Highly transparent low shrinkage tpu film and its preparation method

Abstract

The application provides a high-transparency low-shrinkage TPU film and a preparation method thereof. The preparation raw material of the high-transparency low-shrinkage TPU film comprises the following components in parts by weight: 100 parts by weight of TPU particles, 30-60 parts by weight of polycarbonate, 0.1-0.5 parts by weight of (4-hydroxycyclohexyl)methyl) tert-butyl carbamate, 0.5-1 parts by weight of 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one and 1-3 parts by weight of an antioxidant. The shrinkage of the TPU film is as low as 0.1% or below, the TPU film has good transparency, the light transmittance is 98.5% or above, the mechanical strength is high, and the TPU film is suitable for multiple fields such as automobiles, household appliances, electrical instruments, mechanical industry and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and relates to a TPU film with high transparency and low shrinkage and a preparation method thereof. BACKGROUND

[0002] Polyurethane materials have application value in many fields such as automobiles, household appliances, electrical instruments, and mechanical industry, but its application is limited due to its easy warping and large shrinkage. Therefore, the preparation of low shrinkage materials is still a research focus in the field.

[0003] CN101759934A discloses a high-flow, high-toughness, low-shrinkage filled modified polypropylene material, which is prepared from the following raw materials in percentage by weight: polypropylene 45-80%, powdered polyethylene 5-18%, inorganic filler 8-25%, calcium salt whisker 5-12%, antioxidant 0.1-1%, and other additives 0-2%. The advantages of the present application are: 1. The dispersion ability of the inorganic filler in the composite material system is significantly improved by adding an appropriate amount of powdered polyethylene, thereby improving the flowability of the polypropylene composite material; 2. The toughness deficiency of the inorganic filler filled polypropylene material is overcome by using inorganic fillers with smaller particle size; 3. The calcium salt whisker is added to the extruder by lateral feeding, thereby maintaining the original aspect ratio characteristics of the whisker and fully exerting the role of the whisker in reducing shrinkage. However, the shrinkage of the present application still needs to be further reduced, and it cannot reduce the shrinkage of polyurethane materials.

[0004] CN112341801A discloses a low-shrinkage thermoplastic polyurethane elastomer. The preparation raw materials of the low-shrinkage thermoplastic polyurethane elastomer include the following components in percentage by weight: TPU particles 60-80%, polypropylene 10-20%, polyethylene 5-10%, calcium salt whisker 1-5%, glass fiber 1-5%, and antioxidant 0.5-2%. The thermoplastic polyurethane elastomer has a low shrinkage of 0.5% or less and good mechanical properties, and is suitable for use in many fields such as automobiles, household appliances, electrical instruments, and mechanical industry. However, the inorganic material is used to reduce the shrinkage of the present application, and there is still a compatibility problem between the inorganic material and the polymer material.

[0005] Therefore, it is of great significance to further develop low-shrinkage thermoplastic polyurethane materials in the field. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application aims to provide a TPU film with high transparency and low shrinkage and a preparation method thereof. The TPU film of the present application has high transparency and low shrinkage, good mechanical properties, and is suitable for use in many fields such as automobiles, household appliances, electrical instruments, and mechanical industry.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] In one aspect, the present application provides a high-transparency and low-shrinkage TPU film, and the preparation raw materials of the high-transparency and low-shrinkage TPU film comprise the following components in parts by weight:

[0009]

[0010] In the present application, both (4-hydroxycyclohexyl)methyl) tert-butyl carbamate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are used to reduce the shrinkage of the TPU film, and both of them have a small amount and good effect, and can be well compatible with the main material TPU and polycarbonate, so that the obtained TPU film not only has a low shrinkage, but also has a high transparency and a high mechanical strength, and is suitable for application in various fields, especially in the field of optoelectronics.

[0011] In the present application, the low shrinkage refers to a shrinkage value of less than 0.1% according to the method of ISO2577. In the present application, the high transparency refers to a light transmittance of more than 98.5% according to the method of GB / T2410-2008.

[0012] In the present application, in the preparation raw materials of the high-transparency and low-shrinkage TPU film, the TPU particles are polyester type TPU particles.

