Anti-yellowing and anti-adhesion BOPP (Biaxially-oriented Polypropylene) pre-coating film as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of BOPP (biaxially-oriented polypropylene) pre-coating films, and particularly relates to an anti-yellowing and anti-adhesion BOPP pre-coating film as well as a preparation method and application thereof. The anti-yellowing and anti-adhesion BOPP pre-coating film sequentially comprises a base material layer, a glue layer and a hot melt adhesive layer from outside to inside, the base material layer is a biaxially oriented polypropylene film; the glue layer is prepared from the following raw materials in percentage by mass: 0.1%-15% of glue, 0.1%-10% of a coupling agent, 50%-80% of water, 20%-50% of alcohol and 1%-5% of an antioxidant; the hot melt adhesive layer is prepared from the following raw materials in percentage by mass: 70%-95% of a hot melt adhesive main material and 5%-30% of a compatilizer. The anti-yellowing and anti-adhesion requirements of BOPP in the prior art are met, the technological operation is simple, and good industrial practicability is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of BOPP pre-coated films, and particularly relates to a BOPP pre-coated film with anti-yellowing and anti-sticking properties, a preparation method and an application thereof. Background Art

[0002] In today's era, with the rapid development of technology and the continuous progress of society, the packaging industry is constantly evolving, and the use of pre-coated films has become increasingly widespread. Pre-coated films, with their many advantages, add better protection and aesthetic effects to packaging products. However, traditional pre-coated films with primer have some troublesome problems. This is mainly due to the glue they use. On the one hand, over time or under specific environmental conditions, the glue is prone to chemical reactions, causing the pre-coated film to turn yellow, which greatly affects the overall aesthetics of the packaging. On the other hand, during the actual operation of film laminating, the sticky nature of the glue makes it easy to stick to the rollers, not only affecting the efficiency of film laminating but also resulting in uneven film laminating quality, bringing many troubles to packaging production. There is an urgent need to find effective solutions to improve these situations. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a BOPP pre-coated film with anti-yellowing and anti-sticking properties, a preparation method and an application thereof.

[0004] The object of the present invention can be achieved by the following technical solutions:

[0005] A BOPP pre-coated film with anti-yellowing and anti-sticking properties, the BOPP pre-coated film with anti-yellowing and anti-sticking properties sequentially comprises a base material layer, a glue layer and a hot melt adhesive layer from outside to inside;

[0006] The base material layer is a biaxially oriented polypropylene film;

[0007] The raw materials for preparing the glue layer include, by mass percentage: glue 0.1%-15%, coupling agent 0.1%-10%, water 50%-80%, alcohol 20%-50%, antioxidant 1%-5%;

[0008] The raw materials for preparing the hot melt adhesive layer include, by mass percentage: 70%-95% of the main hot melt adhesive, 5%-30% of the compatibilizer.

[0009] Further, the thickness of the base material layer is 10-20 μm, the thickness of the glue layer is 1-20 μm, and the thickness of the hot melt adhesive layer is 3-20 μm.

[0010] Further, the glue in the glue layer is selected from one or more of vinyl acetate polymers, polyurethanes, and epoxy resins; the coupling agent is selected from one or more of N-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; the antioxidant is selected from one or more of 2-tert-butyl-p-cresol and N,N'-diisopropyl-p-phenylenediamine.

[0011] Further, in the hot melt adhesive layer, the main components of the hot melt adhesive are one or more of ethylene-vinyl acetate polymers, polyolefin elastomers, and high-density polyethylene.

[0012] Further, the compatibilizer is one or more of C5 petroleum resin, polyethylene wax, and paraffin wax.

[0013] A method for preparing a yellowing-resistant and non-sticky BOPP pre-coated film, the preparation method comprising the following steps:

[0014] S1. Unwind the biaxially oriented polypropylene film to obtain a substrate layer, and perform pre-corona treatment on the surface of the substrate layer under high frequency and high voltage.

[0015] S2. Prepare a glue layer material by mixing glue, coupling agent, antioxidant, water, and alcohol according to the ratio in Claim 1, and coat the glue layer material on the surface of the corona-treated substrate layer to form a glue layer.

[0016] S3. Dry the glue layer using an oven, and then coat a hot melt adhesive layer material made of the main components of the hot melt adhesive and the compatibilizer on the surface of the anti-infrared layer by a casting method to form a hot melt adhesive layer; perform post-corona treatment on the surface of the hot melt adhesive layer under high frequency and high voltage, and then perform trimming, thickness measurement, and winding to obtain the yellowing-resistant and non-sticky BOPP pre-coated film.

[0017] Further, the preparation steps of the glue layer in step S2 are as follows: First, mix alcohol and water, then add the coupling agent, stir at room temperature for 3 h, then add the glue and stir at room temperature for 2 h, and finally add the antioxidant and stir for 90 min to obtain the glue layer material.

[0018] Further, the preparation steps of the hot melt adhesive layer material in step S3 are as follows: Stir the main components of the hot melt adhesive and the compatibilizer in a mixer for 60 min to obtain the hot melt adhesive layer material.

