JP2000162437A - Polarizing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To repeatedly allow adhesion/removal to/from an optical part having a smooth surface and to easily peel a polarizing sheet itself and an attached body without causing any damage or contamination by arranging a specific polyurethane elastomer layer as an adhering layer. SOLUTION: A polyurethane elastomer layer serving as an adhering layer is arranged on at least one face of a polarizing film. In the polyurethane elastomer layer, 100% modulus ranges 20-60 kg/cm2. Desirably, it ranges 25-50 kg/cm2, and a range of 25-40 kg/cm2 is particularly preferable. As the polyurethane elastomer, a siloxane-degenerated polyurethane elastomer is desirable. The siloxane-degenerated polyurethane elastomer contains 2-40 wt.% of polysiloxane constituent desirably, and its content of 2-30 wt.% is more preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be applied to optical parts such as a liquid crystal cell of a liquid crystal display device to damage an adherend.
The present invention relates to a polarizing sheet that can be easily peeled off without being contaminated and that can be repeatedly attached.

[0002]

2. Description of the Related Art A polarizing film is attached to an optical component such as a liquid crystal cell of a liquid crystal display device. To attach the polarizing film, an adhesive layer for attaching to a liquid crystal cell or the like is formed on one side of the polarizing film, and a release film is attached on the surface of the adhesive layer. On the other side of the polarizing film, a protective film is attached. To attach the polarizing film, specifically, the release film of the polarizing film is peeled off, the polarizing film is attached to an optical component such as a liquid crystal cell by the exposed adhesive layer, and then the protective film on the surface of the polarizing film is peeled off. It is performed according to the following procedure. Most polarizing film substrates used for optical components such as liquid crystal cells have a configuration in which a polyvinyl alcohol (PVA) -based polarizer is sandwiched by a triacetyl cellulose (TAC) -based protective film, and therefore have poor dimensional stability. In particular, under heat or wet heat conditions, dimensional changes and curls due to expansion and contraction are large. When such a polarizing film is adhered to an optical component such as a liquid crystal cell with an adhesive, problems such as foaming or peeling off the adhesive layer tend to occur. In particular, under wet heat conditions, water enters the interface between the pressure-sensitive adhesive layer and the glass, and is easily peeled off. Traditionally, people have been too conscious of preventing these problems,
The adhesive used had high adhesive strength. As a result, the adhesive strength of the pressure-sensitive adhesive increased over a short period of time after application, and it was difficult to re-apply due to damage or the like. Also, when re-attaching, damage to the adherend such as a change in the cell gap of the liquid crystal cell,
Also, there is a problem of adherend contamination such as adhesive residue.

[0003]

SUMMARY OF THE INVENTION The present invention is capable of repeatedly attaching and detaching an optical component having a smooth surface such as a liquid crystal cell, and easily and without damaging or contaminating the polarizing sheet itself and the adherend. An object is to provide a polarizing sheet that can be peeled off.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a polyurethane elastomer layer having a 100% modulus of 20 to 60 kg / cm ² is provided as an adhesive layer. Thereby, it is possible to adhere to an optical component having a smooth surface, and to easily peel off without damaging or contaminating the polarizing sheet itself and the adherend, and to be able to repeatedly stick and peel. The present inventors have found and completed the present invention based on this finding.

That is, the present invention provides a polarizing film having a 100% modulus of 20 to 100% as an adhesive layer on at least one side of the polarizing film.
A polarizing sheet provided with a polyurethane elastomer layer of 60 kg / cm ² .

Further, the present invention provides a polarizing sheet wherein the polyurethane elastomer in the polarizing sheet is a siloxane-modified polyurethane elastomer. The present invention also provides a polarizing sheet, wherein the siloxane-modified polyurethane elastomer in the above polarizing sheet contains 2 to 40% by weight of a polysiloxane component. Hereinafter, the present invention will be described in detail.

The polarizing film in the polarizing sheet of the present invention is not particularly limited as long as it functions as a polarizing film. Examples of the polarizing film include a narrowly defined polarizing film and an elliptically polarizing film. Specific examples of the elliptically polarizing film include a polarizing film in which a retardation film is laminated on one surface. A typical example of a polarizing film is a polarizing film in which a polyvinyl alcohol layer is sandwiched between two polyacetyl cellulose layers. A typical example of an elliptically polarizing film is a polyvinyl alcohol layer between two polyacetyl cellulose layers. An elliptically polarizing film in which a retardation film is further laminated on a polarizing film having layers interposed therebetween is exemplified. Examples of the retardation film include a uniaxially stretched polycarbonate film and a polysulfone film.

