JP2012017417A - Protective film and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective film excellent in heat-resistant dimensional stability, free from peeling or rising after being stuck to an adherend, and particularly suitable for application to optical components.SOLUTION: The protective film comprises an adhesive layer laminated on one surface of a base film formed of an α-olefin resin composition which contains: an α-olefin resin containing 60 wt.% or more of at least one kind selected from a group consisting of a propylene single polymer and a copolymer of 90 mol% or more of propylene and 10 mol% or less of another α-olefin; and 100 to 1,000 ppm of a specified compound represented by 1,2,3-propane tricarboxylic acid tri(2-methylcyclohexylamide).

Description

  The present invention relates to a protective film and a manufacturing method thereof. More particularly, the present invention relates to a protective film that is preferably used for protecting the surface of an optical component and a method for manufacturing the same.

In order to protect the surface of the product from scratches, dirt, etc. during the manufacture and transfer and storage of steel plates, resin plates, automobiles, optical parts, etc., a protective film is applied to the product surface for protection. To be done.
In recent years, there has been an increasing demand for surface protection films for optical parts, particularly various parts in the field related to liquid crystal displays. Since optical parts such as liquid crystal displays are manufactured by combining many flat parts, the surface of each part is required to have a very high level of smoothness. You should avoid it as much as possible. In the production of these optical parts, the surface protection film is immediately applied under clean conditions after production to protect the parts produced in each process from scratches and dirt until they are delivered to the next process. It is affixed, stored and transported in that state, and optical inspection of component specifications is also performed with a protective film affixed. Once the surface protective film is pasted, it is strictly required that the surface protective film is not peeled inadvertently before it is delivered to the manufacturing process of the part, the storage of the part, and the next process after the protective film is pasted. This peeling shows a state where the protective film at the end of the component is peeled off, or a state where the protective film is floated at a portion other than the end of the component and bubbles are generated. When it peels off, naturally the original function as a protective film cannot be expressed at all. Further, such a protective film is required to have as few fish eyes as possible so as not to hinder the optical inspection.

Such a protective film is usually produced by laminating an adhesive layer on one side of a base film made of resin. Here, in order to laminate the pressure-sensitive adhesive, after the pressure-sensitive adhesive is applied on one surface of the base film, the pressure-sensitive adhesive is cured and heated to about 80 to 100 ° C. in a drying furnace and the pressure-sensitive adhesive. A step of adhering the layer to the base film is performed. In this step, since heating is performed in a state in which the base film is subjected to a tension by a processing machine (roll) and a load due to the weight of the film, the base film may be distorted or deformed. When used, it may contribute to peeling of the film.
The protective film after manufacture is used at the time of use, that is, after being attached to an adherend such as an optical component, and then, for example, at a temperature of about 100 to 150 ° C. according to a request in manufacture of the adherend itself (for example, annealing of the device). There are cases where heating is performed, and at this time, the base film may be distorted and cause peeling.
In order to suppress distortion or deformation of the base film, Patent Document 1 proposes that a specific cyclic organophosphate compound is contained in the resin constituting the base film. According to this technology, although distortion of the base film in the process of laminating the adhesive layer on one side of the base film is improved, distortion that cannot be overlooked in the base film occurs during heating after application to the adherend. In addition, the protective film is liable to be lifted or peeled off.

Moreover, although patent document 2 is related with the invention of the separator film for film tacks, it is demonstrated that the polypropylene film manufactured through the biaxial stretching process is excellent in the dimensional stability in a dry printing process. However, if this technology is applied to a protective film for optical parts, the substrate film will be greatly distorted by heating after being applied to the adherend, and the biaxially stretched film has a polarizing property. As a protective film for optical parts accompanied with, it cannot be used from the beginning.
Under the circumstances as described above, a protective film that can be suitably used particularly for protecting the surface of optical components is eagerly desired.

JP 2007-270005 A JP-A-11-279497 JP 2000-25108 A

  The present invention has been made in view of the above circumstances, and the object thereof is excellent in heat-resistant dimensional stability, and does not cause peeling and floating after being attached to an adherend, particularly in application to optical components. It is in providing a suitable protective film and its manufacturing method.

In order to achieve the above object, the present inventors have clarified the range of heat-resistant dimensional stability that the base film of the protective film should have, and searched for a resin composition and a film forming method that exhibit such heat-resistant dimensional stability. Went. As a result, a film formed without stretching from a resin composition containing a specific proportion of an α-olefin resin and a specific nucleating agent in a certain ratio is specifically excellent in heat-resistant dimensional stability. The present invention has been completed by finding that it exhibits excellent properties and is excellent in other properties required for protective film applications.
That is, according to the present invention, the above objects and advantages of the present invention are as follows.
An α-olefin resin containing at least 60% by weight of at least one selected from the group consisting of a homopolymer of propylene and a copolymer of 90 mol% or more of propylene and 10 mol% or less of another α-olefin, and The following general formula (1)

