pressure-sensitive adhesive layer, the thickness of the functional pattern, and the heating rate of baking were the same, but the type of pressure-sensitive adhesive used in the pressure-sensitive adhesive layer was different, so the heat of the pressure-sensitive adhesive layer The decomposition temperature (Tda) and the pyrolysis gas generation rate of the adhesive layer were different. In Example 2 and Comparative Example 1, since the kind of the adhesive used for the adhesive layer, the thickness of the adhesive layer, and the heating rate of baking differ, the fusing temperature (Tw) of the glass frit contained in the functional pattern is different. ), The thermal decomposition temperature (Tda) of the adhesive layer and the pyrolysis gas generation rate of the adhesive layer were different.
In Comparative Example 1, regarding the thermal characteristics of the functional pattern and the adhesive layer, the thermal decomposition temperature (Tda) of the adhesive layer was the lowest and did not satisfy the relationship of Tdb <Tda <Tw. In Comparative Example 1, the pyrolysis gas generation rate of the adhesive layer is about 0.66 times that of Example 1, which is a slower rate. Further, compared to Example 2, the pyrolysis gas generation rate of the adhesive layer is about A fired body having a good functional pattern could not be obtained even though the speed was 0.074 times and the speed was considerably low.

In Comparative Example 1, the lower adhesive layer is thermally decomposed faster than the organic matter contained in the upper functional pattern is thermally decomposed and removed, and the generated pyrolytic gas has changed the upper functional pattern in some places. It is considered that partial firing unevenness and poor adhesion occurred in the fired body of the functional pattern.
From these contrasts, it is understood that the relationship of Tdb <Tda <Tw needs to be satisfied in order to obtain a good functional pattern.

Comparison between Examples 1 and 2 and Comparative Example 2 is performed.
In Example 1 and Comparative Example 2, the type of pressure-sensitive adhesive used in the pressure-sensitive adhesive layer and the thickness of the functional pattern were the same, but the functional pattern was different because the film thickness of the pressure-sensitive adhesive layer and the heating rate of baking were different. The fusing temperature (Tw) of the glass frit contained in the glass, the thermal decomposition temperature (Tda) of the adhesive layer, and the pyrolysis gas generation rate of the adhesive layer were different. In Example 2 and Comparative Example 2, the thickness of the pressure-sensitive adhesive layer, the thickness of the functional pattern, and the rate of temperature increase of firing were the same, but the type of pressure-sensitive adhesive used in the pressure-sensitive adhesive layer was different, so the heat of the pressure-sensitive adhesive layer The decomposition temperature (Tda) and the pyrolysis gas generation rate of the adhesive layer were different. But the difference was small.
In Comparative Example 2, the thermal characteristics of the functional pattern and the adhesive layer satisfy the relationship of Tdb <Tda <Tw, and the film thickness of the adhesive layer was half that of Example 1, but a good functional pattern. No fired body was obtained. At this time, the pyrolysis gas generation rate of the adhesive layer with respect to Example 1 of Comparative Example 2 was about 10.7 times, which was a high rate, but the pyrolysis gas generation rate of the adhesive layer with respect to Example 1 of Example 2 was high. Compared to about 8.9 times, it was not so fast.

In Comparative Example 2, the thermal decomposition of the organic substance contained in the upper functional pattern and the thermal decomposition of the lower adhesive layer proceed almost simultaneously, and the generation rate of the pyrolysis gas in the adhesive layer exceeded the limit. It is considered that the pyrolysis gas of the layer was released through the functional pattern of the upper layer in some places, and the fired body of the functional pattern was damaged such as cracking or peeling. The reason why no damage was observed in the functional pattern of Example 2 fired at the same temperature rising rate is considered to be because the pyrolysis gas generation rate of the adhesive layer did not exceed the limit.
Based on these comparisons, when firing at a high temperature rise rate, in order to obtain a fired body with a good functional pattern, in addition to satisfying the relationship of Tdb <Tda <Tw, the pyrolysis gas generation rate of the adhesive layer Is also an important condition.