In the polarizing sheet of the present invention, at least one side of the polarizing film has a 100% modulus of 20 to 6
A polyurethane elastomer layer of 0 kg / cm ² is provided. In the case of a polyurethane elastomer having a 100% modulus of less than 20 kg / cm ² , the adhesive force to an adherend is large, and particularly, the adhesive force is significantly increased over time, and peeling is difficult. In some cases, the adherend may be damaged or contaminated when peeled off. Conversely 100
The polyurethane elastomer layer having a% modulus of more than 60 kg / cm ² has too small an adhesive force to an adherend,
Cannot be pasted.

[0009] 100% modulus is 20-60 kg / c
polarizing the polyurethane elastomer layer is used as the cement layer is m ² sheet has a moderate sticking property against smooth adherend surface and damage the polarizing sheet itself and the adherend, easily without contaminating It could be peeled off and could be used repeatedly. The term "adhesiveness" as used herein means that the polarizing sheet is held on the adherend, and that the polarizing sheet itself and the adherend can be easily peeled off without being damaged, and can be used repeatedly. The property is that the adhesive force is 10 to 300 g / 25 mm. The 100% modulus of the polyurethane elastomer layer is between 20 and
The range is 60 kg / cm ² , but the preferred range is 25 kg / cm ^2.
In the range of to 50 kg / cm ^2, particularly preferred range is from 25~40kg / cm ^2.

[0010] The weight average molecular weight of the polyurethane elastomer is preferably in the range of 50,000 to 300,000, and particularly preferably in the range of 60,000 to 200,000. Examples of the polyurethane elastomer include a polyurethane elastomer and a modified polyurethane elastomer. As the modified polyurethane elastomer, a siloxane-modified polyurethane elastomer is preferable.

The polyurethane elastomer is composed of a soft segment composed mainly of a polymer polyol, a hard segment composed of a polyisocyanate such as diisocyanate and a chain extender. As the type of polyurethane elastomer, a thermoplastic polyurethane elastomer obtained by polymerizing a polymer polyol and a polyisocyanate such as diisocyanate such as tolylene diisocyanate (TDI) and 4,4′-diphenylmethane diisocyanate (MDI) is mixed with an organic solvent. A diluted one-part type or a two-part type in which a polyisocyanate is further added and cured before application in a separate system may be used. In addition, a moisture-curable or hot-melt extrusion-type hot-melt polyurethane elastomer which reacts isocyanate with moisture in the air may be used.

As the polymer polyol, known polymer polyols can be used, but the weight average molecular weight is from 600 to 10,000.
00 is preferable, and particularly preferably 1,000 to 4,000. Examples of the polymer polyol include a polyester polyol, a polyether polyol, a polycarbonate polyol, and a polylactone polyol, and a polyester polyol and a polyether polyol are particularly preferable. When a polyurethane elastomer obtained by reacting a high molecular weight polyol which is a polyether polyol with at least 50% by weight of the polyurethane elastomer and a polyisocyanate is used, the adherence of the adherend is improved and the adherend is easily peeled off. It also becomes easier.

Further, the above polyether polyol is
This is a mixture of (A) a polyether polyol comprising a linear alkylene group having 4 to 8 carbon atoms and (B) a polyether polyol comprising an alkylene group having 2 to 3 carbon atoms and / or an alkylene group having a side chain. It is preferable that the mixing ratio can be appropriately selected depending on the application.
The range of / 90 to 90/10 is preferred. Examples of the linear alkylene group having 4 to 8 carbon atoms of (A) include a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, and an octamethylene group. As the polyether polyol (A) composed of a linear alkylene group having 4 to 8 carbon atoms, polytetramethylene glycol is typical. Examples of the alkylene group having 2 to 3 carbon atoms in (B) include an ethylene group and a propylene group. As the alkylene group having a side chain, those having 2 to 8 carbon atoms in the main chain are preferable, and the side chain has 1 to 1 carbon atoms.
An alkyl group of 4 is preferred. Typical examples of the polyether polyol (B) include polyethylene glycol, polypropylene glycol, and ethylene glycol / propylene glycol copolymer.

