WO2011096351A1

WO2011096351A1 - Surface protective film

Info

Publication number: WO2011096351A1
Application number: PCT/JP2011/051868
Authority: WO
Inventors: 則英井上
Original assignee: 三井化学東セロ株式会社
Priority date: 2010-02-02
Filing date: 2011-01-31
Publication date: 2011-08-11
Also published as: TW201136951A; KR20120112848A; TWI503335B; JPWO2011096351A1

Abstract

Disclosed is a surface protective film which exhibits high adhesion and excellent unwinding characteristics. The surface protective film is characterised in that: the surface protective film comprises at least two layers, which are a surface layer (A) and an adhesive layer (X); the surface layer (A) comprises 0-98 wt% of a propylene (co)polymer (a), and 2-100 wt% of an olefin (co)polymer (b) having an α-olefin with a carbon number of at least 4 as a main constituent (for the purposes of explaining the ratio of (a) to (b), the total of (a) and (b) is made 100 wt%); and the adhesive later (X) is formed from 0-80 wt% of an olefinic elastomer, and 20-100 wt% of a styrene/isobutylene copolymer (in order to explain the ratio of the olefinic elastomer to the styrene/isobutylene copolymer, the total is made 100 wt%).

Description

Surface protection film

The present invention relates to a surface protective film used for optical products, building materials, automobile parts and the like. Specifically, it has excellent adhesive properties, transparency, heat resistance, little contamination to the adherend, etc., and ease of unwinding when the film is unwound in a roll shape (hereinafter referred to as unwinding property). )).

The surface protective film is used by sticking to adherends such as resin products, metal products, glass products, etc. mainly for building materials and optical applications, and prevents them from being scratched or contaminated during transport, storage or processing. Plays. These surface protective films generally comprise a non-adhesive surface layer and an adhesive layer for adhering to the adherend. The surface layer is usually formed from a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate, or a vinyl polymer such as polyvinyl chloride.

In recent years, development of materials used for liquid crystal screens, plasma displays (PDPs), rear projection screens, etc., so-called optical products, has been progressing. The surface protective film for protecting these optical products is not only scratched or mixed with foreign matter, but also transparent enough to allow product inspection with the surface protective film applied, and suitable for application at high temperatures. Adhesive properties such as the development of adhesive strength are desired.

In addition, when a surface protection film is used for building materials or automotive parts, it may be thermoformed with the surface protection film attached, and high heat resistance that can be used as a surface protection film is required even at high temperatures. Has been.

In addition, since the surface protective film having a relatively high adhesive strength does not have a sufficient payout property, it is in a roll state in which a release film is bonded to the adhesive layer and wound up, and is applied to an adherend. The release film is peeled off and used. When such a means is employed, a large amount of release film is generated as waste, so that a surface protective film having sufficient payout property without a release film is required.

Patent Document 1 discloses a surface protective film mainly composed of a polyethylene component. However, the protective film of the publication can be applied to members for some uses, but has low adhesive strength and insufficient transparency, and has limited uses for adherends.

JP 2006-116769 A

The object of the present invention is to provide properties required as a surface protective film for protecting optical products, building material products and automobile parts during storage, transportation, processing, and inspection, in particular, adhesive properties, transparency, even at high temperatures. An object of the present invention is to provide a surface protective film excellent in heat resistance and pay-out property to the extent that it can be used as a surface protective film.

As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by a surface protective film having a surface layer made of a specific resin composition, and have completed the present invention.

That is, the present invention is a surface protective film comprising at least two layers of a surface layer (A) and an adhesive layer (X), and the surface layer (A) is a propylene-based (co) polymer (a) 0 to 98 weights. % And an olefin (co) polymer (b) having a main component of α-olefin having 4 or more carbon atoms (b) 2 to 100% by weight (in order to explain the ratio between (a) and (b) in any case) The total amount of these (a) and (b) alone is 100% by weight.) The adhesive layer (X) is 0 to 80% by weight of the olefin elastomer and 20 to 100% by weight of the styrene / isobutylene copolymer. (In either case, only olefinic elastomers and styrene / isobutylene copolymers are considered to explain the ratio between olefinic elastomers and styrene / isobutylene copolymers. To a total of 100 wt%.) Relates to a surface protective film characterized by being formed from.

Further, in the present invention, a preferred embodiment of the above surface protective film is that the olefin (co) polymer (b) mainly containing an α-olefin having 4 or more carbon atoms is a 4-methylpentene-1 polymer. The surface protective film is characterized in that the adhesive strength to the acrylic plate is in the range of 5 to 40 N / 50 mm.

