JP2021055110A - Re-peelable surface protective film - Google Patents

Abstract

To provide a film that has excellent wet spread, can be pasted without causing wrinkling and bubbling in an object, and prevents whitening.SOLUTION: A re-peelable surface protective film has a base film, and an adhesive layer disposed on the base film. The base film is mainly composed of a vinylidene chloride copolymer. The adhesive layer is mainly composed of a polyurethane adhesive.SELECTED DRAWING: None

Description

The present invention relates to a removable surface protective film.

Surface protective films are used to protect various objects to protect the surface from dust, dirt, dirt and scratches.
For example, when forming an integrated circuit on a green sheet, there is a surface protective film for a green sheet that can be laminated or peeled to prevent impurities such as dust, dirt, and oil droplets from adhering to the green sheet and contaminating it (patented). Reference 1).
In addition, in order to protect optical members such as polarizing plates and wave plates, manufacturing processes and products of antistatic surface protective films and optical parts such as liquid crystal displays and touch panels of personal computers, televisions, mobile phones, etc. There is a surface protective film that protects the surface from dirt and scratches during package transportation and use (see, for example, Patent Documents 2 and 3).

Furthermore, in the medical field, since a personal computer for viewing electronic medical records and medical devices and medical devices are shared by a plurality of medical personnel, there is a concern about cross-infection, and it is required to maintain hygiene. Document 4 proposes a keyboard cover molded of a resin containing an antibacterial agent.

Japanese Unexamined Patent Publication No. H9-316411 Japanese Unexamined Patent Publication No. 2005-314476 Japanese Unexamined Patent Publication No. 2015-7226 Japanese Unexamined Patent Publication No. 2006-330954

Computers and medical devices have keyboards, switches, operation panels, etc., and have corners and irregularities. Therefore, when protecting these surfaces with a film, there are corners and irregularities. However, it is required that it is easy to attach, that is, it has wet spreadability and that it is hard to wrinkle. In addition, when the surface is covered with a film, it is required that bubbles cannot be formed.
If the wettability is insufficient, or if wrinkles or bubbles are present, the operability of the personal computer or medical device deteriorates, and smooth operation cannot be performed.
In addition, when a personal computer or medical device is covered with a surface protective film, the personal computer or device is operated through the film, so that the surface protective film changes color, etc. so that the object can be confirmed from the film. It is required to be kept transparent.

In the surface protection film for a green sheet described in Cited Document 1, an adhesive layer containing a crosslinked acrylic copolymer is laminated on one side of a biaxially stretched polyvinylidene chloride resin film.
In the surface protective film described in Cited Document 2, a pressure-sensitive adhesive layer formed by cross-linking a pressure-sensitive adhesive composition containing a (meth) acrylic monomer on a support made of an antistatic-treated plastic base material is formed. There is.
In the surface protection film described in Cited Document 3, an adhesive layer of a removable urethane pressure-sensitive adhesive composition containing a polyurethane resin is formed on a plastic film base material.
However, all of the surface protection films described in the cited documents 1 to 3 are used to prevent the object coated on the film from being scratched or soiled, and are covered with the film. It is not premised that the broken object is operated from above the film, and the operability of the object covered with the film is not excellent.

Therefore, an object of the present invention is to provide a film having excellent wettability and spreading property, which can be attached to an object without wrinkles or bubbles, and which is less likely to cause whitening.

As a result of diligent research, the present inventors have made a film having a base film containing a specific polymer and a pressure-sensitive adhesive layer containing a specific pressure-sensitive adhesive arranged on the base film as an object. We have found that when the film is attached, it has excellent wettability and spreadability, does not generate wrinkles or bubbles, is less likely to cause whitening, and maintains the transparency of the film, and has completed the present invention.

That is, the present invention is as follows.