[0013] In the present application, in the preparation raw materials of the high-transparency and low-shrinkage TPU film, the amount of polycarbonate can be 30 parts by weight, 35 parts by weight, 38 parts by weight, 40 parts by weight, 45 parts by weight, 48 parts by weight, 50 parts by weight, 55 parts by weight, 58 parts by weight or 60 parts by weight.

[0014] Preferably, the weight average molecular weight of the polycarbonate is 30-80 million, for example, 30 million, 3.5 million, 4 million, 4.5 million, 5 million, 5.5 million, 5.8 million, 6 million, 6.5 million, 6.8 million, 7 million, 7.5 million, 7.8 million or 8 million.

[0015] In the present application, in the preparation raw materials of the high-transparency and low-shrinkage TPU film, the amount of (4-hydroxycyclohexyl)methyl) tert-butyl carbamate is 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight or 0.5 part by weight.

[0016] In the present application, the amount of 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one in the raw material for preparing the high-transparency low-shrinkage TPU film can be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight.

[0017] In the present application, the amount of antioxidant in the raw material for preparing the high-transparency low-shrinkage TPU film can be 1 part by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.5 parts by weight, 2.8 parts by weight, or 3 parts by weight.

[0018] Preferably, the antioxidant is any one of antioxidant 3114, antioxidant 1010, antioxidant 168, or antioxidant 618, or a combination of at least two thereof.

[0019] In another aspect, the present application provides a method for preparing the high-transparency low-shrinkage TPU film as described above, which comprises the following steps:

[0020] (1) mixing TPU particles, (4-hydroxycyclohexyl)methyl) tert-butyl carbamate, and an antioxidant, and feeding them into a twin-screw extruder from a main feeding port;

[0021] (2) mixing polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one, and feeding them into the twin-screw extruder from a side feeding port, and extruding to form the high-transparency low-shrinkage TPU film.

[0022] In the preparation method of the present application, by mixing TPU particles, (4-hydroxycyclohexyl)methyl) tert-butyl carbamate, and an antioxidant, and feeding them into a twin-screw extruder from a main feeding port, and mixing polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one, and feeding them into the twin-screw extruder from a side feeding port, the mechanical properties can be improved and the shrinkage rate can be reduced. If all the materials are mixed together and fed into the twin-screw extruder, the effect of reducing the shrinkage rate is not very ideal, and the shrinkage rate is slightly high. The inventors cannot explain the principle exactly, but it is found in the experiment that feeding them into the twin-screw extruder separately with one of the main materials can make the shrinkage rate lower.

[0023] Preferably, the rotation speed of the mixing in step (1) is 600-1000 r / min, for example, 600 r / min, 650 r / min, 700 r / min, 750 r / min, 800 r / min, 850 r / min, 900 r / min, 950 r / min, or 1000 r / min.

[0024] Preferably, the mixing time of step (1) is 15-30 min, for example 15 min, 18 min, 20 min, 23 min, 25 min, 28 min or 30 min.

[0025] Preferably, the rotation speed of the mixing of step (2) is 100-300 r / min, for example 100 r / min, 120 r / min, 150 r / min, 180 r / min, 200 r / min, 250 r / min, 280 r / min or 300 r / min.

[0026] Preferably, the mixing time of step (2) is 10-20 min, for example 10 min, 12 min, 14 min, 15 min, 17 min, 19 min or 20 min.

[0027] Preferably, the rotation speed of the extrusion of step (2) is 300-700 r / min, for example 300 r / min, 320 r / min, 350 r / min, 380 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min, 650 r / min or 700 r / min.

[0028] Preferably, the temperature of the feeding section of the twin-screw extruder during the extrusion of step (2) is 170-180℃ (for example 170℃, 172℃, 175℃, 178℃, 180℃), the temperature of the mixing section is 190-200℃ (for example 190℃, 192℃, 195℃, 198℃, 200℃), the temperature of the extrusion section is 210-220℃ (for example 210℃, 212℃, 215℃, 218℃, 220℃), and the temperature of the die head is 210-220℃ (for example 210℃, 212℃, 215℃, 218℃, 220℃).