The surface protective film of the present invention is excellent in adhesive properties, transparency, roll-out property from a rolled-up state, and heat resistance to the extent that it can be used as a surface protective film even in a high temperature state. It is suitable as a surface protection film for building materials and automobile parts.

Next, the present invention will be described in detail.

The surface protective film of the present invention comprises at least two layers of a surface layer (A) and an adhesive layer (X).

The surface layer (A) is formed from a composition comprising a propylene-based (co) polymer (a) and an olefin (co) polymer (b) mainly composed of an α-olefin having 4 or more carbon atoms.

Examples of the propylene-based (co) polymer (a) include a propylene homopolymer, and a random or block copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms. In addition, the description with a propylene type | system | group (co) polymer is a description which shows that both the polymer of propylene and the copolymer which consists of propylene and another monomer are included.

Examples of the α-olefin having 4 to 20 carbon atoms used in the random or block copolymer include 1-butene, 4-methylpentene-1, 1-hexene, 1-octene and the like. Examples of such a copolymer include a propylene / ethylene copolymer, a propylene / 1-butene copolymer, and a propylene / ethylene / 1-butene copolymer.

The propylene-based (co) polymer (a) has a melting point of preferably 50 to 170 ° C., more preferably 70 to 170 ° C., still more preferably 100 to 165 ° C., and more preferably 130 to 165 ° C. from the viewpoint of improving heat resistance. Is most preferred. Here, the melting point is a value measured by a differential scanning calorimeter (DSC) at a temperature rising / falling rate of 10 ° C./min.

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

The propylene-based (co) polymer (a) is not only a solid titanium catalyst mainly composed of a solid titanium compound and an alkylaluminum compound, but also a metallocene catalyst mainly composed of a metallocene compound, a geometrically constrained catalyst, etc. Is obtained by homopolymerization of propylene or copolymerization of propylene with ethylene or an α-olefin having 4 to 20 carbon atoms.

The olefin (co) polymer (b) preferably contains 50 to 100 mol%, more preferably 60 to 100 mol%, still more preferably 70 to 100 mol% of an α-olefin having 4 or more carbon atoms. Examples of the α-olefin having 4 or more carbon atoms include 1-butene, 4-methylpentene-1, 1-hexene, 1-octene, 1-decene, 1-dodecene and the like, and preferably 4-methylpentene- 1. In addition, the description with an olefin (co) polymer is a description which shows containing both the polymer of 1 type of olefin, and the copolymer of 2 or more types of olefin.

As the particularly preferred olefin (co) polymer (b) from the viewpoint of heat resistance of the surface protective film, 4-methylpentene-1 polymer, that is, 4-methylpentene-1 is 50 to 100 mol%, more preferably There is a polymer containing 60 to 100 mol%, more preferably 70 to 100 mol%. Examples thereof include 4-methylpentene-1 homopolymer and a copolymer of 4-methylpentene-1 and an α-olefin having 6 to 20 carbon atoms. By using 4-methylpentene-1 homopolymer or a copolymer of 4-methylpentene-1 and an α-olefin having 6 to 20 carbon atoms as the olefin (co) polymer (b), The surface protective film having excellent heat resistance to such an extent that it does not cause adhesiveness or film deformation and functions as a surface protective film can be obtained. Further, as olefin (co) polymer (b), 4-methylpentene-1 homopolymer, copolymer of 4-methylpentene-1 and α-olefin having 6 to 20 carbon atoms is a general-purpose olefin resin. For example, although it has a high melting point compared with a polypropylene homopolymer, it contributes to the use performance under high-temperature conditions of the entire surface protective film including not only the surface layer but also the adhesive layer. Examples of the α-olefin having 6 to 20 carbon atoms include 1-hexene, 1-octene, 1-decene and 1-dodecene.

The olefin (co) polymer (b) preferably has a melting point of 150 to 300 ° C., more preferably 180 to 280 ° C., more preferably 200, from the viewpoint of obtaining a surface protective film excellent in moldability and heat resistance. It is in the range of ~ 250 ° C.

The olefin (co) polymer (b) has an MFR measured at 230 ° C. of preferably from 0.1 to 500 g / 10 minutes, more preferably from 0.5 to 200 g / 10 minutes, from the viewpoint of processability. Preferably, it is in the range of 1 to 100 g / 10 minutes.

The surface layer (A) in the surface protective film of the present invention is composed of the propylene-based (co) polymer (a) and the olefin (co) polymer (b), and a composition comprising other components as necessary. It is formed.

