Hot bending film for radian screen
Technical Field
The invention relates to the technical field of protective films, in particular to a hot bending film for a radian screen.
Background
With the development of information communication technology, smart phones have become essential in people's life. Most of the existing smart phones are touch screens, screens are easy to break or scratch, and the traditional mobile phone films cannot meet the requirements of people for a long time. In addition, the emergence of the arc-shaped frameless large-screen mobile phone puts forward higher requirements on a mobile phone protective film, the existing PET plane film cannot be perfectly attached to the arc-edge screen, and the existing protection has the defect that the arc-edge rebounds caused by high-low temperature circulation in the transportation and use processes, so that the existing protection cannot be exported.
Therefore, it is urgently required to develop a hot bending film for a curved panel capable of solving the above problems.
Disclosure of Invention
The invention provides a hot bending film for a radian screen, aiming at solving the defects and shortcomings of the prior art, and the hot bending film can avoid the phenomena of warping, setting failure, springback and the like of a rear film and can realize full lamination of the radian screen.
In order to achieve the purpose, the invention adopts the technical scheme that the hot bending film for the radian screen sequentially comprises a silica gel layer, a PET resin film layer, an OCA adhesive layer, a thermosetting acrylic resin containing film layer and a hardening layer from bottom to top.
The hot bending film disclosed by the invention can be well attached to a mobile phone screen and the like, the integral hot bending shrinkage rate is consistent, and the phenomena of film warping, setting failure, springback and the like after hot bending are avoided; the film can be prepared into a 2.5D, 3D or 4D hot bending film, and can be firmly attached to display screens with radian, such as mobile phone screens, tablet computer screens, television screens and the like.
As a preferable embodiment of the heat-bent film for a screen according to the present invention, the thickness of the thermosetting acrylic resin-containing film layer is 25 to 250. mu.m, for example, 30. mu.m, 35. mu.m, 40. mu.m, 45. mu.m, 50. mu.m, 55. mu.m, 70. mu.m, 90. mu.m, 120. mu.m, 150. mu.m, 200. mu.m, and 230. mu.m. Preferably 50 to 90 μm. The polyfunctional isocyanate in the film layer reacts with hydroxyl in the acrylic resin to form a cross-linked network, the film layer can be well attached to a mobile phone screen and the like, resilience is not easy to occur, the transmittance of the film layer is over 90%, and the film layer has good transparency.
As a preferred embodiment of the hot bending film for the arc screen, the raw materials for preparing the film layer containing thermosetting acrylic resin comprise acrylic resin and isocyanate;
preferably, the hydroxyl value of the acrylic resin is 20-150 mgKOH/g; the isocyanate has a functionality greater than 2;
preferably, the preparation raw materials further comprise an antifoaming agent, a leveling agent and a thickening agent.
In a preferred embodiment of the heat-bent film for a curved screen of the present invention, the acrylic resin has a hydroxyl value of 40 to 90mgKOH/g, and the isocyanate has a functionality of 3 to 4. In order to ensure the formation of a thermosetting resin cross-linked network system, a certain active group (hydroxyl group, the content of which is expressed by a hydroxyl value) is required in acrylic acid, the cross-linking degree is insufficient when the hydroxyl value is too low, the resin has too good toughness to qualitatively protect the film and inhibit the arc edge rebound of the protective film, the cross-linking degree is too high when the hydroxyl value is too high, the resin is too brittle, and the resin is easy to break when being attached to an arc edge screen.
As a preferred embodiment of the hot bending film for the arc screen, isocyanate and thermosetting acrylic resin are reacted, and the initial reaction temperature is 80-130 ℃, preferably 80-90 ℃. The use of the blocked isocyanate can control the crosslinking reaction, ensure that the protective film has enough toughness before the PET hot bending and shaping, but the initial temperature is not too high, otherwise, bubbles are easily generated in the protective film.
