JP2023013675A - Thermoplastic resin film, adhesive film, and adhesive film for semiconductor manufacturing process - Google Patents

Abstract

To provide a film which is excellent in film-forming property when a resin is formed in the shape of a film, and is also excellent in flexibility, restoration property and expandability.SOLUTION: A thermoplastic resin film is composed of two or more layers, where a thermoplastic resin constituting each of the layers contains a styrenic elastomer, and a percentage content of a styrene component of the styrenic elastomer contained in front and back layers is 14 mass% or more and 60 mass% or less.SELECTED DRAWING: None

Description

The present invention provides an adhesive film (tape) used in the semiconductor manufacturing process, a sticker, a label and a marking film that are affixed to give design to signboards, automobiles, etc., adhesive films (tape), decorative sheets, etc. The present invention relates to a thermoplastic resin film suitably used as a base material of No. 1 and an adhesive film having an adhesive layer provided on the thermoplastic resin film.

Conventionally, adhesive films (tapes), stickers, labels, marking films, decorative sheets, etc., which are pasted to give design to signboards, automobiles, etc., have had colorability, workability, Films made of polyvinyl chloride resin (hereinafter also referred to as "PVC-based films"), which are excellent in scratch resistance, weather resistance, etc., are frequently used as substrates.

The PVC-based film itself has rigidity, but a plasticizer is added for the purpose of imparting flexibility so that it can function as an adhesive film. However, depending on the plasticizer used, there is a problem that the compatibility with the adhesive is poor, the stability is poor when the adhesive film is formed, and the plasticizer bleeds out significantly. In addition, there is a tendency to tighten restrictions on the use of plasticizers themselves.
Therefore, polyolefin-based resin films have been widely used as materials to replace PVC-based films.

Also, in the process of manufacturing semiconductors, adhesive films for semiconductor wafer processing are used when cutting semiconductor wafers and packages. ing.
Films using PVC-based resins and polyolefin-based resins have been developed as such films for semiconductor manufacturing processes (for example, Patent Document 1). Further, Patent Document 2 discloses a base film for a semiconductor manufacturing process, which imparts antistatic performance and is excellent in flexibility and heat resistance.

Furthermore, in recent years, semiconductor elements have become smaller and thinner, and there is a tendency to demand greater expandability of films in an expanding process for expanding the intervals between chips on a semiconductor wafer. As the size of chips becomes smaller, chips and devices are more likely to be damaged due to contact between chips, resulting in a decrease in yield and an economic impact.

In order to solve these problems, Patent Documents 3 and 4 disclose base films for dicing containing a large amount of styrene-based elastomer and having excellent expandability.

However, in the inventions described in Patent Documents 1 and 2, polyolefin resins and olefin elastomers, which are not sufficiently expandable, are the main components, and expandability is insufficient.
In addition, although the invention described in Patent Document 3 uses many styrene-based elastomers, the document does not select a material that takes into consideration the workability and handleability of the film, and the styrene-based elastomer is not used. No detailed description.
The invention described in Patent Document 4 describes that the intermediate layer is made of a styrene-based elastomer, and is described as having excellent expandability. However, there is room for improvement in the selection of the styrene-based elastomer in consideration of the film formability when molding the resin into a film.

JP-A-9-8111 JP 2020-84143 A Japanese Patent No. 4259050 JP 2018-125521 A

In view of such problems, an object of the present invention is to provide a film that is excellent in film formability when molding a resin into a film, and that is also excellent in flexibility, resilience, and expandability. Another object of the present invention is to provide a pressure-sensitive adhesive film for a semiconductor manufacturing process, which is capable of ensuring sufficient spacing between chips, since the film of the present invention is excellent in flexibility, resilience, and expandability.

As a result of intensive studies, the present inventors have found that the above problems can be solved by incorporating a specific styrene-based elastomer into a specific layer of a thermoplastic resin film consisting of two or more layers, and have completed the present invention. rice field.

