JP2021106187A - Polyolefin-based resin film and adhesive sheet using the same - Google Patents

Abstract

To provide a polyolefin-based resin film that is applicable to heating treatment in a process of coating an adhesive layer or the like, generates little foreign material or the like, and has excellent expandability.SOLUTION: A polyolefin-based resin film takes, as at least one surface layer, a layer that contains polyethylene-based resin particles and polyolefin-based resin other than the polyethylene-based resin particles and substantially does not contain an organic slipping agent other than the polyethylene-based resin particles. The maximum projection height of the at least one surface layer is equal to or larger than 2 μm and equal to or smaller than 15 μm.SELECTED DRAWING: None

Description

INDUSTRIAL APPLICABILITY The present invention is mainly suitable for being used as a base film of an pressure-sensitive adhesive sheet for fixing semiconductors and the like when cutting and separating them to obtain chips, and also for plastic products, glass products, ceramic products and the like. The present invention relates to a polyolefin-based resin film that can also be applied to a base film of a surface protective film that protects the surface condition that has been subjected to conductivity, decoration, etc.

The semiconductor manufacturing process includes a dicing process for cutting and separating a substrate obtained by a die bonding process for laminating a semiconductor wafer such as silicon or gallium arsenic or a chip of the semiconductor wafer on a plastic product, a glass product, a ceramic product, or the like. An adhesive sheet in which a semiconductor wafer or substrate is fixed in the dicing process, and an adhesive layer is provided on at least one side of a resin film as a base material in order to prevent misalignment due to dicing by blades and scattering of chips and the like. Is used as a dicing tape.

The dicing tape also undergoes an expandable property for an expanding process in which the intervals between the dicing tapes are widened so that the chips separated by a suction jig or the like can be easily picked up, and a pick-up process for collecting the chips. Flexibility is required to reduce the load.

For example, a multilayer film in which a resin composition composed of a vinyl aromatic hydrocarbon or a conjugated diene hydrocarbon copolymer hydrogen additive and a polypropylene-based resin is laminated is known (for example, Patent Document 1). However, although the multilayer film as described above is generally satisfactory in expandability, it is not always satisfactory in terms of deflection due to the weight of the wafer and the like.

Further, a resin layer containing a friction reducing agent such as silicon oil, silicon resin powder or tetrafluoroethylene resin powder is provided on a base material of an ethylene resin such as ethylene-ethyl acrylate (EEA) and ethylene vinyl alcohol (EVA). Films for base materials are known (for example, Patent Document 2). Generally, the above-mentioned film for a base material is satisfactory in expandability and flexibility, but it has an influence on the environment due to contamination of chips by silicone oil and generation of hydrogen fluoride gas during incineration by ethylene tetrafluoride resin powder. I am concerned.

Further, in an ethylene-based resin film, a film for a base material that reduces friction and secures expandability by providing a layer to which silica particles are added on the opposite surface to which an adhesive layer or the like is applied is disclosed ( For example, Patent Document 3). However, in general, silica particles have a heavy specific gravity and tend to aggregate, and there is a concern that it may be difficult to control foreign substances such as fish eyes.

JP-A-2009-94418 JP-A-7-221052 Japanese Unexamined Patent Publication No. 11-189755

The present invention is mainly suitable as a base film for an adhesive sheet for fixing semiconductors and the like when cutting and separating them to obtain chips, and is also conductive in plastic products, glass products, ceramic products and the like. , A polyolefin-based resin film that can also be applied to the base film of a surface protection film that protects the surface condition with decoration, etc., and can be used for heat treatment in the coating process of the pressure-sensitive adhesive layer, etc. It is an object of the present invention to provide a polyolefin-based resin film which is less likely to occur and has excellent expandability.

As a result of diligent studies to solve the above problems, the present inventors have expanded property by arranging polyethylene-based resin particles on the surface layer on at least one side to form specific surface irregularities. We have found that the weight of a wafer or the like reduces deflection, and that a polyolefin-based resin film that does not cause defects in the base film during heat treatment in a coating process such as an adhesive layer can be obtained, and the present invention has been completed. ..

