Double-sided matting high-strength temperature-resistant white base film and preparation method thereof

Abstract

The invention discloses a double-sided matting high-strength temperature-resistant white base film and a preparation method thereof.The double-sided matting high-strength temperature-resistant white base film comprises a first matting surface layer, a white core layer and a second matting surface layer which are sequentially arranged from bottom to top, and the first matting surface layer and the second matting surface layer comprise matting master batches and high-temperature-resistant additives; the white core layer comprises high-temperature-resistant homopolymerized PP polypropylene, a white master batch, a stiffening agent and a functional master batch. According to the technical scheme, the white base film has excellent high-temperature resistance, the film surface is flat and smooth, the number of concave-convex points and foreign matter points is small, the surface is fine and uniform, the white base film is smooth in surface, little in static electricity, not prone to dust adsorption, good in surface tension maintaining and excellent in coating effect, the service life of the film is effectively prolonged, and the service life of the film is prolonged. The physical stability and the mechanical strength are high.

Description

Technical Field

[0001] The invention relates to the technical field of polypropylene films, and in particular to a double-sided matte high-strength temperature-resistant white base film and a preparation method thereof. Background Art

[0002] Biaxially oriented polypropylene film (BOPP) is generally a multi-layer co-extruded film, which is made by co-extruding polypropylene particles into sheets and then stretching them in both the longitudinal and transverse directions. Due to the orientation of the stretched molecules, this film has good physical stability, mechanical strength, and air tightness, high transparency and gloss, and is tough and wear-resistant. It is a widely used printing film, generally with a thickness of 20 to 40 μm, and the most widely used is 20 μm. The main disadvantage of biaxially oriented polypropylene film is poor heat sealing, so it is generally used as the outer film of composite film. For example, after being composited with polyethylene film, the moisture resistance, transparency, strength, stiffness and printability are ideal, and it is suitable for holding dry food. Since the surface of biaxially oriented polypropylene film is non-polar, with high crystallinity and low surface free energy, its printing performance is poor, and its adhesion to ink and adhesive is poor. Surface treatment is required before printing and lamination.

[0003] With the continuous improvement of global environmental awareness, environmentally friendly packaging materials have become the development trend of the packaging industry. As an important packaging material, BOPP film is widely used in many industries such as food, medicine, and cosmetics.

[0004] However, the haze of existing BOPP films on the market is generally above 1.5%, the transparency is poor, and the high temperature resistance of BOPP films is not ideal, so they are not suitable for the field of high-end BOPP films. Summary of the invention

[0005] The main purpose of the present invention is to provide a double-sided matte high-strength temperature-resistant white base film and a preparation method thereof, aiming to solve the technical problem of defects in the existing BOPP film mentioned in the above background technology.

[0006] To achieve the above-mentioned purpose, the double-sided matte high-strength and heat-resistant white base film proposed in the present invention comprises a first matte surface layer, a white core layer and a second matte surface layer arranged in sequence from bottom to top, the first matte surface layer and the second matte surface layer contain a matte masterbatch and a high-temperature resistant additive, and the white core layer contains a high-temperature resistant homopolymer PP polypropylene, a white masterbatch, a stiffener and a functional masterbatch.

[0007] Optionally, the first matte surface layer and the second matte surface layer contain 90% to 95% of a matte masterbatch and 5% to 10% of a high temperature resistant additive by weight percentage.

[0008] Optionally, the white core layer contains, by weight percentage, 78% to 84% of high temperature resistant PP polypropylene, 10% to 15% of white masterbatch, 3% to 5% of stiffening agent and 1% to 2% of functional masterbatch.

[0009] Optionally, the functional masterbatch is one or more of an antistatic agent and a lubricant.

[0010] Optionally, the thickness of the first matte surface layer is in the range of 1 μm to 5 μm.

[0011] Optionally, the thickness of the white core layer ranges from 10 μm to 90 μm.

[0012] Optionally, the thickness of the second matte surface layer is in the range of 1 μm to 5 μm.