In the present invention, a low molecular weight diol, an aromatic diamine, or the like can be used as a chain extender together with the above polymer polyol as a component of the polyurethane elastomer. Low molecular diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3
-Butanediol, 1,6-hexanediol, diethylene glycol, cyclohexanediol and the like,
Examples of the aromatic diamine include isophorone diamine, linear aliphatic diamine, and m-phenylenediamine. As the polyisocyanate, a known polyisocyanate can be used. As a specific example, for example,
4,4'-diphenylmethane diisocyanate (MD
I), hydrogenated MDI, tolylene diisocyanate (TD)
I), isophorone diisocyanate (IPDI) and the like are typical.

The siloxane-modified polyurethane elastomer is obtained by modifying a polyurethane elastomer with a polysiloxane, and preferably contains 2 to 40% by weight, more preferably 2 to 30% by weight of a polysiloxane component. When the polysiloxane component is less than 2% by weight, when applied to an adherend made of a polycarbonate resin, an acrylic resin, or the like, the sticking force becomes too large as the sticking time becomes longer, and it cannot be easily peeled off. is there. On the other hand, when the content of the polysiloxane component exceeds 40% by weight, the sticking property may be significantly reduced. That is, the polysiloxane component can be attached to any of the adherends made of glass, polycarbonate resin, acrylic resin, and the like.
% By weight.

A preferred method of obtaining a siloxane-modified polyurethane elastomer is, for example, a method of reacting a polysiloxane having an active hydrogen group, a high molecular polyol, and a polyisocyanate. And a method in which a siloxane-modified polyurethane elastomer intermediate obtained by reacting a polysiloxane, a polymer polyol and a polyisocyanate having the same is further crosslinked by further mixing a curing agent. The siloxane-modified polyurethane elastomer intermediate usually has a weight average molecular weight of 5,000 to 300,000. The average molecular weight of the polysiloxane having an active hydrogen group is preferably from 600 to 10,000, and the number of active hydrogen groups in the molecule may be one or more, but is preferably two or more. Representative specific examples of preferred polysiloxanes having an active hydrogen group include those having the following structural formula.

[0017]

Embedded image

In the above structural formulas (1) to (5), R is an alkylene group having 2 to 8 carbon atoms, R ₁ and R ₂ are each an alkylene group having 1 to 4 carbon atoms, and n and m are Each is an integer of 1 or more. In preparing the siloxane-modified polyurethane elastomer, a curing agent may not be used. However, it is more preferable to prepare a siloxane-modified polyurethane elastomer intermediate and mix the curing agent with the intermediate. Typical examples of the curing agent include polyisocyanate, a polyisocyanate prepolymer obtained from a polyhydric alcohol and a polyisocyanate, a polyisocyanate prepolymer obtained from a polyol and a polyisocyanate, and a block copolymer thereof.
When a curing agent is used, its amount is 1 to 100 parts by weight of the solid content of the siloxane-modified polyurethane elastomer.
0 to 70 parts by weight is preferred.

If necessary, if the 100% modulus value is within the above range, a filler such as an organic powder or an inorganic powder, a plasticizer such as an aromatic ester or a chlorinated paraffin, a UV absorber or the like may be added to the polyurethane elastomer. Agents, antioxidants, coloring agents, etc., or other resins obtained by adding or copolymerizing a polyurethane elastomer with another resin such as a poly (meth) acrylic resin, a polyester resin, or a polyamide resin. Is also good. The addition amount or copolymerization amount of the other resin is preferably 20% by weight or less. Conventionally,
In general, adhesives are used for sticking sheets such as seals and labels, and it is difficult to adjust tack and adhesive strength with adhesives using this adhesive. In many cases, peeling is difficult, and repeated use is difficult. However, the polarizing sheet of the present invention is different from the above, in that the function intended by the present invention is obtained by the self-adhesive force of the siloxane-modified polyurethane elastomer itself.