That is, the present invention has the following configuration.
1. 1. A polyolefin-based resin film containing at least one surface layer containing polyethylene-based resin particles and a polyolefin-based resin other than the polyethylene-based resin particles and substantially free of an organic slip agent other than the polyethylene-based resin particles. A polyolefin resin film having a maximum protrusion height of 2 μm or more and 15 μm or less on at least one of the surface layers.
2. The first item described above, wherein the polyethylene-based resin forming the polyethylene-based resin particles has a viscosity average molecular weight of 1.5 million or more, and a melting point of 150 ° C. or less according to JIS K 7121: 2012 “Method for measuring transition temperature of plastic”. Polyolefin resin film.
3. 3. The polyolefin-based resin film according to the first or second method, wherein the surface layers having a maximum protrusion height of 2 μm or more and 15 μm or less have a coefficient of static friction of 0.9 or less.
4. Polyolefin-based resins other than the polyethylene-based resin particles include homopolymers of ethylene monomers, copolymers containing 80% by mass or more of linear low-density polyethylene and one or more α-olefins as comonomer, and The polyolefin-based resin film according to any one of the above 1 to 3, which is a mixture containing these.
5. The first-to-first polyolefin resin other than the polyethylene-based resin particles is a polypropylene homopolymer, a copolymer containing 70% by mass or more of propylene and one or more α-olefins as comonomers, and a mixture containing these. The polyolefin-based resin film according to any one of the third.
6. The polyolefin-based resin film according to the fourth or fifth above, wherein the polyolefin-based resin other than the polyethylene-based resin particles further contains at least 5% by mass or more of an ethylene-acrylic acid ester copolymer.
7. A pressure-sensitive adhesive sheet having an pressure-sensitive adhesive layer on at least one side of the polyolefin-based resin film according to any one of the first to sixth aspects.

Since the polyolefin-based resin film of the present invention uses a polyolefin-based resin, it has flexibility to exhibit appropriate expandability, and polyethylene-based resin particles are arranged on at least one surface layer. , Friction is reduced, and more uniform expandability can be obtained. In addition, since it does not substantially contain an organic slip agent other than the polyethylene-based resin particles, it is easy to control the influence on the environment and foreign substances. Therefore, the polyolefin-based resin film of the present invention is mainly suitable as a base film for an pressure-sensitive adhesive sheet for fixing semiconductors and the like when cutting and separating them to obtain chips, and also for a pressure-sensitive adhesive layer and the like. A surface that protects the surface condition of plastic products, glass products, ceramic products, etc. that has been subjected to conductivity, decoration, etc. because it can be used for heat treatment in the coating process, generates less foreign matter, and has excellent expandability. It is possible to provide a polyolefin-based resin film that can also be applied to a base film of a protective film.

The polyolefin-based tree film of the present invention has, for example, a compound described below, a structure, and the like.

<Surface texture>
At least one surface layer of the polyolefin-based resin film of the present invention contains polyethylene-based resin particles, and the surface of the surface layer preferably has a maximum protrusion height of 2 μm or more, and preferably 15 μm or less. preferable. When the maximum protrusion height is 2 μm or more, the friction on the surface can be reduced, which is preferable. More preferably, the maximum protrusion height of the surface is 3 μm or more. On the other hand, when the maximum protrusion height is 15 μm or less, it is preferable that the appearance quality without flicker can be obtained. More preferably, the maximum protrusion height of the surface is 10 μm or less. Then, 15 [mu] m or more number of projections is preferably be one /0.2Mm ² or less, more preferably 0.5 pieces / mm ² or less.

In the polyolefin-based resin film of the present invention, the coefficient of static friction on the surface of at least one surface layer containing polyethylene-based resin particles is preferably 0.10 or more, more preferably 0.15 or more. Further, 0.7 or less is preferable, and 0.5 or less is more preferable. The coefficient of static friction is the coefficient of static friction between at least one surface layer containing polyethylene-based resin particles.

When the coefficient of static friction is 0.10 or more, it is preferable because there is no possibility that the roll may be rolled or the winding may be misaligned in the film forming process or the processing process. If the coefficient of static friction is 0.7 or less, there is no risk of problems such as wrinkles, and when a semiconductor or the like is cut and separated to obtain chips, when a base film of an adhesive sheet for fixing these is used as a base film. It is preferable that uniform expandability can be obtained in the expanding step.

