KR20110123724A - Surface protection film for prism sheet, and process for production thereof, and prism sheet with the film put thereon - Google Patents

Abstract

(Problem) An object of the present invention is to provide a surface protection film for a prism sheet, in which the developing force from the roll is small and the release layer adhered to the pressure-sensitive adhesive layer does not lower the adhesive force well.
(Solution) The thickness is mainly composed of (A) saturated fatty acid bisamide, which is produced by co-extruding molding raw material A containing saturated fatty acid bisamide and polyolefin resin, and molding raw material B containing styrene elastomer. The surface protection film for prism sheets by which the mold release layer which is -100 nm, the polyolefin resin layer as a base material layer, and the styrene-type elastomer layer as (C) adhesive layer were laminated | stacked.

Description

SURFACE PROTECTION FILM FOR PRISM SHEET, AND PROCESS FOR PRODUCTION THEREOF, AND PRISM SHEET WITH THE FILM PUT THEREON

This invention relates to the surface protection film for prism sheets, its manufacturing method, and the prism sheet to which it was affixed.

The prism sheet has a plurality of triangular prism prisms serving as a lens surface on one side thereof, so that the brightness of the liquid crystal display can be improved. In order not to damage a prism, a surface protection film is affixed and protected by the prism provided in the surface of a prism sheet.

Since the prism sheet with which the surface protection film was affixed may be exposed to high temperature during conveyance and storage, the adhesive used for a surface protection film uses the rubber type adhesive with a small rise of the adhesive force by heating and time-lapse | temporality.

On the other hand, the surface protection film is treated as a roll. Rubber-based adhesives generally have a problem in that the force (development force) required for feeding out from the roll is large, so that the development force gradually increases when the roll is stored for a long time.

Since the surface protection film with a large development force is fed out from the roll in the state where the surface protection film is tensioned, the point where the surface protection film is lifted from the adhesive surface with the prism sheet when the surface protection film is affixed to the prism sheet (so-called "lifting") There is a problem that occurs). For this reason, the surface protection film with small development force (so-called "light development") was calculated | required.

When the release layer is formed on the surface protective film, the development force can be reduced. However, when the release agent is peeled off from the substrate layer and transferred to the pressure-sensitive adhesive layer, there is a problem that the adhesive force of the surface protection film is lowered. When the surface protection film is applied to the lens surface of the prism sheet, the contact area between the unevenness of the lens surface and the pressure-sensitive adhesive layer of the surface protection film is small, so that the release agent transferred to the pressure-sensitive adhesive layer reduces the contact area between the pressure-sensitive adhesive layer and the unevenness of the lens surface. By reducing, the adhesion of the surface protective film is greatly reduced. In patent document 1, the surface protection film which a mold release layer does not transfer easily to an adhesive layer is proposed.

Japanese Unexamined Patent Publication No. 2003-41216

However, the release layer of the surface protection film of patent document 1 is formed by apply | coating a mold release agent to a base material. When the release agent is applied using an organic solvent, the load on the environment is large. Moreover, when apply | coating the aqueous dispersion of a mold release agent, a drying process is needed. When apply | coating the ultraviolet curable resin liquid of a mold release agent, an ultraviolet irradiation device is required.

An object of the present invention is to provide a surface protective film for a prism sheet, which has a small development force from a roll and which does not degrade well even when a release layer is attached to the pressure-sensitive adhesive layer.

Moreover, another object of this invention is to provide the manufacturing method of the surface protection film for prism sheets of this invention.

This invention provides the prism sheet with which the surface protection film of the following [1]-[6], the manufacturing method of the surface protection film of the following [7], and the surface protection film of the following [8] were stuck.

[One]

Molding raw material A containing a saturated fatty acid bisamide and a polyolefin resin, and

Produced by co-extrusion of the molding raw material B containing a styrene-based elastomer,

(A) A release layer mainly composed of saturated fatty acid bisamides having a thickness of 1 to 100 nm,

(B) a polyolefin resin layer as a substrate layer, and

(C) The surface protection film for prism sheets with which the styrene-type elastomer layer as an adhesive layer was laminated | stacked.

[2]

The surface protection film for prism sheets of Claim 1 in which the said molding raw material A contains 1-4 weight part of saturated fatty acid bisamide with respect to 100 weight part of polyolefin resins.

[3]

The surface protection film for prism sheets as described in [1] or [2] whose saturated fatty acid bisamide is ethylene bis stearic acid amide, methylene bis stearic acid amide, or hexamethylene bis stearic acid amide.

[4]

Surface protection film for prism sheets as described in [1] or [2] whose saturated fatty acid bisamide is saturated fatty acid aromatic bisamide.

[5]

The surface protection film for prism sheets in any one of [1]-[4] in which an intermediate | middle layer is formed between the said base material layer and the said adhesive layer.

[6]

The surface protection film for prism sheets as described in [5] whose said intermediate | middle layer contains a saturated fatty acid bisamide and is a mixture of polyolefin resin and styrene elastomer.

[7]

(A) Mold release layer of thickness 1-100 nm which mainly consists of saturated fatty-acid bisamide,

(B) a polyolefin resin layer which is a base material layer,

(C) As a manufacturing method of the surface protection film for prism sheets which the styrene-type elastomer layer which is an adhesive layer laminated | stacked in this order,

The manufacturing method of the surface protection film for prism sheets which co-extrudes the shaping | molding raw material A containing 1-4 weight part of saturated fatty acid bisamide, and the shaping | molding raw material B containing styrene-type elastomer with respect to 100 weight part of polyolefin resin.

