TWI795379B - Polarizing film and method for producing polarizing laminzted film - Google Patents

Polarizing film and method for producing polarizing laminzted film Download PDF

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TWI795379B
TWI795379B TW106141161A TW106141161A TWI795379B TW I795379 B TWI795379 B TW I795379B TW 106141161 A TW106141161 A TW 106141161A TW 106141161 A TW106141161 A TW 106141161A TW I795379 B TWI795379 B TW I795379B
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film
polarizing
layer
laminated film
polyvinyl alcohol
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TW201830063A (en
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日商住友化學股份有限公司
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00Ancillary operations in connection with laminating processes
    • B32B38/0012Mechanical treatment, e.g. roughening, deforming, stretching
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00Ancillary operations in connection with laminating processes
    • B32B38/14Printing or colouring
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14Protective coatings, e.g. hard coatings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00Ancillary operations in connection with laminating processes
    • B32B38/0012Mechanical treatment, e.g. roughening, deforming, stretching
    • B32B2038/0028Stretching, elongating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00Ancillary operations in connection with laminating processes
    • B32B2038/0052Other operations not otherwise provided for
    • B32B2038/0076Curing, vulcanising, cross-linking

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Polarising Elements (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)

Abstract

The present invention provides a polarizing film having high optical characteristics while suppressing contraction force, and a method for producing a polarizing laminated film. In the polarizing film, iodine is oriented in a polyvinyl alcohol-based resin layer. The polarizing film has a boron content of 2.5 wt% or more and 4.1 wt% or less; a visibility correction monoaxial transmittance (Ty) of more than 40.5%; the ratio represented by a parallel absorbance/orthogonal absorbance at a wavelength of 475 nm is less than 0.022.

Description

偏光膜及偏光性積層膜之製造方法 Polarizing film and method for producing polarizing laminated film

本發明係關於偏光膜及偏光性積層膜之製造方法。 The present invention relates to a method for manufacturing a polarizing film and a polarizing laminated film.

偏光板,被廣泛使用於液晶顯示裝置等的顯示裝置等。偏光板,一般係由聚乙烯醇系樹脂所構成的偏光片層的單面或兩面貼合保護膜所構成者。伴隨影像顯示裝置的移動式機器、薄型電視等的展開,對偏光板的薄型化的要求變高。 Polarizing plates are widely used in display devices such as liquid crystal display devices and the like. A polarizing plate is generally composed of a polarizer layer made of polyvinyl alcohol-based resin and a protective film attached to one or both sides. With the development of mobile devices such as image display devices and thin TVs, there is an increasing demand for thinner polarizing plates.

作為製造具有薄膜的偏光片層的偏光板的方法,已知在基材膜上藉由塗佈含有聚乙烯醇系樹脂的塗佈液,形成聚乙烯醇系樹脂層之積層膜,延伸積層膜後,施行於聚乙烯醇系樹脂層吸附二色性色素之染色處理,製造基材膜上形成有偏光片層的偏光性積層膜的方法(例如專利文獻1)。 As a method of producing a polarizing plate having a thin-film polarizer layer, it is known to apply a coating solution containing a polyvinyl alcohol-based resin on a base film to form a laminated film of a polyvinyl alcohol-based resin layer, and to stretch the laminated film. Thereafter, a dyeing treatment in which a dichroic dye is adsorbed on a polyvinyl alcohol-based resin layer is performed to produce a polarizing laminated film in which a polarizer layer is formed on a base film (for example, Patent Document 1).

根據上述方法,因藉由塗佈形成聚乙烯醇系樹脂層,相較於由聚乙烯醇系樹脂所構成的單層(單體)膜的薄膜化,聚乙烯醇系樹脂層容易薄膜化,所以偏光片 層的薄膜化也變容易。 According to the above-mentioned method, since the polyvinyl alcohol-based resin layer is formed by coating, the polyvinyl alcohol-based resin layer is easily thinned compared to thinning of a single-layer (monomeric) film composed of the polyvinyl alcohol-based resin, Therefore, thinning of the polarizer layer becomes easy.

於專利文獻1中記載為了得到良好的光學特性而高倍率延伸。 Patent Document 1 describes high-magnification stretching in order to obtain good optical characteristics.

另一方面,不是如上述的在基材膜上塗佈含有聚乙烯醇系樹脂的塗佈液的方法所製造者,專利文獻2中記載一種為了抑制滲出的發生而提高硼酸交聯度的偏光片。 On the other hand, it is not a manufacturer of the above-mentioned method of coating a coating liquid containing a polyvinyl alcohol-based resin on a base film, and Patent Document 2 describes a polarizer that increases the degree of boric acid crosslinking in order to suppress the occurrence of bleeding. piece.

[先前技術文獻] [Prior Art Literature] [專利文獻] [Patent Document]

[專利文獻1]日本專利第5667016號公報 [Patent Document 1] Japanese Patent No. 5667016

[專利文獻2]日本專利第5985813號公報 [Patent Document 2] Japanese Patent No. 5985813

為了提高偏光片層、偏光片的偏光度,如上述,除了提高延伸倍率、提高硼酸交聯度外,考慮提高頸縮率等。但是,於該等的方法,加熱偏光片層或偏光片時的收縮力有變大的傾向,變得容易發生偏光片層、偏光片的破裂。 In order to increase the polarization degree of the polarizer layer and the polarizer, as mentioned above, in addition to increasing the elongation ratio and increasing the degree of boric acid crosslinking, it is also considered to increase the necking ratio. However, in these methods, the shrinkage force tends to increase when the polarizer layer or the polarizer is heated, and cracks of the polarizer layer or the polarizer tend to occur easily.

本發明之目的係提供具有高的光學特性之同時收縮力小的偏光膜及偏光性積層膜的製造方法。 An object of the present invention is to provide a polarizing film and a method for producing a polarizing laminated film having high optical properties and a small shrinkage force.

本發明,提供以下所示的偏光膜、偏光板,以及偏光性積層膜及偏光板的製造方法。 The present invention provides a polarizing film, a polarizing plate, and a method for producing a polarizing laminated film and a polarizing plate shown below.

〔1〕偏光膜,其係碘配向於聚乙烯醇系樹脂層的偏光膜;硼含有率為2.5重量%以上4.1重量%以下;視感度校正單體透過率(Ty)超出40.5%;波長475nm的平行吸光度/垂直吸光度所表示的比未達0.022。 [1] A polarizing film, which is a polarizing film in which iodine is aligned to a polyvinyl alcohol-based resin layer; the boron content is not less than 2.5% by weight and not more than 4.1% by weight; the transmittance (Ty) of a single element after correction of sensitivity exceeds 40.5%; the wavelength is 475nm The ratio represented by the parallel absorbance/perpendicular absorbance is less than 0.022.

〔2〕如〔1〕記載之偏光膜,其中在80℃下保持4小時時之吸收軸方向的寬度為2mm、每5μm厚度的收縮力未達1.77N/5μm。 [2] The polarizing film according to [1], wherein the width in the direction of the absorption axis is 2 mm and the shrinkage force per 5 μm thickness is less than 1.77 N/5 μm when kept at 80° C. for 4 hours.

〔3〕如〔1〕或〔2〕記載之偏光膜,其厚度為10μm以下。 [3] The polarizing film according to [1] or [2], which has a thickness of 10 μm or less.

〔4〕偏光板,其係於〔1〕至〔3〕中任一項記載之偏光膜的至少一側的面,具有保護膜。 [4] A polarizing plate having a protective film on at least one surface of the polarizing film according to any one of [1] to [3].

〔5〕偏光性積層膜的製造方法,依序具備:在基材膜的至少一側的面,形成聚乙烯醇系樹脂層,得到積層膜之樹脂層形成步驟;將前述積層膜延伸而得到延伸膜之延伸步驟;藉由將前述延伸膜的前述聚乙烯醇系樹脂層以碘染色,形成染色層而得到染色積層膜的染色步驟;藉由將前述染色積層膜的前述染色層以包含硼酸的交聯液交聯,形成交聯層而得到交聯積層膜的交聯步驟;以及藉由降低前述交聯積層膜的前述交聯層所包含的硼含有率,形成偏光片層而得到偏光性積層膜的去硼步驟; 其中前述去硼步驟具有前述交聯層與去硼液接觸之去硼液接觸步驟,前述去硼液具有比前述交聯液的硼酸濃度低的硼酸濃度;於前述去硼液接觸步驟,以小於前述交聯步驟中附加於附前述染色層的積層膜的張力的大小的方式,控制附加於前述交聯積層膜的張力的大小。 [5] A method for producing a polarizing laminated film comprising, in order: forming a polyvinyl alcohol-based resin layer on at least one surface of a base film to obtain a resin layer forming a laminated film; stretching the laminated film to obtain The stretching step of stretched film; the dyeing step of obtaining a dyed laminated film by dyeing the aforementioned polyvinyl alcohol-based resin layer of the aforementioned stretched film with iodine to form a dyed layer; the dyed layer of the aforementioned dyed laminated film containing boric acid The crosslinking solution is crosslinked to form a crosslinked layer to obtain a crosslinked laminated film; The boron-removing step of the laminated film; wherein the aforementioned boron-removing step has a boron-removing liquid contact step in which the aforementioned cross-linked layer is in contact with the boron-removing liquid, and the aforementioned boron-removing liquid has a boric acid concentration lower than that of the aforementioned cross-linking liquid; In the step of contacting the boron removal solution, the magnitude of the tension applied to the cross-linked laminated film is controlled so as to be smaller than the magnitude of the tension applied to the laminated film with the dyed layer in the aforementioned cross-linking step.

〔6〕偏光板的製造方法,依序包括:藉由〔5〕記載的製造方法,製造偏光性積層膜的步驟;於前述偏光片層之前述基材膜的相反側的面,貼合保護膜的步驟;以及剝離去除前述基材膜的步驟。 [6] A method for manufacturing a polarizing plate, comprising, in order: a step of manufacturing a polarizing laminate film by the manufacturing method described in [5]; attaching a protective film to the surface of the polarizer layer opposite to the base film. a step of film; and a step of peeling and removing the aforementioned substrate film.

根據本發明,可提供具有高的光學特性的同時收縮力受到抑制的偏光膜及偏光板。而且,根據本發明,可提供具有光學特性佳、收縮力小的偏光片層之偏光性積層膜的製造方法及偏光板的製造方法。 According to the present invention, it is possible to provide a polarizing film and a polarizing plate having high optical properties and suppressing shrinkage force. Furthermore, according to the present invention, it is possible to provide a method for producing a polarizing laminate film having a polarizer layer having excellent optical properties and a small shrinkage force, and a method for producing a polarizing plate.

1‧‧‧單面附保護膜之偏光板 1‧‧‧Polarizing plate with protective film on one side

2‧‧‧兩面附保護膜之偏光板 2‧‧‧Polarizing plate with protective film on both sides

5‧‧‧偏光片層 5‧‧‧polarizer layer

6‧‧‧聚乙烯醇系樹脂層 6‧‧‧Polyvinyl alcohol resin layer

6’‧‧‧聚乙烯醇系樹脂層 6’‧‧‧Polyvinyl alcohol resin layer

10‧‧‧第1保護膜 10‧‧‧The first protective film

15‧‧‧第1接著劑層 15‧‧‧The first adhesive layer

20‧‧‧第2保護膜 20‧‧‧Second protective film

25‧‧‧第2接著劑層 25‧‧‧Second Adhesive Layer

30‧‧‧基材膜 30‧‧‧Substrate film

30’‧‧‧基材膜 30’‧‧‧Substrate film

100‧‧‧積層膜 100‧‧‧Laminated film

200‧‧‧延伸膜 200‧‧‧stretch film

300‧‧‧偏光性積層膜 300‧‧‧Polarizing laminated film

400‧‧‧多層膜 400‧‧‧multilayer film

第1圖表示本發明之偏光性積層膜的製造方法及偏光板的製造方法之流程圖。 Fig. 1 shows a flowchart of a method of manufacturing a polarizing laminated film and a method of manufacturing a polarizing plate of the present invention.

第2圖表示在樹脂層形成步驟所得之積層膜的層構成之一例的剖面示意圖。 Fig. 2 is a schematic cross-sectional view showing an example of the layer configuration of the laminated film obtained in the resin layer forming step.

第3圖表示在延伸步驟所得之延伸膜的層構成之一例的剖面示意圖。 Fig. 3 is a schematic cross-sectional view showing an example of the layer constitution of the stretched film obtained in the stretching step.

第4圖表示在去硼步驟所得之偏光性積層膜的層構成之一例的剖面示意圖。 Fig. 4 is a schematic cross-sectional view showing an example of the layer constitution of the polarizing multilayer film obtained in the boron removal step.

第5圖表示在第1保護膜貼合步驟所得之附保護膜之偏光板的層構成之一例的剖面示意圖。 Fig. 5 is a schematic cross-sectional view showing an example of the layer configuration of a polarizing plate with a protective film obtained in the first protective film bonding step.

第6圖表示在剝離步驟所得之單面附保護膜之偏光板的層構成之一例的剖面示意圖。 Fig. 6 is a schematic cross-sectional view showing an example of the layer configuration of a polarizing plate with a protective film on one side obtained in the peeling step.

第7圖表示在第2保護膜貼合步驟所得之兩面附保護膜之偏光板的層構成之一例的剖面示意圖。 Fig. 7 is a schematic cross-sectional view showing an example of the layer configuration of a polarizing plate with protective films on both sides obtained in the second protective film bonding step.

〈偏光膜〉 <Polarizing film>

偏光膜,係碘配向於聚乙烯醇系樹脂層者,例如可得到作為後述偏光性積層膜的偏光片層。偏光膜,其硼含有率為2.5重量%以上4.1重量%以下,視感度校正單體透過率(Ty)超出40.5%,波長475nm的平行吸光度/垂直吸光度所表示的比未達0.022。偏光膜,係聚乙烯醇系樹脂層被延伸的延伸膜,該延伸係以單軸延伸較理想。 The polarizing film is one in which iodine is aligned to the polyvinyl alcohol-based resin layer, for example, a polarizer layer as a polarizing laminated film described later can be obtained. The polarizing film has a boron content of 2.5% to 4.1% by weight, a sensitivity-corrected single transmittance (Ty) exceeding 40.5%, and a ratio expressed by parallel absorbance/perpendicular absorbance at a wavelength of 475 nm of less than 0.022. The polarizing film is a stretched film in which a polyvinyl alcohol-based resin layer is stretched, and the stretching is preferably uniaxial stretching.

偏光膜中的硼,係來自用以交聯後述的聚乙烯醇系樹脂層的交聯液中的硼酸者。偏光膜的硼含有率大,亦即聚乙烯醇系樹脂層的交聯度高時,可提高偏光度等的光學特性,惟在加熱偏光膜時的收縮力有變大的傾向。 Boron in the polarizing film is derived from boric acid in a crosslinking solution for crosslinking a polyvinyl alcohol-based resin layer described later. When the boron content of the polarizing film is large, that is, when the degree of crosslinking of the polyvinyl alcohol-based resin layer is high, the optical properties such as the degree of polarization can be improved, but the shrinkage force when the polarizing film is heated tends to increase.

另一方面,偏光膜的硼含有率小,亦即交聯度低時,可使偏光膜在加熱時的收縮力變小,但有不易得到充分的耐水性及良好的光學特性的傾向。 On the other hand, when the boron content of the polarizing film is small, that is, when the degree of crosslinking is low, the shrinkage force of the polarizing film when heated can be reduced, but sufficient water resistance and good optical properties tend to be difficult to obtain.

偏光膜的硼含有率,可為2.5重量%以上4.1 重量%以下。藉此,可抑制偏光膜在加熱時產生的收縮力。偏光膜的硼含有率,較理想為2.6重量%以上4.0重量%以下,更理想為2.7重量%以上3.5重量%以下。偏光膜的硼含有率,係根據後述的實施例的記載測定。 The boron content of the polarizing film may be not less than 2.5% by weight and not more than 4.1% by weight. Thereby, the contraction force which a polarizing film generate|occur|produces at the time of heating can be suppressed. The boron content of the polarizing film is more preferably from 2.6% by weight to 4.0% by weight, more preferably from 2.7% by weight to 3.5% by weight. The boron content of the polarizing film was measured in accordance with the description in Examples described later.

