Composite layer and application thereof in CPP film and packaging material

Abstract

The invention discloses a composite layer and application thereof in a CPP film and a packaging material, and first raw materials for forming the composite layer comprise, by mass, 30-80% of first polypropylene random copolymer and 10-50% of first polypropylene recycled particles. The composite layer is used for preparing the CPP film, and the prepared CPP film is high in corona value and good in corona maintaining effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of packaging materials, and particularly relates to a composite layer and application thereof in CPP film and packaging materials. BACKGROUND

[0002] The cast polypropylene film (CPP) is a kind of flat extrusion film produced by melt casting quenching without stretching and orientation, which has the characteristics of easy heat sealing, good toughness, high transparency, etc., and is widely used in food and daily chemical CPP films. The CPP film is generally composed of a heat sealing layer, a core layer and a composite layer.

[0003] In the preparation process of the CPP film, the composite layer of the CPP film is used as a material for compounding with aluminum foil, nylon, PET and other films, and the corona performance of the composite layer has a great influence on the compounding performance of the CPP film. However, the CPP film belongs to a non-polar material, and the surface tension is relatively low, generally about 30-32 dynes, in order to improve the surface tension of the CPP film and enhance its adhesion performance with ink, glue or other materials, corona treatment is needed, but even after corona treatment, the CPP film will quickly decrease to below 36 dynes after 3 months, and for those skilled in the art, it is very difficult to increase the dynes value of the CPP film by 1-2 dynes. Especially when polypropylene recycled particles are added to the material for preparing the composite layer, the corona value of the composite layer will decrease due to the multiple processing and melting of the recycled particles and the precipitation of additives, and the corona retention effect is even worse. Therefore, how to use the environmentally friendly material polypropylene recycled particles to prepare the composite layer while ensuring that the corona performance of the CPP film is not affected is a problem to be solved. SUMMARY

[0004] In view of the deficiencies of the prior art, the composite layer of the present application is used to prepare a CPP film, and the obtained CPP film has a high corona value and good corona retention effect.

[0005] The purpose of the present application is to provide a composite layer, the first raw material for forming the composite layer includes 30-80% of first random copolymerized polypropylene and 10-50% of first polypropylene recycled particles, the first random copolymerized polypropylene is a propylene-ethylene random copolymer, and the melting point is 140-150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 1.5-11 g / 10min, and the density is 0.89-0.91 g / cm 3 ; the melting point of the first polypropylene recycled particles is 140-165℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 3-9 g / 10min, and the density is 0.89-0.91 g / cm 3 .

[0006] In some embodiments of the present application, the first random copolymerized polypropylene has a melt mass flow rate of 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min or 10 g / 10 min at 230℃ / 2.16kg.

[0007] In some embodiments of the present application, the first raw material further comprises 0-30% of a first homopolymerized polypropylene and 0-30% of a first impact polypropylene, or 0.01-30% of a first homopolymerized polypropylene and 0.01-30% of a first impact polypropylene, the first homopolymerized polypropylene has a melting point of 160-170℃, a melt mass flow rate of 3-8 g / 10 min at 230℃ / 2.16kg, and a density of 0.89-0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150-165℃, a melt mass flow rate of 2-6 g / 10 min at 230℃ / 2.16kg, and a density of 0.89-0.91 g / cm 3 .

[0008] In some embodiments of the present application, the first raw material further comprises 5-20% of a first homopolymerized polypropylene and 5-20% of a first impact polypropylene.

[0009] In some embodiments of the present application, the first raw material further comprises 0-5% of silicon dioxide.

[0010] In some embodiments of the present application, the first raw material further comprises 1-5% of silicon dioxide.

[0011] Another object of the present application is to provide a CPP film, which comprises a heat-seal layer, a core layer and the composite layer arranged in sequence.

[0012] In some embodiments of the present application, the second raw material for forming the heat-seal layer comprises, in terms of mass percentage, 30-80% of a second random copolymerized polypropylene, 0-20% of a second homopolymerized polypropylene and 0-50% of a second impact polypropylene, the second random copolymerized polypropylene is a propylene-ethylene random copolymer, and has a melting point of 140-150℃, a melt mass flow rate of 1.5-11 g / 10 min at 230℃ / 2.16kg, and a density of 0.89-0.91 g / cm 3 ; the second homopolymerized polypropylene has a melting point of 160-170℃, a melt mass flow rate of 3-8 g / 10 min at 230℃ / 2.16kg, and a density of 0.89-0.91 g / cm 3; the second impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150-165 DEG C, a melt mass flow rate of 2-6 g / 10 min under the condition of 230 DEG C / 2.16 kg, and a density of 0.89-0.91 g / cm 3 .