[8]

A prism sheet having a plurality of triangular prism prisms on a lens surface, and

The release layer which consists of (A) saturated fatty-acid bisamide mainly affixed on the said lens surface is 1-100 nm in thickness, (B) polyolefin resin layer as a base material layer, and

(C) the surface protection film for prism sheets in which the styrene-type elastomer layer as an adhesive layer was laminated | stacked,

A prism sheet with a surface protection film affixed to it, wherein the depth of penetration of the prism into the pressure-sensitive adhesive layer is 0.3 µm or more.

ADVANTAGE OF THE INVENTION According to this invention, the surface protective film for prism sheets which the development force from a roll is small and adhesive force does not fall easily even if a release layer adheres to an adhesive layer can be provided.

Moreover, according to this invention, the manufacturing method which manufactures the surface protection film for prism sheets with which the very thin mold release layer was formed can be provided.

The surface protection film for prism sheet of this invention,

(A) Release layer whose thickness is 1-100 nm mainly consisting of saturated fatty acid bisamide.

(B) a polyolefin resin layer serving as a base material layer, and

(C) The styrene-type elastomer layer used as an adhesive layer is laminated | stacked in this order.

Although the thickness of the surface protection film for prism sheets of this invention is not specifically limited, The minimum is 12 micrometers normally, Preferably it is 20 micrometers, The upper limit is 100 micrometers normally, Preferably it is 60 micrometers, More preferably, 50 micrometers More preferably 45 µm.

(A) release layer

The release layer consists mainly of saturated fatty acid bisamides. Here, "consisting mainly of" means that the release layer is formed of the saturated fatty acid bisamide bleed out from the olefin resin layer. Moreover, more specifically, it means that content of saturated fatty-acid bisamide is 90 weight% or more of the whole mold release layer.

As saturated fatty-acid bisamide, For example, saturated fatty-acid aliphatic bisamide, such as ethylene bis stearic acid amide, methylene bis stearic acid amide, and hexamethylene bis stearic acid amide; And

Saturated fatty acid aromatic bisamides such as m-xylylenebisstearic acid amide and N-N'-distearyl isophthalic acid amide are preferred. In saturated fatty acid aliphatic bisamide, ethylene bis stearic acid amide is more preferable. Moreover, in saturated fatty acid aromatic bisamide, m-xylylene bis stearic acid amide is more preferable.

These saturated fatty acid bisamides may be used alone or in combination of two or more thereof.

Moreover, you may use together another mold release agent.

The release layer has a thickness of 1 to 100 nm.

The lower limit of the thickness is preferably 5 nm, more preferably 7 nm, even more preferably 9 nm. On the other hand, the upper limit of the thickness is preferably 80 nm, more preferably 60 nm, still more preferably 40 nm.

When the surface protection film for prism sheets of this invention was made into the form of a roll, since the said release layer contacted an adhesive layer and the thickness of a release layer is controlled to 100 nm or less even if it transfers to the surface of an adhesive layer, a prism sheet If the ridge of the surface prism penetrates through the release layer and the depth of the prism adhering to the pressure-sensitive adhesive is 0.3 µm or more, there is no occurrence of lifting and the like, and the adhesive strength can be secured practically.

When the thickness of a release layer is 100 nm or less, it adheres to an adhesive layer at the time of sticking to a prism sheet by the ridge of the triangular prism of a prism sheet when rewinding a surface protection film from a roll (that is, transfer | transfer) ), The release layer is penetrated, and the prism sheet and the pressure-sensitive adhesive layer are in contact with each other. Thereby, sufficient adhesive force is obtained practically.

On the other hand, when the thickness of the release layer is 1 nm or more, the developing force from the roll can be sufficiently reduced.

The thickness of a release layer is calculated | required by the following method. The surface protection film for prism sheets of this invention is dyed with ruthenium tetraoxide, and a release layer and a base material layer are dyed and divided using the difference of the ease of dyeing. The resin sample which enclosed the surface protection film was repeatedly thinly cut using the ultramicrotome (REICHERT ULTRACUT S made by Leica Corporation) which set the slice thickness to 70 nm, and several thin film pieces are produced. Among thin film pieces, the thin film piece for observation which can observe the cross section of a release layer and a base material layer is selected using a transmission electron microscope. The thin film piece for observation was observed using the transmission electron microscope, and the thickness of the release layer was measured in three places. The average value of the measured values is taken as the thickness of the release layer.

(B) base material layer

The base material layer consists of polyolefin resin.

The mold release layer of the surface protection film for prism sheets of this invention is formed by bleeding out a mold release agent from a base material layer. In the base material layer, saturated fatty acid bisamide added to the polyolefin resin in order to form the release layer remains.

Examples of the polyolefin resin include low density polyethylene resins, medium density polyethylene resins, high density polyethylene resins, linear low density polyethylene resins, ethylene-α-olefin copolymer resins, ethylene-ethyl acrylate copolymer resins, ethylene-vinyl acetate copolymer resins, Ethylene-methylacrylate copolymer resins, ethylene-n-butylacrylate copolymer resins, and polypropylene resins, and mixtures thereof.

Such resin may contain the additive normally added to resin. As an additive, antioxidant, a ultraviolet absorber, an antioxidant, etc. are mentioned. The amount of the additive is usually 5% by weight or less, preferably 3% by weight or less, based on the entire resin.

The thickness of a base material layer can be suitably adjusted with the raw material of a prism sheet, or the shape of a prism, and it is generally set to 4-80 micrometers, Preferably it is set to 20-50 micrometers.

(C) pressure-sensitive adhesive layer

The pressure-sensitive adhesive layer contains a styrene elastomer.

It is preferable that an adhesive layer mainly contains a styrene-type elastomer, and also contains a tackifier. The main body here means to occupy the most weight among all the components of an adhesive layer, Preferably it means that it contains 50 weight% or more.

