High-definition white-fog-free pc protective film and preparation method thereof

Abstract

The application discloses a high-definition white-fog-free PC protective film and a preparation method thereof, which is prepared from polycarbonate, amorphous polyester polyol, a second solvent, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), a chain extender, a moisture-resistant auxiliary agent, a catalyst, a curing agent and a solvent. The high-definition white-fog-free PC protective film is obtained through a large number of experiments, the PC protective film effectively avoids light scattering caused by crystallization, inhibits the invasion of water vapor, has high light transmittance and low haze, has excellent high-temperature and high-humidity resistance, light stability and weather resistance, and has low price cost, so that the PC protective film is beneficial to popularization and application in the high-end screen protection field and can overcome many defects of the prior art.

Description

Technical Field

[0001] This invention belongs to the field of electronic product applications, specifically relating to a high-definition, fog-free PC protective film and its preparation method. Background Technology

[0002] With the rapid development of electronic products such as mobile phones and computers, high-transparency and high-definition protective films have been widely used. Currently, the vast majority of protective films on the market are made of PET substrate coated with acrylic adhesive, polyurethane adhesive, or silicone pressure-sensitive adhesive. High-end protective films in the domestic market usually use imported high-definition PET, which is not only expensive but also has a high haze (0.5%-3%). In terms of the coating material, acrylic adhesive has poor air release properties and is rarely used in the screen protection field. Silicone pressure-sensitive adhesive and polyurethane adhesive are prone to white fogging in high temperature and high humidity environments, which has become a common problem in the industry. The reasons are as follows: First, low molecular weight components exist in the pressure-sensitive adhesive in a free form when not fully cross-linked. Under long-term use or high temperature environment (>60 degrees Celsius), low molecular weight substances will migrate to the surface, forming white or foggy precipitation. Second, unreacted isocyanate groups (-NCO) in isocyanate adhesive react with moisture (H2O) in the environment to produce amines and carbon dioxide gas. In addition, the hydrolysis reaction of polyester polyurethane also produces acids and alcohols. The small molecules produced in both situations cause white haze-like substances to appear inside and on the surface of the polyurethane adhesive, leading to an increase in haze. In recent years, the quality requirements of high-end electronic products have been continuously increasing, and consumers are pursuing the ultimate experience. In fields such as high-definition cameras, AR glasses, astronomical telescopes, and automotive screens, there is an urgent need for a high-definition, low-haze, high-temperature and high-humidity resistant, and residue-free protective film. Therefore, research on a high-definition, haze-free PC protective film and its preparation method is particularly urgent! Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a high-definition, fog-free PC protective film and its preparation method, thereby solving the problems of high haze and easy formation of white fog under high temperature and humidity environments in existing electronic product protective film technologies.

[0004] According to the technical solution of the present invention, the high-definition, fog-free PC protective film includes: a substrate layer, a polyurethane pressure-sensitive adhesive layer, and a release layer.

[0005] The substrate layer is the base of the high-definition, fog-free PC protective film. The substrate layer is made of polycarbonate (PC) film with a transmittance >92% and a haze <0.3%.

[0006] The polyurethane pressure-sensitive adhesive layer is disposed above the substrate layer. The material components of the polyurethane pressure-sensitive adhesive layer include: modified polyurethane adhesive, curing agent and solvent. By weight, the material component ratio of the polyurethane pressure-sensitive adhesive layer is: 80-120 parts of modified polyurethane adhesive, 3-6 parts of curing agent and 40-80 parts of first solvent.

[0007] The modified polyurethane adhesive comprises the following materials: amorphous polyester polyol, a second solvent, isoflurane diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), chain extender, moisture-resistant additive, and catalyst. By weight, the proportions of the modified polyurethane adhesive are: 30-50 parts amorphous polyester polyol, 10-30 parts solvent, 6-8 parts isoflurane diisocyanate (IPDI), 2-4 parts hexamethylene diisocyanate (HMDI), 2-3 parts chain extender, 1-2 parts moisture-resistant additive, and 0.1-0.3 parts catalyst.

[0008] The modified polyurethane adhesive is prepared by placing 30-50 parts of the amorphous polyester polyol into a reaction vessel and stirring at a constant speed of 800 r / min. The reaction temperature is controlled by a temperature control system to rise at a constant speed and maintained at 105-125℃. Vacuum dehydration is carried out for 1-2 hours. When the water content of the amorphous polyester polyol is <0.03%, nitrogen gas is introduced and the temperature is lowered to 25℃. Then, 6-8 parts of isoflurane diisocyanate (IPDI) and 2-4 parts of hexamethylene diisocyanate (HMDI) are added to the reaction vessel. The reaction temperature is controlled to rise at a constant speed. When the reaction temperature rises to 80℃, 0.1-0.3 parts of catalyst are added and the reaction is carried out for 2 hours. Finally, 2-3 parts of chain extender and 1-2 parts of moisture-resistant additive are added to the reaction vessel and the reaction is continued for 1 hour to obtain the modified polyurethane adhesive.