That is, the gist of the present invention is as follows.
[1]
A thermoplastic resin film consisting of two or more layers,
The thermoplastic resin film, wherein the thermoplastic resin constituting each layer contains a styrene elastomer, and the styrene component content of the styrene elastomer contained in the front and back layers is 14% by mass or more and 60% by mass or less.
[2]
The thermoplastic resin film according to [1], wherein the thermoplastic resin constituting each layer is composed only of a styrene-based elastomer.
[3]
The thermoplastic resin film according to [1] or [2], wherein the thermoplastic resin constituting the front and back layers is composed only of a styrene-based elastomer having a styrene content of 14% by mass or more and 60% by mass or less.
[4]
The heat according to any one of [1] to [3], wherein the styrene-based elastomer is a block copolymer of a vinyl aromatic compound and a conjugated diene-based compound, a hydrogenated product thereof, or a mixture thereof. plastic resin film.
[5]
The thermoplastic resin film according to any one of [1] to [4], which comprises a surface layer/intermediate layer/back layer, comprising two kinds of three layers or three kinds of three layers.
[6]
An adhesive film obtained by providing an adhesive layer on at least one side of the thermoplastic resin film of any one of [1] to [5].
[7]
The pressure-sensitive adhesive film for semiconductor manufacturing processes according to [6], which is used in semiconductor manufacturing processes.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a film that is excellent in film-forming properties when molding a resin into a film, and that is also excellent in flexibility, resilience, and expandability. In addition, since the film of the present invention is excellent in flexibility, resilience, and expandability, it is possible to provide an adhesive film for semiconductor manufacturing processes capable of ensuring sufficient intervals between chips.

Although the present invention will be described in detail below, the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist thereof. In addition, when the expression "~" is used in this specification, it is used as an expression including numerical values or physical property values before and after it.

One embodiment of the present invention is a thermoplastic resin film consisting of two or more layers, wherein the thermoplastic resin constituting each layer contains a styrene-based elastomer, and the styrene-based elastomer contained in the front and back layers contains a styrene component. The thermoplastic resin film (hereinafter also referred to as the "thermoplastic resin film of the present invention") is characterized by having a content of 14% by mass or more and 60% by mass or less.

<Styrene-based elastomer>
The styrene elastomer used in the thermoplastic resin film of the present invention is a block copolymer of a vinyl aromatic compound constituting the hard segment and a conjugated diene compound constituting the soft segment, a hydrogenated product thereof, and a mixture thereof. Either is preferable. A hydrogen additive is more preferable from the viewpoint of preventing deterioration due to heat during film formation and contamination of the film with the deteriorated product.

The hydrogenated styrene elastomer may be partially hydrogenated (partially hydrogenated) or completely hydrogenated (completely hydrogenated).
Whether to use a partially hydrogenated one, to use a completely hydrogenated one, or to use both together can be appropriately selected from the viewpoint of the use of the film, moldability, and the like. From the viewpoint of deterioration during molding as described above, it is preferable to use a completely hydrogenated one.

The block copolymer described above is preferably a block copolymer represented by the following formula (I) or (II).
X-(Y-X)n ... (I)
(X-Y)n ... (II)
X in general formulas (I) and (II) is a vinyl aromatic polymer block represented by styrene (hereinafter referred to as a styrene component). may be different. Y is butadiene polymer block, isoprene polymer block, butadiene/isoprene copolymer block, hydrogenated butadiene polymer block, hydrogenated isoprene polymer block, hydrogenated butadiene/isoprene copolymer block. It is at least one selected from coalesced blocks, partially hydrogenated butadiene polymer blocks, partially hydrogenated isoprene polymer blocks and partially hydrogenated butadiene/isoprene copolymer blocks. Also, n is an integer of 1 or more.

Specific examples of styrene elastomers include styrene-ethylene/butylene-styrene copolymers, styrene-ethylene/propylene-styrene copolymers, styrene-ethylene/ethylene/propylene-styrene copolymers, styrene-butadiene-butene- Styrene copolymer, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-hydrogenated butadiene diblock copolymer, styrene-hydrogenated isoprene diblock copolymer, styrene-butadiene diblock copolymers, styrene-isoprene diblock copolymers, etc. Among them, styrene-ethylene/butylene-styrene copolymers, styrene-ethylene/propylene-styrene copolymers, styrene-ethylene/ethylene/propylene-styrene Copolymers, styrene-butadiene-butene-styrene copolymers, are preferred. A block copolymer, which is a styrene-ethylene/butylene-crystalline olefin copolymer, can also be used.

