High barrier anti-curl release film

Abstract

The application belongs to the field of release films, and discloses a high-barrier anti-curling release film. The release film comprises, from the surface to the inside, a surface layer, a secondary surface layer, an outer adhesive layer, a barrier layer, an inner adhesive layer, a secondary inner layer and an inner layer; the material of the barrier layer comprises PA6 and nylon MXD6, and / or the material of the inner layer comprises homopolymer polypropylene, copolymer polypropylene, EVOH and a compatibilizer. The application can guarantee the bonding strength of self-adhesive asphalt after heat aging.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of release films, and more particularly, to a high-barrier anti-curling release film. BACKGROUND

[0002] During storage and transportation in summer, the temperature of self-adhesive asphalt roll material can reach 60℃. If the release film does not have good barrier effect, the asphalt roll material will be subjected to thermal oxidative aging when stored at this temperature for a long time, resulting in a decrease in the bonding strength of the roll material to the base material and affecting the service life of the roll material.

[0003] The existing barrier type release film is divided into two types, namely, a coated type and a multi-layer co-extrusion type.

[0004] The coated type is coated with a barrier liquid, such as polyvinyl alcohol, PVDC, EVOH, etc., on one side of the release film. This method not only increases the production process of the release film, but also causes the barrier to fail due to the hydrolysis of polyvinyl alcohol and EVOH in the presence of water; PVDC is not environmentally friendly and cannot be recycled, and burning can produce carcinogens such as dioxins.

[0005] The multi-layer co-extrusion type adds a barrier layer material during production, and the barrier layer material is generally nylon 6 material. The multi-layer co-extrusion type release film has a simple production process, the material is easy to obtain, and the cost is controllable.

[0006] However:

[0007] Nylon 6 material is easily affected by air humidity, causing a decrease in gas barrier performance. For example, if the release film is stored in a humid environment in the south for one day, the gas barrier performance of nylon 6 material can be attenuated by more than 50%. This is because nylon 6 material contains amine groups and carbonyl groups, which can easily form hydrogen bonds with water molecules. After absorbing water, the spacing between nylon 6 molecular chains increases, forming more micropores and channels, which are conducive to the passage of gas, resulting in a decrease in the gas barrier performance of the release film.

[0008] In addition, due to the difference between different materials, the release film will curl towards the surface after being heated, causing the self-adhesive asphalt roll material to be directly exposed to the air, which further affects the service life of the roll material. The reason for the curling of the release film towards the surface after being heated is that the release film is a multi-layer co-extruded film, the barrier layer is nylon, and the surface layer and the inner layer are polypropylene or polyethylene. Olefin materials have poor oil resistance, and after being heated, the movement of oil in asphalt is intensified, and aromatic hydrocarbons in the oil can easily penetrate and swell olefin. However, the hydrogen bonds in the molecular structure of nylon are strong, and the crystallinity is high, so aromatic hydrocarbons cannot swell nylon, resulting in the swelling of the inner layer of polypropylene and the non-swelling of the surface layer of polypropylene. Therefore, the release film curls outward.

[0009] In summary, the barrier property of the release film nylon decreases, and the curling after aging causes the release film and the asphalt surface to delaminate, which are the main reasons for the decrease in the bonding strength of the self-adhesive asphalt roll material, therefore, it is urgent to provide a high-barrier anti-curling release film, and the barrier property is not affected by the environmental humidity, so as to ensure the bonding strength of the asphalt roll material and prolong the service life of the asphalt roll material. SUMMARY

[0010] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a high-barrier anti-curling release film.

[0011] In order to achieve the above-mentioned purpose, the present application provides a high-barrier anti-curling release film, which comprises a surface layer, a subsurface layer, an outer bonding layer, a barrier layer, an inner bonding layer, a subsurface layer and an inner layer arranged from the surface to the inside in sequence.

[0012] The material of the barrier layer comprises PA6 and nylon MXD6, and / or the material of the inner layer comprises homopolypropylene, copolypropylene, EVOH and a compatibilizer.