[1]
Base film and
With the adhesive layer arranged on the base film,
It is a removable surface protective film having
The base film contains a vinylidene chloride copolymer as a main component.
The adhesive layer contains a polyurethane adhesive as a main component.
Removable surface protective film.
[2]
The removable surface protective film according to [1], wherein the adhesive strength of the adhesive film is 0.03 to 0.30 N / 25 mm.
[3]
The base film has a thickness of 10 to 30 μm and has a thickness of 10 to 30 μm.
The 2% strain elastic modulus in the flow direction (MD direction) and the 2% strain elastic modulus in the width direction (TD direction) are 190 to 400 MPa, respectively, and
The tensile elongation in the flow direction (MD direction) and the width direction (TD direction) satisfy 80 to 150%, respectively.
The removable surface protective film according to [1] or [2].
[4]
The removable surface protective film according to any one of [1] to [3], wherein 40 to 80% of the epoxidized vegetable oil and 40 to 80% of the fatty acid glycerin ester are contained in the adhesive layer. Removable surface protective film.
[5]
The removable surface protective film according to any one of [1] to [4], wherein the pressure-sensitive adhesive layer has a thickness of 1.0 to 30 μm.
[6]
The removable surface protective film according to any one of [1] to [5], wherein the polyurethane adhesive contains a polyurethane having a hydroxyl group as a main agent and an aliphatic diisocyanate as a curing agent.
[7]
A removable surface protective film winding body comprising a cylindrical winding core and the removable surface protective film according to any one of [1] to [6] wound around the winding core.
[8]
The removable surface protective film according to any one of [1] to [6], which is used for protecting medical devices.

The removable surface protective film of the present invention has excellent wettability and spreadability when attached to an object, and the generation of wrinkles and bubbles is suppressed. Further, the removable surface protective film of the present invention is less likely to cause whitening, and the transparency of the film is maintained. Therefore, especially when used to protect personal computers and medical devices in the medical field, cross-infection can be prevented in a usage environment where multiple medical personnel indirectly contact, and personal computers and medical devices can be prevented from the film. Can be operated.

It is the schematic which shows the removable surface protection film of this embodiment.

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and the present invention is not intended to be limited to the present embodiment. Then, the present invention can be appropriately modified and implemented within the scope of the gist thereof.

<Removable surface protective film>
The removable surface protective film of the present embodiment includes a base film, an adhesive layer arranged on the base film, and the like.
Have. Further, the base film contains a vinylidene chloride copolymer as a main component, and the pressure-sensitive adhesive layer contains a polyurethane pressure-sensitive adhesive as a main component.
The removability means a property that the film can be peeled off after being attached to the object once. Further, the removability is derived from the adhesive layer in the present embodiment.

(Base film)
The base film in the present embodiment contains a vinylidene chloride copolymer as a main component.
The base film in the present embodiment contains 100 parts by mass of a vinylidene chloride copolymer containing 75 to 96% by mass of a vinylidene chloride monomer unit and having a weight average molecular weight of 7 × 10 ^{4 to} 14 × 10 ^{4 g / mol.} , 1 to 20 parts by mass of a mixture of fatty acid esters and epoxidized compounds. The mixture of the fatty acid ester and the epoxidized compound is more preferably 1 to 15 parts by mass and further preferably 1 to 10 parts by mass with respect to 100 parts by mass of the vinylidene chloride copolymer.
Further, the base film in the present embodiment may contain a resin other than the vinylidene chloride copolymer, but the resin contained in the base film is preferably made of a vinylidene chloride copolymer.

The thickness of the base film in the present embodiment is preferably 5 to 45 μm, more preferably 10 to 30 μm, and further, from the viewpoint of wettability and spreadability, operability and durability of a personal computer or medical device. It is preferably 15 to 30 μm.

Further, the base film in the present embodiment has a 2% strain elastic modulus in the flow direction (MD direction) and a 2% strain elastic modulus in the width direction (TD direction) of 190 to 400 MPa, respectively, and the flow direction. It is preferable that the tensile elongations in the (MD direction) and the width direction (TD direction) satisfy 80 to 150%, respectively.
In the removable surface protective film of the present embodiment, the 2% strain elastic modulus of the base film is 190 to 400 MPa, so that the film is difficult to stretch and tends not to be torn.
In the removable surface protective film of the present embodiment, since the tensile elongation of the base film is 80 to 150%, the film is difficult to stretch and tends not to be torn.

The base film used in the present embodiment has a 2% strain elastic modulus in the flow direction (MD direction) of more preferably 190 to 350 MPa, further preferably 200 to 300 MPa.
Further, the base film used in the present embodiment has a 2% strain elastic modulus in the width direction (TD direction) of more preferably 190 to 350 MPa, further preferably 190 to 300 MPa.

Further, the base film used in the present embodiment has a tensile elongation in the flow direction (MD direction) of 90 to 140%, more preferably 90 to 130%.
Further, the base film used in the present embodiment has a tensile elongation in the width direction (TD direction) of more preferably 80 to 140%, further preferably 90 to 130%.