(In the formula (1), R ¹ is a propane-1,2,3-triyl group or a butane-1,2,3,4-tetrayl group,
R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms,
K is 3 when R ¹ is a propane-1,2,3-triyl group;
When R ¹ is a butane-1,2,3,4-tetrayl group, k is 4, and a plurality of R ² may be the same or different. )
100 to 1,000 ppm of a compound represented by
A protective film formed by laminating an adhesive layer on one side of a base film made of an α-olefin resin composition containing
The first dimensional change rate after the test piece obtained by cutting the base film to 300 mm (MD direction) × 100 mm (TD direction) at 80 ° C. for 10 minutes under a load of 1,000 g is the initial With respect to the value, it is 2.5% or less in the MD direction and 1.2% or less in the TD direction, and the test piece after measuring the first dimensional change rate is further subjected to 15 minutes at 100 ° C. under no load. The second dimensional change rate after standing is 1.2% or less in the MD direction and 0.8% or less in the TD direction with respect to the test piece after the first dimensional change rate measurement. This is achieved by the protective film.
Second, the above objects and advantages of the present invention are:
An α-olefin resin containing at least 60% by weight of at least one selected from the group consisting of a homopolymer of propylene and a copolymer of 90 mol% or more of propylene and 10 mol% or less of another α-olefin, and 100 to 1,000 ppm of the compound represented by the general formula (1)
A non-stretched α-olefin resin composition containing a base film,
This is achieved by a method for producing the protective film, which comprises a step of laminating an adhesive or the like on one side of the base film to form a laminated film, and heating the laminated film at 80 to 100 ° C.

Since the protective film of the present invention is excellent in heat-resistant dimensional stability, even if it is heated after being attached to an adherend, it does not peel and / or float, and is particularly suitable for use as a protective film for optical components. Can do.
Such a protective film of the present invention can be easily produced by the method of the present invention as described above.

<Base film>
The base film in the protective film of the present invention is
At least one selected from the group consisting of a homopolymer of propylene and a copolymer of 90 mol% or more of propylene and other α-olefins of 10 mol% or less (hereinafter, these are collectively referred to as “polypropylene resin”) And an α-olefin resin containing 60% by weight or more and a compound represented by the above general formula (1) (hereinafter referred to as “compound (1)”) 100 to 1,000 ppm.
The α-olefin resin composition containing

[Α-olefin resin]
The α-olefin in the copolymer of 90 mol% or more of propylene and 10 mol% or less of the other α-olefin is selected from the group consisting of ethylene and an α-olefin having 4 to 10 carbon atoms. It is preferable to use the above, and specific examples thereof include, for example, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-methyl- 1-pentene etc. can be mentioned, 1 or more types selected from these can be used. The α-olefin used here is most preferably ethylene.
The copolymer can be preferably used regardless of whether it is a random copolymer or a block copolymer.
As melting | fusing point of the polypropylene resin in this invention, it is preferable that it is 125 degreeC or more, and it is more preferable that it is 125-165 degreeC.
The melt flow rate (MFR) measured at 230 ° C. in accordance with JIS K 7210 for the polypropylene resin in the present invention is preferably 1 to 30 g / 10 minutes, and preferably 3 to 10 g / 10 minutes. More preferably, it is particularly preferably 4 to 8 g / 10 minutes.
As the polypropylene-based resin in the present invention, the obtained base film is excellent in mechanical properties and can exhibit more suitable heat-resistant dimensional stability, and the occurrence of fish eyes in the obtained base film is reduced. In view of the above, it is preferable that a propylene homopolymer is included, the propylene homopolymer is preferably included in an amount of 50% by weight or more, more preferably 70% by weight or more, based on the whole polypropylene resin, and 90% by weight. % Is more preferable, and it is most preferable to use only a propylene homopolymer.

The α-olefin resin in the base film contains 60% by weight or more of the polypropylene resin as described above. As the α-olefin resin, only the polypropylene resin as described above may be used, or another resin may be used in combination with the polypropylene resin. Examples of other resins that can be used here include polyethylene resins. Examples of the polyethylene resin in this case include high-density polyethylene resin (HDPE), low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), and the like, and one kind selected from these The above can be used.
The proportion of the polypropylene resin used in the α-olefin resin is 60% by weight or more as described above, but 80% by weight from the viewpoint of mechanical properties, heat-resistant dimensional stability and low fisheye of the obtained base film. It is preferable to set it as the above, and it is more preferable to set it as 85 weight% or more. As the α-olefin resin in the present invention, it is most preferable to use only the polypropylene resin as described above.

[Compound (1)]
The compound (1) in the present invention is a compound represented by the general formula (1). This compound (1) is a component that functions as a nucleating agent when the polypropylene resin is crystallized when a base film is produced from the α-olefin composition. Therefore, from the viewpoint of high nucleation function, the group R ² in the general formula (1) is preferably a hydrogen atom or a methyl group.
Specific examples of such compound (1) include 1,2,3-propanetricarboxylic acid tricyclohexylamide, 1,2,3-propanetricarboxylic acid tri (2-methylcyclohexylamide), 1,2,3- Propanetricarboxylic acid tri (3-methylcyclohexylamide), 1,2,3-propanetricarboxylic acid tri (4-methylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetracyclohexylamide, 1,2, 3,4-butanetetracarboxylic acid tetra (2-methylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid tetra (3-methylcyclohexylamide), 1,2,3,4-butanetetracarboxylic acid Tetra (4-methylcyclohexylamide) and the like. It is preferred to use at least one member.
As the compound (1), a compound in which the group R ¹ in the general formula (1) is a propane-1,2,3-triyl group is preferable, and from the viewpoint of availability of the compound, 1,2,3-propane is preferred. Most preferred is tricarboxylic acid tri (2-methylcyclohexylamide). The 1,2,3-propanetricarboxylic acid tri (2-methylcyclohexylamide) is commercially available from Shin Nippon Rika Co., Ltd. under the trade name “Rikaclear PC-1.”