[0013] In some embodiments of the present application, the second raw material forming the heat-seal layer comprises, in mass percentage: 30-80% of the second random copolymerized polypropylene, 5-15% of the second homopolymerized polypropylene, and 10-50% of the second impact polypropylene.

[0014] In some embodiments of the present application, the second raw material further comprises 1-5% of silica and 1-5% of erucamide type slip agent.

[0015] In some embodiments of the present application, the third raw material forming the core layer comprises, in mass percentage: 0-80% or 0.01-80% of the third polypropylene recycled particles, 15-70% of the third random copolymerized polypropylene, and 0-20% or 0.01-20% of the polyolefin elastomer, the third polypropylene recycled particles having a melting point of 140-165 DEG C, a melt mass flow rate of 3-9 g / 10 min under the condition of 230 DEG C / 2.16 kg, and a density of 0.89-0.91 g / cm 3 ; the third random copolymerized polypropylene is a random copolymer of propylene and ethylene, and has a melting point of 140-150 DEG C, a melt mass flow rate of 1.5-11 g / 10 min under the condition of 230 DEG C / 2.16 kg, and a density of 0.89-0.91 g / cm 3 ; the polyolefin elastomer is a copolymer of propylene and ethylene, the polyolefin elastomer having a Vicat softening point temperature of 45-110 DEG C, a melt mass flow rate of 1-9 g / 10 min under the condition of 190 DEG C / 2.16 kg, and a density of 0.86-0.90 g / cm 3 .

[0016] In some embodiments of the present application, the third raw material forming the core layer comprises, in mass percentage: 30-80% of the third polypropylene recycled particles.

[0017] In some embodiments of the present application, the third raw material forming the core layer comprises, in mass percentage: 5-20% of the polyolefin elastomer.

[0018] In some embodiments of the present application, the third raw material forming the core layer comprises, in mass percentage: 30-55% of the third polypropylene recycled particles, 15-40% of the third random copolymerized polypropylene, and 5-15% of the polyolefin elastomer.

[0019] In some embodiments of the present application, the third raw material further comprises 0-20% of a third homopolymer polypropylene, the third homopolymer polypropylene has a melting point of 160-170℃, a melt mass flow rate of 3-8 g / 10 min under the condition of 230℃ / 2.16 kg, and a density of 0.89-0.91 g / cm3.

[0020] In some embodiments of the present application, the third raw material further comprises 5-15% of a third homopolymer polypropylene.

[0021] In some embodiments of the present application, the third raw material further comprises 0-30% of a third impact polypropylene, the third impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150-165℃, a melt mass flow rate of 2-6 g / 10 min under the condition of 230℃ / 2.16 kg, and a density of 0.89-0.91 g / cm3.

[0022] In some embodiments of the present application, the third raw material further comprises 10-25% of a third impact polypropylene.

[0023] In some embodiments of the present application, the thickness percentage of the heat-seal layer, the core layer and the composite layer in the CPP film is 10-25%: 50-80%: 10-25%, specifically, the thickness percentage of the heat-seal layer, the core layer and the composite layer includes but is not limited to 10%: 80%: 10%, 15%: 70%: 15%, 20%: 60%: 20%, 25%: 50%: 25%.

[0024] In some embodiments of the present application, the thickness of the CPP film is 25-120 um.

[0025] Another object of the present application is to provide a preparation method of the CPP film, which forms the heat-seal layer, the core layer and the composite layer arranged in sequence by using a multi-layer co-extrusion casting method.

[0026] Another object of the present application is to provide a packaging material prepared from the CPP film.

[0027] In some embodiments of the present application, the packaging material comprises a PET layer, a nylon layer, an aluminum foil layer and a CPP film, and the nylon layer, the aluminum foil layer and the CPP film are arranged in sequence on the PET layer.