The polarizing sheet of the present invention has at least one polyurethane elastomer layer, and may have two or more polyurethane elastomer layers. The layer thickness of the polyurethane elastomer layer comprising at least one layer is usually at least 10
The thickness may be set to at least μm, preferably 20 to 100 μm. If the thickness is less than 10 μm, the adhering force to the adherend may be insufficient, or bubbles may be trapped between the adherend and the polarizing sheet, resulting in insufficient adherence. If the polyurethane elastomer layer has a thickness of 100 μm or more, the function of the present invention is not impaired, but it is not economical to make the polyurethane elastomer layer thicker than necessary.

In the polarizing sheet of the present invention, for example, first, a 100% modulus value of 20 to 6 is applied to the release-treated surface of the release film.
A polyurethane elastomer in a range of 0 kg / cm ² is applied by a conventionally known coating method, for example, a knife coat, a blade coat, a die coat, a roll coat, a bar coat, and the like, and after the polyurethane elastomer is sufficiently dried, a transfer method is used. It is preferably manufactured by forming at least one polyurethane elastomer layer on a polarizing film serving as a support. When the transfer method is used, the polyurethane elastomer layer can be formed on the surface of the polarizing film without swelling the triacetyl cellulose constituting the polarizing film. Generally, a polarizing film having a thickness of 50 to 300 μm is used. When the polyurethane elastomer layer is provided on both sides of the polarizing film, a double-sided polarizing sheet or roll can be obtained. The polarizing film may be subjected to a conventionally known adhesion enhancing treatment, for example, a saponification treatment, a corona discharge treatment, or another anchor coating treatment, for the purpose of improving the adhesion to the polyurethane elastomer layer.

Further, the polarizing sheet of the present invention may be provided with a protective sheet for protecting the surface of the polarizing film. As the protective sheet, for example, a conventionally known protective sheet having high smoothness may be used. As such a protective sheet, a polyethylene film or a polyethylene terephthalate film provided with an ethylene-vinyl acetate resin layer or an acrylic pressure-sensitive adhesive layer on one surface is used.

In the case of the elliptically polarizing film, the polarizing film and the retardation film are preferably laminated via a pressure-sensitive adhesive layer. As the pressure-sensitive adhesive layer, a general one can be used. It is preferable to use the polyurethane elastomer layer used in the above. When the polyurethane elastomer layer is used, it is possible to suppress a polarization hindrance that the peripheral portion of the polarizing film is whitened. In addition,
The adhesive force of the pressure-sensitive adhesive layer is preferably 10 g / 25 mm or more stronger than that of the adhesive layer for attaching the polarizing film to the adherend.

[0024]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by these examples. Various evaluation tests in the examples were performed by the following methods. (1) 100% modulus value Polyurethane elastomer blended solution is mixed with polyethylene terephthalate release film (manufactured by Lintec Corporation)
And heated at 100 ° C. for 5 minutes to a thickness of 40 μm, and further placed in a 23 ° C. × 65% RH atmosphere.
After standing for a week, pulling speed 300m with universal tensile tester
m / min, stress at a specimen width of 5 mm and a tensile interval of 20 mm
Measure the elongation curve and calculate the stress value at which the elongation becomes 100% in kg.
/ Cm ² unit to obtain a 100% modulus value.

(2) Adhesive force A polarizing sheet was applied to the following adherend at 23 ° C. × 65% RH.
In an atmosphere, a 2 kg roller is reciprocated once and pressed and
After 4 hours, the adhesive force was measured. Using a universal tensile tester, crosshead speed 300 mm / min, surface substrate side 18
The film was peeled at 0 ° and the adhesive force was measured. Glass plate (manufactured by Nippon Sheet Glass Co., Ltd., trade name: H-coated glass) Acrylic plate (manufactured by Nippon Test Panel Industry Co., Ltd., trade name:
Acrylite 001) Polycarbonate plate (PC plate) (trade name: Iupilon NF-2000, manufactured by Nippon Test Panel Industry Co., Ltd.)

(3) Adherability The adhesive force after 24 hours was 1 for all of the above adherends.
A sample having a quality of 0 to 300 g / 25 mm was evaluated as ○, and the others were evaluated as x. (4) Repeatability After all of the above adherends were repeatedly adhered 10 times, those that could be adhered again were marked with ○, and those that could not be adhered were marked with x. (5) Contamination of the adherend The surface of the adherend after the measurement of the adhesive force was visually observed. If the adherend had no fogging and a part of the polarizing sheet had not been transferred, it was evaluated as good (○). Was evaluated as x.