When a base film having such characteristics is used, the removable surface protective film tends to be more difficult to stretch and torn even when repeatedly key-touched, for example, when used as a keyboard cover. Further, the corners of various devices are also difficult to stretch and tear, so that they can be used to protect the devices. Various devices include, for example, multifunction devices in offices, weighing machines in retail cash register and backyard, switches and operation panels for inspection equipment such as MRI and CT in hospitals, electronic medical record wagons, stretchers, etc. The equipment to have is mentioned.

The method for controlling the 2% strain elastic modulus and tensile elongation of the base film within the above ranges is not particularly limited, and is, for example, a step of extruding a resin and a plasticizer from an annular die as a single layer or a multilayer raw fabric, and extruding. Examples of the method include a step of cooling and solidifying the cooled and solidified raw fabric and a step of stretching the cooled and solidified raw fabric.

Further, the base film is preferably stretched. The stretching treatment step is a known step of performing a stretching treatment in the uniaxial or biaxial direction with respect to the original film. The stretching method is not limited, and biaxial stretching is preferable, and sequential or simultaneous biaxial stretching method or inflation biaxial stretching method can be adopted, and among these, the inflation biaxial stretching method is preferable.

In this embodiment, the 2% strain elastic modulus and tensile elongation of the base film can be measured by the methods described in Examples described later.

(Adhesive layer)
The pressure-sensitive adhesive layer in the present embodiment contains a polyurethane pressure-sensitive adhesive as a main component and is a layer formed by such a polyurethane pressure-sensitive adhesive.
The main component of the adhesive layer in the present embodiment means a component of 70% by mass or more, preferably 75% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass when all the components are 100% by mass. It is 100% by mass or more, more preferably 100% by mass.

The polyurethane pressure-sensitive adhesive is not particularly limited as long as it contains polyurethane and a curing agent. In addition, polyurethane pressure-sensitive adhesives include coupling agents, plasticizers, terpene-based and rosin-based pressure-sensitive adhesives, inorganic fillers such as calcium carbonate and titanium oxide, antioxidants, ultraviolet absorbers, etc. as other additives. Stabilizers and the like may be contained.

The polyurethane is not particularly limited as long as it is a polymer having a urethane bond, and for example, polyurethane having a hydroxyl group and the like can be preferably mentioned. Specific examples of the polyurethane having a hydroxyl group include a polymer of an isocyanate compound and a polyol.

Examples of the isocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene diisocyanate, phenylenediisocyanate, triphenylmethane triisocyanate, and polyphenylpolymethylene polyisocyanate; hexamethylene diisocyanate, Lipid or alicyclic polyisocyanates such as lysine diisocyanate, cyclohexanediisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate; polyisocyanate having carbodiimide group; polyisocyanate having allophanate group; isocyanurate group Polyisocyanate having the above; and the like. These may be used alone or in combination of two or more.

Examples of the polyol include a polyether polyol, a polyester polyol, a polyether ester polyol, and the like. These may be used alone or in combination of two or more.

As the polyester polyol, one obtained by reacting a polycarboxylic acid with a polyol can be used.
Examples of the polycarboxylic acid include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecandicarboxylic acid and other aliphatic polycarboxylic acids, and o-phthalic acid and other aromatic fragrances. Group polycarboxylic acids and the like can be used.
Examples of polyols that can be used for producing polyester polyols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, and 2,2-dimethyl. -1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexane-1,4-diol , Cyclohexane-1,4-dimethanol and the like can be used.
Further, as the polyester polyol, a ring-opening polymer such as γ-butyrolactone or ε-caprolactone, poly (hexamethylene carbonate) diol or the like can also be used.

Examples of the polyether polyol include those obtained by ring-opening polymerization of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran and the like using the above-mentioned polyol, polyamine and the like as an initiator.

Examples of the polyester ether polyol include the above-mentioned copolymers of the polyester polyol and the polyether polyol.

Further, as the polyol used for producing the polyurethane having a hydroxyl group, a low molecular weight polyol having a molecular weight of 60 to 140 can also be used.
Examples of low molecular weight polyols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, and 2,2-dimethyl-1,3-. Propylene diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, Cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, sorbitol, methylglycoside and the like can be mentioned.