  The use ratio of the compound (1) in the α-olefin resin composition is 100 to 1,000 ppm as a weight ratio with respect to the α-olefin resin composition. It is very important from the viewpoint of balance. The ratio of the compound (1) used is preferably 250 to 750 ppm as a weight ratio with respect to the α-olefin resin composition. When the compound (1) is less than 100 ppm, the nucleating function cannot be sufficiently exhibited, and the heat-resistant dimensional stability of the base film is insufficient. On the other hand, when the compound (1) exceeds 1,000 ppm, in addition to impairing the economy, the crystallization speed of the base film obtained by excessive expression of the nucleation function becomes faster than necessary. As a result, in the production of the base film, the molten resin discharged from the die is crystallized (solidified) before coming into contact with the cooling roll, which may make it difficult to control the film thickness.

[Other ingredients]
The α-olefin resin composition in the present invention contains the α-olefin resin and the compound (1) as described above, but may contain other components in addition to these unless the effects of the present invention are impaired. .
Examples of other components that can be used here include a colorant. The colorant is added to the α-olefin composition for the following reasons.
When the protective film is used for the purpose of protecting the surface of the optical component, the protective film may be used on both surfaces as well as on one surface of the optical component. In that case, in order to easily distinguish the front and back of the optical component, it is widely practiced to use a protective film attached to one side as a colored film or a protective film attached to the front and back as colored films of different colors. Yes.
As a method of coloring the protective film, for example, a method of coloring by printing on the film surface, a method of blending a colorant into the resin constituting the film, and the like are known. Of these, when printing is performed, printing is performed in a separate process from film formation, which is inferior in economic efficiency and difficult to print uniformly and thinly on the surface. This may cause problems in the optical inspection of optical components due to this printing unevenness, and the surface printing ink may elute in the organic solvent used in the subsequent adhesive layering process. Such a problem arises.

As a method for solving the problem in the case of the above printing, when producing a biaxially stretched polypropylene film, a colored ink is applied to the film after being stretched in the longitudinal direction, dried, and then stretched in the transverse direction. A method for obtaining a colored film free from printing unevenness by a process has been proposed (Patent Document 3). However, the problem that the printing ink on the surface elutes into the organic solvent is still not solved, and the stretched film has a polarization property, so that it is not suitable as a protective film for optical parts that involve optical inspection.
Therefore, as a method of coloring the protective film, it is preferable to use a method of blending a colorant in the resin constituting the base film. As a result, the problem of ink elution into the organic solvent in the pressure-sensitive adhesive layer laminating step is solved, and the obtained protective film has no uneven coloring, so that it can be suitably used for optical inspection of optical components. .

As the colorant, a pigment is preferably used, and an organic pigment and an inorganic content generally used as a pigment for a resin can be suitably used.
Examples of the organic pigment include azo pigments, phthalocyanine pigments, anine pigments, quinacridone pigments;
Examples of the inorganic pigment include titanium oxide, bengara, ultramarine blue, carbon black, cobalt blue, and the like, and one or more selected from these can be used. Of these, the use of organic pigments is preferable because defects such as fish eyes caused by secondary aggregates of the pigments themselves are small and dispersibility in α-olefin resin is good.
The proportion of the colorant used in the α-olefin resin composition should be appropriately set depending on the thickness of the base film and the like, but is 0.01 parts by weight with respect to 100 parts by weight of the α-olefin resin. It is preferably ˜5 parts by weight. If the use ratio of the colorant is less than 0.01 parts by weight, the hue may not be clear and the presence or absence of coloring may not be obvious. On the other hand, when the ratio of the colorant used exceeds 5 parts by weight, not only the transparency (translucency) of the protective film to be obtained is lowered, but also defects such as fish eyes caused by secondary aggregates of the colorant itself. May occur and is not practical. In addition, the cost of the colorant is large and not economical.

In addition, although this colorant may be contained over the whole thickness direction of a base film, from a viewpoint of avoiding the adhesion of the colorant to the inside of a dice and the concern that a pigment elutes, It is preferable to make a multilayer film composed of one or more layers composed of an α-olefin resin composition not containing a colorant and one or more layers composed of an α-olefin resin composition containing a colorant,
The base film is composed of two outermost layers made of an α-olefin resin composition not containing a colorant, and one or more intermediate layers made of an α-olefin resin composition containing a colorant sandwiched therebetween. It is preferable to use a multilayer film having In the case of the latter, you may have further one or more of the intermediate | middle layers which consist of an alpha olefin resin composition which does not contain a coloring agent.
Most preferably, it consists of two outermost layers composed of an α-olefin resin composition containing no colorant and one intermediate layer composed of an α-olefin resin composition containing a colorant sandwiched between them. It is to make it a three-layer film.
When making the base film in this invention into a multilayer film, it is preferable that each of each layer contains the compound (1), and content of the compound (1) in each of each layer is said preferable range. More preferred.