[0009] The amorphous polyester polyol is selected from conventional amorphous polyester polyols.

[0010] Preferably, the number average molecular weight of the amorphous polyester polyol is between 1000 and 8000.

[0011] Preferably, the amorphous polyester polyol is Hanhai ULTRAOLS P-1000, but it is not limited to this specification; other specifications are also within the selection range.

[0012] The chain extender is conventional 1,4-butanediol (BDO).

[0013] The moisture-resistant additive is selected from any one of 3-hydroxyethyl-1, 3-oxazolidine, 2-isopropyl-3-hydroxyethyl-1, and 3-oxazolidine additives.

[0014] The catalyst used is conventional dibutyltin dilaurate.

[0015] The curing agent is selected from at least one of polyisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and isoflurone diisocyanate.

[0016] The first solvent and the second solvent are toluene or ethyl acetate.

[0017] The release film is one of the following: an organosilicon release film, a non-silicone release film, or a fluorine release film.

[0018] The method for preparing a high-definition, fog-free PC protective film includes the following steps: S1: Mix 80-120 parts of the modified polyurethane adhesive, 40-80 parts of the first solvent, and 3-6 parts of the curing agent and add them to the reaction vessel. Stir at a constant speed of 800 r / min for 30 min to prepare a polyurethane pressure-sensitive adhesive liquid.

[0019] S2: Using specialized coating equipment such as a slot die, the polyurethane pressure-sensitive adhesive is uniformly coated onto the polycarbonate (PC) film substrate layer. The polyurethane pressure-sensitive adhesive-coated polyurethane film substrate layer is then subjected to oven drying at a constant temperature of 110°C for 3 minutes. After drying, the polyurethane pressure-sensitive adhesive layer of the high-definition, white-haze-free PC protective film is prepared. S3: Using a release film composite process, the release film is laminated onto the polyurethane pressure-sensitive adhesive layer to complete the attachment of the release film. Finally, it is cured at 40°C for 7 days to obtain the high-definition, fog-free PC protective film.

[0020] The technical solution of the present invention has the following advantages compared with the existing technical solutions: (1) In the preparation of the modified polyurethane adhesive, the present invention introduces the amorphous polyester diol. The amorphous polyester diol has a glass transition temperature of <-15℃, no crystalline region, soft molecular chains, and high disorder of chain segment arrangement between molecules. This realizes the molecular structure optimization design of traditional polyurethane adhesives, which can effectively avoid light scattering caused by crystallization, so that the colloid transmittance reaches more than 92% and the haze is less than 0.3%.

[0021] (2) The modified polyurethane adhesive of the present invention adopts a synergistic curing system of isoflurane diisocyanate (IPDI) and hexamethylene diisocyanate (HMDI). The alicyclic groups in the molecular structure of isoflurane diisocyanate (IPDI) provide excellent resistance to yellowing, while the benzene ring structure in hexamethylene diisocyanate (HMDI) has excellent light stability and weather resistance. The synergistic effect of the two curing agents jointly improves the weather resistance of the adhesive. The oxazolidine moisture-resistant additive is a nitrogen-containing heterocyclic compound that will open its ring and react with water when exposed to moisture to generate amino and hydroxyl groups, and then quickly crosslink with the isocyanate groups without releasing carbon dioxide gas. It can effectively improve the weather resistance while increasing the crosslinking density and further inhibit the intrusion of water vapor.

[0022] (3) The high-definition, fog-free PC protective film of the present invention has the advantages of high light transmittance (transmittance > 92%) and extremely low fog (fog < 0.3%). At the same time, it has excellent high temperature and high humidity resistance and has obvious advantages in the field of high-end screen protection. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a high-definition, fog-free PC protective film according to the present invention.

[0024] Among them, 1-substrate layer (PC), 2-polyurethane pressure-sensitive adhesive layer, 3-release layer. Detailed Implementation

[0025] This invention discloses a high-definition, fog-free PC protective film and its preparation method. To make the technical means, creative features, objectives, and effects of this invention easier to understand, the invention is further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only for illustrating the invention and not for limiting the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

[0026] The reagents, models, and manufacturers used in the following specific embodiments and comparative examples are shown in the table below:

[0027] Example 1 The high-definition, fog-free PC protective film prepared in this embodiment has the following material composition ratio in the polyurethane pressure-sensitive adhesive layer by weight: 80 parts modified polyurethane adhesive, 3 parts curing agent, and 40 parts first solvent.

