A glue for polarizing plate and a method for preparing the same

Abstract

The present application relates to a kind of polarizing sheet glue and its preparation method, it is made of the following weight parts of component: deionized water 80~92 parts, polyvinyl alcohol 3~5 parts, SPM-01 2~5 parts, anhydrous zinc chloride 0.1~0.5 parts, concentrated hydrochloric acid 0.1~0.3 parts, sodium hydroxide 0.025~0.042 parts and glyoxal solution 1~5 parts;In its preparation process, polyvinyl alcohol is dissolved in deionized water first, anhydrous zinc chloride, concentrated hydrochloric acid, sodium hydroxide solution, glyoxal solution and SPM-01 are added, and stirred evenly, it is obtained.The polarizing sheet glue provided by the present application has good polymerization effect, is coated uniformly when being bonded on polarizing sheet, is not easy to edge lifting, simultaneously has the advantages such as normal point defect, good water resistance and high yield, and the transmittance and polarization degree meet the requirements, is suitable for large-scale industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical polarizing element, and particularly relates to a glue for polarizing plate. BACKGROUND

[0002] At present, the glue for polarizing plate is mainly prepared by adding SPM-01 additive into raw glue (polyvinyl alcohol and deionized water). The polarizing plate prepared by using the glue will have obvious white edges (commonly known as PVA shrinkage) after being soaked in water at 60 DEG C for 1 hour, which indicates that the polarizing plate prepared by using the glue has poor water resistance, is easy to be damp, has short storage time, and will have color difference after long storage. SUMMARY

[0003] The present application aims to provide a glue for polarizing plate based on the prior art, which can solve the problems of poor water resistance, easy damp, short storage time and the like of the current glue for polarizing plate.

[0004] Another object of the present application is to provide a preparation method of the above glue for polarizing plate.

[0005] The technical scheme of the present application is as follows:

[0006] The glue for polarizing plate is prepared from the following components by weight: deionized water 80-92 parts, polyvinyl alcohol 3-5 parts, SPM-01 2-5 parts, anhydrous zinc chloride 0.1-0.5 parts, concentrated hydrochloric acid 0.1-0.3 parts, sodium hydroxide 0.025-0.042 parts and glyoxal solution 1-5 parts. In the preparation process, the polyvinyl alcohol is first dissolved in the deionized water by stirring, and then the mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, the sodium hydroxide solution, the glyoxal solution and the SPM-01 are added and stirred uniformly.

[0007] The components of the glue for polarizing plate provided by the present application include deionized water, polyvinyl alcohol, SPM-01, anhydrous zinc chloride, concentrated hydrochloric acid, sodium hydroxide and glyoxal solution. In the preparation process of the glue, the sodium hydroxide is mixed with other components in the form of sodium hydroxide solution, which has better preparation effect and can control the feeding speed of sodium hydroxide.

[0008] In a preferred embodiment, the preparation of the adhesive for the polarizing sheet comprises the following steps: (1) stirring and dissolving polyvinyl alcohol in deionized water at 25-35°C, and then continuing to stir and heat to 85-95°C; (2) cooling to 30-40°C, adding a prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, and stirring; (3) slowly adding a prepared sodium hydroxide solution, and stirring; (4) adding a glyoxal solution, and stirring; (5) adding SPM-01, and stirring until uniform, thereby obtaining the adhesive.

[0009] For the adhesive of the present application, the sodium hydroxide solution plays a crucial role. Without the sodium hydroxide solution, the PVA will shrink significantly after 2 hours, and the water resistance will be particularly poor. In the experiment, it was found that, in the preparation of the adhesive, other components and proportions were the same, only the sodium hydroxide solution was replaced by a similar alkaline solution, for example, a potassium hydroxide solution, and the adhesive prepared was used in the polarizing sheet. After 2 hours, the PVA had already shrunk significantly, and the water resistance was poor.

[0010] In the preparation of the adhesive, the addition of the sodium hydroxide solution can not only adjust the acid-base conditions of the adhesive, but also control the polymerization effect of the adhesive, thereby affecting the water resistance of the adhesive. Therefore, the amount of sodium hydroxide needs to be strictly controlled. If the amount of sodium hydroxide is too high or too low, the polymerization effect of the adhesive prepared will fail, the yield will be low, the water resistance will be poor, the adhesive will be easily damp, and the storage time will be short.

[0011] In addition, in the preparation of the adhesive, the feeding speed of the sodium hydroxide also needs to be controlled, and the specific amount of sodium hydroxide added in the adhesive per unit time is adjusted, so as to further control the polymerization time of the adhesive and avoid the problems of failure of the polymerization effect of the adhesive prepared, low yield, poor water resistance, etc. caused by too short polymerization time of the adhesive. In order to solve the problem of too fast feeding speed, the sodium hydroxide is first prepared into a low-concentration sodium hydroxide solution, and the feeding speed can be controlled by slow dripping to avoid the adverse effects caused by too fast feeding speed of the sodium hydroxide. For the present application, the mass fraction of the low-concentration sodium hydroxide solution is controlled at 0.5-1%, which can be but is not limited to 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, and preferably, the mass fraction of the sodium hydroxide solution is 0.8%. When the mass fraction of the sodium hydroxide solution is too high, even if the slow dripping method is used for feeding, the actual amount of sodium hydroxide added per unit time will be high, which will cause the same problems of failure of the polymerization effect of the adhesive prepared, low yield, poor water resistance, etc.