Example 1 Polytetramethylene glycol (weight average molecular weight: 20
00) and 10 parts by weight of a chain extender 1,4-butanediol were added to dimethyl sulfoxide (DMF).
171 parts by weight, tolylene diisocyanate 30
The mixture was reacted at 80 ° C. for 8 hours to obtain a viscous solution having a solid content of 45% by weight and a viscosity of 1,000 poise (25 ° C.). The weight average molecular weight of the solid polyurethane resin intermediate was about 100,000. This polyurethane resin intermediate 31
One part by weight of 30 parts by weight of coronate HL (manufactured by Nippon Polyurethane Co., Ltd.) which is an aliphatic polyisocyanate as a curing agent is added to a 38 μm-thick polyethylene terephthalate release film (manufactured by Lintec Corporation).
And heated at 100 ° C. for 5 minutes to form a polyurethane elastomer layer having a thickness of 40 μm, transferred to a polarizing film (commercial product, 180 μm thick product), and further heated to 23 ° C. × 65% RH atmosphere. The sheet was left for one week to prepare a polarizing sheet. As a result of examining the adhesive strength of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, all were good.

Example 2 Coronate H which is an aliphatic polyisocyanate as a curing agent was added to 311 parts by weight of the polyurethane resin intermediate of Example 1.
L (manufactured by Nippon Polyurethane) was applied to the release-treated surface of a 38 μm-thick polyethylene terephthalate release film (manufactured by Lintec Corporation) in the same manner as in Example 1 except that 35 parts by weight of L (manufactured by Nippon Polyurethane) was added. Heated for 40 minutes to form a polyurethane elastomer layer having a thickness of 40 μm, which was transferred to a polarizing film (commercially available, 180 μm thick),
Furthermore, it is left for one week in an atmosphere of 23 ° C. and 65% RH,
A polarizing sheet was produced. As a result of examining the adhesive strength of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, all were good.

Example 3 4 parts by weight of polysiloxane having the structural formula (2) having a weight average molecular weight of 1600 and polytetramethylene glycol (weight average molecular weight: 200) as a polyol
0) and 100 parts by weight of a chain extender 1,4-butanediol were dissolved in 176 parts by weight of DMF, 30 parts by weight of tolylene diisocyanate was added, and the mixture was reacted at 80 ° C. for 8 hours. Weight%, viscosity 900 poise (25
C). The weight average molecular weight of the solid siloxane-modified polyurethane resin intermediate was about 80,000.
To a 320 part by weight of this siloxane-modified polyurethane resin intermediate, 30 parts by weight of a coronate HL (manufactured by Nippon Polyurethane Co., Ltd.) which is an aliphatic polyisocyanate as a curing agent was added, and a 38 μm-thick polyethylene terephthalate release film (Lintech Co. (Manufactured by the company) and heated at 100 ° C for 5 minutes to a thickness of 40μ.
m siloxane-modified polyurethane elastomer layer,
This was transferred to a polarizing film (commercially available product, 180 μm thick product), and left in a 23 ° C. × 65% RH atmosphere for one week to prepare a polarizing sheet. As a result of examining the adhesive strength of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, all were good.

Example 4 Intermediate 32 of the siloxane-modified polyurethane resin of Example 3
38 μm in thickness in the same manner as in Example 3 except that coronate HL (manufactured by Nippon Polyurethane), which is an aliphatic polyisocyanate, was added as a curing agent to 0 part by weight.
Of polyethylene terephthalate release film (manufactured by Lintec Co., Ltd.) and heated at 100 ° C. for 5 minutes to form a 40 μm-thick siloxane-modified polyurethane elastomer layer. This is a polarizing film (commercial product, 180 μm-thick product) ) And further transferred to 23 ° C x 65%
It was left in an RH atmosphere for one week to produce a polarizing sheet. As a result of examining the adhesive strength of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, all were good.