<Polyethylene resin particles>
In the present invention, it is preferable that the polyethylene-based resin particles contained in at least one surface layer have a viscosity average molecular weight of 1.5 million or more, and the melting point according to JIS K 7121: 2012 “Method for measuring transition temperature of plastic” is high. It may cause filter clogging during melt extrusion, and if it is low, it may flatten and do not function as protrusions during melt extrusion. Therefore, the peak temperature is preferably 130 ° C. or higher and 150 ° C. or lower.

In the present invention, if the average particle size of the polyethylene-based resin particles contained in the surface layer is small, it may not function as a protrusion, and if it is large, it may cause foreign matter or filter clogging during melt extrusion. 2 μm or more is preferable, 3 μm or more is more preferable, and 5 μm or more is further preferable. Further, 15 μm or less is more preferable, and 10 μm or less is further preferable.

In addition, it is preferable that 1% by mass or more of coarse particles having a size of 25 μm or more are not contained. More preferably, it is not contained at all. Even if the average particle size is 15 μm or less, if the content of particles of 25 μm or more (hereinafter, coarse particles) is less than 1% by mass, there are no large protrusions derived from these coarse particles on the film surface, and the film surface has no large protrusions. So-called flicker does not occur, which is preferable.

Regarding the particle size, the particle size distribution was obtained in accordance with JIS Z 8832: 2010 "Particle size distribution measurement method Electrical detection band method", and the median size at which the frequency of occurrence was 50% was taken as the average particle size. .. In addition, the amount of coarse particles was determined from the distribution of the particle size.

Further, the average particle size of the particles in the film can be measured as follows, and the data of the method based on JIS Z 8832: 2010 can be estimated. For example, the particles in the cross section of the film are observed with a scanning electron microscope, 50 particles are observed, and the average value thereof is used as the average particle diameter. The shape of the particles is not particularly limited, and spherical particles and amorphous non-spherical particles can be used. In the measurement method by microscopic observation, the particle size of the amorphous particles can be calculated as a circle-equivalent diameter. The equivalent circle diameter is a value obtained by dividing the observed particle area by π, calculating the square root, and doubling it.

The polyethylene-based material constituting the polyethylene-based resin particles in the present invention preferably has a viscosity average molecular weight of 1.5 million or more, more preferably 1.6 million or more, and further preferably 1.7 million or more. Further, it is preferably 2.5 million or less, more preferably 2.2 million or less, and further preferably 2 million or less.

Although the reason is not clear, if the viscosity average molecular weight is in this range, the difference in molecular weight between the polyethylene-based resin particles and the other polyolefin-based resins constituting the base film is very large, so that the molecules do not mix. After melting and mixing, the shape of the polyethylene-based resin particles can be maintained even in the film obtained by extrusion, and since aggregation due to fusion and adhesion of the particles is unlikely to occur, the surface of the film is inorganic. It is presumed that protrusions matching the particle size can be formed in the same way as particles.

Further, when the viscosity average molecular weight of the polyethylene-based resin particles is 1.5 million or more, it is difficult to decompose due to heat or shearing during melting and mixing, and the particle shape changes due to fusion aggregation and partial compatibility with the base resin. Since it is unlikely to occur, it is preferable that appropriate protrusions are easily formed, the function as an anti-blocking agent is maintained, the appearance such as transparency, and the mechanical strength of the film are maintained.

On the other hand, even if the viscosity average molecular weight is 2.5 million or less, the shape of the particles can be easily maintained when the film obtained by extrusion after melting and mixing is formed, and the protrusions on the film surface can be effectively formed. ..
The viscosity average molecular weight is based on JIS K7252: 2016 "Plastic-How to obtain the average molecular weight and molecular weight distribution of a polymer by size exclusion chromatography-", and the intrinsic viscosity and the value obtained from the Mark Howink Sakurada formula. Can be applied.

In the present invention, the content of the polyethylene-based resin particles in the surface layer depends on the average particle size and the thickness of the surface layer, but is generally preferably 0.5% by mass or more, preferably 1.0% by mass or more. More preferred. Further, it is preferably 3.0% by mass or less. When the amount of the polyethylene-based resin particles added is 0.5% by mass or more, it is easy to set the maximum protrusion height of at least one surface layer to 2 μm or more, which is preferable. On the other hand, when it is 3.0% by mass or less, there is no risk of lip stains during extrusion, and there is no risk of poor appearance, which is preferable.