[0012] Although the component anhydrous zinc chloride is also included in the adhesive for polarizing plate disclosed in the prior art, it is generally used as a crosslinking agent to increase the adhesion of the adhesive, but in the present application, the anhydrous zinc chloride is dissolved in concentrated hydrochloric acid, and its function and principle are not the same, and for the present application, it is to increase the hydrophobicity of the adhesive, and therefore, in the process of preparing the adhesive, the feeding sequence of the components needs to be strictly controlled, otherwise, after the prepared adhesive is used in the polarizing plate, the PVA will be significantly shrunk after 2 hours, and the water resistance is poor. It is found in the experiment that the component anhydrous zinc chloride is essential, and in the process of preparing the adhesive, other components and proportions are the same, and only the anhydrous zinc chloride is replaced by similar chlorides, for example, magnesium chloride, and the prepared adhesive is used in the polarizing plate, and the PVA will be significantly shrunk after 2 hours, and the water resistance is poor.

[0013] In a preferred embodiment, the adhesive for polarizing plate of the present application is prepared from the following components by weight: deionized water 82-90 parts, polyvinyl alcohol 4-5 parts, SPM-01 4-5 parts, anhydrous zinc chloride 0.1-0.3 parts, concentrated hydrochloric acid 0.1-0.2 parts, sodium hydroxide 0.03-0.04 parts, and glyoxal solution 2-4 parts. In the preparation process, sodium hydroxide is first prepared into a sodium hydroxide solution, wherein the mass fraction of the sodium hydroxide solution is 0.5-1%.

[0014] In a more preferred embodiment, the adhesive for polarizing plate of the present application is prepared from the following components by weight: deionized water 85 parts, polyvinyl alcohol 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid 0.1 parts, sodium hydroxide 0.032 parts, and glyoxal solution 2.1 parts. In the preparation process, sodium hydroxide is first prepared into a sodium hydroxide solution, wherein the mass fraction of the sodium hydroxide solution is 0.8%.

[0015] In a more preferred embodiment, the adhesive for polarizing plate of the present application is prepared from the following components by weight: deionized water 82 parts, polyvinyl alcohol 5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.3 parts, concentrated hydrochloric acid 0.1 parts, sodium hydroxide 0.04 parts, and glyoxal solution 3.7 parts. In the preparation process, sodium hydroxide is first prepared into a sodium hydroxide solution, wherein the mass fraction of the sodium hydroxide solution is 0.8%.

[0016] In an embodiment, the polyvinyl alcohol in the present application is Z-200 or Z-300 of Nippon Shokubai Co., Ltd.

[0017] In an embodiment, the SPM-01 in the present application is prepared by Nippon Shokubai Co., Ltd.

[0018] In a preferred embodiment, the preparation of the adhesive for polarizing plate includes the following steps:

[0019] (1) stirring and dissolving polyvinyl alcohol in deionized water at 25-35℃, and then continuing to heat to 85-95℃ and stirring after stirring and dissolving;

[0020] (2) cooling to 30-40℃, adding the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, and stirring;

[0021] (3) slowly adding the prepared sodium hydroxide solution, and stirring;

[0022] (4) adding glyoxal solution, and stirring;

[0023] (5) adding SPM-01, and stirring uniformly to obtain the product.

[0024] In a preferred solution, in step (1), stirring and dissolving polyvinyl alcohol in deionized water at 30℃.

[0025] Further, after stirring and dissolving, continuing to heat to 90℃, and stirring for 0.5-3h;

[0026] Further, stirring for 1-2h.

[0027] In a preferred solution, in step (2), cooling to 32℃, adding the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, and stirring; further, the stirring time is 30-60min.

[0028] In a preferred solution, in step (3), the mass fraction of the sodium hydroxide solution is 0.5-1%, which can be but is not limited to 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, and further preferably, the mass fraction of the sodium hydroxide solution is 0.8%.

[0029] Further, the stirring time is 30-60min.

[0030] In a preferred solution, in step (4), the mass fraction of the glyoxal solution is 35-45%, which can be but is not limited to 35%, 36%, 38%, 39%, 40%, 41% or 45%, and further preferably, the mass fraction of the glyoxal solution is 40%.

[0031] Further, the stirring time is 30-60min.

[0032] In a preferred solution, in step (5), adding SPM-01, and the stirring time is 30-60min.