[0028] In some embodiments of the present application, the packaging material comprises a PET layer, an aluminum foil layer, a nylon layer and a CPP film, and the aluminum foil layer, the nylon layer and the CPP film are arranged in sequence on the PET layer.

[0029] In some embodiments of the application, the packaging material comprises a PET layer, an aluminum foil layer and a CPP film, the aluminum foil layer being arranged between the PET layer and the CPP film.

[0030] In some embodiments of the application, the packaging material comprises a nylon layer, an aluminum foil layer and a CPP film, the aluminum foil layer being arranged between the nylon layer and the CPP film.

[0031] In some embodiments of the application, the packaging material comprises a BOPP film, an aluminum foil layer and a CPP film, the aluminum foil layer being arranged between the BOPP film and the CPP film.

[0032] In some embodiments of the application, the packaging material comprises a PET layer, a nylon layer and a CPP film, the nylon layer being arranged between the PET layer and the CPP film.

[0033] In some embodiments of the application, the packaging material comprises a nylon layer, a PET layer and a CPP film, the PET layer being arranged between the nylon layer and the CPP film.

[0034] In some embodiments of the application, the packaging material comprises a BOPP film, a nylon layer and a CPP film, the nylon layer being arranged between the BOPP film and the CPP film.

[0035] In some embodiments of the application, the packaging material comprises a PET layer, a PET layer and a CPP film, the PET layer being arranged between the PET layer and the CPP film.

[0036] In some embodiments of the application, the packaging material comprises a nylon layer, a nylon layer and a CPP film, the nylon layer being arranged between the nylon layer and the CPP film.

[0037] In some embodiments of the application, the packaging material comprises a PET layer and a CPP film, the CPP film being arranged on the PET layer.

[0038] In some embodiments of the application, the packaging material comprises a nylon layer and a CPP film, the CPP film being arranged on the nylon layer.

[0039] In some embodiments of the application, the packaging material comprises a BOPP film, a BOPP film and a CPP film, the BOPP film being arranged between the BOPP film and the CPP film.

[0040] In some embodiments of the application, the packaging material comprises a BOPP film and a CPP film, the CPP film being arranged on the BOPP film.

[0041] In some embodiments of the present application, the packaging material comprises a BOPP film, a MCPP film and a CPP film, the MCPP film is sequentially laminated on the BOPP film, and the CPP film is sequentially laminated on the MCPP film.

[0042] In some embodiments of the present application, the packaging material comprises two layers of CPP films.

[0043] In some embodiments of the present application, the packaging material is a CPP film. DETAILED DESCRIPTION

[0044] In order to enable persons skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative labor should fall within the protection scope of the present application.

[0045] The raw materials used in the present application are all conventional commercially available.

[0046] Embodiment 1

[0047] The present embodiment provides a CPP film, and the specific process is as follows:

[0048] The raw materials for forming the heat-sealing layer are, in mass percentage: 80% of the second random copolymerized polypropylene, 5% of the second homopolymerized polypropylene, 10% of the second impact polypropylene, 2% of the silicon dioxide, and 3% of the erucamide type slip agent. The second random copolymerized polypropylene is a propylene-ethylene random copolymer, and has a melting point of 150℃, a melt mass flow rate of 1.5 g / 10 min under the condition of 230℃ / 2.16 kg, and a density of 0.89 g / cm 3 ; the second homopolymerized polypropylene has a melting point of 165℃, a melt mass flow rate of 6 g / 10 min under the condition of 230℃ / 2.16 kg, and a density of 0.91 g / cm 3 ; and the second impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150℃, a melt mass flow rate of 6 g / 10 min under the condition of 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 ;

[0049] The raw materials for forming the core layer are: 40% of a third random copolymerized polypropylene, 15% of a third homopolymerized polypropylene, 10% of a third impact polypropylene, 5% of a polyolefin elastomer, and 30% of third polypropylene recycled particles, the third random copolymerized polypropylene is a propylene, ethylene random copolymer, and the melting point is 142℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8 g / 10min, the density is 0.90 g / cm 3 ; the melting point of the third homopolymerized polypropylene is 161℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 7.5 g / 10min, the density is 0.91 g / cm 3 ; the third impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6 g / 10min, the density is 0.90 g / cm 3 ; the polyolefin elastomer is a copolymer of propylene and ethylene, the Vicat softening point of the polyolefin elastomer is 101℃, the melt mass flow rate under the condition of 190℃ / 2.16kg is 3 g / 10min, the density is 0.86 g / cm 3 ; the melting point of the third polypropylene recycled particles is 145℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8.5 g / 10min, the density is 0.90 g / cm 3 ;

