Heat-seal coating film material and preparation method thereof

Abstract

The invention relates to the technical field of film preparation, and particularly discloses a heat-seal coating film material and a preparation method thereof. The heat-seal coating film material comprises a transparent layer 1, a transparent layer 2 and a transparent layer 3, the transparent layer 1 and the transparent layer 3 are both prepared from co-polypropylene, and the transparent layer 2 is prepared from homo-polypropylene; wherein the upper surfaces and the lower surfaces of the transparent layer 1, the transparent layer 2 and the transparent layer 3 are respectively coated with an ultraviolet adsorption coating. Researches show that the heat-seal coating film material has a good anti-ultraviolet effect, and the phenomena that a coating film turns yellow and the like can be avoided; in addition, the heat-seal coating film material disclosed by the invention also has relatively high tensile strength and elongation at break; particularly, the heat-seal coating film disclosed by the invention also has relatively low haze, so that the heat-seal coating film is ensured to have relatively good transparency; and meanwhile, the heat-seal coating film also has relatively good glossiness.

Description

Technical Field

[0001] The invention relates to the technical field of film preparation, and in particular to a heat-sealing coating film material and a preparation method thereof. Background Art

[0002] In the current packaging film field, due to the particularity and diversity of packaging materials, packaging films need to meet more and more special functions. The current packaging films are based on the principle similar to that of automobile glass films, but as packaging films, they are inelastic and have a fixed shape. The packaging materials and the film shape must match exactly. Once there is an error, packaging cannot be achieved, which causes a lot of packaging inconveniences. In addition, the existing packaging films need to meet the requirements of anti-ultraviolet rays. Summary of the invention

[0003] In order to overcome at least one of the technical problems existing in the prior art, the present invention provides a heat-sealing coating film material and a preparation method thereof.

[0004] The technical solution of the present invention is as follows:

[0005] The present invention first provides a heat-sealing coating film material, comprising a transparent layer 1, a transparent layer 2 and a transparent layer 3, wherein the transparent layer 1 and the transparent layer 3 are both made of copolymerized polypropylene, and the transparent layer 2 is made of homopolymerized polypropylene;

[0006] The upper and lower surfaces of the transparent layer 1 , the transparent layer 2 and the transparent layer 3 are coated with ultraviolet absorption coatings respectively.

[0007] Preferably, the ultraviolet absorption coating is obtained by coating with a coating liquid;

[0008] The coating liquid comprises the following components: water-based anti-ultraviolet additive, amine light stabilizer, nano-TiO2 and water.

[0009] Preferably, the thickness of the transparent layer 1 is 1.0-1.5 μm; the thickness of the transparent layer 2 is 40-90 μm; and the thickness of the transparent layer 3 is 1.0-1.5 μm.

[0010] Preferably, the surface of the transparent layer 1 is further subjected to surface corona treatment.

[0011] The present invention also provides a method for preparing the above-mentioned heat-sealing coating film material, which comprises the following steps:

[0012] (1) mixing the raw materials of transparent layer 1, transparent layer 2 and transparent layer 3, melt-extruding and casting to obtain transparent layer 1, transparent layer 2 and transparent layer 3 sheets;

[0013] (2) coating the upper and lower surfaces of the transparent layer 1, transparent layer 2 and transparent layer 3 sheets with a coating liquid respectively to obtain the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing an ultraviolet absorption coating;

[0014] (3) laminating the transparent layer 1, the transparent layer 2 and the transparent layer 3 sheets containing the ultraviolet absorption coating, firstly stretching them longitudinally, and then stretching them transversely to obtain a stretched film;

[0015] (4) The stretched film is trimmed and the thickness is measured, and then rolled, aged and slit to obtain the heat-sealed coating film material.

[0016] Preferably, the specific temperature of melt extrusion in step (1) is 250-260°C.

[0017] Preferably, the temperature of the casting in step (1) is 30-40°C.

[0018] Preferably, the specific conditions for the longitudinal stretching in step (3) are: longitudinal stretching at 120-135° C. by 4.8-5.1 times.

[0019] Preferably, the specific conditions for the transverse stretching in step (3) are: transverse stretching at 160-175° C. by 8.5-9.0 times.

[0020] Preferably, after trimming and measuring the thickness of the stretched film in step (4), the surface of the transparent layer 1 is subjected to surface corona treatment.

[0021] Beneficial effects: The present invention provides a new heat-sealing coating film material and a preparation method thereof; studies have shown that the heat-sealing coating film material has good anti-ultraviolet effect, which can avoid the occurrence of yellowing of the coating film and the like; in addition, the heat-sealing coating film material of the present invention also has high tensile strength and elongation at break; in particular, the heat-sealing coating film of the present invention also has low haze, ensuring that the heat-sealing coating film has good transparency; at the same time, the heat-sealing coating film also has good gloss.