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] In the present application, both (4-hydroxycyclohexyl)methyl)carbamic acid tert-butyl ester and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are used to reduce the shrinkage of TPU film, and the amount of the two is small, which can reduce the shrinkage of TPU film to below 0.1%, and the TPU film of the present application has good transparency, light transmittance is above 98.5%, high mechanical strength, and is suitable for many fields such as automobiles, household appliances, electrical instruments, mechanical industry, and is especially suitable for application in the field of optoelectronics. DETAILED DESCRIPTION

[0031] The technical solutions of the present application are further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0032] Embodiment 1

[0033] In this embodiment, a high-transparency low-shrinkage TPU film is provided, and the raw materials for preparing the high-transparency low-shrinkage TPU film include the following components in terms of weight fraction:

[0034]

[0035] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical Industry), and the antioxidant is antioxidant 3114.

[0036] The preparation method includes the following steps:

[0037] (1) The TPU particles, (4-hydroxycyclohexyl)methyl) carbamic acid tert-butyl ester, and the antioxidant are mixed at a rotation speed of 700 r / min for 20 min, and are added into a double-screw extruder from a main feeding port;

[0038] (2) The polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are mixed at a rotation speed of 200 r / min for 10 min, and are added into a double-screw extruder from a side feeding port, and are extruded and molded, wherein the rotation speed of the double-screw extruder during extrusion is 500 r / min, the feeding section temperature is 170℃, the mixing section temperature is 190℃, the extrusion section temperature is 210℃, and the die temperature is 220℃, to obtain the high-transparency low-shrinkage TPU film.

[0039] Embodiment 2

[0040] In this embodiment, a high-transparency low-shrinkage TPU film is provided, and the raw materials for preparing the high-transparency low-shrinkage TPU film include the following components in terms of weight fraction:

[0041]

[0042] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical Industry), and the antioxidant is antioxidant 1010.

[0043] The preparation method includes the following steps:

[0044] (1) the TPU particles, (4-hydroxycyclohexyl) methyl) tert-butyl carbamate and antioxidant are mixed at a rotating speed of 600 r / min for 30 min, and are added into the twin-screw extruder from the main feeding port;

[0045] (2) the polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are mixed at a rotating speed of 300 r / min for 10 min, are added into the twin-screw extruder from the side feeding port, and are extruded to form a high-transparency low-shrinkage TPU film, wherein the rotating speed of the twin-screw extruder is 700 r / min, the feeding section temperature is 180℃, the mixing section temperature is 200℃, the extruding section temperature is 220℃, and the die temperature is 220℃.

[0046] Example 3

[0047] In this example, a high-transparency low-shrinkage TPU film is provided, and the raw materials for preparing the high-transparency low-shrinkage TPU film comprise the following components in parts by weight:

[0048]

[0049] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical), and the antioxidant is antioxidant 168.

[0050] The preparation method comprises the following steps:

[0051] (1) the TPU particles, (4-hydroxycyclohexyl) methyl) tert-butyl carbamate and antioxidant are mixed at a rotating speed of 1000 r / min for 15 min, and are added into the twin-screw extruder from the main feeding port;

[0052] (2) the polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are mixed at a rotating speed of 100 r / min for 20 min, are added into the twin-screw extruder from the side feeding port, and are extruded to form a high-transparency low-shrinkage TPU film, wherein the rotating speed of the twin-screw extruder is 300 r / min, the feeding section temperature is 170℃, the mixing section temperature is 200℃, the extruding section temperature is 210℃, and the die temperature is 220℃.

[0053] Example 4

[0054] In this example, a high-transparency low-shrinkage TPU film is provided, and the raw materials for preparing the high-transparency low-shrinkage TPU film comprise the following components in parts by weight:

[0055]

[0056]

[0057] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical), and the antioxidant is antioxidant 3114.

[0058] The preparation method comprises the following steps:

[0059] (1) The TPU particles, (4-hydroxycyclohexyl) methyl) tert-butyl carbamate, and the antioxidant are mixed at a rotating speed of 800 r / min for 25 min, and are added into a double screw extruder from a main feeding port;

[0060] (2) The polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are mixed at a rotating speed of 200 r / min for 15 min, are added into a double screw extruder from a side feeding port, and are extruded and molded, wherein the rotating speed of the double screw extruder is 500 r / min during extrusion, the feeding section temperature is 180 ℃, the mixing section temperature is 190 ℃, the extrusion section temperature is 210 ℃, and the die head temperature is 220 ℃, to obtain the high-transparency and low-shrinkage TPU film.