[0013] According to the present application, preferably, the material of the surface layer comprises 75-85% of homopolypropylene, 5-15% of copolypropylene and 5-10% of color master batch, based on the total weight of the surface layer.

[0014] In the present application, the materials of each layer of the release film of the present application, except the barrier layer and the inner and outer bonding layers, are a combination of homopolypropylene and copolypropylene, wherein homopolypropylene is the main component and copolypropylene is the auxiliary component, the main reason being that homopolypropylene has higher tensile strength and rigidity, and better heat resistance. The temperature is high during the production of the self-adhesive polymer asphalt waterproof roll material, which ensures that the release film will not wrinkle when it comes into contact with the roll material due to high temperature. Higher tensile strength ensures that the self-adhesive asphalt roll material will not be torn and broken during use, which will affect the construction. Copolypropylene has better toughness, which ensures better adhesion of the self-adhesive asphalt roll material during production, and improves the flatness of the film surface after storage. Better toughness helps to prevent the release film from being torn horizontally during the film tearing process. In summary, the use of homopolypropylene and copolypropylene blending can ensure the flatness of the film surface during production and storage, and also ensure the stability of the film tearing process.

[0015] In the present application, as a preferred solution, the color master batch used in the present application is a polypropylene carrier color master batch. Polypropylene is used as the carrier, and the color master batch has better compatibility with the main material, and is less likely to have color difference, crystal points, holes and other undesirable appearance phenomena during casting.

[0016] According to the present application, preferably, the material of the subsurface layer comprises 75-85% of homopolypropylene and 15-25% of copolypropylene, based on the total weight of the subsurface layer.

[0017] According to the present application, preferably, the material of the outer adhesive layer comprises copolymerized polypropylene 85-100% and homopolymerized polypropylene 0-15%, based on the total weight of the outer adhesive layer.

[0018] According to the present application, preferably, the material of the barrier layer comprises PA6 75-85% and nylon MXD6 15-25%, based on the total weight of the barrier layer.

[0019] In the present application, the viscosity of PA6 is 2-5 Pa·s; the viscosity of nylon MXD6 is 2-5 Pa·s.

[0020] In the present application, when the percentage content of nylon MXD6 in the barrier layer is 15-25%, the barrier effect and film forming effect are optimal, and the overall toughness and strength of the material are optimal.

[0021] In the present application, MXD6 and PA6 (nylon 6) are selected to increase the barrier property of the release film, which depends on the regular and compact molecular chain arrangement of MXD6, and the high crystallinity of MXD6, the compact and orderly molecular arrangement in the crystalline region, so that gas and water vapor molecules are difficult to penetrate, and there is a strong hydrogen bond between MXD6 molecules, which enhances the intermolecular interaction force, thereby limiting the penetration of small molecules.

[0022] In addition, by adding MXD6 nylon material in the barrier layer, the existing nylon 6 is modified by blending, which can also increase the stiffness of the release film and improve the coiled material curling. This is because: there is a benzene ring in MXD6, which increases the rigidity of the molecular chain, so that the material is not easy to bend and twist, and the structure of the benzene ring is relatively stable, which can enhance the heat resistance of MXD6, and the high crystallinity and more regular molecular chain structure of MXD6 also help to improve the anti-deformation ability of the material.

[0023] According to the present application, preferably, the material of the inner adhesive layer comprises copolymerized polypropylene 85-100% and homopolymerized polypropylene 0-15%, based on the total weight of the inner adhesive layer.

[0024] According to the present application, preferably, the material of the secondary inner layer comprises homopolymerized polypropylene 75-85% and copolymerized polypropylene 15-25%, based on the total weight of the secondary inner layer.

[0025] According to the present application, preferably, the material of the inner layer comprises homopolymerized polypropylene 20-40%, copolymerized polypropylene 30-40%, EVOH 15-25%, compatibilizer 5-10%, and color master batch 5-15%, based on the total weight of the inner layer.

