Anti-ultraviolet matte polyester film and preparation method thereof

Abstract

The invention discloses an anti-ultraviolet matte polyester film which comprises a base film as a middle layer; the matte surface layer is at least arranged on one surface of the base film; the matt surface layer comprises first matt particles and second matt particles, the first matt particles are silicon dioxide modified and grafted with an organic anti-ultraviolet agent through a silane coupling agent, the second matt particles are silicon dioxide modified and grafted with the organic anti-ultraviolet agent through isocyanato-terminated polyurethane, and the organic anti-ultraviolet agent has hydroxyl. The anti-ultraviolet matt polyester film is reasonable in structure, the first matt particles and the second matt particles are compounded, the matt effect of the polyester film is improved and the mechanical property is ensured under the condition of a small amount, and through combination modification of the isocyanato-terminated polyurethane and the silane coupling agent, not only is the dispersity of the particles improved, but also the anti-ultraviolet matt polyester film is prepared. By grafting the organic anti-ultraviolet agent, the anti-ultraviolet performance and the anti-ultraviolet stability are improved, and the mechanical performance of the matte polyester film is optimized.

Description

Technical Field

[0001] The invention relates to the technical field of film production, in particular to an anti-ultraviolet matte polyester film and a preparation method thereof. Background Art

[0002] With the change of consumption concepts, people begin to be interested in low-gloss matte films. The special hazy appearance brought by matte films is more attractive to consumers.

[0003] Polyester film has anti-ultraviolet effect. The commonly used methods are surface coating technology and blending modification. However, the addition of organic ultraviolet absorbers has disadvantages such as migration and irritation to human skin. The addition of inorganic ultraviolet absorbers has the problem of poor dispersion. Inorganic ultraviolet absorbers such as TiO2 and ZnO are expensive. Reducing the amount added will not achieve the anti-ultraviolet effect and shorten the duration of anti-ultraviolet.

[0004] Therefore, it is necessary to improve the anti-ultraviolet matte polyester film in the prior art. Summary of the invention

[0005] One of the purposes of the present invention is to overcome the defects existing in the prior art and provide an anti-ultraviolet matte polyester film. The first matte particles and the second matte particles are compounded to improve the matte effect of the polyester film in a small amount and ensure the mechanical properties. The modification by combining isocyanate-terminated polyurethane and silane coupling agent not only improves the dispersibility of the particles, but also improves the anti-ultraviolet performance and anti-ultraviolet stability by grafting organic anti-ultraviolet agents, and optimizes the mechanical properties of the matte polyester film.

[0006] In order to achieve the above technical effects, the technical solution of the present invention is: an anti-ultraviolet matte polyester film, which is a co-extruded film, comprising:

[0007] Basement membrane, which is the middle layer;

[0008] A matte surface layer is provided on at least one surface of the base film;

[0009] The matte surface layer includes first matte particles and second matte particles, the first matte particles are silica modified by a silane coupling agent and grafted with an organic anti-ultraviolet agent, the second matte particles are silica modified by an isocyanate-terminated polyurethane and grafted with an organic anti-ultraviolet agent, and the organic anti-ultraviolet agent has a hydroxyl group.

[0010] The preferred technical solution is that the organic anti-ultraviolet agent is benzophenone and benzotriazole, the benzophenone is one or more of 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2,2',4-trihydroxybenzophenone, and 4-hydroxybenzophenone; the benzotriazole is one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole.

[0011] A preferred technical solution is that the silane coupling agent is 3-chloropropyltrimethoxysilane.

[0012] The preferred technical solution is that the isocyanate-terminated polyurethane is prepared by catalytic polymerization of isophorone diisocyanate and polyether diol, and the molecular weight of the polyether diol is 1000-1600; further, the molar ratio of isophorone diisocyanate to polyether diol is (2-2.3)-1.

[0013] A preferred technical solution is that the particle size of one of the first matte particles and the second matte particles is 300-500 nm, and the particle size of the other is 1-2 μm.

[0014] A preferred technical solution is that the mass ratio of the first matte particles to the second matte particles is 1:(1-3).

[0015] A preferred technical solution is that the total mass of the first matte particles and the second matte particles is 2% to 8% of the total mass of the matte surface layer.