[0033] In a preferred solution, the preparation of the glue for polarizing plates provided by the present application comprises the following detailed steps:

[0034] (1) to the beaker, after uniform stirring at 30 DEG C, polyvinyl alcohol is added in small amounts for several times, until no clumps are formed, then after adding, stirring at 30 DEG C, the temperature is increased to 90 DEG C, and stirring is continued for 1-2 hours; then the temperature is decreased to 32 DEG C using a water bath;

[0035] (2) to the beaker, anhydrous zinc chloride is added, concentrated hydrochloric acid is added dropwise using a glass pipette, and stirring is continued until the anhydrous zinc chloride is completely dissolved, obtaining a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid; after the temperature in step (1) is decreased to 32 DEG C, the mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid prepared in step (2) is added dropwise slowly while stirring, and stirring is continued for 30-60 minutes at 30 DEG C;

[0036] (3) sodium hydroxide is dissolved in deionized water to prepare a 0.8% sodium hydroxide solution; after the stirring in step (2) is completed, the prepared sodium hydroxide solution is added dropwise slowly while stirring, and stirring is continued for 30-60 minutes after the dropwise addition is completed;

[0037] (4) after the stirring in step (3) is completed, the prepared glyoxal solution is added dropwise slowly while stirring, and stirring is continued for 30-60 minutes after the dropwise addition is completed;

[0038] (5) after the stirring in step (4) is completed, SPM-01 is added while stirring, and stirring is continued for 30-60 minutes after the dropwise addition is completed, obtaining the product.

[0039] The technical scheme of the present application has the following advantages:

[0040] The glue for polarizing plates provided by the present application has the advantages of good polymerization effect, uniform coating on the polarizing plate, no easy warping, normal point defects, good water resistance, high yield, and the like, and the transmittance and polarization degree meet the requirements, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a picture of the polarizing plate prepared from the glue in Example 1 and Comparative Example 1 immersed in a 60 DEG C water bath for 1 hour;

[0042] Figure 2 is a picture of the polarizing plate prepared from the glue in Example 1 and Comparative Example 1 immersed in a 60 DEG C water bath for 2 hours;

[0043] Figure 3 is a picture of the polarizing plate prepared from the glue in Example 1 and Comparative Example 1 immersed in a 60 DEG C water bath for 3 hours;

[0044] Figure 4 is the picture of the polarizing sheet made by the glue in Example 1 and Comparative Example 1 immersed in 60°C water bath for 4 hours;

[0045] Figure 5 is the picture of the polarizing sheet made by the glue in Example 1 and Comparative Example 1 immersed in 60°C water bath for 6 hours;

[0046] Figure 6 is the picture of the polarizing sheet made by the glue in Example 1 and Comparative Example 1 immersed in 60°C water bath for 24 hours;

[0047] Figure 7 is the picture of the polarizing sheet made by the glue in Example 2 immersed in 60°C water bath for 1-8 hours;

[0048] Figure 8 is the picture of the polarizing sheet made by the glue in Comparative Example 2 immersed in 60°C water bath for 2 hours;

[0049] Figure 9 is the picture of the polarizing sheet made by the glue in Comparative Example 3 immersed in 60°C water bath for 2 hours;

[0050] Figure 10 is the picture of the polarizing sheet made by the glue in Comparative Example 4 immersed in 60°C water bath for 2 hours;

[0051] Figure 11 is the picture of the polarizing sheet made by the glue in Comparative Example 4 immersed in 60°C water bath for 2 hours; DETAILED DESCRIPTION

[0052] The polarizing sheet glue of the present application is further illustrated by the following examples in conjunction with the accompanying drawings, but these examples do not constitute any limitation to the present application.

[0053] The components and proportions of the glue in the examples and comparative examples are shown in Table 1.

[0054] Table 1 Components and proportions of the polarizing sheet glue

[0055]

[0056] Note: In Comparative Example 11, "magnesium chloride" is used to replace "anhydrous zinc chloride", and in Comparative Example 12, "potassium hydroxide" is used to replace "sodium hydroxide"; concentrated hydrochloric acid (36.46%) means the mass fraction is 36.46%, and glyoxal solution (40%) means the mass fraction is 40%.

[0057] Example 1

[0058] A glue for polarizing sheet is made from the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid (36.46% by mass) 0.1 part, sodium hydroxide 0.032 part, and glyoxal solution (40% by mass) 2.1 parts.

[0059] The preparation process is as follows:

[0060] (1) Add deionized water to a beaker, and after uniform stirring at 30°C, add polyvinyl alcohol to the beaker in small amounts and multiple times, with no clumping, and after completion, stir at 30°C, and then warm up to 90°C, stirring for 1-2 hours; then cool down to 32°C using a water bath;

[0061] (2) Add anhydrous zinc chloride to the beaker, and add concentrated hydrochloric acid dropwise using a glass pipette, stirring slowly until the anhydrous zinc chloride is completely dissolved, obtaining a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid; after the temperature in step (1) is reduced to 32°C, continue stirring and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, continuing to stir at 30°C for 30-60 minutes;

[0062] (3) Dissolve sodium hydroxide in deionized water to prepare a 0.8% by mass sodium hydroxide solution; after the stirring in step (2) is completed, continue stirring and slowly add the prepared sodium hydroxide solution (4 parts), and after the addition is complete, continue stirring for 30-60 minutes;

[0063] (4) After the stirring in step (3) is completed, continue stirring and slowly add the glyoxal solution, and after the addition is complete, continue stirring for 30-60 minutes;

[0064] (5) After the stirring in step (4) is completed, continue stirring and add SPM-01, and after the addition is complete, continue stirring for 30-60 minutes, obtaining the product.