In the present invention, the front and back layers of the thermoplastic resin film are required to contain a styrene-based elastomer having a styrene component content of 14% by mass or more and 60% by mass or less.
By using a styrene-based elastomer with a styrene component content of 14% by mass or more in the front and back layers, the front and back layers of the film do not become too flexible, and the film is prevented from sticking to rolls, etc. during transportation. becomes possible, and it becomes easy to obtain a film. In addition, if the content of the styrene component is 60% by mass or less, the flexibility and resilience of the styrene-based elastomer are not impaired, and it is possible to impart appropriate flexibility, resilience, and expandability to the resulting film. becomes. A styrene-based elastomer having a styrene component content of 14% by mass or more and 60% by mass or less is hereinafter also referred to as "styrene-based elastomer (A)".

The lower limit of the content of the styrene component in the styrene elastomer (A) is preferably 15% by mass or more, more preferably 16% by mass or more, and the upper limit is preferably 55% by mass or less, more preferably 50% by mass or less.
The content of the styrene-based elastomer (A) in the resin composition constituting the front and back layers is preferably 50% by mass or more and 100% by mass or less in 100% by mass of the thermoplastic resin constituting the resin composition. By containing 50% by mass or more of the styrene-based elastomer (A), the front and back layers do not become too soft as described above, and sticking to rolls or the like during transport of the film can be suppressed. From the viewpoint of flexibility and adhesion to rolls, the thermoplastic resin constituting the resin composition may be 100% by mass of the styrene-based elastomer (A).
The content of the styrene-based elastomer (A) in the resin composition constituting the front and back layers is more preferably 60% by mass or more and 100% by mass or less in 100% by mass of the thermoplastic resin constituting the resin composition, and is 70% by mass. More preferably, it is more than 100% by mass or less.
In addition, the content of the styrene elastomer (A) in the resin composition constituting each layer of the surface layer and the back layer or the thermoplastic resin constituting the resin composition may be the same or different. good. If the content of the styrene-based elastomer (A) is within the above range, the type and amount of the styrene-based elastomer to be used can be appropriately adjusted for each layer on the front and back depending on the performance of the film to be obtained and the film formability of the film. can be selected.

The content of the styrene component and the content of other components can be measured by using ¹ H-NMR or ¹³ C-NMR. Here, the "styrene component content" refers to the content (% by mass) of a vinyl aromatic polymer block represented by styrene based on the mass of the styrene elastomer.

The melt flow rate of the styrene elastomer (value measured under a load of 2.16 kg under temperature conditions of 230°C or 190°C) is preferably 0.1 to 10 g/10 min, more preferably 0.15 to 9 g/10 min. minutes, and particularly preferably 0.2 to 8 g/10 minutes. If a styrene-based elastomer having a melt flow rate of less than 0.1 g/10 minutes or more than 10 g/10 minutes is used, the compatibility of the styrene-based elastomers when using a plurality of styrene-based elastomers decreases, the film-forming property deteriorates, and the film-forming property deteriorates. Due to the deterioration of the appearance of the film, the film may not exhibit sufficient performance.

Examples of commercially available styrene elastomers include Tufprene A, Tufprene 125, Asaprene T-438, Asaprene T-439, Tuftec H1221, Tuftec H1041, Tuftec H1052, Tuftec H1053, Tuftec H1062, Tuftec H1521, Tuftec H1517, and Tuftec P1083. , Tuftec P5051 (manufactured by Asahi Kasei Corporation), Septon 4099, Septon HG252, Septon 8004, Septon 8006, Septon 8007L, Septon HG252, Septon V9461, Septon V9475, Hibler 7311, Hibler 7125F, Hibler 5127, Hibler 5125 (above, Kuraray DYNARON 1320P, DYNARON 4600P, DYNARON 8300P, DYNARON 8903P, DYNARON 9901P (manufactured by JSR Corporation) and the like.

Commercially available styrene elastomers having a styrene component content of 14% by mass or more and 60% by mass or less among the above styrene elastomers include, for example, Tuftec H1041, Tuftec H1052, Tuftec H1053, Tuftec H1062, and Tuftec H1521. , Tuftec H1517, Tuftec P1083, Tuftec P5051 (manufactured by Asahi Kasei Corporation), Septon 8007L, Septon HG252, Hybler 5125 (manufactured by Kuraray Co., Ltd.), Dynaron 4600P, Dynaron 8903P, Dynaron 9901P (manufactured by JSR Corporation), etc. mentioned.

