Polarizer for inhibiting bluing of polarizers and preparation method thereof

Abstract

The invention discloses a polaroid for inhibiting bluing of polarizers and a preparation method of the polaroid. The polaroid comprises a PVA (polyvinyl alcohol) polarizers layer, an outer inner protective layer and an inner protective layer, wherein the outer inner protective layer and the inner protective layer are attached to the upper surface and the lower surface of the PVA polarizers layer. And the outer inner protection layer and the inner inner protection layer are bonded with the PVA polarized photon layer through the high-barrier UV adhesive layer. A surface barrier layer is arranged outside the outer inner protective layer, and a protective film is bonded outside the surface barrier layer; a release film is attached to the surface of the inner protection layer through a PSA adhesive layer, and light absorber microcapsules used for absorbing blue light are added into the PSA adhesive layer. The surface blocking layer of the polaroid is located on the outermost layer of the polaroid, invasion of near water vapor is intercepted for the first time, the high-blocking UV adhesive layers are tightly attached to the two sides of the PVA polaroid, water vapor can be prevented from invading the PVA polaroid layer again, light absorbent microcapsules in the PSA adhesive layers release light absorbents within 2 h under the conditions that the temperature is 60 DEG C and the humidity is 90%, blue light is absorbed, and the light absorption effect is good. Through the triple protection, the hue stability of the polaroid is ensured when the polaroid is influenced by temperature and humidity.

Description

Technical Field

[0001] This invention relates to a polarizer that suppresses blue emission from polarizers and its preparation method, belonging to the field of polarizer technology. Background Technology

[0002] A polarizer is an optical device used to polarize natural light or arbitrarily polarized light in a specific direction. The basic structure of a polarizer includes a central PVA polarizer (polyvinyl alcohol dyed and crossed extended film), flanked by two PVA protective layers: an outer protective layer and an inner protective layer. The PVA polarizer is responsible for polarization. The PVA polarizer film is prepared from a PVA base film through steps such as swelling, dyeing, crossing, stretching, washing, fixing, and drying. However, PVA polarizers are easily affected by the external environment. To protect the physical properties of the polarizing film, a thin optical film with high light transmittance, good water resistance, and a certain mechanical strength is typically laminated to both sides of the PVA as a PVA protective layer, forming the polarizer core. Depending on the application requirements, a pressure-sensitive adhesive (PSA) of a certain thickness is coated on the inner protective layer side, and a release film protecting the PSA is laminated on top. A surface protective film is then applied to the outer protective layer side as needed, resulting in a semi-finished polarizer. The semi-finished polarizing film is then slit and cut into sheets, and the edges are ground to obtain the finished polarizing film.

[0003] PVA polarizers contain a fixed proportion of I3. - and I5 - It serves to polarize light. Polarizers are easily affected by ambient temperature and humidity. Moisture entering the PVA polarizer layer can cause I3. - PVA photons dissolve in water and depolarize; heating PVA photons can promote I5. - Decomposed into I3 - I2 evaporates and depolarizes the polarizer. Depolarization of the polarizer affects its color rendering, and depending on the environmental factors of heat and humidity, I5... - Decomposing a multi-polarizer will result in a reddish tint, I3 - Decomposing multiple polarizers results in a bluer color. How to improve the influence of the environment on the color rendering of polarizers has been a problem that researchers have been continuously studying in recent years.

[0004] Chinese patent CN201811622900.4 discloses a polarizer with blue light suppression and moisture resistance functions and its preparation method. The polarizer includes, from top to bottom, a protective film, an upper TAC layer, an adhesive, a PVA layer, an adhesive, a lower TAC layer, a PSA adhesive, and a release film. The PVA layer absorbs or adheres with blue light suppressing absorbers and weather-resistant agents after color fixing. By adding an absorption process between the PVA color fixing and drying processes, the blue light absorbers and weather-resistant agents are adsorbed or adhered to the gaps in the PVA layer, giving the polarizer blue light suppression function and better moisture resistance. However, it is difficult for the blue light absorbers and weather-resistant agents to be adsorbed or adhered only to the gaps in the PVA layer; they are often also distributed in the direction perpendicular to the gaps in the PVA layer. This reduces the transmittance of the polarizer, making it difficult to achieve a transmittance of over 43%.

[0005] Chinese patent CN201810366247.3 discloses a method for preparing a blue light blocking polarizer. The blue light blocking polarizer mainly achieves the effect of absorbing blue light by adding a blue light blocking agent to the pressure-sensitive adhesive layer of the polarizer. The pressure-sensitive adhesive layer is composed of the following components by weight: 10%~30% acrylate resin, 60%~90% ethyl acetate, 0.1%~0.8% isocyanate crosslinking agent, 0.1%~0.8% epoxy crosslinking agent, 0.3%~1.5% silane coupling agent 1, 0.05%~0.5% silane coupling agent 2, and 0.3%~1.3% blue light blocking agent. After the above materials are mixed evenly, they are coated onto a release film to form a pressure-sensitive adhesive. This adhesive is then bonded to the original polarizer plate to produce an anti-blue light polarizer. The polarizer described in this invention has the effect of reducing blue light transmittance, and exhibits excellent moisture resistance, durability, and high-temperature resistance, as well as particularly good stability. However, this patent does not disclose the composition of the anti-blue light additives, and its test conditions involve placing the polarizer in a programmable temperature and humidity chamber at 90°C and 95% humidity for 20 hours, testing the change rate of its blue light transmittance. It does not provide test data for 500 hours, 750 hours, and 1000 hours at 60°C and 90% humidity, making it impossible to determine its color rendering effect and transmittance changes over long periods.

