A kind of anti-ultraviolet polypropylene synthetic paper and preparation method thereof

Abstract

The invention discloses an anti-ultraviolet polypropylene synthetic paper and a preparation method thereof, and belongs to the technical field of synthetic paper. The polypropylene synthetic paper is composed of an outer layer, an intermediate layer and an inner layer, wherein the outer layer is composed of the following raw materials in parts by weight: 40-50 parts of polypropylene, 20-30 parts of polypropylene carbonate, 2-4 parts of a modified anti-ultraviolet agent, and 1-2 parts of calcium carbonate; the intermediate layer is composed of 20-30 parts of polypropylene, 30-40 parts of polypropylene carbonate, 2-4 parts of a modified anti-ultraviolet agent, and 1-2 parts of calcium carbonate; the raw materials and the number of parts of the inner layer are the same as those of the outer layer. The invention prepares a modified anti-ultraviolet agent by (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide and 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate. The polypropylene synthetic paper prepared by the invention has excellent mechanical properties, anti-ultraviolet and anti-aging properties, and flame retardant properties.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic paper, and in particular to an anti-ultraviolet polypropylene synthetic paper and a preparation method thereof. Background Art

[0002] Polypropylene synthetic paper has many advantages, such as low carbon and environmental protection, low specific gravity, high strength, good weather resistance, good tear resistance, soft texture, excellent printing performance and durability. Polypropylene synthetic paper has been widely used in high-quality printing, high-end packaging and special uses because it has the characteristics of both plastic and paper. With the increase in the application scenarios of polypropylene synthetic paper, such as easy breakage after long-term outdoor exposure, yellowing and fading, more requirements are put forward for polypropylene synthetic paper, such as anti-ultraviolet aging performance when used outdoors.

[0003] A Chinese invention patent with publication number CN104943308A discloses a polypropylene synthetic paper and a production method thereof. The polypropylene synthetic paper includes an outer layer, an intermediate layer and an inner layer. The outer layer is mainly prepared from titanium dioxide, calcium carbonate and a modified polypropylene copolymer, the intermediate layer is mainly prepared from polypropylene, and the inner layer is mainly prepared from titanium dioxide, calcium carbonate and a modified polypropylene copolymer. The paper has excellent mechanical properties, but poor UV resistance, anti-aging and flame retardancy. Summary of the invention

[0004] In view of the shortcomings of the prior art, an object of the present invention is to provide an anti-ultraviolet polypropylene synthetic paper and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] An anti-ultraviolet polypropylene synthetic paper, consisting of an outer layer, an intermediate layer and an inner layer, wherein the outer layer is composed of the following raw materials in parts by weight: 40-50 parts of polypropylene, 20-30 parts of polypropylene carbonate, 2-4 parts of modified anti-ultraviolet agent, and 1-2 parts of calcium carbonate;

[0007] The middle layer is composed of the following raw materials in parts by weight: 20-30 parts of polypropylene, 30-40 parts of polypropylene carbonate, 2-4 parts of modified anti-ultraviolet agent, and 1-2 parts of calcium carbonate;

[0008] The raw materials and the number of portions of the inner surface layer are the same as those of the outer surface layer;

[0009] The modified UV-resistant agent is prepared by the following method:

[0010] DMF was added to the reaction bottle, and the temperature was raised to 75-95°C with stirring, and 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate, (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, and dibenzoyl peroxide were added in sequence. The reaction was carried out under nitrogen protection for 8-10 hours to obtain a reddish brown solution, which was rotary evaporated and vacuum dried at 50-60°C to obtain a modified UV inhibitor. The reaction equation is shown as follows:

[0011] ;

[0012] The mass ratio of DMF, dibenzoyl peroxide, (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, and 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate is (20-30):(0.4-0.8):(2-3):5.

[0013] A method for preparing UV-resistant polypropylene synthetic paper comprises the following steps:

[0014] S1: Extruding the outer layer raw material, the middle layer raw material and the inner layer raw material through an extruder respectively;

[0015] S2: extruding each layer of raw materials extruded by the extruder through a T-type die, and then longitudinally stretching and transversely stretching, followed by cooling, corona treatment, and trimming;

[0016] Among them, the extrusion temperature of the outer layer raw material and the inner layer raw material is 230°C, and the extrusion temperature of the middle layer raw material is 250°C; the preheating section temperature of longitudinal stretching is 130°C, the stretching section temperature is 142°C, the shaping section temperature is 145°C, the longitudinal stretching ratio is 4.9, the preheating section temperature of transverse stretching is 167°C, the stretching section temperature is 155°C, the shaping section temperature is 171°C, the transverse stretching ratio is 9 times, and the corona is 34.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention include:

[0018] The invention adopts (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide and 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate to prepare a modified UV-resistant agent for polypropylene synthetic paper under the action of dibenzoyl peroxide as an initiator.