As the styrene-based elastomer, one type of elastomer may be used alone, or two or more types may be used in combination. It can be appropriately selected according to need, taking into account the film formability in obtaining the film, the flexibility, handleability and expandability of the thermoplastic resin film to be obtained. It is more preferable to use two or more types of styrene-based elastomers in combination from the viewpoint of the film formability of the thermoplastic resin film and the performance of the resulting film.
When two or more types are used in combination, at least one of the styrene elastomers preferably has a styrene component content of 35% by mass or more and 60% by mass or less. By using it together with a styrene component having a content within the range of 35% by mass or more and 60% by mass or less, it is possible to impart appropriate rigidity to the film without impairing the expandability, and handling of the resulting film. It is possible to improve the performance. The content of the styrene component is more preferably in the range of 37% by mass or more and 60% by mass or less, and still more preferably in the range of 39% by mass or more and 60% by mass or less.

<Other resins>
Polypropylene-based resins, polyethylene-based resins, olefin-based elastomers, cyclic olefin-based resins, polymethylpentene-based resins, and the like can be added to each layer of the thermoplastic resin film of the present invention within a range that does not impair the performance of the film. . However, the flexibility, restorability, and expandability of the obtained film may be deteriorated, so it is preferable not to add the resin or to add a small amount within a range that does not impair the performance.

<Other ingredients>
The thermoplastic resin film of the present invention has heat resistance, weather resistance, antistatic performance, etc., as components other than the styrene elastomer and other resins described above, in order to impart the performance required for the resulting film. Various additives can be blended for imparting.
Specific examples include, for example, antistatic agents, antioxidants, neutralizers, lubricants, antiblocking agents, plasticizers, heat stabilizers, light stabilizers, dyes and pigments, crystal nucleating agents, ultraviolet absorbers, fillers, Inorganic fillers that impart rigidity and elastomers other than those mentioned above for imparting flexibility may be used as long as the effects of the present invention are not impaired.
Moreover, when it is necessary to impart different performance to each layer of the film, it is possible to impart various additives having different performance to each layer.

As the antistatic agent, a known one can be used, but compatibility with the obtained thermoplastic resin film, imparting long-term antistatic performance, suppression of bleeding out of the antistatic agent over time, etc. From a viewpoint, it is preferable to use a polymeric antistatic agent.

A known polymeric antistatic agent can be used, and for example, a block copolymer of a hydrophobic block and a hydrophilic block can be used. In the polymer-type antistatic agent, a hydrophobic block and a hydrophilic block form a block copolymer through an ester bond, an ether bond, an amide bond, an imide bond, a urethane bond, a urea bond, or the like.

Hydrophobic blocks include, for example, polyolefin blocks, and polyolefin blocks include blocks made of polyethylene, polypropylene, ethylene-propylene copolymers, and the like.

Hydrophobic blocks such as polyolefin blocks have polar groups such as carbonyl groups, hydroxyl groups and amino groups at both ends. The polar groups that the hydrophobic block has at both ends are polymerized with the carbonyl groups, hydroxyl groups, amino groups, etc. present at both ends of the hydrophilic block, or crosslinked with diisocyanate, diglycidyl ether, etc. Thereby, a block copolymer of a hydrophobic block and a hydrophilic block can be obtained.

Hydrophilic blocks can include, for example, polyether blocks, polyether-containing hydrophilic polymer blocks, cationic polymer blocks and anionic polymer blocks.
In addition, in order to further improve the antistatic property, the polymer type antistatic agent may include an alkali metal or alkaline earth metal salt, a quaternary ammonium salt, a surfactant and an ionic A liquid or the like may be blended.

Examples of commercially available polyether-polyolefin block copolymers, which are one of high-molecular-weight antistatic agents, include Perestat 300, Perestat 230, Pelestat UC, Pelektron PVL, and Pelektron PVH (manufactured by Sanyo Chemical Industries, Ltd.). ) and the like.

As the ultraviolet absorber, known ones can be used, and examples thereof include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

As the light stabilizer, a known one can be used, and examples thereof include hindered amine light stabilizers.