[0028] Preferably, the modified polyurethane adhesive has the following material composition ratio by weight: 30 parts amorphous polyester polyol, 6 parts isoflurane diisocyanate (IPDI), 2 parts hexamethylene diisocyanate (HMDI), 0.1 parts catalyst, 2 parts chain extender, and 1 part moisture-resistant additive.

[0029] Preferably, the modified polyurethane adhesive is prepared by placing 30 parts of the amorphous polyester polyol into a reaction vessel, stirring at a constant speed of 800 r / min, controlling the reaction temperature to rise at a constant speed through a temperature control system, maintaining it at 105°C, and vacuum dehydrating for 1-2 hours. When the water content of the amorphous polyester polyol is <0.03%, nitrogen gas is introduced as a protective gas and the temperature is lowered to 25°C. Then, 6 parts of isoflurane diisocyanate (IPDI) and 2 parts of hexamethylene diisocyanate (HMDI) are mixed and added into the reaction vessel, controlling the reaction temperature to rise at a constant speed. When the reaction temperature rises to 80°C, 0.1 parts of catalyst are added, and the reaction is carried out for 2 hours. Finally, 2 parts of chain extender and 1 part of moisture-resistant additive are mixed and added into the reaction vessel, and the reaction is continued for 1 hour to obtain the modified polyurethane adhesive.

[0030] The method for preparing a high-definition, fog-free PC protective film includes the following steps: S1: Mix 80 parts of the modified polyurethane adhesive, 40 parts of the first solvent, and 3 parts of the curing agent and add them to the reaction vessel. Stir at a constant speed of 800 r / min for 30 min to prepare a polyurethane pressure-sensitive adhesive liquid.

[0031] S2: Using specialized coating equipment such as a slot die, the polyurethane pressure-sensitive adhesive is uniformly coated onto the polycarbonate (PC) film substrate layer. The polyurethane pressure-sensitive adhesive-coated polyurethane film substrate layer is then subjected to oven drying at a constant temperature of 110°C for 3 minutes. After drying, the polyurethane pressure-sensitive adhesive layer of the high-definition, white-haze-free PC protective film is prepared. S3: Using a release film composite process, the release film is laminated onto the polyurethane pressure-sensitive adhesive layer to complete the attachment of the release film. Finally, it is cured at 40°C for 7 days to obtain the high-definition, fog-free PC protective film. Example

[0032] The high-definition, fog-free PC protective film prepared in this embodiment has the following material composition ratio in the polyurethane pressure-sensitive adhesive layer by weight: 100 parts modified polyurethane adhesive, 4.5 parts curing agent, and 60 parts first solvent.

[0033] Preferably, the modified polyurethane adhesive has the following material composition ratio by weight: 40 parts amorphous polyester polyol, 7 parts isoflurane diisocyanate (IPDI), 3 parts hexamethylene diisocyanate (HMDI), 0.2 parts catalyst, 2.5 parts chain extender, and 1.5 parts moisture-resistant additive.

[0034] Preferably, the modified polyurethane adhesive is prepared by placing 40 parts of the amorphous polyester polyol into a reaction vessel, stirring at a constant speed of 800 r / min, controlling the reaction temperature to rise at a constant speed through a temperature control system, maintaining it at 115°C, and vacuum dehydrating for 1-2 hours. When the water content of the amorphous polyester polyol is <0.03%, a protective gas of nitrogen is introduced and the temperature is lowered to 25°C. Then, 7 parts of isoflurane diisocyanate (IPDI) and 3 parts of hexamethylene diisocyanate (HMDI) are mixed and added into the reaction vessel, controlling the reaction temperature to rise at a constant speed. When the reaction temperature rises to 80°C, 0.2 parts of catalyst are added, and the reaction is carried out for 2 hours. Finally, 2.5 parts of chain extender and 1.5 parts of moisture-resistant additive are mixed and added into the reaction vessel, and the reaction is continued for 1 hour to obtain the modified polyurethane adhesive.

[0035] The method for preparing a high-definition, fog-free PC protective film includes the following steps: S1: Mix 100 parts of the modified polyurethane adhesive, 60 parts of the first solvent, and 4.5 parts of the curing agent and add them to the reaction vessel. Stir at a constant speed of 800 r / min for 30 min to prepare a polyurethane pressure-sensitive adhesive liquid.