(Example 3)
(Preparation of transfer film for firing)
In the following procedure, the transfer film for baking which added the intermediate | middle layer and the 2nd peeling film to the structure of the transfer film for baking of Example 1 was produced.
The same PET film as in Example 1 was prepared as the first release film.
A PET film “A31” (manufactured by Teijin DuPont Films, film size 20 cm × 30 cm, thickness 25 μm) provided with a silicone release layer as a second release film was prepared.
A conductive paste similar to that in Example 1 was prepared as a functional pattern coating solution.
A polyvinyl acetal resin “KW1” (manufactured by Sekisui Chemical Co., Ltd.) was prepared as an intermediate layer coating solution, and used as an intermediate layer paste.
The same acrylic pressure-sensitive adhesive “SK1309” as in Example 2 was prepared as a coating solution for the pressure-sensitive adhesive layer, and used as a pressure-sensitive adhesive layer paste.

On the release layer of the first release film, the conductive paste was printed to a size of 2 cm × 5 cm and a film thickness of 15 μm using a screen printer to form a functional pattern.
The intermediate layer paste was applied using a Mayer bar so as to cover the functional pattern so as to have a size of 5 cm × 10 cm and a film thickness of 2 μm.
Subsequently, drying was performed in an oven at 120 ° C. for 10 minutes.
The adhesive layer paste was applied to a size of 5 cm × 10 cm and a film thickness of 1 μm using a Mayer bar so as to overlap the intermediate layer, thereby forming an adhesive layer.
A second release film was bonded from the release layer side so as to cover the adhesive layer.
In this way, two transfer films for baking were produced. These baking transfer films were stored in a temperature environment of 30 ° C.

(Production of substrate with functional pattern)
Using the two transfer films for baking stored in the temperature environment, a substrate with a functional pattern was produced by the following procedure after 1 hour and 1 week, respectively.
A glass plate (size 30 cm × 30 cm) manufactured by the float process was prepared as a substrate.
The 2nd peeling film was peeled from the transfer film for baking.
The transfer film for baking was bonded to the surface of the glass plate with a pressure of 0.5 kg / cm from above the first release film using a roller with the adhesive layer facing each other. Then, the 1st peeling film was peeled and the glass plate in which the laminated body containing a functional pattern was transcribe | transferred was produced.
And this glass plate was baked using the baking furnace, and the glass plate with a functional pattern was produced. The firing conditions were the same as in Example 1.

(Measurement of thermal characteristics)
The thermal characteristics of the organic matter and inorganic powder contained in each layer of the laminate including the functional pattern were measured under the same temperature rising conditions as the firing conditions. The thermal characteristics are as follows: the thermal decomposition temperature (Tdb) of the organic substance contained in the conductive paste is 335 ° C., the fusing temperature (Tw) of the glass frit is 490 ° C., and the thermal decomposition temperature (Tda) of the adhesive layer is 401. The pyrolysis gas generation rate was 0.51 wt% / sec, and the pyrolysis temperature (Tdm) of the organic substance contained in the intermediate layer (hereinafter simply referred to as the intermediate layer) was 370 ° C.

(Comparative Example 3)
In the same manner as in Example 3, two baking transfer films were produced in which the intermediate layer was omitted from the structure of the baking transfer film of Example 3.
In the same manner as in Example 3, two glass plates with a functional pattern were prepared using two transfer films for baking with different storage periods.