[0022] Specifically referring to GB / T 1040.3, the heat-sealing coating film material prepared by the present invention has a tensile strength (MD) of 130-133 N / mm2 and a tensile strength (TD) of 256-270 N / mm 2 ; Its elongation at break (MD) is 182-188%, and its elongation at break (TD) is 52-60%; It has excellent mechanical properties. In addition, referring to GB / T 2410 standard, the haze of the environmentally friendly BOPP film prepared by the present invention is 1.92-2.09%; referring to GB / T8807 standard, the glossiness 45° of the environmentally friendly BOPP film prepared by the present invention is 86.2-88.3%. DETAILED DESCRIPTION

[0023] The present invention is further explained below in conjunction with specific examples, but the examples do not limit the present invention in any form.

[0024] Example 1 Preparation of heat-sealing coating film material

[0025] The heat-sealing coating film material comprises a transparent layer 1, a transparent layer 2 and a transparent layer 3, wherein the transparent layer 1 and the transparent layer 3 are both made of copolymerized polypropylene, and the transparent layer 2 is made of homopolymerized polypropylene; wherein the upper and lower surfaces of the transparent layer 1, the transparent layer 2 and the transparent layer 3 are respectively coated with ultraviolet absorption coatings, the thickness of the transparent layer 1 is 1.0 μm; the thickness of the transparent layer 2 is 40 μm; the thickness of the transparent layer 3 is 1.0 μm; and the surface of the transparent layer 1 is also subjected to surface corona treatment.

[0026] Preparation method:

[0027] (1) mixing the raw materials of transparent layer 1, transparent layer 2 and transparent layer 3, and then melting and extruding them through a twin-screw extruder, and then casting and forming transparent layer 1, transparent layer 2 and transparent layer 3 sheets; wherein the specific temperature of the melt extrusion is 250° C.; the temperature of the casting and forming is 30° C.;

[0028] (2) coating the upper and lower surfaces of the transparent layer 1, transparent layer 2 and transparent layer 3 sheets with a coating liquid respectively to obtain the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing an ultraviolet absorption coating; wherein the coating liquid comprises the following components: an aqueous anti-ultraviolet additive, an amine light stabilizer, nano-TiO2 and water;

[0029] (3) After the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing the ultraviolet absorption coating are laminated, they are first stretched longitudinally and then stretched transversely to obtain a stretched film; wherein the specific conditions for the longitudinal stretching are: longitudinal stretching by 4.8 times at 120° C.; and the specific conditions for the transverse stretching are: transverse stretching by 8.5 times at 160° C.;

[0030] (4) The stretched film is trimmed, the thickness is measured, and the surface is corona treated, and then rolled, aged, and slit to obtain the heat-sealed coating film material.

[0031] Example 2 Preparation of heat-sealing coating film material

[0032] The heat-sealing coating film material comprises a transparent layer 1, a transparent layer 2 and a transparent layer 3, wherein the transparent layer 1 and the transparent layer 3 are both made of copolymerized polypropylene, and the transparent layer 2 is made of homopolymerized polypropylene; wherein the upper and lower surfaces of the transparent layer 1, the transparent layer 2 and the transparent layer 3 are respectively coated with ultraviolet absorption coatings, the thickness of the transparent layer 1 is 1.5 μm; the thickness of the transparent layer 2 is 90 μm; the thickness of the transparent layer 3 is 1.5 μm; and the surface of the transparent layer 1 is also subjected to surface corona treatment.

[0033] Preparation method:

[0034] (1) mixing the raw materials of transparent layer 1, transparent layer 2 and transparent layer 3, and then melting and extruding them through a twin-screw extruder, and then casting and forming the transparent layer 1, transparent layer 2 and transparent layer 3 sheets; wherein the specific temperature of the melt extrusion is 260° C.; the temperature of the casting and forming is 40° C.;

[0035] (2) coating the upper and lower surfaces of the transparent layer 1, transparent layer 2 and transparent layer 3 sheets with a coating liquid respectively to obtain the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing an ultraviolet absorption coating; wherein the coating liquid comprises the following components: an aqueous anti-ultraviolet additive, an amine light stabilizer, nano-TiO2 and water;

[0036] (3) After laminating the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing the ultraviolet absorption coating, the sheets are first longitudinally stretched and then transversely stretched to obtain a stretched film; wherein the specific conditions for the longitudinal stretching are: longitudinal stretching by 5.1 times at 135° C.; and the specific conditions for the transverse stretching are: transverse stretching by 9.0 times at 175° C.;

[0037] (4) The stretched film is trimmed, the thickness is measured, and the surface is corona treated, and then rolled, aged, and slit to obtain the heat-sealed coating film material.

[0038] Example 3 Preparation of heat-sealing coating film material

[0039] The heat-sealing coating film material comprises a transparent layer 1, a transparent layer 2 and a transparent layer 3, wherein the transparent layer 1 and the transparent layer 3 are both made of copolymerized polypropylene, and the transparent layer 2 is made of homopolymerized polypropylene; wherein the upper and lower surfaces of the transparent layer 1, the transparent layer 2 and the transparent layer 3 are respectively coated with ultraviolet absorption coatings, the thickness of the transparent layer 1 is 1.2 μm; the thickness of the transparent layer 2 is 50 μm; the thickness of the transparent layer 3 is 1.2 μm; and the surface of the transparent layer 1 is also subjected to surface corona treatment.