[0006] Therefore, how to suppress the blueing of polarizers caused by prolonged high temperature and humidity has become an urgent problem to be solved. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a polarizer that suppresses blue emission from polarizers and its preparation method.

[0008] The technical solution adopted by this invention to solve its technical problem is: A polarizer for suppressing blue light emission from polarizers includes a PVA polarizer layer, an outer inner protective layer and an inner inner protective layer adhered to the upper and lower surfaces of the PVA polarizer layer, a protective film bonded to the outside of the outer inner protective layer, and a release film bonded to the surface of the inner inner protective layer via a PSA adhesive layer; both the outer inner protective layer and the inner inner protective layer are bonded to the PVA polarizer layer via a high-barrier UV adhesive layer; a surface barrier layer is also provided between the outside of the outer inner protective layer and the protective film, and microcapsules of light absorbers for absorbing blue light are added to the PSA adhesive layer.

[0009] A further improvement of the present invention is that the high-barrier UV adhesive layer is obtained by mixing 15-25 parts by weight of CELLOXIDE2021P, 1-8 parts by weight of EPOLEAD GT401, 20-50 parts by weight of PLACACCEL M, 10-30 parts by weight of Kyoei EPOLIGHT 100MF, and 3-8 parts by weight of thioonium salt photoinitiator UVI-6976.

[0010] The thickness of the high-barrier UV adhesive layer is 2~4μm.

[0011] A further improvement of the present invention is that the surface barrier layer is formed by UV curing initiated by 10-25 parts by weight of phenolic epoxy acrylate, 10-25 parts by weight of Daicel EPOLEAD GT401, 20-30 parts by weight of trimethylolpropane triacrylate, and 15-25 parts by weight of pentaerythritol tetraacrylate, using 2-5 parts by weight of free radical initiator 184 (1-hydroxycyclohexylphenyl ketone) and 0.5-2.0 parts by weight of cationic initiator IGM Omnicat 320.

[0012] The thickness of the surface barrier layer is 4~10μm.

[0013] A further improvement of the present invention is that the capsule wall of the light absorber microcapsule is made of polyvinyl alcohol or dextrin, and the capsule wall ruptures and the light absorber escapes after 2 hours at a temperature of 60°C and a humidity of 90%.

[0014] The light absorber is a blue-violet and ultraviolet light absorber that has significant absorption in the 260~450nm range.

[0015] The size of the light absorber microcapsules is 200nm~600nm, and the microcapsule wall thickness is 100~300nm; the amount of light absorber microcapsules added is 0.1%~1.3% of the dry weight of the PSA adhesive layer.

[0016] A method for preparing a polarizer that suppresses blue emission from polarizers includes the following steps: S1. Formulation of light-absorbing PSA adhesive S11. Using acrylate raw gum as the main agent, a PSA colloidal composition with a solid content of 17-20% is prepared. S12. Add the light absorber microcapsules to the above PSA colloidal composition at a ratio of 0.1~1.3% of the dry weight of the PSA adhesive, stir evenly and set aside for use. S2. Preparation of high-barrier UV adhesive 15-25 parts by weight of CELLOXIDE 2021P, 1-8 parts by weight of EPOLEAD GT401, 20-50 parts by weight of PLACACCEL M, 10-30 parts by weight of Kyoei EPOLIGHT 100MF, and 3-8 parts by weight of thioonium salt photoinitiator UVI-6976 are mixed evenly to obtain a high-barrier UV adhesive. S3. Preparation of the outer original film with a surface barrier layer 10-25 parts by weight of phenolic epoxy acrylate, 10-25 parts by weight of Daicel EPOLEAD GT401, 20-30 parts by weight of TMPTA (trimethylolpropane triacrylate), 15-25 parts by weight of pentaerythritol tetraacrylate, 2-5 parts by weight of free radical initiator 184 (1-hydroxycyclohexylphenyl ketone), and 0.5-2.0 parts by weight of cationic initiator IGMOMmnicat320 are stirred and mixed evenly, and then applied to one surface of the outer original film. After curing by ultraviolet irradiation, the outer original film with a surface barrier layer is obtained. S4. Preparation of polarizer S41. The PVA film is unwound at the first unwinding point, and then subjected to swelling, dyeing, bridging, stretching, washing, color fixing and drying to obtain a PVA polarizer. Inner protective layers are bonded to the upper and lower surfaces of the PVA polarizer with high-barrier UV adhesive. The outer layer is called the outer inner protective layer, and the non-bonded surface has a high-barrier surface coating. The other inner protective layer opposite to the outer inner protective layer is called the inner inner protective layer. S42. Unwind the release film at the second unwinding point, apply PSA adhesive containing light absorber, dry it in a drying oven, and then attach it to the inner protective layer. S43. Unwind the protective film at the third unwinding point, attach it to the inner protective layer of the outer layer, and then rewind to obtain the polarizer semi-finished product. S44. The semi-finished polarizing film is unwound at the cutting line, and then cut and edge-grinding is performed to obtain the finished sheet polarizing film.