[0050] The raw materials for forming the composite layer are: 79% of a first random copolymerized polypropylene, 5% of a first homopolymerized polypropylene, 5% of a first impact polypropylene, 10% of first polypropylene recycled particles, and 1% of silicon dioxide, the first random copolymerized polypropylene is a propylene, ethylene random copolymer, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 1.5 g / 10min, the density is 0.89 g / cm 3 ; the melting point of the first homopolymerized polypropylene is 161℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 7.5 g / 10min, the density is 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6 g / 10min, the density is 0.90 g / cm 3 ; the melting point of the first polypropylene recycled particles is 145℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8.5 g / 10min, the density is 0.90 g / cm 3 ;

[0051] The raw materials of the heat-sealing layer, the core layer and the composite layer are respectively fed into three extruders of a three-layer co-extrusion casting machine according to the above required proportions by mass percentage, the thickness percentage of the three layers is set to 15%:70%:15%, the temperature of the extrusion of the die is 230±10℃, the chilling roller used is a smooth roller, the temperature of which is 22±3℃, the speed of the production line is set to 100±10m / min, the power of the corona is set to 12kW, and the initial tension of the winding is set to 12KG, so as to obtain a 70μm CPP film.

[0052] Example 2

[0053] The present embodiment provides a CPP film, and the specific process is as follows:

[0054] The raw materials for forming the heat-sealing layer are, by mass percentage: 30% of second random copolymerized polypropylene, 10% of second homopolymerized polypropylene, 50% of second impact polypropylene, 5% of silicon dioxide and 5% of erucamide type slip agent, the second random copolymerized polypropylene is a propylene-ethylene random copolymer, the melting point of which is 142℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8 g / 10min, and the density is 0.90 g / cm 3 ; the melting point of the second homopolymerized polypropylene is 169℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 3.5 g / 10min, and the density is 0.91 g / cm 3 ; the second impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, the melting point of which is 154℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 5 g / 10min, and the density is 0.9 g / cm 3 ;

[0055] The raw materials for forming the core layer are: 25% of third random copolymerized polypropylene, 5% of third homopolymerized polypropylene, 10% of third impact polypropylene, 5% of polyolefin elastomer and 55% of third polypropylene recycled particles, the third random copolymerized polypropylene is a propylene-ethylene random copolymer, the melting point of which is 144℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 5.5 g / 10min, and the density is 0.90 g / cm 3 ; the melting point of the third homopolymerized polypropylene is 165℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6 g / 10min, and the density is 0.91 g / cm 3 ; the third impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, the melting point of which is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6 g / 10min, and the density is 0.9 g / cm 3; the polyolefin elastomer is a copolymer of propylene, ethylene, the Vicat softening point of the polyolefin elastomer is 85℃, the melt mass flow rate under the condition of 190℃ / 2.16kg is 4 g / 10 min, and the density is 0.89 g / cm 3 ; the melting point of the third polypropylene recycled particles is 152℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6 g / 10 min, and the density is 0.91 g / cm 3 ;

[0056] The raw materials for forming the composite layer are: 30% of first random copolymerized polypropylene, 8% of first homopolymerized polypropylene, 7% of first impact polypropylene, 50% of first polypropylene recycled particles, and 5% of silicon dioxide, the first random copolymerized polypropylene is a random copolymer of propylene and ethylene, and the melting point is 144℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 5.5 g / 10 min, and the density is 0.9 g / cm 3 ; the melting point of the first homopolymerized polypropylene is 161℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 7.5 g / 10 min, and the density is 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and the melting point is 162℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 2 g / 10 min, and the density is 0.9 g / cm 3 ; the melting point of the first polypropylene recycled particles is 145℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8.5 g / 10 min, and the density is 0.9 g / cm 3 ;

[0057] The raw materials of the heat-sealing layer, the core layer and the composite layer are respectively high-temperature melted according to the above required proportions by mass percentage, and are respectively put into three extruders corresponding to the three-layer co-extrusion flow machine, the thickness percentage of the three layers is set to 10%:80%:10%, the temperature of the die extrusion is 230±10℃, the chilling roller used is a smooth roller, the temperature of which is 22±3℃, the speed of the production line is set to 120±10 m / min, the corona power is set to 11 kW, and the initial winding tension is set to 10 KG, so as to obtain a 50μm CPP film.

