WO2022062245A1 - High transparent tpu film for electronic products and preparation method therefor - Google Patents

Abstract

The present invention provides a high transparent TPU film for electronic products and a preparation method therefor. The raw materials for preparing the high transparent TPU film for electronic products comprise the following components in parts by weight: 45-55 parts of polyester polyol, 3-10 parts of polyethylene glycol, 1-5 parts of fluorine-containing polyol, 25-35 parts of isophorone diisocyanate, 5-10 parts of chain extender, 1-5 parts of modified graphene oxide, 1-5 parts of modified porous silicon dioxide, and 0.1-0.5 part of catalyst. The TPU film material of the present invention also has relatively low roughness and good mechanical properties while having excellent transparency, and is more suitable for the protection of electronic products.

Description

A kind of high transparent TPU film for electronic products and preparation method thereof

The present disclosure is based on the Chinese patent application with the application number of 202011002031.2 and the filing date of September 22, 2020, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is incorporated herein by reference.

technical field

The invention belongs to the technical field of polymer materials, in particular to a TPU film and a preparation method thereof, in particular to a high-transparency TPU film for electronic products and a preparation method thereof.

Background technique

Thermoplastic polyurethane (TPU) is a new type of organic polymer synthetic material with excellent properties, which can replace rubber and soft polyvinyl chloride material PVC. For example, it has excellent physical properties, such as abrasion resistance and resilience, which are better than ordinary polyurethane and PVC, and its aging resistance is better than rubber. It can be said that it is the most ideal material to replace PVC and PU. At present, commercially available TPU materials generally have shortcomings such as poor heat resistance and insufficient transparency. Long-term exposure to high temperature environments is prone to deterioration, and at the same time, yellowing occurs, which affects the normal use and function of the film.

CN104262937A discloses a high-transparency TPU film for keyboard film, which by mass percentage contains 5-20% of PP particles; 40-80% of TPU particles; 5-20% of epoxy resin; phosphite without benzene ring 1 -5%; maleic anhydride graft copolymer polypropylene 1-5%; UV absorber 1-5%; hydrogen-containing silicone oil 1-5%. The invention improves the transparency and mechanical properties of the TPU film, but its transparency drops sharply under long-term exposure, and the mechanical properties also weaken.

CN110481131A provides and discloses a high-transparency polyether type double-mirror TPU film, including a TPU film body, and the top and bottom of the TPU film body are provided with tear-proof layers. The present invention is provided with a tear-proof layer, a transparent vulcanized rubber layer, a transparent thermoplastic rubber layer, a transparent polyolefin layer, a flame retardant layer, a transparent flame retardant silicone rubber layer, a transparent flame retardant magnesium oxide layer, a transparent flame retardant polyamide layer, and a flame retardant layer. The corrosion layer, the transparent phenolic plastic layer, the transparent epoxy resin layer and the transparent polyisobutylene rubber layer cooperate with each other to improve the tear resistance of the TPU film. Although the TPU film is made of highly transparent material for each layer, its transparency is related to the purity and uniformity of the medium. Too many layers will cause the transparency to drop sharply after long-term exposure, which cannot meet the application requirements in the technical field of some electronic products.

Therefore, the development of a highly transparent TPU film with excellent mechanical properties is the focus of research in the field of electronic products.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the purpose of the present invention is to provide a transparent TPU film and a preparation method thereof, in particular to provide a highly transparent TPU film for electronic products and a preparation method thereof. The TPU film material described in this application has extremely high transparency and excellent mechanical properties. In particular, "high transparency" in the present invention means that the light transmittance is above 97%.

For this purpose, the present invention adopts the following technical solutions:

In the first aspect, the present invention provides a high-transparency TPU film for electronic products, and the preparation raw materials of the high-transparency TPU film for electronic products include the following components in parts by weight:

In the present invention, polyester polyol and isophorone diisocyanate are used as main raw materials to synthesize polyurethane, and an appropriate proportion of polyethylene glycol is introduced into the polyurethane segment, and the hard and soft segments in the polyurethane segment can form a more suitable The microphase separation structure increases the content force of the rigid segment, thereby improving the tensile strength and elongation of the film. In addition, the introduction of fluorine-containing polyols is end-capped with fluorine to obtain double cross-linked polyurethane, which endows the film with excellent optical transparency and flexibility due to the good compatibility of the fluorine-containing polyol with the polyurethane segment and the small roughness of the film. and the introduction of fluorine as a hydrophobic segment, endows the film with better self-cleaning and anti-adhesion properties.

