BOPP (biaxially-oriented polypropylene) cigarette stay wire base film capable of being subjected to color printing, gold plating and laser

Abstract

The invention relates to the technical field of BOPP films, and discloses a BOPP cigarette stay wire base film capable of being subjected to color printing, gold plating and laser. The composite material is prepared by directly co-extruding and compounding an upper surface layer, a core layer and a lower surface layer, wherein the upper surface layer comprises co-polypropylene and an anti-sticking master batch; the core layer comprises homo-polypropylene, an antistatic master batch and a stiffening agent master batch; and the lower surface layer comprises co-polypropylene and an anti-sticking master batch. The upper surface layer and the lower surface layer are made of pure terpolymer materials, the lower surface layer is made of small-particle-size inorganic silica master batch, and meanwhile the laser mold pressing function is improved by increasing the thickness of the lower surface layer. And the core layer is made of the ethoxy amine antistatic master batch, so that the digestion of surface tension is slowed down, the opening property of the finished film roll is improved, and downstream customers can conveniently and smoothly use the film roll. Through balanced design and selection of various materials, the indexes of the BOPP cigarette stay wire base film in the aspects of wire strength, shrinkage, haze, friction coefficient and the like meet the requirements of downstream stay wire enterprises.

Description

Technical Field

[0001] The invention belongs to the technical field of BOPP films, and in particular relates to a BOPP cigarette drawing base film which can be color-printed, gold-plated and laser-plated. Background Art

[0002] With the rapid development of my country's tobacco industry, the technical requirements for cigarette packaging materials are also constantly improving. As one of the key auxiliary materials for cigarette packaging, the quality of the drawstring is directly related to the consumer's experience and the anti-counterfeiting effect of the product. The drawstring makes the film packaging of cigarettes easy to tear, improving the consumer's experience. Other drawstrings besides transparent drawstrings also have anti-counterfeiting effects. From the initial golden drawstring, to the later printed drawstring, to the current laser drawstring, the technical threshold for anti-counterfeiting is getting higher and higher.

[0003] The wire drawing base film is the core of the wire drawing. Gold plating, printing, laser and glue coating all depend on the base film material. Traditional wire drawing base film materials mainly include PE, PET and BOPP, among which BOPP is the most widely used due to its excellent comprehensive performance. Although PE and PET have lower costs, they cannot be used on hard box cigarette packs, so their scope of use is not large. In addition, the existing wire drawing base film technology has problems such as unstable performance, insufficient anti-counterfeiting effect, and difficult processing to a certain extent.

[0004] While existing wire-drawing base film materials meet basic usage requirements, they often ignore anti-counterfeiting functions. Although gold-colored wires, printed wires, etc. have anti-counterfeiting effects to a certain extent, the technical threshold is low and they are easy to be counterfeited. Existing wire-drawing base films have certain limitations in material selection and processing technology, resulting in large fluctuations in product line strength, shrinkage, haze and other indicators, making it difficult to meet the needs of downstream wire-drawing companies. In the existing technology, the application of laser technology is not yet common, and the stability of the laser effect needs to be improved. In addition, the application of laser molding function in wire-drawing base films is not yet mature.

[0005] In view of this, we propose a BOPP cigarette wire-drawing base film that can be color-printed, gold-plated and laser-coated. Summary of the invention

[0006] The present invention aims to solve the technical problems that the above-mentioned prior art has insufficient anti-counterfeiting function and is easy to be counterfeited, the material performance stability is poor and it is difficult to meet the processing requirements, and the laser technology is not widely used and the effect stability needs to be improved.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser, which is made of a three-layer structure of an upper surface layer, a core layer and a lower surface layer, which is directly co-extruded and compounded;

[0009] The components of the upper surface layer are calculated by weight: 95-98 parts by weight of copolymerized polypropylene and 2-5 parts by weight of anti-sticking masterbatch;

[0010] The components of the core layer are calculated by weight: 71-79 parts by weight of homopolymer polypropylene, 1-4 parts by weight of antistatic masterbatch, and 20-25 parts by weight of rigidity-enhancing masterbatch;

[0011] The components of the lower surface layer are calculated by weight: 95-98 parts by weight of copolymerized polypropylene and 2-5 parts by weight of anti-sticking masterbatch.