[0058] Example 3

[0059] The present embodiment provides a CPP film, and the specific process is as follows:

[0060] The raw materials for forming the heat-seal layer are, in mass percentage: 50% of a second random copolymerized polypropylene, 20% of a second homopolymerized polypropylene, 28% of a second impact polypropylene, 1% of silicon dioxide, and 1% of a erucamide type slip agent; the second random copolymerized polypropylene is a propylene-ethylene random copolymer, has a melting point of 150°C, a melt mass flow rate of 3.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the second homopolymerized polypropylene has a melting point of 166°C, a melt mass flow rate of 4 g / 10 min at 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ; the second impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, has a melting point of 160°C, a melt mass flow rate of 3 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 ;

[0061] The raw materials for forming the core layer are: 15% of a third random copolymerized polypropylene, 15% of a third homopolymerized polypropylene, 25% of a third impact polypropylene, 15% of a polyolefin elastomer, and 30% of third polypropylene recycled particles; the third random copolymerized polypropylene is a propylene-ethylene random copolymer, has a melting point of 150°C, a melt mass flow rate of 1.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the third homopolymerized polypropylene has a melting point of 169°C, a melt mass flow rate of 3.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ; the third impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, has a melting point of 162°C, a melt mass flow rate of 2 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 ; the polyolefin elastomer is a copolymer of propylene and ethylene, has a Vicat softening point of 63°C, a melt mass flow rate of 5 g / 10 min at 190°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the third polypropylene recycled particles have a melting point of 162°C, a melt mass flow rate of 3.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ;

[0062] The raw materials for forming the composite layer are: 40% of first random copolymerized polypropylene, 20% of first homopolymerized polypropylene, 20% of first impact polypropylene, 18% of first polypropylene recycled particles, and 2% of silicon dioxide, the first random copolymerized polypropylene is a propylene-ethylene random copolymer, and the melting point is 142℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8 g / 10min, and the density is 0.90 g / cm 3 ; the melting point of the first homopolymerized polypropylene is 169℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 3.5 g / 10min, and the density is 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and the melting point is 154℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 5 g / 10min, and the density is 0.9 g / cm 3 ; the melting point of the first polypropylene recycled particles is 162℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 3.5 g / 10min, and the density is 0.91 g / cm 3 ;

[0063] According to the mass percentage, the raw materials of the heat-sealing layer, the core layer and the composite layer are respectively high-temperature melted in the screw according to the above required proportion, and are respectively put into three extruders corresponding to the three-layer co-extrusion flow machine, the thickness percentage of the three layers is set to 20%:60%:20%, the temperature of the die extrusion is 230±10℃, the chilling roller used is a smooth roller, the temperature of which is 22±3℃, the speed of the production line is set to 80±10m / min, the corona power is set to 14 kW, and the initial winding tension is set to 13KG, so as to obtain a 90μm CPP film.

[0064] Example 4

[0065] The present embodiment provides a CPP film, and the specific process is as follows:

[0066] The difference between the present embodiment and Example 1 is that the raw materials for forming the composite layer are different, and the present embodiment does not contain the first homopolymerized polypropylene, and the other aspects are the same as those of Example 1; according to the mass percentage, the raw materials for forming the composite layer of the present embodiment are: 79% of first random copolymerized polypropylene, 5% of first impact polypropylene, 15% of first polypropylene recycled particles, and 1% of silicon dioxide, the first random copolymerized polypropylene is a propylene-ethylene random copolymer, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 1.5 g / 10min, and the density is 0.89 g / cm 3; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150°C, a melt mass flow rate of 6 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 ; the first polypropylene recycled particle has a melting point of 145°C, a melt mass flow rate of 8.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 .