The ratio of the propylene-based (co) polymer (a) and the olefin (co) polymer (b) in the composition will be described. The proportion of the propylene-based (co) polymer (a) is 0 to 98% by weight. More preferably, it is 0 to 95% by weight, more preferably 5 to 90% by weight, preferably 10 to 90% by weight, and the proportion of the olefin (co) polymer (b) is 2 to 100% by weight. Preferably, more preferably 5 to 100% by weight, more preferably 10 to 95% by weight (in each case, to explain the ratio between (a) and (b), these (a) and (b) Only 100% by weight).

In the composition, for the purpose of imparting antistatic property and weather resistance to the surface protective film of the present invention, improving transparency and improving appearance, an antistatic agent, a release agent, an antioxidant, a weathering agent, a crystal nucleus, It is also possible to add various additives such as additives, and other resin modifiers such as other crystalline polyolefins such as polyethylene and polybutene, polyesters, polyamides, and elastomers.

When an additive or a modifier is added as necessary together with the propylene-based (co) polymer (a) and the olefin (co) polymer (b), for example, after adding the additive, The film may be further kneaded with a twin screw extruder or a feeder ruder and then further processed into a film, but it is directly fed into a T-die molding machine equipped with an extruder, and the surface layer of the surface protective film of the present invention It can also be (A).

The pressure-sensitive adhesive layer (X) of the surface protective film of the present invention is composed of an olefin elastomer, a styrene / isobutylene copolymer, and other components as necessary, but the olefin elastomer and the styrene / isobutylene copolymer in the pressure-sensitive adhesive layer. The ratio of the coalescence will be described from 0 to 80% by weight of the olefin elastomer and 20 to 100% by weight of the styrene / isobutylene copolymer. Preferably, the olefin elastomer is 0 to 75% by weight and the styrene / isobutylene copolymer is 25 to 100% by weight, more preferably, the olefin elastomer is 5 to 75% by weight and the styrene / isobutylene copolymer is 25 to 95% by weight (any In this case, in order to explain the ratio between the olefin-based elastomer and the styrene / isobutylene copolymer, the total of these is 100% by weight.)

As the olefin-based elastomer, an amorphous elastomer whose melting point is not observed in the range of 0 to 200 ° C. by DSC measurement (measured at a temperature rising / falling rate of 10 ° C./min), or is observed in the range of 0 to 200 ° C. A microcrystalline elastomer in which a peak having a melting heat value of the melting point peak of 10 J / g or less is preferred, more preferably the amorphous elastomer or a microcrystalline elastomer having a melting heat value of the melting point peak of 7 J / g or less. .

The olefin-based elastomer is an α-olefin polymer or copolymer having 2 to 20 carbon atoms, or a copolymer of ethylene and an unsaturated carboxylic acid or unsaturated carboxylic acid ester. Specifically, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methylpentene-1 copolymer, ethylene / 1-octene copolymer , Propylene homopolymer, 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 / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer, etc. It can be mentioned. From the viewpoint of stability of adhesive strength with time, propylene homopolymers, propylene / ethylene copolymers, propylene / 1-butene copolymers, and propylene / ethylene / 1-butene copolymers are preferred.

Examples of styrene / isobutylene copolymers include styrene / isobutylene / styrene triblock copolymers and styrene / isobutylene diblock copolymers. The weight average molecular weight (Mw) of styrene / isobutylene copolymer measured by gel permeation chromatography (GPC) is preferably in the range of 10,000 to 300,000, more preferably in the range of 15,000 to 250,000. The range of 20,000 to 200,000 is more preferable. If Mw is smaller than 10,000 or larger than 300,000, the productivity of the surface protective film may be inferior.

The adhesive layer (X) in the surface protective film of the present invention can be formed by blending the olefin-based elastomer and / or styrene / isobutylene copolymer alone or with different compositions. Further, in the present invention, for the purpose of controlling the adhesive force, polyolefins such as polyethylene and polypropylene, acid-modified polyolefins, polyesters, polyamides and the like are used as the material constituting the adhesive layer (X) within a range that does not impair the effects of the present invention. And various additives such as an antistatic agent, a crystal nucleating agent, and an antioxidant.

The adhesive layer (X) comprising the olefin elastomer and / or styrene / isobutylene copolymer, and a resin modifier or additive added as necessary, is laminated with the surface layer (A), The surface protective film of the present invention can be obtained.

The method for laminating the surface layer (A) and the adhesive layer (X) is not particularly limited, but extrusion lamination and extrusion coating are carried out on the film for forming the surface layer obtained by T-die molding or inflation molding in advance. Examples include a method of laminating an adhesive layer by a known laminating method, and a method of laminating each film by dry lamination after forming the surface layer and the film forming the adhesive layer independently as a film. However, from the viewpoint of production efficiency, a method in which each component of the surface layer and the adhesive layer is subjected to coextrusion molding using a multilayer extruder is preferable.

