JP2023023668A - Film, film with release film, diaphragm, laminate, molded product and acoustic transducer - Google Patents

Abstract

To provide a film that can prevent delamination of multilayer films when the release film is peeled off before molding, while maintaining high shape retention before molding, and high formability and mold-following property during molding.SOLUTION: A film of the present invention is a film which has a curable silicone layer (A) with another silicone layer (B) on at least one side and the following (a) viscoelastic properties, and in which the arithmetic mean height (Sa) of at least one side between the layers of the silicone layer (A) and the silicone layer (B) is 500 to 4000 nm. (a) The storage modulus E'(10 Hz) at a measurement temperature of 20°C and a frequency of 10 Hz is 0.1 MPa to 500 MPa.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to films used to obtain molded articles such as acoustic members, films with release films, and diaphragms, laminates, molded articles, and acoustic transducers obtained from these films.

For example, with the spread of small electronic devices such as smartphones, PDAs, notebook computers, DVDs, liquid crystal televisions, digital cameras, and portable music devices, small speakers (usually called micro speakers) and small speakers used in these electronic devices Demand for small electroacoustic transducers such as receivers, microphones and earphones is increasing. Polyetherimide (PEI) resin, polyetheretherketone (PEEK) resin and the like are widely used for diaphragms used in these electroacoustic transducers.

Further, in recent years, the use of silicone resin for the above-described diaphragm has also been considered. For example, Patent Document 1 discloses a sheet for a diaphragm formed by laminating in order a release sheet, a first layer composed of an uncured liquid silicone composition, and a second layer mainly containing a thermoplastic polyurethane, and a vibrating sheet for this diaphragm. A method for manufacturing a diaphragm using a plate sheet is disclosed. In Patent Literature 1, a diaphragm is manufactured by separating a release sheet from a molding after a sheet for a diaphragm is set in a mold and shaped. Since the diaphragm sheet described in Patent Document 1 uses an uncured liquid silicone composition, it is possible to improve the shapeability during molding and also to improve mold followability. .

JP 2018-152817 A

As described above, in Patent Literature 1, the sheet for diaphragm is shaped by placing the release film laminated on the first layer made of the uncured liquid silicone composition in a mold. Therefore, it is necessary to peel off the release film after molding, but the release film often becomes difficult to peel off from the first layer due to the heat and pressure during molding, resulting in poor work efficiency and a problem in mass production. Become.

Therefore, it is desirable that the diaphragm sheet is set in a mold such as a mold after peeling off the release film. However, without the release film, the first layer of the uncured liquid silicone composition sticks to the mold, causing problems such as difficulty in removing the molded product from the mold. Furthermore, the diaphragm sheet of Patent Literature 1 does not have a release film, and the shape retainability before shaping is low.
On the other hand, even if a hardening layer is provided on the surface of the sheet surface that is in contact with the mold in consideration of releasability from the mold, when the release film is peeled off before shaping, the hardening layer and the sheet However, there is a problem that peeling may occur.

Therefore, the present invention is to prevent delamination of a multilayer film when peeling off a release film before molding, while improving shape retention before molding, shapeability during molding, and conformability to a mold. An object of the present invention is to provide a film capable of

As a result of intensive studies, the present inventors found that, in a film having a curable silicone layer (A) and a silicone layer (B), the arithmetic of at least one surface between the silicone layer (A) and the silicone layer (B) The above problem can be solved by setting the average height (Sa) to a specific range, or the delamination strength to a specific range, and the storage elastic modulus E' at 20 ° C. and 10 Hz to a specific range, The following invention has been completed.

That is, the present invention provides the following [1] to [18].
[1] Another silicone layer (B) is provided on at least one surface of the curable silicone layer (A), and has the following viscoelastic properties of (a), the silicone layer (A) and the silicone layer (B) A film having an arithmetic mean height (Sa) of 500 to 4000 nm on at least one plane between the layers.
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.
[2] Another silicone layer (B) is provided on at least one side of the curable silicone layer (A), and has the following viscoelastic properties of (a), the silicone layer (A) and the silicone layer (B) A film having an interlayer peel strength of 0.5 N/5 cm or more.
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.
[3] The film according to [1] or [2], which has a gel fraction of 90% or less.
[4] The film according to any one of [1] to [3] above, wherein the silicone layer (B) has a gel fraction of 80% or more.
[5] The film according to any one of [1] to [4] above, wherein the silicone layer (B) has the following viscoelastic properties of (b).
(b) Storage modulus E' (1 Hz) at a measurement temperature of 20°C and a frequency of 10 Hz is 0.1 MPa to 500 MPa.
[6] The film according to any one of [1] to [5] above, which has thermosetting properties.
[7] The film according to any one of [1] to [6] above, which has a crosslinked structure.
[8] The film according to any one of [1] to [7] above, comprising the silicone layer (B) on both sides of the silicone layer (A).
[9] The film according to any one of [1] to [8] above, which has the following viscoelastic properties (c) to (e) after curing.
(c) Storage elastic modulus _E′20 at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa or more and 500 MPa or less.
(d) Storage modulus E′100 at a measurement temperature of 100° C. and a frequency of ₁₀ Hz is 0.1 MPa or more and 500 MPa or less.
(e) The ratio of the storage modulus _E'100 to the storage modulus _E'20 ( _E'100 / _E'20 ) is 0.4 or more and 1.0 or less.
[10] The film according to any one of [1] to [9], which is a diaphragm film.
[11] A film with a release film, comprising the film according to any one of [1] to [10] above and a release film provided on at least one side of the film.
[12] A diaphragm obtained by curing the film according to any one of [1] to [10] above.
[13] A laminate obtained by placing the film according to any one of [1] to [10] above in a mold and thermoforming the film.
[14] A molded article obtained by peeling the laminate from the mold of the laminate described in [13] above.
[15] A diaphragm comprising the molded article according to [14] above.
[16] An acoustic transducer comprising the diaphragm according to [12] or [15] above.
[17] The following (a ), a method for producing a film having viscoelastic properties of
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.
[18] The arithmetic mean height (Sa) of both surfaces of the silicone layer (B) is 500 to 4000 nm. ), a method for producing a film having viscoelastic properties of
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.

According to the present invention, it is possible to prevent delamination of the multilayer film when peeling off the release film before molding, while improving the shape retention before molding, the shapeability during molding, and the conformability to the mold. It is possible to provide a film that can be

1 is a cross-sectional view showing the structure of a microspeaker diaphragm 1 according to an embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view showing the structure of a microspeaker diaphragm 11 according to another embodiment of the present invention; FIG. 4 is a plan view showing the structure of a microspeaker diaphragm 21 according to another embodiment of the present invention;

Embodiments of the present invention will be described below, but the present invention is not limited to the embodiments described below as long as the gist of the present invention is not exceeded.
In addition, since the boundary between a film and a sheet is not clear, in the present invention, the film includes the sheet.