偏光膜在80℃下保持4小時時之偏光膜的吸收軸方向(延伸方向)的寬度2mm、偏光膜每5μm厚度的收縮力,以未達1.77N/5μm較理想,以未達1.70N/5μm更理想,以1.60N/5μm以下更加理想,亦可為1.40N/5μm以下。收縮力的下限值,無特別限制,較理想地為0N/5μm,通常為0.1N/5μm以上,亦可為0.2N/5μm以上。另一方面,因偏光膜以不膨脹較理想,故以-0.01N/5μm以上較理想。偏光膜的收縮力,係根據後述的實施例的記載,測定偏光膜的收縮力所得的值(實測收縮力)及測定偏光膜的厚度所得的值,根據下式換算每5μm厚度所算出的值。 When the polarizing film is kept at 80°C for 4 hours, the width of the polarizing film in the direction of the absorption axis (extension direction) is 2mm, and the shrinkage force of the polarizing film per 5μm thickness is ideally less than 1.77N/5μm, and less than 1.70N/ 5 μm is more desirable, more preferably 1.60 N/5 μm or less, and may be 1.40 N/5 μm or less. The lower limit of the contraction force is not particularly limited, but is preferably 0 N/5 μm, usually 0.1 N/5 μm or more, and may be 0.2 N/5 μm or more. On the other hand, since the polarizing film is ideal not to expand, it is ideal to be -0.01N/5μm or more. The contraction force of the polarizing film is the value obtained by measuring the contraction force of the polarizing film (measured contraction force) and the value obtained by measuring the thickness of the polarizing film according to the description of the examples described later, and the value calculated per 5 μm thickness by conversion according to the following formula .

收縮力[N/5μm]=(偏光膜的實測收縮力[N])/(偏光膜的厚度(實測值)[μm])×5 Contraction force [N/5μm]=(measured contraction force of polarizing film [N])/(thickness of polarizing film (measured value)[μm])×5

如上述,提高聚乙烯醇系樹脂層的交聯度,偏光膜的硼含有率變大時,可提高偏光度等的光學特性,但偏光膜的收縮力變大。另一方面,降低聚乙烯醇系樹脂層的交聯度,偏光膜中的硼含有率變小時,難以得到良好的光學特性。 As described above, when the degree of crosslinking of the polyvinyl alcohol-based resin layer is increased to increase the boron content of the polarizing film, optical properties such as polarization degree can be improved, but the shrinkage force of the polarizing film becomes large. On the other hand, lowering the degree of cross-linking of the polyvinyl alcohol-based resin layer reduces the boron content in the polarizing film, making it difficult to obtain favorable optical properties.

所以,於偏光膜,波長475nm的平行吸光度/垂直吸光度所表示的比未達0.022。藉此,在可抑制偏光膜的收縮力的程度下,硼含有率變小,同時視感度校正 單體透過率(Ty)超出40.5%,視感度校正單體透過率(Ty)為41.5%時,可實現視感度校正偏光度(Py)超出99.994的良好的光學特性。視感度校正單體透過率(Ty)的下限值,較理想為41.0%以上,更理想為41.5%以上,上限值為50%以下,更理想為47%以下。視感度校正單體透過率(Ty)為41.5%時的視感度校正偏光度(Py)的下限值,較理想為99.995以上,更理想為99.996以上。 Therefore, in a polarizing film, the ratio represented by the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm is less than 0.022. In this way, the boron content rate becomes smaller to the extent that the shrinkage force of the polarizing film can be suppressed, and at the same time, the single transmittance (Ty) of the light sensitivity correction exceeds 40.5%. When the light sensitivity correction single transmittance (Ty) is 41.5% , can achieve good optical characteristics with a sensitivity-corrected degree of polarization (Py) exceeding 99.994. The lower limit of the sensitivity-corrected single transmittance (Ty) is preferably 41.0% or more, more preferably 41.5% or more, and the upper limit is 50% or less, more preferably 47% or less. The lower limit value of the sensitivity-corrected polarization degree (Py) when the sensitivity-corrected single transmittance (Ty) is 41.5% is preferably 99.995 or more, more preferably 99.996 or more.

根據偏光膜的波長475nm的平行吸光度/垂直吸光度所表示的比的規定,可提高偏光膜的光學特性的理由,可說明如下。被碘染色的聚乙烯醇系樹脂層中,碘吸附配向於聚乙烯醇系樹脂層。該吸附配向的碘形成I3 -、I5 -等的聚碘離子的錯合物。該等的錯合物中,在475nm具有吸收帶的聚碘離子的錯合物(I3 -錯合物),相較於其它聚碘離子的錯合物,因配向容易受到干擾,容易成為偏光膜的偏光度降低的原因。 The reason why the optical characteristics of the polarizing film can be improved by specifying the ratio represented by the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm of the polarizing film can be explained as follows. In the polyvinyl alcohol-based resin layer dyed with iodine, iodine is adsorbed and aligned to the polyvinyl alcohol-based resin layer. The iodine adsorbed and aligned forms complexes of polyiodide ions such as I 3 - , I 5 - and the like. Among these complexes, the polyiodide ion complex (I 3 -complex ) having an absorption band at 475nm, compared with other polyiodide ion complexes, is easily disturbed due to alignment, and is easy to become The reason why the degree of polarization of the polarizing film decreases.

而且,在波長475nm具有吸收帶的聚碘離子的錯合物中,也存在相對配向性高的錯合物與相對配向性低的錯合物。為了提高偏光膜的偏光度,於聚乙烯醇系樹脂層,在475nm具有吸收帶的聚碘離子的錯合物中,以增加相對配向性高的錯合物的含有率大者較理想。 Furthermore, in complexes of polyiodide ions having an absorption band at a wavelength of 475 nm, complexes with high relative alignment and complexes with low relative alignment also exist. In order to increase the degree of polarization of the polarizing film, in the polyvinyl alcohol-based resin layer, among polyiodide ion complexes having an absorption band at 475 nm, it is desirable to increase the content of the relatively high-alignment complex.

在475nm具有吸收帶的聚碘離子的錯合物中相對配向性高的錯合物的含有率,可用波長475nm的平行吸光度/垂直吸光度所表示的比進行評價。此處,波長475nm的平行吸光度,係從格蘭-湯姆森稜鏡(Grand Thomson Prism)射出的偏光的方向與試料(偏光膜)的透過軸平行時的透過率,換算為吸光度的值。而且,波長475nm的垂直吸光度,係從格蘭-湯姆森稜鏡(Grand Thomson Prism)射出的偏光的方向與試料(偏光膜)的透過軸垂直時的透過率,換算為吸光度的值。 The content of the polyiodide ion complex having an absorption band at 475 nm can be evaluated by the ratio represented by the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm. Here, the parallel absorbance at a wavelength of 475 nm is the transmittance when the direction of polarized light emitted from the Grand Thomson Prism is parallel to the transmission axis of the sample (polarizing film), and is converted into an absorbance value. In addition, the vertical absorbance at a wavelength of 475 nm is the transmittance when the direction of polarized light emitted from the Grand Thomson Prism is perpendicular to the transmission axis of the sample (polarizing film), and is converted into an absorbance value.

波長475nm的平行吸光度/垂直吸光度所表示的比越小時,平行吸光度小,垂直吸光度大。此係上述比越小,在475nm具有吸收帶的聚碘離子的錯合物中,在與偏光膜的透過軸垂直的方向(偏光膜的吸收軸方向)配向之相對配向性高的錯合物含有率變大。所以,藉由縮小上述比而可提高偏光膜的偏光度。 The smaller the ratio represented by the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm, the smaller the parallel absorbance and the larger the perpendicular absorbance. This means that the smaller the above-mentioned ratio, the complex of polyiodide ions having an absorption band at 475 nm is aligned in a direction perpendicular to the transmission axis of the polarizing film (direction of the absorption axis of the polarizing film) and has a high relative alignment. The content rate becomes larger. Therefore, the degree of polarization of the polarizing film can be increased by reducing the above ratio.

如此,藉由偏光膜在波長475nm的平行吸光度/垂直吸光度所表示的比未達0.022,配向性低的錯合物的量變小,可提高偏光膜的偏光度。上述比的上限值,更理想為未達0.0218,更加理想為未達0.0217,下限值,較理想為0.010以上,更理想為0.015以上。 In this way, when the ratio of the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm of the polarizing film is less than 0.022, the amount of complexes with low alignment is reduced, and the degree of polarization of the polarizing film can be increased. The upper limit of the ratio is more preferably less than 0.0218, more preferably less than 0.0217, and the lower limit is more preferably 0.010 or more, more preferably 0.015 or more.

偏光膜的厚度,較理想為10μm以下,更理想為7μm以下。藉由偏光膜的厚度為10μm以下,可實現後述的偏光板的薄型化。偏光膜的厚度的下限值,較理想為1μm以上,更理想為2μm以上。如此的偏光膜,也實現薄膜化,提高光學特性,可抑制收縮力。 The thickness of the polarizing film is preferably 10 μm or less, more preferably 7 μm or less. When the thickness of the polarizing film is 10 μm or less, it is possible to reduce the thickness of the polarizing plate described later. The lower limit of the thickness of the polarizing film is preferably 1 μm or more, more preferably 2 μm or more. Such a polarizing film can also be thinned, the optical characteristics can be improved, and the shrinkage force can be suppressed.

構成偏光膜的聚乙烯醇系樹脂層的聚乙烯醇系樹脂,可使用關於聚乙烯醇系樹脂層之後述者。而且,偏光膜,例如可根據後述的偏光性積層膜的製造方法製造。 As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin layer of the polarizing film, those described later for the polyvinyl alcohol-based resin layer can be used. In addition, the polarizing film can be produced, for example, according to the production method of the polarizing laminated film described later.

〈偏光板〉 <Polarizing plate>

偏光膜,可在其至少一側的面設置保護膜,成為偏光板。偏光板可為保護膜設置於偏光膜的單面的單面附保護膜之偏光板,亦可為保護膜設置於偏光膜的兩面之兩面附保護膜之偏光板。兩面附保護膜之偏光板的2個保護膜,可為相同種類的保護膜,亦可為不同種類的保護膜。 The polarizing film may be provided with a protective film on at least one surface thereof to form a polarizing plate. The polarizing plate may be a polarizing plate with a protective film on one side of the polarizing film, or a polarizing plate with protective films on both sides of the polarizing film. The two protective films of the polarizing plate with protective films on both sides may be the same type of protective film or may be different types of protective films.

關於構成保護膜的材料,可使用後述者,例如可根據後述的偏光板的製造方法製造。 As for the material constituting the protective film, those described later can be used, and it can be manufactured, for example, according to the manufacturing method of a polarizing plate described later.

(偏光板的用途) (Application of polarizing plate)

單面附保護膜之偏光板、兩面附保護膜之偏光板,貼合周邊構件成為複合偏光板,可成為如此的複合偏光板使用。作為周邊構件,例如貼合於保護膜上之防止劃傷用的保護膜;積層於保護膜上(例如兩面附保護膜之偏光板的情況)或偏光片層上(例如單面附保護膜之偏光板的情況)之貼合偏光板於顯示單元、其它光學構件用的黏著劑層;積層於黏著劑層的外表面之分隔膜;積層於保護膜上(例如兩面附保護膜之偏光板的情況)或偏光片層上(例如單面附保護膜之偏光板的情況)的如相位差膜的光學補償膜、其它光學功能性膜。 A polarizing plate with a protective film on one side, a polarizing plate with a protective film on both sides, can be used as such a composite polarizing plate by bonding peripheral components together to form a composite polarizing plate. As a peripheral member, such as a protective film attached to the protective film to prevent scratches; laminated on the protective film (such as the case of a polarizer with a protective film on both sides) or on the polarizer layer (such as a protective film on one side) In the case of polarizing plates), the adhesive layer used to attach the polarizing plate to the display unit and other optical components; the separator film laminated on the outer surface of the adhesive layer; laminated on the protective film (such as polarizing plates with protective films on both sides case) or on the polarizer layer (for example, in the case of a polarizer with a protective film on one side), an optical compensation film such as a retardation film, and other optical functional films.

周邊構件的一例之黏著劑層,在兩面附保護膜之偏光板時,可積層於任一保護膜的外表面,單面附保護膜之偏光板時,例如可積層於剝離面。形成黏著劑層的黏著劑,通常以(甲基)丙烯酸系樹脂、苯乙烯系樹脂、聚矽氧系樹脂等為基質聚合物,於其中添加如異氰酸酯化 合物、環氧化合物、氮丙啶化合物的交聯劑之黏著劑組成物所構成。再含有微粒子,可成為顯示光散射性的黏著劑層。黏著劑層的厚度,通常為1至40μm,較理想為3至25μm。 The adhesive layer as an example of the peripheral member can be laminated on the outer surface of either protective film in the case of a polarizing plate with protective films on both sides, or on the peeling surface in the case of a polarizing plate with a protective film on one side. The adhesive forming the adhesive layer usually uses (meth)acrylic resin, styrene resin, polysiloxane resin, etc. It is composed of the adhesive composition of the cross-linking agent. Further containing fine particles, it can become an adhesive layer exhibiting light scattering properties. The thickness of the adhesive layer is usually 1 to 40 μm, preferably 3 to 25 μm.

而且,作為周邊構件的一例之光學功能性膜,例如透過某種的偏光、反射顯示與其相反性質的偏光的光之反射型偏光膜;表面具有凹凸形狀的附防眩功能的膜;附表面抗反射的膜;表面具有反射功能的反射膜;合併具有反射功能及透過功能的半透過反射膜;視角補償膜等。 Furthermore, an optical functional film as an example of a peripheral member includes, for example, a reflective polarizing film that transmits a certain polarized light and reflects light that exhibits polarized light of the opposite nature; Reflective film; reflective film with reflective function on the surface; semi-transparent reflective film with reflective function and transmission function; viewing angle compensation film, etc.

〈偏光性積層膜的製造方法〉 <Manufacturing method of polarizing laminated film>

參考第1圖,偏光板的製造中間體之偏光性積層膜,藉由依序包含以下步驟而製造:在基材膜的至少一側的面形成聚乙烯醇系樹脂層而得到積層膜之樹脂層形成步驟S10;將前述積層膜延伸而得到延伸膜之延伸步驟S20;藉由將前述延伸膜的前述聚乙烯醇系樹脂層以碘染色形成染色層而得到染色積層膜的染色步驟S30;藉由將前述染色積層膜的前述染色層以包含硼酸的交聯液交聯形成交聯層而得到交聯積層膜的交聯步驟S40;藉由降低前述交聯積層膜的前述交聯層所含的硼含有率形成偏光片層而得到偏光性積層膜的去硼步驟S50。 Referring to Fig. 1, the polarizing laminated film, which is an intermediate in the production of polarizing plates, is produced by sequentially including the following steps: forming a polyvinyl alcohol-based resin layer on at least one surface of the base film to obtain a resin layer of the laminated film forming step S10; stretching step S20 of stretching the laminated film to obtain a stretched film; dyeing step S30 of obtaining a dyed laminated film by dyeing the polyvinyl alcohol-based resin layer of the stretched film with iodine to form a dyed layer; The crosslinking step S40 of obtaining the crosslinked laminated film by crosslinking the dyed layer of the dyed laminated film with a crosslinking solution containing boric acid to form a crosslinked layer; by reducing the Boron Content Forming a polarizer layer to obtain a boron removal step S50 of a polarizing laminated film.

再者,所謂本發明的偏光性積層膜,係指具備基材膜及積層於其至少一側的面上之偏光片層,且沒 有貼合保護膜者。後述的第1保護膜貼合步驟S60中,於偏光片層貼合第1保護膜所成的偏光性積層膜,於以下,為了與偏光性積層膜區分,亦稱為「附保護膜的偏光性積層膜」。 Furthermore, the so-called polarizing laminated film of the present invention refers to a film having a substrate film and a polarizer layer laminated on at least one surface thereof, and without a protective film attached thereto. In the first protective film bonding step S60 described later, the polarizing laminated film formed by bonding the first protective film to the polarizer layer is hereinafter also referred to as "polarizer with protective film" in order to distinguish it from the polarizing laminated film. Laminated film".