[0026] In the present application, the mechanism of EVOH playing the oil blocking effect is that: EVOH molecules contain a large number of hydroxyl groups, so that it has strong polarity, while asphalt oil is a non-polar substance, the interaction between the two is weak, and oil is not easy to be adsorbed, and the hydroxyl group is easy to form hydrogen bond, and this hydrogen bond network makes the EVOH molecular structure more compact, so that the oil is more difficult to penetrate.

[0027] According to the present application, preferably, the compatilizer is PP-g-MAH and / or PE-g-MAH.

[0028] According to the present application, preferably, the release film is prepared by co-extrusion casting process.

[0029] According to the present application, preferably, the total thickness of the release film is 0.03mm-0.1mm, and the width is 950mm-1070mm.

[0030] According to the present application, preferably, the thickness ratio of each layer of the release film is: 10%-30% for the surface layer, 15%-25% for the subsurface layer, 5%-15% for the outer adhesive layer, 20%-30% for the barrier layer, 5%-15% for the inner adhesive layer, 15%-25% for the inner layer, and 10%-30% for the inner layer.

[0031] According to the present application, preferably, one side surface of the inner layer is heat-cured or UV-cured with a silicone oil layer, and the self-adhesive asphalt roll is bonded with the silicone oil layer.

[0032] According to the present application, preferably, the material of the silicone oil layer is at least one of methyl silicone oil, amino silicone oil, hydrogen-containing silicone oil and vinyl silicone oil.

[0033] According to the present application, preferably, the coating amount of the silicone oil layer is 0.5-1.5g / mm 2 .

[0034] In the present application, the surface layer, the subsurface layer, the inner layer and the inner layer:

[0035] The melt index of homopolymer polypropylene is 2-5g / 10min (230℃, 2.16kg);

[0036] The melt index of copolymer polypropylene is 5-10g / 10min (230℃, 2.16kg);

[0037] The melt index of color master batch is 5-10g / min (230℃, 2.16kg);

[0038] The melt index of EVOH is 5-10g / min (210℃, 2.16kg);

[0039] In the present application, the outer adhesive layer and the inner adhesive layer:

[0040] The melt index of the copolymerized polypropylene is 2-5 g / 10 min (230 DEG C, 2.16 kg).

[0041] The beneficial effects of the technical solutions of the present application are as follows:

[0042] The material of the barrier layer of the present application uses PA6 and nylon MXD6 in combination, PA6 has excellent gas barrier performance, but PA6 is easy to absorb water, which leads to a decrease in gas barrier performance, affecting the service life of the roll material, MXD6 has excellent gas barrier performance, and the barrier property is not affected by humidity, so the present application uses PA6 and MXD6 in combination, which increases the barrier performance of the release film, and the barrier performance is not affected by humidity, which can effectively prevent oxygen from penetrating, prevent self-adhesive asphalt roll material from aging, and affect the service life of the roll material.

[0043] The release film of the present application additionally adds 15-25% EVOH and 5-10% compatibilizer in the inner layer polypropylene and color master batch, which is to increase the oil resistance of polypropylene, because the polypropylene material does not have oil resistance, after heating, the oil in asphalt moves intensively, part of the oil penetrates and swells the polypropylene, however, nylon has high oil resistance, asphalt oil cannot continue to penetrate and swell, which leads to the swelling of the inner layer polypropylene, the surface layer polypropylene is not swollen, so the release film curls outward. Therefore, the release film of the present application adds EVOH with good barrier property and oil-repellent in the inner layer to prevent asphalt oil from penetrating and swelling the inner layer PP, prevent the release film from curling, and ensure that the self-adhesive asphalt roll material does not curl after being stored at 70 DEG C for seven days. Moreover, the present application uses PP and EVOH in the inner layer, rather than using EVOH as a barrier layer alone, which can not only achieve good oil resistance effect, but also reduce the material usage.