Known substances such as organic particles, inorganic particles, and amide compounds can be used as lubricants and antiblocking agents. In addition, since it has excellent compatibility with the above-mentioned polyolefin resin, it is possible to impart defects due to bleeding out to the surface of the obtained film and long-term scratch resistance and slipperiness. is preferably used.

<Thermoplastic resin film>
The thermoplastic resin film of the present invention is composed of two or more layers, the thermoplastic resin constituting each layer contains a styrene elastomer, and the styrene elastomer contained in the front and back layers has a styrene component content of 14% by mass. It is characterized by being more than 60 mass % or less.

In order to impart flexibility, resilience and expandability to the resulting thermoplastic resin film, it is necessary to add a styrene-based elastomer to all layers constituting the film. Further, as described in the section of styrene elastomer, by using a styrene elastomer (A) (that is, a styrene elastomer having a styrene component content of 14% by mass or more and 60% by mass or less) for the front and back layers, The front and back layers of the film do not become too soft, and sticking to rolls or the like during transport of the film can be suppressed, making it easier to obtain the film.
In this specification, the front and back layers refer to the outermost layers in the layer structure of the thermoplastic resin film of the present invention.

In the thermoplastic resin film of the present invention, it is necessary to add a styrene elastomer to all of the layers constituting the thermoplastic resin film, but it is more preferable that the thermoplastic resin constituting each layer consists only of a styrene elastomer. . By forming the film only from a styrene-based elastomer, it is possible to improve flexibility, restorability, and expandability of the film.

Further, in the thermoplastic resin film of the present invention, it is more preferable that the thermoplastic resin constituting the front and back layers consists of only the styrene-based elastomer (A). This makes it possible to adjust the flexibility of the film and prevent the film from sticking to rolls or the like during transportation.
For the layers other than the front and back layers, the type of styrene elastomer used is not particularly limited, and can be appropriately selected from the styrene elastomers described above. It is more preferable to add a styrene elastomer (A). Further, the thermoplastic resin and resin composition having the same structure as the layers located in the front and back layers may be used.

The thermoplastic resin film of the present invention may be a multi-layer film consisting of two or more layers.
Here, the layer located in the middle of the multilayer film means a so-called intermediate layer when the multilayer film consists of, for example, three layers, but when the multilayer film consists of four or more layers, only the middle layer Instead, the layers before and after it are also included. For example, when the multilayer film consists of 4 layers, the "layer located in the middle of the multilayer film" includes the second and third layers counting from the surface layer, and when the multilayer film consists of 5 layers In addition to the third layer counted from the surface layer, the second and fourth layers from the surface are also included in the "layer located in the middle of the multilayer film".
As a specific configuration of the present multilayer film, for example, two kinds of two layers in which the layer containing the styrene elastomer (A) is used as the front and back layers, or a substantially single layer in which the front and back layers have the same composition, but one Seed 2-layer configuration, layer containing styrene elastomer (A) as front and back layers, and further 1-kind 3-layer or 2-kind 3-layer configuration having an intermediate layer composed of the same composition as or different from the front and back layers, styrene-based A structure of three types of three layers in which the front and back layers contain the elastomer (A) but have different resin compositions on the front and back and an intermediate layer with a different composition, and the resin composition on the front and back is different, but the intermediate layer A multi-layer film having a two-kind three-layer structure, which is substantially one-kind and two-layer, which has the same composition as the above composition, and a multi-layered structure having more than that.
From the viewpoint of ease of film formation and handling of equipment, it is preferable to have a 2-kind 2-layer, 2-kind 3-layer, 3-kind 3-layer, substantially single layer 1-kind 2-layer or 1-kind 3-layer structure. preferable.

In addition, the content of the styrene elastomer (A) in the resin composition constituting the front and back layers of the present multilayer film is the thermoplastic resin constituting the resin composition, as described above in the section on the styrene elastomer. Among 100% by mass, it is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 70% by mass or more and 100% by mass or less.
Further, as the styrene elastomer contained in all layers including the front and back layers, even when two or more types are used in combination, at least one of the styrene elastomers has a styrene component content of 35% by mass or more and 60% by mass, as described above. It is preferable to make it into the range below mass %. By using together with a styrene component having a content of 35% by mass or more and 60% by mass or less, it is possible to impart appropriate rigidity to the film without impairing the expandability, and handling of the resulting film. It is possible to improve the performance. The content of the styrene component is more preferably in the range of 37% by mass or more and 60% by mass or less, and still more preferably in the range of 39% by mass or more and 60% by mass or less.