<Structure>
The polyolefin-based resin film of the present invention can have a layer structure of A: single layer, A / B, A / C, A / B / A, A / B / C, etc. by the following resin, and further, between layers. , It is also possible to provide another layer such as a polyolefin resin.

Layers A and C: Layers containing polyethylene-based resin particles Layer B: Layers not containing polyethylene-based resin particles

<Thickness>
The overall thickness of the polyolefin-based resin film of the present invention is preferably 60 μm or more, more preferably 80 μm or more. Further, it is preferably 180 μm or less from the viewpoint of handleability.

When the total thickness of the polyolefin-based resin film of the present invention is 60 μm or more, there is a feeling of waist, and further, when cutting and separating semiconductors and the like to obtain chips, the base film of the pressure-sensitive adhesive sheet that fixes them. In the above case, uniform expandability can be obtained, which is preferable.

When a layer containing polyethylene-based resin particles is arranged as at least one surface layer of the polyolefin-based resin film of the present invention, the thickness of the surface layer is preferably half or more of the average particle size of the polyethylene-based resin particles. .. On the other hand, the thickness of the surface layer is preferably the same as or less than the average particle size of the polyethylene-based resin particles, and more preferably 1 μm or more smaller than the average particle size of the polyethylene-based resin particles.

When the thickness of the surface layer containing the polyethylene-based resin particles is at least half the average particle size of the polyethylene-based resin particles, lip stains do not occur during extrusion and there is no risk of poor appearance, which is preferable. On the other hand, when the thickness of the surface layer containing the polyethylene-based resin particles is equal to or less than the average particle size of the polyethylene-based resin particles, it is preferable that the maximum protrusion height of the surface layer can be obtained.

<Polyolefin resin>
The surface layer located on at least one side of the polyolefin resin film of the present invention contains polyethylene-based resin particles as described above, and as the polyolefin-based resin forming the surface layer, a homopolymer of ethylene monomer, A copolymer containing 80% by mass or more of linear low-density polyethylene and one or more α-olefins as a comonomer, an olefin resin having improved compatibility with polar rubber, and a mixture containing at least two of these. Is preferably contained. Since polyethylene has little bleed-out of low molecular weight substances, low-density polyethylene produced with a metallocene catalyst is desired, and in the case of copolymers, linear low-density polyethylene is 80% by mass or more. In the coating process of an adhesive or the like, it is preferable because it is difficult to adhere to the process roll even if it is heated for drying, and it is difficult for wrinkles to occur.

Further, the surface layer located on at least one side of the polyolefin-based resin film contains polyethylene-based resin particles as described above, and is a polypropylene homopolymer, in which propylene is 70% by mass or more and one or more α-olefins are comonomer. It is also preferable to contain the above-mentioned copolymer and a mixture containing these. It is used as a polyolefin resin applied to the polyolefin resin film of the present invention, and when propylene is 70% by mass or more, it is difficult to adhere to the process roll even if it is heated for drying in the coating process of an adhesive or the like. It is preferable because wrinkles are unlikely to occur.

The α-olefin in the polyolefin resin mainly applied to the surface layer of the polyolefin resin film of the present invention is propylene, 1-butene, 1-hexene, 1-decene, 1-octene, 4-methyl-1-pentene. , 1-Nonen, 4-Methyl-1-hexene and the like are exemplified, and butene-1, pentene-1, hexene-1, 4-methyl-1-pentene and the like are used from the viewpoint of improving break resistance and expandability. preferable.

Further, in the surface layer located on at least one side of the polyolefin-based resin film, the contained polyolefin-based resin further forms a surface layer of an ethylene-acrylic acid ester copolymer in addition to the above-mentioned polyolefin resin. It is preferable that the amount of the polyolefin resin other than the polyethylene-based resin particles is at least 5% by mass or more from the viewpoint of improving expandability, and it is preferably 25% by mass or less from the viewpoint of precipitation of low molecular weight substances. Further, it is preferable to introduce an acrylic acid ester exemplified by methyl acrylate, ethyl acrylate, butyl acrylate and 2 ethyl hexyl acrylate in place of the alkyl group at the position where the alkyl group of α-olefin is bonded.