[0013] On the other hand, the present invention also provides a method for preparing the double-sided matte high-strength and temperature-resistant white base film, the preparation method comprising the following steps: Raw material conveying: the raw material conveying unit conveys the polypropylene raw material particles in the silo into the batching unit through the feeding fan and the feeding valve, and removes impurities through the metal detector and dust removal device to ensure that the polypropylene raw material particles are uniform and free of impurities; Batching: The fully automatic batching system can digitally and accurately control the ratio of main materials and auxiliary materials according to the pre-proportioned ratio to ensure the stable and reliable quality of the film; Extrusion: The prepared raw materials are fed into the extrusion unit, which includes an extruder and two extruder auxiliary machines. The prepared polypropylene granule raw materials are fed into the extruder and the extruder auxiliary machines through the feeding port. Under high temperature and high pressure, the raw materials are gradually melted, plasticized and mixed through the shearing and extrusion of the screw rod, and the impurities and gel particles in the melt are removed through the filter. Casting sheet: The filtered melt enters the die head through the melt pipe and passes through the die lip under the pressure. Under the action of the air knife, the polypropylene melt flowing out of the die head in a viscous flow state is tightly attached to the surface of the chilling roller. The chilling roller is filled with flowing cooling water. Under the joint cooling of the air knife, the surface of the chilling roller and the water bath, the temperature drops to 20-35°C and is quickly cooled and cast into a sheet. Longitudinal stretching: the cooled sheet enters the longitudinal stretching device for longitudinal stretching. After preheating, longitudinal stretching and shaping, the sheet is longitudinally stretched by the stretching roller at a rate difference. Transverse stretching: After longitudinal stretching, the sheet enters the transverse stretching device for transverse stretching. After film feeding, preheating, transverse stretching, shaping and cooling, the transverse stretching process is completed to obtain a film with a width of 8.2 meters to 10.4 meters. Traction: The film obtained after transverse stretching enters the traction unit, where it is first cooled, flattened and trimmed, and the edge material is recycled. The film thickness is measured by an infrared thickness gauge, and the thickness measurement system is controlled to automatically adjust the lip opening of the T-die head according to the feedback information to ensure the stability of the film thickness. Corona treatment: corona discharge is carried out by a corona treatment machine. High-energy ions impact the film surface under the action of a strong electric field, and the surface tension is increased from the original 28 dynes to more than 40 dynes. The processed film is rolled up and finally rolled up by the tension control roller, flattening roller and tracking roller. The large film roll unloaded from the large film machine is aged on the aging rack for 2 to 3 days to eliminate the tensile stress. Film roll slitting: according to different specifications, the film roll will be cut into certain specifications on the slitting machine. The slit film rolls will be packaged and stored according to the standardized packaging process.

[0014] The technical solution of the present invention has the following beneficial effects: the technical solution of the present invention, through the first matte surface layer, the white core layer and the second matte surface layer arranged in sequence from bottom to top, the second matte surface layer is a corona layer, the first matte surface layer and the second matte surface layer contain homopolymer or copolymer PP polypropylene, antioxidant and anti-sticking masterbatch, the white core layer contains homopolymer PP polypropylene, PCR recycled plastic, antioxidant additives and functional masterbatch, so that the white base film has excellent high temperature resistance, and the film surface is flat and smooth, with few concave and convex points and foreign matter points, and the surface is delicate and uniform. Smooth, less static electricity, not easy to absorb dust, good surface tension, excellent coating effect, effectively improving the service life of the film, low gloss, high haze, delicate and balanced matte effect, and good transparency, and high physical stability and mechanical strength: Due to the orientation of stretched molecules, the white base film has good physical stability, mechanical strength and airtightness, high transparency and gloss, toughness and wear resistance, good light-shielding and printing properties, suitable for various printing needs, and can be widely used in high-end gift packaging, large outdoor advertising printing, hardcover book covers and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0016] Figure 1 This is a schematic diagram of a partially exploded structure of a double-sided matte, high-strength, and temperature-resistant white base film according to an embodiment of the present invention; Figure 2 The present invention is a flowchart of the overall steps of a method for preparing a double-sided matte high-strength and temperature-resistant white base film according to an embodiment of the present invention.

[0017] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0021] The invention provides a double-sided matte high-strength temperature-resistant white base film and a preparation method thereof.

[0022] like Figure 1 As shown, in one embodiment of the present invention, the double-sided matte high-strength and heat-resistant white base film includes a first matte surface layer 101, a white core layer 102 and a second matte surface layer 103 arranged in sequence from bottom to top, the first matte surface layer 101 and the second matte surface layer 103 contain a matte masterbatch and a high temperature resistant additive, and the white core layer 102 contains a high temperature resistant homopolymer PP polypropylene, a white masterbatch, a stiffener and a functional masterbatch.

[0023] Specifically, the first matte surface layer 101 and the second matte surface layer 103 contain 90% to 95% of matte masterbatch and 5% to 10% of high temperature resistant additives by weight percentage.