[the film]
One aspect of the film of the present invention (hereinafter also referred to as the present film) is provided with a silicone layer (B) on at least one side of a curable silicone layer (A), and a storage modulus at a measurement temperature of 20 ° C. and a frequency of 10 Hz. E′ has viscoelastic properties of 0.1 MPa to 500 MPa, and the arithmetic mean height (Sa) of at least one plane between the silicone layer (A) and the silicone layer (B) is 500 to 4000 nm. When the arithmetic mean height (Sa) is 500 nm or more, delamination between the silicone layer (A) and the silicone layer (B) can be prevented. On the other hand, when it is 4000 nm or less, the appearance of the film is not impaired. From the above viewpoints, the arithmetic mean height of at least one plane between the layers is preferably in the range of 600 to 3500 nm, more preferably in the range of 700 to 3000 nm, and more preferably in the range of 800 to 2500 nm. Especially preferred.
Here, at least one surface between the silicone layer (A) and the silicone layer (B) refers to the surface of the silicone layer (A) facing the silicone layer (B) or the surface of the silicone layer (B). It refers to the side facing the silicone layer (A).
The film of the present invention is formed by laminating the same type of silicone layers, and as described above, the arithmetic mean height (Sa) is within the above range, so that the interlayer thickness between the silicone layer (A) and the silicone layer (B) is Adhesion becomes extremely good.
In the present invention, it is sufficient that at least one surface between the silicone layer (A) and the silicone layer (B) is within the above range, but the silicone layer (A) is curable and the shape of the surface can be changed. It is preferable that the surface of the silicone layer (B) is within the above range.

The film may have a silicone layer (B) on both sides of the silicone layer (A). good. In this case, the arithmetic mean height (Sa) of any plane between at least one layer may be within the above range, but between both layers, the arithmetic mean height (Sa) of any plane The above range is preferred.
The curable silicone layer (A) may consist of one layer or two or more layers, but preferably consists of one layer. Therefore, the present film may have a three-layer structure of outermost layer/intermediate layer/backermost layer, or two layers between outermost and innermost layers such as outermost layer/intermediate layer/intermediate layer/backmost layer. It may have a structure of four or more layers having the above intermediate layers.
In addition, on the condition that the effect of the above arithmetic mean height (Sa) is not impaired, the present film has an adhesive layer between the silicone layer (A) and the silicone layer (B) for improving the adhesion between these layers. Other layers, such as layers, may be provided. In the case of the four-layer structure described above, another layer such as an adhesive layer may be provided between intermediate layers (between silicone layers (A) and silicone layers (A)).

The root mean square height (Sq) is preferably 500 to 5000 nm for the surface having an interlayer arithmetic mean height (Sa) of 500 to 4000 nm between the silicone layer (A) and the silicone layer (B). . When the root-mean-square height (Sq) is 500 nm or more, delamination between the silicone layer (A) and the silicone layer (B) can be further prevented. On the other hand, when it is 5000 nm or less, the appearance of the film is not impaired. From the above viewpoints, the arithmetic mean height of at least one plane between the layers is more preferably in the range of 600 to 4500 nm, more preferably in the range of 800 to 4000 nm, even more preferably in the range of 1000 to 3500 nm. is particularly preferred.

The silicone layer (A) of the present invention is a curable silicone layer, and the film maintains a certain degree of flexibility before molding, and is sufficiently cured during shaping, so that it has good shaping properties. In addition, the conformability to the mold is also improved.
Furthermore, the present film comprises a relatively hard silicone layer (B), and preferably has viscoelastic properties with a storage elastic modulus E′ of 0.1 MPa to 500 MPa at a measurement temperature of 20° C. and a frequency of 10 Hz. The flexible silicone layer is properly retained, and even without laminating a release film or the like on the film, the shape retainability before molding is improved, and the handleability is improved.
In particular, an aspect in which a silicone layer (A) is used as an intermediate layer and a relatively hard outermost and back layer (silicone layer (B)) is provided on both surfaces is more preferable, and the present film does not laminate a release film. It can be easily set in a mold and shaped, and the step of peeling off the release film after the shaping can be omitted.

Another silicone layer (B) of the present invention is a silicone layer on one side of the curable silicone layer (A). The silicone layer (B) is a curable or cured silicone layer. As described above, the silicone layer (A) is curable and its surface shape is more easily changed than the silicone layer (B). is preferred.

Further, the arithmetic average height (Sa) of the outermost surface of the film is preferably 500 to 4000 nm. When the arithmetic average height (Sa) of the outermost surface of the film is 500 nm or more, the film is removed from the mold after press molding with the film sandwiched between molds. It becomes easy to take out without sticking to. On the other hand, when it is 4000 nm or less, the appearance of the film is not impaired. From the above viewpoints, the arithmetic mean height of the silicone layer (B) on the outermost surface of the present film is preferably in the range of 600 to 3500 nm, more preferably in the range of 700 to 3000 nm, and more preferably in the range of 800 to 2500 nm. A range is particularly preferred.

(Gel fraction)
The film preferably has a gel fraction of 90% or less. When the gel fraction of the present film is 90% or less, it becomes easy to make the film flexible before molding, and the film is sufficiently hardened during molding, so that shapeability and conformability to molds are sufficient. , the moldability is improved.
From the viewpoint of formability and moldability, the gel fraction of the present film is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less. The gel fraction of the silicone layer (A) is not particularly limited, and may be 0% or more, but may be, for example, 10% or more, or may be 20% or more.

In this film, the gel fraction of the silicone layer (B) is preferably 80% or more. When the gel fraction of the silicone layer (B) is 80% or more, the silicone layer (B) can be relatively hard even before the film is cured, and the shape retention property before molding can be further improved. sticking can be easily prevented.
From the above viewpoints, the gel fraction of the silicone layer (B) is more preferably 85% or more, more preferably 90% or more. The upper limit of the gel fraction of the silicone layer (B) is not particularly limited, and may be 100% or less, but generally lower than 100%, for example, 99% or less.
In the case of a three-layer film in which the silicone layer (A) is the intermediate layer and the silicone layer (B) is the outermost layer and the innermost layer (that is, the outermost layer and the innermost layer), the gel fractions of the outermost and innermost layers are different from each other. They may be the same or different.

In addition, the gel fraction can be measured in the following manner.
1) About 100 mg of a sample is collected from the entire film, the silicone layer (A) and the silicone layer (B) of the film, and the mass (a) of the sample is measured.
2) The collected sample is immersed in chloroform at 23° C. for 24 hours.
3) Remove the solid content in chloroform and vacuum dry at 50°C for 7 hours.
4) Measure the mass (b) of the solid content after drying.
5) Using the masses (a) and (b), calculate the gel fraction based on the following formula (i).

As is clear from the above measurement method, the gel fraction is calculated by including not only the crosslinked component contained in the film but also the insoluble content other than the crosslinked component such as the filler.
However, the intermediate layer of the film before curing is obtained by calculating from the ratio of the gel fraction of the entire film before curing and the outermost layer and the thickness of the layer.