[Thickness of base film]
Although the thickness of the base film in the protective film of the present invention can be appropriately set according to the area, shape, etc. of the adherend, it is preferably 10 to 100 μm, more preferably 20 to 80 μm. Especially preferably, it is 40-60 micrometers. Here, if the thickness of the base film is too thin, wrinkles due to “heat loss” may enter the film due to heating in the step of laminating the pressure-sensitive adhesive on the base film, making it impossible to use as a product. On the other hand, if the thickness of the base film is too thick, it may be insufficient in flexibility and may cause poor appearance such as wrinkles and bumps during the production of the wound body, and may be attached to an adherend having a surface with irregularities. In some cases, the surface shape of the adherend cannot be followed, and problems such as wrinkles and entrainment of bubbles may occur.
The base film in the present invention may be a single layer film or a multilayer film. When making a base film into a multilayer film, the film which consists of a multilayer which has the same composition may be sufficient, and the film which consists of a multilayer which has a different composition may be sufficient.
When making the base film in this invention into a multilayer film, it is preferable that the total thickness which totaled the thickness of each layer exists in the range of said recommendation thickness.
When the protective film of the present invention is a colored film, as described above, two outermost layers made of an α-olefin resin composition not containing a colorant and an α-olefin containing a colorant sandwiched between them. Although it is most preferable to set it as the 3 layer film which consists of 1 layer of the intermediate | middle layer which consists of a resin composition, Preferably it is as follows as thickness of each layer in this case.
The thickness of each outermost layer on the side where the adhesive is laminated and the side where the adhesive is not laminated is preferably 3 to 30 μm, more preferably 5 to 25 μm;
The thickness of the intermediate layer is preferably 3 to 60 μm, more preferably 5 to 50 μm; and the total thickness obtained by adding the thicknesses of the respective layers is preferably in the range described above as the thickness of the base film.

[Manufacture of base film]
The base film in the present invention can be produced by molding an α-olefin resin composition having the above composition without stretching.
Here, the α-olefin resin composition can be prepared by a known method. For example, the polypropylene resin constituting the α-olefin resin and optionally other resin pellets and the compound (1) and optionally the colorant are respectively charged into a suitable kneader at a predetermined ratio, preferably 200 to 300 It can use for manufacture of the base film in this invention, after knead | mixing at 0.1 degreeC preferably for 0.1 to 2 minutes. When an extruder is used to prepare the α-olefin resin composition, the die temperature is preferably the same as the resin temperature.
At this time, the compound (1) and the optionally used colorant may be used for preparing the composition as they are, but from the viewpoint of uniform dispersion in the composition, the compound (1) or It is preferable to prepare a master batch containing the colorant at a higher concentration than the desired concentration in the composition, and to use the pellets of the master batch for the preparation of the α-olefin resin composition. As the base resin for the masterbatch, it is preferable to use a polypropylene resin constituting the α-olefin resin.
The concentration of the compound (1) and the colorant in the master batch is preferably 0.1 to 10% by weight, more preferably 1 to 5% by weight per compound (1), and 0.1 to 0.1% per colorant. It is 10% by weight, more preferably 1 to 5% by weight.

Forming the α-olefin resin composition as described above without stretching means that the melted α-olefin resin composition is not substantially stretched between the cooling roll (chill roll) and the winding roll after solidification. It will be apparent to those skilled in the art that the molten composition is not prohibited from being stretched due to the necessity of the process when it is formed into a film. The term “non-stretched” as used herein is a concept that includes a case where the film is not stretched at all, and a case where the film is not substantially stretched. The stretch ratio is 1.2 times or more, preferably 1.05 times or more. A film formed without undergoing a uniaxial or more stretching process satisfies the requirement of “no stretching” in the present invention.
This requirement is very important because a protective film manufactured using a non-stretched base film in this sense is extremely excellent in dimensional stability after becoming a protective film. A film formed through a uniaxial stretching process with a stretching ratio of 1.2 times or more has a certain advantage in dimensional stability against heat and tension in the process of laminating an adhesive on the film. However, since relaxation of stretching is observed after that, the dimensional stability after becoming a protective film is very inferior, which is not preferable. Moreover, since the obtained base film has a polarization characteristic, it is not preferable for use as a protective film for optical components that involve optical inspection.
For non-stretch molding, for example, an inflation method, a casting method, or the like can be employed. In particular, an unstretched film formed by a casting method is preferable in that it has excellent dimensional stability both in the step of laminating an adhesive and after becoming a protective film.
When making the base film in this invention into a multilayer film, well-known methods, such as the coextrusion method represented by the multi-manifold method and the feed block method, an in-line laminating method, can be employ | adopted, for example. Each layer may be laminated via an adhesive layer by dry lamination or the like.

[Base film]
The base film in the present invention produced as described above is a test piece obtained by cutting the base film into 300 mm (MD direction) × 100 mm (TD direction) at 80 ° C. under a load of 1,000 g. The first dimensional change rate after standing for a minute is 2.5% or less in the MD direction and 1.2% or less in the TD direction with respect to the initial value, and the first dimensional change rate is The second dimensional change rate after the test piece after measurement was further allowed to stand at 100 ° C. for 15 minutes under no load was 1.2 in the MD direction with respect to the test piece after the first dimensional change rate measurement. % Or less and 0.8% or less in the TD direction. By having such a heat-resistant dimensional change rate, the distortion of the base film in the step of laminating the pressure-sensitive adhesive layer on the base film is reduced, and after the obtained protective film is attached to the adherend Since distortion in heating is also reduced, the protective film does not float or peel off from the adherend.
The first dimensional change rate is preferably 2.0% or less in the MD direction and 1.0% or less in the TD direction;
The second dimensional change rate is preferably 1.0% or less in the MD direction and 0.5% or less in the TD direction.
To apply a load to the test piece when measuring the first rate of dimensional change, mount the eyeball clip on the upper and lower sides of the test piece in the MD direction, and hang a weight on the lower eyepiece clip. It can be done by a method of making it suspended by the upper eyeball clip.