In a preferred embodiment of the heat bending film for a screen for a curved surface according to the present invention, the silica gel layer is a silicone pressure sensitive adhesive layer, and the silica gel layer has a thickness of 25 to 150 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 70 μm, 90 μm, or 120 μm, preferably 45 to 100 μm, and more preferably 25 to 60 μm.
As a preferred embodiment of the hot bending film for the arc screen, the PET resin film layer includes a first PET resin film layer and a second PET resin film layer, and the first PET resin film layer, the OCA adhesive layer, the thermosetting acrylic resin-containing film layer and the second PET resin film layer are respectively arranged from the right bottom to the top;
preferably, the thickness of the first PET resin film layer is 5-50 μm, and further preferably, the thickness of the first PET resin film layer is 10-30 μm;
preferably, the thickness of the second PET resin film layer is 25-250 μm, such as 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 70 μm, 90 μm, 120 μm, 150 μm, 200 μm, 230 μm, preferably 50-100 μm. Wherein, the PET resin film layer is too thin to be hardened, and the arc edge resilience force is increased due to too thick PET resin film layer.
In a preferred embodiment of the heat-bending film for a screen for a flat display according to the present invention, the thickness of the OCA adhesive layer is 25 to 200. mu.m, for example, 30. mu.m, 35. mu.m, 40. mu.m, 45. mu.m, 50. mu.m, 55. mu.m, 70. mu.m, 90. mu.m, 120. mu.m, preferably 25 to 75. mu.m.
As a preferred embodiment of the hot bending film for the arc screen, the thickness of the hardening layer is 2-10 μm, preferably 2-5 μm.
As a preferred embodiment of the hot bending film for the arc screen, the hot bending film further comprises a first protective film layer and a second protective film layer, wherein the first protective film layer is arranged at the lower end of the silica gel layer, and the second protective film layer is arranged at the upper end of the hardening layer;
preferably, the thickness of the first protective film is 25 to 150 μm, and more preferably 50 to 75 μm;
preferably, the peel strength of the first protective film layer is 0.1-1N/m according to GB2792, and preferably 0.3-0.7N/m;
preferably, the thickness of the second protective film is 25-150 μm, and further preferably 50-75 μm;
preferably, the second protective film layer has a peel strength of 0.3-5N/m, preferably 1-2N/m, according to GB 2792.
The invention has the beneficial effects that:
the hot bending film disclosed by the invention can be well attached to a mobile phone screen and the like, the integral hot bending shrinkage rate is consistent, and the phenomena of film warping, setting failure, springback and the like after hot bending are avoided; the heat-resistant anti-scratch film has the advantages of good wear resistance, good scratch resistance, good transparency, good temperature resistance and stable structure, can be prepared into a 2.5D, 3D or 4D hot bending film, and can be firmly attached to display screens with radian, such as mobile phone screens, tablet computer screens, television screens and the like.
Drawings
FIG. 1 is a schematic view showing a junction structure of a thermally bent film in example 1.
The protective film comprises 1-a first protective film, 2-a silica gel layer, 3-a first PET resin film layer, 4-an OCA glue layer, 5-a thermosetting acrylic resin film layer, 6-a second PET resin film layer, 7-a hardening layer and 8-a second protective film.
Detailed Description
To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.
Example 1
As an embodiment of the hot bending film for a radian screen, the hot bending film has a structure as shown in fig. 1, and sequentially comprises a first protective film 1, a silica gel layer 2, a first PET resin film layer 3, an OCA glue layer 4, a thermosetting acrylic resin-containing film layer 5, a second PET resin film layer 6, a hardened layer 7 and a second protective film 8 from bottom to top;
the thickness of the first protective film 1 is 50 μm, the thickness of the silica gel layer 2 is 25 μm, the thickness of the first PET resin film layer 3 is 5 μm, the thickness of the OCA glue layer 4 is 30 μm, the thickness of the thermosetting acrylic resin-containing film layer 5 is 30 μm, the thickness of the second PET resin film layer 6 is 25 μm, the thickness of the hardened layer 7 is 3 μm, and the thickness of the second protective film 8 is 50 μm.
