CN111045139B

CN111045139B - Preparation method of raincoat brim polaroid

Info

Publication number: CN111045139B
Application number: CN201911363588.6A
Authority: CN
Inventors: 蔡再生; 靳凯丽; 候科如; 陈雷龙
Original assignee: Shanghai Leijing Rain Gear Co ltd; Donghua University
Current assignee: Shanghai Leijing Rain Gear Co ltd; Donghua University
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2022-02-01
Anticipated expiration: 2039-12-26
Also published as: CN111045139A

Abstract

The invention relates to a preparation method of a polaroid of a raincoat brim. The method comprises the following steps: coating the cleaned PVA film with dye solution, drying, fixing color with steam, cooling and cleaning. The method can effectively improve the dyeing uniformity, the extension uniformity and the stability of the PVA film polaroid.

Description

Preparation method of raincoat brim polaroid

Technical Field

The invention belongs to the field of preparation of polaroids, and particularly relates to a preparation method of a polaroid of a raincoat brim.

Background

In subtropical and temperate regions, rainwater always accompanies people all the year round, but umbrella holding is inconvenient for carrying things and is inconvenient to use under extremely harsh weather conditions, so that many people can choose a raincoat, especially an electric vehicle or a motorcycle for going out on a rainy day. Although a cord which can be tightly drawn is arranged at the opening of the head of the traditional raincoat, the head of the raincoat and the head of a rider cannot be integrated in a rainy or snowy day, particularly in a heavy rainy or snowy day, so that the sight of eyes of the rider is blocked by the raincoat when the rider bends left and right, the rider can not ride normally, and the rider is easy to injure and die when falling down or having traffic accidents due to the fact that no protective equipment is arranged. In addition, the rain-shading brim of a hat of present raincoat all is transparent plastic material mostly, rides passerby and is disturbed the sight by car light and ground ponding easily when going at rainy night to lead to the emergence of accident.

The polarizing plate is generally a composite material in which a polarizing film, an inner protective film, a pressure-sensitive adhesive layer, and an outer protective film are laminated, and has a function of shielding and transmitting incident light, and allows either longitudinal light or transverse light to be transmitted, or both. The polarizing plate with the polarizing axis in the up-down direction, namely the direction vertical to the ground can eliminate the reflection of part of water surface, road surface and ice and snow ground. The polaroid is used as a rain shielding plate of the raincoat, and can be stretched and moved by design, so that the reflected light entering the eyes of a rider can be weakened or disappeared, the front road can be clearly seen, and the oncoming rainwater can be shielded.

The prior polaroid is a polarizing film formed by spraying a polarizing coating on a PVA lining film, and the adopted methods mainly comprise an extension method and a coating method, wherein the extension method is the current mainstream process. The polarizer production technology is divided by the extension process of a PVA film, and has two main types, namely a dry method and a wet method. The dry method means that the PVA film is extended in a steam environment with certain temperature and humidity conditions, the method can improve the production efficiency of the process, and the PVA film with larger width is used for production without frequent film breaking. For example, the PVA film is swollen in water of 60 ℃ for 5min, then dyed in a dyeing solution prepared from a 40g/L potassium iodide solution and a 4g/L iodine solution for 3min, finally uniaxially stretched 5.0 times in a crosslinking solution prepared from a 40g/L boric acid solution and a 40g/L potassium iodide solution, and dried to obtain the PVA polarizer (patent publication No. CN107417941A entitled production method of PVA film and preparation method of PVA polarizer). However, this process has a limitation in that the uniformity of the PVA film during the stretching process is limited, and thus the complex tension, the uniformity of color tone and the durability of the polarizer raw film formed are not easily stabilized, and thus are less practical. The wet method refers to a process method for dyeing and stretching the PVA film in liquid with a certain proportion. The early limitations of this process were that the PVA film was difficult to control stably in the liquid extension, and therefore the PVA film was easily broken during processing, and the width of the PVA film was limited. The invention synchronously realizes the stretching and dyeing of the PVA film in a steaming box with certain humidity, the dye enters the PVA film along with the movement of a molecular chain in the stretching process to realize uniform dyeing, and the PVA film is stretched in the presence of water molecules, thereby avoiding the defects of stretching non-uniformity under dry conditions and difficult control of stability during liquid state stretching.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for preparing a polaroid of a raincoat brim, so as to overcome the defect that the uniformity and stability of a PVA film in the extending process are difficult to control in the prior art.