[0019] Further, the power of the high-frequency and high-voltage corona treatment in step S1 is 2 - 10 W / m 2 ; the power of the high-frequency and high-voltage corona treatment in step S3 is 5 - 15 W / m 2 .

[0020] The application of the above-mentioned yellowing-resistant and non-sticky BOPP pre-coated film in the fields of packaging boxes and product labels.

[0021] Advantages of the present invention: The present invention solves the requirements of anti-yellowing and adhesion in the prior art for BOPP, and can effectively maintain no yellowing after laminating, and no roller sticking during laminating. The process operation is simple and has good industrial practicability. Specific embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] In the following embodiments, the bottom-coatless biaxially oriented polypropylene film in the substrate layer is a BOPP bright type bottom-coatless base film. The BOPP bright type bottom-coatless base film is mainly used in the field of pre-coated laminating, and plays a role in protecting and decorating printed products. This product does not require coating a primer, and can be thermally pressed and compounded with paper after extrusion coating with EVA, and has excellent laminating strength. It is subjected to single-sided treatment (non-laminating side), and the conventional thicknesses are 12um and 15um

[0024] Example 1

[0025] An anti-yellowing and anti-adhesion BOPP pre-coated film, which sequentially includes a substrate layer, an adhesive layer, and a hot melt adhesive layer from outside to inside. The material of the substrate layer is a biaxially oriented polypropylene film; the raw materials for preparing the adhesive layer include 5% by mass of vinyl acetate, 2% of N-aminoethyl-γ-aminopropyltrimethoxysilane, 1% of 2-tert-butyl-p-cresol, 60% of water, and 32% of alcohol. The raw materials for preparing the hot melt adhesive layer include 85% of ethylene-vinyl acetate, 10% of C5 petroleum resin, and 5% of paraffin by mass.

[0026] The preparation method specifically includes the following steps:

[0027] S1. Unwind a 12μm thick biaxially oriented polypropylene film to obtain the substrate layer, and perform pre-corona treatment on the surface of the substrate layer with high frequency and high voltage; the corona power is 7kW;

[0028] S2. Prepare the adhesive layer material from the adhesive, coupling agent, antioxidant, water, and alcohol, and coat it on the surface of the corona-treated substrate layer to form an adhesive layer; the thickness is 2μm;

[0029] S3. Use an oven to dry the glue layer by layer, and then coat the surface of the anti-infrared layer with a hot melt adhesive layer material made of ethylene-vinyl acetate, compatibilizer, and paraffin wax by the casting method to form a hot melt adhesive layer; the thickness is 10 μm; corona treatment is performed on the surface of the hot melt adhesive layer under high frequency and high voltage, and the corona power is 10 KW. After trimming, thickness measurement, and winding, a BOPP pre-coated film with anti-yellowing and anti-adhesion properties can be obtained.

[0030] Comparative Example 1

[0031] A common BOPP pre-coated film includes a base material layer, a glue layer, and a hot melt adhesive layer from outside to inside in sequence. The base material layer is made of a biaxially oriented polypropylene film; the raw materials for preparing the glue layer include 80% water, 17% alcohol, and 3% glue polyvinylimine by mass percentage. The raw material for preparing the hot melt adhesive layer is ethylene-vinyl acetate. The preparation method specifically includes the following steps:

[0032] S1. Unroll a 12-μm-thick biaxially oriented polypropylene film to obtain the base material layer, and perform corona treatment on the surface of the base material layer before high frequency and high voltage; the corona power is 7 kW;

[0033] S2. Make a glue layer material from polyvinylimine raw glue, water, and alcohol and coat it on the surface of the corona-treated base material layer to form a glue layer; the thickness is 2 μm;

[0034] S3. Use an oven to dry the glue layer by layer, and then coat the surface of the glue layer with ethylene-vinyl acetate by the casting method to form a hot melt adhesive layer; the thickness is 10 μm; corona treatment is performed on the surface of the hot melt adhesive layer under high frequency and high voltage, and the corona power is 10 KW. After trimming, thickness measurement, and winding, a BOPP pre-coated film with anti-yellowing and anti-adhesion properties can be obtained.

[0035] Place the BOPP pre-coated films prepared in Example 1 and Comparative Example 1 in a thermostatic and humidistatic test chamber, set the temperature to 80 °C, the relative humidity to 85%, and the test time to 500 hours.

[0036] After placing for 60 days, use a colorimeter for testing, and the results are shown in the following table:

[0037] Temperature L a b Example 1 88.22 -0.40 2.95 Comparative Example 1 87.76 -0.35 4.65

[0038] From the numerical comparison and analysis of Example 1 and Comparative Example 1 in the above table, it can be seen that for the anti-yellowing and anti-adhesion BOPP pre-coated film prepared in the invention example 1, after being placed for a period of time, the b value of the colorimetric test is significantly smaller than that of Comparative Example 1, indicating that the anti-yellowing and anti-adhesion BOPP pre-coated film has certain anti-yellowing performance.