[0012] Preferably, the copolymer polypropylene used for the upper and lower surface layers is pure ternary copolymer polypropylene, the main components of which are C2, C3, and C4, and the melting point is 134°C. The copolymer polypropylene material does not contain trace amounts of lubricating or anti-sticking additives, ensuring that the microscopic film surface is clean and smooth during laser molding.

[0013] Preferably, the carrier of the anti-sticking masterbatch used in the upper surface layer is copolymerized polypropylene, and the concentration of silicone oil-modified silica particles in the anti-sticking masterbatch is 5% and the particle size is 4 um.

[0014] Preferably, the carrier of the anti-sticking masterbatch used in the lower surface layer is copolymerized polypropylene, and the concentration of silicone oil-modified silica particles in the anti-sticking masterbatch is 5% and the particle size is 2 um.

[0015] Preferably, the carrier of the antistatic masterbatch used in the core layer is homopolypropylene, and the active ingredient of the antistatic masterbatch is ethoxylated amine with a concentration of 10%.

[0016] Preferably, the carrier of the rigidity-enhancing masterbatch used in the core layer is homopolymerized polypropylene, and the effective component of the rigidity-enhancing masterbatch is a hydrogenated resin with a benzene ring structure, and the concentration is 50%.

[0017] Preferably, the total thickness of the BOPP cigarette stretched base film is 33um, wherein the thickness of the upper surface layer is 1um, the thickness of the core layer is 30um, and the thickness of the lower surface layer is 2um.

[0018] A small amount of anti-sticking masterbatch is added to the upper and lower surface layers, and the particle sizes of the two are different. The wire-drawing base film needs to be subjected to strong corona treatment during the production process to meet the subsequent process requirements such as gluing, printing or gold plating, so the finished film roll is more likely to be sticky and generate static electricity. Adding anti-sticking masterbatch is the best choice. Laser molding has strict requirements on the microscopic film surface, so the lower surface layer uses a small-particle anti-sticking masterbatch to minimize its negative impact. The upper surface layer uses a large-particle anti-sticking masterbatch to enhance the opening of the finished film roll.

[0019] A small amount of antistatic masterbatch and an appropriate amount of stiffening masterbatch are added to the core layer. The less antistatic masterbatch, the better, and materials with slower migration speed are preferred to reduce the negative effect on corona treatment. The stiffening masterbatch is mainly used to increase the shrinkage rate of the wire drawing base film, and it is consistent with the BOPP film for hard box cigarettes during use to reduce the deformation of cigarette packages.

[0020] A method for preparing a BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing comprises the following steps:

[0021] S1. The raw materials of the core layer are mixed evenly and dried, and then enter the melting single screw extruder and the metering single screw extruder in series for melting and plasticization, and then enter the die head through the filter. The temperature of each section is set to: 220-250℃, and the melt temperature is 210-270℃;

[0022] S2, the raw materials of the upper surface layer and the lower surface layer are mixed evenly and dried, and then enter their respective single-screw extruders for melt plasticization, and then enter the die head through the filter. The temperature of each section is set to: 220-240℃, and the melt temperature is 220-250℃;

[0023] S3. The three layers of polymer melt flow out after converging at the die head, and under the action of the air knife attachment device, they adhere to the surface of the quench roller, and are quickly cooled by the quench roller and the water tank to form a solid casting sheet, which is then stretched longitudinally and transversely in sequence. The longitudinal preheating temperature is 110-130°C, the stretching temperature is 80-100°C, the setting temperature is 80-100°C, and the longitudinal stretching ratio is 5.0-7.0; the transverse preheating temperature is 170-190°C, the stretching temperature is 140-160°C, the transverse stretching ratio is 8-10, the setting temperature is 150-170°C, and the time is 1-3 seconds; the stretched BOPP film needs to be air-cooled immediately, and the cold air temperature is 10-20°C;

[0024] S4, after the transverse stretching process, it goes through the production processes such as online thickness measurement, edge material cutting, corona treatment, static elimination, automatic winding, aging treatment, etc.