(1)樹脂層形成步驟S10 (1) Resin layer forming step S10

參考第2圖,本步驟係於基材膜30的至少一側的面形成聚乙烯醇系樹脂層6而得到積層膜100的步驟。該聚乙烯醇系樹脂層6,係經歷延伸步驟S20、染色步驟S30、交聯步驟S40及去硼步驟S50而成為偏光片層5的層。聚乙烯醇系樹脂層6係可藉由將含有聚乙烯醇系樹脂的塗佈液塗佈於基材膜30的單面或兩面使塗佈層乾燥而形成。藉由如此的塗佈而形成聚乙烯醇系樹脂層6的方法,在容易得到薄膜的偏光片層5之點上為有利。樹脂層形成步驟S10,一般的情況下傳統上係可從長條的基材膜30的捲物之膜卷連續地捲出基材膜30,其可在傳送的同時連續進行。膜的傳送係可使用導輥等進行。 Referring to FIG. 2 , this step is a step of forming a polyvinyl alcohol-based resin layer 6 on at least one surface of a base film 30 to obtain a laminated film 100 . The polyvinyl alcohol-based resin layer 6 is a layer that becomes the polarizer layer 5 through the stretching step S20 , the dyeing step S30 , the crosslinking step S40 and the boron removal step S50 . The polyvinyl alcohol-based resin layer 6 can be formed by applying a coating solution containing a polyvinyl alcohol-based resin to one or both surfaces of the base film 30 and drying the coated layer. The method of forming the polyvinyl alcohol-based resin layer 6 by such coating is advantageous in that it is easy to obtain the polarizer layer 5 of a thin film. Generally, the resin layer forming step S10 can continuously unwind the base film 30 from the film roll of the roll of the long base film 30 conventionally, and can be carried out continuously while conveying. The transport system of the film can be performed using a guide roll or the like.

(基材膜) (substrate film)

基材膜30,可由熱塑性樹脂構成,其中以由透明性、機械強度、熱安定性、延伸性等佳的熱塑性樹脂構成者較理想。如此的熱塑性樹脂的具體例,例如包括如鏈狀聚烯烴系樹脂、環狀聚烯烴系樹脂(降莰烯系樹脂等)的聚烯烴系樹脂;聚酯系樹脂;(甲基)丙烯酸系樹脂;如纖維素三乙酸酯、纖維素二乙酸酯的纖維素酯系樹脂;聚碳酸酯系樹脂;聚乙烯醇系樹脂;聚乙酸乙烯酯系樹脂;聚芳酯系 樹脂;聚苯乙烯系樹脂;聚醚碸系樹脂;聚碸系樹脂;聚醯胺系樹脂;聚醯亞胺系樹脂;以及該等的混合物、共聚物等。 The base film 30 may be made of a thermoplastic resin, among which those made of a thermoplastic resin good in transparency, mechanical strength, thermal stability, elongation, etc. are preferable. Specific examples of such thermoplastic resins include, for example, polyolefin-based resins such as chain polyolefin-based resins and cyclic polyolefin-based resins (norbornene-based resins, etc.); polyester-based resins; (meth)acrylic resins ; Cellulose ester resins such as cellulose triacetate and cellulose diacetate; polycarbonate resins; polyvinyl alcohol resins; polyvinyl acetate resins; polyarylate resins; polystyrene Polyether-based resins; polyether-based resins; polyamide-based resins; polyamide-based resins; polyimide-based resins; and their mixtures, copolymers, etc.

基材膜30,可為1種或2種以上的熱塑性樹脂所構成的1層樹脂層所構成的單層構造,亦可為1種或2種以上的熱塑性樹脂所構成的樹脂層複數積層的多層構造。基材膜30,以後述的延伸步驟S20延伸積層膜100時,在延伸聚乙烯醇系樹脂層6的較佳延伸溫度下可延伸的樹脂所構成者較理想。 The base film 30 may be a single-layer structure composed of one resin layer composed of one or more thermoplastic resins, or may be a multi-layered resin layer composed of one or two or more thermoplastic resins. Multi-layer construction. The base film 30 is preferably composed of a resin that can be stretched at a preferable stretching temperature for stretching the polyvinyl alcohol-based resin layer 6 when the laminated film 100 is stretched in the stretching step S20 described later.

作為鏈狀聚烯烴系樹脂,除了如聚丙烯樹脂的鏈狀烯烴的均聚物以外,例如2種以上的鏈狀烯烴所構成的共聚物。鏈狀聚烯烴系樹脂所構成的基材膜30,在容易安定地高倍率延伸之點上較理想。其中,基材膜30以聚丙烯系樹脂(丙烯的均聚物之聚丙烯樹脂、或以丙烯為主體的共聚物)、聚乙烯系樹脂(乙烯的均聚物之聚乙烯樹脂、或以乙烯為主體的共聚物)等所構成者更理想。 The chain polyolefin-based resin includes, for example, a copolymer composed of two or more chain olefins other than a homopolymer of chain olefins such as polypropylene resin. The base film 30 made of a chain polyolefin resin is preferable in that it is easy to stretch stably at a high ratio. Among them, the base film 30 is made of polypropylene resin (polypropylene resin of a homopolymer of propylene, or a copolymer mainly composed of propylene), polyethylene resin (polyethylene resin of a homopolymer of ethylene, or a copolymer of ethylene It is more preferable to consist of a copolymer as the main body).

適合使用作為構成基材膜30的熱塑性樹脂的例之一的以丙烯為主體的共聚物,係丙烯及可與其共聚的其它單體的共聚物。 A copolymer mainly composed of propylene, which is an example of the thermoplastic resin constituting the base film 30 , is a copolymer of propylene and other monomers copolymerizable therewith.

作為可與丙烯共聚的其它單體,例如乙烯、α-烯烴。作為α-烯烴,以使用碳數4以上的α-烯烴較理想,更理想為碳數4至10的α-烯烴。碳數4至10的α-烯烴的具體例,包括例如1-丁烯、1-戊烯、1-己烯、1-庚烯、1-辛烯、1-癸烯的直鏈狀單烯烴類;如3-甲基-1-丁烯、 3-甲基-1-戊烯、4-甲基-1-戊烯的分支狀單烯烴類;乙烯基環己烷等。丙烯及可與其共聚的其它單體的共聚物,可為無規共聚物,亦可為嵌段共聚物。 As other monomers copolymerizable with propylene, for example, ethylene, α-olefin. As the α-olefin, an α-olefin having 4 or more carbon atoms is preferably used, more preferably an α-olefin having 4 to 10 carbon atoms. Specific examples of α-olefins having 4 to 10 carbon atoms include linear monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and 1-decene Classes; branched monoolefins such as 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene; vinylcyclohexane, etc. The copolymer of propylene and other monomers that can be copolymerized with it can be a random copolymer or a block copolymer.

上述其它單體的含量,在共聚物中例如為0.1至20重量%,較理想為0.5至10重量%。共聚物中的其它單體的含量,根據「高分子分析手冊」(1995年、紀伊國屋書店發行)的第616頁記載的方法,藉由進行紅外線(IR)光譜的測定而求得。 The content of the above-mentioned other monomers in the copolymer is, for example, 0.1 to 20% by weight, preferably 0.5 to 10% by weight. The content of other monomers in the copolymer was determined by performing infrared (IR) spectrum measurement according to the method described on page 616 of "Polymer Analysis Handbook" (published by Kinokuniya Shoten in 1995).

上述之中,作為聚丙烯系樹脂,以使用丙烯均聚物、丙烯-乙烯無規共聚物、丙烯-1-丁烯無規共聚物或丙烯-乙烯-1-丁烯無規共聚物較理想。 Among the above, it is preferable to use a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, or a propylene-ethylene-1-butene random copolymer as the polypropylene-based resin. .

聚丙烯系樹脂的立體規則性,實質上為等規或間規較理想。實質上具有等規或間規的立體規則性之聚丙烯系樹脂所構成的基材膜30,其處理性較好的同時,在高溫環境下之機械強度佳。 The stereoregularity of polypropylene-based resins is essentially isotactic or syndiotactic, which is ideal. The base film 30 made of polypropylene-based resin substantially having isotactic or syndiotactic stereoregularity has good handling properties and good mechanical strength under high temperature environment.

環狀聚烯烴系樹脂,係環狀烯烴作為聚合單元聚合的樹脂的總稱,例如日本特開平1-240517號公報、日本特開平3-14882號公報、日本特開平3-122137號公報等記載的樹脂。列舉環狀聚烯烴系樹脂的具體例時,係有環狀烯烴的開環(共)聚合物、環狀烯烴的加成聚合物、環狀烯烴與如乙烯、丙烯的鏈狀烯烴的共聚物(代表性為無規共聚物)及該等用不飽和羧酸、其衍生物改性的接枝共聚物以及該等的氫化物等。其中,使用作為環狀烯烴,較理想為使用如降莰烯、多環降莰烯系單體的降莰烯系單 體之降莰烯系樹脂。 Cyclic polyolefin-based resins are a general term for resins polymerized with cyclic olefins as polymerized units, such as those described in JP-A-1-240517, JP-3-14882, JP-3-122137, etc. resin. When citing specific examples of cyclic polyolefin-based resins, there are ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, and copolymers of cyclic olefins and chain olefins such as ethylene and propylene. (Representatively random copolymers) and these graft copolymers modified with unsaturated carboxylic acids and their derivatives, and their hydrogenated products. Among them, as the cyclic olefin, it is preferable to use a norbornene-based resin such as a norbornene-based monomer such as norbornene and a polycyclic norbornene-based monomer.

聚酯系樹脂為具有酯鍵之樹脂,一般為多元羧酸或其衍生物與多元醇的縮聚物所成者。作為多元羧酸或其衍生物,可使用2價之二羧酸或其衍生物,例如對苯二甲酸、間苯二甲酸、對苯二甲酸二甲酯、萘二羧酸二甲酯。作為多元醇,可使用2價之二醇,例如乙二醇、丙二醇、丁二醇、新戊二醇、環己烷二甲醇。 Polyester-based resins are resins with ester bonds, and are generally polycondensates of polycarboxylic acids or their derivatives and polyhydric alcohols. As the polycarboxylic acid or its derivative, divalent dicarboxylic acid or its derivative, for example, terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalene dicarboxylate can be used. As the polyhydric alcohol, divalent diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, and cyclohexanedimethanol can be used.

作為聚酯系樹脂之代表例,例如對苯二甲酸與乙二醇的縮聚物之聚對苯二甲酸乙二酯。聚對苯二甲酸乙二酯為結晶性樹脂,結晶化處理前的狀態者,容易實施延伸等的處理。依需要,可藉由延伸時或延伸後的熱處理等進行結晶化處理。而且,藉由聚對苯二甲酸乙二酯的骨架,再與其它種的單體共聚,結晶性降低(或成為非晶性)的共聚聚酯也適合使用。作為如此樹脂的例,例如環己烷二甲醇、間苯二甲酸共聚者。該等樹脂因延伸性佳而適合使用。 As a representative example of the polyester-based resin, polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol, is exemplified. Polyethylene terephthalate is a crystalline resin, and it is easy to perform stretching and other treatments in the state before crystallization treatment. If necessary, crystallization treatment may be performed by heat treatment during stretching or after stretching. Furthermore, copolyesters whose crystallinity is reduced (or become amorphous) by copolymerization with other types of monomers through the skeleton of polyethylene terephthalate are also suitable for use. Examples of such resins include those copolymerized with cyclohexanedimethanol and isophthalic acid. These resins are suitable for use due to their good extensibility.

列舉聚對苯二甲酸乙二酯及其共聚物以外的聚酯系樹脂的具體例時,例如聚對苯二甲酸丁二酯、聚萘二甲酸乙二酯、聚萘二甲酸丁二酯、聚對苯二甲酸丙二酯、聚萘二甲酸丙二酯、聚對苯二甲酸環己烷二甲酯、聚萘二甲酸環己烷二甲酯。 When specific examples of polyester-based resins other than polyethylene terephthalate and its copolymers are given, for example, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, Polytrimethylene terephthalate, Polytrimethylene naphthalate, Poly(cyclohexanedimethylene terephthalate), Poly(cyclohexanedimethylene naphthalate).

(甲基)丙烯酸系樹脂,係以具有(甲基)丙烯醯基的化合物為主要構成的單體之樹脂。(甲基)丙烯酸系樹脂的具體例,例如包括如聚甲基丙烯酸甲酯之聚(甲基) 丙烯酸酯;甲基丙烯酸甲酯-(甲基)丙烯酸共聚物;甲基丙烯酸甲酯-(甲基)丙烯酸酯共聚物;甲基丙烯酸甲酯-丙烯酸酯-(甲基)丙烯酸共聚物;(甲基)丙烯酸甲酯-苯乙烯共聚物(MS樹脂等);甲基丙烯酸甲酯與具有脂環族烴基的化合物之共聚物(例如甲基丙烯酸甲酯-甲基丙烯酸環己酯共聚物、甲基丙烯酸甲酯-(甲基)丙烯酸降莰酯共聚物等)。較理想為使用如聚(甲基)丙烯酸甲酯之聚(甲基)丙烯酸C1-6烷酯為主成分的聚合物,更理想為使用甲基丙烯酸甲酯為主成分(50至100重量%,較理想為70至100重量%)之甲基丙烯酸甲酯系樹脂。 (Meth)acrylic resin is a resin mainly composed of a compound having a (meth)acryl group as a monomer. Specific examples of (meth)acrylic resins include, for example, poly(meth)acrylate such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate-( Meth) acrylate copolymer; methyl methacrylate-acrylate-(meth)acrylic acid copolymer; (meth)methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate with Copolymers of alicyclic hydrocarbon-based compounds (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.). It is more desirable to use poly(meth)acrylate C 1-6 alkyl ester as the main component polymer such as poly(meth)acrylate, and it is more desirable to use methyl methacrylate as the main component (50 to 100 wt. %, preferably 70 to 100% by weight) of methyl methacrylate resin.

纖維素酯系樹脂係纖維素與脂肪酸的酯。纖維素酯系樹脂的具體例係包括纖維素三乙酸酯、纖維素二乙酸酯、纖維素三丙酸酯、纖維素二丙酸酯。而且,可使用該等的共聚物、羥基的一部分用其它取代基修飾者。該等之中,特別理想為纖維素三乙酸酯(三乙醯基纖維素)。纖維素三乙酸酯,有許多製品市售,在取得容易性、成本之點上為有利。 Cellulose ester-based resins are esters of cellulose and fatty acids. Specific examples of cellulose ester-based resins include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Furthermore, these copolymers and those in which a part of the hydroxyl groups are modified with other substituents can be used. Among these, cellulose triacetate (triacetyl cellulose) is particularly desirable. Cellulose triacetate is commercially available in many products and is advantageous in terms of ease of acquisition and cost.

聚碳酸酯系樹脂為隔著碳酸酯基鍵結單體單元之聚合物所構成之工程塑膠,係具有高耐衝擊性、耐熱性、阻燃性、透明性的樹脂。構成基材膜30的聚碳酸酯系樹脂,為了降低光彈性係數,亦可為修飾聚合物骨架之被稱為改性聚碳酸酯的樹脂、改良波長依存性的共聚聚碳酸酯。 Polycarbonate-based resins are engineering plastics composed of polymers bonded to monomer units through carbonate groups. They are resins with high impact resistance, heat resistance, flame retardancy, and transparency. The polycarbonate-based resin constituting the base film 30 may be a resin called a modified polycarbonate that modifies a polymer skeleton in order to lower the photoelastic coefficient, or a copolymerized polycarbonate that improves wavelength dependence.

以上之中,從延伸性、耐熱性等的觀點, 以使用聚丙烯系樹脂較理想。 Among the above, it is preferable to use polypropylene-based resins from the viewpoint of elongation, heat resistance, and the like.

於基材膜30,除了上述熱塑性樹脂外,可包含任意適合的添加劑。作為添加劑,例如紫外線吸收劑、抗氧化劑、潤滑劑、塑化劑、離型劑、著色防止劑、阻燃劑、成核劑、抗靜電劑、顏料、著色劑等。基材膜30中的熱塑性樹脂的含量,較理想為50至100重量%,更理想為50至99重量%,更加理想為60至98重量%,特別理想為70至97重量%。 In addition to the above-mentioned thermoplastic resin, the base film 30 may contain arbitrary appropriate additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the base film 30 is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably 70 to 97% by weight.

基材膜30的厚度,從強度、處理性等之點上,通常為1至500μm,較理想為1至300μm,更理想為5至200μm,更加理想為5至150μm。 The thickness of the base film 30 is usually 1 to 500 μm, preferably 1 to 300 μm, more preferably 5 to 200 μm, and still more preferably 5 to 150 μm from the viewpoint of strength and handleability.