[0044] The present application uses PA6 and MXD6 in combination and adds EVOH in the inner layer, which can not only block oxygen and water vapor in the air, but also hinder the penetration of oil in asphalt outward, better protect the self-adhesive asphalt roll material, and prolong the service life of the self-adhesive asphalt roll material. The release film of the present application can ensure the bonding strength of the self-adhesive asphalt roll material after heat aging, and the bonding strength can be maintained above 98.4% after 7 days of oven aging at 70 DEG C.

[0045] Other features and advantages of the present application will be described in detail in the following specific embodiments. DETAILED DESCRIPTION

[0046] Preferred embodiments of the present application will be described in more detail below. Although the following describes preferred embodiments of the present application, it is to be understood that the application can be carried out in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0047] Example 1

[0048] The present embodiment provides a high-barrier anti-curl release film, which comprises, from top to bottom, a top layer, a sub-top layer, an outer adhesive layer, a barrier layer, an inner adhesive layer, a sub-inner layer, and an inner layer;

[0049] One side surface of the inner layer is UV-cured with a silicone oil layer, and a self-adhesive asphalt membrane is bonded to the silicone oil layer; the material of the silicone oil layer is methyl silicone oil, and the coating amount of the silicone oil layer is 0.8 g / mm 2 .

[0050] The release film is prepared by a co-extrusion casting process;

[0051] The total thickness of the release film is 0.03 mm, and the width is 1040 mm;

[0052] The thickness ratio of each layer of the release film is: top layer 18%, sub-top layer 18%, outer adhesive layer 7%, barrier layer 30%, inner adhesive layer 7%, sub-inner layer 10%, and inner layer 10%.

[0053] The material of the top layer includes homopolymer polypropylene (Sinopec K8003) 80%, copolymer polypropylene (Sinopec M800E) 10%, and gray masterbatch (Ningbo Color Masterbatch) 10%, based on the total weight of the top layer.

[0054] The material of the sub-top layer includes homopolymer polypropylene (Sinopec T30S) 80% and copolymer polypropylene (Sinopec K8009) 20%, based on the total weight of the sub-top layer.

[0055] The material of the outer adhesive layer is copolymer polypropylene (Mitsui Chemical QF551A), based on the total weight of the outer adhesive layer.

[0056] The material of the barrier layer includes PA6 (Yueyang Petrochemical YH3400) 85% and nylon MXD6 (Sinochem) 15%, based on the total weight of the barrier layer.

[0057] The material of the inner adhesive layer is copolymer polypropylene (Mitsui Chemical QF551A), based on the total weight of the inner adhesive layer.

[0058] The material of the secondary inner layer comprises homopolymer polypropylene (Sinopec T30S) 80% and copolymer polypropylene (Sinopec K8009) 20%, based on the total weight of the secondary inner layer.

[0059] The material of the inner layer comprises homopolymer polypropylene (Sinopec K8003) 30%, copolymer polypropylene (Sinopec M800E) 40%, EVOH (ethylene-vinyl alcohol copolymer, Mitsubishi D2908) 15%, PP-g-MAH (SK Chemical 18732) 5%, and black masterbatch (Miaocai) 10%, based on the total weight of the inner layer.

[0060] Example 2

[0061] The difference between this example and Example 1 is only that:

[0062] The material of the barrier layer comprises PA6 (Yueyang Petrochemical YH3400) 100%, based on the total weight of the barrier layer.

[0063] Example 3

[0064] The difference between this example and Example 1 is only that:

[0065] The material of the inner layer comprises homopolymer polypropylene (Sinopec K8003) 40%, copolymer polypropylene (Sinopec M800E) 50%, and black masterbatch (Miaocai) 10%, based on the total weight of the inner layer.

[0066] Comparative Example 1

[0067] This comparative example provides a release film, and the difference between this comparative example and Example 1 is only that:

[0068] The material of the barrier layer comprises PA6 (Yueyang Petrochemical YH3400) 100%, based on the total weight of the barrier layer.

