JP2023034236A - 4-methyl-1-pentene (co)polymer-containing film, and production method and use thereof - Google Patents

Abstract

To provide a 4-methyl-1-pentene (co)polymer film, which is a film that realizes excellent mold releasability derived from 4-methyl-1-pentene (co)polymer, that is a mono-material suitable for material recycling, and in which wrinkles are suppressed to a sufficient level as a mold release film.SOLUTION: Provided is a film containing 4-methyl-1-pentene (co)polymer by 90 mass% or more in which the thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C is 3% or less, and the sum of the thermal dimensional change rate from 23°C to 150°C in the transverse (TD) direction and the thermal dimensional change rate from 23°C to 150°C in the longitudinal (MD) direction is 6% or less.SELECTED DRAWING: None

Description

The present invention relates to a film containing a 4-methyl-1-pentene (co)polymer. It relates to a film containing a 4-methyl-1-pentene (co)polymer, which can be particularly preferably used as.

In recent years, from the viewpoint of environmental protection, resource saving, and the like, recycling of plastic materials such as 4-methyl-1-pentene (co)polymer, preferably material recycling, has been demanded. 4-Methyl-1-pentene (co)polymer film is mainly used for release films, etc., which are used in limited areas such as factories, so they are easy to collect after use, and material recycling is implemented. It's easy to do.
By the way, if the release film used in the semiconductor encapsulation process or the like has a large thermal expansion, wrinkles will occur, so it is important to suppress the thermal expansion. For the purpose of suppressing thermal expansion, etc., stretched polyester film, etc., with a three-layer structure of 4-methyl-1-pentene (co)polymer layer / heat-resistant resin layer / 4-methyl-1-pentene (co)polymer layer is proposed for use in the heat-resistant resin layer (see, for example, Patent Document 1). However, since the film having such a structure is not a monomaterial, it is difficult to recycle the material.

In the above configuration, if only the 4-methyl-1-pentene (co)polymer layer is used as a single layer film, it is a monomaterial, so it is suitable for material recycling, and is derived from the 4-methyl-1-pentene (co)polymer. Excellent releasability can be achieved. However, since the 4-methyl-1-pentene (co)polymer layer is not stretched, it is likely to wrinkle when made into a single layer film, and is used as a release film, especially a release film in a molding process involving heating. As a result, wrinkles may adversely affect the appearance of the molded product.
As a means of suppressing wrinkles in a polymer film, it is generally considered effective to appropriately stretch the polymer film. However, 4-methyl-1-pentene (co)polymer film is inferior in stretching processability, such as uneven stretching, breakage, and cracking, and various stretching methods and stretching stocks have been proposed to solve this problem. (see, for example, Patent Documents 2 and 3), even with these methods, it is not always easy to perform uniform stretching without breakage or cracking, and wrinkles are not caused at a sufficient level as a release film. could not be restrained.

JP 2017-100397 A JP-A-61-228931 JP 2011-088339 A

The present invention has been made in view of the above-mentioned limitations of the prior art, and is a film that achieves excellent releasability derived from 4-methyl-1-pentene (co)polymer, and is suitable for material recycling. It is an object of the present invention to provide a film containing a 4-methyl-1-pentene (co)polymer, which is a suitable monomaterial and has wrinkles suppressed to a sufficient level as a release film.

The inventors of the present invention have made intensive studies to solve the above problems, and found that a film containing a predetermined amount of 4-methyl-1-pentene (co)polymer can be and the sum of the thermal dimensional change rate from 23°C to 150°C in the transverse (TD) direction and the thermal dimensional change rate from 23°C to 150°C in the longitudinal (MD) direction is a predetermined value. The inventors have found that the following film achieves releasability, mono-material, and wrinkle suppression at a level exceeding that of the prior art, and can solve the time-related problems, leading to the completion of the present invention.
That is, the present invention and its respective aspects are as described in [1] to [8] below.

[1]
The thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C is 3% or less, and the thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C and the longitudinal (MD) direction at 23°C A film containing 90% by mass or more of a 4-methyl-1-pentene (co)polymer having a sum of 6% or less of thermal dimensional change from temperature to 150°C.
[2]
The film of [1], wherein the film is a monolayer film.
[3]
Both the longitudinal (MD) direction and transverse (TD) direction draw ratios are 1.01 times or more, and the area ratio represented by the longitudinal (MD) direction draw ratio × transverse (TD) direction draw ratio is The film according to [1] or [2], which is a biaxially stretched film of 1.02 to 2.00 times.
[4]
The film according to any one of [1] to [3], wherein the thermal dimensional change rate from 23° C. to 150° C. in the transverse (TD) direction is 0% or more.
[5]
The method for producing a film according to any one of [1] to [4], comprising a step of biaxially stretching a raw film containing 90% by mass or more of a 4-methyl-1-pentene (co)polymer. The above production method, wherein the biaxial stretching is carried out at a temperature of 50° C. or higher and lower than the melting point of the 4-methyl-1-pentene (co)polymer.
[6]
After the step of biaxially stretching, further comprising a step of performing a heat setting treatment at a temperature equal to or higher than the temperature of the biaxial stretching and lower than the melting point of the 4-methyl-1-pentene (co)polymer [5] The manufacturing method described in .
[7]
The film according to any one of [1] to [4], which is a release film.
[8]
The film according to any one of [1] to [4], which is a release film for a semiconductor encapsulation process.