(聚乙烯醇系樹脂層的形成) (Formation of polyvinyl alcohol-based resin layer)

塗佈於基材膜30的塗佈液,較理想為聚乙烯醇系樹脂的粉末溶解於良溶劑(例如水)所得之聚乙烯醇系樹脂溶液。作為聚乙烯醇系樹脂,可使用聚乙酸乙烯酯系樹脂經皂化者。聚乙酸乙烯酯系樹脂,除了乙酸乙烯酯的均聚物之聚乙酸乙烯酯以外,例如乙酸乙烯酯及可與其共聚之其它單體的共聚物。 The coating liquid applied to the base film 30 is preferably a polyvinyl alcohol-based resin solution obtained by dissolving polyvinyl alcohol-based resin powder in a good solvent (eg, water). As the polyvinyl alcohol-based resin, saponified polyvinyl acetate-based resin can be used. Polyvinyl acetate-based resins include, for example, copolymers of vinyl acetate and other monomers copolymerizable therewith, other than polyvinyl acetate which is a homopolymer of vinyl acetate.

作為可與乙酸乙烯酯共聚之其它單體,例如不飽和羧酸類、烯烴類、乙烯醚類、不飽和磺酸類、具有銨基的丙烯醯胺類等。 Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having ammonium groups, and the like.

聚乙烯醇系樹脂的皂化度可為80.0至100.0莫耳%的範圍,較理想為90.0至99.5莫耳%的範圍,更理想為94.0至99.0莫耳%的範圍。皂化度未達80.0莫耳% 時,會有偏光板的耐水性及耐濕熱性低的情形。於使用皂化度超出99.5莫耳%之聚乙烯醇系樹脂時,二色性色素的碘的染色速度變慢,生產性低,同時無法得到具有充分的偏光性能之偏光板。 The degree of saponification of the polyvinyl alcohol-based resin may be in the range of 80.0 to 100.0 mol%, preferably in the range of 90.0 to 99.5 mol%, more preferably in the range of 94.0 to 99.0 mol%. When the degree of saponification is less than 80.0 mol %, the water resistance and heat and humidity resistance of the polarizing plate may be low. When a polyvinyl alcohol-based resin with a degree of saponification exceeding 99.5 mol% is used, the iodine dyeing speed of the dichroic dye becomes slow, and productivity is low, and a polarizing plate having sufficient polarizing performance cannot be obtained.

所謂皂化度,係指聚乙烯醇系樹脂的原料之聚乙酸乙烯酯系樹脂所包含的乙酸基(乙醯氧基:-OCOCH3)藉由皂化步驟而變成羥基的比例以單元比(莫耳%)表示者,以下述式定義:皂化度(莫耳%)=100×(羥基數)÷(羥基數+乙酸基數)。皂化度可根據JIS K 6726-1994求得。皂化度越高,表示羥基的比例越高,所以表示阻礙結晶化的乙酸基的比例低。 The so-called degree of saponification refers to the ratio of the acetic acid group (acetyloxy group: -OCOCH 3 ) contained in the polyvinyl acetate resin, which is the raw material of the polyvinyl alcohol resin, into a hydroxyl group through the saponification step, expressed in unit ratio (molar %) is defined by the following formula: degree of saponification (mole %)=100×(number of hydroxyl groups)÷(number of hydroxyl groups+number of acetic acid groups). The degree of saponification can be obtained in accordance with JIS K 6726-1994. The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetic acid groups that inhibit crystallization.

聚乙烯醇系樹脂,可為一部分改性之改性聚乙烯醇。例如聚乙烯醇系樹脂用乙烯、丙烯等的烯烴;丙烯酸、甲基丙烯酸、丁烯酸等不飽和羧酸;不飽和羧酸的烷酯、丙烯醯胺等改性者。改性的比例係以未達30莫耳%較理想,以未達10%更理想。進行超出30莫耳%之改性時,二色性色素之碘變得難以吸附,有無法得到具有充分的偏光性能之偏光板的傾向。 The polyvinyl alcohol-based resin may be partially modified modified polyvinyl alcohol. For example, polyvinyl alcohol-based resins are modified with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; alkyl esters of unsaturated carboxylic acids, and acrylamide. The ratio of modification is ideally less than 30 mol%, more ideally less than 10%. When the modification exceeds 30 mol%, iodine of the dichroic dye becomes difficult to adsorb, and a polarizing plate having sufficient polarizing performance tends not to be obtained.

聚乙烯醇系樹脂的平均聚合度,較理想為100至10000,更理想為1500至8000,更加理想為2000至5000。聚乙烯醇系樹脂的平均聚合度,也可根據JIS K 6726-1994求得。平均聚合度未達100時,難以得到較佳的偏光性能,超出10000時,對溶劑的溶解性惡化,於後述的偏光性積層膜的製造方法,聚乙烯醇系樹脂層的形成 變困難。 The average degree of polymerization of the polyvinyl alcohol-based resin is preferably from 100 to 10,000, more preferably from 1,500 to 8,000, and still more preferably from 2,000 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can also be obtained in accordance with JIS K 6726-1994. When the average degree of polymerization is less than 100, it is difficult to obtain good polarizing performance, and when it exceeds 10000, the solubility to solvents deteriorates, and it becomes difficult to form a polyvinyl alcohol-based resin layer in the production method of a polarizing laminated film described later.

塗佈液可依需要而含有塑化劑、界面活性劑等的添加劑。作為塑化劑,可使用多元醇或其縮合物等,例如丙三醇、二丙三醇、三丙三醇、乙二醇、丙二醇、聚乙二醇等。添加劑的調配量,適合為聚乙烯醇系樹脂的20重量%以下。 The coating liquid may contain additives such as plasticizers and surfactants as necessary. As the plasticizer, a polyhydric alcohol or a condensate thereof, such as glycerol, diglycerol, triglycerol, ethylene glycol, propylene glycol, polyethylene glycol, etc., can be used. The compounding amount of the additive is suitably 20% by weight or less of the polyvinyl alcohol-based resin.

上述塗佈液塗佈於基材膜30的方法,可從線棒塗佈法;如反向塗佈法、凹版塗佈法等的輥塗佈法;狹縫塗佈法;缺角輪塗佈法;唇式塗佈法;旋轉塗佈法;網版塗佈法;噴注式塗佈法;浸塗法;噴塗法等的方法適當地選擇。 The method for applying the above-mentioned coating liquid to the substrate film 30 can be a wire bar coating method; a roll coating method such as a reverse coating method, a gravure coating method, etc.; a slit coating method; Cloth method; lip coating method; spin coating method; screen coating method; jet coating method; dip coating method; spray coating method and the like are appropriately selected.

塗佈層(乾燥前的聚乙烯醇系樹脂層)的乾燥溫度及乾燥時間,係依據塗佈液中所含的溶劑之種類設定。乾燥溫度例如為50至200℃,較理想為60至150℃。溶劑包含水時,乾燥溫度以80℃以上較理想。 The drying temperature and drying time of the coating layer (polyvinyl alcohol-based resin layer before drying) are set according to the type of solvent contained in the coating liquid. The drying temperature is, for example, 50 to 200°C, preferably 60 to 150°C. When the solvent contains water, the drying temperature is preferably 80°C or higher.

聚乙烯醇系樹脂層6,可只形成於基材膜30的一側的面,亦可形成於兩面。形成於兩面時,可抑制偏光性積層膜在製造時所產生的膜的捲曲,同時可由一片偏光性積層膜得到2片偏光板,在偏光板的生產效率的面上亦有利。 The polyvinyl alcohol-based resin layer 6 may be formed on only one surface of the base film 30, or may be formed on both surfaces. When it is formed on both sides, it can suppress the curling of the polarizing laminated film during production, and at the same time, two polarizing plates can be obtained from one polarizing laminated film, which is also advantageous in terms of production efficiency of polarizing plates.

積層膜100之聚乙烯醇系樹脂層6的厚度以3至30μm較理想,以5至20μm更理想。只要是具有該範圍內的厚度之聚乙烯醇系樹脂層6,經過後述的延伸步驟S20及染色步驟S30,二色性色素的碘的染色性良好, 偏光性能佳,且可得到充分薄(例如厚度10μm以下)的偏光片層5。 The thickness of the polyvinyl alcohol-based resin layer 6 of the laminated film 100 is preferably 3 to 30 μm, more preferably 5 to 20 μm. As long as the polyvinyl alcohol-based resin layer 6 has a thickness within this range, after the stretching step S20 and the dyeing step S30 described later, the iodine dyeability of the dichroic dye is good, the polarizing performance is good, and it can be sufficiently thin (such as A polarizer layer 5 with a thickness of 10 μm or less).

於塗佈液的塗佈前,為了提高基材膜30與聚乙烯醇系樹脂層6的密著性,至少於形成聚乙烯醇系樹脂層6側的基材膜30的表面,可實施電暈處理、電漿處理、火焰(flame)處理等。而且,因相同的理由,亦可於基材膜30上隔著底塗層等形成聚乙烯醇系樹脂層6。 Before the coating of the coating liquid, in order to improve the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6, at least the surface of the base film 30 on the side where the polyvinyl alcohol-based resin layer 6 is formed, can be electroplated. Halo treatment, plasma treatment, flame treatment, etc. In addition, for the same reason, the polyvinyl alcohol-based resin layer 6 may be formed on the base film 30 through a primer layer or the like.

底塗層,可將底塗層形成用塗佈液塗佈於基材膜30的表面後,藉由使其乾燥而形成。該塗佈液,包含可發揮基材膜30與聚乙烯醇系樹脂層6兩者某種強度之密著力之成分,通常係包含賦予如此的密著力之樹脂成分及溶劑。作為樹脂成分,較理想為使用透明性、熱安定性、延伸性等佳之熱塑性樹脂,例如(甲基)丙烯酸系樹脂、聚乙烯醇系樹脂等。其中,使用賦予良好的密著力之聚乙烯醇系樹脂較理想。更理想為聚乙烯醇樹脂。作為溶劑,通常使用可溶解上述樹脂成分的一般有機溶劑、水系溶劑,從水作為溶劑的塗佈液形成底塗層者較理想。 The undercoat layer can be formed by applying the coating liquid for undercoat layer formation to the surface of the base film 30 and then drying it. The coating liquid contains a component capable of exerting a certain level of adhesive force between the base film 30 and the polyvinyl alcohol-based resin layer 6, and usually includes a resin component and a solvent that impart such an adhesive force. As the resin component, it is preferable to use a thermoplastic resin excellent in transparency, thermal stability, extensibility, etc., such as (meth)acrylic resin, polyvinyl alcohol-based resin, and the like. Among them, it is preferable to use a polyvinyl alcohol-based resin that imparts good adhesion. More preferably, it is a polyvinyl alcohol resin. As a solvent, a general organic solvent or an aqueous solvent that can dissolve the above-mentioned resin components is usually used, and it is preferable to form an undercoat layer from a coating solution in which water is used as a solvent.

為了提高底塗層的強度,可於底塗層形成用塗佈液中添加交聯劑。交聯劑的具體例係包括環氧系、異氰酸酯系、二醛系、金屬系(例如金屬鹽、金屬氧化物、金屬氫氧化物、有機金屬化合物)、高分子系的交聯劑。使用聚乙烯醇系樹脂作為形成底塗層的樹脂成分時,適合使用聚醯胺環氧樹脂、羥甲基化三聚氰胺樹脂、二醛系交聯劑、金屬螫合劑化合物系交聯劑等。 In order to increase the strength of the undercoat layer, a crosslinking agent may be added to the coating liquid for undercoat layer formation. Specific examples of the crosslinking agent include epoxy-based, isocyanate-based, dialdehyde-based, metal-based (such as metal salts, metal oxides, metal hydroxides, organometallic compounds), and polymer-based cross-linking agents. When polyvinyl alcohol-based resin is used as the resin component for forming the undercoat layer, polyamide epoxy resin, methylolated melamine resin, dialdehyde-based crosslinking agent, metal chelating compound-based crosslinking agent, and the like are suitably used.

底塗層的厚度係以0.05至1μm左右較理想,更理想為0.1至0.4μm。若比0.05μm薄,基材膜30與聚乙烯醇系樹脂層6的密著力之提高效果變小。 The thickness of the primer layer is preferably about 0.05 to 1 μm, more preferably 0.1 to 0.4 μm. If it is thinner than 0.05 μm, the effect of improving the adhesive force between the base film 30 and the polyvinyl alcohol-based resin layer 6 becomes small.

將底塗層形成用塗佈液塗佈於基材膜30的方法,可與聚乙烯醇系樹脂層形成用的塗佈液相同。底塗層形成用塗佈液所構成的塗佈層的乾燥溫度,例如為50至200℃,較理想為60至150℃。在溶劑包含水時,乾燥溫度以80℃以上較理想。 The method of applying the coating liquid for undercoat layer formation to the base film 30 may be the same as the coating liquid for polyvinyl-alcohol-type resin layer formation. The drying temperature of the coating layer composed of the coating liquid for forming an undercoat layer is, for example, 50 to 200°C, preferably 60 to 150°C. When the solvent contains water, the drying temperature is preferably 80°C or higher.

(2)延伸步驟S20 (2) Extending step S20

參考第3圖,本步驟係將積層膜100進行延伸而得到延伸的基材膜30’及聚乙烯醇系樹脂層6’所構成的延伸膜200之步驟。延伸通常為單軸延伸。延伸步驟S20,傳統上係一邊傳送長條的積層膜100,或從長條的積層膜100的捲物的膜卷連續地捲出積層膜100,其可在傳送的同時連續進行。膜的傳送係可使用導輥等。 Referring to FIG. 3, this step is a step of stretching the laminated film 100 to obtain the stretched film 200 composed of the stretched base film 30' and the polyvinyl alcohol-based resin layer 6'. The extension is usually uniaxial. The stretching step S20 is conventionally conveying the long laminated film 100, or continuously unwinding the laminated film 100 from the film roll of the long laminated film 100, which can be carried out continuously while conveying. A guide roll etc. can be used for the conveyance system of a film.

積層膜100的延伸倍率,可依據所期望的偏光特性適當地選擇,較理想為對積層膜100的原本長度而言超出5倍且在17倍以下,更理想為超出5倍且在8倍以下。延伸倍率為5倍以下時,因聚乙烯醇系樹脂層6’無法充分配向,會有偏光片層5的偏光度無法充分變高的情形。另一方面,延伸倍率超出17倍時,容易產生延伸時膜的斷裂,同時延伸膜200的厚度變得比需要地薄,在後續步驟的加工性及處理性恐會降低。延伸處理,不限於一階段的延伸,可用多階段進行。 The elongation ratio of the laminated film 100 can be appropriately selected according to the desired polarizing characteristics, and it is preferably more than 5 times and not more than 17 times the original length of the laminated film 100, more preferably more than 5 times and not more than 8 times. . When the stretching ratio is less than 5 times, the degree of polarization of the polarizer layer 5 may not be sufficiently high because the polyvinyl alcohol-based resin layer 6' cannot be sufficiently aligned. On the other hand, when the stretching ratio exceeds 17 times, film breakage is likely to occur during stretching, and the thickness of the stretched film 200 becomes thinner than necessary, which may lower the workability and handling properties in subsequent steps. The elongation treatment is not limited to one-stage elongation, and may be performed in multiple stages.

延伸處理,除了可為對膜的長度方向(膜的傳送方向)進行延伸之縱向延伸,亦可為對膜的寬度方向延伸之橫向延伸或斜向延伸等。作為縱向延伸方式,例如使用輥延伸的輥間延伸、壓縮延伸、使用夾頭(chuck或夾具(clip))延伸等,作為橫向延伸方式,例如拉幅(Tenter)法等。延伸處理可採用潤濕式延伸方法、乾式延伸方法之任一種,使用乾式延伸方法,在延伸溫度可從寬的範圍選擇之點上較理想。 The stretching treatment may be not only longitudinal stretching that stretches the film in the longitudinal direction (film transport direction), but also transverse stretching or oblique stretching that stretches the film in the width direction. The longitudinal stretching method includes, for example, inter-roll stretching using roll stretching, compression stretching, and chuck (clip) stretching, and the like, and the transverse stretching method includes, for example, a tenter method. For the stretching treatment, either a wet stretching method or a dry stretching method can be used, and the dry stretching method is preferable because the stretching temperature can be selected from a wide range.