[0036] S2: Using specialized coating equipment such as a slot die, the polyurethane pressure-sensitive adhesive is uniformly coated onto the polycarbonate (PC) film substrate layer. The polyurethane pressure-sensitive adhesive-coated polyurethane film substrate layer is then subjected to oven drying at a constant temperature of 110°C for 3 minutes. After drying, the polyurethane pressure-sensitive adhesive layer of the high-definition, white-haze-free PC protective film is prepared. S3: Using a release film composite process, the release film is laminated onto the polyurethane pressure-sensitive adhesive layer to complete the attachment of the release film. Finally, it is cured at 40°C for 7 days to obtain the high-definition, fog-free PC protective film. Example

[0037] The high-definition, fog-free PC protective film prepared in this embodiment has the following material composition ratio in the polyurethane pressure-sensitive adhesive layer by weight: 120 parts modified polyurethane adhesive, 6 parts curing agent, and 80 parts first solvent.

[0038] Preferably, the modified polyurethane adhesive has the following material composition ratio by weight: 30-50 parts of amorphous polyester polyol, 8 parts of isoflurane diisocyanate (IPDI), 4 parts of hexamethylene diisocyanate (HMDI), 0.3 parts of catalyst, 3 parts of chain extender, and 2 parts of moisture-resistant additive.

[0039] Preferably, the modified polyurethane adhesive is prepared by placing 30-50 parts of the amorphous polyester polyol into a reaction vessel, stirring at a constant speed of 800 r / min, controlling the reaction temperature to rise at a constant speed through a temperature control system, maintaining it at 125°C, and vacuum dehydrating for 1-2 hours. When the water content of the amorphous polyester polyol is <0.03%, nitrogen gas is introduced as a protective gas and the temperature is lowered to 25°C. Then, 8 parts of isoflurane diisocyanate (IPDI) and 4 parts of hexamethylene diisocyanate (HMDI) are mixed and added into the reaction vessel, controlling the reaction temperature to rise at a constant speed. When the reaction temperature rises to 80°C, 0.3 parts of catalyst are added, and the reaction is carried out for 2 hours. Finally, 3 parts of chain extender and 2 parts of moisture-resistant additive are mixed and added into the reaction vessel, and the reaction is continued for 1 hour to obtain the modified polyurethane adhesive.

[0040] The method for preparing a high-definition, fog-free PC protective film includes the following steps: S1: Mix 120 parts of the modified polyurethane adhesive, 80 parts of the first solvent, and 6 parts of the curing agent and add them to the reaction vessel. Stir at a constant speed of 800 r / min for 30 min to prepare a polyurethane pressure-sensitive adhesive liquid.

[0041] S2: Using specialized coating equipment such as a slot die, the polyurethane pressure-sensitive adhesive is uniformly coated onto the polycarbonate (PC) film substrate layer. The polyurethane pressure-sensitive adhesive-coated polyurethane film substrate layer is then subjected to oven drying at a constant temperature of 110°C for 3 minutes. After drying, the polyurethane pressure-sensitive adhesive layer of the high-definition, white-haze-free PC protective film is prepared. S3: Using a release film composite process, the release film is laminated onto the polyurethane pressure-sensitive adhesive layer to complete the attachment of the release film. Finally, it is cured at 40°C for 7 days to obtain the high-definition, fog-free PC protective film. Example

[0042] It is basically the same as Example 1, except that the modified polyurethane adhesive is 120 parts. Example

[0043] It is basically the same as Example 1, except that the chain extender is 3 parts. Example

[0044] It is basically the same as Example 1, except that there are 2 parts of the moisture-resistant additive.

[0045] Comparative Example 1 It is basically the same as Example 1, except that the amorphous polyester polyol is replaced with a crystalline polyester polyol.

[0046] Comparative Example 2 It is basically the same as Example 1, except that the amorphous polyester polyol is replaced with a polyether polyol.

[0047] Comparative Example 3 It is basically the same as Example 1, except that the hexamethylene diisocyanate (HMDI) is not added.

[0048] Comparative Example 4 It is basically the same as Example 1, except that the moisture-resistant additive is not added.

[0049] Performance testing Peel strength test refers to GB / T 2792-2014, haze and transmittance test refers to GB / T 2410-2008, high temperature and high humidity resistance test: peel off the release film of the PC protective film and stick it on the glass screen surface. After placing it under high temperature and high humidity (85℃ / 85% humidity) conditions for 7 days, take it out and test the haze and transmittance, and observe whether there is white haze and residual adhesive on the glass surface.