It is preferable that the styrene-type elastomer used by this invention is the following polymer (iii), the following polymer (ii), or a mixture thereof.

"Polymer" includes the following polymer block A and the following polymer block B, in general formula [AB] n (wherein A is polymer block A, B is polymer block B, and n is 1-3). Copolymer (I) having a structure represented by the above) or a hydrogenated product thereof. As apparent from the point where "n" represents an integer of 1 to 3, as the "structure represented by the formula [A-B] n", for example, structures represented by A-B, A-B-A-B, and A-B-A-B-A-B are mentioned. In these block copolymers, A and B may be the same respectively in repetition, and may differ.

"Polymer (ii)" includes the following polymer block A and the following polymer block B, and the general formula ABA (a symbol in the formula represents the same meaning as above) or a general formula (AB) xY (wherein x is 2 or more) An integer, Y represents a coupling agent residue, and the other symbols represent the same meanings as above)

It is a copolymer (II) which has a structure shown by this, or its hydrogenated substance.

As a styrene-type elastomer, the weight ratio of the total amount of the polymer block A and the total amount of the polymer block B which is a mixture of the said polymer (iii) and the said polymer (ii), and is contained in the said polymer (iii) and the said polymer (ii) is 5 The mixture in the range of: 95-25: 75 is preferable.

"Polymer block A" is a polymer block in which aromatic alkenyl compound units are continuous and mainly contain aromatic alkenyl compound units.

"Polymer block B" is an aromatic alkenyl-conjugated diene copolymer block in which a conjugated diene compound unit and an aromatic alkenyl compound unit are randomly included.

An "aromatic alkenyl compound unit" is a repeating unit derived from an aromatic alkenyl compound. As an "aromatic alkenyl compound", for example, styrene, tert-butyl styrene, (alpha) -methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1, 1- diphenylethylene, vinyl naphthalene, vinyl Anthracene, N, N-diethyl-p-aminoethylstyrene, vinylpyridine and the like.

As a "conjugated diene compound", for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-octadiene, 1 , 3-hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, myrcene, chloroprene and the like.

Although the thickness in particular of an adhesive layer is not restrict | limited, It is 2-20 micrometers, Preferably it is 3-15 micrometers.

The pressure-sensitive adhesive layer of the present invention usually contains a tackifier.

Examples of the tackifier include aliphatic copolymers, aromatic copolymers, petroleum resins such as aliphatic and aromatic copolymers and alicyclic copolymers, coumarone-indene resins, terpene resins, and terpene phenols. What is generally used for an adhesive, such as rosin-type resin, such as resin, polymerization rosin, (alkyl) phenol type resin, xylene resin, or these hydrogenated substances, can be used without a restriction | limiting in particular. As for the softening point of a tackifier, it is more preferable to use what is 90-140 degreeC. These tackifiers may be used independently and may use 2 or more types together. Moreover, in order to improve peelability, weather resistance, etc., it is more preferable to use hydrogenated resin as a tackifier. Moreover, you may use the commercially available tackifier as a mixture with an olefin resin.

It is preferable that a tackifier is compatible with the polymer block B which has a conjugated diene compound unit or a hydrogenated conjugated diene compound unit.

A tackifier is used in the quantity which can prevent full residue, when peeling a surface protection film from a to-be-adhered body. For example, as for the compounding ratio of a tackifier, 5-50 weight is preferable with respect to 100 weight part of styrene-type elastomers, More preferably, it is 20-40 weight part. The blending ratio is different depending on the type of the tackifier. For example, in the case of the tackifier having a softening point of 90 to 140 ° C., 15 to 40 weight is preferable, and more preferably 100 parts by weight of the styrene-based elastomer. Is 20 to 30 parts by weight. If the amount of the tackifier is within this range, even if the surface protective film is affixed to the prism sheet for a long time, the adhesive force does not decrease well, and the surface protective film bonded to the prism sheet is hard to lift.

In an adhesive layer, well-known additives, such as a softener, antioxidant, an adhesion improvement agent, can be mix | blended as needed, for the purpose of control of adhesive force, etc. as needed.

As the softener, for example, a low molecular weight diene polymer, polyisobutylene hydrogenated polyisoprene, hydrogenated polybutadiene, paraffinic process oil, naphthenic process oil, aromatic process oil, castor oil, tall oil, natural oil And liquid polyisobutylene resins, polybutenes, or hydrogenated products thereof. These softeners may be used independently and may use 2 or more types together.

It does not specifically limit as antioxidant, For example, a phenolic antioxidant (for example, monophenolic antioxidant, bisphenolic antioxidant, high molecular type phenolic antioxidant), sulfur type | system | group antioxidant, phosphorus antioxidant, etc. are mentioned, for example. have.

Examples of the anti-adhesion inhibitor include fatty acid amides, long chain alkyl grafts of polyethyleneimine, soybean oil modified alkyd resins (manufactured by Arakawa Chemical Co., Ltd., trade name "Arachid 251"), tall oil modified alkyd resins (manufactured by Arakawa Chemical Co., Ltd., brand name "Arachid 6300"). Etc. can be mentioned.

(D) the middle layer

The surface protection film for prism sheets of this invention may further contain an intermediate layer between the said base material layer and the said adhesive layer.

The release layer is formed by bleeding out on the surface in the process of solidifying by contacting the surface of the substrate layer (the opposite side of the adhesive layer) melted immediately after coextrusion with the cooling roll. At this time, saturated fatty-acid bisamide also bleeds out on the surface on the opposite side to the release layer of the base material layer. When this layer of saturated fatty acid bisamide is in contact with the pressure-sensitive adhesive layer, the bonding force between the base material layer and the pressure-sensitive adhesive layer may decrease. The intermediate layer has a function of preventing a decrease in this bonding force.