[0069] The material of the inner layer comprises homopolymer polypropylene (Sinopec K8003) 40%, copolymer polypropylene (Sinopec M800E) 50%, and black masterbatch (Miaocai) 10%, based on the total weight of the inner layer.

[0070] Test Example

[0071] This test example tests the release films of the above examples and comparative examples.

[0072] The test methods are GB 23441-2009, GB / T 19789-2021, and GB / T 25256-2010.

[0073] The test results are shown in Table 1.

[0074] Table 1

[0075]

[0076] In combination with the above data, it can be seen that:

[0077] The addition of MXD6 can greatly improve the oxygen barrier performance of the release film, and the oxygen transmission rate changes little with the increase of humidity; and the addition of MXD6 also increases the tensile strength of the release film in the transverse and longitudinal directions.

[0078] The addition of EVOH in the inner layer of the release film can effectively improve the curling degree of the release film in the 70℃ oven.

[0079] Increasing the barrier performance of the release film or improving the curling degree of the release film can improve the bonding strength of the roll after aging at 70℃, and in combination with the improvement of the barrier performance and the curling degree, the best bonding strength can be obtained, and the bonding strength attenuation after aging is less than 1.6%.

[0080] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A high-barrier, anti-curl release film characterized by, The release film comprises, from the surface to the inside, a surface layer, a subsurface layer, an outer adhesive layer, a barrier layer, an inner adhesive layer, a subsurface inner layer and an inner layer; The material of the barrier layer comprises PA6 and nylon MXD6, and / or the material of the inner layer comprises homopolypropylene, copolypropylene, EVOH and a compatibilizer; The material of the surface layer comprises, based on the total weight of the surface layer, 75-85% homopolypropylene, 5-15% copolypropylene and 5-10% color masterbatch; The material of the subsurface layer comprises, based on the total weight of the subsurface layer, 75-85% homopolypropylene and 15-25% copolypropylene; The material of the outer adhesive layer comprises, based on the total weight of the outer adhesive layer, 85-100% copolypropylene and 0-15% homopolypropylene; The material of the inner adhesive layer comprises, based on the total weight of the inner adhesive layer, 85-100% copolypropylene and 0-15% homopolypropylene; The material of the subsurface inner layer comprises, based on the total weight of the subsurface inner layer, 75-85% homopolypropylene and 15-25% copolypropylene.

2. The high-barrier, anti-curl release film of claim 1, wherein, The material of the barrier layer comprises, based on the total weight of the barrier layer, 75-85% PA6 and 15-25% nylon MXD6.

3. The high-barrier, anti-curl release film of claim 1, wherein, The material of the inner layer comprises, based on the total weight of the inner layer, 20-40% homopolypropylene, 30-40% copolypropylene, 15-25% EVOH, 5-10% compatibilizer and 5-15% color masterbatch.

4. The high-barrier, anti-curl release film of claim 3, wherein, The compatibilizer is PP-g-MAH and / or PE-g-MAH.

5. The high-barrier anti-curl release film of claim 1, wherein, The release film is prepared by a co-extrusion casting process; The total thickness of the release film is 0.03-0.1 mm, and the width is 950-1070 mm; The thickness ratio of each layer of the release film is: 10-30% for the surface layer, 15-25% for the subsurface layer, 5-15% for the outer adhesive layer, 20-30% for the barrier layer, 5-15% for the inner adhesive layer, 15-25% for the subsurface inner layer, and 10-30% for the inner layer.

6. The high-barrier, anti-curl release film of claim 1, wherein, One side surface of the inner layer is heat-cured or UV-cured with a silicone oil layer, and the self-adhesive asphalt membrane is bonded to the silicone oil layer.

7. The high-barrier, anti-curl release film of claim 6, wherein, The material of the silicone oil layer is at least one of methyl silicone oil, amino silicone oil, hydrogen-containing silicone oil and vinyl silicone oil.

8. The high-barrier, anti-curl release film of claim 6, wherein, The coating amount of the silicone oil layer is 0.5 to 1.5 g / mm 2 .

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