The film of the present invention achieves technical effects beyond the limits of the prior art, such as high levels of releasability, recyclability, and anti-wrinkle performance. When the film of the present invention is used, for example, as a release film for semiconductor encapsulation, a molded article obtained by encapsulating a semiconductor chip or the like with a resin can be easily released from the mold, and the molded article does not have appearance defects such as wrinkles. can be produced with high productivity, and the release film can be material-recycled.

FIG. 3 is a schematic diagram illustrating a wrinkle evaluation method in one example of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the manufacturing method of the resin-sealed semiconductor using the film of this invention.

In the present invention, the thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction is 3% or less, and the thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction and the longitudinal (MD) A film containing 90% by mass or more of a 4-methyl-1-pentene (co)polymer, the sum of thermal dimensional change rates from 23°C to 150°C in the direction being 6% or less.
Here, the transverse (TD) direction means a direction in the plane of the film that is perpendicular to the longitudinal direction of the film during manufacture, and is hereinafter simply referred to as the "lateral direction" and the "TD direction". Further, the machine direction (MD) refers to the longitudinal direction of the film during production, and is hereinafter simply referred to as the "longitudinal direction" and the "MD direction".
Since the film of the present invention contains 90% by mass or more of 4-methyl-1-pentene (co)polymer, it is substantially a monomaterial, excellent in recyclability, and material recycling is possible. The film of the present invention can be preferably used as a release film used in the manufacturing process, but since such a release film is used in factories where the manufacturing process is performed, it is relatively easy to collect after use. is. Therefore, being excellent in recyclability is particularly significant in terms of economy and environment.
From the viewpoint of recyclability, the film of the present invention preferably contains 95% by mass or more of the 4-methyl-1-pentene (co)polymer, particularly preferably 98% by mass or more.
The film of the present invention may be composed only of a 4-methyl-1-pentene (co)polymer, but within a range that does not impair the object of the present invention, particularly recyclability, and 4-methyl-1-pentene It may contain other components as long as it does not violate the requirement that the (co)polymer be contained in an amount of 90% by mass or more.

4-methyl-1-pentene (co)polymer

The 4-methyl-1-pentene (co)polymer used in the film of the present invention may be a homopolymer of 4-methyl-1-pentene, or 4-methyl-1-pentene and olefins, preferably α-olefins having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene; the same shall apply hereinafter).

In the case of a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms, the olefin having 2 to 20 carbon atoms to be copolymerized with 4-methyl-1-pentene is 4 - can impart flexibility to methyl-1-pentene. Examples of α-olefins having 2 to 20 carbon atoms are ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene. , 1-octadecene, 1-eicosene and the like. These olefins may be used alone or in combination of two or more.

In the case of a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms, the proportion of constituent units derived from 4-methyl-1-pentene is 96% by mass or more, and It is preferable that the proportion of structural units derived from olefins having 2 to 20 carbon atoms other than is 4% by mass or less. By reducing the content of structural units derived from α-olefins having 2 to 20 carbon atoms, the copolymer can be hardened, that is, the storage elastic modulus E' can be increased, and wrinkles occur during the sealing process, etc. It is advantageous for suppression of On the other hand, by increasing the content of structural units derived from α-olefins having 2 to 20 carbon atoms, the copolymer can be softened, that is, the storage elastic modulus E' can be lowered, and the mold followability etc. can be improved. useful for improving
The proportion of structural units derived from 4-methyl-1-pentene is more preferably 96 to 99% by mass, and the proportion of structural units derived from other olefins having 2 to 20 carbon atoms is 4 to 1% by weight is particularly preferred.

The 4-methyl-1-pentene (co)polymer may have a structural unit derived from a copolymer component other than the α-olefin having 2 to 20 carbon atoms. Copolymerization components other than α-olefins having 2 to 20 carbon atoms include, for example, α-olefins having more than 20 carbon atoms, cyclic olefins, aromatic vinyl compounds, conjugated dienes, non-conjugated polyenes, functional vinyl compounds, and hydroxyl groups. Containing olefins and halogenated olefins. Examples of cyclic olefins, aromatic vinyl compounds, conjugated dienes, non-conjugated polyenes, functional vinyl compounds, hydroxyl group-containing olefins and halogenated olefins include compounds described in paragraphs [0035] to [0041] of JP-A-2013-169685. can be mentioned. These copolymer components other than α-olefins having 2 to 20 carbon atoms may be used alone or in combination of two or more.

The 4-methyl-1-pentene (co)polymer can be produced by methods known to those skilled in the art. For example, it can be produced by a method using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts. The 4-methyl-1-pentene (co)polymer is preferably a highly crystalline (co)polymer. The crystalline copolymer may be either a copolymer having an isotactic structure or a copolymer having a syndiotactic structure. In particular, it should be a copolymer having an isotactic structure. is preferable from the viewpoint of physical properties and is easily available. Furthermore, the 4-methyl-1-pentene (co)polymer can be molded into a film, and if it has strength to withstand the temperature and pressure during mold molding, the stereoregularity and molecular weight are also limited. not. The 4-methyl-1-pentene copolymer may be a commercially available copolymer such as TPX (registered trademark) manufactured by Mitsui Chemicals, Inc.