Although the intermediate | middle layer should just be resin which can couple | bond with a base material layer and an adhesive material layer, the layer which consists of polyolefin resin is preferable.

Preferably, the polyolefin resin in the intermediate layer contains a saturated fatty acid bisamide and a styrene elastomer. You may manufacture such an intermediate | middle layer using the cutting | edge material of the surface protection film for prism sheets.

<Manufacturing Method>

The surface protection film for prism sheets of this invention is manufactured by co-extruding the molding raw material A which consists of polyolefin resin containing saturated fatty-acid bisamide, and the molding raw material B containing styrene-type elastomer.

In addition, saturated fatty acid bisamide is normally synthesized by dehydration condensation reaction of diamine and saturated fatty acid. For this reason, saturated fatty acid bisamide may contain diamine and saturated fatty acid as an impurity. According to the examination of the present inventors, in connection with the characteristic of the manufacturing method of the surface protection film for prism sheets of this invention which forms a mold release layer by bleed-out, the above-mentioned diamine and saturated fatty acid are the surface for the prism sheet of this invention. It has been found to contaminate a manufacturing apparatus at the time of manufacture of a protective film. Therefore, it is preferable that the saturated fatty acid bisamide used for this invention has a low content rate of diamine and saturated fatty acid.

Molding raw material A and molding raw material B can be prepared by mixing each component by a well-known method, respectively. For example, in the case of the molding raw material A, specifically, it can prepare by pelletizing polyolefin resin containing saturated fatty acid amide by a twin screw extruder.

The thickness of the mold release layer formed in the surface of a base material layer can be adjusted by adjusting the quantity of the saturated fatty acid bisamide which molding raw material A contains. The lower limit of the amount of saturated fatty acid bisamide contained in the molding raw material A is preferably 1 part by weight, more preferably 1.5 parts by weight with respect to 100 parts by weight of the polyolefin resin in order to form a release layer by bleeding out. to be. On the other hand, the upper limit of the amount of saturated fatty acid bisamide contained in the molding raw material A is a viewpoint of obtaining sufficient adhesive force with the prism sheet by forming a release layer of a suitable thickness, and suppressing the release of the release layer from being peeled off to the forming roll. From a viewpoint, with respect to 100 weight part of polyolefin resin, Preferably it is 4 weight part, More preferably, it is 2-3 weight part.

The molding raw material A which consists of polyolefin resin containing saturated fatty-acid bisamide, and the molding raw material B which contains a styrene-type elastomer are co-extruded by T-die method by two or more multilayer extruders, for example. Then, the resin side which extruded the molding raw material A is quenched with a cooling roll. As a result, a multilayer film is obtained.

Extrusion temperature becomes like this. Preferably it is 160-230 degreeC.

By coextrusion, a base material layer and an adhesive layer are formed first.

Subsequently, the base material layer immediately after coextrusion contacts a cooling roll, and the release fatty acid layer is formed by bleeding out the saturated fatty acid bisamide contained in the shaping | molding raw material A to the base material layer surface by itself.

When 1-4 weight part of saturated fatty-acid bisamide is contained in polyolefin resin, a mold release layer of 1-100 nm is formed in the surface of a base material layer.

The surface protection film of this invention shape | molded in this way is normally cooled by a cast roll, wound up by the winding roll, and stored as a roll.

The cast roll temperature of the thickness of a mold release layer is set to 20-90 degreeC. The release layer of the present invention is a layer formed on the surface of the substrate layer opposite to the pressure-sensitive adhesive layer.

<Surface protection film>

As mentioned above, the surface protection film for prism sheets of this invention is usually wound up and stored as a roll. At this time, the release layer contacts the adhesive face of the wound adhesive layer. When this roll is unfolded and affixed with a prism sheet, a part of mold release layer is transferred to the surface of an adhesive surface. Usually, although the adhesive force of a surface protection film falls large by transfer of a release layer, in the surface protection film of this invention, the ridgeline of the prism of a prism sheet penetrates the release layer to which it was transferred. Thereby, even if a mold release layer is transcribe | transferred, the adhesive force of an adhesive layer is exhibited.

(Depth to dig)

It is preferable that the surface protection film of this invention is 0.3 micrometer or more in depth in the prism penetration of the prism sheet to the adhesive layer. Thereby, moderate adhesive force is exhibited. Although the upper limit of the depth to dig in is not specifically limited, Usually, it is 2 micrometers or less.

The depth to dig is affixed at a speed | rate of 300 mm / min using a 2 kg pressurized rubber roller in the environment of room temperature 23 degreeC, and 50% of a relative humidity, and after leaving it for 30 minutes in that state, a surface protection film is affixed. The obtained prism sheet is frozen using a frozen microtome, the cut section is observed using a scanning electron microscope, and is a numerical value measured.

The depth to dig can be adjusted by adjusting the shear modulus and thickness of the adhesive layer of the surface protection film of this invention according to the ridge line size of the prism of the triangular pillar of the prism sheet to which the surface protection film of this invention is applied.

From this viewpoint, the shear modulus (23 ° C.) of the pressure-sensitive adhesive layer is preferably 5 × 10 ⁶ or less. However, from the viewpoint of preventing the occurrence of pool residues, the shear modulus is preferably 5 × 10 ⁴ or more.

Moreover, from this viewpoint, the thickness of an adhesive layer becomes like this. Preferably it is 4 micrometers or more. However, from the viewpoint of cost, the thickness is preferably 15 µm or less.

(Development power)

The roll of the surface protection film of this invention can be easily rewound. The developing force at a speed of 20 m / min in a roll having a width of 50 mm is preferably 3.5 N or less, more preferably 2 N or less. By setting it as such a development force, even when the width | variety of a roll exceeds 1000 mm, the sound which generate | occur | produces at the time of deployment can be reduced, and generation | occurrence | production of the lifting after affixing on a prism sheet can be prevented.