The invention provides a polaroid for raincoat brim, which is obtained by coating a PVA film subjected to boric acid crosslinking treatment with a mixed solution of a paste and a dye, drying and performing steam fixation.

The paste is one of sodium alginate, sodium carboxymethyl starch, etherified vegetable gum, synthetic paste and emulsifying paste.

The dye is one of bisazo polarizing dye, trisazo polarizing dye, anthraquinone dichroic dye, triphenyltriazine and derivative dichroic dye thereof, and monomethine and polymethine dichroic dye.

The PVA film has a thickness of 40-80 μm and a polymerization degree of 3500-5000.

The invention also provides a preparation method of the polaroid of the raincoat brim, which comprises the following steps:

the PVA film that will wash is soaked in the boric acid cross-linking liquid and is crosslinked, and the PVA film after the cross-linking modification is with dye liquor coating, dries, and the steam fixation cools off, washs, obtains raincoat brim of a hat polaroid, and wherein the concentration of boric acid is 20 ~ 50g/L in the boric acid processing liquid, and the dye liquor includes: 2-6 g/L of paste, 0.5-4 g/L of dye and water.

The PVA film is cleaned by the following steps: the PVA film was washed with ethanol and dried.

The method for crosslinking the washed PVA film by immersing the washed PVA film in boric acid crosslinking solution comprises the following steps: and (3) immersing the cleaned PVA film into a boric acid solution at the temperature of 50-70 ℃ for reaction for 3-8 min.

The coating is a floating knife coating 1-2 layers.

The drying temperature is 40-60 ℃, and the drying time is 10-40 min. If the drying temperature is too low, the water in the coating is volatilized slowly and is high, so that the PVA film is easy to soften, and the subsequent baking is influenced.

The steam fixation process parameters are as follows: the temperature is 70-90 ℃, the humidity is 70-100%, and the stretching multiple is 2-5 times. If the baking temperature is too low, the glass transition temperature of the PVA is not reached, the macromolecular chain of the PVA does not move, the dye cannot enter the PVA film, and the dyeing and the stretching of the PVA film cannot be finished. The PVA film deforms when the temperature is too high. In addition, the low humidity affects the uniformity of the PVA film in the stretching process, and the proper humidity is selected according to the used dichroic dye.

The invention also provides an application of the polaroid in a raincoat brim.

The paste dosage is 2-6 g/L, and the dye dosage is 0.5-4 g/L. If the amount of paste used is low, the coating is too thin to adhere well to the PVA film. If the paste is used in too high an amount, the coating is too thick and it is difficult to coat the coating. If the dye dosage is too low, the polarizing effect is not achieved, and too much color is darker, which affects the permeability.

The invention combines the dry process and the wet process by introducing a textile printing method, namely coating dye-containing paste on a PVA sheet, and then applying tension at proper temperature and humidity, so that dye molecules enter the PVA sheet and are directionally arranged to realize the polarization performance. The principle of the invention is as follows:

the common transparent plastic plate can only reduce the intensity of glare and ultraviolet light, but cannot completely block, namely, the common transparent plastic plate can only reduce the transmittance of light to darken a scene, but the scene under the glare is still unclear, and the influence of the glare cannot be completely eliminated. Compared with the common transparent plastic plate, the polarizing plastic plate has the polarizing property, can completely block dazzling glare caused by various factors such as scattering, reflection and the like, and is mainly used for eliminating glare interference in a specific direction and reducing light in other directions less; meanwhile, ultraviolet rays harmful to eyes can be completely blocked, so that the eyes are not easy to tire under the condition of existence of strong reflected light, the function of real protection is achieved, and objects seen can be clearer and more stereoscopic. Particularly, the polaroid with the polarization axis in the vertical direction, namely the direction vertical to the ground can eliminate the reflection of part of water surface, road surface and ice and snow ground, and is suitable for the riders of motorcycles and electric vehicles to use in rainy days. The core layer for polarizing of the polarizer commonly used at present is a PVA film, which determines key indexes of the polarizer such as polarizing performance, transmittance and color tone. The PVA molecules are originally distributed at any angle, and gradually deflect in the acting force direction after being stressed and stretched under the condition of certain temperature and humidity, and tend to be distributed linearly, so that the iodine molecules or dye molecules adsorbed on the PVA layer also deflect directionally along with the iodine molecules or dye molecules to form long chains of the iodine molecules or dye molecules. Because iodine molecules or dye molecules have good polarization, the iodine molecules or dye molecules can absorb polarized light parallel to the arrangement direction of the iodine molecules or dye molecules and only allow polarized light in the vertical direction to pass through.