As described above, the film of the present invention may be composed only of 4-methyl-1-pentene (co)polymer, and 4 -Methyl-1-pentene (co)polymer may be contained in an amount of 90% by mass or more, so long as it does not violate the requirement, other components may be contained.
Other components are not particularly limited, and additives such as stretching aids conventionally used in films made of 4-methyl-1-pentene (co)polymer or similar materials, and 4-methyl- Various resins other than the 1-pentene (co)polymer may be contained.
Preferred examples of stretching aids include petroleum resins and terpene resins.
Other additives include weather stabilizers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, nucleating agents, lubricants, pigments, dyes, Antiaging agents, hydrochloric acid absorbents, inorganic or organic fillers, organic or inorganic foaming agents, cross-linking agents, cross-linking aids, adhesives, softening agents, flame retardants and the like can be mentioned.
Resins other than 4-methyl-1-pentene (co)polymers include thermoplastic polyolefin resins other than 4-methyl-1-pentene (co)polymers, thermoplastic polyamide resins, thermoplastic polyester resins, Examples include thermoplastic resins such as thermoplastic vinyl aromatic resins, and thermosetting resins such as unsaturated polyester resins, epoxy resins, phenol resins, urea resins, melamine resins, diallyl phthalate resins, and silicone resins. can.
These other components may also be used alone or in combination of two or more.

The film of the present invention is preferably a single-layer film from the viewpoint of recyclability, production cost, etc. However, the requirements of the present invention, particularly the 4-methyl-1-pentene (co)polymer content of 90% by mass or more, is preferable. It does not exclude a multilayer film (laminate) as long as it satisfies the requirement of "including". In the case of a multilayer film, it contains 90% by mass or more of the 4-methyl-1-pentene (co)polymer based on the total mass of the multilayer film.
In the case of a multilayer film, all layers may contain 4-methyl-1-pentene (co)polymer, and only some of the layers may contain 4-methyl-1-pentene (co)polymer. ) polymer, but since it contains 90% by mass or more of 4-methyl-1-pentene (co)polymer based on the mass of the entire multilayer film, 4-methyl-1-pentene (co ) At least one layer containing a polymer dominates the multilayer film.

When the multilayer film has a layer other than the layer containing the 4-methyl-1-pentene (co)polymer (hereinafter also referred to as "other layer"), the other layer may be, for example, a matte layer (surface unevenness layer), a release layer, a conductive layer, an antistatic layer, an optical coating layer, an adhesive layer, an adhesive layer, a gas barrier layer, and the like, but are not limited to these.

Although the thickness of the film of the present invention is not particularly limited, it is preferably 10 to 300 μm, more preferably 30 to 150 μm. When the thickness of the film of the present invention is within the above range, it is preferable because the handling property when used as a roll is good and the amount of waste of the film is small.
When the film of the present invention is a multilayer film, the thickness of the layer containing the 4-methyl-1-pentene (co)polymer is also preferably 10 to 300 μm, more preferably 30 to 150 μm.

Thermal dimensional change rate of film In the present invention, in order to solve the above problems of the invention, a film containing a predetermined amount or more of 4-methyl-1-pentene (co)polymer, is a predetermined value or less, and the sum of the thermal dimensional change rate in the transverse (TD) direction and the thermal dimensional change rate in the longitudinal (MD) direction is a predetermined value or less. be.
That is, in the film of the present invention, the thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C is 3% or less, and the thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C is 3% or less. and the sum of the thermal dimensional change rate from 23° C. to 150° C. in the machine direction (MD) is 6% or less.
In the film of the present invention, the thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction is 3% or less, and the thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction and the longitudinal Since the sum of the thermal dimensional change rates from 23 ° C. to 150 ° C. in the (MD) direction is 6% or less, the occurrence of wrinkles during heating can be effectively suppressed. When used as a release film, it is possible to produce a molded article obtained by sealing a semiconductor chip or the like with a resin, with a good appearance.

The thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction and the thermal dimensional change rate from 23 ° C. to 150 ° C. in the longitudinal (MD) direction in the film of the present invention are, respectively, the lateral (TD) direction And in the longitudinal (MD) direction, after holding at 23 ° C. for 5 minutes with a load of 0.005 N, the temperature was increased from 23 ° C. to 150 ° C. at a temperature increase rate of 10 ° C./min, and measured at 23 ° C. is the thermal dimensional change rate calculated from the sample length at 150° C. and the sample length at 150° C.
More specifically, a film sample cut into an appropriate size is subjected to a load of 0.005 N in the measurement direction (transverse (TD) direction or longitudinal (MD) direction) using a thermomechanical analyzer. After holding at 23°C for 5 minutes, the temperature was raised from 23°C to 150°C at a heating rate of 10°C/min, and the sample length (distance between load points) at 23°C and 150°C in the measurement direction was measured. , the thermal dimensional change rate is calculated by the following formula (1).
Thermal dimensional change rate (%) (23→150° C.) = {[(L ₂ −L ₁ )/L ₁ ]×100}
... (1)
L ₁ : Sample length (mm) at 23°C
_L2 : Sample length (mm) at 150°C
As long as the above conditions are followed, there are no particular restrictions on the details of the measurement method such as the device and operation used for measurement, and the measurement can be performed as appropriate by a method commonly used in the art. It is preferable to measure by the method of