[0017] In step S3, the inner protective layer of the outer layer is a PMMA film or a PET film; the ultraviolet light (UVA) used for curing reaches 500 mJ / cm. 2 Above, and UVB reaches 500 mJ / cm2 above; In step S41, after bonding the outer and inner protective layers to the PVA polarizer surface using high-barrier UV adhesive, double-sided UV irradiation is used for curing, achieving a UVB intensity of 500 mJ / cm². 2 above.

[0018] The beneficial effects of this invention are: This invention provides a polarizer that suppresses the blue tint of polarizers by employing a triple protection mechanism to stabilize the polarizer's hue. The first mechanism is a surface barrier layer, located on the outermost layer of the polarizer, which initially blocks the intrusion of near-moisture. The second mechanism is a high-barrier UV adhesive layer, which adheres tightly to both sides of the PVA polarizer layer, further preventing moisture from penetrating the PVA polarizer layer and also preventing I2 from evaporating and releasing PVA polarizers, thus ensuring the hue stability of the polarizer under the influence of ambient temperature and humidity. The third mechanism is light-absorbing microcapsules. Several light-absorbing microcapsules contained in the PSA adhesive layer exhibit significant absorption in the 260-450 nm range. Under humid conditions, the capsule walls of these microcapsules rupture, releasing the light absorber to absorb blue-violet light, thereby suppressing the blue tint of polarizers. By employing the above two methods of moisture barrier and light absorption, the color stability of the polarizer is ensured under normal and high temperature and humidity conditions, and the polarizers do not turn blue. At the same time, because it also absorbs ultraviolet light, when the polarizer is applied to the LCD panel, ultraviolet light damage to the liquid crystal is avoided. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the polarizer structure of the present invention; In the diagram: 1. PVA polarizing layer; 2. High-barrier UV adhesive layer; 3. Inner protective layer; 4. Outer protective layer; 5. PSA adhesive layer; 6. Release film; 7. Surface barrier layer; 8. Protective film; 9. Light absorber microcapsules. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings.

[0021] The directions or similar terms used throughout this invention, such as "front," "back," "left," "right," "top," "bottom," "inner," "outer," and "side," are mainly for reference to the directions in the accompanying drawings. These directions or similar terms are only used to assist in explaining and understanding the embodiments of this invention and are not intended to limit this invention.

[0022] A polarizer that suppresses the blue bias of polarized photons, such as Figure 1As shown, it includes a PVA polarizer layer, an outer inner protective layer, and an inner inner protective layer bonded to the upper and lower surfaces of the PVA polarizer layer. Both the outer and inner inner protective layers are bonded to the PVA polarizer layer via a high-barrier UV adhesive layer. A surface barrier layer is provided outside the outer inner protective layer, and a protective film is bonded to the outside of the surface barrier layer. A release film is bonded to the surface of the inner inner protective layer via a PSA adhesive layer, and microcapsules containing blue light absorbers are added to the PSA adhesive layer.

[0023] In the polarizer that suppresses the blue bias of polarizers, the outer inner protective layer is a PMMA film or a PET film; the inner inner protective layer is a PMMA film, a COP film, or a SANUQI film.

[0024] In the polarizer that suppresses the blue bias of polarizers, the high-barrier UV adhesive layer is prepared by mixing 15-25 parts by weight of CELLOXIDE 2021P, 1-8 parts by weight of EPOLEAD GT401, 20-50 parts by weight of PLACACCEL M, 10-30 parts by weight of Kyoei EPOLIGHT 100MF, and 3-8 parts by weight of thioonium salt photoinitiator UVI-6976.

[0025] Furthermore, the thickness of the high-barrier UV adhesive layer is 2~4μm, preferably 3μm.

[0026] The high-barrier UV adhesive layer and inner protective layer both exhibit a water vapor permeability of 10~60 g / m² at 40℃ and 90% humidity. 2 ·24h.

[0027] In the polarizer that suppresses the blue bias of polarizers, the surface barrier layer is formed by UV curing initiated by 10-25 parts by weight of phenolic epoxy acrylate, 10-25 parts by weight of Daicel EPOLEAD GT401, 20-30 parts by weight of TMPTA (trimethylolpropane triacrylate), and 15-25 parts by weight of pentaerythritol tetraacrylate, using 2-5 parts by weight of free radical initiator 184 (1-hydroxycyclohexylphenyl ketone) and 0.5-2.0 parts by weight of cationic initiator IGM Omnicat 320.