In addition, the polyolefin-based resin film of the present invention contains known inorganic compound particles such as silica, talc, zeolite and aluminum borate, polymethyl methacrylate, melamine formalin resin, melamine urea resin, and polyester, as long as the purpose is not impaired. It is possible to add organic compound particles such as resin. However, it is exemplified by hydrocarbons such as liquid paraffin, paraffin wax and synthetic polyethylene wax, aliphatic / higher alcohols such as stearic acid and stearyl alcohol, fatty acid amides such as stearic acid amide, oleic acid amide and erucic acid amide. Since there is a concern that the organic slip agent may be contaminated by bleeding, it is preferable that the organic slip agent is substantially not contained. In the present invention, it is said that the organic slip agent is not substantially contained, and the total amount of extraction by Soxhlet extraction with chloroform in accordance with JIS K6229: 2015 "Method for obtaining rubber-solvent extract (quantitative)" is 1. It means that it is not detected by mass% or less, and is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and not detected for each organic solvent.

Melt flow rate (MFR) based on JIS K6921: 2010 "Plastic-Polypropylene (PP) molding and extrusion materials-Part 2: Specimen preparation method and property determination method" for the polyolefin resin used in the present invention. Although it depends on the width and thickness of the target sheet, 1 to 20 g / 10 min is preferable, and 2 to 8 g / 10 min is more preferable. When the MFR is 1 g / 10 min or more, extrusion becomes easy, which is preferable. When the MFR is 20 g / 10 min or less, the thickness variation of the sheet can be reduced, which is preferable.

The polyolefin-based resin raw material used in the present invention is not particularly limited, such as petroleum-derived or plant-derived, but is preferably plant-derived from the viewpoint of the environment.

<Film formation of polyolefin resin>
The polyolefin-based resin film used in the present invention can be obtained by extrusion molding, calendar molding, or the like.

Extrusion molding involves extrusion from a T-die into a sheet through a single-screw or twin-screw screw extruder. The extruded sheet is cooled and solidified by pressing it against the surface of a metal roll in which cooling water or oil circulates with an air knife, an air chamber, a hard rubber roll, a steel belt, a metal roll, or the like. Further, both sides of the sheet can be sandwiched between steel belts to be cooled and solidified. In addition to the extruder used for forming the polyolefin resin sheet of the present invention into a sheet, it is also possible to obtain a heterogeneous multilayer sheet by using an extruder such as a recycled resin and a feed block or a multi-manifold.

The polyolefin-based resin film of the present invention can be stretched uniaxially or biaxially as needed, and if the total draw ratio is high, the expandability may be impaired, and if it is low, the thickness varies. Is likely to be large, so it is preferably 3 to 12 times each in both the vertical and horizontal directions.

<Adhesive>
For adhesive sheets that fix semiconductors when cutting and separating them to obtain chips, and surface protective films that protect the surface condition of plastic products, glass products, ceramic products, etc. that have been subjected to conductivity and decoration. When applied, it is preferable to provide an adhesive layer on the polyolefin-based resin film.

Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer include (meth) acrylic pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, olefin-based pressure-sensitive adhesive, and styrene-based pressure-sensitive adhesive. A (meth) acrylic pressure-sensitive adhesive that can be easily adjusted is preferable.

Examples of the (meth) acrylic polymer contained in the (meth) acrylic pressure-sensitive adhesive include a homopolymer of a (meth) acrylic acid ester compound, a copolymer of a (meth) acrylic acid ester compound and a comonomer, and the like. Can be mentioned. Examples of the (meth) acrylic acid ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxyethyl (meth) acrylate, and hydroxypropyl (meth). Examples thereof include acrylate, dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate. These (meth) acrylic acid ester compounds may be used alone or in combination of two or more. The comonomer constituting the (meth) acrylic copolymer includes vinyl acetate, (meth) acrylonitrile, (meth) acrylic amide, styrene, (meth) acrylic acid, itaconic acid, (meth) acrylic amide, and methylol. Examples thereof include (meth) acrylicamide and maleic anhydride, and these copolymers may be used alone or in combination of two or more.