Wrinkles are generated when the thermal dimensional change rate in the lateral (TD) direction and the sum of the thermal dimensional change rate in the lateral (TD) direction and the thermal dimensional change rate in the longitudinal (MD) direction are each less than a predetermined value. Although the mechanism by which this is suppressed is not necessarily clear, by using a film with relatively small thermal expansion/shrinkage, uneven thermal expansion/shrinkage on the film surface due to heating/cooling during the process can be suppressed, and some presumed to be related.

From the viewpoint of more effectively suppressing the occurrence of wrinkles, the film of the present invention should have a thermal dimensional change rate of 2.5% or less from 23° C. to 150° C. in the TD direction (transverse direction). It is preferably 2.0% or less, more preferably 1.5% or less. On the other hand, the film of the present invention has a thermal dimensional change rate from 23° C. to 150° C. in the TD direction (transverse direction) of 0% or more, preferably more than 0%, from the viewpoint of preventing adsorption errors. preferable.

From the viewpoint of more effectively suppressing the occurrence of wrinkles, the film of the present invention has a thermal dimensional change rate from 23°C to 150°C in the transverse (TD) direction and a The sum of the thermal dimensional change rates up to °C is preferably 5.0% or less, particularly preferably 4.5% or less.
The sum of the thermal dimensional change rate from 23°C to 150°C in the transverse (TD) direction and the thermal dimensional change rate from 23°C to 150°C in the longitudinal (MD) direction is preferably -2% or more. , -1% or more, and particularly preferably 0% or more.

In the film of the present invention, the thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction is 3% or less, and the thermal dimensional change rate from 23 ° C. to 150 ° C. in the transverse (TD) direction and the longitudinal As long as the sum of the thermal dimensional change rates in the (MD) direction from 23 ° C. to 150 ° C. is 6% or less, the thermal dimensional change in the longitudinal (MD) direction from 23 ° C. to 150 ° C. Although there is no particular limitation on the ratio, it is preferably 5% or less, and 4% or less from the viewpoint of facilitating the achievement of the above conditions and more effectively suppressing the occurrence of wrinkles. is more preferred. Further, the thermal dimensional change rate from 23° C. to 150° C. in the longitudinal (MD) direction of the film of the present invention is preferably −2% or more, more preferably −1% or more, and 0% or more. is particularly preferred.

As described above, the film of the present invention may be a single-layer film or a multilayer film (laminate). It is defined and measured for the entire multilayer film.
However, from the viewpoint of realizing the above thermal dimensional change rate for the entire multilayer film, at least a part of each layer constituting the multilayer film preferably satisfies the above conditions for the thermal dimensional change rate. In some cases, it is preferred that the layer containing the 4-methyl-1-pentene (co)polymer occupying the major part thereof satisfies the above condition of the thermal dimensional change rate.
It is particularly preferable that all of the layers constituting the multilayer film satisfy the above condition of thermal dimensional change rate.

Thermal dimensional change from 23°C to 150°C in the transverse (TD) direction of the film and thermal dimensional change from 23°C to 150°C in the transverse (TD) direction and from 23°C to 150°C in the longitudinal (MD) direction The sum of the thermal dimensional change rates up to can be adjusted by appropriately changing and setting the material of the film and the manufacturing conditions.
In particular, in producing the film, stretching, preferably biaxial stretching, is performed, and the thermal dimensional change rate of the film can be appropriately adjusted by appropriately setting stretching conditions such as stretching ratio and stretching temperature. . The heat dimensional change rate of the film can also be appropriately adjusted by appropriately adopting a so-called heat setting treatment in which the stretched film is held at a predetermined temperature for a certain period of time.

Preferred Physical Properties of Film The film of the present invention can achieve excellent releasability by containing 90% by mass or more of the 4-methyl-1-pentene (co)polymer.
The degree of releasability may be appropriately set according to the purpose and form of use, and is not particularly limited, but the contact angle with water, which is often used as a measure of releasability, is usually 90° to 130°. , preferably 95° to 120°, more preferably 98° to 115°, still more preferably 100° to 110°.

By containing 90% by mass or more of 4-methyl-1-pentene (co)polymer, or by setting the content ratio to be higher than that, the above-mentioned water contact angle is often achieved, but further separation An additive (mold release agent) capable of improving the moldability may be used, or surface treatment may be performed.
There are no particular restrictions on the types of release agents that can be used, and silicone-based release agents, melamine-based release agents, polyolefin-based release agents, epoxy-based release agents, acrylic-based release agents, and fluorine-based release agents. , cellulose-based release agents, paraffin-based release agents, epoxy-melamine-based release agents, and combinations thereof.
These releasing agents may be added to the resin constituting the film of the present invention including 4-methyl-1-pentene (co)polymer, or may be applied to the film of the present invention.
Moreover, the surface of the film of the present invention may have an uneven shape as necessary, whereby the releasability can be further improved. There are no particular restrictions on the method of providing unevenness to the surface of the film, but a general method such as embossing can be used.