Moreover, the total thickness of the thermoplastic resin film of the present invention is preferably 30 to 250 μm. If the total thickness of the film is 30 μm or more, the film formability and handleability of the resulting film will be good, and if it is 250 μm or less, it will be economical and pass through processes such as adhesive processing using the film. It is possible to maintain good properties. Further, from the viewpoint of economy and expandability, it is more preferably within the range of 30 to 200 μm, further preferably within the range of 30 to 150 μm.

Further, the tensile modulus of the thermoplastic resin film of the present invention is preferably in the range of 50-1500 MPa. If the tensile modulus of elasticity of the film is 50 MPa or more, sufficient rigidity is imparted to the film, so that it is possible to maintain good handleability. It is possible to keep good workability of the film, and to make the load applied to the film and the device at the time of expansion appropriate. More preferably from 50 to 1000 MPa, still more preferably from 50 to 500 MPa.

Further, the expandability of the thermoplastic resin film of the present invention can be measured using a wafer expansion device manufactured by Hugle Electronics. Moreover, it is preferable to use the adhesive film after laminating|stacking the adhesive layer in order to confirm the influence of the adhesive layer laminated|stacked on a thermoplastic resin film. The adhesive film will be described later.

The ring size, push-up speed, push-up amount, and stage temperature for the expansion test should be set as long as the size of the wafer, the prevention of tearing and tearing of the film during expansion, and the spacing between chips are sufficient. , can be set arbitrarily.

As a method for molding the thermoplastic resin film of the present invention, a known method can be used, but a melt extrusion molding method is preferably used. Among the melt extrusion molding methods, a T-die molding method in which a molten resin is extruded from an extruder having a T-die and solidified by cooling to obtain a film is more preferable.

In order to obtain a film, it is preferable to adopt a co-extrusion T-die molding method using a plurality of extruders. A multi-layered film can be obtained by using a co-extrusion T-die molding method using a plurality of extruders.
Further, by extruding the same resin from all extruders, it is possible to obtain a substantially monolayer film in which all layers are made of the same resin composition.

As a coextrusion T die molding method, a multi-manifold die is used to form a plurality of resin layers into a film, and then they are brought into contact in the T die to form multiple layers to obtain a film. A method of obtaining a multilayer film after merging and adhering a plurality of resins using an apparatus for merging the resins.

The film may optionally be surface-treated on one or both sides by methods such as plasma treatment, corona treatment, ozone treatment and flame treatment. Depending on the intended use of the film to be obtained, it is possible to select whether to surface-treat one side or both sides.

<Adhesive film>
By laminating an adhesive layer on at least one side of the thermoplastic resin film of the present invention, an adhesive film can be obtained (hereinafter also referred to as "adhesive film of the present invention").

The adhesive used for the adhesive layer is not particularly limited, but various adhesives such as natural rubber resins, acrylic resins, styrene resins, silicone resins, and polyvinyl ether resins are used. Further, a functional layer such as an adhesive layer or a thermosetting resin layer may be provided on the adhesive layer.

In the pressure-sensitive adhesive film of the present invention, one side or both sides of the film before laminating the pressure-sensitive adhesive layer may be subjected to the surface treatment described above. A primer layer may be provided between the substrate film and the adhesive layer, if necessary.
The thickness of the adhesive layer and the primer layer can be appropriately determined according to need.

Since the pressure-sensitive adhesive film of the present invention uses a film that is excellent in flexibility, resilience, and expandability, it can be suitably used in semiconductor manufacturing processes.

Examples and comparative examples of the present invention will be shown and described below in detail, but the present invention is not limited to these examples. The materials used in the following examples and comparative examples, the methods for measuring the properties evaluated, etc. are as follows.