延伸溫度,係設定為聚乙烯醇系樹脂層6與基材膜30全部顯示可延伸程度的流動性之溫度以上,較理想為基材膜30的相轉移溫度(熔點或玻璃轉化溫度)的-30℃至+30℃的範圍,更理想為-30℃至+5℃的範圍,更加理想為-25℃至+0℃的範圍。基材膜30為複數樹脂層所構成時,上述相轉移溫度係指該複數樹脂層所示的相轉移溫度中最高的相轉移溫度。 The stretching temperature is set to be above the temperature at which both the polyvinyl alcohol-based resin layer 6 and the base film 30 exhibit extensible fluidity, preferably the phase transition temperature (melting point or glass transition temperature) of the base film 30 - The range of 30°C to +30°C, more preferably the range of -30°C to +5°C, more preferably the range of -25°C to +0°C. When the base film 30 is comprised by several resin layers, the said phase transition temperature means the highest phase transition temperature among the phase transition temperatures shown by this several resin layer.

延伸溫度低於相轉移溫度的-30℃時,難以達成超出5倍的高倍率延伸,或基材膜30的流動性太低,延伸處理有變困難的傾向。延伸溫度超出相轉移溫度的+30℃時,基材膜30的流動性太大,延伸有變困難的傾向。由於更容易達成超出5倍的高倍率延伸,延伸溫度為上述範圍內,更理想為120℃以上。 If the stretching temperature is lower than -30° C. which is the phase transition temperature, it may be difficult to achieve high-magnification stretching exceeding 5 times, or the fluidity of the base film 30 may be too low, and the stretching process may become difficult. When the stretching temperature exceeds +30° C. of the phase transition temperature, the fluidity of the base film 30 becomes too high, and stretching tends to become difficult. Since it is easier to achieve high-magnification extension exceeding 5 times, the extension temperature is within the above range, more preferably 120° C. or higher.

延伸處理之積層膜100的加熱方法,有區域加熱法(例如噴吹熱風調整至指定溫度的加熱爐之延伸區域內加熱的方法);使用輥延伸時,將輥本身進行加熱的 方法;加熱器加熱法(將紅外線加熱器、鹵素燈加熱器、板式加熱器等設置於積層膜100的上下並用輻射熱加熱的方法)等。輥間延伸方式,從延伸溫度的均勻性的觀點上,較理想為區域加熱法。 The heating method of the stretched laminated film 100 includes a regional heating method (for example, a method of heating in the stretching area of a heating furnace adjusted to a specified temperature by blowing hot air); a method of heating the roll itself when stretching with a roll; Heating method (a method of installing infrared heaters, halogen lamp heaters, plate heaters, etc. on the upper and lower sides of the laminated film 100 and heating with radiant heat), etc. The stretching method between rolls is preferably a zone heating method from the viewpoint of the uniformity of the stretching temperature.

延伸步驟S20前,亦可設置將積層膜100進行預熱的預熱處理步驟。作為預熱方法,可使用與延伸處理之加熱方法相同的方法。預熱溫度以延伸溫度的-50℃至±0℃的範圍較理想,延伸溫度的-40℃至-10℃的範圍更理想。 Before the stretching step S20, a preheating step of preheating the laminated film 100 may also be provided. As the preheating method, the same method as the heating method of the stretching treatment can be used. The preheating temperature is preferably in the range of -50°C to ±0°C of the extension temperature, and more preferably in the range of -40°C to -10°C of the extension temperature.

而且,延伸步驟S20之延伸處理後,可設置熱固定處理步驟。熱固定處理,係將延伸膜200的端部藉由夾具握持的狀態下,一邊維持緊張狀態,一邊在聚乙烯醇系樹脂的結晶化溫度以上進行熱處理之處理。藉由該熱固定處理,促進聚乙烯醇系樹脂層6’的結晶化。熱固定處理的溫度係以延伸溫度的-0℃至-80℃的範圍較理想,延伸溫度的-0℃至-50℃的範圍更理想。 Moreover, after the stretching process in the stretching step S20, a heat fixing process step may be provided. The heat setting treatment is a process of heat-treating at a temperature equal to or higher than the crystallization temperature of the polyvinyl alcohol-based resin while holding the end of the stretched film 200 with a jig and maintaining a tensioned state. Crystallization of the polyvinyl alcohol-based resin layer 6' is accelerated by this heat-fixing treatment. The temperature of the heat fixing treatment is preferably in the range of -0°C to -80°C of the stretching temperature, and more preferably in the range of -0°C to -50°C of the stretching temperature.

(3)染色步驟S30 (3) Dyeing step S30

本步驟,係將延伸膜200的聚乙烯醇系樹脂層6’用二色性色素的碘染色,使其吸附配向,形成染色層,得到基材膜30’及染色層所構成的染色積層膜之步驟。染色步驟S30,一般的情況下,係一邊傳送長條的延伸膜200,或從長條的延伸膜200的捲物的膜卷,連續地捲出延伸膜200,可將其傳送的同時連續進行。膜的傳送係可使用導輥等進行。 In this step, the polyvinyl alcohol-based resin layer 6' of the stretched film 200 is dyed with iodine of a dichroic dye to make it absorb and align to form a dyed layer, and obtain a dyed laminated film composed of the base film 30' and the dyed layer. the steps. The dyeing step S30, in general, is to convey the elongated stretched film 200, or roll out the stretched film 200 continuously from the film roll of the elongated stretched film 200, which can be carried out continuously while it is conveyed. . The transport system of the film can be performed using a guide roll or the like.

染色步驟S30係可藉由將延伸膜200浸漬於含有碘的溶液(染色浴)進行。作為染色浴,可使用碘溶解於溶劑之溶液。作為染色溶液的溶劑,一般係使用水,亦可再添加與水具有相溶性之有機溶劑。染色浴的碘的濃度,對溶劑100重量份而言,較理想為0.01至10重量份,更理想為0.02至7重量份。對染色浴的浸漬時間,使可得到所期望的視感度校正單體透過率(Ty)之方式,以對應染色浴中碘的濃度而調整較理想。 The dyeing step S30 can be performed by immersing the stretched film 200 in a solution (dyeing bath) containing iodine. As a dyeing bath, a solution of iodine dissolved in a solvent can be used. As the solvent of the dyeing solution, water is generally used, and an organic solvent compatible with water can also be added. The concentration of iodine in the dyeing bath is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 7 parts by weight, relative to 100 parts by weight of the solvent. It is ideal to adjust the immersion time of the dyeing bath to correspond to the concentration of iodine in the dyeing bath so that the desired sensitivity-corrected monomer transmittance (Ty) can be obtained.

含有碘的染色浴,由於可提高染色效率,故以進一步添加碘化物較理想。作為碘化物,例如碘化鉀、碘化鋰、碘化鈉、碘化鋅、碘化鋁、碘化鉛、碘化銅、碘化鋇、碘化鈣、碘化錫、碘化鈦等。染色浴的碘化物的濃度,對溶劑100重量份而言,較理想為0.01至20重量份。碘化物中,以添加碘化鉀較理想。添加碘化鉀時,碘與碘化鉀的比例,以重量比計,較理想為1:5至1:100的範圍,更理想為1:6至1:80的範圍。染色浴的溫度,較理想為10至60℃,更理想為20至40℃。 The dyeing bath containing iodine is ideal to further add iodide because the dyeing efficiency can be improved. Examples of iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide and the like. The concentration of iodide in the dyeing bath is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the solvent. Among the iodides, it is more desirable to add potassium iodide. When potassium iodide is added, the ratio of iodine to potassium iodide is preferably in the range of 1:5 to 1:100, more preferably in the range of 1:6 to 1:80 in terms of weight ratio. The temperature of the dyeing bath is preferably 10 to 60°C, more preferably 20 to 40°C.

再者,染色步驟S30中,對延伸膜200可再實施追加的延伸處理。作為該情況的實施態樣,例如1)於上述延伸步驟S20,進行比目標低的倍率之延伸處理後,染色步驟S30之染色處理中,進行延伸處理,使總延伸倍率成為目標的倍率的態樣;如後述於染色處理後進行交聯處理時,2)於上述延伸步驟S20,進行比目標低的倍率之延伸處理後,染色步驟S30之染色處理中,進行總延 伸倍率未達目標倍率程度的延伸處理,然後,在交聯處理中,進行最終的總延伸倍率成為目標的倍率的延伸處理的態樣等。 In addition, in the dyeing step S30 , an additional stretching process may be performed on the stretched film 200 . As an implementation aspect of this case, for example, 1) after stretching at a magnification lower than the target in the above-mentioned stretching step S20, stretching is performed in the dyeing process in the dyeing step S30 so that the total stretching magnification becomes the target magnification. When carrying out the cross-linking treatment after the dyeing treatment as described later, 2) in the above-mentioned elongation step S20, after performing the elongation treatment at a magnification lower than the target, in the dyeing treatment of the dyeing step S30, the total elongation magnification does not reach the target magnification level stretching treatment, and then, in the cross-linking treatment, a stretching treatment in which the final total stretching ratio becomes a target ratio is performed, and the like.

(4)交聯步驟S40 (4) Cross-linking step S40

本步驟,係將染色積層膜的染色層進行交聯,形成交聯層,得到基材膜30’及交聯層所構成的交聯積層膜之步驟。交聯步驟,係可藉由將染色積層膜浸漬於含有至少包含硼酸的交聯劑之交聯液進行。交聯步驟S40,一般的情況下,係一邊傳送長條的染色積層膜,或從長條的染色積層膜的捲物的膜卷,連續地捲出染色積層膜,可將其傳送的同時連續進行。膜的傳送,可使用導輥等進行。 This step is a step of cross-linking the dyed layer of the dyed laminated film to form a cross-linked layer to obtain a cross-linked laminated film composed of the base film 30' and the cross-linked layer. The cross-linking step can be performed by immersing the dyed laminated film in a cross-linking liquid containing a cross-linking agent containing at least boric acid. The cross-linking step S40, in general, is to convey the long strip of dyed laminated film, or continuously roll out the dyed laminated film from the film roll of the long strip of dyed laminated film, which can be conveyed continuously conduct. The conveyance of the film can be performed using guide rollers or the like.

交聯液,可為只含有硼酸作為交聯劑者,除了硼酸以外,亦可含有如硼砂的硼化合物、乙二醛、戊二醛等的其它交聯劑。其它交聯劑,可僅使用一種,亦可併用2種以上。 The cross-linking liquid may contain only boric acid as a cross-linking agent, and other cross-linking agents such as boron compounds such as borax, glyoxal, and glutaraldehyde may be contained in addition to boric acid. As for other crosslinking agents, one kind may be used alone, or two or more kinds may be used in combination.

作為交聯液,可使用硼酸溶解於溶劑的溶液。作為溶劑,可使用水,亦可再包含與水具有相溶性之有機溶劑。交聯液中的硼酸含量,對溶劑100重量份而言,較理想為1至20重量份,更理想為5至15重量份,硼酸以外的其它交聯劑的含量,對溶劑100重量份而言,較理想為1至20重量份,更理想為1至10重量份。 As the crosslinking solution, a solution obtained by dissolving boric acid in a solvent can be used. As the solvent, water may be used, and an organic solvent compatible with water may be further included. The content of boric acid in the crosslinking solution is preferably 1 to 20 parts by weight, more preferably 5 to 15 parts by weight, for 100 parts by weight of the solvent, and the content of other crosslinking agents other than boric acid is 100 parts by weight for the solvent. In other words, it is more preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight.

交聯液,可更包含碘化物。藉由碘化物的添加,可使染色層的面內的偏光特性更均一化。碘化物的具體例,係與上述相同。交聯液的碘化物的含量,對溶劑 100重量份而言,較理想為未達10重量份,更理想為8重量份以下,亦可為0重量份(亦可不包含碘化物)。交聯液的溫度的下限值,較理想為40℃以上,上限值,較理想為82℃以下。交聯液的溫度超出82℃時,染色層的聚乙烯醇系樹脂一部分溶出,染色後容易發生不均。 The cross-linking solution may further contain iodide. The in-plane polarization characteristics of the dyed layer can be made more uniform by the addition of iodide. Specific examples of iodide are the same as above. The content of iodide in the crosslinking liquid is preferably less than 10 parts by weight, more preferably 8 parts by weight or less, or 0 parts by weight (the iodide may not be included) with respect to 100 parts by weight of the solvent. The lower limit of the temperature of the crosslinking solution is preferably 40°C or higher, and the upper limit is preferably 82°C or lower. When the temperature of the cross-linking solution exceeds 82°C, part of the polyvinyl alcohol-based resin in the dyed layer is eluted, and unevenness is likely to occur after dyeing.

交聯處理,可藉由於染色浴中調配交聯劑,與染色處理同時進行。而且,亦可使用含組成不同的2種以上含交聯劑的溶液,進行2次以上浸漬於含交聯劑之溶液中的處理。藉由充分進行交聯處理,染色層中的硼含有率變大,可提高聚碘離子的錯合物的配向性。亦可在交聯處理中進行延伸處理。交聯處理中實施延伸處理的具體態樣,係如上述。 The cross-linking treatment can be carried out simultaneously with the dyeing treatment by preparing a cross-linking agent in the dyeing bath. Furthermore, two or more cross-linking agent-containing solutions having different compositions may be used, and the treatment of immersing in the cross-linking agent-containing solution may be performed two or more times. By sufficiently performing the cross-linking treatment, the boron content in the dyed layer increases, and the alignment of the polyiodide ion complex can be improved. Stretching treatment may also be performed during the crosslinking treatment. The specific aspects of carrying out the stretching treatment in the crosslinking treatment are as described above.

於交聯步驟S40,附加於染色積層膜的張力,對寬度方向的每單位長度,較理想為1N/cm以上,更理想為2N/cm以上,更加理想為5N/cm以上。張力的上限值無特別限制,較理想為30N/cm以下,更理想為20N/cm以下。於交聯步驟S40,使成為染色層的聚乙烯醇系樹脂的配向不緩和之方式,在染色積層膜的延伸方向上持續賦予張力較理想。 The tension applied to the dyed laminated film in the crosslinking step S40 is preferably 1 N/cm or more, more preferably 2 N/cm or more, and still more preferably 5 N/cm or more per unit length in the width direction. The upper limit of the tension is not particularly limited, but is preferably 30 N/cm or less, more preferably 20 N/cm or less. In the crosslinking step S40, it is desirable to continuously apply tension in the extending direction of the dyed laminated film so that the alignment of the polyvinyl alcohol-based resin used as the dyed layer is not eased.

例如,染色積層膜一邊用2個軋輥傳送,一邊浸漬於交聯槽內的交聯液,連續地進行交聯處理時,藉由調整送入側的軋輥的旋轉速度與送出側的軋輥的旋轉速度,可調整附加於染色積層膜的張力。 For example, when the dyed laminated film is conveyed by two rolls while being immersed in the cross-linking solution in the cross-linking tank, and the cross-linking process is continuously performed, by adjusting the rotation speed of the rolls on the feeding side and the rotation speed of the rolls on the sending side The speed can adjust the tension attached to the dyed laminated film.

(5)去硼步驟S50 (5) boron removal step S50

參考第4圖,本步驟係藉由使交聯積層膜的交聯層中所含的硼含有率降低,形成偏光片層5,得到基材膜30’及偏光片層5所成的偏光性積層膜300的步驟。去硼步驟S50,一般的情況下,係一邊傳送長條的交聯積層膜,或從長條的交聯積層膜的捲物的膜卷,連續地捲出交聯積層膜,可將其傳送的同時連續進行。膜的傳送,可使用導輥等進行。 With reference to Fig. 4, this step is to form the polarizer layer 5 by reducing the boron content contained in the crosslinked layer of the crosslinked laminated film, and obtain the polarizing properties formed by the base film 30' and the polarizer layer 5. The step of laminating film 300. The boron removal step S50, in general, is to convey the long strip of cross-linked laminated film, or continuously roll out the cross-linked laminated film from the film roll of the long strip of cross-linked laminated film, which can be sent simultaneously and continuously. The conveyance of the film can be performed using guide rollers or the like.