Example 5 A polysiloxane having the structural formula (5) having a weight average molecular weight of 6000 was 80 parts by weight, and a polytetramethylene glycol (weight average molecular weight: 200) was used as a polyol.
0), 50 parts by weight of polypropylene glycol (weight average molecular weight: 2,000), 1,4-chain extender
10 parts by weight of butanediol was dissolved in 281 parts by weight of DMF, and 40 parts by weight of tolylene diisocyanate was added.
Reaction at 80 ° C. for 8 hours, solid content 45% by weight, viscosity 12
A viscous solution of 00 poise (25 ° C.) was obtained. The weight average molecular weight of the solid siloxane-modified polyurethane resin intermediate was about 200,000. 60 parts by weight of coronate HL (manufactured by Nippon Polyurethane), which is an aliphatic polyisocyanate as a curing agent, was added to 511 parts by weight of this siloxane-modified polyurethane resin intermediate, and a 38 μm-thick polyethylene terephthalate release film (Rintech Co., Ltd.) Co., Ltd.) and heated at 100 ° C. for 5 minutes to form a siloxane-modified polyurethane elastomer layer having a thickness of 40 μm.
(Thickness of 0 μm) and left in a 23 ° C. × 65% RH atmosphere for one week to produce a polarizing sheet. As a result of examining the adhesive strength of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, all were good.

Example 6 The siloxane-modified polyurethane resin intermediate 51 of Example 5
38 μm in thickness in the same manner as in Example 5 except that 80 parts by weight of Coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is an aliphatic polyisocyanate, was added as a curing agent to 1 part by weight.
Of polyethylene terephthalate release film (manufactured by Lintec Co., Ltd.) and heated at 100 ° C. for 5 minutes to form a 40 μm-thick siloxane-modified polyurethane elastomer layer. This is a polarizing film (commercial product, 180 μm-thick product) ) And further transferred to 23 ° C x 65%
It was left in an RH atmosphere for one week to produce a polarizing sheet. As a result of examining the adhesive strength of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, all were good.

Comparative Example 1 Coronate H which is an aliphatic polyisocyanate as a curing agent was added to 311 parts by weight of the polyurethane resin intermediate of Example 1.
L (manufactured by Nippon Polyurethane) was applied to the release-treated surface of a 38 μm-thick polyethylene terephthalate release film (manufactured by Lintec Corporation) in the same manner as in Example 1 except that 10 parts by weight of L (manufactured by Nippon Polyurethane) was added. Heated for 40 minutes to form a polyurethane elastomer layer having a thickness of 40 μm, which was transferred to a polarizing film (commercially available, 180 μm thick),
Furthermore, it is left for one week in an atmosphere of 23 ° C. and 65% RH,
A polarizing sheet was produced. The adhesive strength of the polarizing sheet to the adherend, such as a glass plate, an acrylic plate, and a PC plate, and the contamination of the adherend were good, but the adhesive force was too high to be easily peeled off and could not be used repeatedly. .

Comparative Example 2 Siloxane-Modified Polyurethane Resin Intermediate 32 of Example 3
38 μm in thickness in the same manner as in Example 3 except that 50 parts by weight of coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is an aliphatic polyisocyanate, was added as a curing agent to 0 parts by weight.
Of polyethylene terephthalate release film (manufactured by Lintec Co., Ltd.) and heated at 100 ° C. for 5 minutes to form a 40 μm-thick siloxane-modified polyurethane elastomer layer. This is a polarizing film (commercial product, 180 μm-thick product) ) And further transferred to 23 ° C x 65%
It was left in an RH atmosphere for one week to produce a polarizing sheet. As a result of examining the adhesion of the polarizing sheet to a glass plate, an acrylic plate, and a PC plate as adherends, contamination of the adherend, and repetitive use, the adherence was too low to obtain good adherence. Was.

Comparative Example 3 Siloxane-Modified Polyurethane Resin Intermediate 51 of Example 5
38 μm in thickness in the same manner as in Example 5 except that 10 parts by weight of coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is an aliphatic polyisocyanate, was added as a curing agent to 1 part by weight.
Coated on a release-treated surface of a polyethylene terephthalate release film (manufactured by Lintec Corporation) and heated at 100 ° C. for 5 minutes to form a 40 μm-thick siloxane-modified polyurethane elastomer layer. This is a polarizing film (commercial product, 180 μm-thick product) ) And further transferred to 23 ° C x 65%
It was left in an RH atmosphere for one week to produce a polarizing sheet. The adhesive strength of the polarizing sheet to the adherend, such as a glass plate, an acrylic plate, and a PC plate, and the contamination of the adherend were good, but the adhesive force was too high to be easily peeled off and could not be used repeatedly. . 10 of Examples 1 to 6 and Comparative Examples 1 to 3
Table 1 shows the 0% modulus value and the evaluation results.

