KR20120112846A - Surface protective film - Google Patents

Abstract

This invention makes it a subject to provide the surface protection film which has high adhesive force and the outstanding rollability. This invention is a surface protection film which consists of at least 2 layer of a surface layer (A) and adhesion layer (X), Comprising: A surface layer (A) consists of a propylene polymer, and the surface roughness (Ra) of a surface layer is 0.2-2.0 micrometers. It is a surface protection film in the range of. Moreover, it is the said surface protection film whose adhesive force with respect to acryl is 1 N / 50mm, and the adhesion layer (X) is formed with the olefin type elastomer and / or the styrene type elastomer, It is the said surface protection film characterized by the above-mentioned.

Description

Surface protection film {SURFACE PROTECTIVE FILM}

TECHNICAL FIELD This invention relates to the surface protection film used for optical goods, building materials, automobile parts, etc. In detail, it is excellent in adhesive property, transparency, and heat resistance, there is little contamination by a to-be-adhered body, etc. Moreover, the easiness of feeding when feeding out from the state in which the film was wound up in roll shape (henceforth "feedability") It is related with this excellent surface protection film.

The surface protection film mainly adheres to adherends such as resin products, metal products, and glass products for building materials and optical applications, and serves to prevent scratches and foreign matters from being transported, stored or processed. . These surface protection films generally consist of a surface layer without adhesiveness, and the adhesion layer for sticking with the said to-be-adhered body. The surface layer is usually formed of a polyolefin such as polyethylene or polypropylene, polyester such as polyethylene terephthalate, or vinyl polymer such as polyvinyl chloride.

In recent years, development of the member used for a liquid crystal display, a plasma display (PDP), a rear projection screen, etc., what is called an optical product is progressing. With respect to the surface protection film for protecting these optical products, not only a wound | wound and a foreign material mixing but also characteristics, such as transparency to the extent that product inspection can be performed in the state which attached the surface protection film, are desired.

Moreover, when a surface protection film is used for building materials and automotive parts uses, it may thermoform in the state which attached the surface protection film, and high heat resistance to such an extent that it can be used as a surface protection film is calculated | required even in high temperature state.

In addition, in the surface protection film which has comparatively high adhesive force, since it does not have sufficient feeding property, it is made into the roll state which bonded and rolled up the release film with respect to the adhesion layer, and peeled off and used this release film at the time of attachment to a to-be-adhered body. have. If such a means is employed, a large amount of release film is generated as waste, and thus a surface protection film having sufficient feeding ability is required even without a release film.

Patent Document 1 discloses a surface protective film mainly composed of a polyethylene component. However, as the protective film of this publication, although it is applicable to some use members, adhesiveness was low and transparency was inadequate, and the use of the to-be-adhered body had a limit.

In patent document 2, the protective film which consists of a back layer and an adhesion layer obtained using a specific resin composition is disclosed. However, as the protective film of this publication, prevention of fish eye generation is not enough, and especially when used as a protective film, such as an optical member, there exists a possibility that it may adversely affect a to-be-adhered body, and improvement is calculated | required.

Japanese Patent Publication No. 2006-116769 Japanese Patent Publication No. 2009-28938

The subject of this invention is the characteristic calculated | required as a surface protection film for protecting these at the time of storage, transportation, processing, and inspection of an optical product, a building material product, or an automotive component, especially adhesive property, transparency, heat resistance, and extractability An excellent surface protection film is provided.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in view of the said subject, it discovered that the said subject can be solved by the surface protection film which has a surface layer which consists of a specific resin composition, and came to complete this invention.

That is, this invention is a surface protection film which consists of at least 2 layer of a surface layer (A) and adhesion layer (X), Comprising: A surface layer (A) consists of a propylene polymer, and the surface roughness (Ra) of a surface layer is 0.2? It is related with the surface protection film in the range of 2.0 micrometers.

Moreover, the preferable aspect of this invention is the said surface protection film whose adhesive force with respect to acryl is 1 N / 50mm or more, Moreover, the said adhesive layer (X) is formed with an olefin elastomer and / or styrene elastomer, The said surface protection characterized by the above-mentioned. It is a film.

The surface protection film of this invention is excellent in adhesiveness, transparency, the extractability from the state wound up in roll shape, and heat resistance, and is suitable as a surface protection film for optical use, building material use, and automotive parts use.

Next, the present invention will be described in detail.