[0025] S5. Cut into finished films of corresponding specifications according to the customer's specific requirements.

[0026] Compared with the prior art, the technical effects and advantages of the present invention are:

[0027] The BOPP cigarette wire base film that can be color-printed, gold-plated and laser-coated uses copolymerized polypropylene as the base material for the upper and lower surfaces, which improves the purity and heat-sealing performance of the material, while increasing the thickness of the lower surface to enhance the laser effect. The selection of anti-sticking masterbatch and antistatic masterbatch is optimized to make the material perform better in terms of transparency and surface tension maintenance. The introduction of laser molding technology improves the anti-counterfeiting effect of the wire base film to meet customers' needs for innovation and diversification. Through the balanced design and selection of various materials, the linear strength, shrinkage, haze and friction coefficient of the BOPP wire base film are more stable, meeting the requirements of downstream wire companies.

[0028] The line strength, elongation and shrinkage of the BOPP cigarette wire base film that can be color-printed, gold-plated and laser-coated meet the requirements for wire use. Because the structure, composition, purity, particle size and dosage of various materials are strictly designed, the microscopic film surface of the BOPP cigarette wire base film that can be color-printed, gold-plated and laser-coated meets the requirements of laser molding, and the laser pattern is clear and bright, which is recognized by customers. Because the appropriate amount of antistatic and anti-sticking masterbatch is added, the finished film roll is unwound smoothly in subsequent processing and has excellent performance on the machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The diagram is a three-layer structure diagram of a BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to the present invention.

[0030] In the figure: 1, upper surface layer; 2, core layer; 3, lower surface layer. DETAILED DESCRIPTION

[0031] 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.

[0032] Example 1

[0033] like Figure 1 As shown, a BOPP cigarette wire-drawing base film that can be color-printed, gold-plated and laser-plated is made by directly co-extruding and compounding a three-layer structure of an upper surface layer 1, a core layer 2 and a lower surface layer 3.

[0034] The components of the upper surface layer 1 are calculated by weight: 97 parts by weight of copolymerized polypropylene and 3 parts by weight of anti-sticking masterbatch; the carrier of the anti-sticking masterbatch is copolymerized polypropylene, and the effective component of the anti-sticking masterbatch is silicon dioxide particles with a particle size of 4 um and a concentration of 5%.

[0035] The components of the core layer 2 are calculated by weight: 79 parts by weight of homopolypropylene, 1 part by weight of antistatic masterbatch, and 20 parts by weight of stiffening masterbatch. The carrier of the antistatic masterbatch is homopolypropylene, and the active ingredient of the antistatic masterbatch is ethoxylated amine with a concentration of 10%.

[0036] The components of the lower surface layer 3 are calculated by weight: 97 parts by weight of copolymerized polypropylene and 3 parts by weight of anti-sticking masterbatch;

[0037] A production process of a BOPP cigarette draw-wire base film capable of color printing, gold plating and laser processing comprises the following steps:

[0038] After being mixed evenly and dried, the raw materials of S1 and core layer 2 enter the series-connected melting single screw extruder and metering single screw extruder for melting and plasticization, and then pass through the filter to enter the die head. The temperature of each section is set to: 220-250℃, and the melt temperature is 210-270℃;

[0039] After being mixed evenly and dried, the raw materials of S2, upper surface layer 1 and lower surface layer 3 enter their respective single screw extruders for melt plasticization, and then enter the die head through the filter. The temperature of each section is set to: 220-240°C, and the melt temperature is 220-250°C;