Wherein the first protective film has a peel strength of 0.3N/m measured according to GB2792, the second protective film has a peel strength of 1N/m measured according to GB2792, and the silica gel layer 2 is an organosilicon pressure-sensitive adhesive layer.
The thermosetting acrylic resin-containing film layer 5 of this embodiment is prepared by reacting an acrylic resin having a hydroxyl value of 40mgKOH/g and a blocked isocyanate having a functionality of 2 as a crosslinking agent at an initial reaction temperature of 80 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by using the prior art.
And (3) superposing the layers according to the structure of the hot bending film to obtain the hot bending film, and performing the working procedures of die cutting, hot bending, curing and the like to obtain the target hot bending film product.
Example 2
As an embodiment of the hot bending film for a radian screen, the hot bending film has a structure as shown in fig. 1, and sequentially comprises a first protective film 1, a silica gel layer 2, a first PET resin film layer 3, an OCA glue layer 4, a thermosetting acrylic resin-containing film layer 5, a second PET resin film layer 6, a hardened layer 7 and a second protective film 8 from bottom to top;
the thickness of the first protective film 1 is 50 μm, the thickness of the silica gel layer 2 is 50 μm, the thickness of the first PET resin film layer 3 is 15 μm, the thickness of the OCA glue layer 4 is 40 μm, the thickness of the thermosetting acrylic resin-containing film layer 5 is 60 μm, the thickness of the second PET resin film layer 6 is 50 μm, the thickness of the hardened layer 7 is 3 μm, and the thickness of the second protective film 8 is 50 μm.
Wherein the first protective film has a peel strength of 0.5N/m measured according to GB2792, the second protective film has a peel strength of 1N/m measured according to GB2792, and the silica gel layer 2 is an organosilicon pressure-sensitive adhesive layer.
The thermosetting acrylic resin-containing film layer 5 of this embodiment is prepared by reacting an acrylic resin having a hydroxyl value of 60mgKOH/g and a blocked isocyanate having a functionality of 4 as a crosslinking agent at an initial reaction temperature of 90 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by using the prior art.
And (3) superposing the layers according to the structure of the hot bending film to obtain the hot bending film, and performing the working procedures of die cutting, hot bending, curing and the like to obtain the target hot bending film product.
Example 3
As an embodiment of the hot bending film for a radian screen, the hot bending film has a structure as shown in fig. 1, and sequentially comprises a first protective film 1, a silica gel layer 2, a first PET resin film layer 3, an OCA glue layer 4, a thermosetting acrylic resin-containing film layer 5, a second PET resin film layer 6, a hardened layer 7 and a second protective film 8 from bottom to top;
the thickness of the first protective film 1 is 50 μm, the thickness of the silica gel layer 2 is 75 μm, the thickness of the first PET resin film layer 3 is 15 μm, the thickness of the OCA glue layer 4 is 50 μm, the thickness of the thermosetting acrylic resin-containing film layer 5 is 90 μm, the thickness of the second PET resin film layer 6 is 75 μm, the thickness of the hardened layer 7 is 3 μm, and the thickness of the second protective film 8 is 50 μm.
Wherein the first protective film has a peel strength of 0.7N/m measured according to GB2792, the second protective film has a peel strength of 2N/m measured according to GB2792, and the silica gel layer 2 is an organosilicon pressure-sensitive adhesive layer.
The thermosetting acrylic resin-containing film layer 5 of this embodiment is prepared by reacting acrylic resin having a hydroxyl value of 90mgKOH/g and blocked isocyanate having a functionality of 4 as a crosslinking agent at an initial reaction temperature of 90 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by using the prior art.
And (3) superposing the layers according to the structure of the hot bending film to obtain the hot bending film, and performing the working procedures of die cutting, hot bending, curing and the like to obtain the target hot bending film product.