The surface protection film of this invention consists of at least 2 layer of a surface layer (A) and adhesion layer (X).

The surface layer (A) consists of a propylene polymer.

As a propylene polymer, a random or block copolymer with propylene homopolymer, propylene, and ethylene and / or a C4-20 alpha-olefin is mentioned, for example.

1-butene, 4-methylpentene-1,1-hexene, 1-octene etc. are mentioned as a C4-C20 alpha olefin used for the said random or block copolymer. As such copolymerization, a propylene ethylene copolymer, a propylene 1-butene copolymer, a propylene ethylene 1-butene copolymer, etc. are mentioned.

As for a propylene polymer, melting | fusing point from a viewpoint of heat resistance improvement becomes like this. Preferably it is 50-170 degreeC, More preferably, it is 70-170 degreeC, More preferably, it is 100-165 degreeC, Especially, 130-165 degreeC is the most preferable. Here, melting | fusing point is the value measured by the differential scanning calorimeter (DSC) at the temperature rising and temperature-fall rate 10 degree-C / min.

Further, the propylene polymer has a melt flow rate (hereinafter abbreviated as MFR) measured at 230 ° C, preferably 0.01 to 500 g / 10 min, more preferably 0.1 to 100 g / 10 min, still more preferably 0.3 to 50 g. It is in the range of / 10 minutes.

The propylene polymer is a homopolymer of propylene or propylene in the presence of a metal titaniumene catalyst, a geometrical catalyst, and the like as well as a solid titanium catalyst mainly composed of a solid titanium compound and an alkyl aluminum compound. It is obtained by copolymerizing ethylene and / or α-olefin having 4 to 20 carbon atoms together.

In the surface protection film of this invention, the surface roughness (Ra) of the surface layer (A) which consists of the said propylene polymer from the viewpoint of transparency and drawability exists in the range of 0.2-2.0 micrometers. Especially, as for surface roughness Ra, 0.3 micrometer or more is preferable, and also 0.4 micrometer or more is preferable. Moreover, 1.5 micrometers or less are preferable and, as for surface roughness Ra, 1.2 micrometers or less are more preferable. If the surface roughness is less than 0.2 µm, the surface layer will be difficult to peel off from the pressure-sensitive adhesive layer, and the feeding ability is lowered. On the other hand, when the said surface roughness exceeds 2.0 micrometers, sufficient transparency cannot be acquired by the diffuse reflection of the light beam on a surface.

Although there is no restriction | limiting in particular as a method of forming the surface roughness of the said surface layer, The method of transferring a embossing roll to a surface layer and forming surface roughness, or the method of controlling surface roughness by changing the molecular weight and composition of the said propylene polymer is used. do. From the viewpoint of productivity, a method of controlling the molecular weight and composition of the propylene polymer is preferably employed. As an example of the propylene polymer for implementing preferable surface roughness, the method of using the block copolymer of propylene and ethylene (henceforth a "propylene ethylene block copolymer") is mentioned. MFR (230 degreeC) of a propylene ethylene block copolymer becomes like this. Preferably it is 3-20g / 10min, More preferably, it is the range of 4-15g / 10min. It is preferable that the intrinsic viscosity ([η]) of the rubber component in a propylene ethylene copolymer is 2.0 dl / g or more.

Among the propylene polymers used as the surface layer (A), antistatic agents, mold release agents, antioxidants, weathering agents, crystal nucleating agents, etc., for the purpose of imparting antistatic properties and weather resistance to the surface protective film of the present invention, improving transparency and improving appearance, etc. It is also possible to add various additives and resin modifiers such as other crystalline polyolefins such as polyethylene and polybutene, polyesters, polyamides, and elastomers.

In the case where an additive or a modifier is added to the propylene polymer as necessary, the additive may be processed into a film after adding an additive or the like, and then kneading with a single screw or a twin screw extruder, a feeder luder or the like, but the T- having a extruder It can also feed directly into a die molding machine, and can also set it as the surface layer (A) of the surface protection film of this invention.

As the adhesion layer (X) of the surface protection film of this invention, if it is a well-known adhesive used as the adhesion layer of a surface protection film, it can be used, but it can be used for the damage of the to-be-adhered body by the occurrence of a fish eye, and the to-be-adhered body of an adhesive. From the viewpoint of the transition, that is, adhesive residue, it is preferable that they are an olefin elastomer and / or a styrene elastomer. More preferably, it is a composition which consists of an olefin elastomer or an olefin elastomer and a styrene elastomer.