In addition, the present invention introduces modified graphene oxide to modify the polyurethane, which can react with polyols and isocyanates, and can act as the hard segment of TPU, so that a part of chemical cross-linking structure is formed between molecules, and the mechanical properties of the material are improved. The introduction of modified porous silica can form hydrogen bonds or generate van der Waals forces due to the presence of a large number of hydroxyl groups on the surface of porous silica materials. It is the hydroxyl group on silanol that plays an adsorption role in the TPU system, which constitutes the adsorption center. These adsorbents have a huge surface area and pore volume, so they have a good ability to adsorb polar impurities, and the metal ions in the modified polyurethane system can be on the surface of the adsorbent, thereby further improving the light transmittance of the TPU film.

In the present invention, the weight part of polyester polyol is 45-55 parts, for example, it can be 45 parts, 46 parts, 47 parts, 48 parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts servings, 55 servings, etc.

In the present invention, the weight part of polyethylene glycol is 3-10 parts, for example, it can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

In the present invention, the weight part of the fluorine-containing polyol is 1-5 parts, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

In the present invention, the weight part of isophorone diisocyanate is 25-35 parts, for example, it can be 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts , 34 copies, 35 copies, etc.

In the present invention, the weight part of the chain extender is 5-10 parts, for example, it can be 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts , 10 copies, etc.

In the present invention, the parts by weight of modified graphene oxide are 1-5 parts, such as 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc. .

In the present invention, the weight part of the catalyst is 0.1-0.5 part, for example, it can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, etc.

Preferably, the polyester polyol comprises polybutylene succinate, polybutylene adipate, polyhexamethylene adipate or polybutylene ethylene adipate. Any one or a combination of at least two.

Preferably, the number average molecular weight of the polyester polyol is 1000-3000, for example, it can be 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 2600, 2800, 3000 and the like.

Preferably, the number average molecular weight of the polyethylene glycol is 400-2000, for example, it can be 400, 600, 8000, 1000, 1200, 1400, 1600, 1800, 2000 and the like.

Preferably, the fluorine-containing polyol comprises any one or at least two of perfluoropolyether alcohol, tridecafluoro-n-octanol, hexafluoro-n-propanol, hexafluoroisopropanol or hexafluoro-n-butanol combination, preferably tridecafluoro-n-octanol and/or hexafluoro-n-butanol.

Preferably, the chain extender includes any one or a combination of at least two of ethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,3-hexanediol.

Preferably, the modified graphene oxide is chitosan modified graphene oxide.

In the present invention, the preparation method of the chitosan-modified graphene oxide is as follows: after the graphene oxide is dispersed in a solvent (such as THF, DMF, etc.), after adding chitosan, after ultrasonic dispersion, react at room temperature for more than 10 hours The chitosan-modified graphene oxide can be obtained. Chitosan-graphene oxide is obtained by modifying graphene oxide with chitosan. Chitosan contains a large number of amino groups and hydroxyl groups, which can produce strong hydrogen bonds with graphene oxide. The existence of hydrogen bonds can make thinner oxidized Graphene sheets are partially stacked on the surface of chitosan to form large-scale folded substances, which can impose strong geometric constraints on the mobility of polymer molecules and mechanically interlock with polymer chains, making the TPU composite material. The degree of bonding is increased, and the deformation resistance of the material during the stretching process is improved.

Preferably, the raw materials for the preparation of the modified porous silica include in parts by weight: 100 parts of silica, 1-5 parts of ammonia water, 1-5 parts of surfactant, 0.5-2 parts of silane coupling agent and 50-60 parts of solvent.

In the raw materials for the preparation of the modified porous silica, the weight fraction of ammonia water is 1-5 parts, for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts servings, 5 servings, etc.