[0061] Example 5

[0062] In this embodiment, a high-transparency and low-shrinkage TPU film is provided, and the preparation raw materials of the high-transparency and low-shrinkage TPU film comprise the following components in terms of weight fractions:

[0063]

[0064] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical), and the antioxidant is antioxidant 1010.

[0065] The preparation method comprises the following steps:

[0066] (1) The TPU particles, (4-hydroxycyclohexyl) methyl) tert-butyl carbamate, and the antioxidant are mixed at a rotating speed of 700 r / min for 20 min, and are added into a double screw extruder from a main feeding port;

[0067] (2) The polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are mixed at a rotating speed of 200 r / min for 20 min, are added into a double screw extruder from a side feeding port, and are extruded and molded, wherein the rotating speed of the double screw extruder is 400 r / min during extrusion, the feeding section temperature is 170 ℃, the mixing section temperature is 190 ℃, the extrusion section temperature is 220 ℃, and the die head temperature is 220 ℃, to obtain the high-transparency and low-shrinkage TPU film.

[0068] Embodiment 6

[0069] In the embodiment, a high-transparency and low-shrinkage TPU film is provided, and raw materials for preparing the high-transparency and low-shrinkage TPU film include the following components in terms of weight fraction:

[0070]

[0071] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight-average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical Industry), and the antioxidant is antioxidant 618.

[0072] The preparation method includes the following steps:

[0073] (1) The TPU particles, (4-hydroxycyclohexyl)methyl) tert-butyl carbamate, and the antioxidant are mixed at a rotation speed of 1000 r / min for 15 min, and are added into a double-screw extruder from a main feeding port;

[0074] (2) The polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one are mixed at a rotation speed of 300 r / min for 10 min, and are added into the double-screw extruder from a side feeding port, and are extruded and molded, wherein the rotation speed of the double-screw extruder is 700 r / min during the extrusion, the feeding section temperature is 170°C, the mixing section temperature is 200°C, the extrusion section temperature is 210°C, and the die temperature is 220°C, to obtain the high-transparency and low-shrinkage TPU film.

[0075] Embodiment 7

[0076] In the embodiment, a high-transparency and low-shrinkage TPU film is provided, and raw materials for preparing the high-transparency and low-shrinkage TPU film include the following components in terms of weight fraction:

[0077]

[0078] The TPU particles are polyester TPU particles (Bayer 5377, Germany), the weight-average molecular weight of the polycarbonate is 40,000 (Chatian Tongda Chemical Industry), and the antioxidant is antioxidant 3114.

[0079] The preparation method includes the following steps:

[0080] (1) The TPU particles, (4-hydroxycyclohexyl)methyl) tert-butyl carbamate, and the antioxidant are mixed at a rotation speed of 600 r / min for 30 min, and are added into a double-screw extruder from a main feeding port;

[0081] (2) The polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl- butan-1-one were mixed at 200 r / min for 10 min, and then fed into the twin-screw extruder from the side feeding port, and then extruded, wherein the rotating speed of the twin-screw extruder was 600 r / min, the feeding section temperature was 180°C, the mixing section temperature was 190°C, the extruding section temperature was 210°C, and the die head temperature was 220°C, to obtain the TPU film with high transparency and low shrinkage.

[0082] Comparative Example 1

[0083] In this comparative example, the only difference from Example 1 is that no (4-hydroxycyclohexyl)methyl) tert-butylcarbamate was added in the raw materials for preparing the TPU film, and the amount of 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one was 0.6 parts by weight.

[0084] Comparative Example 2

[0085] In this comparative example, the only difference from Example 1 is that no 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one was added in the raw materials for preparing the TPU film, and the amount of (4-hydroxycyclohexyl)methyl) tert-butylcarbamate was 0.6 parts by weight.