The film of the present invention can be suitably used as a mold release film for processing, and in this case, it preferably has heat resistance that can withstand the temperature of the mold during molding (typically 120 to 180 ° C.). . From this point of view, the 4-methyl-1-pentene (co)polymer constituting the film of the present invention is preferably crystalline, and the melting point of the 4-methyl-1-pentene (co)polymer is 190 ° C. or higher, and more preferably 200° C. or higher and 240° C. or lower.
By using a 4-methyl-1-pentene (co)polymer that is crystalline and/or has a melting point within the above range, the occurrence of wrinkles is more effectively suppressed in the resin sealing process, etc., and wrinkles are formed. It is possible to more effectively suppress phenomena such as poor appearance caused by being transferred to the product.

The resin containing the 4-methyl-1-pentene (co)polymer, which constitutes the film of the present invention, is measured by differential scanning calorimetry (DSC) according to JISK7221. is preferably 15 J/g or more and 60 J/g or less, more preferably 20 J/g or more and 50 J/g or less. When it is 15 J/g or more, it is possible to more effectively exhibit heat resistance and releasability that can withstand hot press molding in a resin sealing process, etc., and also to suppress the dimensional change rate. Therefore, the occurrence of wrinkles can be more effectively prevented. On the other hand, if the heat of crystal fusion is 60 J/g or less, the film will have an appropriate hardness, and sufficient followability of the film to the mold can be obtained in the resin sealing process, etc., and the film will not be damaged. can be suppressed more effectively.

Stretched Film The film of the present invention may be a non-stretched film, but since unstretched 4-methyl-1-pentene (co)polymer films often have a large rate of thermal dimensional change due to thermal expansion, heat From the viewpoints of appropriately controlling the dimensional change rate and controlling the hardness to an appropriate value, it is preferable to use a stretched film.
The stretched film in this embodiment may be a uniaxially stretched film or a biaxially stretched film. In the case of a uniaxially stretched film, it may be stretched longitudinally or transversely, but it is relatively easy to reduce the coefficient of thermal expansion in the transverse (TD) direction or make it negative by transverse stretching. Therefore, it is desirable that the film be stretched at least in the transverse (TD) direction.

The method and apparatus for obtaining the stretched film of the above embodiment are not particularly limited, and stretching may be performed by a method known in the art. For example, an unstretched original film can be stretched with a heating roll or a tenter type stretching machine.
The method for producing the original film is not particularly limited. For example, a raw material resin containing 90% by mass of 4-methyl-1-pentene (co)polymer is formed into a film by extrusion molding, press molding, or the like. By doing so, a raw film can be produced.
The thickness of the raw film is not particularly limited, and may be appropriately set in consideration of the application, draw ratio, etc., but it is usually 10 to 360 μm, preferably 30 to 180 μm.

There is no particular limitation on the draw ratio, and an appropriate value may be appropriately set to appropriately control the thermal dimensional change rate and achieve suitable mechanical properties. ) direction is preferably 1.01 times or more.
Either the machine direction (MD) or the transverse (TD) direction draw ratio is more preferably 1.01 to 1.50 times, particularly preferably 1.01 to 1.35 times.
Both the machine direction (MD) and transverse (TD) direction draw ratios are more preferably within the more preferable ranges described above, and even more preferably within the particularly preferable ranges described above.
When the draw ratio in either the longitudinal (MD) direction or transverse (TD) direction is 1.01 or more, the thermal dimensional change, particularly thermal expansion, of the film can be more effectively suppressed.
On the other hand, when the draw ratio in either the machine direction (MD) or the transverse direction (TD) is 1.50 or less, the heat shrinkage of the film can be more effectively suppressed. Moreover, it is easy to perform uniform stretching without breaking or cracking.

In the above embodiment, the area ratio represented by the draw ratio in the longitudinal (MD) direction×the draw ratio in the transverse (TD) direction is preferably 1.02 to 2.00 times.
When the draw ratio in the longitudinal (MD) direction×the draw ratio in the transverse (TD) direction is 1.02 or more, thermal dimensional change, particularly thermal expansion, of the film can be more effectively suppressed.
On the other hand, when the draw ratio in the longitudinal (MD) direction×the draw ratio in the transverse (TD) direction is 2.00 or less, thermal expansion can be suppressed to the extent that the film does not thermally shrink. Moreover, it is easy to perform uniform stretching without breaking or cracking.
The area ratio represented by the draw ratio in the machine direction (MD)×the draw ratio in the transverse (TD) direction is particularly preferably 1.03 times or more and less than 1.60 times.