(Evaluation)
In Example 3 and Comparative Example 3, the thickness of the pressure-sensitive adhesive layer was set to 1 μm where the adhesive force was intentionally unstable in order to confirm the effect of the intermediate layer. Since the adhesive layer was covered with the second release film until just before transfer, adhesion of dust or the like to the adhesive layer could be prevented.
Table 3 shows the state of transfer of the laminate including the functional pattern of the transfer film for firing in Example 3 and Comparative Example 3 to the glass plate (hereinafter referred to as transferability) and the state of the fired body of the functional pattern (hereinafter referred to as “transferred”). , Called fireability). As for evaluation, regarding transferability, the laminate was able to adhere well without lifting from the glass plate with `` ○ '', the laminate partially lifted from the glass plate with `` X '', “−” Indicates that the laminated body could not be transferred to the glass plate, and regarding the baking property, “good” indicates that the fired body of the functional pattern has no defects and “good” indicates that there is a defect and indicates that there are defects. A symbol “-” indicates that firing could not be performed.
In Example 3, the transferability and baking property were good when the storage period was 1 hour, and the transferability and baking property were good when the storage period was 1 week. On the other hand, in the case of the storage period of 1 hour in Comparative Example 3, both the transferability and the baking property are poor, and in the case of the storage period of 1 week, the laminate cannot be transferred to the glass plate, and baking is performed. could not.

(Contrast)
Comparison between Example 3 and Comparative Example 3 is performed.
The only difference between the firing transfer film in Example 3 and the firing transfer film in Comparative Example 3 is the presence or absence of an intermediate layer. When there is no intermediate layer, it is considered that the pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer was moved to the functional pattern and the pressure-sensitive adhesive force was weakened. When the intermediate layer is present, it is considered that the adhesive force is maintained by preventing the movement of the adhesive.
From this comparison, it was confirmed that the film thickness of the adhesive layer can be reduced by forming an intermediate layer capable of preventing the movement of the adhesive between the adhesive layer and the functional pattern.

Example 4
A transfer film for baking was produced in the same manner as in Example 3 except that hydroxycellulose-based resin “SP200” (manufactured by Daicel Chemical Industries, Ltd.) was used as the intermediate layer and the film thickness was 2 μm.
A glass with a functional pattern using the transfer film for firing in the same manner as in Example 3 except that the heating rate was 500 ° C./min and the maintenance time at 650 ° C. was 5 minutes. A plate was made.
The thermal characteristics measured under the same temperature rise conditions as the firing conditions are as follows: the thermal decomposition temperature (Tdb) of the organic substance contained in the conductive paste is 355 ° C., and the fusing temperature (Tw) of the glass frit is 510 ° C. The thermal decomposition temperature (Tda) was 481 ° C., the pyrolysis gas generation rate was 4.19 wt% / sec, and the thermal decomposition temperature (Tdm) of the intermediate layer was 370 ° C.

(Comparative Example 4)
A transfer film for baking was produced in the same manner as in Example 3 except that carboxymethyl cellulose resin “CMC-1240” (manufactured by Daicel Chemical Industries, Ltd.) was used as the intermediate layer with a film thickness of 2 μm.
Transfer-formed on a glass plate.
By the method similar to Example 3, the glass plate with a functional pattern was produced using the said transfer film for baking.
The thermal characteristics measured under the same heating conditions as the firing conditions are as follows: the decomposition temperature (Tdb) of the organic matter in the conductive paste is 419 ° C., the fusing temperature (Tw) of the glass frit is 510 ° C. The pyrolysis temperature (Tda) was 414 ° C., the pyrolysis gas generation rate was 0.47 wt% / sec, and the pyrolysis temperature (Tdm) of the organic substance in the intermediate layer was 290 ° C.

(Comparative Example 5)
A transfer film for baking was produced in the same manner as in Example 3 except that an acrylic resin “BR50” (manufactured by Mitsubishi Rayon Co., Ltd.) was used as the intermediate layer and the film was formed with a film thickness of 2 μm.
A glass plate with a functional pattern was produced using the transfer film for firing in the same manner as in Example 3 except that the firing conditions were the same as in Example 4.
The thermal characteristics measured under the same heating conditions as the firing conditions are as follows: the thermal decomposition temperature (Tdb) of the organic matter in the conductive paste is 355 ° C., the fusing temperature (Tw) of the glass frit is 510 ° C., and the heat of the adhesive layer The decomposition temperature (Tda) was 481 ° C., the pyrolysis gas generation rate was 4.19 wt% / sec, and the thermal decomposition temperature (Tdm) of the intermediate layer was 492 ° C.