[0024] Specifically, by weight percentage, the white core layer 102 contains 78% to 84% of high temperature resistant PP polypropylene, 10% to 15% of white masterbatch, 3% to 5% of stiffening agent and 1% to 2% of functional masterbatch.

[0025] Specifically, the functional masterbatch is one or more of an antistatic agent and a lubricant.

[0026] Specifically, the thickness of the first matte surface layer 101 is in the range of 1 μm to 5 μm.

[0027] Specifically, the thickness of the white core layer 102 is in the range of 10 μm to 90 μm.

[0028] Specifically, the thickness of the second matte surface layer 103 is in the range of 1 μm to 5 μm.

[0029] On the other hand, Figure 2 As shown, the present invention also proposes a method for preparing the double-sided matte high-strength and temperature-resistant white base film, the preparation method comprising the following steps: S1: Raw material transportation: the raw material transportation unit delivers the polypropylene raw material particles in the silo into the batching unit through the feeding fan and the feeding valve, and removes impurities through the metal detector and dust removal device to ensure that the polypropylene raw material particles are uniform and free of impurities; S2: Batching: The fully automatic batching system can digitally and accurately control the ratio of main materials and auxiliary materials according to the pre-proportioned ratio to ensure stable and reliable film quality; S3: Extrusion, the prepared raw materials are fed into the extrusion unit, which includes an extruder and two extruder auxiliary machines. The prepared polypropylene granule raw materials are fed into the extruder and the extruder auxiliary machines through the feeding port. Under high temperature and high pressure, the raw materials are gradually melted, plasticized and mixed through the shearing extrusion of the screw rod, and the impurities and gel particles in the melt are removed through the filter. S4: Casting sheet: the filtered melt enters the die head through the melt pipe and passes through the die lip under the pressure. Under the action of the air knife, the polypropylene melt flowing out of the die head in a viscous flow state is tightly attached to the surface of the chilling roller. The chilling roller is filled with flowing cooling water. Under the joint cooling of the air knife, the chilling roller surface and the water bath, the temperature drops to 20-35°C and is quickly cooled and cast into a sheet. S5: longitudinal stretching: the cooled sheet enters the longitudinal stretching device for longitudinal stretching. After preheating, longitudinal stretching and shaping, the sheet is longitudinally stretched by the stretching roller in a multiplier speed difference manner. S6: Transverse stretching: the sheet after longitudinal stretching enters the transverse stretching device for transverse stretching treatment. After film feeding, preheating, transverse stretching, shaping and cooling steps, the transverse stretching process is completed to obtain a film with a width of 8.2 meters to 10.4 meters; S7: Traction, the film obtained after transverse stretching enters the traction unit, firstly undergoes cooling, flattening and trimming, and the edge material is recycled. The film thickness is measured by an infrared thickness gauge, and the thickness measurement system is controlled to automatically adjust the lip opening of the T-die head according to the feedback information to ensure the stability of the film thickness; S8: Corona treatment, corona discharge is carried out through the corona treatment machine, and high-energy ions impact the surface of the film under the action of a strong electric field, and the surface tension is increased from the original 28 dynes to more than 40 dynes; S9: Rewinding: The processed film is finally rolled up by the tension control roller, flattening roller and tracking roller, and the large film roll unloaded from the large film machine is aged on the aging rack for 2 to 3 days to eliminate the tensile stress; S10: Film roll slitting: according to different specifications, the film roll will be cut into certain specifications on the slitting machine. The slit film roll will be packaged and stored according to the standardized packaging process.

[0030] Specifically, the working principle of the present invention is: By sequentially arranging the first matte surface layer, the white core layer and the second matte surface layer from bottom to top, the second matte surface layer is a corona layer, the first matte surface layer and the second matte surface layer contain homopolymer or copolymer PP polypropylene, antioxidants and anti-sticking masterbatch, and the white core layer contains homopolymer PP polypropylene, PCR recycled plastics, antioxidant additives and functional masterbatch, so that the white base film has excellent high temperature resistance, and the film surface is flat and smooth, with few concave and convex points and foreign matter points, and the surface is delicate and uniform. The surface of the white base film is smooth, with less static electricity, not easy to absorb dust, and the surface tension is well maintained, the coating effect is excellent, and the service life of the film is effectively improved, and the low gloss, high haze, delicate and balanced matte effect, and good transparency, and the physical stability and mechanical strength are high: due to the orientation of the stretched molecules, the white base film has good physical stability, mechanical strength and airtightness, high transparency and gloss, toughness and wear resistance, good light-shielding and printing performance, and is suitable for various printing needs. It can be widely used in high-end gift packaging, large-scale outdoor advertising printing, hardcover book covers and other fields.