The order of stretching in the case of biaxial stretching is not particularly limited, and either simultaneous biaxial stretching or sequential biaxial stretching may be employed.
When the sequential biaxial stretching is performed, the stretching in the longitudinal (MD) direction may be performed first, or the stretching in the transverse (TD) direction may be performed first.
There are no particular restrictions on the specific stretching method, apparatus, and the like, and methods commonly used in the art can be employed as appropriate. For example, for stretching in the machine direction (MD), it is possible to stretch using the peripheral speed difference of the rolls, etc., and for stretching in the transverse (TD) direction, it is common to stretch with a tenter. However, it can also be stretched with an expander roll or a cross guider.
From the viewpoint of productivity, it is preferable to employ the various stretching methods described above, but when the production volume is small or when performing high-mix low-volume production, batchwise stretching is also preferable.

The temperature for stretching is not particularly limited, and may be appropriately set in consideration of the physical properties of the raw material resin containing 90% by mass of 4-methyl-1-pentene (co)polymer, but stretching is performed at 50 ° C. or higher. It is particularly preferable to stretch at 80° C. or higher. By stretching at a temperature equal to or higher than the above temperature, it is possible to efficiently produce a stretched film with little distortion after stretching and small thermal dimensional change.
Further, it is preferable to draw at a temperature lower than the melting point of the 4-methyl-1-pentene (co)polymer used as the raw material resin, and it is particularly preferred to draw at a temperature lower than the melting point by 20°C or more. As described above, the preferred drawing temperature may vary depending on the melting point of the 4-methyl-1-pentene (co)polymer, so it is difficult to specify a value. ) When a polymer is used, it is preferably drawn at a temperature of less than about 230°C, and particularly preferably at a temperature of less than about 210°C. By stretching at a temperature lower than the above temperature, it is possible to efficiently produce a stretched film while sufficiently suppressing breakage and the like.

After the stretching step, preferably after the biaxial stretching step, heat setting treatment (heat setting treatment) is performed to hold the stretched film at a predetermined temperature for a certain period of time, thereby appropriately adjusting the thermal dimensional change rate of the film. can do.
The temperature of the heat setting treatment is not particularly limited, but from the viewpoint of effectively removing strain, it is preferably the temperature of the biaxial stretching process or higher, and the 4-methyl-1-pentene (common ) preferably at a temperature below the melting point of the polymer. For example, heat setting treatment is preferably performed at a temperature of 50° C. or higher and 230° C. or lower, and preferably at a temperature of 80° C. or higher and 210° C. or lower.
The heat setting time is not particularly limited, but is usually 5 to 300 seconds, particularly preferably 10 to 120 seconds.
The original film before stretching may or may not have a tensile yield point, but within the range of the stretch ratio described above in the present embodiment, even a film having a yield point is preferably used. can be done.
In addition, when the film before stretching has a yield point, it is preferable to set the stretching ratio so as not to reach the yield point from the viewpoint of preventing cracks. The presence or absence of a yield point can be confirmed by measuring the tensile stress/strain characteristics of the original film. More specifically, the presence or absence of the tensile yield point of the original film is determined by measuring the tensile stress/strain characteristics according to JIS K7161, and confirming the presence or absence of the point where the strain increases even though the stress does not increase as the yield point. can do.
The presence or absence of the tensile yield point in the original film can also be estimated by performing the same measurement on the stretched film. In this case, if the existence of the yield point is observed in the stretched film by the same measurement, it is presumed that the original film also has the yield point.

Manufacturing process The film of the present invention can be preferably used as a release film for processing. It can be used by placing it between By using the film of the present invention as a mold release film for processes, it is possible to effectively prevent mold release failure, burr generation, and the like.
The resin used in the above manufacturing process may be either a thermoplastic resin or a thermosetting resin, but thermosetting resins are widely used in the technical field, and epoxy-based thermosetting resins are particularly used. It is preferable to use
The most representative manufacturing process is sealing of semiconductor chips, but it is not limited to this, and the film of the present invention can also be applied to fiber-reinforced plastic molding processes, plastic lens molding processes, and the like. can be done.

FIG. 2 is a schematic diagram showing an example of a method for manufacturing a resin-encapsulated semiconductor using the film of the present invention.
As shown in FIG. 2(a), the film 15 of the present invention is fed into the upper die 13 from a roll-shaped roll by rolls 16-1 and 16-2. Next, the film 15 is arranged on the inner surface of the upper mold 13 . If necessary, the inner surface of the upper mold 13 may be evacuated from the suction port 12a to bring the film 15 into close contact with the inner surface of the upper mold 13 . A semiconductor chip 17 arranged on a substrate is arranged in a lower mold 14 of a molding apparatus. By injecting the sealing resin 18, the sealing resin 18 is housed between the upper mold 13 and the lower mold 14 on which the film 15 which has been exhausted and sucked and adhered is arranged. Next, as shown in FIG. 2B, the upper mold 13 and the lower mold 14 are closed via the film 15 of the present invention, and the sealing resin 18 is cured.

As shown in FIG. 2(c), the sealing resin 18 is fluidized into the mold due to the mold closing and hardening, and the sealing resin 18 flows into the space and fills the semiconductor chip 17 so as to surround the side surface of the semiconductor chip 17 for sealing. The semiconductor chip 17 (semiconductor package 17-2) thus formed is opened by the upper mold 13 and the lower mold 14 and taken out. After the mold is opened and the molded article is taken out, the film 15 can be reused multiple times or a new film can be supplied and subjected to the next resin molding.