(Evaluation)
Table 4 shows the heating rate of firing in Examples 3 and 4 and Comparative Examples 4 and 5, the thermal characteristics of each layer, and the evaluation of the fired body of the functional pattern. In the evaluation, “Good” indicates that the fired body of the functional pattern has no defect and “Good” indicates that there is a defect and “×” indicates that there is a defect.
The fired bodies of the functional patterns in Example 3 and Example 4 were free from defects and good evaluation was obtained. In contrast, the fired body of the functional pattern in Comparative Example 4 was damaged, and the fired body of the functional pattern in Comparative Example 5 was poorly adhered. It was.

(Contrast)
Comparison between Example 3 and Example 4 is performed.
The thermal characteristics of each layer in Example 3 and Example 4 satisfied the relationship of Tdb <Tdm <Tda <Tw. In particular, in Example 2, the heating rate of baking was 25 times faster than that of Example 3, and the pyrolysis gas generation rate of the adhesive layer was about 8.2 times faster than that of Example 3. Regardless, a fired body having a good functional pattern similar to that of Example 3 was obtained. This result was the same as the relationship between Example 1 and Example 2 without the intermediate layer.

Comparison between Example 3 and Comparative Example 4 is performed.
In Example 3 and Comparative Example 4, the resin used as the intermediate film was different. As a result, in Comparative Example 4, the thermal decomposition temperature (Tdm) of the interlayer film was lower than the thermal decomposition temperature (Tdb) of the organic substance contained in the functional pattern. Therefore, in Comparative Example 5, the lower intermediate layer is thermally decomposed faster than the organic substance contained in the upper functional pattern is thermally decomposed and removed, and the generated pyrolysis gas is generated at various locations in the upper layer. It is considered that the functional pattern fired body was damaged by being released through the pattern.

Comparison between Example 4 and Comparative Example 5 is performed.
In Example 4 and Comparative Example 5, the resin used as the intermediate film was different. As a result, in Comparative Example 5, the thermal decomposition temperature (Tdm) of the interlayer film was higher than the thermal decomposition temperature (Tda) of the adhesive layer. Therefore, in Comparative Example 5, the lower adhesive layer is thermally decomposed faster than the upper intermediate film is thermally decomposed and removed, and the generated pyrolysis gas pushes up the upper intermediate layer in some places, It is considered that an adhesion failure occurred in the fired product of the functional pattern by pushing up the upper functional pattern.

  Even if the number of layers of the laminate including the functional pattern is increased by the above comparison, the organic matter contained in each layer is thermally decomposed and removed sequentially from the upper layer, and the inorganic powder contained in the functional pattern Before bonding, the lower layer than the functional pattern is thermally decomposed and removed, that is, by satisfying the relationship of Tdb <Tdm <Tda <Tw, it is possible to obtain a fired body having a functional pattern without defects. It could be confirmed.

(Example 5)
(Preparation of transfer film for firing)
In the following procedure, the transfer film for baking which added the intermediate | middle layer, the protective layer, and the 2nd peeling film to the structure of the transfer film for baking of Example 1 was produced.
A PET film “SRL-0754” (manufactured by Lintec Corporation, film size 20 cm × 30 cm, thickness 75 μm) provided with a slightly adhesive layer as a first release film was prepared.
A PET film “A31” (manufactured by Teijin DuPont Films, film size 20 cm × 30 cm, thickness 38 μm) provided with a silicone release layer as a second release film was prepared.
Polyethylene oxide resin “PEO-8Z” (manufactured by Sumitomo Seika Co., Ltd.) was prepared as a coating solution for the protective layer, and used as a protective layer paste.
A conductive paste similar to that in Example 1 was prepared as a functional pattern coating solution.
The same polyvinyl acetal resin “KW1” as that of Example 3 was prepared as an intermediate layer coating solution to obtain an intermediate layer paste.
The same acrylic pressure-sensitive adhesive “SK1309” as in Example 3 was prepared as a coating solution for the pressure-sensitive adhesive layer, and used as a pressure-sensitive adhesive layer paste.