(Viscoelastic properties)
This film has the following viscoelastic properties of (a).
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.
When the storage elastic modulus E′ is 0.1 MPa or more, the present film has a constant hardness as a whole, so that it can be easily peeled off from the release film, and there is less concern about breakage during peeling. . In addition, even without a release film, it becomes easy to improve the shape retention property before molding, and it becomes easy to prevent sticking to the mold after molding. Further, by setting the storage elastic modulus E′ of the present film to 500 MPa or less, the film can ensure a certain degree of flexibility, and can improve mold followability and formability during molding. From these points of view, the storage elastic modulus E′ of the present film is more preferably 0.5 MPa or more, even more preferably 0.8 MPa or more, and even more preferably 1 MPa or more. Further, it is more preferably 300 MPa or less, further preferably 200 MPa or less, further preferably 100 MPa or less, and particularly preferably 50 MPa or less.

In addition, the silicone layer (B) in the present film preferably has the following viscoelasticity (b).
(b) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.
When the storage elastic modulus E' of the silicone layer (B) is 0.1 MPa or more, it becomes easy to improve the shape retention even without a release film. In addition, by setting the storage elastic modulus E′ to 500 MPa or less, a certain degree of flexibility can be secured, and good conformability to molds and shapeability during molding can be achieved. From these points of view, the storage elastic modulus E′ of the present film is more preferably 0.5 MPa or more, even more preferably 0.8 MPa or more, and even more preferably 1 MPa or more. Further, it is more preferably 300 MPa or less, further preferably 200 MPa or less, further preferably 100 MPa or less, and particularly preferably 50 MPa or less.

In addition, the film preferably has the following viscoelastic properties (c) to (e) after curing.
(c) Storage elastic modulus _E′20 at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa or more and 500 MPa or less.
(d) Storage modulus E′100 at a measurement temperature of 100° C. and a frequency of ₁₀ Hz is 0.1 MPa or more and 500 MPa or less.
(e) The ratio of the storage modulus _E'100 to the storage modulus _E'20 ( _E'100 / _E'20 ) is 0.4 or more and 1.0 or less.

Since the present film has the viscoelastic properties of (c) above, it tends to have excellent acoustic properties such as sound quality and reproducibility when used as an acoustic member such as a vibration film. From the viewpoint of acoustic properties and handling properties after curing, the storage elastic modulus _E'20 at 20°C after curing is more preferably 1 MPa or more, more preferably 2 MPa or more, even more preferably 4 MPa or more, and 400 MPa or less. is more preferably 300 MPa or less, even more preferably 200 MPa or less, particularly preferably 100 MPa or less, and most preferably 50 MPa or less.

By having the viscoelastic properties of (d), the present film is expected to have good heat resistance and to obtain excellent acoustic properties even in a high-temperature environment.
The storage modulus _E'100 is more preferably 1 MPa or more, more preferably 1.5 MPa or more, still more preferably 2.5 MPa or more, more preferably 400 MPa or less, still more preferably 300 MPa or less, and even more preferably 200 MPa or less. 100 MPa or less is particularly preferred, and 50 MPa or less is most preferred.

In addition, since the present film has the above viscoelastic property (e), the change in elastic modulus due to temperature change is small, and the heat resistance tends to be good. In addition, since the change in elastic modulus when heated is small, the sound quality is less likely to deteriorate in a high-temperature environment, making it easier to achieve excellent sound reproduction from low temperature ranges to high temperature ranges.
The ratio (E' ₁₀₀ /E' ₂₀ ) is more preferably 0.5 or more, still more preferably 0.6 or more, and even more preferably 0.65 or more. Also, it is more preferably 0.99 or less, still more preferably 0.97 or less, even more preferably 0.95 or less, and particularly preferably 0.93 or less.

(Peeling resistance)
Another embodiment of the film of the present invention comprises a silicone layer (B) on at least one side of the curable silicone layer (A), and has a storage modulus E′ of 0.1 MPa at a measurement temperature of 20° C. and a frequency of 10 Hz. It has viscoelastic properties of up to 500 MPa, and the delamination strength between the silicone layer (A) and the silicone layer (B) is 0.5 N/5 cm or more.
In the present film, since the surfaces between the silicone layer (A) and the silicone layer (B) have a specific concave-convex structure, the separation resistance between the layers is also good. Specifically, the delamination strength between the silicone layer (A) and the silicone layer (B) is preferably 0.5 N/5 cm or more, more preferably 1 N/5 cm or more, and 2 N/5 cm or more. is more preferred. When the delamination strength is 0.5 N/5 cm or more, delamination between the silicone layer (A) and the silicone layer (B) does not occur, improving handleability. In particular, delamination of the multilayer film can be prevented when the release film is peeled off before molding. Note that there is no limit to the upper limit. Cohesive failure may occur instead of delamination when trying to peel.
Also, the delamination strength can be measured by the method described in Examples.

This film has curability by having a curable silicone layer (A). The film may be photo-curing, moisture-curing, or thermosetting, but thermosetting is preferred. Since the present film has thermosetting properties, it can be cured when it is shaped while being heated, so that the shapeability is further improved. In addition, when this film has a thermosetting property, its gel fraction is increased by being heated. In the present film, at least the intermediate layer should have thermosetting properties, but the outermost and back layers may also have thermosetting properties as appropriate.

In this film, the silicone layer (B) preferably has a crosslinked structure. Having a crosslinked structure in the silicone layer (B) facilitates improvement in shape retention before curing (that is, before molding). In the present film, the silicone layer (B) preferably constitutes the outermost and backing layers, and therefore the outermost and backing layers preferably have a crosslinked structure. By having the crosslinked structure in the outermost and back layers, it becomes easy to improve the shape retainability of the film without significantly impairing the flexibility of the film before curing. Moreover, since the outermost and back layers have a crosslinked structure, it becomes easier to adjust the gel fraction of the outermost and back layers within the desired range described above.

The thickness of the present film is not particularly limited, but is preferably 5 μm or more and 500 μm or less, more preferably 15 μm or more and 400 μm or less, and even more preferably 30 μm or more and 300 μm or less. If the thickness of the film is within such a range, it is possible to manufacture a molded article having a thickness suitable for acoustic members, particularly diaphragms.

When the present film is a multilayer film having three or more layers, the thickness of the intermediate layer is not particularly limited, but is preferably 3 μm or more and 300 μm or less, more preferably 5 μm or more and 200 μm or less, and 20 μm or more and 150 μm or less. It is even more preferable to have By setting the thickness of the intermediate layer to the above lower limit or more, an uncured portion having a certain thickness or more and high flexibility is provided in the film. It becomes easy to improve followability to. In addition, by making the thickness equal to or less than the above upper limit, it is possible to prevent the portion having high flexibility from becoming thicker than necessary, thereby making it easier to improve the shape retainability before molding. The thickness of the intermediate layer is the total thickness when there are two or more intermediate layers.

Also, the ratio of the thickness of the intermediate layer to the thickness of the entire film (intermediate layer/entire film) is preferably 4/10 or more, more preferably 5/10 or more, and even more preferably 6/10 or more. By setting the thickness ratio (intermediate layer/entire film) to the above lower limit or more, a portion with high flexibility is provided in the film at a certain rate or more. It becomes easier to improve the followability of The thickness ratio (intermediate layer/whole film) is preferably 9.8/10 or less. By setting the thickness ratio (intermediate layer/entire film) to the above upper limit value or less, it becomes easier to make the thickness of the outermost layer and back layer greater than or equal to a certain value.