[0050] The test data is shown in the table below:

[0051] Comparing the above embodiments and comparative examples, the high-definition, fog-free PC protective film prepared by this technical solution has a transmittance >92%, a haze <0.3%, no white fog or residue after high temperature and humidity, and stable performance, achieving the expected results overall. Test data from Comparative Examples 1 and 2 show that when the synthetic raw materials of the modified polyurethane adhesive are changed to crystalline polyester polyol or polyether polyol, the PC protective film has higher haze and lower transmittance, and the latter will show residue points after high temperature and humidity testing, both of which are detrimental to practical applications. Comparison of Example 1 and Comparative Example 3 shows that when the polyurethane pressure-sensitive adhesive uses a dual-system curing agent of isoflurone diisocyanate (IPDI) and hexamethylene diisocyanate (HMDI), it has better high temperature and humidity resistance. Comparative Example 4 shows that when the polyurethane pressure-sensitive adhesive uses a formulation without the added moisture-resistant additive, the haze increases sharply after high temperature and humidity testing, and severe white fog remains on the screen surface, which is detrimental to production applications.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the preparation methods defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the preparation methods and novel features disclosed herein.

Claims

1. A high-definition, fog-free PC protective film is characterized in that it is composed of a substrate layer, a polyurethane pressure-sensitive adhesive layer and a release layer, wherein the polyurethane pressure-sensitive adhesive is made from the following raw materials in the specified proportions: 80-120 parts of modified polyurethane adhesive, 3-6 parts of curing agent, and 40-80 parts of first solvent.

2. The modified polyurethane adhesive according to claim 1 is characterized in that: It is made from the following raw materials in the following proportions: 30-50 parts of amorphous polyester polyol, 10-30 parts of solvent, 6-8 parts of isoflurane diisocyanate (IPDI), 2-4 parts of hexamethylene diisocyanate (HMDI), 2-3 parts of chain extender, 1-2 parts of moisture-resistant additive, and 0.1-0.3 parts of catalyst.

3. The method for preparing the modified polyurethane adhesive according to claim 2, characterized in that, Includes the following steps: 30-50 parts of the amorphous polyester polyol were placed in a reactor and stirred at a constant speed of 800 r / min. The reaction temperature was controlled by a temperature control system to rise at a constant speed and maintained at 105-125℃. Vacuum dehydration was carried out for 1-2 hours. When the water content of the amorphous polyester polyol was <0.03%, nitrogen gas was introduced and the temperature was lowered to 25℃. Then, 6-8 parts of isoflurane diisocyanate (IPDI) and 2-4 parts of hexamethylene diisocyanate (HMDI) were added to the reactor. The reaction temperature was controlled to rise at a constant speed. When the reaction temperature rose to 80℃, 0.1-0.3 parts of catalyst were added and the reaction was carried out for 2 hours. Finally, 2-3 parts of chain extender and 1-2 parts of moisture-resistant additive were added to the reactor and the reaction was continued for 1 hour to obtain the modified polyurethane adhesive.

4. The amorphous polyester polyol according to claim 2, characterized in that: Its number-average molecular weight is between 1,000 and 8,000.

5. The moisture-resistant additive according to claim 2, characterized in that: It can be selected from any one of the following adjuvants: 3-hydroxyethyl-1, 3-oxazolidine, 2-isopropyl-3-hydroxyethyl-1, and 3-oxazolidine.

6. The curing agent according to claim 1, characterized in that: It selects at least one of polyisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and isoflurone diisocyanate.

7. The high-definition, fog-free PC protective film and its preparation method according to claim 1, characterized in that, Includes the following steps: S1: Mix 80-120 parts of the modified polyurethane adhesive, 40-80 parts of the first solvent, and 3-6 parts of the curing agent and add them to the reaction vessel. Stir at a constant speed of 800 r / min for 30 min to prepare a polyurethane pressure-sensitive adhesive liquid. S2: Using specialized coating equipment such as a slot die, the polyurethane pressure-sensitive adhesive liquid is uniformly coated onto the polycarbonate (PC) film substrate layer. The polycarbonate (PC) film substrate layer coated with the polyurethane pressure-sensitive adhesive liquid is then subjected to oven constant temperature drying treatment. The drying temperature is set to 110℃ and the drying time is set to 3min. After the drying treatment is completed, the polyurethane pressure-sensitive adhesive layer of the high-definition, white-fog-free PC protective film is prepared. S3: Using a release film composite process, the release film is laminated onto the polyurethane pressure-sensitive adhesive layer to complete the attachment of the release film. Finally, it is cured at 40°C for 7 days to obtain the high-definition, fog-free PC protective film.

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