In the preparation raw materials of the modified porous silica, the weight part of the surfactant is 1-5 parts, for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts , 4.5 copies, 5 copies, etc.

In the preparation raw materials of the modified porous silica, the weight part of the silane coupling agent is 0.5-2 parts, for example, it can be 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, 1.2 part servings, 1.4 servings, 1.6 servings, 1.8 servings, 2 servings, etc.

In the raw materials for the preparation of the modified porous silica, the weight of the solvent is 50-60 parts, such as 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts 58, 59, 60, etc.

Preferably, the surfactant is a cationic surfactant, preferably one of dodecyltrimethylammonium bromide, cetyltrimethylammonium bromide or octadecyltrimethylammonium bromide any one or a combination of at least two.

Preferably, the silane coupling agent is an epoxy group-containing silane coupling agent, preferably γ-glycidoxypropyltrimethoxysilane.

Preferably, the solvent is THF and/or DMF.

Preferably, the modified porous silica is prepared by the following preparation method: mixing silica, ammonia water and a solvent, performing a preheating reaction, then adding a cationic surfactant and a silane coupling agent, mixing and stirring, to obtain The modified porous silica.

Preferably, the temperature of the preheating reaction is 120-130°C, such as 120°C, 122°C, 124°C, 126°C, 128°C, 130°C, etc., and the time of the preheating reaction is 1-2h, For example, it can be 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h and so on.

Preferably, the temperature of the mixing and stirring is 140-160°C, such as 140°C, 142°C, 146°C, 148°C, 150°C, 152°C, 154°C, 156°C, 158°C, 160°C, etc. The mixing and stirring time is 40-50min, such as 40min, 42min, 44min, 46min, 48min, 50min, etc.

Preferably, the specific surface area of the modified porous silica is 600-800 m ² /g, such as 600 m ² /g, 620 m ² /g, 640 m ² /g, 660 m ² /g, 680 m ² /g, 700m ² /g, 720m ² /g, 740m ² /g, 760m ² /g, 780m ² /g, 800m ² /g, etc., the average pore diameter of the pores of the modified porous silica is 30-50nm, For example, it can be 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm and the like.

Preferably, the catalyst comprises any one or a combination of at least two of dibutyltin dilaurate, stannous octoate or cobalt octoate.

In the second aspect, the present invention provides a preparation method of the high-transparency TPU film for electronic products as described in the first aspect, the preparation method comprising the following steps:

(1) mixing polyester polyol, polyethylene glycol, fluorine-containing polyol, isophorone diisocyanate and a catalyst, and reacting to obtain a polyurethane prepolymer;

(2) mixing the polyurethane prepolymer obtained in step (1), modified graphene oxide and chain extender, and reacting to obtain a polyurethane elastomer;

(3) mixing and stirring the polyurethane elastomer obtained in step (2) and the modified porous silica, and extrusion molding to obtain the high-transparency TPU film for electronic products.

Preferably, the temperature of the reaction in step (1) is 80-120°C, such as 80°C, 90°C, 100°C, 110°C, 120°C, etc., and the reaction time is 2-4h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, etc.

Preferably, the temperature of the reaction in step (2) is 70-80°C, such as 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, etc., and the reaction time is 2-4h, For example, it can be 2h, 2.5h, 3h, 3.5h, 4h and so on.

Preferably, the temperature of the mixing and stirring in step (3) is 50-60°C, for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, etc., and the mixing and stirring time is 20- 30min, for example, can be 20min, 22min, 24min, 26min, 28min, 30min and the like.

Preferably, the extrusion molding in step (3) is performed with a twin-screw extruder, and the temperature of the mixing section of the twin-screw extruder is 160-170°C, for example, 160°C, 162°C, 164°C, 166°C °C, 168 °C, 170 °C, etc., the temperature of the extrusion section of the twin-screw extruder is 170-180 °C, for example, it can be 170 °C, 172 °C, 174 °C, 176 °C, 178 °C, 180 °C, etc., so The temperature of the die head of the twin-screw extruder is 160-170°C, such as 160°C, 162°C, 164°C, 166°C, 168°C, 170°C, and the like.