The thickness of each of the outermost and back layers is not particularly limited, but is preferably 1 μm or more and 150 μm or less, more preferably 1 μm or more and 60 μm or less, and even more preferably 1 μm or more and 30 μm or less. By making the thickness of each of the outermost and backing layers equal to or greater than the above lower limit, the shape retention property before molding can be improved, and sticking to the mold can be easily prevented. Further, by making the thickness equal to or less than the above upper limit, it is possible to prevent the portion having a certain hardness or more from becoming thicker than necessary, and it becomes easy to improve the shapeability and the conformability to the mold at the time of molding.

The thickness of each of the outermost and back layers is preferably smaller than the thickness of the intermediate layer, and the ratio of the thickness of each outermost and back layer to the thickness of the intermediate layer (each outermost and back layer/intermediate layer) is preferably 1/50 or more and less than 1. is. If the thickness of each of the top and bottom layers is smaller than the thickness of the intermediate layer, the highly flexible portion of the film will be included at a certain thickness ratio, improving shapeability and followability to the mold during molding. make it easier to Further, when the ratio (outermost and back layer/intermediate layer) is set to the above lower limit or more, the shape retainability before molding can be improved.
From these points of view, the ratio (outermost and back layers/intermediate layer) is more preferably 1/50 or more and 3/5 or less, further preferably 1/5 or more and 2/5 or less.

The intermediate layer and the outermost and back layers of this film are silicone layers and are made of silicone resin. Moreover, other resins can be used in combination with the silicone resin as long as the effects of the present invention are not impaired. The other resin is preferably a curable resin, more preferably a thermosetting resin. Among them, preferred specific examples include epoxy resin, urethane resin, acrylic resin, phenol resin, unsaturated polyester resin, polyimide resin, and melamine resin. One or more of these resins may be used in combination with the silicone resin in each layer of the film.

Since the present film is composed of a silicone film, it has good heat resistance and mechanical strength, and easily satisfies the viscoelastic properties (a) to (e) described above. In addition, it becomes easier to adjust the delamination strength within the above-described desired range.

(organopolysiloxane)
Silicone resins used in silicone layers (A) and (B) include organopolysiloxanes.
Organopolysiloxane has, for example, a structure represented by the following formula (ii).
_{RnSiO (4-n)/2} (ii)
Here, R may be the same or different, a substituted or unsubstituted monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms, more preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, n is a positive number between 1.95 and 2.05.

R is, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and a dodecyl group; a cycloalkyl group such as a cyclohexyl group; an alkenyl group such as a vinyl group, an allyl group, a butenyl group and a hexenyl group; aryl groups such as phenyl group and tolyl group, aralkyl groups such as β-phenylpropyl group, and some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc. chloromethyl group, trifluoropropyl group, cyanoethyl group and the like.

It is also preferred that the organopolysiloxane has a molecular chain end blocked with a trimethylsilyl group, a dimethylvinyl group, a dimethylhydroxysilyl group, a trivinylsilyl group, or the like. Also, the organopolysiloxane preferably has at least two alkenyl groups in the molecule. Specifically, in R, 0.001 mol% or more and 5 mol% or less, preferably 0.005 mol% or more and 3 mol% or less, more preferably 0.01 mol% or more and 1 mol% or less, especially It preferably contains 0.02 mol % or more and 0.5 mol % or less of alkenyl groups, and most preferably contains vinyl groups. Organopolysiloxane is basically linear diorganopolysiloxane, but may be partially branched. A mixture of two or more different molecular structures may also be used.

The organopolysiloxane in the outermost and back layers (silicone layer (B)) is preferably crosslinked with a crosslinking agent or the like, preferably with an organic peroxide. Therefore, each of the top and bottom layers is preferably a cured product obtained by curing a resin composition comprising an organopolysiloxane and a cross-linking agent such as an organic peroxide. At this time, the top and bottom layers are preferably cured so that the gel fraction is within the above desired range. Therefore, most of the organic peroxide blended in the top and bottom layers is decomposed, and the organic peroxide is not contained in each of the top and bottom layers, or is contained in a small amount.

On the other hand, in the intermediate layer (silicone layer (A)), the organopolysiloxane is preferably in an uncrosslinked state or in a partially crosslinked state even if crosslinked. Therefore, the intermediate layer is preferably made of a resin composition comprising an organopolysiloxane and a cross-linking agent such as an organic peroxide. In this case, the intermediate layer has a gel fraction within the above desired range. , it may be uncured, or even if it is cured, it may be in a semi-cured state. Therefore, it is preferable that the organic peroxide blended in the intermediate layer is contained in the intermediate layer in the form of organic peroxide without being decomposed.

Examples of organic peroxides include di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t- butylperoxy)hexane and other alkyl peroxides, and 2,4-dicumyl peroxide and other aralkyl peroxides. 2,5-dimethyl-2,5-di(t-butylperoxy)hexane is particularly preferred.

The blending amount of the organic peroxide in the resin composition forming each of the silicone layer (A) and the silicone layer (B) is preferably 0.01% by mass or more and 10% by mass or less, based on the total amount of the resin composition. 03% by mass or more and 5% by mass or less is more preferable, 0.05% by mass or more and 4% by mass or less is even more preferable, 0.1% by mass or more and 3% by mass or less is particularly preferable, and 0.3% by mass or more and 2% by mass or less is particularly preferred. If the blending amount of the organic peroxide is within such a range, there is a tendency to safely obtain a composition having a sufficient curing speed. As described above, the organic peroxide blended in the resin composition is almost decomposed and hardly contained in the outermost and back layers. should be contained.

The resin composition is preferably of a millable type containing organopolysiloxane. The millable resin composition in an uncured state is non-liquid (for example, solid or pasty) without self-fluidity at room temperature (25° C.), but can be uniformly mixed with a kneader to be described later. By using a millable type resin composition in the present film, as will be described later, productivity is improved when the resin composition is processed into the intermediate layer or the top and bottom layers.

In addition, in the above, the resin composition used in each of the intermediate layer and the outermost and back layers may be used in combination with a resin other than a silicone resin (organopolysiloxane) as described above. The layer may be, for example, a layer obtained by curing a resin composition containing a resin and a cross-linking agent so that the gel fraction is within a desired range. Similarly, the intermediate layer may be formed from a resin composition containing a resin and a cross-linking agent. It may be cured, or even if it is cured, it should be in a semi-cured state.

The silicone layer (A) and silicone layer (B) of the present invention may each contain a filler such as a silica-based filler. By containing a filler in each layer of the film, the storage modulus of the film and mechanical properties such as peeling resistance can be easily controlled within appropriate ranges. Moreover, by using a filler, it becomes easy to adjust the viscosity and hardness of the resin composition, and it becomes easy to optimize the balance between the fluidity and the secondary workability of the resin composition. Furthermore, there is an advantage that the hardness can be easily adjusted according to the design and acoustic characteristics of the acoustic member.
In addition, the filler constitutes a part of the gel content in the measurement of the gel fraction, and the gel fraction of each layer is increased by containing the filler. By containing a filler, even if the gel fraction is increased, the hardness of each layer can be increased in the same manner as when the gel fraction is increased by cross-linking.