The film of the present invention is brought into close contact with the upper mold, interposed between the mold and the sealing resin, and resin-molded to prevent the resin from adhering to the mold. Moreover, the molded article can be easily released from the mold.
Incidentally, the (mold release) film can be newly supplied for each resin molding operation and resin-molded, or can be newly supplied for each resin-molding operation and resin-molded.

The encapsulating resin may be a liquid resin or a resin that is solid at room temperature, but a sealing material that becomes liquid when resin-encapsulated can be used as appropriate. Specifically, epoxy resins (biphenyl type epoxy resins, bisphenol epoxy resins, o-cresol novolac type epoxy resins, etc.) are mainly used as sealing resin materials, and polyimide resins ( Bismaleimide-based resins), silicone-based resins (thermosetting addition type), and the like, which are commonly used as encapsulating resins, can be used. The resin sealing conditions may vary depending on the sealing resin used, but may be appropriately set, for example, within the range of curing temperature of 120° C. to 180° C., molding pressure of 10 to 50 kg/cm ² , and curing time of 1 to 60 minutes. can.

The process of arranging the film 15 on the inner surface of the upper mold 13 and the process of arranging the semiconductor chip 17 are not particularly limited, and may be performed at the same time, or the film 15 may be arranged after the semiconductor chip 17 is arranged. Alternatively, the semiconductor chip 17 may be placed after the film 15 is placed.

In this way, the film 15 uses 4-methyl-1-pentene (co)polymer with high releasability, so that the semiconductor package 17-2 can be easily released from the mold. Moreover, since the film 15 has appropriate flexibility, it is difficult to wrinkle due to the heat of the molding dies 13 and 14 while being excellent in followability to the mold shape. Therefore, the sealed semiconductor package 17-2 with a good appearance is prevented from being transferred wrinkles to the resin-sealed surface of the sealed semiconductor package 17-2 and without having a portion not filled with resin (resin chipping). 17-2 can be obtained.

Further, the transfer molding method of injecting a fluid sealing resin material may be employed instead of the compression molding method of pressurizing and heating the solid sealing resin material 18 as shown in FIG.

The film of the present invention is not limited to the process of resin-sealing a semiconductor element, but the process of molding and releasing various molded products using a molding die, press, etc., for example, the process of resin-sealing an LED element, the FPC (flexible It can be preferably used as a release film or the like in the pressing process of printed circuit boards, the manufacturing process of coating substrates, the molding and releasing processes of fiber-reinforced plastics such as CFRP, and the molding and releasing processes of plastic lenses.

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

In the following examples/comparative examples, physical properties/characteristics were evaluated by the following methods.
(Thermal dimensional change rate)
A film sample was cut into a length of 20 mm and a width of 4 mm in the longitudinal direction and width direction of the film, respectively, using a TMA (thermo-mechanical analyzer, product name: Q400) manufactured by TA Instruments Co., Ltd., at a distance between chucks of 8 mm. After being held at 23°C for 5 minutes with a load applied, the temperature was raised from 23°C to 150°C at a temperature increase rate of 10°C/min, and the dimensional change in each direction was measured. rate was calculated.

Thermal dimensional change rate (%) (23→150° C.) = {[(L ₂ −L ₁ )/L ₁ ]×100}
... (1)
L ₁ : Sample length (mm) at 23°C
_L2 : Sample length (mm) at 150°C

(Evaluation of wrinkles)
As shown in FIG. 1, a film 5 was sandwiched between a film holding frame 1 and a mold 4 including a vacuum suction area 2, and the whole was heated with a planar heater (not shown). The surface temperature of the film 5 was measured, and vacuum adsorption was performed when it reached 150°C. After that, the presence or absence of wrinkles in the film 5 on the vacuum adsorption area 2 was evaluated according to the following criteria.
◯: The film has no wrinkles at all.
x: The film has wrinkles.

(Presence or absence of yield point (tensile yield point))
A tensile test was performed using a tensile tester with a constant temperature chamber "RTC-1225" manufactured by A&D Co., Ltd. under the conditions of a sample width of 15 mm, a distance between chucks of 50 mm, and a speed of 300 mm/min.
The measurement temperatures were 160°C and 200°C.
According to JIS K7161, the presence or absence of a yield point was determined as the point at which the strain increased even though the stress did not increase.

[Example 1]
Opulent (registered trademark) X44B (thickness 50 μm, manufactured by Mitsui Chemicals Tohcello Co., Ltd.: 4-methyl-1-pentene (co)polymer film (unstretched film) as a 4-methyl-1-pentene (co)polymer film Coalescence: 99% by mass or more), and sequential biaxial stretching was performed with a batch biaxial stretching machine (KARO IV manufactured by Bruckner). More specifically, the film was first stretched in the MD direction during film formation of the original film, and then stretched in the TD direction.
Detailed stretching conditions are as follows.
Distance between chucks: 180 mm in both MD and TD directions
Preheating temperature: 160°C
Preheating time: 60 seconds Stretching temperature: 160°C
Stretching ratio MD direction: 1.05 times TD direction: 1.02 times Stretching speed: 1%/sec The obtained biaxially stretched film was subjected to measurement of thermal dimensional change rate and evaluation of wrinkles by the above methods. Table 1 shows the results.
Using the same biaxially stretched film, the presence or absence of a tensile yield point was confirmed by the above method. A tensile yield point was observed at 160° C. and 200° C., confirming that the original film had a tensile yield point.