<Styrene-based elastomer>
Styrene-based elastomer (A-1):
JSR Corporation, "Dynaron 4600P" (melt flow rate at 230 ° C., 2.16 kg: 5.5 g / 10 minutes, content of styrene component: 20% by mass, styrene-ethylene-butylene-crystalline olefin copolymer)
Styrene-based elastomer (A-2):
Asahi Kasei Corporation, "Tuftec H1041" (melt flow rate at 230 ° C., 2.16 kg: 5.0 g / 10 minutes, content of styrene component: 30% by mass, styrene-ethylene/butylene-styrene copolymer)
Styrene-based elastomer (A-3)
Asahi Kasei Corporation, "Tuftec P5051" (melt flow rate at 190 ° C., 2.16 kg: 3.0 g / 10 minutes, content of styrene component: 47% by mass, styrene-ethylene/butylene-styrene copolymer)
Styrene-based elastomer (B):
Asahi Kasei Corporation, "Tuftec H1221" (melt flow rate at 230 ° C., 2.16 kg: 4.5 g / 10 minutes, content of styrene component: 12% by mass, styrene-ethylene/butylene-styrene copolymer)

<Preparation of resin composition>
The above styrene-based elastomers were blended to a total of 100 parts by mass and mixed by dry blending. It was visually confirmed that the mixture was uniformly mixed, and a resin composition for film molding was prepared for each of the surface layer, the intermediate layer, and the back layer.

<Film forming method>
Each hopper of three single-screw extruders manufactured by Toshiba Machine (for surface layer: 35 φ mm, L / D = 25 mm, for intermediate layer: 50 φ mm, L / D = 32, for back layer: 35 φ mm, L / D = 25 mm) The dry blended raw material is put in, the extruder temperature of each extruder is set to 190 to 240 ° C., and the three-layer structure of the surface layer / intermediate layer / back layer is combined at the feed block section, and a 650 mm wide T die (Temperature setting: 230°C, lip opening: 0.5 mm). For the thickness configuration, each extruder rotation speed was set so as to achieve the thicknesses shown in Table 1.

The extruded molten resin is cooled and solidified by a winder equipped with a mat-shaped metal cooling roll (cooling roll 700mm width x φ350mm, roll temperature about 30°C), then corona-treated on both sides and wound up. was carried out to obtain a multi-layered film of two kinds and three layers or three kinds and three layers having a predetermined thickness.
Further, in the present invention, the surface of the obtained film on the cooling roll side is expressed as the surface layer.

[Thickness of each layer]
The thickness of each layer was set by calculation from the amount of resin extruded from each extruder. Moreover, from the result of cross-sectional observation of the obtained film, it was confirmed that the thickness was as set.

[Total thickness of film]
Using a contact-type thickness meter, the thickness of the film was measured at the central portion and both ends, and it was confirmed that the film had a predetermined thickness.

[Film formability]
The thickness stability and handleability of the film produced by the film-forming method described above were evaluated according to the following criteria.
○: Easy to handle, no sticking to the roll △: Slight sticking to the transport roll, but film formation possible ×: Highly flexible and difficult to handle, and not sticking to the transport roll Sticking

[Tensile modulus]
From the resulting multilayer film, a dumbbell "SDK-600" manufactured according to JISK6732 is used to collect a test piece, and with reference to JISK7127, an autograph (Shimadzu The tensile modulus (MPa) was measured at a tensile speed of 50 mm/min using AGS-X manufactured by Seisakusho.
The tensile modulus was measured in the extrusion direction (MD) of the film.

[Tensile breaking elongation]
From the obtained multilayer film, a test piece was collected using a dumbbell "SDK-600" manufactured according to JISK6732, and a small desktop tester (EZ -L) was used to measure the tensile elongation at break (%) at a tensile speed of 300 mm/min.
The tensile elongation at break was measured in the extrusion direction (MD) of the film.

[Restoration]
A test piece was taken from the obtained multilayer film using a dumbbell "SDK-600" manufactured according to JISK6732, and a 40 mm mark was drawn in the center of the test piece. Using an autograph (AGS-X manufactured by Shimadzu Corporation), the test piece with the marked lines is stretched at a tensile speed of 200 mm / min in an atmosphere of 23 ° C. and 50% RH, and the distance between the marked lines becomes 60 mm. The test piece was stretched and held in the stretched state for 1 minute.
After holding, the test piece was removed, and the restorability after standing for 5 minutes was calculated by the following formula.