Preferably, the preparation method of the highly transparent TPU film for electronic products comprises the following steps:

(1) mixing polyester polyol, polyethylene glycol, fluorine-containing polyol, isophorone diisocyanate and a catalyst, and reacting at 80-120° C. for 2-4 hours to obtain a polyurethane prepolymer;

(2) mixing the polyurethane prepolymer obtained in step (1), the modified graphene oxide and the chain extender, and reacting at 70-80° C. for 2-4 hours to obtain a polyurethane elastomer;

(3) The polyurethane elastomer obtained in step (2) and the modified porous silica are mixed and stirred at 50-60° C. for 20-30 minutes, and extruded by a twin-screw extruder. The mixing section of the twin-screw extruder The temperature is 160-170°C, the temperature of the extrusion section of the twin-screw extruder is 170-180°C, and the temperature of the head of the twin-screw extruder is 160-170°C, and then the single-screw extruder is used for extrusion casting. Film-forming or blow-molding film-forming to obtain the high-transparency TPU film for electronic products.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The TPU film material of the present invention is composed of polyester polyol, polyethylene glycol, fluorine-containing polyol, isophorone diisocyanate, chain extender, modified graphene oxide, modified porous diisocyanate in appropriate proportions. The silicon oxide and the catalyst are prepared, and on the basis of ensuring the excellent transparency of the TPU film material, it also has small roughness and excellent mechanical properties, and is more suitable for the protection of electronic products.

(2) The light transmittance of the TPU film material of the present invention is above 97%, the roughness is below 5nm, the tensile strength is above 60-70MPa, and the elongation at break is 800-1000%.

detailed description

The technical solutions of the present invention are further described below through specific embodiments. It should be understood by those skilled in the art that the embodiments are only for helping the understanding of the present invention, and should not be regarded as a specific limitation of the present invention.

Preparation Example 1

This preparation example provides a modified porous silica I, which is prepared by the following preparation method: 100 g of silica, 3 g of 25 wt % ammonia water and 50 g of THF are mixed, and the mixture is mixed at 120 After preheating the reaction for 2 hours, 2g of cetyltrimethylammonium bromide and 1g of γ-glycidyloxypropyltrimethoxysilane were added, and the mixture was mixed and stirred at 150°C for 45min to obtain a specific surface area of 750m ² /g, modified porous silica I with an average pore size of 45 nm.

Preparation Example 2

This preparation example provides a modified porous silica II. The modified porous silica II is prepared by the following preparation method: 100 g of silica, 2 g of 25 wt % ammonia water and 60 g of THF are mixed at 130 After preheating the reaction for 1 h, 3 g of dodecyl trimethyl ammonium bromide and 1 g of γ-glycidyloxypropyltrimethoxysilane were added, and the mixture was mixed and stirred at 150 ° C for 45 min to obtain a specific surface area of 730 m ² /g, modified porous silica II with an average pore size of 42 nm.

Preparation Example 3

This preparation example provides a modified porous silica III. The modified porous silica III is prepared by the following preparation method: 100 g of silica, 4 g of 25 wt% ammonia water and 60 g of THF are mixed at 120 After preheating the reaction for 1 h, 2 g of octadecyltrimethylammonium bromide and 1 g of γ-glycidyloxypropyltrimethoxysilane were added, and the mixture was mixed and stirred at 150 °C for 45 minutes to obtain a specific surface area of 690 m ² /g, modified porous silica III with an average pore size of 38 nm.

Preparation Example 4

This preparation example provides a modified porous silica IV, and the modified porous silica IV is prepared by the following preparation method: 100 g of silica, 3 g of 25 wt % ammonia water and 50 g of THF are mixed, and the mixture is mixed at 120 After preheating the reaction at ℃ for 2h, add 2g of sodium dodecylbenzenesulfonate and 1g of γ-glycidyloxypropyltrimethoxysilane, mix and stir at 150℃ for 45min, to obtain a specific surface area of 620m ² / g, Modified porous silica IV with an average pore size of 33 nm.