[0067] Example 5

[0068] This example provides a CPP film, and the specific process is as follows:

[0069] The difference between this example and Example 1 is that the raw materials for forming the composite layer are different, and this example does not contain the first impact polypropylene, and the others are the same as Example 1; the raw materials for forming the composite layer in this example are, by mass percentage: 79% of the first random copolymer polypropylene, 5% of the first homopolymer polypropylene, 15% of the first polypropylene recycled particle, and 1% of the silicon dioxide; the first random copolymer polypropylene is a propylene-ethylene random copolymer, and has a melting point of 150°C, a melt mass flow rate of 1.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the first homopolymer polypropylene has a melting point of 161°C, a melt mass flow rate of 7.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ; the first polypropylene recycled particle has a melting point of 145°C, a melt mass flow rate of 8.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 .

[0070] Example 6

[0071] This example provides a CPP film, and the specific process is as follows:

[0072] The difference between this example and Example 1 is that the raw materials for forming the composite layer are different, and the structure of the first homopolymer polypropylene in this example is different from that in Example 1, and the others are the same as Example 1; the raw materials for forming the composite layer in this example are, by mass percentage: 79% of the first random copolymer polypropylene, 5% of the first homopolymer polypropylene, 5% of the first impact polypropylene, 10% of the first polypropylene recycled particle, and 1% of the silicon dioxide; the first random copolymer polypropylene is a propylene-ethylene random copolymer, and has a melting point of 150°C, a melt mass flow rate of 1.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.89 g / cm 3; the first homopolymer polypropylene has a melting point of 165°C, a melt mass flow rate of 6 g / 10 min at 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150°C, a melt mass flow rate of 6 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 ; the first polypropylene recycled particle has a melting point of 145°C, a melt mass flow rate of 8.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 .

[0073] Example 7

[0074] This example provides a CPP film, and the specific process is as follows:

[0075] The difference between this example and Example 1 is that the raw materials for forming the composite layer are different, and the structure of the first impact polypropylene in this example is different from that in Example 1, and the others are the same as in Example 1; the raw materials for forming the composite layer in this example are, in mass percentage: 79% of the first random copolymer polypropylene, 5% of the first homopolymer polypropylene, 5% of the first impact polypropylene, 10% of the first polypropylene recycled particle, and 1% of the silicon dioxide; the first random copolymer polypropylene is a propylene-ethylene random copolymer, and has a melting point of 150°C, a melt mass flow rate of 1.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the first homopolymer polypropylene has a melting point of 165°C, a melt mass flow rate of 6 g / 10 min at 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150°C, a melt mass flow rate of 6 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 ; the first polypropylene recycled particle has a melting point of 145°C, a melt mass flow rate of 8.5 g / 10 min at 230°C / 2.16 kg, and a density of 0.90 g / cm 3 .

[0076] Example 8

[0077] This example provides a CPP film, and the specific process is as follows:

[0078] The difference between this embodiment and Example 1 is that the raw material for forming the composite layer is different, this embodiment does not contain silica, and the others are the same as Example 1; the raw material for forming the composite layer in this embodiment is, in mass percentage: 79% of first random copolymerized polypropylene, 5% of first homopolymerized polypropylene, 6% of first impact polypropylene, and 10% of first polypropylene recycled particles; the first random copolymerized polypropylene is a propylene-ethylene random copolymer, and has a melting point of 150°C, a melt mass flow rate of 1.5 g / 10 min under the condition of 230°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the first homopolymerized polypropylene has a melting point of 161°C, a melt mass flow rate of 7.5 g / 10 min under the condition of 230°C / 2.16 kg, and a density of 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150°C, a melt mass flow rate of 6 g / 10 min under the condition of 230°C / 2.16 kg, and a density of 0.90 g / cm 3 ; and the first polypropylene recycled particles have a melting point of 145°C, a melt mass flow rate of 8.5 g / 10 min under the condition of 230°C / 2.16 kg, and a density of 0.90 g / cm 3 .

[0079] Example 9

[0080] This embodiment provides a CPP film, and the specific process is as follows:

[0081] The difference between this embodiment and Example 1 is that the raw material for forming the heat-sealing layer is different, this embodiment does not contain second homopolymerized polypropylene, and the others are the same as Example 1; the raw material for forming the heat-sealing layer in this embodiment is, in mass percentage: 80% of second random copolymerized polypropylene, 15% of second impact polypropylene, 2% of silica, and 3% of erucamide type slip agent; the second random copolymerized polypropylene is a propylene-ethylene random copolymer, and has a melting point of 150°C, a melt mass flow rate of 1.5 g / 10 min under the condition of 230°C / 2.16 kg, and a density of 0.89 g / cm 3 ; the second impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150°C, a melt mass flow rate of 6 g / 10 min under the condition of 230°C / 2.16 kg, and a density of 0.90 g / cm 3 .