[0016] A preferred technical solution is that the thickness of one of the matte surface layers accounts for 5.5% to 8.5% of the total thickness of the co-extruded film, and the total film thickness of the co-extruded film is 35 to 135 μm.

[0017] The preferred technical scheme is that the preparation method of matte particles is as follows: a hydroxy organic anti-ultraviolet agent and a strong base powder are dissolved in an N,N-dimethylformamide solvent, reacted at 50-60°C to obtain a phenolate, a silane coupling agent is added dropwise to the phenolate after removing the system water, reacted at 50-60°C, then the organic anti-ultraviolet agent-modified silane coupling agent is removed and washed to obtain the silane coupling agent, dissolved in a first solvent of acetone and deionized water, hydrolyzed at 40-50°C, silicon dioxide is added, and finally dried;

[0018] Preparation method 2 of matte particles: Silica is dissolved in acetone, isocyanate-terminated polyurethane and organic metal tin catalyst are added, reacted at 40-50°C to obtain polyurethane-modified silica, washed and filtered, and then redispersed in acetone, and then hydroxy organic anti-ultraviolet agent and organic metal tin catalyst are added, washed again after reaction and finally dried.

[0019] The second object of the present invention is to overcome the defects existing in the prior art and provide a method for preparing an anti-ultraviolet matte polyester film, comprising the following steps:

[0020] S1: configuring first matte particles and second matte particles;

[0021] S2: The matte surface layer, the base film and the matte surface layer are sequentially stacked and co-extruded into a cast sheet, and then biaxially stretched, heat-set, cooled, drawn, corona-treated and rolled to obtain a matte polyester film;

[0022] The matte surface layer is made by mixing and co-extruding the first matte particles and the second matte particles with polyester;

[0023] The temperature for longitudinal stretching is 70-100°C, the stretching ratio is 3-3.6 times, and the stretching rate is 80-120m / min; the temperature for transverse stretching is 110-125°C, the stretching ratio is 3-3.8 times, and the stretching rate is 80-120m / min; the heat setting temperature is 220-240°C.

[0024] The advantages and beneficial effects of the present invention are:

[0025] The anti-ultraviolet matte polyester film has a reasonable structure. The first matte particles and the second matte particles are compounded to improve the matte effect of the polyester film and ensure the mechanical properties. The isocyanate-terminated polyurethane and the silane coupling agent are combined and modified to improve the dispersibility of the particles, the grafted organic anti-ultraviolet agent improves the anti-ultraviolet performance and anti-ultraviolet stability, and optimizes the mechanical properties of the matte polyester film. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described below in conjunction with the examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0027] Isocyanate-terminated polyurethane

[0028] The invention is prepared by catalytic polymerization of isophorone diisocyanate and polyether diol, wherein the molecular weight of the polyether diol is 1000-1600; further, the molar ratio of isophorone diisocyanate to polyether diol is (2-2.3)-1.

[0029] Among them, isophorone diisocyanate (IPDI) has two different types of -NCO groups, and the group activities are different, so the reaction conditions can be controlled. The polyether diol selectively reacts with the -NCO on the aliphatic primary position to form a -NCO-terminated polyurethane, which is also a polyether-based polyurethane. The selection of polyether diol forms a linear polyurethane, reduces steric hindrance, and is more grafted on the surface of silica. The resulting polyether-based polyurethane has better hydrolysis stability than polyester-based polyurethane. In a humid environment or when in contact with water, the performance of polyether-based polyurethane is more stable and not easy to degrade; polyether-based polyurethane usually has a lower glass transition temperature (Tg), so it can still maintain good flexibility and elasticity at low temperatures. Polyether-based polyurethane can provide good tensile strength, tear strength and wear resistance.