Preparation Example 5

This preparation example provides a modified porous silica V, the modified porous silica V is prepared by the following preparation method: 100 g of silica, 3 g of 25wt% ammonia water and 50 g of THF are mixed, After preheating the reaction for 2 hours at ℃, 1 g of γ-glycidyloxypropyltrimethoxysilane was added, and the mixture was mixed and stirred at 150 ℃ for 45 minutes to obtain a modified porous bilayer with a specific surface area of 580 m ² /g and an average pore diameter of 28 nm. Silicon oxide V.

Preparation Example 6

This preparation example provides a chitosan-modified graphene oxide, and the chitosan-modified graphene oxide is prepared by the following preparation method: disperse 100 g of graphene oxide in 50 mL of THF, add 10 g of chitosan , ultrasonic dispersion was carried out, the ultrasonic power was 600W, and the grafting reaction was carried out by stirring at 200 r/min at 25 °C for 12 h to obtain a chitosan modified graphene oxide dispersion, which was concentrated and dried to obtain a chitosan modified oxidation solution. Graphene.

Example 1

The present embodiment provides a high-transparency TPU film for electronic products, and the preparation raw materials of the high-transparency TPU film for electronic products include the following components in parts by weight:

Wherein, the number-average molecular weight of polybutylene adipate is 2000, the number-average molecular weight of polyethylene glycol is 800, and the modified porous silica is modified porous silica I provided in Preparation Example 1.

The preparation method of the high-transparency TPU film for electronic products described in this embodiment comprises the following steps:

(1) Mix polybutylene adipate, polyethylene glycol, tridecafluoro-n-octanol, isophorone diisocyanate and dibutyltin dilaurate, and react at 100° C. for 3 hours to obtain a polyurethane prepolymer thing;

(2) mixing the polyurethane prepolymer obtained in step (1), chitosan-modified graphene oxide and ethylene glycol, and reacting at 75° C. for 3 hours to obtain a polyurethane elastomer;

(3) The polyurethane elastomer obtained in step (2) and the modified porous silica I were mixed and stirred at 50° C. for 30 min, and extruded by a twin-screw extruder, and the temperature of the mixing section of the twin-screw extruder was 160°C °C, the temperature of the extrusion section of the twin-screw extruder is 180 °C, and the temperature of the head of the twin-screw extruder is 160 °C, and then the single-screw extrusion is used to cast a film to obtain the electronic product. High transparent TPU film.

Example 2

The present embodiment provides a high-transparency TPU film for electronic products, and the preparation raw materials of the high-transparency TPU film for electronic products include the following components in parts by weight:

The number average molecular weight of polybutylene adipate is 1000, the number average molecular weight of polyethylene glycol is 1000, and the modified porous silica is modified porous silica II provided in Preparation Example 2.

The preparation method of the high-transparency TPU film for electronic products described in this embodiment comprises the following steps:

(1) mixing polybutylene adipate, polyethylene glycol, hexafluoro-n-butanol, isophorone diisocyanate and stannous octoate, and reacting at 100° C. for 3 hours to obtain a polyurethane prepolymer;

(2) mixing the polyurethane prepolymer obtained in step (1), chitosan-modified graphene oxide and ethylene glycol, and reacting at 75° C. for 3 hours to obtain a polyurethane elastomer;

(3) The polyurethane elastomer obtained in step (2) and the modified porous silica II were mixed and stirred at 50° C. for 30 minutes, and extruded by a twin-screw extruder, and the temperature of the mixing section of the twin-screw extruder was 170° C. °C, the temperature of the extrusion section of the twin-screw extruder is 180 °C, and the temperature of the head of the twin-screw extruder is 160 °C, and then the single-screw extrusion is used to cast a film to obtain the electronic product. High transparent TPU film.

Example 3

The present embodiment provides a high-transparency TPU film for electronic products, and the preparation raw materials of the high-transparency TPU film for electronic products include the following components in parts by weight:

The number average molecular weight of polybutylene adipate is 2000, the number average molecular weight of polyethylene glycol is 600, and the modified porous silica is modified porous silica III provided in Preparation Example 3.