[0036]

[Table 1]

Example 7 Example 7 was carried out in the same manner as in Example 2 except that the following elliptically polarizing film was used instead of the polarizing film. The sticking layer was provided on the retardation film surface of the elliptically polarizing film. The 100% modulus value and the sticking force of the polyurethane elastomer layer as the sticking layer were the same as in Example 2. This polarizing sheet has no polarization hindrance such as whitening,
It was excellent in stickability to an adherend, repetitive use, and contamination of an adherend.

Elliptically polarizing film: Coronate HL which is an aliphatic polyisocyanate as a curing agent was added to 320 parts by weight of the siloxane-modified polyurethane resin intermediate of Example 3.
A film obtained by adding 20 parts by weight (manufactured by Nippon Polyurethane Co.) was applied to the release-treated surface of a 38 μm-thick polyethylene terephthalate release film (manufactured by Lintec Corporation), and heated at 100 ° C. for 5 minutes to obtain a 40 μm-thick film. Polyurethane elastomer layer (100% modulus value: 35k
g / cm ² ) and a polarizing film (commercial product, 18
(Thickness of 0 μm), and a phase difference film of a uniaxially stretched polycarbonate film (50 μm thickness) was laminated and adhered to the surface of the film from which the polyethylene terephthalate release film had been removed (sticking force: 130 g / 2).
5 mm (to PC board)).

Example 8 Example 8 was carried out in the same manner as in Example 6, except that the following elliptically polarizing film was used instead of the polarizing film. The sticking layer was provided on the retardation film surface of the elliptically polarizing film. The 100% modulus value and the sticking force of the polyurethane elastomer layer as the sticking layer were the same as those in Example 6. This polarizing sheet has no polarization hindrance such as whitening,
It was excellent in stickability to an adherend, repetitive use, and contamination of an adherend.

Elliptically polarizing film: 320 parts by weight of the siloxane-modified polyurethane resin intermediate of Example 3 and coronate HL which is an aliphatic polyisocyanate as a curing agent
A film obtained by adding 20 parts by weight (manufactured by Nippon Polyurethane Co.) was applied to the release-treated surface of a 38 μm-thick polyethylene terephthalate release film (manufactured by Lintec Corporation), and heated at 100 ° C. for 5 minutes to obtain a 40 μm-thick film. Polyurethane elastomer layer (100% modulus value: 35k
g / cm ² ) and a polarizing film (commercial product, 18
(Thickness of 0 μm), and a phase difference film of a uniaxially stretched polycarbonate film (50 μm thickness) was laminated and adhered to the surface of the film from which the polyethylene terephthalate release film had been removed (sticking force: 130 g / 2).
5 mm (to PC board)).

[0041]

The polarizing sheet of the present invention can be repeatedly attached to and detached from an adherend of an optical component such as a liquid crystal cell, and can be easily formed without damaging or contaminating the polarizing sheet itself and the adherend. Can be peeled. Therefore, the polarizing sheet of the present invention is extremely useful in practical use.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomo Shibano 19-22 F-22 Term Tonoyamacho, Higashimatsuyama City, Saitama Prefecture (Reference) 2H049 BA02 BB24 BB54 4F100 AG00 AK25 AK42 AK45 AK51B AK52B AL08B AL09B BA02 EC04 EH46 GB41 JK07B JL10 JLJ YY00B

Claims (3)

[Claims] 1. A polarizing sheet comprising a polarizing film and a polyurethane elastomer layer having a 100% modulus of 20 to 60 kg / cm ² provided as an adhesive layer on at least one surface of the polarizing film. 2. The polarizing sheet according to claim 1, wherein the polyurethane elastomer is a siloxane-modified polyurethane elastomer. 3. The polarizing sheet according to claim 2, wherein the siloxane-modified polyurethane elastomer contains 2 to 40% by weight of a polysiloxane component.