On the release layer of the second release film, the adhesive layer paste was applied to a size of 5 cm × 10 cm and a film thickness of 5 μm using a Mayer bar to form a functional pattern.
The intermediate layer paste was applied using an applicator so as to cover the adhesive layer so as to have a size of 6 cm × 12 cm and a film thickness of 2 μm.
On the intermediate layer, the conductive paste was printed using screen printing so as to have a size of 0.3 mm × 5 cm and a film thickness of 15 μm, thereby forming a functional pattern.
The protective layer paste was applied using an applicator so as to cover the functional pattern so as to have a size of 6 cm × 12 cm and a thickness of 3 μm, thereby forming a protective layer.
The 1st peeling film was bonded together from the slightly adhesion layer side so that a protective layer might be covered.

(Production of substrate with functional pattern)
A substrate with a functional pattern was prepared by the following procedure.
A glass plate (size 30 cm × 30 cm) manufactured by the float process was prepared as a substrate.
The 2nd peeling film was peeled from the said transfer film for baking.
The transfer film for baking was bonded to the surface of the glass plate with a pressure of 0.5 kg / cm from above the first release film using a roller while the adhesive layer was faced and bent with a curvature of Φ5 mm. . Then, the 1st peeling film was peeled and the glass plate in which the laminated body containing a functional pattern was transcribe | transferred was produced.
And this glass plate was baked using the baking furnace, and the glass plate with a functional pattern was produced. The firing conditions were the same as in Example 1.

(Measurement of thermal characteristics)
The thermal characteristics of the organic matter and inorganic powder contained in each layer of the laminate including the functional pattern were measured under the same temperature rising conditions as the firing conditions. The thermal characteristics are as follows: the thermal decomposition temperature (Tdb) of the organic substance contained in the conductive paste is 335 ° C., the fusing temperature (Tw) of the glass frit is 490 ° C., and the thermal decomposition temperature (Tda) of the adhesive layer is 401. The pyrolysis gas generation rate is 0.51 wt% / sec, the pyrolysis temperature (Tdm) of the intermediate layer is 370 ° C., and the organic substance contained in the protective layer (hereinafter simply referred to as the protective layer) is thermally decomposed. The temperature (Tdp) was 305 ° C.

(Comparative Example 6)
A transfer film for baking was produced in the same manner as in Example 5 except that the same polyacetal resin “KW1” as that of the intermediate layer paste was used as the protective layer paste and the film was applied with an applicator to a thickness of 3 μm.
By the method similar to Example 5, the glass plate with a functional pattern was produced using the said transfer film for baking.
The thermal characteristics measured under the same heating conditions as the firing conditions are as follows: the thermal decomposition temperature (Tdb) of the organic matter in the conductive paste is 335 ° C., the fusing temperature (Tw) of the glass frit is 490 ° C. The decomposition temperature (Tda) was 401 ° C., the pyrolysis gas generation rate was 0.51 wt% / sec, the intermediate layer thermal decomposition temperature (Tdm) was 370 ° C., and the protective layer thermal decomposition temperature (Tdp) was 370 ° C. .

(Evaluation)
Table 5 shows measured values of thermal characteristics of each layer and evaluation of transferability and combustibility in Example 5 and Comparative Example 6. As for evaluation, regarding transferability, the laminate was able to adhere well without lifting from the glass plate with `` ○ '', the laminate partially lifted from the glass plate with `` X '', “−” Indicates that the laminated body could not be transferred to the glass plate, and regarding the baking property, “good” indicates that the fired body of the functional pattern has no defects and “good” indicates that there is a defect and indicates that there are defects. A symbol “-” indicates that firing could not be performed.