[0028] Furthermore, the thickness of the surface barrier layer is 4~10μm, preferably 5~8μm.

[0029] The surface barrier layer and the outer inner protective layer both exhibit a water vapor permeability of 5~55 g / m² at 40℃ and 90% humidity. 2 ·24h.

[0030] In the polarizer that suppresses blue light from polarizers, light-absorbing microcapsules are added to the PSA adhesive layer. The capsule walls of the light-absorbing microcapsules can rupture under specific humidity conditions, and the core material light-absorbing agent in the microcapsules can be used to absorb blue light from the polarizer caused by humidity.

[0031] Furthermore, the light absorber is a blue-violet and ultraviolet light absorber with significant absorption in the 260-450 nm range. Even further, the light absorber is any one or a mixture of several of the following: benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, visible light absorber VIS400, and visible light absorber VIS427.

[0032] The capsule wall of the light absorber microcapsule can be made of polyvinyl alcohol or dextrin. The capsule wall ruptures after 2 hours at 60°C and 90% humidity, releasing the encapsulated light absorber and achieving absorption of polarized blue light. It should be noted that the capsule wall does not necessarily require 60°C and 90% humidity to rupture; rupture will also occur if the temperature and humidity are not met, but sufficient time is provided. The aforementioned condition of rupture after 2 hours at 60°C and 90% humidity is only a quantitative limitation on the capsule wall performance.

[0033] Furthermore, the size of the light absorber microcapsules is 200nm~600nm, and the microcapsule wall thickness is 100~300nm.

[0034] In the polarizer that suppresses the blue bias of polarizers, the amount of light absorber microcapsules added is 0.1~1.3% of the dry weight of the PSA adhesive layer.

[0035] In the polarizer that suppresses the blue bias of polarizers, the thickness of the PSA adhesive layer is 10~30μm, and the surface resistivity is 9.9×10⁻⁶. 11 Below Ω.

[0036] The composition of the PSA adhesive layer is not an inventive point of this invention. As long as it can satisfy the adhesion between the inner protective layer and the release film and does not react with the capsule wall of the light absorber microcapsule at room temperature, it is acceptable. No detailed limitation is made here.

[0037] Preferably, the PSA adhesive layer comprises acrylate raw gum, isocyanate crosslinking agent, epoxy compound, silane coupling agent, antistatic agent, and ethyl acetate.

[0038] More preferably, the acrylate adhesive is TD-227 adhesive produced by Jiangxi Taylai Polymer Materials Co., Ltd., the isocyanate crosslinking agent is TD-75 crosslinking agent produced by Zongyan Chemical Co., Ltd., the epoxy compound is E-5CM compound produced by Zongyan Chemical Co., Ltd., the silane coupling agent is A-50 coupling agent produced by Zongyan Chemical Co., Ltd., and the antistatic agent is YL-1001A antistatic agent produced by Yuanli New Materials (Hefei) Co., Ltd.

[0039] The method for preparing the polarizer that suppresses the blue polarization of polarizers includes the following steps: S1. Formulation of PSA adhesive containing light-absorbing microcapsules S11. Using 800-1000 parts by weight of acrylate raw gum as the main agent, add 0.2-1.8 parts by weight of isocyanate crosslinking agent, 0-1.0 parts by weight of epoxy compound, 0.4-2.0 parts by weight of silane coupling agent, 3.0-8.0 parts by weight of antistatic agent, and 150-180 parts by weight of ethyl acetate. Stir evenly to prepare a PSA colloidal composition with a solid content of 17-20%, and defoam before use. The weight-average molecular weight of the acrylate raw gum is 1.2 million to 2.5 million.

[0040] S12. Add the light absorber microcapsules to the above PSA colloidal composition at a ratio of 0.1~1.3% of the dry weight of the PSA adhesive, stir evenly and set aside for use.

[0041] The dry weight of the PSA adhesive is obtained by multiplying the weight of the PSA colloidal composition by its solid content.

[0042] S2. Preparation of high-barrier UV adhesive 15-25 parts by weight of CELLOXIDE 2021P, 1-8 parts by weight of EPOLEAD GT401, 20-50 parts by weight of PLACACCEL M, 10-30 parts by weight of Kyoei EPOLIGHT 100MF, and 3-8 parts by weight of thioonium salt photoinitiator UVI-6976 are mixed evenly to obtain a high-barrier UV adhesive.

[0043] S3. Preparation of the outer original film with a surface barrier layer 10-25 parts by weight of phenolic epoxy acrylate, 10-25 parts by weight of Daicel EPOLEAD GT401, 20-30 parts by weight of TMPTA (trimethylolpropane triacrylate), 15-25 parts by weight of pentaerythritol tetraacrylate, 2-5 parts by weight of free radical initiator 184 (1-hydroxycyclohexylphenyl ketone), and 0.5-2.0 parts by weight of cationic initiator IGMOMmnicat320 are stirred and mixed evenly, and then applied to one surface of the outer original film. After curing by ultraviolet irradiation, the outer original film with a surface barrier layer is obtained.