去硼步驟S50,可具備具有硼酸濃度低於交聯步驟S40所使用的交聯液的硼酸濃度之去硼液、及使與交聯積層膜的交聯層接觸的去硼液接觸步驟。去硼液接觸步驟,係可藉由將交聯積層膜浸漬於去硼液、並將交聯積層膜的交聯層以去硼液沖淋洗淨等進行。去硼液,可使用硼酸溶解於溶劑的溶液或不含硼酸的溶液。作為不含溶劑與硼酸的溶液,可使用水,亦可更包含與水具有相溶性的有機溶劑。去硼液的硼酸的含量,對溶劑的總重量,以未達10重量份較理想,更理想為8重量份以下,可為0.1重量份以上。 The boron-removing step S50 may include a boron-removing solution having a boric acid concentration lower than that of the crosslinking solution used in the crosslinking step S40, and a step of contacting the boron-removing solution with the crosslinked layer of the crosslinked laminated film. The step of contacting the boron-removing solution can be carried out by immersing the cross-linked laminated film in the boron-removing solution, and rinsing the cross-linked layer of the cross-linked laminated film with the boron-removing solution. As the boron removal solution, a solution in which boric acid is dissolved in a solvent or a solution without boric acid can be used. As the solution free of solvent and boric acid, water may be used, and an organic solvent compatible with water may be further included. The content of boric acid in the boron-removing solution is preferably less than 10 parts by weight, more preferably less than 8 parts by weight, and may be more than 0.1 parts by weight relative to the total weight of the solvent.

藉由進行使去硼液與交聯層接觸的處理,可除去交聯層所含的過多硼酸、配向性低的聚碘離子的錯合物。藉此,因偏光片層5所含的硼含有率降低,故偏光片層5(偏光膜)在加熱時的收縮力,可變小。而且,可提高偏光性積層膜300的偏光片層5的偏光度、透過率。 By performing the treatment of bringing the boron-removing solution into contact with the cross-linked layer, excess boric acid contained in the cross-linked layer and complexes of polyiodide ions with low orientation can be removed. Thereby, since the boron content rate contained in the polarizer layer 5 is reduced, the contraction force of the polarizer layer 5 (polarizing film) during heating can be reduced. Furthermore, the degree of polarization and the transmittance of the polarizer layer 5 of the polarizing laminated film 300 can be increased.

去硼液,亦可包含碘化物。碘化物的具體例,係與上述相同。去硼液之碘化物的含量,對溶劑的總 重量,較理想為15重量份以下,更理想為8重量份以下,5重量份以上較理想。藉由調整去硼液中的碘化物的含量,可調整所得之偏光性積層膜的色相。去硼液的溫度,較理想為70℃以下,更理想為65℃以下。而且,交聯液的溫度,以高於去硼液的溫度者較理想。 The boron removal solution may also contain iodide. Specific examples of iodide are the same as above. The content of the iodide in the boron-removing solution is preferably less than 15 parts by weight, more preferably less than 8 parts by weight, and more than 5 parts by weight, to the total weight of the solvent. By adjusting the content of iodide in the boron removal solution, the hue of the obtained polarizing laminated film can be adjusted. The temperature of the boron removal solution is preferably below 70°C, more preferably below 65°C. Moreover, the temperature of the cross-linking solution is ideally higher than that of the boron-removing solution.

藉由使用組成不同的2種以上的去硼液,可進行2次以上的去硼液接觸步驟。進行複數次的去硼液接觸步驟時,去硼液接觸步驟的處理方法,可為相同,亦可為不同。 By using two or more kinds of boron-removing liquids with different compositions, it is possible to perform two or more contact steps of boron-removing liquids. When carrying out multiple boron-removing liquid contact steps, the treatment methods of the boron-removing liquid contact steps can be the same or different.

於交聯步驟及去硼酸步驟,包含複數個以含硼酸的溶液進行處理的步驟時,相較於前段步驟,控制含硼酸的溶液的硼酸濃度低且附加於膜的張力變小之後段的全部步驟,成為去硼步驟。例如,硼酸濃度,可隨後段步驟的進展逐漸降低,硼酸濃度一旦降低,可保持固定,亦可為該等的組合。而且,附加於膜的張力,可隨後段步驟的進展逐漸降低,張力一旦降低,可保持固定,亦可為該等的組合。於後段步驟,使用與前段步驟的硼酸濃度相同的高硼酸濃度的溶液時,其後段步驟成為交聯步驟。 When the cross-linking step and the boric acid removal step include multiple steps of treating with a boric acid-containing solution, compared with the previous step, the boric acid concentration of the boric acid-containing solution is controlled to be low and the tension added to the membrane becomes smaller. The step becomes the boron removal step. For example, the concentration of boric acid can be gradually decreased with the progress of subsequent steps, once the concentration of boric acid is decreased, it can be kept constant, or a combination of these can also be used. Moreover, the tension added to the film can be gradually reduced as the subsequent steps progress, and once the tension is reduced, it can be kept constant, or it can be a combination of these. In the latter step, when a solution having the same high boric acid concentration as that of the former step is used, the latter step becomes a crosslinking step.

而且,交聯步驟為包含複數個以含硼酸的溶液進行處理的步驟時,相較於該複數個步驟中之任一步驟,控制硼酸濃度低且附加於膜的張力變小之後段的全部步驟,成為去硼步驟,去硼步驟,較理想為控制使硼酸濃度比交聯步驟的最後步驟低且附加於膜的張力變小。 Furthermore, when the cross-linking step includes a plurality of steps of treating with a boric acid-containing solution, compared with any one of the plurality of steps, the concentration of boric acid is controlled to be low and the tension applied to the membrane is reduced. , becomes the boron removal step, and the boron removal step is ideally controlled so that the concentration of boric acid is lower than that of the last step of the crosslinking step and the tension added to the membrane becomes smaller.

實施去硼步驟S50後,較理想為進行偏光 性積層膜的乾燥處理。進行該乾燥處理時,乾燥處理前所進行的浸漬於去硼液的處理,使用不含硼酸的去硼液,可防止偏光片層表面發生的缺陷而較理想。乾燥處理,可採用自然乾燥、送風乾燥、加熱乾燥等的任意適當的方法。例如於加熱乾燥時,乾燥溫度,通常可為20至95℃,乾燥時間,通常可為1至15分鐘。 After performing the boron removal step S50, it is preferable to dry the polarizing laminated film. When performing this drying treatment, it is preferable to use a boron-free solution that does not contain boric acid for the treatment of immersion in the boron-removing solution before the drying treatment, so as to prevent defects on the surface of the polarizer layer. For the drying treatment, any appropriate method such as natural drying, air drying, and heating drying can be adopted. For example, in heat drying, the drying temperature is usually 20 to 95° C., and the drying time is usually 1 to 15 minutes.

於去硼步驟S50的去硼液接觸步驟,附加於交聯積層膜的張力大小,以控制為小於交聯步驟S40之附加於染色積層膜的張力者較理想。藉此,可更有效地進行交聯層所含的過多硼酸、配向性低的聚碘離子的錯合物之去除,故可抑制偏光片層在加熱時之收縮力,可有效率地製造光學特性佳的偏光性積層膜。於去硼步驟S50,附加於交聯積層膜的張力,對寬度方向每單位長度,以未達16N/cm較理想,更理想為14N/cm以下。張力的下限值只要超出0N/cm即可,較理想為1N/cm。於去硼步驟S50,交聯積層膜以實質上不延伸者較理想。所謂實質上不延伸,係指延伸倍率為1.05倍以下。 In the boron-removing solution contact step of the boron-removing step S50, the tension added to the cross-linked laminated film is ideally controlled to be smaller than the tension added to the dyed laminated film in the cross-linked step S40. In this way, the excess boric acid contained in the cross-linked layer and the polyiodide ion complex with low alignment can be removed more effectively, so the shrinkage force of the polarizer layer during heating can be suppressed, and the optical fiber can be efficiently produced. Polarizing laminated film with excellent properties. In the boron removal step S50, the tension applied to the cross-linked laminated film is preferably less than 16 N/cm, more preferably 14 N/cm or less, per unit length in the width direction. The lower limit of the tension should just exceed 0 N/cm, and is preferably 1 N/cm. In the boron removal step S50, it is preferable that the cross-linked laminated film does not substantially extend. The term "substantially not stretched" means that the stretch ratio is 1.05 times or less.

與上述染色積層膜相同,交聯積層膜一邊用2個軋輥傳送,一邊進行去硼處理時,藉由調整送入側的軋輥的旋轉速度與送出側的軋輥的旋轉速度,可調整附加於交聯積層膜的張力。 Similar to the above-mentioned dyed laminated film, when the cross-linked laminated film is conveyed by two rollers while undergoing boron removal treatment, by adjusting the rotation speed of the rollers on the feeding side and the rotating speed of the rollers on the sending side, it is possible to adjust the amount added to the cross-linked laminated film. Tension of co-laminated membranes.

交聯積層膜的交聯層,係可藉由上述方法得到而薄膜化。於薄膜化的交聯層,於去硼步驟S50,以上述張力進行去硼處理時,可期待容易地除去交聯層所含 的過多硼酸、配向性低的聚碘離子的錯合物。所以,藉由上述製造方法所形成的偏光片層,不僅實現薄膜化,亦可提高光學特性,抑制收縮力的變大。 The crosslinked layer of the crosslinked laminated film can be obtained and thinned by the above method. In the thinned cross-linked layer, in the boron removal step S50, when the boron removal process is carried out with the above-mentioned tension, it can be expected that the complexes of excessive boric acid and polyiodide ions contained in the cross-linked layer can be easily removed. Therefore, the polarizer layer formed by the above manufacturing method not only achieves thinning, but also improves optical characteristics and suppresses the increase of shrinkage force.

〈偏光板的製造方法〉 <Manufacturing method of polarizing plate>

參考第1圖,本發明的偏光板的製造方法,依序包括以下步驟:於藉由上述方法所製造的偏光性積層膜的偏光片層之基材膜的相反側的面,貼合第1保護膜的第1保護膜貼合步驟S60;以及將基材膜剝離去除的剝離步驟S70。 With reference to Fig. 1, the manufacturing method of the polarizing plate of the present invention includes the following steps in sequence: on the opposite side of the substrate film of the polarizer layer of the polarizing laminated film manufactured by the above method, stick the first The first protective film lamination step S60 of the protective film; and the peeling step S70 of peeling and removing the base film.

經過第1保護膜貼合步驟S60及剝離步驟S70,得到第1保護膜10貼合於偏光片層5的一側的面之單面附保護膜之偏光板400(第5圖)。而且,如第1圖所示,剝離步驟S70後,設置第2保護膜貼合步驟S80,其係於藉由單面附保護膜之偏光板400之基材膜30’的剝離去除所露出的面(以下該面亦稱為「剝離面」),貼合第2保護膜20,可得到兩面附保護膜之偏光板2(第7圖)。 After the first protective film bonding step S60 and the peeling step S70, a polarizing plate 400 with a protective film on one side is obtained (FIG. 5 ) in which the first protective film 10 is bonded to one side of the polarizer layer 5 . Moreover, as shown in FIG. 1, after the peeling step S70, a second protective film bonding step S80 is provided, which is based on the peeling and removal of the base film 30' of the polarizing plate 400 with a protective film on one side. (hereinafter also referred to as "peeling surface"), the second protective film 20 is attached to obtain a polarizing plate 2 with protective films on both sides (Fig. 7).

(6)第1保護膜貼合步驟S60 (6) Step S60 of attaching the first protective film

參考第5圖,本步驟係偏光性積層膜300的與基材膜30’側相反側的面(亦即偏光片層5上),貼合第1保護膜10,得到多層膜400之步驟。第1保護膜10,係對應上述偏光板所具有的保護膜。第1保護膜貼合步驟S60,一般的情況下,係一邊傳送長條的偏光性積層膜300,或從長條的偏光性積層膜300的捲物的膜卷,連續地捲出偏光性 積層膜300,可將其傳送的同時連續進行。膜的傳送,可使用導輥等進行。 Referring to Fig. 5, this step is the step of laminating the first protective film 10 on the opposite side of the polarizing laminated film 300 to the base film 30' side (that is, on the polarizer layer 5) to obtain the multilayer film 400. The first protective film 10 corresponds to the protective film included in the above-mentioned polarizing plate. The first protective film bonding step S60, generally, is to continuously roll out the polarizing laminate while conveying the elongated polarizing laminate film 300, or from the film roll of the elongated polarizing laminate film 300 The film 300 can be carried out continuously while being conveyed. The conveyance of the film can be performed using guide rollers or the like.

偏光性積層膜300在基材膜30’的兩面具有偏光片層5時,通常於兩面的偏光片層5上,分別貼合第1保護膜10。於該情況,該等第1保護膜10,可為相同種的保護膜,亦可為不同種的保護膜。 When the polarizing laminated film 300 has polarizer layers 5 on both surfaces of the base film 30', the first protective films 10 are usually attached to the polarizer layers 5 on both surfaces, respectively. In this case, the first protective films 10 may be of the same type or of different types.

第1保護膜10可隔著第1接著劑層15,貼合於偏光片層5上。形成第1接著劑層15的接著劑,可為含有藉由如紫外線、可見光、電子束、X射線的活性能量線的照射而硬化的硬化性化合物之活性能量線硬化性接著劑(較理想為紫外線硬化性接著劑)、如聚乙烯醇系樹脂的接著劑成分溶解或分散於水的水系接著劑。 The first protective film 10 can be attached to the polarizer layer 5 via the first adhesive layer 15 . The adhesive forming the first adhesive layer 15 may be an active energy ray-curable adhesive (preferably UV-curable adhesives), water-based adhesives in which adhesive components such as polyvinyl alcohol-based resins are dissolved or dispersed in water.

使用活性能量線硬化性接著劑貼合第1保護膜10時,隔著成為第1接著劑層15的活性能量線硬化性接著劑,將第1保護膜10積層於偏光片層5上後,照射如紫外線、可見光、電子束、X射線的活性能量線,使接著劑層硬化。其中,以紫外線為宜,此時之光源,可使用低壓水銀燈、中壓水銀燈、高壓水銀燈、超高壓水銀燈、化學燈、黑光燈、微波激發水銀燈、金屬鹵素燈等。使用水系接著劑時,隔著水系接著劑將第1保護膜10積層於偏光片層5上後,使其加熱乾燥即可。 When laminating the first protective film 10 using an active energy ray-curable adhesive, the first protective film 10 is laminated on the polarizer layer 5 via the active energy ray-curable adhesive that becomes the first adhesive layer 15 , The adhesive layer is cured by irradiating active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Among them, ultraviolet light is suitable. As the light source at this time, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps can be used. When a water-based adhesive is used, the first protective film 10 is laminated on the polarizer layer 5 through the water-based adhesive, and then heated and dried.

第1保護膜10貼合於偏光片層5時,於第1保護膜10及/或偏光片層5的貼合面,為了提高與偏光片層5的接著性,可進行電漿處理、電暈處理、紫外線照 射處理、火焰(flame)處理、皂化處理等的表面處理(易接著處理),其中,以進行電漿處理、電暈處理或皂化處理較理想。 When the first protective film 10 is attached to the polarizer layer 5, in order to improve the adhesiveness with the polarizer layer 5 on the bonding surface of the first protective film 10 and/or the polarizer layer 5, plasma treatment, electric current, etc. can be carried out. Corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment and other surface treatment (adhesive treatment), among them, plasma treatment, corona treatment or saponification treatment is more ideal.

(第1保護膜) (1st protective film)

構成第1保護膜的材料,較理想為具有透光性(較理想為光學上透明)的熱塑性樹脂,作為如此的樹脂,例如鏈狀聚烯烴系樹脂(聚丙烯系樹脂等)、環狀聚烯烴系樹脂(降莰烯系樹脂等)之聚烯烴系樹脂;如纖維素三乙酸酯、纖維素二乙酸酯之纖維素酯系樹脂;聚酯系樹脂;聚碳酸酯系樹脂;(甲基)丙烯酸系樹脂;聚苯乙烯系樹脂;或該等的混合物、共聚物等所構成的膜。作為該等的熱塑性樹脂的具體例,例如構成上述基材膜30的熱塑性樹脂所說明者。 The material constituting the first protective film is preferably a thermoplastic resin having translucency (preferably optically transparent), and such resins include chain polyolefin resins (polypropylene resins, etc.), cyclic polyolefin resins, etc. Polyolefin-based resins of olefin-based resins (norcamphene-based resins, etc.); cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; polyester-based resins; polycarbonate-based resins; ( Meth)acrylic resin; polystyrene resin; or a film composed of a mixture or copolymer thereof. Specific examples of such thermoplastic resins include those described above for the thermoplastic resin constituting the base film 30 .