As the above-mentioned pressure-sensitive adhesive, a radiation-crosslinked pressure-sensitive adhesive that reduces the adhesive strength by radiation can be used, and the pressure-sensitive adhesive layer formed by cross-linking by radiation irradiation significantly reduces the adhesive strength. It will be easier to pick up.

As such a radiation cross-linking type pressure-sensitive adhesive, a pressure-sensitive adhesive such as the above-mentioned (meth) acrylic pressure-sensitive adhesive and a resin containing a cross-linking compound and a photopolymerization initiator are used.
Examples of the crosslinkable compound include monomers, oligomers, and polymers that can be crosslinked by radical polymerization. Trimethylol propantri (meth) acrylate, pentaerythritol tri (meth) acrylate, and tetraethylene glycol di (meth) acrylate. , 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate and other (meth) acrylic acids and polyhydric alcohol esters; ester (meth) acrylate Oligomers; isocyanurates such as 2-propenyldi-3-butenyl cyanurate, 2-hydroxyethylbis (2- (meth) acryloxyethyl) isocyanurate, tris (2-methacryloxyethyl) isocyanurate, or isocyanurate compounds, etc. Can be exemplified. The content of these crosslinkable compounds depends on the compound to be selected, but from the viewpoint of adjusting the viscosity of the solution at the time of coating and adjusting the adhesive strength, 5 to 100 parts by mass of the adhesive is used. By mass is preferable, and 10 to 50 parts by mass is more preferable.

The photopolymerization initiator may be any compound that is cleaved by irradiation to generate a radical, and benzoin alkyl ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether, as well as benzyl, benzoin, and benzophenone. Examples thereof include aromatic ketones such as α-hydroxycyclohexylphenyl ketone, aromatic ketals such as benzyldimethyl ketal, and thioxanthones such as polyvinylbenzophenone; chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone.

The thickness of the pressure-sensitive adhesive layer by the above-mentioned pressure-sensitive adhesive is not particularly limited, but is preferably 1 to 50 μm, preferably 3 to 30 μm, from the viewpoint of adhesive strength, uniformity of the thickness of the pressure-sensitive adhesive layer, and the like. More preferred.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples, and can be modified and implemented within a range suitable for the gist of the present invention, all of which are included in the technical scope of the present invention.

The method for evaluating the physical properties in the examples is as follows.

(1) Membrane-forming property (lip stain)
When the film-forming time was 5 hours, the lip condition on the die and the film-forming surface were observed and evaluated according to the following criteria.
◎: No lip stains are found and there is no abnormality on the film-forming surface ○: There are signs of lip stains, but there are no abnormalities on the film-forming surface △: Lip stains can be confirmed, but there are no abnormalities on the film-forming surface ×: Lip stains are clear, and streaks are observed near the stains on the film-forming surface.

(2) Maximum protrusion height (Rz)
Using a contact-type surface roughness meter (manufactured by Kosaka Laboratory, model ET4000A), arbitrarily measure the surface roughness of the measurement surface 1 mm x 0.2 mm from a 3 cm x 3 cm square film, and perform this for 3 locations. , The average value was taken as the maximum protrusion height Rz.

(3) Number of protrusions of 15 μm or more (R15) (pieces / 0.2 mm ² )
For the number of protrusions of 15 μm or more, a contact type surface roughness (manufactured by Kosaka Laboratory, model ET4000A) is used, and the surface roughness of a measurement surface of 1 mm × 0.2 mm is arbitrarily measured from a 3 cm × 3 cm square film, and the protrusions are formed. The number of protrusions having a height of 15 μm or more was confirmed for three places, and the average value was taken as the number of protrusions R15 having a height of 15 μm or more.

(4) Static friction coefficient μs
In accordance with JIS P 8147: 2010 "Paper and Paperboard-Static and Dynamic Friction Coefficient Measurement Method (Inclination Method)", the tangent of the sliding angle between the surfaces containing polyethylene resin particles was defined as the static friction coefficient μs.

(5) Thickness The value obtained in accordance with JIS K 7130: 1999 "Method for measuring thickness of plastic film and sheet (method A)" was taken as the thickness.