[0044] The inner protective layer of the outer layer is a PMMA film or a PET film; the ultraviolet A light used for curing reaches 500 mJ / cm. 2 Above, and UVB reaches 500 mJ / cm 2 above.

[0045] S4. Preparation of polarizer S41. The PVA film is unwound at the first unwinding point, and then subjected to swelling, dyeing, bridging, stretching, washing, color fixing and drying to obtain a PVA polarizer. Inner protective layers are bonded to the upper and lower surfaces of the PVA polarizer with high-barrier UV adhesive. The outer layer is called the outer inner protective layer, and the non-bonded surface has a high-barrier surface coating. The other inner protective layer opposite to the outer inner protective layer is called the inner inner protective layer. S42. Unwind the release film at the second unwinding point, apply PSA adhesive containing light absorber, dry it in a drying oven, and then attach it to the inner protective layer. S43. Unwind the protective film at the third unwinding point, attach it to the inner protective layer of the outer layer, and then rewind to obtain the polarizer semi-finished product. S44. The semi-finished polarizing film is unwound at the cutting line, and then cut and edge-grinding is performed to obtain the finished sheet polarizing film.

[0046] In step S41, after bonding the outer and inner protective layers to the PVA polarizer surface using high-barrier UV adhesive, double-sided UV irradiation is used for curing, with the UVB light reaching 500 mJ / cm². 2 above.

[0047] The present invention will be further described below with reference to embodiments and comparative examples.

[0048] In the following embodiments, all raw materials used are commercially available conventional products, and unless otherwise specified, no detailed restrictions are placed on their manufacturers. Example 1

[0049] A polarizer that suppresses the blue bias of polarized photons, such as Figure 1As shown, the device includes a PVA polarizing layer, an outer inner protective layer, and an inner inner protective layer bonded to the upper and lower surfaces of the PVA polarizing layer. Both the outer and inner inner protective layers are bonded to the PVA polarizing layer using a high-barrier UV adhesive layer. A surface barrier layer is provided outside the outer inner protective layer, and a protective film is bonded to the outside of the surface barrier layer. A release film is bonded to the surface of the inner protective layer using a PSA adhesive layer, and light-absorbing microcapsules are added to the PSA adhesive layer.

[0050] The polarizer that suppresses the blue polarization of polarizers is prepared by the following steps: S1. Formulation of light-absorbing PSA adhesive The PSA adhesive formula is as follows: Acrylic ester raw rubber base (Taylai TD-227) 1000 parts by weight Isocyanate crosslinking agent (Zongyan TD-75) 0.35 parts by weight Epoxy compounds (E-5CM) 0.68 parts by weight Silane coupling agent (Zongyan A-50) 0.73 parts by weight Antistatic agent (Yuanli YL-1001A) 3.0 parts by weight Ethyl acetate 170 parts by weight S11. Mix the acrylate raw gum and ethyl acetate evenly, add the remaining isocyanate crosslinking agent, epoxy compound, silane coupling agent and antistatic agent and mix thoroughly to obtain a PSA colloidal composition with a solid content of 18%, and defoam for later use. S12. Take 2.69 parts by weight of the light absorber VIS680 microcapsules and add them to 1176 parts by weight of the PSA colloidal composition. Stir well and set aside. The weight of the light absorber accounts for 1.27% of the dry weight of the PSA adhesive.

[0051] The light absorber VIS427 microcapsules are 400 nm in size, and the capsule wall material is polyvinyl alcohol with a wall thickness of 150 nm.

[0052] S2. Preparation of high-barrier UV adhesive 20 parts by weight of CELLOXIDE 2021P, 5 parts by weight of EPOLEAD GT401, 40 parts by weight of PLACACCEL M, 20 parts by weight of Kyoei EPOLIGHT 100MF, and 6 parts by weight of thioonium salt photoinitiator UVI-6976 were mixed evenly to obtain a high-barrier UV adhesive.

[0053] S3. Preparation of the outer original film with a surface barrier layer 20 parts by weight of phenolic epoxy acrylate, 10 parts by weight of Daicel EPOLEAD GT401, 30 parts by weight of TMPTA (trimethylolpropane triacrylate), 25 parts by weight of pentaerythritol tetraacrylate, 4 parts by weight of free radical initiator 184 (1-hydroxycyclohexylphenyl ketone), and 0.5 parts by weight of cationic initiator IGM Omnicat 320 were mixed evenly and applied to the non-primer surface of the PMMA base film. The mixture was then cured under ultraviolet light to obtain the outer base film with a surface barrier layer. The thickness of the surface barrier layer was 8 μm.