The preparation method of the high-transparency TPU film for electronic products described in this embodiment comprises the following steps:

(1) mixing polybutylene adipate, polyethylene glycol, hexafluoro-n-butanol, isophorone diisocyanate and stannous octoate, and reacting at 100° C. for 3 hours to obtain a polyurethane prepolymer;

(2) mixing the polyurethane prepolymer obtained in step (1), chitosan-modified graphene oxide and ethylene glycol, and reacting at 75° C. for 3 hours to obtain a polyurethane elastomer;

(3) The polyurethane elastomer obtained in step (2) and the modified porous silica III were mixed and stirred at 50° C. for 30 minutes, and extruded by a twin-screw extruder. The temperature of the mixing section of the twin-screw extruder was 170 °C, the temperature of the extrusion section of the twin-screw extruder is 180 °C, and the temperature of the head of the twin-screw extruder is 160 °C, and then the single-screw extrusion is used to cast a film to obtain the electronic product. High transparent TPU film.

Example 4

This embodiment provides a high-transparency TPU film for electronic products. The only difference from Embodiment 1 is that the modified porous silica I is replaced with an equivalent mass of six-modified porous silica IV, and the contents of other components and The preparation method is the same as in Example 1.

Example 5

This embodiment provides a high-transparency TPU film for electronic products. The only difference from Embodiment 1 is that the modified porous silica I is replaced with the same quality of modified porous silica V, and the contents of other components and the preparation The method is the same as in Example 1.

Example 6

This embodiment provides a high-transparency TPU film for electronic products. The only difference from Embodiment 1 is that tridecafluoro-n-octanol is replaced with hexafluoroisopropanol of the same quality, and the contents and preparation methods of other components are the same as in the implementation. example 1.

Example 7

This embodiment provides a high-transparency TPU film for electronic products. The only difference from Embodiment 1 is that the content of polyethylene glycol is 1 part, the content of tridecafluoro-n-octanol is 11 parts, and the content of other components and The preparation method is the same as in Example 1.

Example 8

This embodiment provides a high-transparency TPU film for electronic products. The only difference from Embodiment 1 is that the content of polyethylene glycol is 11 parts, the content of tridecafluoro-n-octanol is 1 part, and the content of other components and The preparation method is the same as in Example 1.

Comparative Example 1

This comparative example provides a high-transparency TPU film for electronic products. The only difference from Example 1 is that polyethylene glycol is not added, the content of polybutylene adipate is increased to 58 parts, and the content and preparation of other components The method is the same as in Example 1.

Comparative Example 2

This comparative example provides a high-transparency TPU film for electronic products. The difference from Example 1 is that no tridecafluoro-n-octanol is added, the content of polybutylene adipate is increased to 54 parts, and the content of other components is And the preparation method is the same as Example 1.

Comparative Example 3

This comparative example provides a high-transparency TPU film for electronic products. The difference from Example 1 is that isophorone diisocyanate is replaced with hexamethylene diisocyanate of the same quality, and the contents and preparation methods of other components are the same Example 1.

Comparative Example 4

This comparative example provides a highly transparent TPU film for electronic products. The only difference from Example 1 is that chitosan-modified graphene oxide is not added, the content of modified porous silica is increased to 5 parts, and other components The content and preparation method are the same as those in Example 1.

Comparative Example 5

This comparative example provides a highly transparent TPU film for electronic products. The only difference from Example 1 is that no modified porous silica is added, the content of chitosan-modified graphene oxide is increased to 5 parts, and other components are The content and preparation method are the same as those in Example 1.

Comparative Example 6

This comparative example provides a high-transparency TPU film for electronic products, and the difference from Example 1 is only that the modified graphene oxide is replaced with graphene oxide of equal quality, and the content of other components and the preparation method are the same as those of Example 1.

Comparative Example 7

This comparative example provides a high-transparency TPU film for electronic products. The only difference from Example 1 is that the modified porous silica is replaced with silica of equal quality, and the contents and preparation methods of other components are the same as those of Example 1. .

Performance Testing

Various performance tests were carried out on the high-transparency TPU films for electronic products prepared in the above examples 1-8 and the high-transparency TPU films for electronic products prepared in the comparative examples 1-7. Among them, the light transmittance is tested by the light transmittance test standard GB/T 2410-2008, the roughness is tested by the atomic force microscope of Bruker Company in Germany, and the tensile strength of each film material is tested according to GB/T1040.3-2006, according to GB/T 1040.1-2006 tests the elongation at break of each film material.