(6) Expandability The olefin resin film of the sample is fixed to a 6-inch dicing frame with double-sided tape, and a concentric circle with a diameter of 50 mm and a diameter of 100 mm is drawn with respect to the center point, and then with respect to the inner diameter of the dicing frame. The film was expanded with an expander (stage: temperature 30 ° C., rising speed 50 mm / min, holding 60 sec) so as to have an elongation of 20%, and the following evaluation was performed from the elongation measured at a 45 deg pitch with respect to the concentric circles.

⊚: Elongation of 13% or more in all directions, maximum difference is less than 2% ○: Elongation of 13% or more in all directions, but maximum difference of 2 to 5% △: Some directions With elongation of 10 to 13%, there is a difference of up to 2-5% ×: There is an elongation of less than 10% in some directions, or there is a difference of up to 5% or more.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.

The following raw materials were used in Examples and Comparative Examples.
(Polyolefin resin)

<Resin 1>
Sumikasen E FV405 manufactured by Sumitomo Chemical Co., Ltd. (metallocene catalytic LLDPE, density: 924 kg / m ³ , MFR: 3.8 g / 10 min, melting point: 118 ° C., linear low density polyethylene: 90% by mass or more) was used as the resin 1. ..

<Resin 2>
Rexpearl EEA A4250 (ethylene-ethyl acrylate copolymer, ethyl acrylate content 25% by mass, MFR: 5 g / 10 min, melting point: 92 ° C.) manufactured by Japan Polyethylene Corporation was used as the resin 2.

<Resin 3>
Miperon (registered trademark) PM200 (ultra high molecular weight polyethylene particles, average particle diameter 10 μm, melting point 136 ° C., viscosity average molecular weight 1.8 million, particle size exceeding 25 μm) manufactured by Mitsui Chemicals Co., Ltd. is 0 in the above resin 1. %) Was contained in 15% by mass to prepare a pellet-shaped resin 3.

<Resin 4>
A pellet-shaped resin 4 containing 15% by mass of spherical silica (average particle size 12 μm, particle size exceeding 25 μm is 2%) in the above resin 1 was prepared.

<Examples 1 to 11 and Comparative Examples 1 to 3>
A mixture of pellets is kneaded in advance using two extruders so as to have a two-layer laminated structure, melt extrusion is performed from a T-die at a resin temperature of 240 ° C., and casting is performed on a cooling roll at a temperature of 40 ° C. , Examples 1 to 11 and Comparative Examples 1 to 3 were obtained. Table 1 shows the thickness, layer composition, resin compounding ratio, and evaluation results of Examples 1 to 11 and Comparative Examples 1 to 3.

From Examples 1 to 11, the polyolefin-based resin film containing the polyethylene-based resin particles of the present invention has no abnormality in film-forming property in terms of material composition and compounding ratio, and surface irregularities are also in a predetermined category. Since there is no foreign body sensation and good slipperiness, expandability can be obtained, and it is particularly suitable for use as a base material of an adhesive sheet for fixing these when cutting and separating semiconductors and the like to obtain chips. ..

By comparing Examples 1 and 2 with Comparative Examples 1 and 2, the polyolefin-based resin film has a problem that an appropriate protrusion height cannot be obtained unless particles made of polyethylene-based resin are used, and the expandability is improved. It turns out that it cannot be obtained.

When the maximum protrusion height of the surface of the layer containing the polyethylene-based resin particles in the polyolefin-based resin film of the present invention is increased according to Examples 1, 4, 8, 10 and Examples 2, 7, 9, and 11. There are signs that the film property is likely to deteriorate, and it can be seen that the problem becomes apparent unless the particles made of polyethylene resin are applied as in Comparative Example 3.

<Resin 5>
Evolu SP1071C manufactured by Prime Polymer Co., Ltd. (metallocene catalytic LLDPE, density: 911 kg / m ³ , MFR: 10 g / 10 min, melting point: 101 ° C., linear low density polyethylene: 90% by mass or more) was used as the resin 5.

<Resin 6>
Miperon (registered trademark) PM200 (ultra high molecular weight polyethylene particles, average particle diameter 10 μm, melting point 136 ° C., viscosity average molecular weight 1.8 million, particle size exceeding 25 μm) manufactured by Mitsui Chemicals Co., Ltd. is 0 in the above resin 5. %) Was contained in a pellet-shaped resin 6 in an amount of 15% by mass.