The polyurethane having a hydroxyl group may be a polyurethane produced by using an amine compound as a chain extender in addition to the above-mentioned polyol compound.
Examples of the amine compound include diamines such as ethylenediamine, hexamethylenediamine and piperazin; aminoalcohols such as monoethanolamine and diethanolamine; and the like.

As the polyurethane having a hydroxyl group, a commercially available product can be used, and examples of the commercially available product include Toyochem SH-101 and the like.

Examples of the curing agent include aromatic diisocyanates such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI) and xylene diisocyanate (XDI), and aliphatic diisocyanates such as hexamethylene diisocyanate (HDI). .. These may be used alone or in combination of two or more.
Among the above-mentioned curing agents, an aliphatic diisocyanate is preferable.
As the curing agent, a commercially available product can be used, and examples of the commercially available product include Toyochem T501B and the like.

In the polyurethane pressure-sensitive adhesive, the curing agent is preferably 0.1 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 4.0% by mass with respect to the mass of the polyurethane pressure-sensitive adhesive. Contains 6.0% by mass.
By setting the amount of the curing agent to 0.1% by mass or more, curing tends to proceed appropriately and no adhesive residue is generated during use. Further, by setting the amount of the curing agent to 10% by mass or less, the desired adhesive performance can be obtained.

Having an adhesive layer formed of the adhesive as described above, the removable surface protective film of the present embodiment firmly adheres to the medical device when used as a cover of the medical device, and when peeled off, for example. The effect of being easily peeled off appears. In addition, the film is not entangled and is easy to handle.

The thickness of the adhesive layer in the present embodiment is preferably 0.5 to 40 μm, more preferably 1.0 to 30 μm, and 3.0 to 25 μm from the viewpoint of the adhesive strength of the adhesive layer. It is even more preferably 5.0 to 25 μm.
When the thickness of the adhesive layer is within the above range, the removable surface protective film of the present embodiment is said to be firmly attached to the medical device when used as a cover of the medical device and easily peeled off when the adhesive layer is peeled off. The effect is further exhibited. In addition, the film is not entangled and is easier to handle.
Further, by setting the thickness of the adhesive layer in the present embodiment within the above range, the amount of the epoxidized vegetable oil and the fatty acid glycerin ester contained in the adhesive layer can be controlled.

The removable surface protective film of the present embodiment includes an adhesive layer, and the adhesive force of the adhesive layer (JIS0237 compliant 180 degree peeling force) is preferably 0.01 to 0.40 N / 25 mm. The adhesive strength is more preferably 0.02 to 0.30 N / 25 mm, and even more preferably 0.03 to 0.30 N / 25 mm. The removable surface protective film contains an adhesive layer having an adhesive strength of 0.01 to 0.40 N / 25 mm, so that, for example, when used as a cover for a medical device, it firmly adheres to the medical device and when peeled off. It has the effect of being easily peeled off. Further, by performing a slight adhesive process on the above-mentioned base film with the adhesive layer, the films can be easily handled without being entangled with each other when the films are attached. Further, since the removable surface protective film contains an adhesive layer having an adhesive force of 0.01 to 0.40 N / 25 mm, it tends to be possible to suppress the generation of wrinkles and bubbles when the film is attached.

The method for controlling the adhesive strength of the adhesive layer within the above range is not particularly limited, but for example, a method for adjusting the hardness of the adhesive and the thickness of the adhesive layer, and adjusting the epoxidized vegetable oil and the fatty acid glycerin ester contained in the adhesive layer. The method of doing this can be mentioned.

In the present embodiment, the adhesive force of the adhesive layer is a 180-degree peeling force obtained by a measurement method based on JIS0237. Further, the adhesive strength of the adhesive layer can be specifically measured by the method described in Examples.

The adhesive layer in the present embodiment preferably contains 40 to 80% of the epoxidized vegetable oil contained in the removable surface protective film and 40 to 80% of the fatty acid glycerin ester.
The ratio of the epoxidized vegetable oil and the fatty acid glycerin ester in the adhesive layer is more preferably 40 to 70%, further preferably 40 to 60%.
Since the upper limit of the epoxidized vegetable oil and the fatty acid glycerin ester is 80%, the adhesive layer has sufficient adhesive strength, and for example, when used as a cover of a medical device, it firmly adheres to the medical device. Can be done.
When the lower limit of the epoxidized vegetable oil and the fatty acid glycerin ester is 40%, it is possible to maintain an appropriate elasticity of the base film.