The specific test results are shown in Table 1 below:

Table 1

project	Transmittance/%	Roughness/nm	Tensile strength/MPa	Elongation at break%
Example 1	99.5	3.9	68	960
Example 2	99.2	3.9	70	980
Example 3	99.5	4.0	69	950
Example 4	99.0	4.5	66	920
Example 5	97.5	4.5	67	890
Example 6	98.2	4.2	65	850
Example 7	98.0	4.6	62	860
Example 8	97.8	4.5	63	840
Comparative Example 1	91.5	6.8	52	620
Comparative Example 2	92.3	7.2	51	730
Comparative Example 3	90.5	6.5	48	640
Comparative Example 4	95.2	12.0	46	650
Comparative Example 5	89.9	8.2	42	610
Comparative Example 6	91.6	15.4	52	700

Comparative Example 7

86.7

16.8

56

720

It can be seen from the test data in Table 1 that the light transmittance of the TPU film material of the present invention is above 97%, the roughness is below 5nm, the tensile strength is above 60-70MPa, and the elongation at break is 800-1000%. Explain that the TPU film material of the present invention is composed of appropriate proportions of polyester polyol, polyethylene glycol, fluorine-containing polyol, isophorone diisocyanate, chain extender, modified graphene oxide, modified porous silica And the catalyst is prepared, on the basis of ensuring the excellent transparency of the TPU film material, it also has small roughness and excellent mechanical properties, and is more suitable for the protection of electronic products.

From the comparison between Example 1 and Examples 4 and 5, it can be seen that the cationic surfactant helps to form modified porous silica with high surface area and high pore size, so as to more reliably adsorb metal ions to further improve the light transmittance of the film , and reduce its roughness. From the comparison of Example 1 and Examples 7 and 8, it can be seen that when the ratio of polyethylene glycol and tridecafluoro-n-octanol is within the scope of the application, the prepared TPU film material has more excellent transparency and flexibility and is more flexible. small roughness.

It can be seen from the comparison between Example 1 and Comparative Example 1 that, lack of polyethylene glycol, the content of the rigid segment cannot be well increased, so the tensile strength and elongation of the film decrease significantly. From Example 1 and Comparative Example 2, lack of fluorine-containing polyol, the optical transparency and flexibility of the film decreased significantly. It can be seen from the comparison between Example 1 and Comparative Example 3 that the film formed by isophorone diisocyanate is more transparent, because the isophorone diisocyanate molecule is asymmetric and difficult to form crystals. From the comparison of Example 1 and Comparative Examples 4-7, it can be seen that when the modified graphene oxide and modified porous silica are not added, or the two are replaced with unmodified graphene oxide and The optical transparency and flexibility decreased significantly, and the roughness increased significantly.

The applicant declares that the present invention describes the high-transparency TPU film for electronic products and its preparation method by the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is to say, it does not mean that the present invention can only be implemented by relying on the above-mentioned embodiments. . Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims (10)

1. A high-transparency TPU film for electronic products, characterized in that, the preparation raw materials of the high-transparency TPU film for electronic products include the following components in parts by weight:

   
2. The highly transparent TPU film for electronic products according to claim 1, wherein the polyester polyol comprises polybutylene succinate, polybutylene adipate, polyhexamethylene adipate Any one or a combination of at least two alcohol esters or polybutylene adipate glycol esters;

   Preferably, the number average molecular weight of the polyester polyol is 1000-3000.
3. The high-transparency TPU film for electronic products according to claim 1 or 2, wherein the number-average molecular weight of the polyethylene glycol is 400-2000;

   Preferably, the fluorine-containing polyol comprises any one or at least two of perfluoropolyether alcohol, tridecafluoro-n-octanol, hexafluoro-n-propanol, hexafluoroisopropanol or hexafluoro-n-butanol combination, preferably tridecafluoro-n-octanol and/or hexafluoro-n-butanol;