(Adhesion time-lapse adhesive force)

The surface protection film of this invention, Preferably, the sticking time lapse adhesive force in 23 degreeC measured on the following conditions is 0.05-0.50 N / 25mm.

[Condition]

After producing a surface protection film, the surface protection film of width 25mm is affixed so that the lens surface of a prism sheet may be covered within 3 days. A prism sheet composed of an acrylic resin having a thickness of 130 μm and having a pitch of a prism of 50 μm and a height of 25 μm is used. A surface protective film is affixed at a speed | rate of 300 mm / min using a 2 kg compression rubber roller in the environment of 23 degreeC of room temperature, and 50% of a relative humidity. After leaving for two weeks in an environment of a room temperature of 23 ° C. and a relative humidity of 50%, the surface protection film was peeled at a rate of 300 mm / min in accordance with JIS Z0237 to measure 180 ° peel strength. The direction to peel a surface protection film shall be a ridgeline direction of a prism. The 180 degree peeling strength measured in this way is made into the sticking time-lapse adhesive force at 23 degreeC.

<Prism Sheet with Surface Protection Film>

The surface protection film for prism sheets of this invention is affixed on the lens surface of a prism sheet.

Prism sheet with a surface protection film which affixed the surface protection film for prism sheets of this invention, ie

A prism sheet having a plurality of triangular prism prisms on the lens surface, and a release layer having a thickness of 1 to 100 nm mainly composed of (A) saturated fatty acid bisamide affixed to the lens surface, (B) as a substrate layer Polyolefin resin layer, and

(C) the surface protection film for prism sheets in which the styrene-type elastomer layer as an adhesive layer was laminated | stacked,

A prism sheet with a surface protective film is also an aspect of the present invention, wherein a depth of the prism into the pressure-sensitive adhesive layer is 0.3 µm or more.

As a prism sheet which affixes the surface protection film for prism sheets of this invention, for example, the prism which adjoins in the several prism of the triangular pillar which has a vertex angle whose vertices of a ridgeline in the lens surface is about 90 degrees. It is mentioned that the distance between peaks of is about 10-1000 micrometers.

As a prism sheet with which such a surface protection film was affixed,

A prism sheet having a plurality of triangular prism prisms on a lens surface, and

The prism sheet as described in any one of said [1]-[6] attached to the lens surface of the said prism sheet,

The prism sheet in which the surface protection film is affixed is preferable that the depth which the said prism penetrates into the said adhesive layer is 0.3 micrometer or more.

Example

Below, the surface protection film of this invention is demonstrated in detail based on an Example and a comparative example. In addition, this invention is not limited to a following example.

(Example 1)

As a molding material A, a mixture consisting of 100 parts by weight of polypropylene `` Y900GV (manufactured by Prime Polymer) '' and 1 part by weight of ethylene bis stearic acid amide `` Alpha H50F (manufactured by Nichi Oil Company) '', which is a saturated fatty acid bisamide, and molding material B 100 parts by weight of a styrene-based elastomer `` Dynaron 1320P (manufactured by JSR) '', 20 parts by weight of a tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.), and an antioxidant" irganox 1010 (manufactured by Chiba Specialty Chemicals) " The mixture which consists of 1 weight part was coextruded by the T die method on condition of the following, and the surface protection film was produced. As for the surface protection film, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesive layer was 6 micrometers.

The thickness of the release layer of the surface protection film was 6 nm.

<Condition>

Extrusion temperature: 200 ℃

Cast roll temperature: 25 ℃

<Measurement Method of Thickness of Release Layer>

The thickness of the release layer was determined by the following method. The surface protection film for prism sheets was dyed with ruthenium tetraoxide, and the release layer and the base layer were dyed by dividing using the difference in the ease of dyeing. The resin sample which enclosed the surface protection film was repeatedly thinly cut using the ultramicrotome (REICHERT ULTRACUT S made by Leica Corporation) which set the slice thickness to 70 nm, and several thin film pieces are produced. The thin film piece for observation which can observe the cross section of a release layer and a base material layer was selected using the transmission electron microscope (JEM-2100 by JEOL company) among several thin film pieces. The thin film piece for observation was observed using the transmission electron microscope (JEM-2100 by JEOL company), and the thickness of the release layer was measured in three places. The average value of the measured values is taken as the thickness of the release layer.

(Example 2)

A surface protective film was produced in the same manner as in Example 1 except that the amount of ethylenebisstearic acid amide was 1.5 parts by weight. As for the surface protection film, the thickness of the base material layer was 34 micrometers, the thickness of the adhesion layer was 6 micrometers, and the thickness of the release layer was 9 nm.

(Example 3)

A surface protective film was produced in the same manner as in Example 1 except that the amount of ethylenebisstearamide was 3 parts by weight. As for the surface protection film, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesion layer was 6 micrometers. Moreover, the thickness of the mold release layer of the surface protection film was 80 nm.

(Example 4)

The cutting | edge material which arose when trimming both ends of the surface protection film of this invention was shape | molded by the pellet using the twin screw extruder.

As a molding material A, a mixture consisting of 100 parts by weight of polypropylene `` Y900GV (manufactured by Prime Polymers) '' and 1 part by weight of ethylenebisstearic acid amide `` Alpha H50F (manufactured by Nichi Oil) '', which is a saturated fatty acid bisamide, is formed. As a raw material to be used, a mixture consisting of 70 parts by weight of polypropylene `` Y900GV (manufactured by Prime Polymers) '' and 30 parts by weight of the pellet, and 100 parts by weight of styrene-based elastomer `` Dynaron 1320P (manufactured by JSR) '' as a molding raw material B A mixture consisting of 20 parts by weight of the imparting agent "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) and 1 part by weight of the antioxidant" Irganox 1010 (manufactured by Chiba Specialty Chemicals) "was subjected to the T die method under the same conditions as in Example 1. It coextruded and produced the surface protection film.