(Examples 2 and 4 to 6)
Using the original 4-methyl-1-pentene (co)polymer film having the tensile yield point used in Example 1, except that the stretching temperature and/or stretching ratio were changed as shown in Table 1. In addition, a biaxially stretched film was produced and evaluated in the same manner as in Example 1. Table 1 shows the results.

(Example 3)
Using the original 4-methyl-1-pentene (co)polymer film having the tensile yield point used in Example 1, simultaneous biaxial stretching was performed instead of sequential biaxial stretching (raw film formation A biaxially stretched film was prepared in the same manner as in Example 2 (the device, the distance between chucks, the preheating temperature, the preheating time, and the stretching speed were not changed) except that the MD direction and the TD direction were stretched at the same time). was manufactured and evaluated. Table 1 shows the results.

(Example 7)
Using the original 4-methyl-1-pentene (co)polymer film having the tensile yield point used in Example 1, it was stretched in the same manner as in Example 6, and then at a temperature of 200° C. while being chucked. Heat setting was performed by holding for 60 seconds.
For the biaxially stretched film after heat setting, the thermal dimensional change rate was measured and wrinkles were evaluated by the methods described above. The results are shown in Table 1.

(Comparative example 1)
The 4-methyl-1-pentene (co)polymer film raw material (unstretched film) having a tensile yield point used in Example 1 was not subjected to biaxial stretching or the like, and the thermal dimensional change rate was measured as it was, and Wrinkles were evaluated. Table 1 shows the results.

(Comparative example 2)
The original 4-methyl-1-pentene (co)polymer film (unstretched film) having the tensile yield point used in Example 1 was uniaxially stretched in the MD direction at 160° C. at a stretch ratio of 1.10 times. .
The obtained uniaxially stretched film was measured for thermal dimensional change and evaluated for wrinkles by the methods described above. Table 1 shows the results.

(Comparative Example 3)
Using the original 4-methyl-1-pentene (co)polymer film having the tensile yield point used in Example 1, except that the stretching temperature and stretching ratio were changed as shown in Table 1, A biaxially stretched film was produced in the same manner as in Example 3. Table 1 shows the results.
Cracks were generated during stretching, and a stretched film that could be used for evaluation of wrinkles and thermal dimensional change was not obtained.

The film of the present invention has releasability, recyclability, and wrinkle-suppressing performance at a high level that could not be achieved by conventional techniques. Molded products obtained by encapsulating chips with resin can be easily released from the mold, and molded products without appearance defects such as wrinkles can be manufactured with high productivity. Since technical effects having high practical value such as being recyclable can be realized, it has high applicability in various industrial fields including the semiconductor process industry.
In addition, the film of the present invention can be used not only for semiconductor encapsulation, but also for LED resin encapsulation, FPC press, coating substrate, fiber reinforced plastic molding process, etc. It has high applicability in each field of industry other than the above.

1: Film holding frame 2: Vacuum adsorption area 4: Mold
5: Film 12a: Suction port 13: Upper mold 14: Lower mold 15: Films 16-1, 16-2: Roll 17: Semiconductor chip 17-2: Semiconductor package 18: Sealing resin

Claims (8)

The thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C is 3% or less, and the thermal dimensional change rate in the transverse (TD) direction from 23°C to 150°C and the longitudinal (MD) direction at 23°C A film containing 90% by mass or more of a 4-methyl-1-pentene (co)polymer having a sum of 6% or less of thermal dimensional change from temperature to 150°C. 2. The film of claim 1, wherein said film is a monolayer film. Both the longitudinal (MD) direction and transverse (TD) direction draw ratios are 1.01 times or more, and the area ratio represented by the longitudinal (MD) direction draw ratio × transverse (TD) direction draw ratio is The film according to claim 1 or 2, which is a biaxially stretched film of 1.02 to 2.00 times. 4. The film according to any one of claims 1 to 3, wherein the thermal dimensional change from 23[deg.]C to 150[deg.]C in the transverse (TD) direction is 0% or more. The method for producing the film according to any one of claims 1 to 4, comprising a step of biaxially stretching a raw film containing 90% by mass or more of 4-methyl-1-pentene (co)polymer, , The above production method, wherein the biaxial stretching is carried out at a temperature of 50°C or higher and lower than the melting point of the 4-methyl-1-pentene (co)polymer. 5. After the step of biaxially stretching, further comprising a step of performing a heat setting treatment at a temperature equal to or higher than the temperature of the biaxial stretching and lower than the melting point of the 4-methyl-1-pentene (co)polymer. The manufacturing method described in . 5. The film according to any one of claims 1 to 4, which is a release film. The film according to any one of claims 1 to 4, which is a release film for a semiconductor encapsulation process.

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