As an olefin elastomer, the melting point by the DSC measurement (measured at the temperature rising and falling rate of 10 degree-C / min) of amorphous elastomer which is not observed in the range of 0-200 degreeC, or the melting point peak observed in the range of 0-200 degreeC Microcrystalline elastomers in which peaks of melting heat of 10 J / g or less are observed are more preferable, and more preferably, amorphous elastomers or microcrystalline elastomers of melting heat of melting point peaks of 7 J / g or less.

As said olefin elastomer, there exists a C2-C20 alpha-olefin polymer or copolymer, or the copolymer of ethylene and unsaturated carboxylic acid or unsaturated carboxylic ester. Specifically, an ethylene propylene copolymer, an ethylene 1-butene copolymer, an ethylene 1-hexene copolymer, an ethylene 4-methylpentene-1 copolymer, an ethylene 1-octene copolymer, a propylene homopolymer, and propylene Ethylene copolymer, propylene ethylene 1-butene copolymer, 1-butene homopolymer, 1-butene ethylene copolymer, 1-butene propylene copolymer, 4-methylpentene-1 homopolymer, 4-methylpentene -1? Propylene copolymer, 4-methylpentene-1? 1-butene copolymer, 4-methylpentene-1? Propylene? 1-butene copolymer, propylene? 1-butene copolymer, ethylene? Vinyl acetate copolymer, Ethylene methacrylate copolymer, an ethylene methyl methacrylate copolymer, etc. are mentioned. From the point of time-lapse stability of adhesive force, Preferably, they are a propylene homopolymer, a propylene ethylene copolymer, a propylene 1-butene copolymer, and a propylene ethylene 1-butene copolymer.

As the styrene-based elastomer, a known styrene-based elastomer having a polystyrene phase as a hard segment can be used. Specifically, styrene butadiene copolymer (SBR), styrene isoprene styrene copolymer (SIS), styrene butadiene styrene copolymer (SBS), and hydrides thereof (SEBS, SEPS, etc.), styrene isobutylene styrene triblock copolymer (SIBS), and styrene isobutylene diblock copolymer (SIB). From the standpoint of adhesiveness and extractability with the adherend, styrene isobutylene styrene triblock copolymer (SIBS) and styrene isobutylene diblock copolymer (SIB) are preferable.

The adhesive layer (X) in the surface protection film of this invention can be formed by using the said olefin elastomer and / or styrene-type elastomer, respectively, or the blend of components of a different composition. In addition, in the present invention, for the purpose of controlling the adhesive force and in the range that does not impair the effects of the present invention, resin modifiers such as polyolefins such as polyethylene and polypropylene, acid-modified polyolefins, polyesters, polyamides, Various additives, such as an antistatic agent, a crystal nucleating agent, and antioxidant, may be included.

In the case where the olefin elastomer and / or styrene elastomer is used to form the adhesive layer (X) of the surface protective film of the present invention, the olefin elastomer comprises 0 to 80% by weight of the olefin elastomer and 20 to 100% by weight of the styrene elastomer. More preferably 0 to 75% by weight of olefin elastomer and 25 to 100% by weight of styrene elastomer, more preferably 5 to 75% by weight of olefin elastomer and 25 to 95% by weight of styrene elastomer ( Although other components may be contained in an adhesion layer as needed, in order to demonstrate the ratio between an olefin type elastomer and a styrene type elastomer, the sum total with respect to these is shown as 100 weight%).

The adhesion layer (X) in the surface protection film of this invention can be formed by using the said olefin elastomer and / or styrene-type elastomer individually or individually by using the component of a different composition. In addition, in the adhesion layer (X), resin modifiers, such as polyolefins, such as polyethylene and a polypropylene, acid-modified polyolefin, polyester, and polyamide, are in the range which does not impair the effect of this invention for the purpose of control of adhesive force. And various additives such as an antistatic agent, a crystal nucleating agent, and an antioxidant.

The adhesion layer (X) which consists of the said olefin elastomer and / or styrene elastomer, and a resin modifier or an additive as needed can be made into the surface protection film of this invention by laminating | stacking with the said surface layer (A).