The PVA film of the invention can improve the heat resistance after being modified by boric acid. When a coating material containing a dichroic dye and a paste is applied to a cross-linked modified PVA film, the paste has a dispersing function, and thus prevents the dyes from being bonded to each other and the dyes and the paste from being bonded to each other, thereby being uniformly distributed on the PVA film during the coating process. Under the condition of pre-baking, the water in the coating is slowly evaporated to prevent the coating from rapidly migrating to the surface of the PVA film to cause uneven dyeing. And (3) fixing color under the condition of the glass transition temperature higher than the PVA, wherein the dye in the coating jumps into the PVA film along with the movement of the PVA molecular chain, and is fixed in the PVA film when the temperature is reduced to the glass transition temperature of the PVA, so that the dyeing is finished. In addition, the printing paste can absorb steam in the steam fixation process, so that the PVA film is stretched in a relatively humid environment, and the uniformity and the durability of the stretched PVA film can be improved. The dyed PVA film is then washed to remove the thickener and surface bloom. As the fixation temperature is higher than the vitrification conversion temperature of PVA, PVA macromolecules and dye molecules are directionally stretched to form a polarizing shaft in the fixation process, thereby realizing one-step completion of dyeing and stretching.

The detection method comprises the following steps:

and (3) detecting the polarization degree: a good polaroid with polarization degree, light transmittance and surface defect-free is selected as an analyzer, then the detected polaroid is placed on a rotary objective table (round scales are marked on the objective table) on the analyzer, and different market brightness can be observed under different rotation angles by rotating the objective table. When the polarization axes of the two polarizing plates are parallel to each other, the transmittance of light is maximized. When the two polarization axes are perpendicular to each other, the transmittance of light is the minimum, i.e., the light intensity is 0. The degree of polarization of the polarizer can be calculated according to the following formula;

p is the polarization degree of the polaroid, A is the total field area observed when the analyzer is orthogonal to the polaroid to be detected, and a is the area of light leakage part in the field of view when the analyzer is orthogonal to the polaroid to be detected.

And (3) detecting the light transmittance:

the polarizer was placed in front of the receiver in the spectrophotometer and after scanning through the plate with various frequencies of light, the transmittance curve (a) from the first scan was recorded by the automatic recorder. And then rotating the polarizer to be detected by 90 degrees at the original placement position, performing second ray projection scanning, and recording a second scanning transmittance curve. The curves obtained in the two times are integrated in the same wave band to draw a new transmittance curve (A-B). This curve is the true transmittance curve of the polarizer to be inspected. In this curve, the transmittance of the sheet in each region can be intuitively obtained.

Advantageous effects

(1) The invention introduces the fabric coating process, the process is simple, and the cost is low;

(2) the invention can effectively improve the dyeing uniformity, the extension uniformity and the stability of the PVA film polaroid.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

The disazo-based dichroic dye blue A-R is provided by Lichangshan dyes science and technology company.

Example 1

And ultrasonically cleaning the PVA film with the thickness of 60 mu m in absolute ethyl alcohol, and airing. And then, soaking the cleaned PVA film into 30g/L boric acid solution, carrying out crosslinking reaction at 70 ℃ for 5min, cleaning with deionized water for three times, and drying at 40 ℃ for 30 min. Dissolving 2g/L sodium alginate in 500L water, stirring, adding 0.5g/L bisazo type dichroic dye blue A-R, and stirring. The method comprises the steps of uniformly coating a coating color paste on a cleaned PVA film by adopting a suspension coating method, drying the coated PVA film for 30min at 40 ℃, slowly applying tension to the PVA in an environment with the temperature of 80 ℃ and the humidity of 100%, stretching the PVA by 4 times, and simultaneously finishing dyeing of a dye so as to finish dyeing of the dye and directional stretching of the PVC film, thereby obtaining the polaroid of the raincoat brim.