In Example 5 and Comparative Example 6, when the laminate including the functional pattern was transferred to the substrate, the transfer film for baking was bonded to the substrate while bending with a curvature of Φ5 mm, but no cracks occurred. Good transferability was obtained. This is considered to be achieved by the protective layer protecting the brittle functional pattern before firing.
In Example 5, good combustibility was obtained for the fired body having a functional pattern without causing cracks. However, in Comparative Example 6, uneven firing and poor adhesion occurred partially in the fired body of the functional pattern, and good combustibility was not obtained.
In Comparative Example 6, the thermal decomposition temperature (Tdp) of the uppermost protective layer was higher than the thermal decomposition temperature (Tdb) of the organic substance contained in the lower functional pattern. Therefore, it is considered that the release of pyrolysis gas of organic substances contained in the functional pattern was hindered by the protective layer, and good combustibility was not obtained.

  Even if the number of layers of the laminate including the functional pattern is increased by the above comparison, the organic matter contained in each layer is thermally decomposed and removed sequentially from the upper layer, and the inorganic powder contained in the functional pattern By fusing and removing the lower layer than the functional pattern before fusing, that is, satisfying the relationship of Tdp <Tdb <Tdm <Tda <Tw, a sintered body having a functional pattern having no defect can be obtained. I was able to confirm.

It is an expanded sectional model diagram which illustrates the transfer film for baking of one Example of this invention. It is an expanded sectional model diagram which illustrates the transfer film for baking of another one Example of this invention. It is an expanded sectional model diagram which illustrates the transfer film for baking of another one Example of this invention. It is an expanded sectional model diagram which illustrates the transfer film for baking of other one Example of this invention. It is an expanded sectional model diagram which illustrates the transfer film for baking of other one Example of this invention. It is an expanded sectional model diagram which illustrates the transfer film for baking of other one Example of this invention.

Explanation of symbols

1 Release film (first release film)
2 Functional pattern 3 Adhesive layer 4 Intermediate layer 5 Protective layer 6 Second release film

Claims (2)

In a transfer film for firing used to form a fired body of a functional pattern by transferring and firing a laminate containing a functional pattern on the surface of a substrate,
The transfer film for baking includes a release film, and the laminate formed to be in contact with one surface of the release film,
The laminate further includes an adhesive layer for adhering the transfer film for baking to the surface of the substrate, and a functional pattern formed between the release film and the adhesive layer,
The functional pattern contains an inorganic powder and a first organic material that can be removed by firing,
The adhesive layer has a second organic material that is adhesive at room temperature, can be removed by firing, and is different from the first organic material,
The laminate includes an intermediate layer formed between the functional pattern and the adhesive layer,
The laminate includes a protective layer formed between the release film and the functional pattern for protecting the functional pattern,
The protective layer contains a third organic material that can be removed by firing and is different from the first organic material,
The thermal decomposition temperature (Tdb) of the first organic material, the thermal decomposition temperature (Tda) of the second organic material, and the inorganic powder under the firing conditions when the laminate is transferred to the surface of the substrate and fired Of the organic material contained in the intermediate layer, and the thermal decomposition temperature (Tdp) of the third organic material , Tdp < Tdb < Tdm < Tda <Tw The transfer film for baking characterized by satisfying the above relationship. In a method for forming a substrate with a functional pattern by transferring and firing a laminate including a functional pattern on the surface of the substrate,
A laminate comprising a functional pattern, wherein the firing transfer film according to claim 1 is attached to the surface of the substrate via the adhesive layer, and the release film of the firing transfer film is peeled off. Forming a body transferred body,
A method for forming a substrate with a functional pattern, wherein the substrate transferred by the laminate is fired under firing conditions in which organic substances contained in the laminate are pyrolyzed in order from the surface of the substrate.

Images