The adhesive force with respect to the acryl plate of the surface protection film of this invention becomes an index | index of the extractability and the adhesive force to a to-be-adhered body, It is preferable that it is 1N / 50mm or more, More preferably, it is the range of 3-40N / 50mm, More preferably Is in the range of 5 – 30N / 50mm. By setting it as the adhesive force of such a range, favorable feeding property can be maintained and adhesiveness to various to-be-adhered bodies can be expressed. When adhesive force is less than 1 N / 50 mm, adhesiveness to a to-be-adhered body may not be enough, and when it exceeds 40 N / 50 mm, winding property may deteriorate and it is unpreferable.

The winding force of the surface protection film of this invention refers to the peeling force at the time of extracting a roll-shaped film, and it becomes an index of drawability, but in order to keep out drawability, the said wrapping force is 2.5N / 50mm or less. Preferably, it is in the range of 0.01-2.0N / 50mm more preferably.

There is no restriction | limiting in particular about the method of laminating | stacking a surface layer (A) and the adhesion layer (X), On the surface layer film obtained by T-die shaping | molding or inflation shaping | molding previously, well-known lamination | stacking methods, such as extrusion lamination and extrusion coating, are carried out. The method of laminating an adhesive layer by this method, the method of forming each surface film and the film which form an adhesion layer independently as a film, and laminating | stacking each film by dry lamination etc. are mentioned from a viewpoint of production efficiency. The method of co-extrusion molding by providing each component of the surface layer and the adhesion layer to a multilayer extruder is preferable.

In this invention, providing at least 1 intermediate layer between a surface layer (A) and adhesion layer (X) is also performed. Although there is no restriction | limiting in particular as an intermediate | middle layer, Generally, crystalline polyolefin, such as polypropylene and polyethylene with melting | fusing point 100 or more, polyester, a polyamide, polyolefin elastomer, etc. can be used. When using an intermediate | middle layer as an adhesive layer, a modified polyolefin, a polyolefin elastomer, a styrene elastomer, a polyester elastomer, etc. are used. Among them, from the viewpoint of productivity and transparency, it is preferable to use polypropylene or polyolefin elastomer as the intermediate layer.

In addition, when the adhesive force with the surface layer A and the adhesion layer X is insufficient, the intermediate | middle layer may be comprised using adhesive materials or materials, such as a film for bonding surface layer A and adhesion layer X, as an adhesive layer. .

The thickness of the surface layer (A) in the surface protection film of this invention is 0.05-200 micrometers normally, Preferably it is 0.5-100 micrometers, More preferably, it is 1-30 micrometers, More preferably, it is 1-15 micrometers. The thickness of adhesion layer X is 0.05-50 micrometers normally, Preferably it is 0.3-40 micrometers, More preferably, it is 0.5-30 micrometers.

Therefore, the thickness of the surface protection film of this invention contains the intermediate | middle layer which may be provided as needed, and is 0.1-500 micrometers normally, Preferably it is 0.5-400 micrometers, More preferably, it is 3-300 micrometers.

As transparency of the surface protection film of this invention, the range of 20 to 90% of the haze measured at 50 micrometers according to JISK7105 is preferable, Especially preferably, it is in the range of 30 to 85%. The fish eye number (FE number) of the surface protection film of the present invention is preferably 20 or less, more preferably 10 or less, 5 or less, even more preferably 3 or less.

Example

Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

[Evaluation method]

Surface roughness (Ra): The surface protection film (it adjusted to 50 micrometers total thickness in this Example) of this invention is cured for 24 hours under conditions of 23 degreeC +/- 2 degreeC of air temperature, and 50% +/- 10% of humidity, It cut out in 50 mm angles, it was set as the film sample, and the said film sample was measured using the non-contact surface roughness meter (model number: NT-2000 SYSTEM-Veeco company make).

Adhesive force: The acrylic plate is cut into a width of 50 mm and a length of 125 mm under conditions of a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 10%, the film sample is placed on the surface of the acrylic plate, and the self-weight of the rubber roller of 2 kg By pressing the whole of the sample film. Next, the peeling force at the time of peeling (180 degree peeling) at 300 mm / min is measured, and let peel force per 50 mm width be adhesive force (N / 50mm).

Winding force: The peeling force (N / 50mm) at the time of peeling from a roll at a speed | rate of 300 mm / min is measured using a roll-shaped sample, and it is set as a winding force.