[0065] Example 2

[0066] A glue for polarizing sheet is made from the following components by weight: deionized water 82 parts, polyvinyl alcohol (Z-200) 5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.3 parts, concentrated hydrochloric acid (36.46% by mass) 0.1 part, sodium hydroxide 0.04 part, and glyoxal solution (40% by mass) 3.7 parts.

[0067] The preparation process is as follows, with reference to Example 1.

[0068] Comparative Example 1

[0069] A glue for polarizer, which is made from the following components by weight: deionized water 90 parts, polyvinyl alcohol (Z-200) 5 parts, SPM-01 5 parts.

[0070] The preparation process is as follows:

[0071] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol in small amounts, stir at 30°C, then heat to 90°C, stir for 1-2 hours, then cool to 32°C with a water bath;

[0072] (2) After the temperature in step (1) drops to 32°C, continue stirring and add SPM-01, continue stirring for 30-60 minutes after adding.

[0073] Comparative Example 2

[0074] A glue for polarizer, which is made from the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid (mass fraction 36.46%) 0.1 parts, and glyoxal solution (mass fraction 40%) 2.1 parts.

[0075] The preparation process is as follows:

[0076] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol in small amounts, stir at 30°C, then heat to 90°C, stir for 1-2 hours, then cool to 32°C with a water bath;

[0077] (2) Add anhydrous zinc chloride to the beaker, add concentrated hydrochloric acid dropwise with a glass pipette, slowly stir until the anhydrous zinc chloride is completely dissolved, to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid; continue stirring after the temperature in step (1) drops to 32°C, and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, continue stirring at 30°C for 30-60 minutes;

[0078] (3) After the stirring in step (2) is completed, continue stirring and slowly add the glyoxal solution, continue stirring for 30-60 minutes after adding.

[0079] (4) After the stirring in step (3) is completed, continue stirring and add SPM-01, continue stirring for 30-60 minutes after adding.

[0080] Comparative Example 3

[0081] A glue for polarizer, which is made of the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid (mass fraction 36.46%) 0.1 parts and sodium hydroxide 0.032 parts.

[0082] The preparation process is as follows:

[0083] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol to the beaker in small amounts, stir at 30°C, then heat to 90°C and stir for 1-2 hours, then cool to 32°C using a water bath;

[0084] (2) Add anhydrous zinc chloride to the beaker, use a glass pipette to add concentrated hydrochloric acid dropwise to the beaker, slowly stir until the anhydrous zinc chloride is completely dissolved to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid; after the temperature in step (1) is reduced to 32°C, continue to stir and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, continue to stir at a temperature of 30°C for 30-60 minutes;

[0085] (3) Dissolve sodium hydroxide in deionized water to prepare a 0.8% sodium hydroxide solution; after the stirring in step (2) is completed, continue to stir and slowly add the prepared sodium hydroxide solution (4 parts), after the addition is completed, continue to stir for 30-60 minutes;

[0086] (4) After the stirring in step (3) is completed, continue to stir and add SPM-01, after the addition is completed, continue to stir for 30-60 minutes to obtain the glue.

[0087] Comparative Example 4

[0088] The glue formula is the same as in Example 1, except that the order of adding the components sodium hydroxide and glyoxal solution is different, as follows:

[0089] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol to the beaker in small amounts, stir at 30°C, then heat to 90°C and stir for 1-2 hours, then cool to 32°C using a water bath;

[0090] (2) Add anhydrous zinc chloride to the beaker, use a glass pipette to add concentrated hydrochloric acid dropwise to the beaker, slowly stir until the anhydrous zinc chloride is completely dissolved to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid; after the temperature in step (1) is reduced to 32°C, continue to stir and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, continue to stir at a temperature of 30°C for 30-60 minutes;

[0091] (3) After the stirring in step (2) is completed, continue stirring and slowly add the glyoxal solution dropwise, and after the dropwise addition is completed, continue stirring for 30-60 min;

[0092] (4) Dissolve sodium hydroxide in deionized water to prepare a 0.8% sodium hydroxide solution by mass fraction; after the stirring in step (3) is completed, continue stirring and slowly add the prepared sodium hydroxide solution (4 parts) dropwise, and after the dropwise addition is completed, continue stirring for 30-60 min;

[0093] (5) After the stirring in step (4) is completed, continue stirring and add SPM-01, and after the dropwise addition is completed, continue stirring for 30-60 min.

[0094] Comparative Example 5

[0095] The glue formula is the same as in Example 1, except that the addition order of some components is different, as follows:

[0096] (1) Add deionized water to a beaker, and after uniform stirring at 30°C, add polyvinyl alcohol to the beaker in small amounts and multiple times, until no clumps are formed. After addition is completed, stir at 30°C, and then increase the temperature to 90°C and stir for 1-2 h. Then use a water bath to reduce the temperature to 32°C;

[0097] (2) Add anhydrous zinc chloride to the beaker, and use a glass pipette to add concentrated hydrochloric acid dropwise to the beaker. Slowly stir until the anhydrous zinc chloride is completely dissolved, to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid. After the temperature in step (1) is reduced to 32°C, continue stirring and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid dropwise, and continue stirring at a temperature of 30°C for 30-60 min;

[0098] (3) Dissolve sodium hydroxide in deionized water to prepare a 0.8% sodium hydroxide solution by mass fraction; after the stirring in step (2) is completed, continue stirring and slowly add the prepared sodium hydroxide solution (4 parts) dropwise, and after the dropwise addition is completed, continue stirring for 30-60 min;

[0099] (4) After the stirring in step (3) is completed, continue stirring and add SPM-01, and after the dropwise addition is completed, continue stirring for 30-60 min.