[0030] Preparation of first matte particles and second matte particles

[0031] Preparation method 1: 10g of hydroxy organic anti-ultraviolet agent and 3g of NaOH powder are dissolved in 100ml of N,N-dimethylformamide solvent, reacted at 55°C to obtain phenol salt, 10g of 3-chloropropyltrimethoxysilane is added dropwise to the phenol salt after removing the system water, and reacted at 60°C, then the organic anti-ultraviolet agent-modified silane coupling agent is removed and washed to obtain a silane coupling agent, 5g of the organic anti-ultraviolet agent-modified silane coupling agent is taken, dissolved in 50ml of the first solvent mixed with acetone and deionized water in a mass ratio of 10:1, hydrolyzed at 48°C, 5g of silica is added, and finally dried in a vacuum oven at 100°C.

[0032] Preparation method 2: Take 5g of silica and dissolve it in 60ml of acetone, add 20g of isocyanate-terminated polyurethane and 150mg of organic metal tin catalyst, react at 45°C to obtain polyurethane-modified silica, wash and filter it, and then redisperse it in 40ml of acetone, then add 5g of hydroxyl organic anti-ultraviolet agent and 150mg of organic metal tin catalyst, react at 45°C, then wash and finally dry it.

[0033] Organic UV inhibitor

[0034] Benzophenones have strong ultraviolet absorption capabilities, especially in the UVB region (290-320nm).

[0035] Benzotriazoles protect the UVA region (320-400nm) and part of the UVB region (290-320nm), and have good color stability and are not prone to yellowing. They have good compatibility with a variety of polymers and have high thermal stability. Compounding with benzophenone organic anti-ultraviolet agents can optimize anti-ultraviolet performance and reduce costs.

[0036] The embodiment uses 4-hydroxybenzophenone, which is a highly efficient UV absorber and can provide good light stability. Compared with other types of UV absorbers, the cost of 4-hydroxybenzophenone is relatively low. The 2-(2'-hydroxy-5'-methylphenyl)benzotriazole used is a widely used highly efficient UV absorber and has a good absorption effect on UVA and part of UVB regions.

[0037] Example 1

[0038] The anti-ultraviolet matte polyester film is a co-extruded film, comprising a base film and a matte surface layer, wherein the base film is an intermediate layer, and the matte surface layer is disposed on both surfaces of the base film; the matte surface layer comprises a first matte particle and a second matte particle, wherein the first matte particle is obtained by preparation method one, and the hydroxy organic anti-ultraviolet agent is 4-hydroxybenzophenone; the second matte particle is obtained by preparation method two, and the hydroxy organic anti-ultraviolet agent is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole. The particle size of the first matte particle is 350nm, the particle size of the second matte particle is 1.5μm, and the mass ratio of the first matte particle to the second matte particle is 1:2. The matte surface layer also includes FG600 polyester, and the total mass ratio of the first matte particle and the second matte particle to the mass ratio of the polyester is 6:94.

[0039] The preparation method of the anti-ultraviolet matte polyester film comprises the following steps:

[0040] S1: preparing first matte particles and second matte particles;

[0041] S2: The matte surface layer, base film and matte surface layer are stacked in sequence to form a co-extruded cast sheet. The base film is 100% FG600 polyester. After biaxial stretching, heat setting, cooling, pulling, corona treatment and winding, the matte polyester film is obtained. Among them, the longitudinal stretching temperature is 80°C, the stretching ratio is 3.5 times, and the stretching rate is 100m / min; the transverse stretching temperature is 120°C, the stretching ratio is 3.6 times, and the stretching rate is 105m / min; the heat setting temperature is 225°C.

[0042] The total film thickness of the matte polyester film was 100 μm, and the layer thickness of the matte surface layer was 7 μm.

[0043] Example 2

[0044] Example 2 is based on Example 1, except that the first matte particles are obtained by preparation method 1, and the hydroxy organic anti-ultraviolet agent is 4-hydroxybenzophenone; the second matte particles are obtained by preparation method 2, and the hydroxy organic anti-ultraviolet agent is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole. The particle size of the first matte particles is 1.5 μm, the particle size of the second matte particles is 350 nm, and the mass ratio of the first matte particles to the second matte particles is 1:2.

[0045] Example 3

[0046] Example 3 is based on Example 2, except that the mass ratio of the first matte particles to the second matte particles is 1:1, and the other parameters remain unchanged.

[0047] Example 4

[0048] Example 4 is based on Example 2, except that the mass ratio of the first matte particles to the second matte particles is 1:3, and the other parameters remain unchanged.