[0054] The ultraviolet light UVA is 520 mJ / cm. 2 UVB is 520 mJ / cm 2 .

[0055] S4. Preparation of polarizer S41. Unwind the PVA film at the first unwinding point, and perform swelling, dyeing, bridging, stretching, washing, color fixing and drying to obtain PVA polarizers; use high-barrier UV adhesive to bond PMMA inner protective layers to the upper and lower surfaces of the PVA polarizers respectively, the outer layer is the outer inner protective layer, the non-bonded surface has a high-barrier surface coating, and the other inner protective layer opposite to the outer inner protective layer is the inner inner protective layer. After the outer and inner protective layers are bonded together, the high-barrier UV adhesive needs to be cured by double-sided ultraviolet irradiation with a UVB intensity of 512 mJ / cm². 2 above.

[0056] The thickness of the high-barrier UV adhesive layer is 3 μm.

[0057] S42. Unwind the release film at the second unwinding point, apply PSA adhesive containing light absorber, dry it in a drying oven, and then attach it to the outer surface of the inner protective layer PMMA. S43. Unwind the protective film at the third unwinding point, attach it to the inner protective layer of the outer layer, and then rewind to obtain the polarizer semi-finished product. S44. The semi-finished polarizing film is unwound at the cutting line, and then cut and edge-grinding is performed to obtain the finished sheet polarizing film. Example 2

[0058] The structure and preparation method of the polarizer in this embodiment are basically the same as those in Example 1, except that the thicknesses of the surface barrier layer and the high-barrier UV adhesive layer are different. In this embodiment, the thickness of the surface barrier layer is 4 μm, and the thickness of the high-barrier UV adhesive layer is 2 μm. Example 3

[0059] The structure and preparation method of the polarizer in this embodiment are basically the same as those in Example 1, except that the content of the light absorber microcapsules in the PSA adhesive is different. In this embodiment, the light absorber microcapsules account for 1.0% of the dry weight of the PSA adhesive. Example 4

[0060] The structure and preparation method of the polarizer in this embodiment are basically the same as those in Example 1, except that the solid content of the PSA colloidal composition without added light-absorbing microcapsules is different. In this embodiment, the solid content of the PSA colloidal composition is 20%. Comparative Example 1

[0061] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the thickness of the surface barrier layer is different.

[0062] The thickness of the barrier layer on the surface of the polarizer in this comparative example is 3.5 μm, which is below the specified range. Comparative Example 2

[0063] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the thickness of the high-barrier UV adhesive layer is different.

[0064] The thickness of the high-barrier UV adhesive layer on the polarizer in this comparative example is 1.5 μm, which is below the specified range. Comparative Example 3

[0065] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the amount of Daicel EPOLEAD GT401 surface barrier layer added is different.

[0066] The comparative polarizer showed an addition of 28 parts by weight of Daicel EPOLEAD GT401 as a surface barrier layer, which is higher than the specified range. Comparative Example 4

[0067] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the amount of Daicel EPOLEAD GT401 surface barrier layer added is different.

[0068] The amount of Daicel EPOLEAD GT401 added to the surface barrier layer of the polarizer in this comparative example is 8 parts, which is below the limit value. Comparative Example 5

[0069] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the amount of high-barrier UV adhesive layer Daicel EPOLEAD GT401 added is different.

[0070] The amount of Daicel EPOLEAD GT401 added to the high-barrier UV adhesive layer of the polarizer in this comparative example is 9 parts, which is higher than the limit value. Comparative Example 6

[0071] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the amount of high-barrier UV adhesive layer nano-diameter EPOLEAD GT401 added is different.

[0072] The amount of Daicel EPOLEAD GT401 added to the high-barrier UV adhesive layer of the polarizer in this comparative example is 0.5 parts, which is below the limit value. Comparative Example 7

[0073] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the PSA adhesive layer in this comparative example does not contain light absorber microcapsules. Comparative Example 8

[0074] This comparative example is the comparative example of Example 1. The structure and preparation method of the polarizer in this comparative example are basically the same as those in Example 1. The only difference is that the content of light absorber microcapsules in the PSA adhesive layer is different.

[0075] In this comparative example, the microcapsules of the polarizer in the polarizer accounted for 1.8% of the weight of the PSA dry gel, which is higher than the limit value.

[0076] The components of Examples 1 to 4 and Comparative Examples 1 to 8 are shown in the table below.

[0077]

[0078] The polarizer products prepared in Examples 1-4 and Comparative Examples 1-8 were subjected to performance testing. The performance testing standards included: Hue: Place the polarizing film onto the panel and immerse it in a high temperature and humidity chamber at 60℃ and 90%RH for 500h, 750h, and 1000h. Remove it and let it stand at room temperature for 2h. Then turn on the power and illuminate the panel. Observe the panel color with the naked eye from different angles.

[0079] Transmittance: Tested using a Jasco V-7100 UV-Vis-NIR spectrophotometer.

[0080] Polarization: measured using a Jasco V-7100 UV-Vis-NIR spectrophotometer.