Fish eye (FE): The FE of 0.1 mm or more was counted using the offline foreign material inspection apparatus made from Ayaha Engineering, and it was set as the number of FE per unit area (piece / m <^2> ).

Haze: Based on JIS K 7105, it measured with the surface protection film (50 micrometers of total thickness in this Example) of this invention.

Example 1

Raw materials were supplied to three types of three-layer T-die molding machines with a die width of 500 mm each with a 30 mmφ single screw extruder for the surface layer and the adhesive layer and a 40 mmφ single screw extruder for the intermediate layer. The surface protection film of this invention which consists of 50 micrometers in total thickness was obtained. Table 1 shows the evaluation results of the obtained surface protection film. In addition, the raw material and compounding quantity which comprise the surface layer, intermediate | middle layer, and adhesion layer of an Example and a comparative example are shown with Table 1 with an evaluation result.

[Examples 2 to 4 and Comparative Examples 1 to 3]

The surface protection film was obtained like Example 1 except having set the resin composition of the various layers to the resin composition of Table 1. Table 1 shows the evaluation results of the obtained film.

h-PP;

  Homo polypropylene (melting point = 160 ° C, MFR = 7 g / 10 min prime polymer company (Prime Polymer Co., Ltd.))

b-PP-1;

  Propylene-ethylene block copolymer (trade name: PC684A, melting point = 160 ° C, MFR = 6 g / 10 minutes, manufactured by San Aroma, Inc.)

b-PP-2;

  Propylene-ethylene block copolymer (trade name: BC3HF, melting point = 160 ° C, MFR = 8.5 g / 10 minutes, manufactured by Nippon Polypropylene Corporation)

b-PP-3;

  Propylene-ethylene block copolymer (melting point = 160 degrees Celsius, MFR = 3 g / 10 minutes)

LDPE;

Low density polyethylene (high pressure method low density polyethylene, density = 0.917 g / cm ³ , MFR = 3 g / 10 min)

PEBR;

  Propylene ethylene 1-butene copolymer (melting point peak of melting heat 4J / g is observed at 0-200 degrees Celsius, MFR = 7 g / 10min)

SIBS;

  Styrene isobutylene copolymer (styrene isobutylene styrene triblock copolymer, Mw = 65,000, JIS-A hardness = 33), brand name: Sibstar 072T (Kaneka Corporation) My)

In Examples 1-4, adhesive force is 7-18 N / 50mm, and sufficient adhesiveness is ensured. Moreover, it turns out that winding force is 0.1-1.6N / 50mm, and it has the outstanding drawability. This is because the surface roughness Ra is an appropriate roughness of 0.47 to 0.81 µm while having sufficient adhesive force.

Moreover, in Examples 1-4, it turns out that it has the transparency which was excellent as a surface protection film in the case where it is required that the haze is 60 to 70%, and the haze is 80% or less.

On the other hand, although the adhesive force is 7-18 N / 50mm in Comparative Examples 1 and 2, and sufficient adhesiveness is ensured, it turns out that the winding force does not peel in Comparative Examples 1 and 2, and it is very inferior in feeding property. . This is because in Comparative Examples 1 and 2, the surface roughness Ra is very small at 0.25 µm and 0.05 µm, respectively, which makes peeling difficult.

In the comparative example 3, surface roughness Ra is 0.28 micrometer and has sufficient adhesive force, and winding force is 0.5N / 50mm, ie, drawability is favorable. However, when the surface layer is made of a composition of h-PP and LDPE (Comparative Example 3), the fish eye number (FE number) is large and is not suitable as a surface protective film.

Thus, from Examples 1-4 and Comparative Example 3, it is necessary that a surface layer consists of a propylene polymer.

The surface protection film of this invention is excellent in adhesive characteristic, transparency, winding property, and heat resistance, and industrial use value is very high as a protective film with an optical use, a building material use, and an automotive parts use.

Claims (3)

A surface protective film composed of at least two layers of the surface layer (A) and the adhesive layer (X), wherein the surface layer (A) is made of a propylene polymer, and the surface roughness (Ra) of the surface layer is in the range of 0.2 to 2.0 µm. Surface protection film. The method of claim 1,
The adhesive force with respect to an acryl plate is 1N / 50mm or more, The surface protection film characterized by the above-mentioned. The method of claim 1,
The pressure-sensitive adhesive layer (X) is formed of an olefin-based elastomer and / or a styrene-based elastomer.