[0049] Example 5

[0050] Example 5 is based on Example 2, except that the mass ratio of the total mass of the first matte particles and the second matte particles to the mass of the polyester is 2:98, and the other parts remain unchanged.

[0051] Example 6

[0052] Example 6 is based on Example 2, except that the mass ratio of the total mass of the first matte particles and the second matte particles to the mass of the polyester is 12:90, and the other parts remain unchanged.

[0053] Example 7

[0054] Example 7 is based on Example 2, except that the particle sizes of the first matte particles and the second matte particles are both 1.5 μm, and the other parameters remain unchanged.

[0055] Example 8

[0056] Example 8 is based on Example 2, except that the particle sizes of the first matte particles and the second matte particles are both 350 nm, and the other parameters remain unchanged.

[0057] Comparative Example 1

[0058] Comparative Example 1 is based on Example 2, except that the first matte particles are only modified with a silane coupling agent, and the rest remain unchanged.

[0059] Comparative Example 2

[0060] Comparative Example 2 is based on Example 2, except that the second matte particles are only modified with a silane coupling agent, and the rest remain unchanged.

[0061] Comparative Example 3

[0062] Comparative Example 3 is based on Example 2, except that the first matte particles and the second matte particles are not modified, and the other properties remain unchanged.

[0063] Comparative Example 4

[0064] Comparative Example 4 is based on Example 2, except that the matte surface layer contains only the first matte particles, and the others remain unchanged.

[0065] Comparative Example 5

[0066] Comparative Example 5 is based on Example 2, except that the matte surface layer only contains the second matte particles, and the other parts remain unchanged.

[0067] Comparative Example 6

[0068] Comparative Example 6 is based on Example 1, except that the second matte particles are directly modified and grafted with an organic anti-ultraviolet agent by isophorone diisocyanate, and are not polymerized with polyether diol.

[0069] Performance Test:

[0070] 1. Haze and transmittance test: AT-4725 transmission haze meter from BYK of Germany is used;

[0071] 2. Tensile strength and elongation at break test: according to standard ASTM D882;

[0072] 3. UV stability test: According to the standard IEC61215-2005, measure the UV radiation, the UV radiation with a wavelength of 280nm to 385nm is 50kWh·m -2 The elongation at break retention rate of matte polyester film after UV irradiation. The elongation at break retention rate refers to the ratio of the elongation at break after UV irradiation to the elongation at break of the sample without irradiation multiplied by 100%.

[0073] The test results of the embodiments and comparative examples are shown in the following table:

[0074]

[0075]

[0076] To achieve a matte effect, the haze should be ≥ 55%.

[0077] Compared with Example 2, in Example 1, when other conditions remain unchanged, the content of 1.5 μm particles is greater than the content of 350 nm particles, and the matte effect is better, but the mechanical properties are reduced.

[0078] Compared with Example 2, in Example 3, while the total mass of the first matte particles and the second matte particles remains unchanged, the content ratio of 1.5 μm particles increases, which improves the matte effect. At the same time, the content of polyurethane modified by the second matte particles (350 nm) decreases, resulting in a decrease in mechanical properties.

[0079] Compared with Example 2, in Example 4, while the total mass of the first matte particles and the second matte particles remains unchanged, the content ratio of the 350nm particles increases, and the matte effect decreases. As the content of the modified polyurethane of the second matte particles (350nm) increases, the mechanical properties are improved, and the benzotriazole anti-ultraviolet agent is increased, the anti-ultraviolet performance is also improved.

[0080] Compared with Example 2, in Example 5, the total mass of the first matte particles and the second matte particles is reduced, and the matte effect and the anti-ultraviolet effect are both reduced.

[0081] Compared with Example 2, in Comparative Example 1, the first matte particles were not modified with an organic anti-ultraviolet agent, and the anti-ultraviolet performance was reduced.

[0082] Compared with Example 2, the second matte particles in Comparative Example 2 were not modified by the isocyanate-terminated polyurethane-modified grafted organic anti-ultraviolet agent, and both the mechanical properties and anti-ultraviolet properties were reduced.