The base film in the present invention has a tensile elastic modulus of 700 MPa or more in each of the MD direction and the TD direction from the viewpoint of dimensional stability against heat and tension applied to the base film in the step of laminating the pressure-sensitive adhesive. It is preferable that it is 900 MPa or more.
The base film in the present invention has very little fish eye. In the base film used for the protective film, the size and number of fish eyes are very important. That is, if fish eyes with a large size are present in the base film, they become an optical disturbance factor when they are attached to an adherend (for example, an optical component) and optical inspection is performed. Even if it exists, it may be judged as inferior goods. Even if there are many fish eyes of small size, it becomes an optical disturbance factor as well.
In the base film of the present invention, the number of fish eyes having a major axis of less than 1.0 mm can be 5 / m ² or less, and further 3 / m ² or less. The number of fish eyes having a major axis of 1.0 mm or more can be 1 / m ^2, and can further be 0 / m ² . Therefore, even when the base film of the present invention is used for a protective film of an optical component, there are very few optical disturbance factors due to fish eyes, and an appropriate result can be obtained in optical inspection of the optical component. it can.

<Manufacture of protective film (lamination of adhesive layer)>
The protective film of the present invention can be produced by laminating an adhesive layer on the base film as described above.
At this time, in order to further increase the adhesion between the base film and the pressure-sensitive adhesive layer laminated thereon, the surface of the base film on the side where the pressure-sensitive adhesive is laminated is subjected to surface treatment inline or offline. It is preferable to laminate an adhesive. Examples of such surface treatment include corona discharge treatment and flame (flame) treatment. It is preferable to carry out the step of laminating the pressure-sensitive adhesive layer after setting the wetting index of the substrate film surface on the side where the pressure-sensitive adhesive is laminated to 38 to 46 mN / m by these appropriate treatments.
There is no restriction | limiting in particular about the kind of adhesive laminated | stacked on a base film, For example, well-known adhesive agents or adhesives, such as an acryl type, a rubber type, a urethane type, and a silicone type, can be used preferably. The method for laminating the pressure-sensitive adhesive layer is not particularly limited, and a known method, for example, coating based on a transfer method of a commonly used coating head (for example, gravure, gravure rib, offset, etc.), bar, A generally used method using a coating apparatus such as coating based on a scraping method such as a comma can be employed.
The thickness of the adhesive layer can be appropriately set according to the use of the protective film, and can be 3 to 100 μm, for example, and 5 to 50 μm from the viewpoint of the balance between tackiness and economy. Is preferred.
After laminating an adhesive on one side of the base film to form a laminated film, the laminated film is heated at 80 to 100 ° C. to cure the adhesive and adhere the adhesive layer to the base film. It is preferable. This heating can be performed using, for example, a suitable drying furnace. The heating time is preferably 0.1 to 5 minutes, and more preferably 0.5 to 3 minutes.

<Protective film>
The protective film of the present invention produced as described above is very excellent in heat-resistant dimensional stability.
Since the protective film of the present invention is not substantially stretched in the production process of the base film, there is no distortion due to relaxation of the stretch, and therefore, due to the reason for manufacturing the adherend after application to the adherend. Even when heated, peeling or floating does not occur, and this is particularly suitable for application to optical components.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
Example 1
<Manufacture of base film>
Homo-polypropylene-A (H-PP-A: manufactured by Sumitomo Chemical Co., Ltd., product number: FLX80E4, melting point = 163 ° C., MFR = 7 g / 10 min; at 230 ° C.) and compound (1) as a nucleating agent A film was prepared by the following method using Masterbatch-A (a polypropylene containing 2.5% by weight of “Rikaclear PC-1” manufactured by Shin Nippon Rika Co., Ltd.).
T-die type film formation with 3 types and 3 layers consisting of a single screw extruder of 75 mm for the intermediate layer and two single screw extruders of 50 mm for both outer layers. A device was used. A resin composition (nuclear agent content: 500 ppm) in which 98 parts by weight of homo-polypropylene-A and 2 parts by weight of masterbatch A of compound (1) are mixed in an intermediate layer extruder is used as an extruder for both outer layers. A resin composition (nuclear agent content: 500 ppm) in which 98 parts by weight of homo-polypropylene-A and 2 parts by weight of masterbatch-A were mixed was supplied, respectively, resin temperature 250 ° C., residence time 1 minute, T-die temperature 240 ° C. A three-layer unstretched polypropylene film having a total thickness of 40 μm was obtained by extrusion from a T-die under the conditions of Next, a corona discharge treatment was applied so that the wetting index of the surface of the film on which the pressure-sensitive adhesive was laminated was 42 mN / m, and aging was performed at 40 ° C. for 24 hours to obtain a base film.

<Evaluation of base film>
[Evaluation of basic characteristics of film]
The following (1) to (4) were evaluated for the base film obtained by the above method. The evaluation results are shown in Table 2.
(1) Haze Haze was measured according to JIS K 7105 using a haze meter (model number: HGM-2DP) manufactured by Suga Test Instruments Co., Ltd. as an index of turbidity of the base film.
(2) Tensile elastic modulus Made by Shimadzu Corp., Autograph (model number: AG-500D), in accordance with JIS K 7127, using a JIS-5 test piece at a tensile speed of 50 mm / min. The tensile modulus was measured for each of the MD direction and the TD direction.
(3) Fish eye The base film was cut into a size of 500 mm × 500 mm (0.25 m ² ) and used as a test piece. The fish eyes present in the test piece were visually observed, and the major axis of each discovered fish eye was measured using a loupe with a scale having a minimum unit of 0.1 mm. The same measurement was performed on 8 test pieces (0.25 m ² × 8 = 2 m ² ), and the number of found fish eyes was converted into the number per 1 m ² and evaluated.