The method for controlling the amounts of the epoxidized vegetable oil and the fatty acid glycerin ester in the pressure-sensitive adhesive layer is not particularly limited, but for example, the method for adjusting the hardness of the pressure-sensitive adhesive and the thickness of the pressure-sensitive adhesive layer, and the amount of the curing agent are adjusted. The method and the like can be mentioned.

The amounts of the epoxidized vegetable oil and the fatty acid glycerin ester in the adhesive layer can be specifically measured by the method described in Examples.

(Release layer)
The removable surface protective film of the present embodiment may further include a release layer on the back surface (the surface on which the adhesive layer is not laminated) of the base film. When the removable surface protective film of the present embodiment contains a release layer, the removable surface protective film tends to be easily unwound when the removable surface protective film is used as a wound body.
The release layer is not particularly limited, but for example, a silicone type or a long-chain alkyl pendant polymer type can be used.
The thickness of the release layer is preferably 0.1 to 1.0 μm, more preferably 0.15 to 0.9 μm, and even more preferably 0.2 to 0.7 μm.
Furthermore, the removable surface protective film of the present embodiment may be provided with a printing layer or a primer layer between the base film and the adhesive layer.

(separator)
The removable surface protective film of the present embodiment may further have a separator on the pressure-sensitive adhesive layer side of the layer including the base film and the pressure-sensitive adhesive layer, that is, on the pressure-sensitive adhesive layer. The separator is not particularly limited, and for example, polyethylene terephthalate (PET) film or paper whose releasability is exhibited by silicone treatment can be used.

One aspect of the removable surface protective film of the present embodiment is shown as a schematic view in FIG.
Specifically, the removable surface protective film of the present embodiment is represented by 1 of the surface protective film, as shown in FIG.
Includes base film 2, adhesive layer 3, release layer 4, and separator 5.
The adhesive layer 3 is laminated on the first surface of the base film 2, and the release layer 4 is laminated on the second surface.
It has a structure in which a separator 5 is laminated on the adhesive layer 3.

<Manufacturing method of removable surface protective film>
The method for producing the removable surface protective film of the present embodiment is not particularly limited as long as the adhesive layer can be laminated on the base film. Further, the base film in the present embodiment is, for example, a step of extruding a resin and a plasticizer from a cyclic die as a single-layer or multilayer raw fabric, a step of cooling and solidifying the extruded raw fabric, and cooling and solidifying. It can be produced by a method including a step of stretching the raw fabric.

The stretching treatment step is a known step of performing a stretching treatment in the uniaxial or biaxial direction with respect to the original film. The stretching method is not limited, and biaxial stretching is preferable, and sequential or simultaneous biaxial stretching method or inflation biaxial stretching method can be adopted, and among these, the inflation biaxial stretching method is preferable.

The removable surface protective film of the present embodiment is, for example, a base film obtained as described above, coated with an adhesive with a comma coater or a gravure coater, dried, wound, and aged at 40 ° C. for 2 days. Obtainable. At that time, a method of applying an adhesive to the separator, drying the separator, and then laminating the base film may be used. Before applying the pressure-sensitive adhesive, a primer having an affinity between the pressure-sensitive adhesive layer and the base material layer may be applied in advance, or the base material film may be subjected to corona treatment. In addition, the back surface of the base material may be treated in the steps before and after the pressure-sensitive adhesive coating.

<Removable surface protective film winding body>
The removable surface protective film of the present embodiment may be a removable surface protective film winding body, and such a removable surface protective film is a core tube and the above-mentioned releasable surface wound around the core tube. Provided with a protective film.

The material of the core tube is not limited, and for example, a core tube made of paper, plastic, metal, or the like can be used. The core tube may be a cylindrical object having a hollow inside or a cylindrical object that is not hollow. Further, the diameter of the core tube is not limited, and may be, for example, 10 mm to 50 mm.

In the removable surface protective film wound body of the present embodiment, the pulling output for pulling out the removable surface protective film from the core tube is preferably 30 to 300 cN / 200 mm width, and is 35 to 200 cN / 200 mm width. It is more preferable to have a width of 40 to 100 cN / 200 mm. By setting the pulling output within the above range, a required amount of removable surface protective film can be pulled out with a light force.

The method of controlling the pulling output for pulling out the removable surface protective film from the core tube within the above range is not particularly limited, but for example, in addition to setting the adhesive strength of the releasable surface protective film, the releasable surface protection A method of providing a release layer on the back surface of the film can be mentioned.