Example 4
As an embodiment of the hot bending film for a radian screen, the hot bending film has a structure as shown in fig. 1, and sequentially comprises a first protective film 1, a silica gel layer 2, a first PET resin film layer 3, an OCA glue layer 4, a thermosetting acrylic resin-containing film layer 5, a second PET resin film layer 6, a hardened layer 7 and a second protective film 8 from bottom to top;
the thickness of the first protective film 1 is 50 μm, the thickness of the silica gel layer 2 is 100 μm, the thickness of the first PET resin film layer 3 is 10 μm, the thickness of the OCA glue layer 4 is 75 μm, the thickness of the thermosetting acrylic resin-containing film layer 5 is 120 μm, the thickness of the second PET resin film layer 6 is 100 μm, the thickness of the hardened layer 7 is 3 μm, and the thickness of the second protective film 8 is 50 μm.
Wherein the first protective film has a peel strength of 1N/m measured according to GB2792, the second protective film has a peel strength of 5N/m measured according to GB2792, and the silica gel layer 2 is an organosilicon pressure-sensitive adhesive layer.
The thermosetting acrylic resin-containing film layer 5 of this embodiment is prepared by reacting an acrylic resin having a hydroxyl value of 120mgKOH/g and a blocked isocyanate having a functionality of 4 as a crosslinking agent at an initial reaction temperature of 100 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by using the prior art.
And (3) superposing the layers according to the structure of the hot bending film to obtain the hot bending film, and performing the working procedures of die cutting, hot bending, curing and the like to obtain the target hot bending film product.
Example 5
As an embodiment of the hot bending film for a radian screen, the hot bending film has a structure as shown in fig. 1, and sequentially comprises a first protective film 1, a silica gel layer 2, a first PET resin film layer 3, an OCA glue layer 4, a thermosetting acrylic resin-containing film layer 5, a second PET resin film layer 6, a hardened layer 7 and a second protective film 8 from bottom to top;
the thickness of the first protective film 1 is 30 μm, the thickness of the silica gel layer 2 is 25 μm, the thickness of the first PET resin film layer 3 is 30 μm, the thickness of the OCA glue layer 4 is 25 μm, the thickness of the thermosetting acrylic resin-containing film layer 5 is 25 μm, the thickness of the second PET resin film layer 6 is 100 μm, the thickness of the hardened layer 7 is 2 μm, and the thickness of the second protective film 8 is 30 μm.
Wherein the first protective film has a peel strength of 0.1N/m measured according to GB2792, the second protective film has a peel strength of 0.3N/m measured according to GB2792, and the silica gel layer 2 is an organosilicon pressure-sensitive adhesive layer.
The thermosetting acrylic resin-containing film layer 5 of this embodiment is prepared by reacting acrylic resin having a hydroxyl value of 30mgKOH/g and blocked isocyanate having a functionality of 4 as a crosslinking agent at an initial reaction temperature of 100 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by using the prior art.
And (3) superposing the layers according to the structure of the hot bending film to obtain the hot bending film, and performing the working procedures of die cutting, hot bending, curing and the like to obtain the target hot bending film product.
Example 6
As an embodiment of the hot bending film for a radian screen, the hot bending film has a structure as shown in fig. 1, and sequentially comprises a first protective film 1, a silica gel layer 2, a first PET resin film layer 3, an OCA glue layer 4, a thermosetting acrylic resin-containing film layer 5, a second PET resin film layer 6, a hardened layer 7 and a second protective film 8 from bottom to top;
the thickness of the first protective film 1 is 130 μm, the thickness of the silica gel layer 2 is 120 μm, the thickness of the first PET resin film layer 3 is 50 μm, the thickness of the OCA glue layer 4 is 200 μm, the thickness of the thermosetting acrylic resin-containing film layer 5 is 230 μm, the thickness of the second PET resin film layer 6 is 230 μm, the thickness of the hardened layer 7 is 2 μm, and the thickness of the second protective film 8 is 130 μm.