[0040] S3. The three layers of polymer melt flow out after converging at the die head, and under the action of the air knife attachment device, they adhere to the surface of the quench roller, and are quickly cooled by the quench roller and the water tank to form a solid casting sheet, which is then stretched longitudinally and transversely in sequence. The longitudinal preheating temperature is 110-130°C, the stretching temperature is 80-100°C, the setting temperature is 80-100°C, and the longitudinal stretching ratio is 5.0-7.0; the transverse preheating temperature is 170-190°C, the stretching temperature is 140-160°C, the transverse stretching ratio is 8-10, the setting temperature is 150-170°C, and the time is 1-3 seconds; the stretched BOPP film needs to be air-cooled immediately, and the cold air temperature is 10-20°C;

[0041] S4, after the transverse stretching process, it goes through the production processes such as online thickness measurement, edge material cutting, corona treatment, static elimination, automatic winding, aging treatment, etc.

[0042] S5. Cut the finished film rolls into corresponding specifications according to the customer's specific requirements.

[0043] The BOPP film produced according to the above raw material formula and production process has a total thickness of 33um, the upper surface layer 1 is 1.0um, the core layer 2 is 30um, and the lower surface layer 3 is 2.0um.

[0044] Example 2

[0045] The production process is basically the same as that of Example 1, except that the raw material formula is different. The BOPP cigarette wire-drawing base film that can be color-printed, gold-plated and laser-plated in this example is as follows:

[0046] The components of the upper surface layer 1 are calculated by weight: 95 parts by weight of copolymerized polypropylene and 5 parts by weight of anti-sticking masterbatch; the carrier of the anti-sticking masterbatch is copolymerized polypropylene, and the effective component of the anti-sticking masterbatch is silicon dioxide particles with a particle size of 4 um and a concentration of 5%.

[0047] The components of the core layer 2 are calculated by weight: 74 parts by weight of homopolymer polypropylene, 3 parts by weight of antistatic masterbatch, and 23 parts by weight of stiffening agent masterbatch;

[0048] The components of the lower surface layer 3 are calculated by weight: 95 parts by weight of copolymerized polypropylene and 5 parts by weight of anti-sticking masterbatch;

[0049] The color-printable, gold-plated and laser-coated BOPP cigarette cable base film prepared in Example 1 and Example 2 not only meets the basic requirements of cigarette cable, such as gold plating, printing and gluing, and machine runnability, which all meet customer standards. In addition, the function of laser molding is added to the lower surface layer 3 to meet the innovative requirements of customers. The color-printable, gold-plated and laser-coated BOPP cigarette cable base film is equivalent to introducing laser technology into the cable base material, increasing customer options and increasing the added value of the product.

[0050] In Example 1 and Example 2, the copolymerized polypropylene used for the upper surface layer 1 and the lower surface layer 3 is a pure heat-sealing material, and the amount used should also be processed differently. Because the requirements of laser molding must be taken into account, the thickness of the heat-sealing material of the lower surface layer 3 should be thickened to enhance the laser effect. The thickness of the lower surface layer 3 designed by the present invention is 2um, which has been doubled.

[0051] The anti-sticking masterbatch selected for the upper surface layer 1 and the lower surface layer 3 needs to take into account the transparency of the film. There are many types of anti-sticking masterbatch, and the effects on the haze and gloss of the film are also different. The refractive index of the anti-sticking particles selected in the present invention is very close to that of the BOPP film, and the surface is properly treated to maximize the optical properties of the substrate.

[0052] The antistatic masterbatch selected for the core layer 2 is preferably an amine material. Most antistatic masterbatches contain monoglycerides, which are beneficial for controlling static electricity, but once they migrate out, they will quickly eliminate the surface tension of the wire drawing base film, which is not conducive to subsequent processing. The migration speed of amine materials is relatively slow, and the surface tension retention is better. Of course, the present invention also achieves a reduced amount design for the addition amount.