Silica-based fillers include, for example, fumed silica and precipitated silica, and may be silica-based fillers surface-treated with a silane coupling agent.
The content of the filler in each layer is, for example, 10% by mass or more and 50% by mass or less, preferably 15% by mass or more and 40% by mass or less, more preferably 20% by mass or more and 35% by mass, based on the total amount of the resin composition constituting each layer. % or less. The average particle size of the filler is, for example, 0.01 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less, more preferably 0.5 μm or more and 5 μm or less. The average particle size of the filler can be measured as a median size (D50) using a particle size distribution measuring device such as a laser beam diffraction method.

In the present invention, the resin composition for forming each layer contains a heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, an antibacterial/antifungal agent, and an antistatic agent, as long as the effects of the present invention are not impaired. , lubricants, pigments, dyes, flame retardants, and impact modifiers.

In this film, the silicone resin compositions for forming the outermost layer and the innermost layer may have the same composition, or may have different compositions. Similarly, the silicone resin composition for forming the intermediate layer may have the same composition as the resin composition for forming the outermost layer or the innermost layer, or may have a different composition. The composition of the silicone resin composition here means the composition before the resin composition is cured.

In the present invention, a commercially available organopolysiloxane can also be used. Moreover, in addition to the organopolysiloxane, a commercially available mixture containing an additive such as a silica-based filler may also be used. Specifically, trade names such as “KE-597-U” and “KE-594-U” manufactured by Shin-Etsu Chemical Co., Ltd. can also be used.

[Film with release film]
The present film described above may be attached with a release film and used as a film with a release film. A film with a release film includes the main film described above and a release film provided on at least one side of the main film.
Moreover, in the film with a release film, it is preferable that release films are provided on both sides of the film. The release film is laminated on the outermost layer, the innermost layer, or both of the film.

The release film may be a resin film or a film having a release layer obtained by subjecting at least one surface of the resin film to release treatment. When the release film has a release layer, it is preferably laminated on the film so that the release layer is in contact with the outermost and back layers of the film.
Resins used for resin films include polyolefin resins such as polypropylene, acrylic resins, polystyrene resins, polyacetal resins, polyamide resins, polyester resins, polycarbonate resins, ABS resins, and polyether ether ketone resins. etc. can be exemplified. Among these, polyester-based resins are preferable, and polyethylene terephthalate-based resins are particularly preferable.
The thickness of the release film is not particularly limited, but is preferably from 5 μm to 100 μm, more preferably from 7 μm to 80 μm, and even more preferably from 10 μm to 50 μm.

The film is protected by the release film by attaching the release film. Therefore, the film is prevented from being damaged during transportation. As for the release film, as described later, the release film laminated on the outermost and back layers when producing the film may be used as it is, or may be laminated separately on the produced film. good.
As described later, the film is formed by, for example, forming molding, and the release film is preferably peeled off from the film at the time of molding and then set in a mold such as a mold. Even without a release film, the present film has a predetermined outermost and back layer as described above, so that the shape retainability is good even before curing. In addition, as described above, the present film prevents separation between the silicone layer (A) and the silicone layer (B) when the release film is peeled off.
As described below, by using a release film having unevenness, when a silicone layer is laminated on the release film, the unevenness of the release film can be transferred to the silicone layer.

[Manufacturing method of this film]
A method for producing the present film will be described below, but the method for producing the present film is not limited to the method described below.
One aspect of the production method of the present film is that at least one side of the silicone layer (B) has an arithmetic mean height (Sa) of 500 to 4000 nm, and a curable silicone layer (A) is laminated on the one side. and having a storage modulus E′ of 0.1 MPa to 500 MPa at a measurement temperature of 20° C. and a frequency of 10 Hz.
In another aspect of the production method of the present film, the arithmetic mean height (Sa) of both surfaces of the silicone layer (B) is 500 to 4000 nm, and the curable silicone layer (A) is formed on both surfaces. This is a method for producing a film having viscoelastic characteristics with a storage elastic modulus E′ of 0.1 MPa to 500 MPa at a measurement temperature of 20° C. and a frequency of 10 Hz obtained by lamination.
The present film can be molded by a general molding method, for example, lamination molding, extrusion molding such as co-extrusion, coating, or a combination thereof. Among these, it is preferable to use lamination molding in consideration of the easiness of multi-layering of the outermost layer and the intermediate layer.
Further, as a method for forming unevenness, a silicone layer (B) having unevenness formed so that the arithmetic mean height (Sa) is in a specific range of 500 to 4000 nm is prepared in advance, and the silicone layer (A ) is laminated. Furthermore, a silicone layer (A) having irregularities formed so that the arithmetic mean height (Sa) is within a specific range is prepared, and the silicone layer (B) is laminated thereon to form the silicone layer (A). Examples include a method of transferring unevenness to the silicone layer (B) to form unevenness.
The method of forming unevenness is not particularly limited, and unevenness may be formed by embossing or the like, or by forming a silicone layer on a release film having unevenness and transferring the unevenness of the release film to the silicone layer. good too.
An example of a film manufacturing method using lamination molding will be specifically described below. In the following, in a film having a three-layer structure of outermost layer/intermediate layer/backer layer, the unevenness of the release film is transferred to the silicone layer (B) (outermost back layer) to form unevenness on the silicone layer. A method of preparing (B) and laminating the silicone layer (A) on it will be described, but the method is not limited to the following method.

When lamination molding is used, it is preferable to first prepare an outermost layer and an innermost layer, and then laminate an intermediate layer between the outermost layer and the innermost layer.
More specifically, first, a resin composition for obtaining the outermost layer and the outermost layer (resin composition for the outermost layer or the innermost layer), and a resin composition for obtaining the intermediate layer (resin for intermediate layer composition) should be prepared.

Each resin composition is not particularly limited, but can be obtained, for example, by kneading materials constituting the resin composition. Kneaders used for kneading include extruders such as single-screw or twin-screw extruders, calender rolls such as two-roller and three-roller rolls, roll mills, plastmills, Banbury mixers, kneaders, planetary mixers, and other known kneaders. machine can be used.
The kneading temperature is appropriately adjusted according to the type and mixing ratio of the resin and the presence and type of additives. It is preferably 150° C. or higher, more preferably 30° C. or higher and 140° C. or lower, even more preferably 40° C. or higher and 130° C. or lower, particularly preferably 50° C. or higher and 120° C. or lower. ° C. or more and 110° C. or less is particularly preferable.
The kneading time may be such that the materials constituting the resin composition are uniformly mixed, and is, for example, several minutes to several hours, preferably 5 minutes to 1 hour.