[0040] Preparation method:

[0041] (1) mixing the raw materials of transparent layer 1, transparent layer 2 and transparent layer 3, and then melting and extruding them through a twin-screw extruder, and then casting and forming transparent layer 1, transparent layer 2 and transparent layer 3 sheets; wherein the specific temperature of the melting and extrusion is 255° C.; the temperature of the casting and forming is 35° C.;

[0042] (2) coating the upper and lower surfaces of the transparent layer 1, transparent layer 2 and transparent layer 3 sheets with a coating liquid respectively to obtain the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing an ultraviolet absorption coating; wherein the coating liquid comprises the following components: an aqueous anti-ultraviolet additive, an amine light stabilizer, nano-TiO2 and water;

[0043] (3) After the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing the ultraviolet absorption coating are laminated, they are first stretched longitudinally and then stretched transversely to obtain a stretched film; wherein the specific conditions for the longitudinal stretching are: longitudinal stretching by 5.0 times at 130° C.; the specific conditions for the transverse stretching are: transverse stretching by 8.8 times at 170° C.;

[0044] (4) The stretched film is trimmed, the thickness is measured, and the surface is corona treated, and then rolled, aged, and slit to obtain the heat-sealed coating film material.

[0045] Specifically referring to GB / T 1040.3, the tensile strength (MD) of the heat-sealing coating film material prepared in Examples 1 to 3 is 130 to 133 N / mm 2 , tensile strength (TD) is 256~270N / mm 2 ; Its elongation at break (MD) is 182-188%, and its elongation at break (TD) is 52-60%; It has excellent mechanical properties. In addition, referring to GB / T 2410 standard, the haze of the environmentally friendly BOPP film prepared by the present invention is 1.92-2.09%; referring to GB / T8807 standard, the glossiness 45° of the environmentally friendly BOPP film prepared by the present invention is 86.2-88.3%.

Claims

1. A heat-seal coating film material, comprising a transparent layer 1, a transparent layer 2 and a transparent layer 3, characterized in that: The transparent layer 1 and the transparent layer 3 are both made of copolymerized polypropylene, and the transparent layer 2 is made of homopolymerized polypropylene; The upper and lower surfaces of the transparent layer 1 , the transparent layer 2 and the transparent layer 3 are coated with ultraviolet absorption coatings respectively.

2. The heat-sealing coating film material according to claim 1, characterized in that: The ultraviolet absorption coating is obtained by coating with a coating liquid; The coating liquid comprises the following components: water-based anti-ultraviolet additive, amine light stabilizer, nano-TiO2 and water.

3. The heat-seal coating film material according to claim 1, characterized in that: The thickness of the transparent layer 1 is 1.0 to 1.5 μm; the thickness of the transparent layer 2 is 40 to 90 μm; and the thickness of the transparent layer 3 is 1.0 to 1.5 μm.

4. The heat-sealing coating film material according to claim 1, characterized in that: The surface of the transparent layer 1 is also subjected to surface corona treatment.

5. The method for preparing the heat-sealing coating film material according to claim 1, characterized in that: The following steps are included: (1) mixing the raw materials of transparent layer 1, transparent layer 2 and transparent layer 3, melt-extruding and casting to obtain transparent layer 1, transparent layer 2 and transparent layer 3 sheets; (2) coating the upper and lower surfaces of the transparent layer 1, transparent layer 2 and transparent layer 3 sheets with a coating liquid respectively to obtain the transparent layer 1, transparent layer 2 and transparent layer 3 sheets containing an ultraviolet absorption coating; (3) laminating the transparent layer 1, the transparent layer 2 and the transparent layer 3 sheets containing the ultraviolet absorption coating, firstly stretching them longitudinally, and then stretching them transversely to obtain a stretched film; (4) The stretched film is trimmed and the thickness is measured, and then rolled, aged and slit to obtain the heat-sealed coating film material.

6. The method for preparing the heat-seal coating film material according to claim 1, characterized in that: The specific temperature of melt extrusion in step (1) is 250-260°C.

7. The method for preparing the heat-seal coating film material according to claim 1, characterized in that: The temperature of the casting in step (1) is 30-40°C.

8. The method for preparing the heat-seal coating film material according to claim 1, characterized in that: The specific conditions for the longitudinal stretching in step (3) are: longitudinal stretching at 120-135° C. by 4.8-5.1 times.

9. The method for preparing the heat-sealable coating film material according to claim 1, characterized in that: The specific conditions for the transverse stretching in step (3) are: transverse stretching at 160-175° C. by 8.5-9.0 times.

10. The method for preparing the heat-sealable coating film material according to claim 1, characterized in that: In step (4), after trimming and measuring the thickness of the stretched film, the surface of the transparent layer 1 is subjected to surface corona treatment.