The polarizing degree of the polarizing film obtained was measured to be 85% and the light transmittance was measured to be 45%.

Example 2

The amount of the bisazo-based dichroic dye used in example 1 was changed to 1g/L, and the rest was the same as in example 1, thereby obtaining a polarizing plate for a raincoat cap visor.

The polarizing degree of the polarizing film obtained was measured to be 75%, and the light transmittance was 47%.

Example 3

The baking temperature in the example 1 was changed to 70 ℃, and the rest was the same as that in the example 1, thereby obtaining the polarizing plate of the raincoat cap peak.

The polarizing degree of the obtained polarizing film was measured to be 70%, and the light transmittance was measured to be 43%.

Example 4

The amount of the bisazo-based dichroic dye used in example 1 was changed to 1g/L, the baking temperature was changed to 90 ℃, and the rest was the same as in example 1, thereby obtaining a polarizing plate for a raincoat cap visor.

The polarizing degree of the polarizing film obtained was measured to be 78%, and the light transmittance was measured to be 47%.

Comparative example 1

And ultrasonically cleaning the PVA film with the thickness of 60 mu m in absolute ethyl alcohol, and airing. And then, soaking the cleaned PVA film into 30g/L boric acid solution, carrying out crosslinking reaction at 70 ℃ for 5min, cleaning with deionized water for three times, and drying at 40 ℃ for 30 min. Dissolving 2g/L sodium alginate in 500L water, stirring, adding 0.5g/L bisazo type dichroic dye blue A-R (Lichangsheng dye technology), and stirring. The method comprises the steps of uniformly coating a coating color paste on a cleaned PVA film by adopting a suspension coating method, drying the coated PVA film for 30min at 40 ℃, slowly applying tension to the PVA in an environment with the temperature of 60 ℃ and the humidity of 100%, stretching the PVA by 4 times, and finishing dyeing of a dye to obtain the raincoat brim polaroid.

The polarizing degree of the polarizing film was 64% and the light transmittance was 40% by inspection

Comparative example 2

The baking temperature in the example 1 was changed to 100 ℃, and the rest was the same as that in the example 1, thereby obtaining a polarizing plate for a raincoat cap peak.

The polarizing degree of the obtained polarizing film was measured to be 60% and the light transmittance was measured to be 38%.

Claims

1. The utility model provides a raincoat brim of a hat polaroid which characterized in that, by drying behind the PVA membrane that mixed solution coating boric acid crosslinking of paste and dyestuff was handled, the steam fixation obtains, and wherein the mixed solution of paste and dyestuff includes 2 ~ 6g/L paste, 0.5 ~ 4g/L dyestuff and water, the technological parameter of steam fixation is: the temperature is 70-90 ℃, the stretching multiple is 2-5 times, and the humidity is 70-100%.

2. The polarizer of claim 1, wherein the paste is one of sodium alginate, sodium carboxymethyl starch, etherified vegetable gum, synthetic paste and emulsified paste.

3. The polarizer according to claim 1, wherein the dye is one of bisazo based polarizing dye, trisazo based polarizing dye, anthraquinone based dichroic dye, triphenyltriazine and derivative dichroic dye thereof, monomethine and polymethine based dichroic dye.

4. A preparation method of a polaroid of a raincoat brim comprises the following steps:

put into boric acid processing liquid with abluent PVA membrane in, carry out cross-linking treatment, later with the dye liquor coating, dry, the steam fixation, cooling, washing obtain raincoat brim of a hat polaroid, wherein boric acid concentration is 20 ~ 50g/L in the boric acid processing liquid, and the dye liquor includes: 2-6 g/L of paste, 0.5-4 g/L of dye and water, wherein the technological parameters of steam fixation are as follows: the temperature is 70-90 ℃, the stretching multiple is 2-5 times, and the humidity is 70-100%.

5. The method according to claim 4, wherein the crosslinking treatment temperature is 50 to 70 ℃, and the crosslinking treatment time is 3 to 8 min; the coating is a floating knife coating 1-2 layers.

6. The method according to claim 4, wherein the drying temperature is 40-60 ℃ and the drying time is 10-40 min.

7. Use of the polarizer of claim 1 in a raincoat visor.