[0100] (5) After the stirring in step (4) is completed, continue stirring and slowly add the glyoxal solution dropwise, and after the dropwise addition is completed, continue stirring for 30-60 min;.

[0101] Comparative Example 6

[0102] A glue for polarizer, which is made of the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, sodium hydroxide 0.032 parts and glyoxal solution (mass fraction 40%) 2.1 parts.

[0103] The preparation process is as follows:

[0104] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol to the beaker in small amounts, stir at 30°C, then heat to 90°C and stir for 1-2 hours; then cool to 32°C with a water bath;

[0105] (2) After the temperature in step (1) drops to 32°C, continue stirring and slowly add anhydrous zinc chloride, stir to dissolve, then continue stirring at 30°C for 30-60 minutes;

[0106] (3) Dissolve sodium hydroxide in deionized water to prepare a 0.8% sodium hydroxide solution; after step (2) is completed, continue stirring and slowly add the prepared sodium hydroxide solution (4 parts), then continue stirring for 30-60 minutes after the addition is complete;

[0107] (4) After step (3) is completed, continue stirring and slowly add the glyoxal solution, then continue stirring for 30-60 minutes after the addition is complete;

[0108] (5) After step (4) is completed, continue stirring and add SPM-01, then continue stirring for 30-60 minutes after the addition is complete.

[0109] Comparative Example 7

[0110] A glue for polarizer, which is made of the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid (mass fraction 36.46%) 0.1 parts, sodium hydroxide 0.048 parts and glyoxal solution (mass fraction 40%) 2.1 parts.

[0111] The preparation process is as follows:

[0112] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol to the beaker in small amounts, stir at 30°C, then heat to 90°C and stir for 1-2 hours; then cool to 32°C with a water bath;

[0113] (2) Add anhydrous zinc chloride into the beaker, and drop concentrated hydrochloric acid into the beaker with a glass pipette, slowly stir until the anhydrous zinc chloride is completely dissolved to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid; after the temperature in step (1) is reduced to 32°C, continue to stir and slowly drop the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, continuously stir for 30-60 min at a temperature of 30°C;

[0114] (3) Stir and dissolve sodium hydroxide in deionized water to prepare a 0.8% mass fraction sodium hydroxide solution; after the stirring in step (2) is completed, continue to stir and slowly drop the prepared sodium hydroxide solution (6 parts), after the dropping is completed, continuously stir for 30-60 min;

[0115] (4) After the stirring in step (3) is completed, continue to stir and slowly drop the glyoxal solution, after the dropping is completed, continuously stir for 30-60 min;

[0116] (5) After the stirring in step (4) is completed, continue to stir and add SPM-01, after the dropping is completed, continuously stir for 30-60 min, and the glue for polarizing plate is obtained.

[0117] Comparative Example 8

[0118] A glue for polarizing plate is prepared from the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, and sodium hydroxide 0.032 parts.

[0119] The preparation process is as follows:

[0120] (1) Add deionized water into the beaker, after uniform stirring at 30°C, add polyvinyl alcohol into the beaker in small amounts for several times, and the addition is completed when no clumps are formed, then after the temperature is increased to 90°C, stir for 1-2 h, and then reduce the temperature to 32°C with a water bath;

[0121] (2) After the temperature in step (1) is reduced to 32°C, continue to stir and slowly drop anhydrous zinc chloride, after the stirring and dissolution, continuously stir for 30-60 min at a temperature of 30°C;

[0122] (3) Stir and dissolve sodium hydroxide in deionized water to prepare a 0.8% mass fraction sodium hydroxide solution; after the stirring in step (2) is completed, continue to stir and slowly drop the prepared sodium hydroxide solution (4 parts), after the dropping is completed, continuously stir for 30-60 min;

[0123] (4) After the stirring in step (3) is completed, continue to stir and add SPM-01, after the dropping is completed, continuously stir for 30-60 min, and the glue for polarizing plate is obtained.

[0124] Comparative Example 9

[0125] A glue for polarizer, which is made of the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, concentrated hydrochloric acid (mass fraction 36.46%) 0.1 parts and glyoxal solution (mass fraction 40%) 2.1 parts.

[0126] The preparation process is as follows:

[0127] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol in small amounts and multiple times, not to form lumps, after adding, stir at 30°C, then warm up to 90°C, stir for 1-2h, then cool down to 32°C with water bath;

[0128] (2) After the temperature in step (1) drops to 32°C, continue to stir and slowly add concentrated hydrochloric acid, after adding, continue to stir at 30°C for 30-60min;

[0129] (3) After the stirring in step (2) is completed, continue to stir and slowly add glyoxal solution, after adding, continue to stir for 30-60min;

[0130] (4) After the stirring in step (3) is completed, continue to stir and add SPM-01, after adding, continue to stir for 30-60min, and it is obtained.