In the present invention, at least one intermediate layer is also provided between the surface layer (A) and the adhesive layer (X). Moreover, when the adhesive force with the surface layer (A) and the pressure-sensitive adhesive layer (X) is insufficient, an adhesive or an adhesive layer may be used as the intermediate layer.

The intermediate layer is not particularly limited, but generally, a crystalline polyolefin such as polypropylene or polyethylene having a melting point of 100 ° C. or higher, polyester, polyamide, polyolefin elastomer, or the like can be used. When the intermediate layer is used as an adhesive layer, modified polyolefin, polyolefin elastomer, styrene elastomer, polyester elastomer, or the like is used. Among these, from the viewpoint of productivity and transparency, it is preferable to use polypropylene or polyolefin elastomer as the intermediate layer.

When the adhesive force between the surface layer (A) and the pressure-sensitive adhesive layer (X) is insufficient, the intermediate layer is an adhesive or a film for bonding the surface layer (A) and the pressure-sensitive adhesive layer (X). The material may be configured as an adhesive layer.

The thickness of the surface layer (A) in the surface protective film of the present invention is usually 0.05 to 200 μm, preferably 0.5 to 100 μm, more preferably 1 to 30 μm, and still more preferably 1 to 15 μm. The thickness of the pressure-sensitive adhesive layer (X) is usually 0.05 to 50 μm, preferably 0.3 to 40 μm, more preferably 0.5 to 30 μm.

Therefore, the thickness of the surface protective film of the present invention is usually 0.1 to 500 μm, preferably 0.5 to 400 μm, more preferably 3 to 300 μm, including an intermediate layer which may be provided if necessary.

By using the surface layer (A), the pressure-sensitive adhesive layer (X) and the intermediate layer in the above preferred form, a surface protective film excellent in unwinding properties can be obtained, and can be suitably used particularly for optical applications.

The adhesive strength of the surface protective film of the present invention to acrylic is preferably in the range of 5 to 40 N / 50 mm, more preferably in the range of 5 to 35 N / 50 mm, more preferably in the range of 6 to 30 N / 50 mm. . When the adhesive strength is less than 5 N / 50 mm, the adherence to the adherend is often insufficient, and when it exceeds 40 N / 50 mm, the feeding property is often lowered.

The unwinding force of the surface protective film of the present invention, that is, the peel strength when the film is unwound at a constant speed from the state in which the surface protective film is wound in a roll, is an index of the unwinding property. With respect to the surface protective film of the present invention, when the rewinding force is 2.5 N / 50 mm or less, preferably in the range of 0.01 to 2.0 N / 50 mm, excellent payout property can be obtained.

As the transparency of the surface protective film of the present invention, the haze measured with a total thickness of 50 μm according to JISK7105 is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[Evaluation method]
Adhesive strength: Acrylic plate is cut into a width of 50 mm and a length of 125 mm under conditions of an air temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 10%, a film sample is placed on the surface of the acrylic plate, and a 2 kg rubber roller The whole sample film is pressed onto the acrylic plate by its own weight. Next, the peel force when peeled at a speed of 300 mm / min (180 degree peel) is measured, and the peel force per 50 mm width is defined as the adhesive strength (N / 50 mm).
Unwinding force: Using a roll-shaped sample, the peeling force (N / 50 mm) when peeling from the roll at a speed of 300 mm / min is measured and used as the unwinding force.
Haze: Measured with a film having a total thickness of 50 μm according to JIS K7105.
[Example 1]
The following raw materials were supplied to a three-layer three-layer T-die molding machine having a die width of 500 mm, which was equipped 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. ), An adhesive layer (X) thickness of 10 μm, an intermediate layer thickness of 30 μm, and a total thickness of 50 μm were obtained. Each evaluation result of the obtained film is shown in Table 1.