As for the surface protection film, the thickness of the base material layer was 28 micrometers, the thickness of the intermediate | middle layer was 6 micrometers, and the thickness of the adhesion layer was 6 micrometers. Moreover, the thickness of the mold release layer of the surface protection film was 65 nm.

(Example 5)

A surface protective film was produced in the same manner as in Example 1 except that 3 parts by weight of methylenebisstearic acid amide "bisamide LA (manufactured by Nippon Chemical Co., Ltd.)" was used as the saturated fatty acid bisamide. As for the surface protection film, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesion layer was 6 micrometers. Moreover, the thickness of the mold release layer of a surface protection film was 40 nm.

(Example 6)

A surface protective film was produced in the same manner as in Example 1 except that 2.5 parts by weight of hexamethylenebisstearic acid amide "Srifax ZHS (manufactured by Nippon Chemical Co., Ltd.)" was used as the saturated fatty acid bisamide. As for the surface protection film, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesion layer was 6 micrometers. Moreover, the thickness of the release layer of a surface protection film was 15 nm.

(Example 7)

A surface protective film was produced in the same manner as in Example 1 except that 2.5 parts by weight of m-xylylenebisstearic acid amide "Srifax PXS (manufactured by Nippon Chemical Co., Ltd.)" was used as the saturated fatty acid bisamide. As for the surface protection film, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesion layer was 6 micrometers. Moreover, the thickness of the release layer of a surface protection film was 30 nm.

(Comparative Example 1)

A surface protective film was obtained in the same manner as in Example 1 except that no saturated fatty acid bisamide was used.

(Comparative Example 2)

A surface protective film was produced in the same manner as in Example 1 except that the amount of ethylenebisstearamide was changed to 0.5 part by weight. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.

(Comparative Example 3)

A surface protective film was produced in the same manner as in Example 1 except that the amount of ethylenebisstearamide was changed to 5 parts by weight. The thickness of the release layer of the surface protection film was 200 nm.

(Comparative Example 4)

A surface protective film was produced in the same manner as in Example 1 except that 3 parts by weight of stearic acid amide "Alflo S-10 (manufactured by Nichi Oil Company)" was used as the saturated fatty acid amide. A surface protective film was produced. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.

(Comparative Example 5)

A surface protective film was obtained in the same manner as in Example 1 except that instead of ethylenebisstearic acid amide, which is a saturated fatty acid bisamide, 3 parts by weight of oleic acid amide `` Acflo E-10 (manufactured by Nichi Oil) '', which was an unsaturated fatty acid amide, was used. Was produced. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.

(Comparative Example 6)

The surface protection was carried out in the same manner as in Example 1 except that instead of ethylenebisstearic acid amide, which is a saturated fatty acid bisamide, 3 parts by weight of ercaamide amide “Alflo P-10 (manufactured by Nichi Oil Co., Ltd.), which is an unsaturated fatty acid amide, was used. A film was produced. A surface protective film was produced. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.

(Comparative Example 7)

In the same manner as in Example 1, except that 3 parts by weight of ethylenebisoleic acid amide `` Alflo AD-281 (manufactured by Nichi Oil) '', which is an unsaturated fatty acid bisamide, was used instead of ethylenebisstearic acid amide, which is a saturated fatty acid bisamide. The surface protection film was produced. The thickness of the release layer of the surface protection film was 20 nm.

(evaluation)

The following items were evaluated about the obtained surface protection film of Examples 1-7 and Comparative Examples 1-7.

The results are shown in Table 1.

(1) development force

The surface protection films were wound around the core of 3 inches of internal diameters, respectively, and the roll of width 50mm was produced. In accordance with JIS Z0237, the surface protection film was rewound from a roll at a rewind speed of 20 m / min, and a high speed rewind force was measured. The measured value obtained is the developing force.

Good when the development force is 2 N / 50 mm or less (◎), good when it exceeds 2 N / 50 mm and 3.5 N / 50 mm or less (○), and when the development force exceeds 3.5 N / 50 mm ( X).

(Evaluation of time-lapse stability of development force)

Moreover, after having rolled the roll which is excellent evaluation or evaluation of favorable development in a 40 degreeC thermostat for 1 week, development force was measured and development force was evaluated by the same reference | standard. In addition, the comparative example 3 whose initial stage adhesive force is bad was not evaluated.

(2) presence or absence of floating, initial adhesive force and depth penetrated into the adhesive layer

A test piece was prepared by affixing a surface protective film having a width of 25 mm to a prism sheet composed of an acrylic resin having a thickness of 130 µm, having a prism of 50 µm and a height of 25 µm so as to cover the lens surface of the prism sheet. . Moreover, the surface protection film was affixed on the prism sheet at the speed | rate of 300 mm / min using 2 kg of compression rubber rollers at room temperature 23 degreeC, and 50% of a relative humidity. After leaving the test piece for 30 minutes in that state, the presence or absence of lifting was evaluated. It was evaluated that good (○) and excitation did not generate | occur | produce as a bad (x) that excitation did not arise.

Next, the initial adhesive force of the test piece in which the lifting did not generate | occur | produce was measured. In accordance with JIS Z0237, the surface protective film was peeled off at a rate of 300 mm / min, and the 180 degree peel strength was measured. The direction of peeling a surface protection film was made into the ridgeline direction of a prism. The obtained 180 degree peeling strength is initial stage adhesive force.