[0019] The 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate used in the modified anti-ultraviolet agent prepared by the present invention has a hydroxyl group, so it can be chemically bonded to a polymer in the manufacturing process of synthetic paper, so that it has an inherent "permanent" ultraviolet absorption group. However, due to its small molecular weight, it is not resistant to migration. By reacting with (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, the molecular weight of the anti-ultraviolet agent is increased, so that it has both excellent light stabilization effect and the advantages of migration resistance and extraction resistance, thereby improving the anti-ultraviolet aging ability of synthetic paper.

[0020] The (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide used in the present invention can capture free radicals and play a role in gas phase flame retardancy, while promoting the formation of a carbon layer, thereby improving the flame retardancy of synthetic paper. DETAILED DESCRIPTION

[0021] The invention will be further described below in conjunction with the embodiments, but the invention is not limited to these embodiments.

[0022] Example 1 Preparation of modified UV-resistant agent:

[0023] Add 2000g of DMF to the reaction bottle, stir and heat to 75°C, add 500g of 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate, 200g of (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, and 40g of dibenzoyl peroxide in sequence, react for 10h under nitrogen protection to obtain a reddish brown solution, rotary evaporate, and vacuum dry at 50°C for 8h to obtain a modified UV inhibitor.

[0024] Example 2 Preparation of modified UV-resistant agent:

[0025] Add 2500g DMF to the reaction bottle, stir and heat to 85°C, add 500g 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate, 250g (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, 60g dibenzoyl peroxide in sequence, react under nitrogen protection for 9h to obtain a reddish brown solution, rotary evaporate, vacuum dry at 55°C for 8h to obtain a modified UV inhibitor. Its H NMR spectrum data are as follows:

[0026] 1 H NMR (500 MHz, Chloroform- d ) δ12.21(s, 1H), 8.18 (ddd, J= 12.9,7.4, 1.3 Hz, 2H), 7.95 – 7.88 (m, 1H), 7.80 – 7.72 (m, 3H), 7.71 (d, J = 8.4Hz, 1H), 7.65 – 7.57 (m, 2H), 7.55 – 7.46 (m, 4H), 7.49 – 7.40 (m, 2H), 7.21 – 7.15 (m, 2H), 6.81 – 6.75 (m, 2H), 6.70 (dd, J = 8.3, 2.3 Hz, 1H), 6.45 (d, J = 2.3 Hz, 1H), 4.34 (dd, J = 11.8, 5.7 Hz, 1H), 4.23 (dd, J = 12.1, 5.7 Hz,1H), 4.12 – 3.94 (m, 3H), 3.78 – 3.71 (m, 1H), 3.52 (d, J = 6.3 Hz, 1H), 2.61– 2.46 (m, 2H), 2.43 (dt, J = 14.5, 8.6 Hz, 1H), 2.26 (dq, J = 13.4, 8.2 Hz,1H).

[0027] Example 3 Preparation of modified UV-resistant agent:

[0028] Add 3000g of DMF to the reaction bottle, stir and heat to 95°C, add 500g of 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate, 300g of (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, and 80g of dibenzoyl peroxide in sequence, react under nitrogen protection for 8h to obtain a reddish brown solution, rotary evaporate, and vacuum dry at 60°C for 6h to obtain a modified UV inhibitor.

[0029] Example 4

[0030] A UV-resistant polypropylene synthetic paper has a thickness of 0.20 mm, an outer layer and an inner layer both having a thickness of 0.06 mm, and a middle layer having a thickness of 0.08 mm; the outer layer comprises 4000 g of polypropylene, 2000 g of polypropylene carbonate, 200 g of a modified UV-resistant agent (prepared in Example 1), and 100 g of calcium carbonate; the middle layer comprises 2000 g of polypropylene, 3000 g of polypropylene carbonate, 200 g of a modified UV-resistant agent (prepared in Example 1), and 100 g of calcium carbonate; and the inner layer has the same raw materials and proportions as the outer layer.