[0031] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A double-sided matte high-strength temperature-resistant white base film, characterized in that: It includes a first matte surface layer, a white core layer and a second matte surface layer which are arranged in sequence from bottom to top. The first matte surface layer and the second matte surface layer contain a matte masterbatch and a high temperature resistant additive. The white core layer contains a high temperature resistant homopolymer PP polypropylene, a white masterbatch, a stiffener and a functional masterbatch.

2. The double-sided matte high-strength temperature-resistant white base film according to claim 1, characterized in that: In terms of weight percentage, the first matte surface layer and the second matte surface layer contain 90% to 95% of a matte masterbatch and 5% to 10% of a high temperature resistant additive.

3. The double-sided matte high-strength temperature-resistant white base film according to claim 1, characterized in that: In terms of weight percentage, the white core layer contains 78% to 84% of high temperature resistant PP polypropylene, 10% to 15% of white masterbatch, 3% to 5% of stiffening agent and 1% to 2% of functional masterbatch.

4. The double-sided matte high-strength temperature-resistant white base film according to claim 1, characterized in that: The functional masterbatch is one or more of an antistatic agent and a lubricant.

5. The double-sided matte high-strength temperature-resistant white base film according to claim 1, characterized in that: The thickness of the first matte surface layer is in the range of 1 μm to 5 μm.

6. The double-sided matte high-strength temperature-resistant white base film according to claim 1, characterized in that: The thickness of the white core layer ranges from 10 μm to 90 μm.

7. The double-sided matte high-strength temperature-resistant white base film according to claim 1, characterized in that: The thickness of the second matte surface layer is in the range of 1 μm to 5 μm.

8. A method for preparing a double-sided matte high-strength and temperature-resistant white base film according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Raw material conveying: the raw material conveying unit conveys the polypropylene raw material particles in the silo into the batching unit through the feeding fan and the feeding valve, and removes impurities through the metal detector and dust removal device to ensure that the polypropylene raw material particles are uniform and free of impurities; Batching: The fully automatic batching system can digitally and accurately control the ratio of main materials and auxiliary materials according to the pre-proportioned ratio to ensure the stable and reliable quality of the film; Extrusion: The prepared raw materials are fed into the extrusion unit, which includes an extruder and two extruder auxiliary machines. The prepared polypropylene granule raw materials are fed into the extruder and the extruder auxiliary machines through the feeding port. Under high temperature and high pressure, the raw materials are gradually melted, plasticized and mixed through the shearing and extrusion of the screw rod, and the impurities and gel particles in the melt are removed through the filter. Casting sheet: The filtered melt enters the die head through the melt pipe and passes through the die lip under the pressure. Under the action of the air knife, the polypropylene melt flowing out of the die head in a viscous flow state is tightly attached to the surface of the chilling roller. The chilling roller is filled with flowing cooling water. Under the joint cooling of the air knife, the surface of the chilling roller and the water bath, the temperature drops to 20-35°C and is quickly cooled and cast into a sheet. Longitudinal stretching: the cooled sheet enters the longitudinal stretching device for longitudinal stretching. After preheating, longitudinal stretching and shaping, the sheet is longitudinally stretched by the stretching roller at a rate difference. Transverse stretching: After longitudinal stretching, the sheet enters the transverse stretching device for transverse stretching. After film feeding, preheating, transverse stretching, shaping and cooling, the transverse stretching process is completed to obtain a film with a width of 8.2 meters to 10.4 meters. Traction: The film obtained after transverse stretching enters the traction unit, where it is first cooled, flattened and trimmed, and the edge material is recycled. The film thickness is measured by an infrared thickness gauge, and the thickness measurement system is controlled to automatically adjust the lip opening of the T-die head according to the feedback information to ensure the stability of the film thickness. Corona treatment: corona discharge is carried out by a corona treatment machine. High-energy ions impact the film surface under the action of a strong electric field, and the surface tension is increased from the original 28 dynes to more than 40 dynes. The processed film is rolled up and finally rolled up by the tension control roller, flattening roller and tracking roller. The large film roll unloaded from the large film machine is aged on the aging rack for 2 to 3 days to eliminate the tensile stress. Film roll slitting: according to different specifications, the film roll will be cut into certain specifications on the slitting machine. The slit film rolls will be packaged and stored according to the standardized packaging process.

Images