Surface layer:
Homopolypropylene (brand name: F107BV, melting point = 160 ° C., MFR = 7 g / 10 min, manufactured by Prime Polymer Co., Ltd.) 70% by weight
4-methylpentene-1 polymer (trade name: TPX, brand name: RT18, melting point = 237 ° C., MFR = 26 g / 10 min, manufactured by Mitsui Chemicals) 30% by weight
Middle layer:
Homopolypropylene (melting point = 160 ° C., MFR = 7 g / 10 min) 100% by weight
Adhesive layer:
Propylene / ethylene / 1-butene copolymer (a melting point peak with a heat of fusion of 4 J / g is observed in the range of 0 to 200 ° C., MFR = 7 g / 10 min) 60% by weight
Styrene / isobutylene copolymer (styrene / isobutylene / styrene triblock copolymer, Shibster 072T (manufactured by Kaneka)) 40% by weight
[Examples 2-8, Comparative Examples 1-2]
A surface protective film was obtained in the same manner as in Example 1 except that the resin compositions of the various layers were changed to the resin compositions shown in Table 1. Table 1 shows the evaluation results of the obtained film.

h-PP;
Homopolypropylene (melting point = 160 ° C., MFR = 7 g / 10 min, manufactured by Prime Polymer Co., Ltd.)
PB;
Homopolybutene (melting point = 120 ° C, MFR = 2 g / 10 min)
TPX;
4-methylpentene-1 polymer (trade name: TPX, brand name: RT-18, melting point = 237 ° C., MFR = 26 g / 10 min, manufactured by Mitsui Chemicals)
PEBR;
Propylene / ethylene / 1-butene copolymer (A melting point peak of 4 J / g of heat of fusion is observed in the range of 0 to 200 ° C., MFR = 7 g / 10 min)
SIBS;
Styrene / isobutylene copolymer (styrene / isobutylene / styrene triblock copolymer, Mw = 65,000, JIS-A hardness = 33, Shibster 072T (manufactured by Kaneka Corporation))
HSBR;
Styrene-butadiene copolymer hydride (Dynalon 1320P (manufactured by JSR))
The surface layers of Examples 1 to 4 and 6 to 8 are h-PP, that is, 70 to 30% by weight of propylene-based (co) polymer (a) and 30 to 30% of TPX, that is, olefin (co) polymer (b). It is composed of 70% by weight. The adhesive layer is composed of PEBR, that is, 0 to 80% by weight of an olefin elastomer, and SIBS, that is, 20 to 100% by weight of a styrene / isobutylene copolymer. It can be seen that the adhesive strength is 5 to 21 N / 50 mm, and the adhesive strength is sufficient as a surface protective film. In addition, the rewinding force is 2.4 N / 50 mm in both cases, and both have excellent adhesive force and at the same time have a feeding property.

Also, regarding the transparency, the hazes of Examples 1 to 4 are all 70% or less, and have transparency suitable as a surface protective film. Furthermore, when TPX is used for the surface layer, the haze of the surface protective film is 5%, indicating that the transparency is particularly excellent.

On the other hand, in Comparative Example 1, the pressure-sensitive adhesive layer has PEBR of 60% by weight and SIBS of 40% by weight. However, since the surface layer is composed only of h-PP, the adhesive force between the surface layer and the pressure-sensitive adhesive layer is The rewind force is too large to measure. Therefore, the film of Comparative Example 1 does not have good drawability, and is not practical as a surface protective film.

In Comparative Example 2, the surface layer is composed of 70% by weight of h-PP and 30% by weight of TPX, while the adhesive layer is composed of 60% by weight of PEBR and 40% by weight of HSBR. . The unwinding force is 3.6 N / 50 mm, which is a very large value. Therefore, the film of Comparative Example 2 does not have a good pay-out property and is not practical as a surface protective film.

From the above Examples 1 to 8 and Comparative Examples 1 and 2, the surface protective film of the present invention has not only a sufficient transparency as a surface protective film, but also sufficient adhesive force to the adherend, and excellent feeding It turns out that it has sex.

The surface protective film of the present invention is excellent in adhesive properties, transparency, unwinding property and heat resistance, and has an extremely high industrial utility value as a protective film for optical use, building material use and automotive part use.

Claims

A surface protective film comprising at least two layers, a surface layer (A) and an adhesive layer (X), wherein the surface layer (A) is 0 to 98% by weight of a propylene-based (co) polymer (a) and has 4 or more carbon atoms 2 to 100% by weight of olefin (co) polymer (b) based on α-olefin of the above (in order to explain the ratio between (a) and (b), these (a) and (b) The adhesive layer (X) is 0 to 80% by weight of the olefin elastomer and 20 to 100% by weight of the styrene / isobutylene copolymer (both the olefin elastomer and the styrene / isobutylene copolymer). In order to explain the ratio between the polymers, the total amount of these alone is 100% by weight)).
2. The surface protective film according to claim 1, wherein the olefin (co) polymer (b) mainly composed of an α-olefin having 5 or more carbon atoms is a 4-methylpentene-1 polymer.
The surface protective film according to claim 1 or 2, wherein the adhesive strength to the acrylic plate is in the range of 5 to 40 N / 50 mm.