[0031] Example 5

[0032] A UV-resistant polypropylene synthetic paper has a thickness of 0.20 mm, an outer layer and an inner layer having a thickness of 0.06 mm, and a middle layer having a thickness of 0.08 mm; the outer layer is made of the following raw materials: 4500 g of polypropylene, 2500 g of polypropylene carbonate, 300 g of a modified UV-resistant agent (prepared in Example 2), and 150 g of calcium carbonate; the middle layer is made of the following raw materials: 2500 g of polypropylene, 3500 g of polypropylene carbonate, 300 g of a modified UV-resistant agent (prepared in Example 2), and 150 g of calcium carbonate; and the inner layer has the same raw materials and proportions as the outer layer.

[0033] Example 6

[0034] A UV-resistant polypropylene synthetic paper has a thickness of 0.20 mm, an outer layer and an inner layer both having a thickness of 0.06 mm, and a middle layer having a thickness of 0.08 mm; the outer layer is made of the following raw materials: 5000 g of polypropylene, 3000 g of polypropylene carbonate, 400 g of a modified UV-resistant agent (prepared in Example 3), and 200 g of calcium carbonate; the middle layer is made of the following raw materials: 3000 g of polypropylene, 4000 g of polypropylene carbonate, 400 g of a modified UV-resistant agent (prepared in Example 3), and 200 g of calcium carbonate; and the raw materials and proportions of the inner layer are the same as those of the outer layer.

[0035] Comparative Example 1

[0036] A UV-resistant polypropylene synthetic paper is basically the same as Example 5, except that no modified UV-resistant agent is added to the outer layer and the inner layer.

[0037] Comparative Example 2

[0038] A UV-resistant polypropylene synthetic paper is basically the same as Example 5, except that the modified UV-resistant agent added to the outer layer and the inner layer is replaced by an equal weight of 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate.

[0039] Comparative Example 3

[0040] A UV-resistant polypropylene synthetic paper is basically the same as Example 5, except that the modified UV-resistant agent added to the outer layer and the inner layer is replaced by an equal weight of (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide.

[0041] Comparative Example 4

[0042] A UV-resistant polypropylene synthetic paper is basically the same as Example 5, except that the modified UV-resistant agent added to the outer layer and the inner layer is replaced by 200g of 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate and 100g of (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide.

[0043] Comparative Example 5

[0044] A UV-resistant polypropylene synthetic paper, wherein the raw materials and proportions of the outer layer, the middle layer and the inner layer are the raw materials and proportions of Example 1 of the Chinese invention patent with publication number CN104943308A.

[0045] The UV-resistant polypropylene synthetic paper of Examples 4-6 and Comparative Examples 1-5 was prepared by the following process:

[0046] S1: Extruding the outer layer raw material, the middle layer raw material and the inner layer raw material through an extruder respectively;

[0047] S2: extruding each layer of raw materials extruded by the extruder through a T-type die, and then longitudinally stretching and transversely stretching, followed by cooling, corona treatment, and trimming;

[0048] Among them, the extrusion temperature of the outer layer raw material and the inner layer raw material is 230°C, and the extrusion temperature of the middle layer raw material is 250°C; the preheating section temperature of longitudinal stretching is 130°C, the stretching section temperature is 142°C, the shaping section temperature is 145°C, the longitudinal stretching ratio is 4.9, the preheating section temperature of transverse stretching is 167°C, the stretching section temperature is 155°C, the shaping section temperature is 171°C, the transverse stretching ratio is 9 times, and the corona is 34.

[0049] The polypropylene used in the examples and comparative examples of the present application is CJS-700 homopolymer polypropylene produced by Sinopec, and the weight average molecular weight of polypropylene carbonate is 1.3×10 5 The brand of calcium carbonate is Qiagen KJ-106.

[0050] The polypropylene synthetic papers prepared in Examples 4-6 and Comparative Examples 1-5 were subjected to UV aging tests, and the test method was carried out according to the method of GB / T 16422.3-2014 "Plastics Laboratory Light Source Exposure Test Method".

[0051] The polypropylene synthetic paper prepared in Examples 4-6, Comparative Examples 1-5, and the aged polypropylene synthetic paper were subjected to tensile strength tests according to the method of GB13022-91; the test results of Examples 4-6 of the present application are shown in Table 1.

[0052] The polypropylene synthetic paper prepared in Examples 4-6 and Comparative Examples 1-5 and the aged synthetic paper were subjected to a vertical burning (UL-94) test. According to the ASTM D3801 standard, the vertical burning grade of the samples was evaluated using a CZF-3 instrument. The sample size was 130×13×3.2 mm 3 (Its thickness is achieved by stacking layers of synthetic paper). The test results are shown in Table 1.