[0131] Comparative Example 10

[0132] A glue for polarizer, which is made of the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, zinc chloride anhydrous 0.2 parts and glyoxal solution (mass fraction 40%) 2.1 parts.

[0133] The preparation process is as follows:

[0134] (1) Add deionized water to a beaker, stir evenly at 30°C, then add polyvinyl alcohol in small amounts and multiple times, not to form lumps, after adding, stir at 30°C, then warm up to 90°C, stir for 1-2h, then cool down to 32°C with water bath;

[0135] (2) After the temperature in step (1) drops to 32°C, continue to stir and slowly add zinc chloride anhydrous, after stirring and dissolving, continue to stir at 30°C for 30-60min;

[0136] (3) After the stirring in step (2) is completed, continue to stir and slowly add glyoxal solution, after adding, continue to stir for 30-60min;

[0137] (4) After the end of the stirring in step (3), continue to stir and add SPM-01, after the dropwise addition is completed, continue to stir for 30-60 min, and the glue for polarizing plate is obtained.

[0138] Comparative Example 11

[0139] A glue for polarizing plate is prepared from the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, magnesium chloride 0.2 parts, concentrated hydrochloric acid (mass fraction 36.46%) 0.1 part, sodium hydroxide 0.032 part, and glyoxal solution (mass fraction 40%) 2.1 parts.

[0140] The preparation process is as follows:

[0141] (1) Add deionized water to a beaker, and after uniform stirring at 30°C, add polyvinyl alcohol to the beaker in small amounts and multiple times, with no clumping as the criterion. After addition is complete, stir at 30°C, then increase the temperature to 90°C and stir for 1-2 h. Then cool to 32°C using a water bath;

[0142] (2) Add magnesium chloride to the beaker, and using a glass pipette, add concentrated hydrochloric acid dropwise to the beaker. Slowly stir until the magnesium chloride is completely dissolved, obtaining a mixed solution of magnesium chloride and concentrated hydrochloric acid. After the temperature in step (1) is reduced to 32°C, continue to stir and slowly add the prepared mixed solution of magnesium chloride and concentrated hydrochloric acid, and continue to stir at a temperature of 30°C for 30-60 min;

[0143] (3) Dissolve sodium hydroxide in deionized water to prepare a 0.8% sodium hydroxide solution by mass. After the end of the stirring in step (2), continue to stir and slowly add the prepared sodium hydroxide solution (4 parts), and after the dropwise addition is completed, continue to stir for 30-60 min;

[0144] (4) After the end of the stirring in step (3), continue to stir and slowly add the glyoxal solution, and after the dropwise addition is completed, continue to stir for 30-60 min;

[0145] (5) After the end of the stirring in step (4), continue to stir and add SPM-01, and after the dropwise addition is completed, continue to stir for 30-60 min, and the glue for polarizing plate is obtained.

[0146] Comparative Example 12

[0147] A glue for polarizing plate is prepared from the following components by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid (mass fraction 36.46%) 0.1 part, potassium hydroxide 0.032 part, and glyoxal solution (mass fraction 40%) 2.1 parts.

[0148] The preparation process is as follows:

[0149] (1) Add deionized water to a beaker, and after uniform stirring at 30°C, add polyvinyl alcohol to the beaker in small amounts for several times, until no clumps are formed. After completion of the addition, stir at 30°C, and then increase the temperature to 90°C and stir for 1-2 h. Then cool to 32°C using a water bath;

[0150] (2) Add anhydrous zinc chloride to the beaker, and drop concentrated hydrochloric acid into the beaker using a glass pipette. Slowly stir until the anhydrous zinc chloride is completely dissolved, to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid. After the temperature in step (1) is reduced to 32°C, continue stirring and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, and continue stirring at 30°C for 30-60 min;

[0151] (3) Dissolve potassium hydroxide in deionized water to prepare a 0.8% by mass potassium hydroxide solution. After the stirring in step (2) is completed, continue stirring and slowly add the prepared potassium hydroxide solution (4 parts). After the addition is completed, continue stirring for 30-60 min;

[0152] (4) After the stirring in step (3) is completed, continue stirring and slowly add the glyoxal solution. After the addition is completed, continue stirring for 30-60 min;

[0153] (5) After the stirring in step (4) is completed, continue stirring and add SPM-01. After the addition is completed, continue stirring for 30-60 min, to obtain the product.

[0154] Comparative Example 13

[0155] A glue for polarizing plates is prepared from the following components in parts by weight: deionized water 85 parts, polyvinyl alcohol (Z-200) 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid (36.46% by mass) 0.1 parts, sodium hydroxide 0.024 parts, and glyoxal solution (40% by mass) 2.1 parts.

[0156] The preparation process is as follows:

[0157] (1) Add deionized water to a beaker, and after uniform stirring at 30°C, add polyvinyl alcohol to the beaker in small amounts for several times, until no clumps are formed. After completion of the addition, stir at 30°C, and then increase the temperature to 90°C and stir for 1-2 h. Then cool to 32°C using a water bath;

[0158] (2) Add anhydrous zinc chloride to a beaker, and use a glass pipette to add concentrated hydrochloric acid dropwise to the beaker. Stir slowly until the anhydrous zinc chloride is completely dissolved to obtain a mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid. After the temperature in step (1) drops to 32°C, continue stirring and slowly add the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid. Continue stirring at 30°C for 30 to 60 minutes.