The resin composition for the outermost layer or the innermost layer prepared as described above is laminated on a release film by a general method to obtain a laminate, and then the laminate is heated to obtain a resin. The composition may be cured. As a result, a laminate (hereinafter also referred to as "laminated film") is obtained in which the outermost layer or the innermost layer is laminated on the release film. In the laminated film, it is preferable that the outermost layer or the innermost layer is cured to form a cross-linked structure and have a gel fraction of 80% or more as described above.
When the release film has a release-treated surface, the resin composition for the outermost and back layers is preferably laminated on the release-treated surface of the release film.
Further, in the present production method, as described above, the resin composition for the outermost and back layers is laminated on the release film and cured, so that the surface of the outermost and back layer obtained has a shape corresponding to the surface shape of the release film. shape. Therefore, by forming an uneven shape in advance on the surface of the release film, the surface of the outermost and back layer (silicone layer (B)) is formed with unevenness.

Next, it is preferable to obtain the present film by laminating an intermediate layer formed from the intermediate layer resin composition between the laminated films by lamination molding. Specifically, the intermediate layer resin composition in an uncured or semi-cured state is put, for example, between a pair of rolls and between the laminated films fed out from two directions. Here, the intermediate layer resin composition may be introduced between the laminated films by, for example, extruding from a T-die using an extruder or the like. In addition, each laminated film is preferably fed out so that the outermost layer and the innermost layer face each other and face each other.
Then, the thickness is adjusted by the gap between the rolls as necessary, and a laminate is obtained in which an uncured or semi-cured intermediate layer is formed between the laminated films. The laminate preferably has a laminate structure of release film/outermost layer/intermediate layer/outermost layer/laminate film, and is the film with a release film described above.

Each resin composition for obtaining the silicone layer (A) and the silicone layer (B) can be obtained, for example, by kneading materials constituting the resin composition. Kneaders used for kneading include extruders such as single-screw or twin-screw extruders, calender rolls such as two-roller and three-roller rolls, roll mills, plastmills, Banbury mixers, kneaders, planetary mixers, and other known kneaders. machine can be used.
The kneading temperature is appropriately adjusted according to the type and mixing ratio of the resin and the presence and type of additives. It is preferably 150° C. or higher, more preferably 30° C. or higher and 140° C. or lower, even more preferably 40° C. or higher and 130° C. or lower, particularly preferably 50° C. or higher and 120° C. or lower. ° C. or more and 110° C. or less is particularly preferable.
The kneading time may be such that the materials constituting the resin composition are uniformly mixed, and is, for example, several minutes to several hours, preferably 5 minutes to 1 hour.

[Molding]
The present film can be formed into a molded article by molding with a mold such as a mold and curing, and typically, it is preferably formed into various molded articles by forming with a mold. Curing may be carried out according to the properties of the present film, and may be carried out by heating, light irradiation, moisturizing, or a combination thereof, preferably by heating. The molded article is preferably an acoustic member, and more preferably constitutes a diaphragm.
When obtaining a molded article from this film, it is preferable to perform at least the following steps 1 and 2.
Step 1: Heating the film to shape it with a mold and curing the film Step 2: Peeling the molded and cured film (i.e., molded product) from the mold

Each step will be described in more detail below.
(Step 1)
In step 1, the film is heated and molded with a mold, and the film is cured to form a molded product. The molded article may be formed by a mold, thereby forming the desired shape. The molding in step 1 is not particularly limited, and may be performed by any molding method such as vacuum molding, pressure molding, or press molding. Among these, press molding is preferable because molding is simpler.

As for the mold, a mold suitable for the molding method may be prepared, and the mold may be provided with unevenness or the like according to the shape of the molded article to be manufactured. As the mold, a metal mold (mold) is typically used, but a resin mold may also be used. For example, if the molded product (acoustic member) has at least one of a dome shape and a cone shape as will be described later, the mold should be provided with projections and recesses corresponding to the dome shape or the cone shape. If the molded product (acoustic member) has a tangential edge on its surface, the mold should be provided with unevenness corresponding to the tangential edge.

As described above, the present film may be attached with a release film, and the present film may be set in the mold after the release film is peeled off as described above.

In step 1, the heated film may be shaped with a mold. For example, the film placed on a mold may be shaped with a mold while being heated, or a preheated film may be placed on the mold. After that, it may be shaped by a mold, or these may be combined. In addition, the present film may be heated by any method. For example, in the case of heating the film placed on the mold, the mold may be heated and the heat may be transferred, or other methods may be used to heat the film. You may

The heating temperature during shaping or curing is preferably 180° C. or higher and 260° C. or lower, more preferably 190° C. or higher and 250° C. or lower, even more preferably 200° C. or higher and 240° C. or lower. If the temperature at the time of shaping or curing is within the range, there is a tendency that the film can be cured at a sufficient speed within the range where the film is not melt-deformed by heat.

The shaping time is preferably 1 second to 5 minutes, more preferably 5 seconds to 4 minutes, even more preferably 10 seconds to 3 minutes, and 20 seconds to 2 minutes. It is particularly preferred to have If the heat treatment time during shaping is in the range, it tends to be sufficiently hardened while maintaining productivity.
The film is preferably cured while being shaped, but is not particularly limited and may be cured after being shaped. The shaping time refers to the time during which the film is shaped or cured in the mold. shall not be included.

(Step 2)
In step 2, the film molded and cured in step 1 is removed from the mold to obtain a molded article. In the present invention, since the gel fraction of the silicone layer (A) is less than a certain value, the shapeability is high and the conformability of the film to the mold is high. Therefore, the molded product can be manufactured with high molding accuracy.
Furthermore, since the silicone layer (B) is provided, the film has high shape retention, good handleability even without a release film, and maintains the shape of the film even without a release film. It can be easily set in the mold while it is still in place. In addition, since the release film is not laminated, the step of peeling off the release film from the molded product can be omitted, which facilitates mass production.
In addition, in the present film, the arithmetic mean height (Sa) of at least one surface between the silicone layer (A) and the silicone layer (B) is 500 to 4000 nm. The adhesiveness of (B) is high, and peeling between layers does not occur in the above steps 1 and 2.

In the present invention, the gel fraction of the molded article obtained from the above film should be 80% or more. When the gel fraction is 80% or more, it becomes easier to obtain a molded article having a storage elastic modulus suitable for an acoustic member and mechanical strength. The gel fraction of the molded article is more preferably 85% or more, and even more preferably 90% or more. The gel fraction of the molded product is not particularly limited as long as it is 100% or less, but generally lower than 100%, for example, 99% or less. The gel fraction of the molded product is the gel fraction of the entire molded product, and may be measured by sampling by cutting the molded product in a direction parallel to the thickness direction. The details of the method for measuring the gel fraction are as described above.

[Use of film]
The film of the present invention is preferably used for acoustic members as described above, and is particularly suitable for diaphragms. The acoustic member of the present invention is obtained by curing the present film, and specifically, it is preferable to consist of the above-described molded article. The diaphragm is more preferably a speaker diaphragm, and can be particularly suitably used as a microspeaker diaphragm for mobile phones and the like.