[0053] The BOPP cigarette wire base film, which can be color-printed, gold-plated and laser-plated, has good opening properties and is very stable when used by downstream customers. Whether it is made into white (transparent) wire, gold wire, printed wire or laser wire, it can meet the requirements. During use in cigarette factories, indicators such as wire strength, elongation and shrinkage also reach a good level.

[0054] Comparative Example 1:

[0055] The same as Example 1, except that organic particles are added to the anti-sticking masterbatch of the upper and lower surface layers 3.

[0056] Comparative Example 2:

[0057] The same as Example 1, except that glass beads are added to the anti-sticking masterbatch of the upper and lower surface layers 3.

[0058] Comparative Example 3:

[0059] Same as Example 1, except that the particle size of the anti-sticking masterbatch of the lower surface layer 3 is 4 um.

[0060] Comparative Example 4:

[0061] The same as Example 1, except that the heat-sealing material of the upper and lower surface layers 3 is replaced with another brand of heat-sealing material with a melting point of 137° C. and containing a trace amount of a slippery additive.

[0062] Comparative Example 5:

[0063] The same as Example 1, except that monoglyceride is added to the antistatic masterbatch of the core layer 2.

[0064] Comparative Example 6:

[0065] Standard PE wire-drawing base film.

[0066] Comparative Example 7:

[0067] Standard PET wire-drawn base film.

[0068] The products of the embodiment and the comparative example were compared in terms of linear strength, shrinkage, haze, friction coefficient, surface tension maintenance, laser effect, and applicable scope. The data are as follows:

[0069]

[0070] The wire strengths of Example 1 and Example 2 are 5.6 N / mm and 5.7 N / mm respectively, showing better wire strengths than most comparative examples, which indicates that the materials and processes used in the present invention can provide sufficient mechanical strength to meet the needs of cigarette wires during use.

[0071] The shrinkage rates of Example 1 and Example 2 are 8.6% and 8.2%, which are at a relatively good level. Compared with Comparative Examples 1-7, they have better dimensional stability, which is beneficial to maintaining the close fit of the packaging.

[0072] The haze values ​​of Example 1 and Example 2 are 1.3% and 1.4% respectively, which show lower haze values ​​compared with Comparative Examples 1-7, which means that the wire-drawing base film has better transparency, which is beneficial to the aesthetics of the packaging.

[0073] The friction coefficients of Example 1 and Example 2 are 0.52 and 0.43 respectively, which are lower than those of Comparative Examples 1-7, and this helps to improve the processing performance of the packaging material, such as reducing machine blockage and bag rot when running on an automatic packaging line.

[0074] The surface tension maintenance of Examples 1 and 2 is excellent, which indicates that the developed wire drawing base film material can maintain good surface tension during processing and use, which is beneficial to subsequent processing such as printing, gold plating and gluing.

[0075] The laser effects of Example 1 and Example 2 are both excellent, and compared with the comparative example, they have better anti-counterfeiting properties, which is particularly important for the tobacco industry and can effectively prevent counterfeit and inferior products.

[0076] The applicable scopes of both Example 1 and Example 2 are wide, which means that they can be widely applied to different types of cigarette packaging and have wide market adaptability.

[0077] By comparing the tables, Example 1 and Example 2 are superior to Comparative Examples 1-7 in comprehensive performance, especially in terms of line strength, surface tension maintenance and laser molding effect. The present invention improves the performance of the wire drawing base film by optimizing materials and processes to meet the high standards and diversified needs of cigarette wire drawing. The newly developed wire drawing base film not only has good mechanical properties and processing properties, but also has excellent anti-counterfeiting properties, providing a more reliable choice for the tobacco packaging industry.

[0078] According to the experimental results in the above table, the present invention makes the BOPP wire drawing base film meet the requirements of downstream wire drawing enterprises in terms of wire strength, shrinkage, haze and friction coefficient through the balanced design and selection of various materials. In addition, the present invention also adds the function of laser molding to the wire drawing base material, and customers can choose according to their needs to achieve multifunctionality and high added value of the product.