[0159] (3) Add sodium hydroxide to deionized water and stir to dissolve it, so as to prepare a sodium hydroxide solution with a mass fraction of 0.8%; after the stirring in step (2) is completed, continue stirring and slowly add the prepared sodium hydroxide solution (3 parts). After the addition is completed, continue stirring for 30 to 60 minutes.

[0160] (4) After the stirring in step (3) is completed, continue stirring and slowly add glyoxal solution. After the addition is completed, continue stirring for 30 to 60 minutes.

[0161] (5) After the stirring in step (4) is completed, continue stirring and add SPM-01. After the addition is complete, continue stirring for 30 to 60 minutes to obtain the product.

[0162] The following is an analysis of the test results after the glue was used on the polarizer:

[0163] In Example 1 and Comparative Example 1, the adhesive was applied to the polarizer and then immersed in a 60°C water bath for 1–24 hours to test its water resistance. The relevant experimental data are shown in Table 2.

[0164] Table 2. Water resistance data of the adhesive used after polarizers in Example 1 and Comparative Example 1.

[0165] Test time Example 1 Comparative Example 1 1 hour White edge 0.3 mm White edge 0.8 mm 2 hours White edge 0.5 mm White edge 1.0 mm 3 hours White edge 0.5 mm White edge 1.3 mm 4 hours White edge 0.5 mm Shrinkage at four corners 6 hours White edge 0.8 mm Severe shrinkage at four corners 24 hours Shrinkage Particularly severe shrinkage at four corners

[0166] As shown in Table 2, in Example 1, after the adhesive was applied to the polarizer, the white edge was about 0.5 mm within 4 hours, and the white edge phenomenon was not obvious. A more obvious white edge appeared after 6 hours, with a white edge of 0.8 mm, indicating good water resistance. In contrast, in Comparative Example 1, after the adhesive was applied to the polarizer, the white edge was about 0.8 mm within 1 hour, and a more obvious white edge appeared. After 4 hours, obvious PVA shrinkage occurred, and the water resistance was far inferior to that of Example 1 in this application.

[0167] In Example 2 and Comparative Examples 2-4, the adhesives were used on polarizers and then immersed in a 60°C water bath to test their water resistance. The relevant experimental data are shown in Table 3.

[0168] Table 3. Water resistance data of the adhesives used in Examples 2 and Comparative Examples 2-4 after polarizing films.

[0169]

[0170] From Table 1 and Table 2, compared with Example 1, in Example 2, the glue is used after the polarizer, within 1 hour, the white edge is about 0.5mm, after 2 hours, the white edge is obviously, the white edge is 0.8mm, the PVA shrinkage phenomenon appears, the water resistance is slightly poor; in Comparative Example 2, Comparative Example 3 and Comparative Example 4, the glue is used after the polarizer, after 2 hours, the white edge is obvious, the PVA shrinkage phenomenon appears obviously, the water resistance is poor.

[0171] In order to more clearly understand the test results of the glue used after the polarizer in the examples and comparative examples, the water resistance, the transmittance and the polarization degree, and the product appearance results are extracted and shown in Table 4.

[0172] Table 4 Comparison of test results of the glue used after the polarizer in the examples and comparative examples

[0173]

[0174]

[0175] Note: The transmittance, (L, a, b) value, polarization degree are measured by the ultraviolet spectrophotometer which is unifiedly certified by the industry, and the product appearance is detected by the naked eye of the production online quality personnel.

[0176] From Table 4, it can be seen that the glue provided by the application has the advantages of normal point defects, good water resistance and high yield when used after the polarizer; if one or more components in the application are omitted or replaced, and the feeding order of the components is changed, the glue prepared in this way has the PVA shrinkage phenomenon obviously after 2 hours, and the water resistance is poor.

[0177] From Comparative Example 2, Comparative Example 7, Comparative Example 12 and Comparative Example 13, it can be seen that the sodium hydroxide solution plays a crucial role in the preparation of the glue, if the sodium hydroxide solution is not added, the sodium hydroxide is excessive or insufficient, or the sodium hydroxide solution is replaced by potassium hydroxide solution, including the glue prepared by insufficient sodium hydroxide, the PVA shrinkage phenomenon appears obviously after 2 hours, the water resistance is particularly poor, and small white spots appear intermittently in the appearance of the finished product, which affects the product appearance and yield.

[0178] From Comparative Example 4 and Comparative Example 5, it can be seen that the feeding order of the components is changed in the preparation of the glue, and the glue prepared in this way has the PVA shrinkage phenomenon obviously after 2 hours, and the water resistance is poor.

[0179] From Comparative Example 11, it can be seen that the anhydrous zinc chloride plays a crucial role in the preparation of the glue, under the same conditions of other components, ratio and preparation method, if the anhydrous zinc chloride is replaced by magnesium chloride, the glue prepared in this way has the PVA shrinkage phenomenon obviously after 2 hours, the water resistance is particularly poor, and small white spots appear intermittently in the appearance of the finished product, which affects the product appearance and yield.