第1保護膜,可為合併具有如相位差膜、增亮膜的光學功能的保護膜。例如將由上述熱塑性樹脂所構成的膜進行延伸(一軸延伸或二軸延伸等),藉由於該膜上形成液晶層等,可成為賦予任意的相位差值之相位差膜。 The first protective film may be a protective film having combined optical functions such as a retardation film and a brightness enhancement film. For example, stretching (uniaxial stretching or biaxial stretching, etc.) a film made of the above-mentioned thermoplastic resin, and forming a liquid crystal layer etc. on the film can become a retardation film imparting an arbitrary retardation value.

亦可於第1保護膜10之與偏光片層5相反側的表面,形成硬塗層、防眩層、抗反射層、抗靜電層、防污層之表面處理層(塗覆層)。表面處理層,在實施第1保護膜貼合步驟S60前,可預先形成於第1保護膜10上,亦可在實施第1保護膜貼合步驟S60後或實施後述的剝離步驟S70後形成。而且,第1保護膜10,可含有1種或2種以上的如潤滑劑、塑化劑、分散劑、熱安定劑、紫外線吸收劑、紅外線吸收劑、抗靜電劑、抗氧化劑等的添加劑。 A surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer may also be formed on the surface of the first protective film 10 opposite to the polarizer layer 5 . The surface treatment layer may be preformed on the first protective film 10 before the first protective film bonding step S60, or may be formed after the first protective film bonding step S60 or the peeling step S70 described later. Furthermore, the first protective film 10 may contain one or more additives such as lubricants, plasticizers, dispersants, heat stabilizers, ultraviolet absorbers, infrared absorbers, antistatic agents, and antioxidants.

第1保護膜10的厚度,從偏光板的薄型化的觀點,較理想為90μm以下,更理想為50μm以下,更加理想為35μm以下,特別理想為30μm以下。第1保護膜10的厚度,從強度及處理性的觀點,通常為5μm以上。 The thickness of the first protective film 10 is preferably 90 μm or less, more preferably 50 μm or less, still more preferably 35 μm or less, particularly preferably 30 μm or less, from the viewpoint of thinning the polarizing plate. The thickness of the first protective film 10 is usually 5 μm or more from the viewpoint of strength and handleability.

(7)剝離步驟S70 (7) Stripping step S70

參考第6圖,本步驟係從多層膜400剝離去除基材膜30’而得到偏光板(單面附保護膜之偏光板)的步驟。偏光性積層膜300在基材膜30’的兩面具有偏光片層5,並將第1保護膜10貼合於該等二者的偏光片層5時,藉由該剝離步驟S70,從1片偏光性積層膜300,可得到2片單面附保護膜之偏光板1。剝離步驟S70,一般的情況下,係一邊傳送長條的多層膜400,或從長條的多層膜400的捲物的膜卷,連續地捲出多層膜400,可將其傳送的同時連續進行。膜的傳送,可使用導輥等進行。 Referring to FIG. 6, this step is a step of peeling and removing the base film 30' from the multilayer film 400 to obtain a polarizing plate (polarizing plate with a protective film on one side). When the polarizing laminated film 300 has the polarizer layer 5 on both surfaces of the base film 30', and the first protective film 10 is bonded to the polarizer layers 5 of the two, by this peeling step S70, from one sheet The polarizing laminated film 300 can be used to obtain two polarizing plates 1 with a protective film on one side. Peeling step S70, in general, is to convey the long multilayer film 400, or roll out the multilayer film 400 continuously from the film roll of the roll of the long multilayer film 400, which can be carried out continuously while it is conveyed. . The conveyance of the film can be performed using guide rollers or the like.

基材膜30’的剝離去除方法,並無特別限制,可用與通常附黏著劑的偏光板所進行的分隔片(剝離膜)的剝離步驟S70相同的方法剝離。基材膜30’,係在第1保護膜貼合步驟S60後,可直接立即剝離,亦可於第1保護膜貼合步驟S60後,一度捲成卷狀,在其後的步驟一邊捲出一邊剝離。 The method of peeling and removing the base film 30' is not particularly limited, and it can be peeled by the same method as the peeling step S70 of the separator (peeling film) usually performed on a polarizing plate with an adhesive. The base film 30' can be peeled off directly after the first protective film laminating step S60, or it can be rolled into a roll once after the first protective film laminating step S60, and rolled out in subsequent steps. Peel off one side.

如上述,第1保護膜貼合步驟S60所得之多層膜400,在基材膜30’的兩面分別積層偏光片層5及第1保護膜10,亦即可為具有第1保護膜10/偏光片層5/基材膜30’/偏光片層5/第1保護膜10(第1接著劑層15省略 描述)的層構成的膜。於該情況,經過2段的剝離步驟,從1片多層膜400得到2片單面附保護膜之偏光板1。於第1段的剝離步驟,從上述構成的多層膜400,剝離具有「第1保護膜10/偏光片層5/基材膜30’」的層構成的膜,得到單面附保護膜之偏光板1。於第2段的剝離步驟,從具有經剝離的「第1保護膜10/偏光片層5/基材膜30’」的層構成的膜,剝離基材膜30’,再得到單面附保護膜之偏光板1。 As mentioned above, the multilayer film 400 obtained in the step S60 of attaching the first protective film is laminated with the polarizer layer 5 and the first protective film 10 on both sides of the base film 30', that is, it can have the first protective film 10/polarizer A film composed of layers of sheet layer 5/substrate film 30'/polarizer layer 5/first protective film 10 (the description of the first adhesive layer 15 is omitted). In this case, two polarizing plates 1 with a protective film on one side are obtained from one multilayer film 400 through two peeling steps. In the peeling step of the first stage, from the multilayer film 400 of the above structure, the film having the layer composition of "first protective film 10/polarizer layer 5/substrate film 30'" is peeled off to obtain polarized light with a protective film on one side. plate 1. In the peeling step of the second stage, the substrate film 30' is peeled off from the film having the peeled "first protective film 10/polarizer layer 5/substrate film 30'" layer, and then a single-sided protective film is obtained. Film polarizer 1.

(8)第2保護膜貼合步驟S80 (8) Second protective film bonding step S80

參考第7圖,本步驟係於單面附保護膜之偏光板1的偏光片層5上,貼合第2保護膜20,得到兩面附保護膜之偏光板2之任意步驟。第2保護膜貼合步驟S80,一般的情況下,係一邊傳送長條的單面附保護膜之偏光板1,或從長條的單面附保護膜之偏光板1的捲物的膜卷,連續地捲出單面附保護膜之偏光板1,可將其傳送的同時連續進行。膜的傳送,可使用導輥等進行。 Referring to Fig. 7, this step is an arbitrary step of attaching the second protective film 20 on the polarizer layer 5 of the polarizer 1 with a protective film on one side to obtain a polarizer 2 with protective films on both sides. The second protective film sticking step S80, in general, is to convey the long polarizing plate 1 with a protective film on one side, or the film roll from the roll of the long polarizing plate 1 with a protective film on one side , Continuously roll out the polarizing plate 1 with a protective film on one side, which can be carried out continuously while conveying it. The conveyance of the film can be performed using guide rollers or the like.

第2保護膜20係可隔著第2接著劑層25貼合於偏光片層5上。關於第2保護膜20及第2接著劑層25的構成、材質以及第2保護膜20的貼合方法,分別引用關於第1保護膜10及第1接著劑層15以及第1保護膜10的貼合方法之記載。第1保護膜10與第2保護膜20,可互為相同種類的保護膜,亦可為不同種類的保護膜。第1接著劑層15與第2接著劑層25,可由互為相同種類的接著劑形成,亦可由不同種類的接著劑形成。 The second protective film 20 can be attached to the polarizer layer 5 via the second adhesive layer 25 . Regarding the composition and material of the second protective film 20 and the second adhesive layer 25, and the bonding method of the second protective film 20, references are made to the articles on the first protective film 10, the first adhesive layer 15, and the first protective film 10, respectively. Records of lamination methods. The first protective film 10 and the second protective film 20 may be the same type of protective film or different types of protective films. The first adhesive layer 15 and the second adhesive layer 25 may be formed of the same type of adhesive or may be formed of different types of adhesives.

[實施例] [Example]

以下,顯示實施例及比較例,更具體地說明本發明,但本發明不限於該等例。 Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these examples.

[視感度校正單體透過率(Ty)及視感度校正偏光度(Py)] [Sensitivity Corrected Single Transmittance (Ty) and Sensitivity Corrected Polarization Degree (Py)]

對各偏光性積層膜,使用附積分球的分光光度計(日本分光(股)製「V7100」),測定波長380至780nm的範圍之平行透過率與垂直透過率,根據下述式:單體透過率(%)=(平行透過率+垂直透過率)/2 For each polarizing laminated film, use a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Corporation) to measure the parallel transmittance and vertical transmittance in the wavelength range from 380 to 780 nm, according to the following formula: Monomer Transmittance (%)=(parallel transmittance + vertical transmittance)/2

偏光度(%)={(平行透過率-垂直透過率)/(平行透過率+垂直透過率)}×100 Degree of polarization (%)={(parallel transmittance-vertical transmittance)/(parallel transmittance+vertical transmittance)}×100

算出各波長之單體透過率及偏光度。測定時,使從偏光性積層膜的成為偏光片層側入射光,偏光性積層膜的基材膜側為偵測器側。再者,基材膜因充分透明,在偏光性積層膜測定的光學特性與只測定偏光性積層膜的偏光片層(偏光膜)時的光學特性之間,無差異,在偏光性積層膜測定的光學特性的值,係可視為只有對偏光片層(偏光膜)測定光學特性時的值。 Calculate the single transmittance and polarization degree of each wavelength. In the measurement, light is incident from the polarizer layer side of the polarizing laminated film, and the base film side of the polarizing laminated film is the detector side. Furthermore, because the base film is sufficiently transparent, there is no difference between the optical characteristics measured by the polarizing laminated film and the optical characteristics when only the polarizer layer (polarizing film) of the polarizing laminated film is measured. The value of the optical characteristic of , can be regarded as the value when the optical characteristic is measured only for the polarizer layer (polarizing film).

此處,所謂「平行透過率」,係指從格蘭-湯姆森稜鏡射出的偏光的方向與偏光膜試料的透過軸平行時的透過率。而且,所謂「垂直透過率」,係指從格蘭-湯姆森稜鏡射出的偏光的方向與偏光膜試料的透過軸垂直時的透過率。 Here, the "parallel transmittance" refers to the transmittance when the direction of the polarized light emitted from the Glan-Thomson's is parallel to the transmission axis of the polarizing film sample. In addition, the term "vertical transmittance" refers to the transmittance when the direction of the polarized light emitted from the Glan-Thomson Plasma is perpendicular to the transmission axis of the polarizing film sample.

對於所得之單體透過率及偏光度,藉由JIS Z 8701:1999「顏色的表示方法-XYZ表色系及X10Y10Z10 表色系」的2度視角(C光源),進行視感度校正,求得視感度校正單體透過率(Ty)及視感度校正偏光度(Py)。 For the obtained single transmittance and polarization degree, the viewing angle is 2 degrees (C light source) by JIS Z 8701: 1999 "Expression method of color - XYZ color system and X 10 Y 10 Z 10 color system" Sensitivity correction, get the sensitivity correction monomer transmittance (Ty) and the sensitivity correction polarization degree (Py).

[波長475nm的平行吸光度/垂直吸光度所表示的比] [The ratio expressed by the parallel absorbance/perpendicular absorbance at a wavelength of 475nm]

如上述測定的波長475nm的平行透過率及垂直透過率,根據下述式:吸光度=-log10(T/T0);分別換算為平行吸光度及垂直吸光度。上述式中,T0為入射偏光性積層膜的從格蘭-湯姆森稜鏡射出的波長475nm的偏光的光強度,T為波長475nm的平行透過率或垂直透過率。 The parallel transmittance and vertical transmittance measured at a wavelength of 475 nm as described above are converted into parallel absorbance and vertical absorbance respectively according to the following formula: absorbance=-log 10 (T/T 0 ). In the above formula, T 0 is the light intensity of polarized light with a wavelength of 475nm emitted from the Glan-Thomson ellipse entering the polarizing multilayer film, and T is the parallel transmittance or vertical transmittance at a wavelength of 475nm.

[硼含有率的測定] [Measurement of boron content]

從偏光性積層膜剝離去除基材膜所得之偏光片層(偏光膜)0.2g浸漬於溫度95℃的熱水100mL 60分鐘,完全溶解後,添加甘露醇水溶液(12.5重量%)30g,成為測定用樣品溶液。該測定用樣品溶液在到達中和點為止,滴入氫氧化鈉水溶液(1莫耳/升)。從該滴入量,根據下述式:硼含有率(重量%)=1.08×氫氧化鈉水溶液滴入量(mL)/偏光膜的重量(g) 0.2 g of the polarizer layer (polarizing film) obtained by peeling and removing the substrate film from the polarizing laminated film was immersed in 100 mL of hot water at a temperature of 95°C for 60 minutes, and after it was completely dissolved, 30 g of mannitol aqueous solution (12.5% by weight) was added to obtain the measurement. with sample solution. A sodium hydroxide aqueous solution (1 mol/liter) was added dropwise to the measurement sample solution until it reached the neutralization point. From this dropping amount, according to the following formula: boron content rate (weight %)=1.08×sodium hydroxide aqueous solution dropping amount (mL)/weight of polarizing film (g)

算出聚乙烯醇系樹脂膜中的硼含有率(重量%)。以相同的順序,對從去硼步驟前的交聯積層膜剝離去除基材膜所得之交聯層,算出硼含有率,確認去硼步驟前後的硼含有率的變化。 The boron content (% by weight) in the polyvinyl alcohol-based resin film was calculated. In the same procedure, the boron content was calculated for the crosslinked layer obtained by peeling and removing the base film from the crosslinked laminated film before the boron removal step, and the change in the boron content before and after the boron removal step was confirmed.

[收縮力的測定] [Measurement of contraction force]

從偏光性積層膜,切取吸收軸方向(延伸方向)作為長邊的寬度2mm、長度8mm的試料,剝離去除基材膜,得到偏光片層(偏光膜)的測定用試料,將測定用試料的厚度,使用接觸式膜厚計(商品名“DIGIMICRO MH-15M”Nikon(股)製)測定。將該測定用試料設置於熱機械分析裝置(Thermo-Mechanical Analyzer:TMA)「EXSTAR-6000」(SII Nanotechnology(股)製),尺寸保持不變,測定在80℃保持240分鐘時發生的長邊方向(吸收軸方向、延伸方向)的收縮力(實測收縮力)。將測定的實測收縮力除以實測的測定用試料的厚度之後,乘以5μm,成為寬度2mm、每5μm厚度之收縮力[N/5μm](下式)。 From the polarizing laminated film, a sample with a width of 2 mm and a length of 8 mm in the direction of the absorption axis (extension direction) is cut out, and the substrate film is peeled off to obtain a sample for measurement of the polarizer layer (polarizing film). The thickness was measured using a contact-type film thickness meter (trade name "DIGIMICRO MH-15M" manufactured by Nikon Co., Ltd.). This measurement sample was set in a thermomechanical analyzer (Thermo-Mechanical Analyzer: TMA) "EXSTAR-6000" (manufactured by SII Nanotechnology Co., Ltd.), and the long side that occurred when the size was kept at 80°C for 240 minutes was measured. The contraction force (measured contraction force) in the direction (absorption axis direction, extension direction). Divide the measured shrinkage force by the measured thickness of the measurement sample, and multiply by 5 μm to obtain the shrinkage force [N/5 μm] per 5 μm thickness with a width of 2 mm (the following formula).