(4) Degree of crystallinity As an index of crystallinity of the substrate film, an X-ray diffraction measurement (model number: JDX-3500) manufactured by JEOL Ltd. was used, and X-ray diffraction measurement was performed under the following conditions to cause crystallization. The degree was calculated.
Target: Copper (Cu-Kα line)
Tube voltage-tube current: 40 kV-400 mA
X-ray incidence method: vertical beam transmission method Monochromatization: graphite monochromator Divergence slit: 0.2 mm
Receiving slit: 0.4mm
Detector: Scintillation counter Measurement angle range: 9.0 ° to 31.0 °
Step angle: 0.04 °
Counting time: 4.0 seconds Sample rotation speed: 120 rotations / minute The crystallinity is obtained by performing peak separation of the diffraction intensity curve, and the diffraction angle 2θ is 14.2 °, 17.1 °, 18.6 °, The sum of the crystalline peak areas observed near 21.4 °, 21.9 °, 25.7 °, and 28.6 ° is the S _c , broad amorphous shape observed near 16.3 °. when the peak area was _{S a,} the following equation (i)

By calculation.
[Evaluation of heat-resistant dimensional change rate]
The following (5) and (6) were evaluated for the base film obtained above. The evaluation results are shown in Table 2.
(5) First dimensional change rate After laminating the pressure-sensitive adhesive on the base film, the following measurements were performed for the purpose of examining the distortion of the base film in a state where temperature and tension were applied in a drying furnace.
The base film obtained above was cut into 300 mm (MD direction) × 100 mm (TD direction), and a test line was drawn at the center with a marked line of 200 mm in the MD direction and 100 mm in the TD direction. With the MD direction of this test piece as the vertical direction, eyeball clips are attached to the upper and lower parts, respectively, and a weight with a load of 1,000 g is hung on the lower eyeball clip, and suspended in an oven at 80 ° C. by the upper eyeball clip. And left to heat for 10 minutes. After the heating, the test piece was taken out from the oven, and the suspended state with the load applied was maintained for 2 minutes and naturally cooled to room temperature. After cooling, the weight is removed, the length of each marked line is measured with a ruler, and the following formula (ii)

Thus, the first dimensional change rate was calculated.
(6) Second dimensional change rate For the purpose of examining the heat-resistant dimensional stability after being attached to the adherend as a protective film, the following measurements were performed.
The test piece after the first dimensional change rate measurement was left in a 100 ° C. oven for 15 minutes and reheated. After 15 minutes, the reheated test piece is taken out of the oven, the length of the marked line is measured with a ruler, and the following formula (iii)

Thus, the second dimensional change rate was calculated. In addition, “the length of the marked line before reheating” in the mathematical formula (iii) is synonymous with “the length of the marked line after heating” in the mathematical formula (ii).
[Evaluation of adhesion]
An acrylic pressure-sensitive adhesive (manufactured by Soken Chemical Co., Ltd., product name: SK Dyne 1310) is applied to the corona-treated surface of the base film obtained above, and heated at 80 ° C. for 1 minute, thereby having a thickness of 10 μm. An adhesive layer was laminated.
The following (7) was evaluated about the film which has this adhesive layer. The evaluation results are shown in Table 2.
(7) Adhesiveness with adherend After affixing a protective film on which an adhesive was laminated by the above method to a 100 mm × 100 mm acrylic plate, the protruding portion was cut to obtain a test piece. This test piece was left to stand in an oven at 100 ° C. for 15 minutes and heated. After 15 minutes, the test piece was taken out from the oven, the adhesion between the acrylic plate and the adhesive film was visually confirmed, and the adhesion was evaluated according to the following criteria.
Good: When no peeling or lifting of the adhesive film was observed.
Defect: When the adhesive film edge is peeled off, the film is lifted (that is, mixed with bubbles) other than the edge, and the appearance is poor.

Example 2
A resin composition (containing a nucleating agent) obtained by mixing 96 parts by weight of homo-polypropylene-A and 4 parts by weight of a master batch of compound (1) with a resin composition supplied to each extruder for the intermediate layer and both outer layers. A substrate film was obtained in the same manner as in Example 1 except that the amount was 1,000 ppm.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Example 3
The resin composition supplied to each of the extruders for the intermediate layer and for both outer layers was random-polypropylene-A (R-PP-A: manufactured by Prime Polymer Co., Ltd., product number: F327BV, melting point = 138 ° C., MFR = 7 g. / 10 minutes; at 230 ° C., a resin composition in which 98 parts by weight of ethylene content = 2 mol% and butene content 2 mol%) and 2 parts by weight of Masterbatch-A of Compound (1) (nuclear agent content: 500 ppm) The substrate film was obtained in the same manner as in Example 1 except that.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.

Example 4
The resin composition to be supplied to each of the extruders for the intermediate layer and the outer layer is block-polypropylene-A (B-PP-A: manufactured by Nippon Polypro Co., Ltd., product number: BC3HF, melting point = 162 ° C., MFR = 7 g. / 10 minutes; at 230 ° C., ethylene content = 9 mol%) 98 parts by weight and compound (1) Masterbatch-A 2 parts by weight were mixed into a resin composition (nucleating agent content: 500 ppm), The substrate film was obtained in the same manner as in Example 1.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Example 5
Resin composition prepared by mixing 75 parts by weight of homo-polypropylene-A, 23 parts by weight of block-polypropylene-A, and 2 parts by weight of master batch A of compound (1) with a resin composition supplied to the extruder for the intermediate layer (Nucleating agent: 500 ppm) and the resin composition supplied to the extruder for both outer layers is 63 parts by weight of homo-polypropylene-A, 23 parts by weight of block-polypropylene-A, low density polyethylene (LDPE: Ube Maruzen Polyethylene Co., Ltd.) ), Product number: F522N, density = 0.922 g / cm ³ , melting point = 108 ° C., MFR = 5 g / 10 min; at 190 ° C.) 12 parts by weight and 2 parts by weight of the master batch of compound (1) -A A base film was obtained in the same manner as in Example 1 except that the content (nuclear agent content: 500 ppm) was used.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.