This film can be used as various acoustic members such as diaphragms by being appropriately molded.
For example, at least a portion of the acoustic member may have a dome shape, a cone shape, or the like. Also, the acoustic member may have a tangential edge on its surface. Having a dome shape or cone shape, or having a tangential edge, the acoustic member is preferably used for a diaphragm, more preferably for a speaker diaphragm.

(diaphragm)
To explain the diaphragm in more detail, the shape of the diaphragm is not particularly limited and can be selected from a circular shape, an elliptical shape, an oval shape, and the like. Also, the diaphragm generally has a body that vibrates in response to an electrical signal or the like, and an edge that surrounds the body. The diaphragm body is usually supported by the edges. The shape of the diaphragm may be, as described above, a dome shape, a cone shape, a combination of these shapes, or any other shape used for the diaphragm.

The film may form at least a part of the diaphragm. For example, the body or edge of the diaphragm may be formed by the film, and the edge or body of the diaphragm may be formed by another member. Of course, both the body and the edge may be integrally formed by this film, or the entire diaphragm may be formed by this film.

FIG. 1 is a diagram showing the structure of a diaphragm 1 according to an embodiment of the present invention, and is a cross-sectional view of a diaphragm 1 that is circular in plan view and cut along a plane passing through the center line of the circle. A diaphragm 1 is a diaphragm for a micro speaker. As shown in FIG. 1, the diaphragm 1 has a dome portion (body) 1a in the center, a recessed fitting portion 1b attached to the voice coil 2, a peripheral portion (edge) 1c, and an external portion attached to a frame or the like around the periphery. It has a sticking portion 1d.

FIG. 2 is a diagram showing the structure of the diaphragm 11 in another embodiment of the present invention, and is a cross-sectional view of the diaphragm 11, which is circular in plan view, cut along a plane passing through the center line of the circle. The diaphragm 11 is a microspeaker diaphragm. As shown in FIG. 2, the diaphragm 11 has a dome-shaped dome portion (body) 11a at the center, a recessed fitting portion 11b attached to the voice coil 2, a cone-shaped cone portion 11j, and It has a peripheral portion (edge) 11c. As exemplified by the diaphragm 11, the diaphragm may be partly processed into a dome shape and other part thereof may be processed into a cone shape. The diaphragm 11 may be attached directly to the frame or the like at the peripheral edge portion 11c, or may be attached to the frame or the like via another member.

The surface of the diaphragm may be provided with a tangential edge as described above. The tangential edge may be configured by, for example, a groove having a V-shaped cross section. FIG. 3 shows a plan view of a diaphragm 21 according to another embodiment of the invention. The diaphragm 21 includes a tangential edge portion 21g in which a plurality of tangential edges 21e are provided on the outer peripheral edge of a circular dome portion (body) 21a, and a plurality of tangential edges arranged on the outer periphery of the tangential edge portion 21g. It has a tangential edge portion 21h provided with a tangential edge 21f. Although FIG. 3 shows an example in which two tangential edge portions are provided along the radial direction, only one tangential edge portion may be provided along the radial direction, or three or more tangential edge portions may be provided along the radial direction. may

The diaphragm is preferably a speaker diaphragm, especially a microspeaker diaphragm, as described above. From the viewpoint of suitable use as a microspeaker diaphragm, the maximum diameter of the diaphragm is 25 mm or less, preferably 20 mm or less, and the maximum diameter is preferably 5 mm or more. The maximum diameter is the diameter when the shape of the diaphragm is circular, and the major axis when it is elliptical or oval.

The diaphragm may be formed of the present film alone, or may be formed of a composite material of the present film and other members. For example, either the edges or the body may be formed from other members as described above.

Furthermore, in order to make the diaphragm suitable for secondary processing, dustproof, adjust the acoustic characteristics, and improve the design, the surface of the diaphragm is coated with an antistatic agent, metal is vapor-deposited, or sputtered. , coloring (black, white, etc.) may be performed as appropriate. Furthermore, lamination with a metal such as aluminum, or combination with a non-woven fabric, or the like may be carried out as appropriate.

(acoustic transducer)
The acoustic transducer of the present invention is an acoustic transducer comprising the above-described acoustic member, preferably a diaphragm. Acoustic transducers are typically electroacoustic transducers and include speakers, receivers, microphones, earphones, and the like. Among these, the acoustic transducer is preferably a speaker, preferably a microspeaker such as a mobile phone.

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

[Evaluation and measurement method]
In this example, various physical properties were measured and films were evaluated as follows.

(1) Measurement of gel fraction According to the method described in the specification, the gel fraction of the entire film before curing, the gel fraction of the top and bottom layers of the film before curing, and the gel fraction of the entire film after curing were measured. . When measuring the gel fraction of the entire film, sampling was performed by cutting in a direction parallel to the thickness direction of the film. In addition, the intermediate layer of the film before curing was obtained by calculation from the ratio of the gel fractions of the entire film before curing and the top and bottom layers, and the layer thickness.

(2) Storage modulus E'
Test pieces of 4 mm×8 cm were cut out from the films before and after curing obtained in each of Examples and Comparative Examples, and obtained as measurement samples. Using the measurement sample, in compliance with JIS K7244-4: 1999, using a viscoelastic spectrometer "DVA-200 (manufactured by IT Instrument Control Co., Ltd.)", the measurement mode is tensile, the frequency is 10 Hz, and the strain is 0. .1%, the temperature range was -100 to 300°C, the temperature was raised at a heating rate of 3°C/min, and the storage modulus of the film before curing was measured at 20°C. In addition, the storage elastic modulus at 20°C and 100°C was measured for the cured film. In addition, the measurement was performed about TD.

(3) Surface roughness (arithmetic mean height: Sa, root mean square height: Sq)
The arithmetic mean height (Sa) and the root mean square height (Sq) of the silicone layer (B) used in each example and comparative example were measured by a three-dimensional white interference microscope, "Contour 2.0" (Bruker Japan). (manufacturer), measurement was performed under the conditions of an eyepiece magnification of 1.0 times, an objective lens magnification of 20 times, and a measurement area of 235 μm (length) × 313 μm (width), and smoothing was performed using a Gaussian function. It was obtained by measuring the root mean square height. Observation mode was "Wave mode".

(4) Shape retainability The shape retainability of the films before curing obtained in each of Examples and Comparative Examples was evaluated. When this film was peeled off from the release film and used for various evaluations and measurements, it was evaluated as "○" when it was easy to operate because the shape was retained. The evaluation "X" was given when the wire was entangled or cut.

(5) Presence or Absence of Tear When producing the film in each of Examples and Comparative Examples, evaluation was performed in a state in which a release film was laminated on the outermost and back layers. The presence or absence of tearing was evaluated in the step of manually peeling off the release film of the outermost and back layers from the obtained uncured film. When the release film could be peeled off without tearing the film, it was evaluated as "O", and when the release film was removed and part of the film was torn, it was evaluated as "X".
For various evaluations and measurements other than the presence or absence of tearing, the film from which the release film was removed was used.