   Preferably, the chain extender includes any one or a combination of at least two of ethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,3-hexanediol.
4. The highly transparent TPU film for electronic products according to any one of claims 1-3, wherein the modified graphene oxide is chitosan modified graphene oxide.
5. The high-transparency TPU film for electronic products according to any one of claims 1-4, wherein the raw materials for preparing the modified porous silica include in parts by weight: 100 parts of silica, ammonia water 1-5 parts, 1-5 parts of surfactant, 0.5-2 parts of silane coupling agent and 50-60 parts of solvent;

   Preferably, the surfactant is a cationic surfactant, preferably one of dodecyltrimethylammonium bromide, cetyltrimethylammonium bromide or octadecyltrimethylammonium bromide any one or a combination of at least two;

   Preferably, the silane coupling agent is an epoxy group-containing silane coupling agent, preferably γ-glycidoxypropyltrimethoxysilane;

   Preferably, the solvent is THF and/or DMF;

   Preferably, the modified porous silica is prepared by the following preparation method: mixing silica, ammonia water and a solvent, performing a preheating reaction, then adding a cationic surfactant and a silane coupling agent, mixing and stirring, to obtain the modified porous silica;

   Preferably, the temperature of the preheating reaction is 120-130°C, and the time of the preheating reaction is 1-2h;

   Preferably, the temperature of the mixing and stirring is 140-160° C., and the time of the mixing and stirring is 40-50 min;

   Preferably, the specific surface area of the modified porous silica is 600-800 m ² /g, and the average pore diameter of the pores of the modified porous silica is 30-50 nm.
6. The highly transparent TPU film for electronic products according to any one of claims 1-5, wherein the catalyst comprises any one or at least two of dibutyltin dilaurate, stannous octoate or cobalt octoate The combination.
7. According to the preparation method of the high-transparency TPU film for electronic products according to any one of claims 1-6, the preparation method comprises the following steps:

   (1) polyester polyol, polyethylene glycol, fluorine-containing polyol, isophorone diisocyanate and catalyzer are mixed, and reaction obtains polyurethane prepolymer;

   (2) mixing the polyurethane prepolymer obtained in step (1), modified graphene oxide and chain extender, and reacting to obtain a polyurethane elastomer;

   (3) mixing and stirring the polyurethane elastomer obtained in step (2) and the modified porous silica, and extrusion molding to obtain the high-transparency TPU film for electronic products.
8. The preparation method according to claim 7, wherein the temperature of the reaction in step (1) is 80-120°C, and the time of the reaction is 2-4h;

   Preferably, the temperature of the reaction in step (2) is 70-80° C., and the reaction time is 2-4 h.
9. The preparation method according to claim 7 or 8, wherein the temperature of the mixing and stirring in step (3) is 50-60° C., and the time of the mixing and stirring is 20-30 min;

   Preferably, the extrusion molding in step (3) is carried out with a twin-screw extruder, the temperature of the mixing section of the twin-screw extruder is 160-170° C., and the temperature of the extrusion section of the twin-screw extruder is 170-180°C, and the temperature of the die head of the twin-screw extruder is 160-170°C.
10. The preparation method according to any one of claims 7-9, wherein the preparation method of the high-transparency TPU film for electronic products comprises the following steps:

    (1) mixing polyester polyol, polyethylene glycol, fluorine-containing polyol, isophorone diisocyanate and a catalyst, and reacting at 80-120° C. for 2-4 hours to obtain a polyurethane prepolymer;

    (2) mixing the polyurethane prepolymer obtained in step (1), modified graphene oxide and chain extender, and reacting at 70-80° C. for 2-4 hours to obtain a polyurethane elastomer;

    (3) The polyurethane elastomer obtained in step (2) and the modified porous silica are mixed and stirred at 50-60° C. for 20-30 minutes, and extruded by a twin-screw extruder. The mixing section of the twin-screw extruder The temperature is 160-170°C, the temperature of the extrusion section of the twin-screw extruder is 170-180°C, the temperature of the head of the twin-screw extruder is 160-170°C, and then the single-screw extruder is used for extrusion casting. Film-forming or blow-molding film-forming to obtain the high-transparency TPU film for electronic products.