Wherein the first protective film has a peel strength of 1N/m measured according to GB2792, the second protective film has a peel strength of 5N/m measured according to GB2792, and the silica gel layer 2 is an organosilicon pressure-sensitive adhesive layer.
The thermosetting acrylic resin-containing film layer 5 of this embodiment is prepared by reacting an acrylic resin having a hydroxyl value of 150mgKOH/g and a blocked isocyanate having a functionality of 4 as a crosslinking agent at an initial reaction temperature of 130 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by using the prior art.
And (3) superposing the layers according to the structure of the hot bending film to obtain the hot bending film, and performing the working procedures of die cutting, hot bending, curing and the like to obtain the target hot bending film product.
Comparative example 1
This comparative example is different from example 2 only in that the film layer containing a thermosetting acrylic resin film layer 5 has a thickness of 20 μm.
Comparative example 2
This comparative example is different from example 2 only in that the film layer containing a thermosetting acrylic resin film layer 5 has a thickness of 300 μm.
Comparative example 3
The difference between this comparative example and example 2 is only that the thermosetting acrylic resin containing film layer 5 of this example is prepared by reacting acrylic resin with hydroxyl value of 10mgKOH/g and isocyanate with functionality of 4 as a cross-linking agent, the initial reaction temperature is 90 ℃, and then adding a defoaming agent, a leveling agent, and a thickening agent, and the preparation method can be realized by adopting the prior art.
Comparative example 4
The difference between the comparative example and example 2 is only that the thermosetting acrylic resin containing film layer 5 of this example is prepared by reacting acrylic resin with hydroxyl value of 200mgKOH/g and blocked isocyanate with functionality of 4 as a cross-linking agent, the initial reaction temperature is 90 ℃, and then adding a defoaming agent, a leveling agent and a thickening agent, and the preparation method can be realized by adopting the prior art.
Comparative example 5
The difference between the comparative example and example 2 is only that the thermosetting acrylic resin containing film layer 5 of this example is prepared by reacting acrylic resin with hydroxyl value of 60mgKOH/g and blocked isocyanate with functionality of 2 as a cross-linking agent, the initial reaction temperature is 150 ℃, and then adding an antifoaming agent, a leveling agent and a thickening agent, and the preparation method can be realized by adopting the prior art.
Comparative example 6
The difference between the comparative example and example 2 is that the thermosetting acrylic resin-containing film layer 5 of this example is prepared by reacting an acrylic resin having a hydroxyl value of 60mgKOH/g with isocyanate having a functionality of 4 as a crosslinking agent at an initial reaction temperature of 150 ℃, and adding an antifoaming agent, a leveling agent, and a thickening agent, and the preparation method can be implemented by the prior art.
Example 7
The hot bending films obtained in examples 1 to 6 and comparative examples 1 to 6 were subjected to a thermal cycle test to observe the arc edge rebound condition, and the thermal cycle test conditions were as follows: the temperature is changed at the speed of 10 ℃/min under the temperature of minus 20 to 90 ℃, and the testing time is 72 hours; and testing the influence of resilience on the bonding firmness of the protective film. The test results are shown in table 1.
TABLE 1
The results show that the hot-bending films obtained in examples 1 to 6 are firmly attached to the screen, have no rebound and have good performance. The thickness of the thermosetting acrylic resin-containing film layer of the hot-bending film of the comparative examples 1-2 is outside the range of the invention, the full lamination with the radian display screen can be influenced by too thick or too thin the thickness, the preparation raw materials and the preparation process parameters of the thermosetting acrylic resin-containing film layer of the comparative examples 3-6 are outside the range of the invention, wherein the hydroxyl value of the acrylic acid of the comparative examples 3-4 is outside the range of the invention, and the hydroxyl value of the acrylic acid can influence the performance of the hot-bending film. In comparative examples 5 to 6, the isocyanate functionality was 2 and the initial reaction temperature was 150 ℃, and it can be seen from the results that the initial temperature was not too high and bubbles were easily generated in the protective film.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.