CN-122029026-A - Stretched polyolefin film, process for producing the same, and protective film for laminated film

Abstract

The invention provides a stretched polyolefin film capable of preventing blocking even if an anti-blocking agent is not contained. The present invention is a stretched polyolefin film comprising a polyolefin resin, wherein the stretched polyolefin film is stretched in at least one axial direction of an MD direction and a TD direction, and wherein at least one surface of the stretched polyolefin film has a deviation (Ssk) of 1.0 or less and a core height (Sk) of 0.04 [ mu ] m or more, as measured in a surface roughness measurement.

Inventors

• UEDA HIROAKI
• NAKAO AKIHIRO

Assignees

• 王子控股株式会社

Dates

Publication Date

20260512

Application Date

20241017

Priority Date

20231020

Claims (7)

1. 1. A stretched polyolefin film comprising a polyolefin resin, wherein, The stretched polyolefin film is stretched in at least one axial direction of the MD direction and the TD direction, The stretched polyolefin film has a degree of deviation (Ssk) of 1.0 or less and a core height (Sk) of 0.04 [ mu ] m or more, as measured in surface roughness measurement.
2. 2. The stretched polyolefin film according to claim 1, wherein, The polyolefin resin contains a polyethylene resin.
3. 3. The stretched polyolefin film according to claim 1, wherein, The stretched polyolefin film does not contain an inorganic antiblocking agent.
4. 4. The stretched polyolefin film according to claim 1, wherein, The stretched polyolefin film is a biaxially stretched film stretched in both the MD direction and the TD direction.
5. 5. The stretched polyolefin film according to any of claim 1 to 4, wherein, The stretched polyolefin film is used as a protective film for a laminated film.
6. 6. A protective film for a laminated film, wherein, The protective film for a laminated film comprising the stretched polyolefin film according to claim 5.
7. 7. A process for producing a stretched polyolefin film according to any one of claims 1 to 4, wherein, The method comprises a step of stretching a green sheet comprising the polyolefin resin in at least one of the MD direction and the TD direction, The preheating temperature of the blank sheet in the stretching treatment is 155 ℃ or more.

Description

Stretched polyolefin film, process for producing the same, and protective film for laminated film Technical Field The present invention relates to a stretched polyolefin film, a method for producing the same, and a protective film for a laminate film. Background Polyolefin films such as polyethylene films and polypropylene films are widely used in various fields such as packaging films and optical films, as well as protective films for electronic devices, and are extremely valuable materials. For example, a polyolefin film is known to be suitable as a protective film for a laminate film used in a lamination process (for example, patent document 1 and the like). Lamination is an indispensable technique for high integration of printed circuit boards. In this lamination process, a laminated film is attached to a circuit board, resin in the laminated film is cured by heat, then a through hole is formed by laser processing and the generated resin residue is removed, and then copper plating and patterning are performed. By repeating this operation, high integration of the printed circuit board is achieved. The laminated film used in the lamination process is formed of an adhesive layer containing a thermosetting resin such as an epoxy resin, and is an insulating material. A base film made of polyethylene terephthalate (PET) is provided on one surface of the adhesive layer, and a protective film made of the polyolefin film or the like is provided on the other surface. In the lamination process, the protective film provided on the laminate film is peeled off in advance to expose the adhesive layer (laminate film), and then the laminate film is bonded to the circuit board as described above. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2015-122372 Patent document 2 Japanese patent application laid-open No. 2019-163358 Disclosure of Invention Problems to be solved by the invention However, in order to prevent blocking of the film, an anti-blocking agent is contained in a usual polyolefin film (for example, patent document 2 described above). Therefore, the antiblocking agent sometimes falls off from the polyolefin film. The anti-blocking agent that has fallen off in this way may adhere to or migrate to other members, and may cause problems such as deterioration in performance of other members. For example, in the case of the above-described laminated film, if the protective film formed of the polyolefin film is peeled off from the laminated film (adhesive layer), the anti-blocking agent present in the polyolefin film may be peeled off and transferred to the adhesive layer. Since the anti-blocking agent is transferred to the adhesive layer, the thickness of the adhesive layer becomes uneven, with the problem that the insulation performance may be lowered. The present invention has been made in view of the above circumstances, and an object thereof is to provide a stretched polyolefin film capable of preventing blocking even if an anti-blocking agent is not contained, a method for producing the same, and a protective film for a laminated film. Means for solving the problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that the above object can be achieved by stretching in at least one axial direction of the MD direction and the TD direction, and by setting the degree of deviation (Ssk) of at least one surface measured in the surface roughness measurement to 1.0 or less and the height (Sk) of the core portion to 0.04 μm or more, and have completed the present invention. That is, the present invention includes, for example, the subject matter described in the following items. Item 1 A stretched polyolefin film comprising a polyolefin resin, wherein, The stretched polyolefin film is stretched in at least one axial direction of the MD direction and the TD direction, The stretched polyolefin film has a degree of deviation (Ssk) of 1.0 or less and a core height (Sk) of 0.04 [ mu ] m or more, as measured in surface roughness measurement. Item 2 The stretched polyolefin film according to item 1, wherein, The polyolefin resin contains a polyethylene resin. Item 3 The stretched polyolefin film according to item 1 or 2, wherein, The stretched polyolefin film does not contain an inorganic antiblocking agent. Item 4 The stretched polyolefin film according to any of the above 1 to 3, wherein, The stretched polyolefin film is a biaxially stretched film stretched in both the MD direction and the TD direction. Item 5 The stretched polyolefin film according to any of the above 1 to 4, wherein, The stretched polyolefin film is used as a protective film for a laminated film. Item 6 A protective film for a laminated film, wherein, The protective film for a laminated film comprising the stretched polyolefin film according to item 5. Item 7 A method for producing a stretched polyolefin film according to any one of items 1