In this embodiment, the pulling output for pulling out the removable surface protective film from the core tube can be measured by the method described in Examples described later.

<Removable surface protection film storage box>
The removable surface protective film winding body may be stored in a box (hereinafter, also referred to as “removable surface protective film storage box”).
The removable surface protective film storage box includes means for pulling out the removable surface protective film from the core tube. Removable surface protection film The required amount of film can be pulled out by providing a take-out port for pulling out the winding body and making the winding body freely rotatable in the storage box.
Further, the removable surface protective film storage box can be provided with means for cutting the removable surface protective film drawn from the core tube. As a result, the required amount of the removable surface protective film drawn out can be easily cut. As a means for cutting, a slide cutter may be used in addition to a saw blade made of metal, paper, plastic or the like.

<Use of removable surface protective film>
The removable surface protective film of the present embodiment can be used for protection of medical devices. Here, the objects such as medical devices include, for example, switches and operation panels of inspection devices such as MRI and CT, examination tables, electronic medical record wagons, stretchers, personal computers, offices, etc. in medical institutions such as hospitals. Examples include equipment, appliances, equipment, furniture, and office furniture used in medical institutions such as copy machines. In addition to medical institutions, for example, equipment such as cash registers in retail stores, weighing machines in backyards and food processing plants, filling machines, workbenches, mobile trolleys, electronic equipment on the surface of building materials and construction sites, and construction machinery. It can be used without restrictions for applications other than medical institutions such as operation panels.

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 as long as the gist of the present invention is not exceeded.

Each measurement method used in Examples and Comparative Examples was as follows.

(1) The 2% strain elastic modulus of the base film was measured according to ASTM-D882. That is, the base film of each example was cut out into a sample having a width of 10 mm and a length of 100 mm, respectively, along the MD and TD directions, and measurement was performed at a tensile speed of 5 mm / min. Draw a tangent line on the obtained stress-strain graph, calculate the value obtained by converting the stress value at 2% elongation into the thickness of the sample, and use the average value of the five measurements as the measured value, in the MD direction and the TD direction. The average value of 2% strain elastic modulus was used. As the measuring device, AUTOGRAPH AG-IS manufactured by Shimadzu Corporation was used.

(2) The tensile elongation of the base film was measured according to ASTM-D882. That is, the base film of each example was cut into a sample having a width of 10 mm and a length of 100 mm, respectively, along the MD and TD directions, measured at a tensile speed of 300 mm / min, and the elongation at break was 5 The average value of the measurements was taken as the measured value, and the average value in the MD direction and the TD direction was used as the tensile elongation value. For the measurement, AUTOGRAPH AG-IS manufactured by Shimadzu Corporation was used.

(3) Adhesive Strength of Adhesive Layer The adhesive strength of the adhesive layer was measured as follows in accordance with JISZ0237. That is, the film was cut out along the MD direction to a width of 25 mm and a length of 300 mm to prepare a sample, and the film was attached to the SUS304 plate mirror finish by reciprocating twice at 10 mm / sec using a 2 kg weight roller. The tensile measurement was performed at a speed of 300 mm / min, and the average value of the peeling force measured 5 times was taken as the value of the adhesive force. For the measurement, AUTOGRAPH AG-IS manufactured by Shimadzu Corporation was used. The 180-degree peeling force thus obtained was taken as the adhesive force of the adhesive layer.

(4-1) Thickness of base film The film was cut using a microtome, and the cut surface was observed with an optical microscope (Keyence VHX-900) to measure the thickness of the base film. This was further measured every 1 m in the MD direction (unwinding direction) of the film, and finally, the average value of 10 points was taken as the thickness of the base film.

(4-2) Thickness of Adhesive Layer The removable surface protective film was cut using a microtome, and the cut surface was observed with an optical microscope (Keyence VHX-900) to measure the thickness of the adhesive layer. This was further measured every 1 m in the MD direction (unwinding direction) of the film, and finally, the average value of 10 points was taken as the thickness of the adhesive layer.