[0039] Take two 10 cm × 10 cm BOPP pre-coated film samples prepared in Example 1 and Comparative Example 1, laminate them face to face, place a 1 kg weight on them for pressing, and put them into a thermostatic and humidistatic test chamber. Set the temperature to 60 °C and the relative humidity to 85%, take out the samples after maintaining for 24 hours, and conduct peel strength tests. The results are shown in the following table.

[0040] Peel Strength 1 Peel Strength 1 Peel Strength 1 Example 1 0.01 0.02 0.01 Comparative Example 1 0.05 0.04 0.04 Testing Method GB / T8808 GB / T8808 GB / T8808

[0041] It can be seen from the numerical comparison and analysis of Example 1 and Comparative Example 1 in the above table that after the anti-yellowing and anti-adhesion BOPP pre-coated film sample prepared in the invention is placed for a period of time, the peel strength is significantly smaller, indicating that the anti-yellowing and anti-adhesion BOPP pre-coated film has certain anti-adhesion performance.

[0042] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0043] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A BOPP pre-coated film with resistance to yellowing and adhesion, characterized in that: The anti-yellowing and anti-adhesive BOPP pre-coated film comprises a substrate layer, a glue layer and a hot melt adhesive layer from the outside to the inside; The substrate layer is a biaxially oriented polypropylene film; The raw materials for preparing the glue layer include, by mass percentage: 0.1%-15% glue, 0.1%-10% coupling agent, 50%-80% water, 20%-50% alcohol, and 1%-5% antioxidant; The raw materials for preparing the hot melt adhesive layer include, by mass percentage: 70%-95% of hot melt adhesive main material and 5%-30% of compatibilizer.

2. The anti-yellowing and anti-adhesion BOPP pre-coated film according to claim 1, characterized in that: The thickness of the substrate layer is 10-20 μm, the thickness of the glue layer is 1-20 μm, and the thickness of the anti-infrared layer and the hot-melt adhesive layer is 3-20 μm.

3. The anti-yellowing and anti-adhesion BOPP pre-coated film according to claim 1, characterized in that: The glue in the glue layer is selected from one or more of vinyl acetate polymer, polyurethane, and epoxy resin; the coupling agent is selected from one or more of N-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; and the antioxidant is selected from one or more of 2-tert-butyl-p-cresol and N,N'-diisopropyl-p-phenylenediamine.

4. The anti-yellowing and anti-adhesion BOPP pre-coated film according to claim 1, characterized in that: In the hot melt adhesive layer, the main ingredient of the hot melt adhesive is one or more of ethylene-vinyl acetate polymer, polyolefin elastomer, and high-density polyethylene.

5. The anti-yellowing and anti-adhesion BOPP pre-coated film according to claim 1, characterized in that: The compatibilizer is one or more of C5 petroleum resin, polyethylene wax and paraffin.

6. A method for preparing a BOPP pre-coated film that resists yellowing and adhesion, characterized in that: The preparation method comprises the following steps: S1, unwinding a biaxially oriented polypropylene film to obtain a substrate layer, and performing a high-frequency and high-voltage pre-corona treatment on the surface of the substrate layer; S2. According to the ratio of claim 1, glue, coupling agent, antioxidant, water and alcohol are prepared into a glue layer material and coated on the surface of the corona treated substrate layer to form a glue layer; S3. Use an oven to dry the glue layer, and then use a casting method to coat the hot melt adhesive layer material made of the hot melt adhesive main ingredient and the compatibilizer on the surface of the anti-infrared layer to form a hot melt adhesive layer; perform high-frequency and high-voltage post-corona treatment on the surface of the hot melt adhesive layer, and then trim, measure thickness, and roll up to obtain a yellowing-resistant and adhesion-resistant BOPP pre-coated film.

7. The method for preparing a yellowing-resistant and blocking-resistant BOPP pre-coating film according to claim 6, characterized in that: The preparation steps of the glue layer in step S2 are: first mix alcohol and water, then add a coupling agent, stir at room temperature for 3 hours, then add glue and stir at room temperature for 2 hours, and finally add an antioxidant and stir for 90 minutes to obtain the glue layer material.

8. The method for preparing a yellowing-resistant and blocking-resistant BOPP pre-coated film according to claim 6, characterized in that: The preparation step of the hot melt adhesive layer material in step S3 is: stir the hot melt adhesive main material and the compatibilizer in a mixer for 60 minutes to obtain the hot melt adhesive layer material.

9. The method for preparing a yellowing-resistant and blocking-resistant BOPP pre-coating film according to claim 6, characterized in that: The power of high frequency and high voltage corona treatment in step S1 is 2-10W / m 2 ; The power of high frequency high voltage corona treatment in step S3 is 5-15W / m 2 .

10. Use of the yellowing-resistant and blocking-resistant BOPP pre-coated film according to any one of claims 1 to 5 in the field of packaging boxes and product labels.