Example 6
The same resin composition as in Example 1 is supplied to each of the three extruders of the film forming apparatus used in Example 1, and the resin temperature is 250 ° C., the residence time is 1 minute, and the T-die temperature is 240 ° C. Except that it was extruded from a T-die, cooled with a cooling roll at 30 ° C., and then stretched 1.1 times in the longitudinal direction using a preheating roll and a stretching roll at 130 ° C. in the next roll. It carried out like Example 1 and obtained the substrate film.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Example 7
The resin composition to be supplied to the extruder for the intermediate layer was composed of 93 parts by weight of homo-polypropylene-A, 2 parts by weight of master batch A of compound (1) and a master batch of colorant (phthalocyanine blue) (DIC Corporation). Polypropylene containing about 5% by weight of “PEONY HP BLUE L-83285M” manufactured by the same company.) Resin composition mixed with 5 parts by weight (nucleating agent content: 500 ppm, coloring agent content: 0.25% by weight) A base film was obtained in the same manner as in Example 1 except that.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
In addition, it was confirmed that the said base film does not have elution of printing ink to the organic solvent at the time of adhesion layer lamination.

Comparative Example 1
A base film was obtained in the same manner as in Example 1 except that 100 parts by weight of homo-polypropylene-A was supplied to each of the extruder for the intermediate layer and the outer layer.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Comparative Example 2
Example 1 except that 100 parts by weight of homo-polypropylene-A was supplied to each of the extruders for the intermediate layer and both outer layers, and the temperature of the cooling roll during the production of the base film was 60 ° C. The substrate film was obtained in the same manner.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Comparative Example 3
The resin composition supplied to each of the extruders for the intermediate layer and the outer layer was prepared by adding 99 parts by weight of homo-polypropylene-A and a master batch-B (manufactured by Adeka Co., Ltd.) containing a phosphate ester compound as a nucleating agent. M-801 "(polypropylene ester aluminum salt) containing 5% by weight.) Same as Example 1 except that 1 part by weight of the resin composition was mixed (nucleating agent content: 500 ppm). This was carried out to obtain a base film.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.

Comparative Example 4
Masterbatch-C (manufactured by Dainichi Seika Kogyo Co., Ltd.) containing 99.5 parts by weight of homo-polypropylene-A and a sorbitol compound as a nucleating agent for the resin composition to be supplied to each extruder for the intermediate layer and both outer layers "H200" (a sorbitol-based derivative) of 10% by weight.) Same as Example 1 except that 0.5 parts by weight of the resin composition was mixed (nucleating agent content: 500 ppm). This was carried out to obtain a base film.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Comparative Example 5
The resin composition to be supplied to each of the extruders for the intermediate layer and the outer layer is block-polypropylene-B (manufactured by Sun Allomer Co., product number: PC480A, melting point = 165 ° C., MFR = 2 g / 10 minutes; 230 ° C. , Ethylene content = 11 mol%) The same as Example 1 except that 98 parts by weight and 2 parts by weight of Masterbatch-A (1) were mixed (nuclear agent content: 500 ppm). Thus, a base film was obtained.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.

Comparative Example 6
A three-layer three-layer tenter system with two single-screw extruders with a screw diameter of 90 mm for the intermediate layer and two single-screw extruders with a screw diameter of 65 mm for both outer layers. Homo-polypropylene-B (manufactured by Prime Polymer Co., Ltd., product number: F300SP, melting point = 160 ° C., MFR = 3 g / 10 min; at 230 ° C.) was used for the intermediate layer extruder using an axially stretched film forming apparatus. Homo-polypropylene-B (manufactured by Prime Polymer Co., Ltd., product number: F300SP, melting point = 160 ° C., MFR = 3 g / 10 min; at 230 ° C.) was supplied to the extruder for both outer layers, resin temperature 250 ° C., die Extruded from a T-die at a temperature of 250 ° C., made a sheet of about 1.5 mm through a cooling roll at 30 ° C., continuously stretched about 5 times in the machine direction and about 10 times in the transverse direction, with a total thickness of 40 μm of To obtain a biaxially drawn polypropylene film. Next, a corona discharge treatment was applied so that the wetting index of the surface of the film on which the pressure-sensitive adhesive was laminated was 42 mN / m, and the film was aged at 40 ° C. for 48 hours to obtain a base film.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Comparative Example 7
The same as in Comparative Example 6 except that the resin supplied to the three extruders of the film forming apparatus used in Comparative Example 6 was random-polypropylene-A and the stretch ratio was about 4 times only in the longitudinal direction. And a substrate film was obtained.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.

Comparative Example 8
The resin composition to be supplied to the extruder for the intermediate layer and the outer layer is random-propylene-B (manufactured by Prime Polymer Co., Ltd., product number: T310E, melting point = 152 ° C., MFR = 1.5 g / 10 min; 230 ° C. Except that the resin composition (nuclear agent content: 500 ppm) in which 98 parts by weight of ethylene content = 21 mol%) and 2 parts by weight of Masterbatch-A of compound (1) was mixed was the same as in Example 1 above. This was carried out to obtain a base film.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.
Comparative Example 9
Resin composition (nucleating agent) in which 98 parts by weight of homo-polypropylene-B and 2 parts by weight of masterbatch A of compound (1) were mixed in each of the three extruders of the film forming apparatus used in Comparative Example 6 A base film was obtained in the same manner as in Comparative Example 6 except that the content was 500 ppm.
Various evaluations were performed in the same manner as in Example 1 using this base film. The evaluation results are shown in Table 2.