[0180] The polarizing sheet water resistance detection method provided by the present application comprises the following steps:

[0181] (1) The polarizing sheet cutting mode schematic diagram is shown as Figure 11 .

[0182] In the Figure 11 , the rectangle ABCD is regarded as a whole polarizing sheet produced by the present application, the AB side and the CD side are the operation side and the driving side of the production line respectively. The rectangle EFGH is a small sample cut from the polarizing sheet ABCD, which is 6 cm long and 4 cm wide, and the included angle between the HF side and the DB side is ∠FHI=45°;

[0183] (2) Put the small sample in step (1) into a constant temperature water bath at 60℃ and soak for a certain time, then take it out, measure the white edge with a scale, if the sample is taken out after 4 hours and the white edge is less than 1mm, it is regarded as good water resistance; if the sample is taken out after 1 hour and the white edge is more than 1mm, it is regarded as very poor water resistance; if the sample taken out appears PVA shrinkage phenomenon, it is also regarded as very poor water resistance.

[0184] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that it is still possible to modify the technical solutions recorded in the foregoing examples, or to make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An adhesive for polarizing films, characterized in that, It is made of the following components by weight: deionized water 80~92 parts, polyvinyl alcohol 3~5 parts, SPM-01 2~5 parts, anhydrous zinc chloride 0.1~0.5 parts, concentrated hydrochloric acid 0.1~0.3 parts, sodium hydroxide 0.025~0.042 parts and glyoxal solution 1~5 parts; The preparation of the adhesive for the polarizing sheet comprises the following steps: (1) stirring and dissolving polyvinyl alcohol in deionized water at 25~35℃, and then continuing to heat to 85~95℃ and stirring; (2) cooling to 30~40℃, adding the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, and stirring; (3) slowly adding the prepared sodium hydroxide solution, and stirring; (4) adding glyoxal solution, and stirring; (5) adding SPM-01, and stirring uniformly to obtain the adhesive. The polyvinyl alcohol is Z-200 or Z-300 of Japan Synthetic Chemical Industry Co., Ltd. or a combination thereof; the SPM-01 is prepared by Japan Synthetic Chemical Industry Co., Ltd.; the mass fraction of the sodium hydroxide solution is 0.5~1%; the mass fraction of the concentrated hydrochloric acid is 36~38%; and the mass fraction of the glyoxal solution is 35~45%.

2. The adhesive for polarizing plates according to claim 1, characterized by The adhesive for the polarizing sheet is made of the following components by weight: deionized water 82~90 parts, polyvinyl alcohol 4~5 parts, SPM-01 4~5 parts, anhydrous zinc chloride 0.1~0.3 parts, concentrated hydrochloric acid 0.1~0.2 parts, sodium hydroxide 0.03~0.04 parts and glyoxal solution 2~4 parts.

3. The adhesive for polarizing plates according to claim 1, characterized by The adhesive for the polarizing sheet is made of the following components by weight: deionized water 85 parts, polyvinyl alcohol 4.5 parts, SPM-01 4 parts, anhydrous zinc chloride 0.2 parts, concentrated hydrochloric acid 0.1 parts, sodium hydroxide 0.032 parts and glyoxal solution 2.1 parts.

4. The adhesive for polarizing plates according to claim 1, characterized by The mass fraction of the sodium hydroxide solution is 0.8%; the mass fraction of the concentrated hydrochloric acid is 36.5%; and the mass fraction of the glyoxal solution is 40%.

5. The method for producing the adhesive for polarizing plates according to claim 1, characterized by, It comprises the following steps: (1) stirring and dissolving polyvinyl alcohol in deionized water at 25~35℃, and then continuing to heat to 85~95℃ and stirring; (2) cooling to 30~40℃, adding the prepared mixed solution of anhydrous zinc chloride and concentrated hydrochloric acid, and stirring; (3) slowly adding the prepared sodium hydroxide solution, and stirring; (4) adding glyoxal solution, and stirring; (5) adding SPM-01, and stirring uniformly to obtain the adhesive. In step (2), the mass fraction of the concentrated hydrochloric acid is 36~38%; in step (3), the mass fraction of the sodium hydroxide solution is 0.5~1%; and in step (4), the mass fraction of the glyoxal solution is 35~45%.

6. The method for producing a polarizing plate adhesive according to claim 5, wherein In step (1), the polyvinyl alcohol is stirred and dissolved in deionized water at 30℃; after stirring and dissolving, the temperature is continued to be raised to 90℃, and stirring is performed for 0.5~3h.

7. The method for producing a polarizing plate adhesive according to claim 6, wherein In step (1), the stirring is performed for 1~2h.

8. The method for producing a polarizing plate adhesive according to claim 5, wherein In step (2), the stirring time is 30-60 min, the mass fraction of the concentrated hydrochloric acid is 36.5%, in step (3), the mass fraction of the sodium hydroxide solution is 0.8%, the stirring time is 30-60 min, in step (4), the mass fraction of the glyoxal solution is 40%, the stirring time is 30-60 min, and in step (5), the SPM-01 is added, and the stirring time is 30-60 min.

Images