[0079] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser, characterized in that: It is made of a three-layer structure of upper surface layer, core layer and lower surface layer, which are directly co-extruded and compounded; The components of the upper surface layer are calculated by weight: 95-98 parts by weight of copolymerized polypropylene and 2-5 parts by weight of anti-sticking masterbatch; The components of the core layer are calculated by weight: 71-79 parts by weight of homopolymer polypropylene, 1-4 parts by weight of antistatic masterbatch, and 20-25 parts by weight of rigidity-enhancing masterbatch; The components of the lower surface layer are calculated by weight: 95-98 parts by weight of copolymerized polypropylene and 2-5 parts by weight of anti-sticking masterbatch.

2. The BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to claim 1, characterized in that: The copolymer polypropylene used for the upper and lower surface layers is pure ternary copolymer polypropylene, the components are C2, C3, C4, and the melting point is 134°C. The copolymer polypropylene material does not contain trace amounts of lubricating or anti-sticking additives to ensure that the microscopic film surface is clean and smooth during laser molding.

3. The BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to claim 1 is characterized in that: The carrier of the anti-sticking masterbatch used in the upper surface layer is copolymerized polypropylene. The concentration of silicone oil-modified silica particles in the anti-sticking masterbatch is 5% and the particle size is 4 um.

4. The BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to claim 1 is characterized in that: The carrier of the anti-sticking masterbatch used in the lower surface layer is copolymerized polypropylene. The concentration of silicone oil-modified silica particles in the anti-sticking masterbatch is 5% and the particle size is 2 um.

5. The BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to claim 1 is characterized in that: The carrier of the antistatic masterbatch used in the core layer is homopolymer polypropylene, and the active ingredient of the antistatic masterbatch is ethoxylated amine with a concentration of 10%.

6. The BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to claim 1, characterized in that: The carrier of the stiffening masterbatch used in the core layer is homopolymer polypropylene, and the effective component of the stiffening masterbatch is DCPD-type hydrogenated petroleum resin with a concentration of 50%.

7. The BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing according to claim 1 is characterized in that: The total thickness of the BOPP cigarette wire-drawing base film is 33um, of which the upper surface layer is 1um thick, the core layer is 30um thick, and the lower surface layer is 2um thick.

8. A method for preparing a BOPP cigarette wire-drawing base film capable of color printing, gold plating and laser processing as claimed in any one of claims 1 to 7, characterized in that: The steps include: S1. The raw materials of the core layer are mixed evenly and dried, and then enter the melting single screw extruder and the metering single screw extruder in series for melting and plasticization, and then enter the die head through the filter. The temperature of each section is set to: 220-250℃, and the melt temperature is 210-270℃; S2, the raw materials of the upper surface layer and the lower surface layer are mixed evenly and dried, and then enter their respective single-screw extruders for melt plasticization, and then enter the die head through the filter. The temperature of each section is set to: 220-240℃, and the melt temperature is 220-250℃; S3, the three layers of polymer melt flow out after converging at the die head, and under the action of the air knife attachment device, adhere to the surface of the quench roller, and form a solid casting sheet after rapid cooling by the quench roller and the water tank, and then undergo longitudinal and transverse stretching in sequence; the longitudinal preheating temperature is 110-130℃, the stretching temperature is 80-100℃, the setting temperature is 80-100℃, and the longitudinal stretching ratio is 5.0-7.0; the transverse preheating temperature is 170-190℃, the stretching temperature is 140-160℃, the transverse stretching ratio is 8-10, the setting temperature is 150-170℃, and the time is 1-3 seconds; the stretched BOPP film needs to be air-cooled immediately, and the cold air temperature is 10-20℃; S4. After the transverse stretching process, it goes through the production processes such as online thickness measurement, edge material cutting, corona treatment, static elimination, automatic winding, aging treatment, etc. S5. Cut into finished films of corresponding specifications according to the customer's specific requirements.

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