[0086] Comparative Example 3

[0087] In this comparative example, the only difference from Example 1 is that the preparation method is as follows:

[0088] (1) The TPU particles, polycarbonate, (4-hydroxycyclohexyl)methyl) tert-butylcarbamate, 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butan-1-one, and antioxidant were mixed at 700 r / min for 20 min, and then fed into the twin-screw extruder from the main feeding port;

[0089] (2) Extrusion molding, wherein the rotating speed of the twin-screw extruder was 500 r / min, the feeding section temperature was 170°C, the mixing section temperature was 190°C, the extruding section temperature was 210°C, and the die head temperature was 220°C, to obtain the TPU film.

[0090] The TPU films of Examples 1-7 and Comparative Examples 1-3 were tested for performance, and the testing methods were as follows:

[0091] (1) The shrinkage was tested according to the method of ISO2577, and the sample size was 150 x 100 x 3.2 mm;

[0092] (2) The bending property test is performed according to the method of ISO 178, the sample size is 80x10x4mm, the bending speed is 2mm / min, and the span is 64mm;

[0093] (3) The Charpy impact strength is performed according to ISO 179, the sample size is 80x6x4mm, and the notch depth is one third of the sample thickness;

[0094] (4) The light transmittance is tested according to the method of GB / T 2410-2008.

[0095] The performance test results are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] As shown in Table 1, the shrinkage of the TPU film is less than 0.1%, the bending modulus is 1400-1478MPa, the notched impact strength at 23℃ is 25-32KJ / m 2 , the notched impact strength at -20℃ is 3.7-4.2KJ / m 2 , and the light transmittance is more than 98.6%, which has low shrinkage, high transparency and good mechanical properties.

[0100] The applicant declares that the high transparent low shrinkage TPU film of the present application is illustrated by the above examples, but the present application is not limited to the above examples, that is, it does not mean that the present application must rely on the above examples to be implemented. The skilled in the art should understand that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific mode, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A high transparent low shrinkage TPU film with shrinkage reduced to 0.1% or less, characterized in that, The raw material for preparing the high-transparent low-shrinkage TPU film consists of the following components by weight: The preparation method of the TPU film comprises the following steps: (1) mixing TPU particles, (4-hydroxycyclohexyl)methyl) aminomethyl tert-butyl and an antioxidant, and feeding them into a double-screw extruder from a main feeding port; (2) mixing polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butane-1-one, and feeding them into the double-screw extruder from a side feeding port, and extruding to obtain the high-transparent low-shrinkage TPU film; In step (2), the feeding section temperature of the double-screw extruder during extrusion is 170-180℃, the mixing section temperature is 190-200℃, the extrusion section temperature is 210-220℃, and the die temperature is 210-220℃.

2. The TPU film according to claim 1, characterized in that, The TPU particles are polyester TPU particles.

3. The TPU film of claim 1, wherein, The weight average molecular weight of the polycarbonate is 30-80 thousand.

4. The TPU film of claim 1, wherein, The antioxidant is any one or a combination of at least two of antioxidant 3114, antioxidant 1010, antioxidant 168 or antioxidant 618.

5. The method of claim 1-4, wherein, The preparation method comprises the following steps: (1) mixing TPU particles, (4-hydroxycyclohexyl)methyl) aminomethyl tert-butyl and an antioxidant, and feeding them into a double-screw extruder from a main feeding port; (2) mixing polycarbonate and 1-(2,4-dihydroxy-3-trifluoromethyl-phenyl)-3-methyl-butane-1-one, and feeding them into the double-screw extruder from a side feeding port, and extruding to obtain the high-transparent low-shrinkage TPU film.

6. The preparation method according to claim 5, characterized in that, In step (1), the rotation speed of the mixing is 600-1000 r / min.

7. The preparation method according to claim 5, characterized in that, In step (1), the mixing time is 15-30 min.

8. The preparation method according to claim 5, characterized in that, In step (2), the rotation speed of the mixing is 100-300 r / min.

9. The preparation method according to claim 5, characterized in that, In step (2), the mixing time is 10-20 min.

10. The method of claim 5, wherein, In step (2), the rotation speed of the double-screw extruder during extrusion is 300-700 r / min.

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