[0081] Table 1. Performance test table of polarizers prepared in the examples and comparative examples.

[0082] As can be seen from the data in the table, the polarizers of this application shown in Examples 1 to 4 have stable hue in a high temperature and humidity environment. They still maintain normal color and do not turn blue after 1000 hours at 60°C and 90% humidity, effectively solving the problem of polarizers turning blue easily in a high temperature and humidity environment. At the same time, the polarizers of this application have moderate transmittance and high polarization, and have excellent performance.

[0083] In Comparative Example 1, the thickness of the surface barrier layer is less than the minimum value within the specified range. This increases the moisture permeability of the surface barrier layer plus the outer inner protective layer, resulting in a decrease in the heat and moisture insulation effect of the surface barrier layer. Experimental data shows that when the polarizer-made panel is placed in a 60℃, 90%RH high-temperature and high-humidity chamber for 500h and 750h, the panel's hue remains normal. This demonstrates that even though the heat and moisture insulation effect of the surface barrier layer deteriorates, the high-barrier UV adhesive layer and the PSA adhesive layer containing light-absorbing microcapsules still possess certain heat and moisture insulation and blue-inhibiting effects. When the polarizer is placed in the high-humidity and high-temperature chamber for 1000h, the heat and moisture insulation effect of Comparative Example 1 is insufficient, and moisture entering the PVA polarizer layer will cause I... 3- Dissolves in water and degrades, although I 3- The decomposition of the microcapsules reduces their absorption of blue light. Even after the microcapsules rupture under humid heat and release the blue light absorber, they cannot absorb all the blue light, resulting in a bluish tint on the polarizer. Similarly, in Comparative Example 2, the thickness of the high-barrier UV adhesive layer was less than the minimum specified range. This increased the moisture permeability of the high-barrier UV adhesive layer and the inner protective layer, reducing the heat and moisture insulation effect. When the polarizer-made panel was placed in a 60℃, 90%RH high-temperature and high-humidity chamber for 500h and 750h, the panel's hue remained normal, but a bluish tint appeared after 1000h.

[0084] Comparative Examples 3 and 4 investigated the effect of the amount of Daicel EPOLEAD GT401 added to the surface barrier layer on the performance of the polarizer. In Comparative Example 3, the excessive amount of Daicel EPOLEAD GT401 in the surface barrier layer resulted in excessively high viscosity of the coating solution and poor applicability. In Comparative Example 4, the insufficient amount of Daicel EPOLEAD GT401 in the coating solution resulted in moderate viscosity and good applicability, but the barrier properties of the surface barrier layer decreased and the moisture permeability increased. The polarizer panel, after being placed in a 60℃, 90%RH high-temperature and high-humidity chamber for 1000 hours, exhibited a bluing phenomenon.

[0085] Comparative Examples 5 and 6 investigated the effect of the amount of Daicel EPOLEAD GT401 added to the high-barrier UV adhesive layer on the performance of the polarizer. In Comparative Example 5, the amount of Daicel EPOLEAD GT401 added to the high-barrier UV adhesive was too high, resulting in excessive viscosity of the high-barrier UV adhesive coating liquid and poor applicability. In Comparative Example 6, the amount of Daicel EPOLEAD GT401 added to the high-barrier UV adhesive was too low. Although the viscosity was moderate and the applicability was good, the UV adhesive barrier properties were reduced and the moisture permeability was increased. The polarizer panel made from this material showed a bluing phenomenon after being placed in a 60℃, 90%RH high-temperature and high-humidity chamber for 1000 hours.

[0086] Comparative Examples 7 and 8 investigated the performance of polarizers based on the light-absorbing PSA adhesive layer. Comparative Example 7's PSA adhesive did not contain any light-absorbing microcapsules, essentially relying on only two layers of heat and moisture insulation: a surface insulating layer and a high-barrier UV adhesive layer. Testing showed that the polarizer-made panel exhibited a bluing effect after only 750 hours at 80°C. Comparative Example 8's PSA adhesive layer contained more light-absorbing microcapsules than the maximum allowed. Since the light-absorbing agent absorbs not only blue light but also a small amount of other visible light, the transmittance of the polarizer was significantly reduced.

[0087] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A polarizer for suppressing blue emission from polarizers, comprising a PVA polarizer layer, an outer inner protective layer and an inner inner protective layer adhered to the upper and lower surfaces of the PVA polarizer layer, wherein a protective film is bonded to the outside of the outer inner protective layer, and a release film is bonded to the surface of the inner inner protective layer via a PSA adhesive layer, characterized in that: Both the outer inner protective layer and the inner inner protective layer are bonded to the PVA polarizer layer by a high-barrier UV adhesive layer; a surface barrier layer is also provided between the outer inner protective layer and the protective film; and microcapsules of light absorbers for absorbing blue light are added to the PSA adhesive layer.