(5) Content of epoxidized vegetable oil and content of glycerin fatty acid ester The removable surface protective film can be made into a base film and an adhesive by peeling the adhesive layer of the removable surface protective film with a spatula. , Separated, each dissolved in hexafluoro-2-propanol (HFIP), extracted, and dried. Each is dissolved in d8-tetrahydrofuran (THF), NMR is measured, and ¹ H-NMR spectrum is epoxidized by the internal standard method (internal standard substance; N, N-dimethylformamide (DMF)) from the signal analysis value. The content of vegetable oil and the content of glycerin fatty acid ester were quantified. The value of the content obtained from the pressure-sensitive adhesive was taken as the content of the epoxidized vegetable oil contained in the pressure-sensitive adhesive layer and the content of the glycerin fatty acid ester.

(6) Wet-spreading property Wetting-spreading property was evaluated by the time required for wet-spreading.
A removable surface protective film was cut into 20 cm squares, one piece was attached to a glass plate, and both ends of the one piece were held by hand and pulled to make the film wrinkle-free, and then released. ..
<Evaluation criteria>
⊚: The time required for wetting and spreading was less than 5 seconds.
◯: The time required for wetting and spreading was 5 seconds or more and less than 10 seconds.
Δ: The time required for wetting and spreading was 10 seconds or more.
X: The removable surface protective film did not adhere to the glass plate.

(6) Presence or absence of bubbles Cut out a removable surface protective film into 20 cm squares, attach one piece to a glass plate, hold both ends of the piece with your hands and pull to make the film wrinkle-free, and then put your hands on it. Separated and pasted.
<Evaluation criteria>
⊚: There were no bubbles between the film and the glass plate.
◯: There were 1 or 2 bubbles between the film and the glass plate.
Δ: There were 3 to 5 bubbles between the film and the glass plate.
X: There were 5 or more bubbles between the film and the glass plate.

(7) Presence or absence of wrinkles Cut out a removable surface protective film into 20 cm squares, attach one piece to a glass plate, hold both ends of the other piece by hand and pull to make the film wrinkle-free, and then release it. After pasting, it was crimped with the palm of the hand.
<Evaluation criteria>
⊚: There were no wrinkles.
◯: There were 1 or 2 wrinkles.
Δ: There were 3 to 5 wrinkles.
X: There were 6 or more wrinkles.

(8) Presence or absence of whitening A removable surface protective film was attached to the keyboard, and the keys were repeatedly touched to evaluate by typing 20,000 random Japanese sentences.
<Evaluation criteria>
⊚: No whitening.
〇: Whitened, but the characters were visible.
Δ: Whitened and the characters could not be seen.
X: Whitened and powder was generated.

[Example 1]
[Manufacturing of base film]
A base film (PVDC film, thickness: 21 μm) containing a vinylidene chloride copolymer (PVDC) as a main component was produced as follows.
Vinylidene chloride-vinyl chloride copolymer (vinylidene chloride monomer unit content / vinyl chloride monomer unit content = 80% by mass / 20% by mass, weight average molecular weight 120,000, expressed as "PVDC" in Table 1 ) To 100 parts by mass, add 3 parts by mass of dibutyl sebacate as fatty acid esters, 3 parts by mass of acetyltributyl citrate, and 2 parts by mass of epoxidized soybean oil as an epoxidized compound, and mix with a Henschel mixer for 5 minutes. did. The obtained mixture is extruded into a tubular shape by a melt extruder, supercooled in a cold water tank at about 10 ° C., passed through water at 35 ° C., a stretching temperature of 30 ° C., 3.0 times in the longitudinal (MD) direction, and a width (TD). A tubular film obtained by performing 4.0-fold inflation biaxial stretching in the direction of) was folded with a pinch roll to prepare a flat elongated film having a thickness of 42 μm. Then, it was peeled off into a single film using a slitter to obtain a 21 μm film. The characteristics of the obtained film (base film) were measured by the above method. The measurement results are shown in Table 1.

[Manufacturing of removable surface protective film]
Urethane 1 (main agent: Toyochem SH-101 (100 parts by mass), curing agent: Toyochem-T501B (5 parts by mass)), which is a urethane adhesive, is added to a separator (silicone-treated polyethylene terephthalate (PET) film) to a thickness of 15 μm. Then, the coating was applied using a comma coater, and the base film produced above was laminated and wound up. Next, a 1.5% solution of a back treatment agent (Lion Specialty Chemicals Pyroyl 1050) was applied to the surface of the base film with a gravure coater having a plate size of 18 μm and wound up. After aging this at 40 ° C. for 3 days, a removable surface protective film was produced by delaminating the separator. The obtained removable surface protective film was aged at 28 ° C. for 1 month, and then the characteristics were measured as described above. The measurement results are shown in Table 1.