Moreover, as a result of observing the depth where the vertices of the prism ridge of the prism sheet penetrated with the adhesive by the scanning electron microscope (SEM), the depth which penetrated into the adhesive was 0.6 micrometer.

The case where the peeling strength (initial adhesive force) was 0.5 N / 25 mm or less was good (circle) and the case exceeding 0.5 N / 25 mm was evaluated as defect (x).

(3) sticking time-lapse adhesive force

The surface protection film of width 25mm was stuck so that the lens surface of a prism sheet might be covered. A prism sheet composed of an acrylic resin having a thickness of 130 μm and having a pitch of 50 μm and a height of 25 μm of the prism was used. The surface protection film was affixed at the speed | rate of 300 mm / min using 2 kg of compression rubber rollers in the environment of 23 degreeC of room temperature, and 50% of a relative humidity. After leaving for two weeks in an environment of room temperature at 23 ° C and a relative humidity of 50%, the surface protection film was peeled at a rate of 300 mm / min in accordance with JIS Z0237 to measure 180 ° peel strength. The direction of peeling a surface protection film was made into the ridgeline direction of a prism. The 180 degree peeling strength measured in this way was made into the sticking time-lapse adhesive force at 23 degreeC.

The case where peeling strength was 0.7 N / 25 mm or less was good (circle) and the case exceeding 0.7 N / 25 mm was evaluated as defect (x).

[result]

Note) The fatty acid amide types are as follows.

A: ethylenebisstearic acid amide

B: methylenebisstearic acid amide

C: Hexmethylenebisstearic acid amide

D: m-xylylenebisstearic acid amide

E: stearic acid amide

F: Oleamide

G: Ercasanamide

H: ethylenebisoleic acid amide

(Example 8)

As a molding material A, a mixture consisting of 100 parts by weight of polypropylene `` Y900GV (manufactured by Prime Polymer) '' and 3 parts by weight of ethylene bis stearic acid amide `` Alpha H50F (manufactured by Nichi Oil Company) '' which is a saturated fatty acid bisamide, and molding material B 100 parts by weight of a styrene elastomer "Dynaron 1320P (manufactured by JSR)", 15 parts by weight of a tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.)" as an tackifier, and "Irganox 1010 (Chiba Specialty) as an antioxidant. Chemicals Co., Ltd.) "1 part by weight was co-extruded by the T-die method under the following conditions to prepare a surface protective film. The surface protection film was 40 micrometers in thickness, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesive layer was 6 micrometers.

Moreover, the thickness of the release layer of a surface protection film was 49 nm.

<Condition>

Extrusion temperature: 200 ℃

Cast roll temperature: 25 ℃

(Example 9)

A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 20 parts by weight.

Moreover, the thickness of the release layer of a surface protection film was 50 nm.

(Example 10)

A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 25 parts by weight.

Moreover, the thickness of the mold release layer of the surface protection film was 48 nm.

(Example 11)

A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 30 parts by weight.

Moreover, the thickness of the mold release layer of a surface protection film was 53 nm.

(Example 12)

A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 35 parts by weight.

Moreover, the thickness of the mold release layer of a surface protection film was 55 nm.

(Example 13)

A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 40 parts by weight.

Moreover, the thickness of the mold release layer of the surface protection film was 48 nm.

(Example 14)

A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 45 parts by weight.

Moreover, the thickness of the release layer of a surface protection film was 52 nm.

(Comparative Example 8)

A surface protective film was obtained in the same manner as in Example 8 except that no saturated fatty acid bisamide was used.

(Comparative Example 9)

A surface protective film was obtained in the same manner as in Example 8 except that the saturated fatty acid bisamide was not used and the tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.) was 30 parts by weight.

(evaluation)

The following items were evaluated about the obtained surface protection film of Examples 8-14 and Comparative Examples 8-9.

The results are shown in Table 2.

(1) development force

The surface protection films were wound around the core of 3 inches of internal diameters, respectively, and the roll of width 50mm was produced. In accordance with JIS Z0237, the surface protection film was rewound from a roll at a rewind speed of 20 m / min, and a high speed rewind force was measured. The measured value obtained is the developing force.

Good when the development force is 2 N / 50 mm or less (◎), good when it exceeds 2 N / 50 mm and 3.5 N / 50 mm or less (○), and when the development force exceeds 3.5 N / 50 mm ( X).

(2) initial adhesion

It was affixed so that the lens surface of a prism sheet might be covered within 3 days after producing a surface protection film. As a prism sheet, what consists of acrylic resin of 130 micrometers in thickness, and prepared the thing of the pitch of the prism of 50 micrometers, and the height of 25 micrometers. The sticking conditions were affixed at a speed of 300 mm / min using a 2 kg compressed rubber roller under a room temperature of 23 ° C. and a relative humidity of 50%, and left in that state for 30 minutes, in accordance with JIS Z0237, 180 degree peeling strength in width 25mm was measured at the speed | rate of 300 mm / min. The peeling direction at this time was made into the ridgeline direction of a prism. The peeling strength measured in this way was made into initial stage adhesive force.

(3) 23 ° C. Time Lapse Adhesion

The adhesive force measured by the method similar to initial stage adhesive force was made into 23 degreeC sticking time lapse adhesive force except having left to stand for 1 week in 23 degreeC environment after sticking of a surface protection film.

[result]

As is clear from Table 2, the surface protective film which does not use saturated fatty acid bisamide has moderate adhesive force, but it is inferior in developing force despite the quantity of the tackifier suppressed. On the other hand, the surface protection film of this invention using the ethylene bis stearate amide which is saturated fatty acid bisamide, the moderate development force and the suitable initial stage adhesive force are acquired.