2. The polarizer for suppressing blue emission of polarizers according to claim 1, characterized in that: The high-barrier UV adhesive layer is prepared by mixing 15-25 parts by weight of CELLOXIDE 2021P, 1-8 parts by weight of EPOLEAD GT401, 20-50 parts by weight of PLACACCEL M, 10-30 parts by weight of Kyoei EPOLIGHT 100MF, and 3-8 parts by weight of thioonium salt photoinitiator UVI-6976.

3. The polarizer for suppressing blue emission of polarizers according to claim 2, characterized in that: The thickness of the high-barrier UV adhesive layer is 2~4μm.

4. The polarizer for suppressing blue emission of polarizers according to claim 1, characterized in that: The surface barrier layer is formed by UV curing of 10-25 parts by weight of phenolic epoxy acrylate, 10-25 parts by weight of Daicel EPOLEAD GT401, 20-30 parts by weight of trimethylolpropane triacrylate, and 15-25 parts by weight of pentaerythritol tetraacrylate, initiated by 2-5 parts by weight of free radical initiator 184 and 0.5-2.0 parts by weight of cationic initiator IGM Omnicat 320.

5. The polarizer for suppressing blue emission of polarizers according to claim 4, characterized in that: The thickness of the surface barrier layer is 4~10μm.

6. The polarizer for suppressing blue emission of polarizers according to claim 1, characterized in that: The capsule wall of the light absorber microcapsule is made of polyvinyl alcohol or dextrin, and the capsule wall ruptures after 2 hours at a temperature of 60°C and a humidity of 90%.

7. The polarizer for suppressing blue emission of polarizers according to claim 6, characterized in that: The light absorber in the light absorber microcapsules is a blue-violet and ultraviolet light absorber that has significant absorption in the 260~450nm range.

8. The polarizer for suppressing blue emission of polarizers according to claim 7, characterized in that: The size of the light absorber microcapsules is 200nm~600nm, and the microcapsule wall thickness is 100~300nm; the amount of light absorber microcapsules added is 0.1%~1.3% of the dry weight of the PSA adhesive layer.

9. The method for preparing a polarizer that suppresses blue emission of polarizers as described in any one of claims 1 to 8, characterized in that... Includes the following steps: S1. Formulation of light-absorbing PSA adhesive S11. Using acrylate raw gum as the main agent, a PSA colloidal composition with a solid content of 17-20% is prepared. S12. Add the light absorber microcapsules to the above PSA colloidal composition at a ratio of 0.1~1.3% of the dry weight of the PSA adhesive, stir evenly and set aside for use. S2. Preparation of high-barrier UV adhesive 15-25 parts by weight of CELLOXIDE 2021P, 1-8 parts by weight of EPOLEAD GT401, 20-50 parts by weight of PLACACCEL M, 10-30 parts by weight of Kyoei EPOLIGHT 100MF, and 3-8 parts by weight of thioonium salt photoinitiator UVI-6976 are mixed evenly to obtain a high-barrier UV adhesive. S3. Preparation of the outer original film with a surface barrier layer 10-25 parts by weight of phenolic epoxy acrylate, 10-25 parts by weight of Daicel EPOLEAD GT401, 20-30 parts by weight of trimethylolpropane triacrylate, 15-25 parts by weight of pentaerythritol tetraacrylate, 2-5 parts by weight of free radical initiator 184, and 0.5-2.0 parts by weight of cationic initiator IGM Omnicat320 are stirred and mixed evenly, and then applied to one surface of the outer original film. After curing by ultraviolet irradiation, the outer original film with a surface barrier layer is obtained. S4. Preparation of polarizer S41. The PVA film is unwound at the first unwinding point, and then subjected to swelling, dyeing, bridging, stretching, washing, color fixing and drying to obtain a PVA polarizer. Inner protective layers are bonded to the upper and lower surfaces of the PVA polarizer with high-barrier UV adhesive. The outer layer is called the outer inner protective layer, and the non-bonded surface has a high-barrier surface coating. The other inner protective layer opposite to the outer inner protective layer is called the inner inner protective layer. S42. Unwind the release film at the second unwinding point, apply PSA adhesive containing light absorber, dry it in a drying oven, and then attach it to the inner protective layer. S43. Unwind the protective film at the third unwinding point, attach it to the inner protective layer of the outer layer, and then rewind to obtain the polarizer semi-finished product. S44. The semi-finished polarizing film is unwound at the cutting line, and then cut and edge-grinding is performed to obtain the finished sheet polarizing film.

10. The method for preparing a polarizer that suppresses blue emission of polarizers according to claim 9, characterized in that: In step S3, the inner protective layer of the outer layer is a PMMA film or a PET film; the ultraviolet light (UVA) used for curing reaches 500 mJ / cm. 2 Above, and UVB reaches 500 mJ / cm 2 above; In step S41, after bonding the outer and inner protective layers to the PVA polarizer surface using high-barrier UV adhesive, double-sided UV irradiation is used for curing, achieving a UVB intensity of 500 mJ / cm². 2 above.

Images