(6) Delamination resistance (interlayer delamination strength)
A test piece of 5 cm×10 cm was cut out from the uncured film obtained in each of Examples and Comparative Examples, and obtained as a measurement sample. The delamination strength between the silicone layer (A) and the silicone layer (B) in the measurement sample was measured using a universal tester (manufactured by Shimadzu Corporation). It was measured by a 180° peeling test at 200 mm/min under an environment of 25 mm between chucks and 23°C.

(7) Formability/Formability A test piece of about 7 cm×10 cm was cut out from the film obtained in each of Examples and Comparative Examples and used as an evaluation sample. The evaluation sample is sandwiched between a dome-shaped diaphragm mold with a tangential edge and preheated to 240° C. and pressed at a pressure of 0.6 MPa. Removed from the mold.
If the moldability and shapeability are good, it is evaluated as "O", and if it is not good, it is evaluated as "X".
(8) Adhesion to a mold A test piece of about 7 cm x 10 cm was cut out from the film obtained in each example and comparative example in the same manner as in the evaluation of moldability and shapeability described above, and used as an evaluation sample. . The sample to be evaluated was sandwiched between a mold for diaphragm preheated to 240° C. and pressed at a pressure of 0.6 MPa.

Example 1
A 20 μm thick silicone rubber (TSE2571-5U) is laminated between a pair of PET films with an arithmetic mean height (Sa) of 1600 nm for the front and back layers, and cured to prepare a laminated film. The PET film was peeled off to expose the cured silicone. At this time, the arithmetic mean height of the PET film was transferred to the silicone, and the arithmetic mean height (Sa) of the silicone was 1600 nm.

A mixture containing organopolysiloxane and silica (trade name “KE-597-U”, manufactured by Shin-Etsu Chemical Co., Ltd.) 100 parts by mass, and an organic peroxide (trade name “C-8B”, manufactured by Shin-Etsu Chemical Co., Ltd. , 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, containing about 40% by mass of an organic peroxide), using a planetary mixer, at a temperature of 90 ° C. for 10 minutes. After kneading, a millable type resin composition (1) was obtained.
The two laminated films obtained above were supplied along two calender rolls with a diameter of 100 mm so that the exposed surface of the cured silicone was on the inside, and between the calender rolls and between the laminated films, the resin composition Product (1) is put in, and a bank is formed on the roll at room temperature 25 ° C. and roll temperature 90 ° C., so that the thickness of the intermediate layer is 100 μm, release film / outermost layer / intermediate layer / outermost layer / A film with a release film made of the release film was obtained. Two release films were peeled off from the obtained film with a release film to obtain the present film. The gel fraction of the outermost and backing layers and the intermediate layer of the film, the storage elastic modulus of the present film at 20°C, and the interlayer peel strength of the intermediate layer (silicone layer (A)) and the outermost and backing layer (silicone layer (B)) was measured. Table 1 shows the measurement results.

Assuming that a molded product will be produced by molding, the film obtained above is cured by a simple method of press molding from two flat plates at a pressure of 0.2 MPa while heating at 220 ° C. for 2 minutes. let me The gel fraction (whole film) and storage elastic modulus of the obtained cured film were measured.

Example 2 and Comparative Example 1
Films were produced in the same manner as in Example 1 except that a PET film having an arithmetic mean height (Sa) of 2200 nm was used for the outermost and back layers in Example 2, and a PET film with a smooth surface was used in Comparative Example 1. .
The gel fraction of the outermost and backing layers and the intermediate layer of the film, the storage elastic modulus of the present film at 20°C, and the interlayer peel strength of the intermediate layer (silicone layer (A)) and the outermost and backing layer (silicone layer (B)) was measured. Table 1 shows the measurement results.

Assuming that a molded product will be produced by molding, the film obtained above is cured by a simple method of press molding from two flat plates at a pressure of 0.2 MPa while heating at 220 ° C. for 2 minutes. let me The gel fraction (whole film), storage elastic modulus, and delamination strength of the cured film were measured.

It can be seen that the present films of the above examples have high peel strength between the silicone layer (A) and the silicone layer (B) and have good peel resistance. On the other hand, it can be seen that the film of Comparative Example 1, which does not have unevenness between layers, has low peel strength and low peel resistance.
As for the film with a release film obtained in Comparative Example 1, when the release film was actually peeled off, separation occurred between the silicone layer (A) and the silicone layer (B).
In addition, when the sticking property to the mold was evaluated by the above method, the films of Examples 1 and 2 were easier to mold than the film of Comparative Example 1 when the evaluation sample was removed from the mold. I was able to take it out without sticking to it.

Claims (18)

At least one side of the curable silicone layer (A) is provided with another silicone layer (B),
Having the following viscoelastic properties of (a),
A film in which at least one surface between the silicone layer (A) and the silicone layer (B) has an arithmetic mean height (Sa) of 500 to 4000 nm.
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa. At least one side of the curable silicone layer (A) is provided with another silicone layer (B),
Having the following viscoelastic properties of (a),
A film in which the delamination strength between the silicone layer (A) and the silicone layer (B) is 0.5 N/5 cm or more.
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa. 3. The film according to claim 1, which has a gel fraction of 90% or less. The film according to any one of claims 1 to 3, wherein the silicone layer (B) has a gel fraction of 80% or more. The film according to any one of claims 1 to 4, wherein the silicone layer (B) has the following viscoelastic properties (b).
(b) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa. The film according to any one of claims 1 to 5, which has thermosetting properties. The film according to any one of claims 1 to 6, which has a crosslinked structure. The film according to any one of claims 1 to 7, comprising the silicone layer (B) on both sides of the silicone layer (A). The film according to any one of claims 1 to 8, which has the following viscoelastic properties (c) to (e) after curing.
(c) Storage elastic modulus _E′20 at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa or more and 500 MPa or less.
(d) Storage modulus E′100 at a measurement temperature of 100° C. and a frequency of ₁₀ Hz is 0.1 MPa or more and 500 MPa or less.
(e) The ratio of the storage modulus _E'100 to the storage modulus _E'20 ( _E'100 / _E'20 ) is 0.4 or more and 1.0 or less. The film according to any one of claims 1 to 9, which is a diaphragm film. A film with a release film, comprising the film according to any one of claims 1 to 10 and a release film provided on at least one side of the film. A diaphragm obtained by curing the film according to any one of claims 1 to 10. A laminate obtained by placing the film according to any one of claims 1 to 10 in a mold and thermoforming it. 14. A laminate according to claim 13, which is a molded article removed from the mold. A diaphragm comprising the molded article according to claim 14 . An acoustic transducer comprising the diaphragm according to claim 12 or 15. At least one side of the silicone layer (B) has an arithmetic mean height (Sa) of 500 to 4000 nm, and the following viscosity (a) obtained by laminating a curable silicone layer (A) on the one side: A method for producing a film having elastic properties.
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa. The following viscosity (a) obtained by laminating a curable silicone layer (A) on both surfaces of the silicone layer (B) having an arithmetic mean height (Sa) of 500 to 4000 nm. A method for producing a film having elastic properties.
(a) Storage elastic modulus E′ at a measurement temperature of 20° C. and a frequency of 10 Hz is 0.1 MPa to 500 MPa.

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