[0083] Compared with Example 2, in Comparative Example 3, the first matte particles and the second matte particles are unevenly dispersed, which increases the difficulty of processing.

[0084] Compared with Example 2, in Comparative Example 6, the second matte particles are directly modified and grafted with an organic anti-ultraviolet agent by isophorone diisocyanate, which has a negative effect on the mechanical properties of the film.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An anti-ultraviolet matte polyester film, which is a co-extruded film, comprising: Basement membrane, which is the middle layer; A matte surface layer is provided on at least one surface of the base film; It is characterized in that the matte surface layer includes first matte particles and second matte particles, the first matte particles are silica modified by a silane coupling agent and grafted with an organic anti-ultraviolet agent, the second matte particles are silica modified by an isocyanate-terminated polyurethane and grafted with an organic anti-ultraviolet agent, and the organic anti-ultraviolet agent has a hydroxyl group.

2. The UV-resistant matte polyester film according to claim 1, characterized in that: The organic anti-ultraviolet agent is benzophenone and benzotriazole, the benzophenone is one or more of 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2,2',4-trihydroxybenzophenone, and 4-hydroxybenzophenone; the benzotriazole is one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole.

3. The UV-resistant matte polyester film according to claim 1 or 2, characterized in that: The silane coupling agent is 3-chloropropyltrimethoxysilane.

4. The UV-resistant matte polyester film according to claim 1 or 2, characterized in that: The isocyanate-terminated polyurethane is prepared by catalytic polymerization of isophorone diisocyanate and polyether diol, and the molecular weight of the polyether diol is 1000-1600; further, the molar ratio of isophorone diisocyanate to polyether diol is (2-2.3)-1.

5. The UV-resistant matte polyester film according to claim 1, characterized in that: One of the first matte particles and the second matte particles has a particle size of 300-500 nm, and the other has a particle size of 1-2 μm.

6. The UV-resistant matte polyester film according to claim 1 or 5, characterized in that: The mass ratio of the first matte particles to the second matte particles is 1:(1-3).

7. The UV-resistant matte polyester film according to claim 6, characterized in that: The total mass of the first matte particles and the second matte particles is 2% to 8% of the total mass of the matte surface layer.

8. The UV-resistant matte polyester film according to claim 1, characterized in that: The thickness of one of the matte surface layers accounts for 5.5% to 8.5% of the total thickness of the co-extruded film, and the total thickness of the co-extruded film is 35 to 135 μm.

9. The UV-resistant matte polyester film according to claim 3, characterized in that: Preparation method 1 of matte particles: a hydroxy organic anti-ultraviolet agent and a strong base powder are dissolved in an N,N-dimethylformamide solvent, reacted at 50-60°C to obtain a phenol salt, a silane coupling agent is added dropwise to the phenol salt after removing the system water, reacted at 50-60°C, and then the organic anti-ultraviolet agent-modified silane coupling agent is removed and washed to obtain the silane coupling agent, dissolved in a first solvent of acetone and deionized water, hydrolyzed at 40-50°C, and then silicon dioxide is added, and finally dried; Preparation method 2 of matte particles: Silica is dissolved in acetone, isocyanate-terminated polyurethane and organic metal tin catalyst are added, and the reaction is carried out at 40-50°C to obtain polyurethane-modified silica, which is then washed and filtered and redispersed in acetone, and then a hydroxy organic anti-ultraviolet agent and an organic metal tin catalyst are added, and the reaction is followed by washing and finally drying.

10. A method for preparing an anti-ultraviolet matte polyester film, characterized in that: The following steps are involved: S1: configuring first matte particles and second matte particles; S2: The matte surface layer, the base film and the matte surface layer are sequentially stacked and co-extruded into a cast sheet, and then biaxially stretched, heat-set, cooled, drawn, corona-treated and rolled to obtain a matte polyester film; The matte surface layer is made by mixing and co-extruding the first matte particles and the second matte particles with polyester; The temperature for longitudinal stretching is 70~100℃, the stretching ratio is 3~3.6 times, and the stretching rate is 80~120m / min; the temperature for transverse stretching is 110~125℃, the stretching ratio is 3~3.8 times, and the stretching rate is 80~120m / min; the heat setting temperature is 220~240℃.

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