收縮力[N/5μm]=(偏光片層(偏光膜)的實測收縮力[N])/(偏光片層(偏光膜)的厚度(實測值)[μm])×5 Contraction force [N/5μm]=(measured shrinkage force of polarizer layer (polarizer film) [N])/(thickness of polarizer layer (polarizer film) (measured value)[μm])×5

〔實施例1〕 [Example 1]

(底塗層形成步驟) (undercoat layer forming step)

將聚乙烯醇粉末(日本合成化學工業(股)製「Z-200」、平均聚合度1100、平均皂化度99.5莫耳%)溶解於95℃的熱水,調製濃度3重量%的聚乙烯醇水溶液。於所得之水溶液,混合對聚乙烯醇粉末6重量份為5重量份的比例之交聯劑(田岡化學工業(股)製「SUMIREZ RESIN 650」),得到底塗層形成用塗佈液。 Polyvinyl alcohol powder ("Z-200" manufactured by Nippon Gosei Chemical Industry Co., Ltd., average degree of polymerization 1100, average degree of saponification 99.5 mole%) was dissolved in hot water at 95°C to prepare polyvinyl alcohol with a concentration of 3% by weight aqueous solution. The resulting aqueous solution was mixed with a crosslinking agent (Sumirez Resin 650 manufactured by Taoka Chemical Industry Co., Ltd.) at a ratio of 5 parts by weight to 6 parts by weight of polyvinyl alcohol powder to obtain a coating solution for forming an undercoat layer.

然後,將厚度90μm的基材膜(未延伸聚丙烯膜、熔點:163℃)一邊連續地傳送,於其單面實施電暈處理後,於其電暈處理面,使用微凹版塗佈機,連續地塗 佈上述底塗層形成用塗佈液,藉由80℃、10分鐘的乾燥,形成厚度0.2μm之底塗層。 Next, a substrate film (unstretched polypropylene film, melting point: 163° C.) with a thickness of 90 μm was continuously conveyed, and after corona treatment was performed on one side thereof, a micro-gravure coater was used on the corona-treated side, The above-mentioned coating liquid for forming an undercoat layer was continuously applied, and dried at 80° C. for 10 minutes to form an undercoat layer having a thickness of 0.2 μm.

(積層膜的製作(樹脂層形成步驟)) (Preparation of laminated film (resin layer formation step))

將聚乙烯醇粉末(可樂麗(股)製「PVA124」、平均聚合度2400、皂化度98.0至99.0莫耳%)溶解於95℃的熱水,調製濃度7.5重量%的聚乙烯醇水溶液,將其作為聚乙烯醇系樹脂層形成用塗佈液。 Polyvinyl alcohol powder (“PVA124” manufactured by Kuraray Co., Ltd., average degree of polymerization 2400, saponification degree 98.0 to 99.0 mole%) was dissolved in hot water at 95°C to prepare a polyvinyl alcohol aqueous solution with a concentration of 7.5% by weight. This is used as a coating liquid for forming a polyvinyl alcohol-based resin layer.

於上述底塗層形成步驟製作的具有底塗層的基材膜一邊連續地傳送,於其底塗層表面,使用模塗機,連續地塗佈上述聚乙烯醇系樹脂層形成用塗佈液後,藉由在80至90℃使其乾燥,於底塗層上形成膜厚9μm之聚乙烯醇系樹脂層,得到基材膜/底塗層/聚乙烯醇系樹脂層所構成的積層膜。 The substrate film having the undercoat layer produced in the above undercoat layer forming step is continuously conveyed, and the above-mentioned coating liquid for forming a polyvinyl alcohol-based resin layer is continuously coated on the surface of the undercoat layer using a die coater. Afterwards, by drying at 80 to 90°C, a polyvinyl alcohol-based resin layer with a film thickness of 9 μm is formed on the primer layer to obtain a laminated film consisting of base film/primer layer/polyvinyl alcohol-based resin layer .

(延伸步驟) (extended steps)

對上述積層膜一邊連續地傳送,使用浮動的縱向單軸延伸裝置,延伸時的最高溫度為150℃下,實施5.3倍的自由端單軸延伸(空中延伸),得到延伸膜。延伸後的聚乙烯醇系樹脂層的厚度為5μm。 The above-mentioned laminated film was conveyed continuously, using a floating longitudinal uniaxial stretching device, and the maximum temperature during stretching was 150° C., and 5.3 times free-end uniaxial stretching (in-air stretching) was performed to obtain a stretched film. The thickness of the stretched polyvinyl alcohol-based resin layer was 5 μm.

(染色步驟) (Dyeing step)

將上述延伸膜一邊連續地傳送,連續地浸漬於包含碘與碘化鉀之30℃的染色浴(對每100重量份之水,包含碘0.35重量份、碘化鉀5.0重量份),滯留時間約為90秒,進行聚乙烯醇系樹脂層的染色處理,得到染色積層膜。 While continuously conveying the above stretched film, it is continuously immersed in a 30°C dyeing bath containing iodine and potassium iodide (containing 0.35 parts by weight of iodine and 5.0 parts by weight of potassium iodide per 100 parts by weight of water), and the residence time is about 90 seconds. , the dyeing treatment of the polyvinyl alcohol-based resin layer is performed to obtain a dyed laminated film.

(交聯步驟) (cross-linking step)

將上述染色積層膜一邊連續地傳送,連續地浸漬於包含硼酸之78℃的交聯液(對每100重量份之水,包含硼酸10.4重量份),張力16N/cm,滯留時間約為120秒,進行交聯處理,得到交聯積層膜。 Continuously convey the above-mentioned dyed laminated film, and continuously immerse it in a 78°C cross-linking solution containing boric acid (10.4 parts by weight of boric acid per 100 parts by weight of water), with a tension of 16N/cm and a residence time of about 120 seconds , and carry out cross-linking treatment to obtain a cross-linked laminated film.

(去硼步驟) (removal of boron step)

然後,將上述交聯積層膜一邊連續地傳送,連續地浸漬於包含硼酸及碘化鉀之65℃的去硼液(對每100重量份之水,包含硼酸2重量份及碘化鉀6.0重量份),張力1N/cm,滯留時間約為60秒,進行去硼處理。然後,以張力1N/cm,浸漬於7℃的水中5秒,進行去硼處理,使用鼓風機,去除附著於兩面的液體,在60℃下使其乾燥,得到基材膜上具有厚度5μm的偏光片層的偏光性積層膜。 Then, while the above-mentioned cross-linked laminated film is continuously conveyed, it is continuously immersed in a 65°C boron-removing solution containing boric acid and potassium iodide (for every 100 parts by weight of water, 2 parts by weight of boric acid and 6.0 parts by weight of potassium iodide are included), and the tension 1N/cm, the residence time is about 60 seconds, and the boron removal treatment is carried out. Then, immerse in water at 7°C for 5 seconds with a tension of 1N/cm, perform boron removal treatment, use a blower to remove the liquid adhering to both sides, and dry it at 60°C to obtain a polarized film with a thickness of 5 μm on the substrate film. Sheet polarizing laminated film.

從所得之偏光性積層膜,如上述「評價用樣品的製作」之記載,得到評價樣品,算出視感度校正單體透過率(Ty)、視感度校正偏光度(Py)、收縮力、評價用樣品的硼含有率,檢查去硼步驟前後的硼含有率的變化。其結果表示於表1。表1中,硼含有率的變化的欄之「減少」,係指去硼步驟後的硼含有率比去硼步驟前的硼含有率小。 From the obtained polarizing laminated film, evaluation samples were obtained as described in the above "Preparation of Evaluation Samples", and the sensitivity-corrected single transmittance (Ty), sensitivity-corrected polarization degree (Py), shrinkage force, and evaluation parameters were calculated. The boron content of the sample is checked for changes in the boron content before and after the boron removal step. The results are shown in Table 1. In Table 1, "decrease" in the column of change in boron content rate means that the boron content rate after the boron removal step is smaller than the boron content rate before the boron removal step.

〔實施例2〕 [Example 2]

去硼步驟中,張力為5N/cm以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。結果表示於表1。 In the boron removal step, the same operation as in Example 1 was performed except that the tension was 5 N/cm to obtain a polarizing laminated film, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

〔實施例3〕 [Example 3]

去硼步驟中,除了硼酸為5重量份以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。 In the boron-removing step, the same operation as in Example 1 was performed except that boric acid was 5 parts by weight to obtain a polarizing laminated film, and the same evaluation as in Example 1 was performed.

〔實施例4〕 [Example 4]

去硼步驟中,除了硼酸為5重量份,張力為5N/cm以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。 In the boron removal step, except that the boric acid was 5 parts by weight and the tension was 5 N/cm, the same operation as in Example 1 was carried out to obtain a polarizing laminated film, and the same evaluation was performed as in Example 1.

〔實施例5〕 [Example 5]

去硼步驟中,除了硼酸為5重量份,張力為10N/cm以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。 In the boron removal step, except that the boric acid was 5 parts by weight and the tension was 10 N/cm, the same operation as in Example 1 was carried out to obtain a polarizing laminated film, and the evaluation was performed in the same manner as in Example 1.

〔比較例1〕 [Comparative Example 1]

去硼步驟中,除了張力為16N/cm以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。 In the boron removal step, the same operation as in Example 1 was performed except that the tension was 16 N/cm to obtain a polarizing laminated film, and the same evaluation as in Example 1 was performed.

〔比較例2〕 [Comparative Example 2]

去硼步驟中,除了硼酸為3.5重量份,張力為16N/cm以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。 In the boron removal step, the same operation as in Example 1 was carried out except that the boric acid was 3.5 parts by weight and the tension was 16 N/cm, to obtain a polarizing laminated film, and the same evaluation as in Example 1 was performed.

〔比較例3〕 [Comparative Example 3]

去硼步驟中,除了硼酸為5重量份,張力為16N/cm以外,進行與實施例1之相同操作,得到偏光性積層膜,與實施例1進行相同評價。 In the boron-removing step, the same operation as in Example 1 was performed except that the boric acid was 5 parts by weight and the tension was 16 N/cm, to obtain a polarizing laminated film, and the same evaluation was performed as in Example 1.

Figure 106141161-A0202-12-0040-1
Figure 106141161-A0202-12-0040-1

如表1所示,實施例1至5所得之偏光性積層膜的偏光層(偏光膜),係硼含有率為2.5重量%以上且在4.1重量%以下,視感度校正單體透過率(Ty)超出40.5%,波長475nm的平行吸光度/垂直吸光度所表示的比未達0.022。而且,實施例1至5的偏光層(偏光膜),視感度校正單體透過率(Ty)為41.5時之視感度校正偏光度(Py)超出99.994。實施例1至5的偏光層(偏光膜)的長邊方向(吸收軸方向、延伸方向)的收縮力控制在未達1.77N/5μm。 As shown in Table 1, the polarizing layer (polarizing film) of the polarizing laminated film obtained in Examples 1 to 5 has a boron content of not less than 2.5% by weight and not more than 4.1% by weight, and the single transmittance (Ty ) exceeds 40.5%, and the ratio represented by the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm does not reach 0.022. Furthermore, the polarizing layer (polarizing film) of Examples 1 to 5 has a sensitivity-corrected polarization degree (Py) exceeding 99.994 when the sensitivity-corrected single transmittance (Ty) is 41.5. The shrinkage force in the longitudinal direction (absorption axis direction, stretching direction) of the polarizing layer (polarizing film) of Examples 1 to 5 was controlled to be less than 1.77 N/5 μm.

於比較例1至3,視感度校正單體透過率(Ty)為41.5時之視感度校正偏光度(Py)為低。此係推測於去硼步驟中,附加於交聯積層膜的張力的大小,係在交聯步驟,與附加於染色積層膜的張力的大小相同。而且,於比較例1至3,波長475nm的平行吸光度/垂直吸光度所表示的比為大。實施例1至5及比較例1至3中,去硼步驟前後的硼含有率減少,推測係在去硼步驟中,交聯層所含的過多硼酸被去除,而在比較例1至3,於去硼步驟中,並未充分去除配向性低的聚碘離子的錯合物。 In Comparative Examples 1 to 3, the sensitivity-corrected polarization degree (Py) was low when the sensitivity-corrected single transmittance (Ty) was 41.5. It is speculated that the magnitude of the tension added to the cross-linked laminated film in the boron-removing step is the same as the magnitude of the tension added to the dyed laminated film in the cross-linked step. Furthermore, in Comparative Examples 1 to 3, the ratio represented by the parallel absorbance/perpendicular absorbance at a wavelength of 475 nm was large. In Examples 1 to 5 and Comparative Examples 1 to 3, the boron content before and after the boron removal step decreases. It is speculated that in the boron removal step, the excessive boric acid contained in the cross-linked layer is removed, while in Comparative Examples 1 to 3, In the boron-removing step, the polyiodide ion complexes with low alignment were not sufficiently removed.

Claims (4)

一種偏光膜,其係碘配向於聚乙烯醇系樹脂層的偏光膜;硼含有率為2.5重量%以上未達3.0重量%;視感度校正單體透過率(Ty)超出40.5%;波長475nm的平行吸光度/垂直吸光度所表示的比未達0.022;在80℃下保持4小時時之吸收軸方向的寬度為2mm、每5μm厚度的收縮力未達1.77N/5μm;厚度為10μm以下。 A polarizing film, which is a polarizing film in which iodine is aligned to a polyvinyl alcohol-based resin layer; the boron content rate is not less than 2.5% by weight and not more than 3.0% by weight; the transmittance (Ty) of a single light sensitivity correction exceeds 40.5%; the wavelength is 475nm The ratio of parallel absorbance/perpendicular absorbance is less than 0.022; when kept at 80°C for 4 hours, the width in the direction of the absorption axis is 2mm, and the shrinkage force per 5μm thickness is less than 1.77N/5μm; the thickness is less than 10μm. 一種偏光板,其係於申請專利範圍第1項所述之偏光膜的至少一側的面,具有保護膜。 A polarizing plate, which is provided with a protective film on at least one side of the polarizing film described in item 1 of the scope of the patent application. 一種偏光性積層膜的製造方法,依序具備:在基材膜的至少一側的面形成聚乙烯醇系樹脂層而得到積層膜之樹脂層形成步驟;將前述積層膜延伸而得到延伸膜之延伸步驟;藉由將前述延伸膜的前述聚乙烯醇系樹脂層以碘染色,形成染色層而得到染色積層膜的染色步驟;藉由將前述染色積層膜的前述染色層以包含硼酸的交聯液交聯,形成交聯層而得到交聯積層膜的交聯步驟;以及藉由降低前述交聯積層膜的前述交聯層所包含的硼含有率,形成硼含有率為2.5重量%以上未達3.0重量%的偏光片層而得到由基材膜及申請專利範圍第1 或2項所述之偏光膜所成的偏光性積層膜的去硼步驟;其中前述去硼步驟具有前述交聯層與去硼液接觸之去硼液接觸步驟,前述去硼液具有比前述交聯液的硼酸濃度低的硼酸濃度;於前述去硼液接觸步驟,以小於前述交聯步驟中附加於附前述染色層的積層膜的張力的大小的方式,控制附加於前述交聯積層膜的張力的大小。 A method for producing a polarizing laminated film comprising, in order: forming a resin layer forming a polyvinyl alcohol-based resin layer on at least one surface of a base film to obtain a laminated film; stretching the laminated film to obtain a stretched film stretching step; a dyeing step of obtaining a dyed laminated film by dyeing the polyvinyl alcohol-based resin layer of the stretched film with iodine to form a dyed layer; crosslinking the dyed layer of the dyed laminated film with boric acid liquid cross-linking, forming a cross-linked layer to obtain a cross-linked laminated film; Up to 3.0% by weight of the polarizer layer is obtained from the base film and the patent application scope No. 1 Or the boron removal step of the polarizing laminated film formed by the polarizing film described in item 2; wherein the aforementioned boron removal step has the step of contacting the aforementioned cross-linked layer with the boron removal liquid, and the aforementioned boron removal liquid has a higher ratio than the aforementioned cross-linked boron removal step. The low boric acid concentration of the boric acid concentration of the linking solution; in the aforementioned contact step of the boron-removing solution, the amount of tension added to the aforementioned cross-linked laminated film is controlled in a manner that is smaller than the tension of the laminated film attached to the aforementioned dyed layer in the aforementioned cross-linking step. The size of the tension. 一種偏光板的製造方法,依序包括:藉由申請專利範圍第3項所述的製造方法,製造偏光性積層膜的步驟;於前述偏光片層之與前述基材膜的相反側的面,貼合保護膜的步驟;以及剝離去除前述基材膜的步驟。 A method for manufacturing a polarizing plate, comprising sequentially: using the manufacturing method described in claim 3 of the scope of the patent application, the step of manufacturing a polarizing laminated film; on the surface of the polarizer layer opposite to the substrate film, a step of attaching a protective film; and a step of peeling and removing the aforementioned base film.
TW106141161A 2016-12-02 2017-11-27 Polarizing film and method for producing polarizing laminzted film TWI795379B (en)

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