(Example 15)

As a molding material A, a mixture consisting of 100 parts by weight of polypropylene `` Y900GV (manufactured by Prime Polymer) '' and 3 parts by weight of ethylene bis stearic acid amide `` Alpha H50F (manufactured by Nichi Oil Company) '' which is a saturated fatty acid bisamide, and molding material B 100 parts by weight of a styrene elastomer "Dynaron 1320P (manufactured by JSR)", 20 parts by weight of a tackifier "Alcon P100 (manufactured by Arakawa Chemical Co., Ltd.)" as an tackifier, and "Irganox 1010 (Chiba Specialty) as an antioxidant. The thickness of the mixture consisting of 1 part by weight of the chemicals &quot; &quot; was co-extruded by the T-die method under the following conditions to produce a surface protective film. The surface protection film was 40 micrometers in thickness, the thickness of the base material layer was 34 micrometers, and the thickness of the adhesive layer was 6 micrometers.

Moreover, the thickness of the release layer of a surface protection film was 50 nm.

<Condition>

Extrusion temperature: 200 ℃

Cast roll temperature: 25 ℃

(Comparative Example 10)

A scroll of the surface protective film was obtained in the same manner as in Example 15 except that no saturated fatty acid bisamide was used.

(evaluation)

The following items were evaluated about each surface protection film obtained by making it above. The results are shown in Table 3.

(1) development force

The 50-mm-width roll of each surface protection film of an Example and a comparative example measured the high-speed rewinding force at the rewinding speed of 20 m / min, and made it the development force.

Good when the development force is 2 N / 50 mm or less (◎), good when it exceeds 2 N / 50 mm and 3.5 N / 50 mm or less (○), and when the development force exceeds 3.5 N / 50 mm ( X).

(2) adhesive force (room temperature)

What was cured for 1 week in the constant temperature layer of 23 degreeC after manufacture of the roll of a surface protection film was affixed on the lens surface and acryl plate of a prism sheet. The sticking conditions were carried out at 300 mm / min using a 2 kg compressed rubber roller under a room temperature of 23 ° C. and a relative humidity of 50%, and then left for 1 day in a 23 ° C. environment in accordance with JIS Z0237. , 180 degree peeling strength in width 25mm was measured at the speed | rate of 300 mm / min. The adhesive force measured in this way was made into lens surface adhesive force (normal temperature) and flat surface adhesive force (normal temperature), respectively.

(3) adhesive force (40 ℃)

The adhesive force measured by the method similar to adhesive force (room temperature) was made into lens surface adhesive force (40 degreeC), and flat surface adhesive force (40 degreeC), respectively, except the curing conditions of the roll of a surface protection film became 40 degreeC.

(4) temperature stability

The value which divided the adhesive force (40 degreeC) of each of a lens surface and a flat surface by adhesive force (room temperature) was made into the ratio of the decrease of adhesive force. The case where the reduction ratio was 70% or more was evaluated to be good stability (○) or less than 70% as poor stability (×).

[result]

As is apparent from Table 3, the surface protective film which does not use saturated fatty-acid bisamide is excellent in the temperature stability of adhesive force, but inferior in developing force. On the other hand, the surface protection film of this invention using ethylene bis stearate amide which is saturated fatty acid bisamide, when applied to the lens surface of a prism sheet, is excellent also in the temperature stability of adhesive force, and development force.

Industrial availability

The surface protection film of this invention can be used for protection of the lens surface of a prism sheet.

Claims (8)

Molding raw material A containing a saturated fatty acid bisamide and a polyolefin resin, and
Produced by co-extrusion of the molding raw material B containing a styrene-based elastomer,
(A) A release layer mainly composed of saturated fatty acid bisamides having a thickness of 1 to 100 nm,
(B) a polyolefin resin layer as a substrate layer, and
(C) The surface protection film for prism sheets with which the styrene-type elastomer layer as an adhesive layer was laminated | stacked. The method of claim 1,
The surface protection film for prism sheets whose said molding raw material A contains 1-4 weight part of saturated fatty acid bisamide with respect to 100 weight part of polyolefin resins. The method according to claim 1 or 2,
The surface protection film for prism sheets whose saturated fatty acid bisamide is ethylene bis stearic acid amide, methylene bis stearic acid amide, or hexamethylene bis stearic acid amide. The method according to claim 1 or 2,
Surface protection film for prism sheets whose saturated fatty acid bisamide is saturated fatty acid aromatic bisamide. The method according to any one of claims 1 to 4,
The surface protection film for prism sheets which has an intermediate layer between the said base material layer and the said adhesive layer. The method of claim 5, wherein
The surface protection film for prism sheets whose said intermediate layer is a mixture of polyolefin resin and styrene elastomer containing saturated fatty acid bisamide. (A) Mold release layer of thickness 1-100 nm which mainly consists of saturated fatty-acid bisamide,
(B) a polyolefin resin layer serving as a base material layer,
(C) As a manufacturing method of the surface protection film for prism sheets which the styrene-type elastomer layer used as an adhesive layer was laminated | stacked in this order,
The manufacturing method of the surface protection film for prism sheets which co-extrudes the shaping | molding raw material A containing 1-4 weight part of saturated fatty acid bisamide, and the shaping | molding raw material B containing styrene-type elastomer with respect to 100 weight part of polyolefin resin. A prism sheet having a plurality of triangular prism prisms on a lens surface, and
A release layer mainly composed of (A) saturated fatty acid bisamide affixed to the lens surface, a release layer having a thickness of 1 to 100 nm, (B) a polyolefin resin layer as a base material layer, and
(C) the surface protection film for prism sheets in which the styrene-type elastomer layer as an adhesive layer was laminated | stacked,
A prism sheet having a surface protection film affixed to the pressure-sensitive adhesive layer of the prism having a depth of 0.3 µm or more.