[0053] Table 1

[0054]

[0055] It can be seen from Examples 4, 5 and 6 in Table 1 that the polypropylene synthetic paper prepared by the present invention has transverse and longitudinal mechanical strengths greater than 120 MPa and 75 MPa, respectively, and the transverse and longitudinal mechanical strengths after aging are greater than 110 MPa and 65 MPa, respectively, and has excellent transverse and longitudinal mechanical properties, and the flame retardant grade remains at V-0 level after aging.

[0056] Comparative Example 1 is a comparative example without adding an anti-ultraviolet agent. After aging, its transverse mechanical strength is lower than 81 MPa, its longitudinal tensile strength is 49 MPa, and its flammability rating (UL-94) is V-2.

[0057] Comparative Example 2 is different from Example 5, in that the modified UV inhibitor is replaced with 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate, and after aging, the transverse mechanical strength is 101 MPa, the longitudinal tensile strength is 60 MPa, and the flammability rating (UL-94) is V-2.

[0058] Comparative Example 3 is different from Example 5, and the difference is that the modified UV inhibitor is replaced with (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide. It can be seen from the data in Table 1 that the mechanical properties before aging are basically similar to those of Example 5, but after aging, the transverse tensile strength is 83 MPa, the longitudinal tensile strength is 50 MPa, the mechanical strength loss is serious, and the flammability rating (UL-94) is V-0.

[0059] Comparative Example 4 is different from Example 5, in that the modified UV inhibitor is replaced by 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate and (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide. After aging, the transverse mechanical strength is 96 MPa, the longitudinal tensile strength is 57 MPa, and the flammability rating (UL-94) is V-1.

[0060] Comparative Example 5 is a synthetic paper prepared using the raw materials and proportions in Example 1 of the Chinese invention patent with publication number CN104943308A. After aging, its transverse tensile strength is 88 MPa, its longitudinal tensile strength is less than 49 MPa, and its flammability rating (UL-94) is V-2.

[0061] In summary, it can be seen from the data of the comparative examples and embodiments in Table 1 that the UV-resistant polypropylene synthetic paper prepared by the present invention has excellent transverse and longitudinal mechanical properties, still maintains relatively good mechanical properties after aging, and has excellent flame retardant properties.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in the field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A UV-resistant polypropylene synthetic paper, comprising an outer layer, an intermediate layer and an inner layer, characterized in that: The outer layer is composed of the following raw materials in parts by weight: 40-50 parts of polypropylene, 20-30 parts of polypropylene carbonate, 2-4 parts of modified anti-ultraviolet agent, and 1-2 parts of calcium carbonate; The middle layer is composed of the following raw materials in parts by weight: 20-30 parts of polypropylene, 30-40 parts of polypropylene carbonate, 2-4 parts of modified anti-ultraviolet agent, and 1-2 parts of calcium carbonate; The raw materials and the number of portions of the inner surface layer are the same as those of the outer surface layer; The modified UV inhibitor is prepared by the following method: Add DMF to the reaction bottle, stir and heat to 75-95°C, add 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate, (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, and dibenzoyl peroxide in sequence, react for 8-10 hours under nitrogen protection to obtain a reddish brown solution, rotary evaporate, and vacuum dry at 50-60°C to obtain a modified UV inhibitor; The mass ratio of DMF, dibenzoyl peroxide, (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide, and 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate is (20-30):(0.4-0.8):(2-3):5; The structural formula of the 3-(4-benzoyl-3-hydroxyphenoxy)-2-hydroxypropyl acrylate is: ； The structural formula of the (6S)-6-(hydroxy(4-hydroxyphenyl)methyl)dibenzo[c,e][1,2]phosphazene 6-oxide is: 。 2. A method for preparing the UV-resistant polypropylene synthetic paper according to claim 1, characterized in that: The following steps are involved: S1: Extruding the outer layer raw material, the middle layer raw material and the inner layer raw material through an extruder respectively; S2: extruding each layer of raw materials extruded by the extruder through a T-type die, and then longitudinally stretching and transversely stretching, followed by cooling, corona treatment, and trimming; Among them, the extrusion temperature of the outer layer raw material and the inner layer raw material is 230°C, and the extrusion temperature of the middle layer raw material is 250°C; the preheating section temperature of longitudinal stretching is 130°C, the stretching section temperature is 142°C, the shaping section temperature is 145°C, the longitudinal stretching ratio is 4.9, the preheating section temperature of transverse stretching is 167°C, the stretching section temperature is 155°C, the shaping section temperature is 171°C, the transverse stretching ratio is 9 times, and the corona is 34.

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