<Resin 7>
Noblen FW836DG3 (homo-polypropylene, density: 900 kg / m ³ , MFR: 7 g / 10 min, melting point: 158 ° C.) manufactured by Sumitomo Chemical Co., Ltd. was used as the resin 5.

<Resin 8>
Miperon (registered trademark) PM200 (ultra high molecular weight polyethylene particles, average particle diameter 10 μm, melting point 136 ° C., viscosity average molecular weight 1.8 million, particle size exceeding 25 μm) manufactured by Mitsui Chemicals Co., Ltd. is 0 in the above resin 7. %) Was contained in a pellet-shaped resin 6 in an amount of 15% by mass.

<Examples 12 to 15>
A mixture of pellets is kneaded in advance using two extruders so as to have a two-layer laminated structure, melt extrusion is performed from a T-die at a resin temperature of 240 ° C., and casting is performed on a cooling roll at a temperature of 40 ° C. , Examples 1 to 11 and Comparative Examples 1 to 3 were obtained in the same manner. Table 2 shows the thickness, layer structure, resin compounding ratio, and evaluation results in Examples 12 to 15.

Similar to the films of Examples 1 and 2, the films of Examples 12 to 15 have a surface layer containing polyolefin-based resin and polyethylene-based resin particles, so that the film-forming property is good and the surface irregularities are appropriately adjusted. Since it is made of polyethylene and has good slipperiness, expandability can be obtained, and it is particularly suitable as a base film for an adhesive sheet for fixing semiconductors and the like when cutting and separating them to obtain chips.

About 2 g of a sample was collected from Examples 1 to 15 and Comparative Examples 1 to 3, and after cutting, Soxhlet extraction with chloroform (extraction 4 hours) was performed, and the extract was 0.6% by mass or less. It was confirmed that no organic slip agent was detected by solid-state-NMR spectrum analysis.

Since the polyolefin-based resin film of the present invention uses a polyolefin-based resin for at least one side surface layer, it has flexibility to obtain appropriate expandability. Further, since polyethylene-based resin particles are contained in the surface layer on at least one side, friction is reduced and more uniform expandability can be obtained. Therefore, when cutting and separating a semiconductor or the like to obtain a chip. In addition, it is suitable for use as a base film for an adhesive sheet for fixing these, and also as a base material for a surface protective film that protects the surface condition of plastic products, glass products, ceramic products, etc. that has been subjected to conductivity, decoration, etc. It can also be applied to films. The industrial applicability of the present invention is extremely high.

Claims (7)

A polyolefin-based resin film containing at least one surface layer containing polyethylene-based resin particles and a polyolefin-based resin other than the polyethylene-based resin particles and substantially free of an organic slip agent other than the polyethylene-based resin particles. A polyolefin resin film having a maximum protrusion height of 2 μm or more and 15 μm or less on at least one of the surface layers. The first aspect of claim 1, wherein the polyethylene-based resin forming the polyethylene-based resin particles has a viscosity average molecular weight of 1.5 million or more and a melting point of 150 ° C. or less according to JIS K 7121: 2012 "Method for measuring transition temperature of plastic". Polyolefin resin film. The polyolefin-based resin film according to claim 1 or 2, wherein the static friction coefficient between the surface layers having a maximum protrusion height of 2 μm or more and 15 μm or less is 0.9 or less. Polyolefin-based resins other than the polyethylene-based resin particles include homopolymers of ethylene monomers, copolymers containing 80% by mass or more of linear low-density polyethylene and one or more α-olefins as comonomer, and The polyolefin-based resin film according to any one of claims 1 to 3, which is a mixture containing these. Claims 1 to claim that the polyolefin-based resin other than the polyethylene-based resin particles is a polypropylene homopolymer, a copolymer containing 70% by mass or more of propylene and one or more α-olefins as comonomers, and a mixture containing these. 3. The polyolefin-based resin film according to any one of 3. The polyolefin-based resin film according to claim 4 or 5, wherein the polyolefin-based resin other than the polyethylene-based resin particles further contains at least 5% by mass or more of an ethylene-acrylic acid ester copolymer. A pressure-sensitive adhesive sheet having an pressure-sensitive adhesive layer on at least one side of the polyolefin-based resin film according to any one of claims 1 to 6.