[Expandability]
During the restorability test described above, the state of the test piece when stretched was visually observed and evaluated according to the following criteria.
◯: Uniformly stretched and good expandability ×: The test piece was not stretched uniformly and necking was observed.

[Example 1]
Styrene-based elastomer (A-1) and styrene-based elastomer (A-3) as surface layer resins, and styrene-based elastomer (A-1), styrene-based elastomer (A-2) and styrene-based resins as intermediate layer resins Elastomer (A-3), styrene-based elastomer (A-1) and styrene-based elastomer (A-3) were used as the resin for the back layer at the content shown in Table 1, and two types were obtained by the above-described film-forming method. A 150 μm thick film consisting of three layers was obtained. The thickness of each layer was 15 μm for the surface layer, 120 μm for the intermediate layer and 15 μm for the back layer, and the thickness ratio was 10% for the surface layer, 80% for the intermediate layer and 10% for the back layer.
The film had good film-forming properties without any observed sticking to transport rolls or the like during molding. The film was not too flexible and was excellent in handleability.
The resulting film had a tensile modulus of 100 MPa, and was confirmed to have sufficient rigidity for handleability. It is assumed that the possibility of occurrence is low.
The film had a good recovery property of 92%, and it was confirmed that the test piece was uniformly stretched during the test, so it is presumed that the expandability is also excellent.
Next, an acrylic adhesive is applied on the separator by a comma coating method so that the thickness of the adhesive layer after drying is 25 μm, dried for 5 minutes in a hot air dryer at 80 ° C., and then adhesive. formed a layer. It was possible to obtain an adhesive film in which the film of the present invention and the adhesive layer are laminated by laminating the adhesive layer side surface of the prepared separator to the chill roll side surface of the film.

[Comparative Example 1]
Styrene-based elastomer (B) as the resin for the surface layer, styrene-based elastomer (A-2), styrene-based elastomer (A-3) and styrene-based elastomer (B) as the resin for the intermediate layer, and resin for the back layer Using the styrene-based elastomer (B) in the content shown in Table 1, the film-forming method described above was used to form a film having a thickness of 150 µm consisting of three layers of two types, each layer having a thickness of 15 µm for the surface layer, a thickness of 120 µm for the intermediate layer, and a back layer. was 15 μm.
Since the front and back layers of this film were styrene-based elastomer (B) with a styrene component content of less than 14% by mass, sticking to transport rolls, etc., during molding was remarkable, making it difficult to obtain a film. Furthermore, since the content of the styrene-based elastomer with a low styrene component content was high and the material was flexible, it was difficult to handle. Therefore, a film for evaluation could not be obtained.

[Industrial applicability]
INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a film that is excellent in film-forming properties when molding a resin into a film, and that is also excellent in flexibility, resilience, and expandability. Moreover, since it is excellent in flexibility, resilience, and expandability, it is possible to provide an adhesive film for semiconductor manufacturing processes capable of ensuring sufficient spacing between chips.

Claims (7)

A thermoplastic resin film consisting of two or more layers,
The thermoplastic resin comprising each layer contains a styrene elastomer, and the content of the styrene component in the styrene elastomer contained in the front and back layers is 14% by mass or more and 60% by mass or less. resin film. 2. The thermoplastic resin film according to claim 1, wherein the thermoplastic resin constituting each layer consists only of a styrene-based elastomer. 3. The thermoplastic resin film according to claim 1, wherein the thermoplastic resin constituting the front and back layers consists only of a styrene-based elastomer having a styrene content of 14% by mass or more and 60% by mass or less. The heat according to any one of claims 1 to 3, wherein the styrene elastomer is a block copolymer of a vinyl aromatic compound and a conjugated diene compound, a hydrogenated product thereof, or a mixture thereof. plastic resin film. 5. The thermoplastic resin film according to any one of claims 1 to 4, which comprises a surface layer/intermediate layer/back layer comprising two kinds of three layers or three kinds of three layers. An adhesive film obtained by providing an adhesive layer on at least one surface of the thermoplastic resin film according to any one of claims 1 to 5. The pressure-sensitive adhesive film for a semiconductor manufacturing process according to claim 6, which is used in a semiconductor manufacturing process.