In addition, the abbreviation of the raw material in Table 1 has the following meaning, respectively.
<Polypropylene resin>
H-PP-A: Homo-polypropylene-A (manufactured by Sumitomo Chemical Co., Ltd., product number: FLX80E4, melting point = 163 ° C., MFR = 7 g / 10 min; at 230 ° C.)
H-PP-B: Homo-polypropylene-B (manufactured by Prime Polymer Co., Ltd., product number: F300SP, melting point = 160 ° C., MFR = 3 g / 10 min; at 230 ° C.)
R-PP-A: Random-polypropylene-A (manufactured by Prime Polymer Co., Ltd., product number: F327BV, melting point = 138 ° C., MFR = 7 g / 10 min; ethylene content = 2 mol%, butene content 2 mol at 230 ° C. %)
B-PP-A: Block-polypropylene-A (manufactured by Nippon Polypro Co., Ltd., product number: BC3HF, propylene-ethylene-block copolymer type, melting point = 162 ° C., MFR = 7 g / 10 min; ethylene at 230 ° C., ethylene (9 mol% content)
<Other resins>
R-PP-B: Random-propylene-B (manufactured by Prime Polymer Co., Ltd., product number: T310E, melting point = 152 ° C., MFR = 1.5 g / 10 min; at 230 ° C., ethylene content = 21 mol%)
B-PP-B: Block-polypropylene-B (manufactured by Sun Allomer Co., Ltd., product number: PC480A, melting point = 165 ° C., MFR = 2 g / 10 min; at 230 ° C., ethylene content = 11 mol%)
LDPE: Low density polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., product number: F522N, density = 0.922 g / cm ³ , melting point = 110 ° C., MFR = 5.0 g / 10 min; at 190 ° C.)

<Nucleating agent master batch>
Nucleating agent MB-A: Master batch of compound (1) -A (a polypropylene containing 2.5% by weight of “Rikaclear PC-1” manufactured by Shin Nippon Rika Co., Ltd.)
Nucleating agent MB-B: Master batch of phosphate ester compound-B (polypropylene containing 5% by weight of “M-801” (phosphate ester aluminum salt) manufactured by Adeka Co., Ltd.)
Nucleating agent MB-C: Master batch of sorbitol derivative-C (polypropylene containing 10% by weight of “H200” (sorbitol derivative) manufactured by Dainichi Seika Kogyo Co., Ltd.)
<Masterbatch containing colorant>
Colorant MB: Phthalocyanine blue masterbatch (polypropylene containing about 5% by weight of “PEONY HP BLUE L-83285M” manufactured by DIC Corporation)

Claims (6)

An α-olefin resin containing at least 60% by weight of at least one selected from the group consisting of a homopolymer of propylene and a copolymer of 90 mol% or more of propylene and 10 mol% or less of another α-olefin, and The following general formula (1)

(In the formula (1), R ¹ is a propane-1,2,3-triyl group or a butane-1,2,3,4-tetrayl group,
R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms,
K is 3 when R ¹ is a propane-1,2,3-triyl group;
When R ¹ is a butane-1,2,3,4-tetrayl group, k is 4, and a plurality of R ² may be the same or different. )
100 to 1,000 ppm of a compound represented by
A protective film formed by laminating an adhesive layer on one side of a base film made of an α-olefin resin composition containing
The first dimensional change rate after the test piece obtained by cutting the base film to 300 mm (MD direction) × 100 mm (TD direction) at 80 ° C. for 10 minutes under a load of 1,000 g is the initial With respect to the value, it is 2.5% or less in the MD direction and 1.2% or less in the TD direction, and the test piece after measuring the first dimensional change rate is further subjected to 15 minutes at 100 ° C. under no load. The second dimensional change rate after standing is 1.2% or less in the MD direction and 0.8% or less in the TD direction with respect to the test piece after the first dimensional change rate measurement. The protective film as described above.   The protective film according to claim 1, wherein the described film is produced by molding an α-olefin resin composition without stretching. The protective film according to claim 1 or 2, wherein the number of fish eyes having a major axis of less than 1.0 mm is 5 / m ² or less, and the number of fish eyes having a major axis of 1.0 mm or more is 0 / m ² .   The base film is a multilayer film comprising one or more layers made of an α-olefin resin composition not containing a colorant and one or more layers made of an α-olefin resin composition containing a colorant. The protective film as described in any one of Claims 1-3.   The base film is composed of two outermost layers composed of an α-olefin resin composition not containing a colorant and one or more intermediate layers composed of an α-olefin resin composition containing a colorant sandwiched between them. The protective film according to claim 4, wherein the protective film is a multilayer film. An α-olefin resin containing at least 60% by weight of at least one selected from the group consisting of a homopolymer of propylene and a copolymer of 90 mol% or more of propylene and 10 mol% or less of another α-olefin, and 100 to 1,000 ppm of the compound represented by the general formula (1)
A non-stretched α-olefin resin composition containing a base film,
2. The protective film according to claim 1, wherein the protective film according to claim 1 is manufactured by laminating an adhesive or the like on one side of the base film to obtain a laminated film and heating the laminated film at 80 to 100 ° C. 3. Way for.