[Example 2]
As the adhesive, urethane 2 (main agent: Toyochem SH-101 (100 parts by mass), curing agent: Toyochem-T501B (6 parts by mass)) was used instead of urethane 1, and the thickness of the adhesive layer was set to 20 μm. A removable surface protective film was produced in the same manner as in Example 1 except for the above.

[Example 3 and Example 4]
A removable surface protective film was produced in the same manner as in Example 1 except that the thickness of the base film and the thickness of the adhesive layer were changed as shown in Table 1.

[Example 5]
A removable surface protective film was produced in the same manner as in Example 1, and the obtained film was aged at 40 ° C. for 1 month to obtain a removable surface protective film.

[Example 6]
A removable surface protective film was produced in the same manner as in Example 1, and the obtained film was aged at 15 ° C. for 1 month to obtain a removable surface protective film.

[Comparative Example 1]
As the pressure-sensitive adhesive, acrylic 1 (main agent: Saiden Chemical MS3999 (100 parts by mass), curing agent: Saiden Chemical K315 (1.5 parts by mass)), which is an acrylic pressure-sensitive adhesive, was used instead of urethane 1. , A removable surface protective film was produced in the same manner as in Example 1.

[Comparative Example 2]
Example 1 except that acrylic 2 (main agent: Lion Specialty Chemicals AS665 (100 parts by mass), curing agent: Lion Specialty Chemicals B-45 (5 parts by mass)) was used as the base material instead of urethane 2. A removable surface protective film was produced in the same manner as in the above.

[Comparative Example 3]
A removable surface protective film was produced in the same manner as in Example 1 except that a polyethylene resin was used instead of the vinylidene chloride copolymer as the base material. The obtained removable surface protective film did not contain plasticizers such as fatty acid esters and epoxidized compounds.

[Comparative Example 4]
A removable surface protective film was produced in the same manner as in Example 2 except that a polyethylene resin was used instead of the vinylidene chloride copolymer as the base material. The obtained removable surface protective film did not contain plasticizers such as fatty acid esters and epoxidized compounds.

The characteristics of the obtained removable surface protective film were measured as described above. The measurement results are shown in Table 1.

In the table, N / A indicates that the measurement data was not obtained.

The removable surface protective film of the present invention is used for various inspection devices having an electronic medical record keyboard and an operation panel that are contacted by a plurality of medical personnel in a hospital, and is used for adhesion of bacteria and viruses, blood, vomitus, and other body fluids. It can prevent adhesion and prevent cross-infection between medical personnel. Further, the removable surface protective film of the present invention can be used for protection of devices, particularly medical devices, because it is also difficult to stretch and tear at the corners of various devices. Therefore, the removable surface protective film of the present invention has industrial applicability as a surface protective film for devices and devices used in the medical field.

1: Surface protection film 2: Base film 3: Adhesive layer 4: Release layer 5: Separator

Claims (7)

Base film and
With the adhesive layer arranged on the base film,
It is a removable surface protective film having
The base film contains a vinylidene chloride copolymer as a main component.
The adhesive layer contains a polyurethane adhesive as a main component and contains
The adhesive layer contains 40 to 80% of the epoxidized vegetable oil and 40 to 80% of the fatty acid glycerin ester contained in the removable surface protective film.
Removable surface protective film. The removable surface protective film according to claim 1, wherein the adhesive strength of the adhesive film is 0.03 to 0.30 N / 25 mm. The base film has a thickness of 10 to 30 μm and has a thickness of 10 to 30 μm.
The 2% strain elastic modulus in the flow direction (MD direction) and the 2% strain elastic modulus in the width direction (TD direction) are 190 to 400 MPa, respectively, and
The tensile elongation in the flow direction (MD direction) and the width direction (TD direction) satisfy 80 to 150%, respectively.
The removable surface protective film according to claim 1 or 2. The removable surface protective film according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer has a thickness of 1.0 to 30 μm. The removable surface protective film according to any one of claims 1 to 4, wherein the polyurethane pressure-sensitive adhesive contains a polyurethane having a hydroxyl group as a main agent and an aliphatic diisocyanate as a curing agent. A removable surface protective film winding body comprising a cylindrical winding core and a removable surface protective film wound around the winding core according to any one of claims 1 to 5. The removable surface protective film according to any one of claims 1 to 5, which is used for protecting a medical device.

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