[0082] Example 10

[0083] This embodiment provides a CPP film, and the specific process is as follows:

[0084] The difference between this embodiment and example 1 is that the raw material for forming the heat-seal layer is different, this embodiment does not contain the second impact polypropylene, and the other is the same as example 1; the raw material for forming the heat-seal layer in this embodiment is 80% of the second random copolymerized polypropylene, 15% of the second homopolymerized polypropylene, 2% of the silicon dioxide and 3% of the erucic acid amide type slip agent in terms of mass percentage, the second random copolymerized polypropylene is the random copolymer of propylene and ethylene, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 1.5g / 10min, and the density is 0.89g / cm 3 ; the melting point of the second homopolymerized polypropylene is 165℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6g / 10min, and the density is 0.91g / cm 3 .

[0085] Example 11

[0086] This embodiment provides a CPP film, and the specific process is as follows:

[0087] The difference between this embodiment and example 1 is that the raw material for forming the core layer is different, this embodiment does not contain the third homopolymerized polypropylene, and the other is the same as example 1; the raw material for forming the core layer in this embodiment is 55% of the third random copolymerized polypropylene, 10% of the third impact polypropylene, 5% of the polyolefin elastomer and 30% of the third polypropylene recycled particles in terms of mass percentage, the third random copolymerized polypropylene is the random copolymer of propylene and ethylene, and the melting point is 142℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8g / 10min, and the density is 0.90g / cm 3 ; the third impact polypropylene is the copolymer of polypropylene and ethylene-propylene rubber, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6g / 10min, and the density is 0.90g / cm 3 ; the polyolefin elastomer is the copolymer of propylene and ethylene, the Vicat softening point of the polyolefin elastomer is 101℃, the melt mass flow rate under the condition of 190℃ / 2.16kg is 3g / 10min, and the density is 0.86g / cm 3 ; the melting point of the third polypropylene recycled particles is 145℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8.5g / 10min, and the density is 0.90g / cm 3 .

[0088] Example 12

[0089] This embodiment provides a CPP film, and the specific process is as follows:

[0090] The difference between this embodiment and example 1 is that the raw materials for forming the core layer are different. This embodiment does not contain the third impact polypropylene, and the other aspects are the same as example 1. The raw materials for forming the core layer in this embodiment are, in terms of mass percentage: the third random copolymerized polypropylene 50%, the third homopolymerized polypropylene 15%, the polyolefin elastomer 5%, and the third polypropylene recycled particles 30%. The third random copolymerized polypropylene is a random copolymer of propylene and ethylene, and the melting point is 142℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8 g / 10min, and the density is 0.90 g / cm 3 ; the melting point of the third homopolymerized polypropylene is 161℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 7.5 g / 10min, and the density is 0.91 g / cm 3 ; the polyolefin elastomer is a copolymer of propylene and ethylene, the Vicat softening point of the polyolefin elastomer is 101℃, the melt mass flow rate under the condition of 190℃ / 2.16kg is 3 g / 10min, and the density is 0.86 g / cm 3 ; the melting point of the third polypropylene recycled particles is 145℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8.5 g / 10min, and the density is 0.90 g / cm 3 .

[0091] Example 13

[0092] This embodiment provides a CPP film, and the specific process is as follows:

[0093] The difference between this embodiment and example 1 is that the raw materials for forming the core layer are different. This embodiment does not contain the polyolefin elastomer, and the other aspects are the same as example 1. The raw materials for forming the core layer in this embodiment are, in terms of mass percentage: the third random copolymerized polypropylene 45%, the third homopolymerized polypropylene 15%, the third impact polypropylene 10%, and the third polypropylene recycled particles 30%. The third random copolymerized polypropylene is a random copolymer of propylene and ethylene, and the melting point is 142℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 8 g / 10min, and the density is 0.90 g / cm 3 ; the melting point of the third homopolymerized polypropylene is 161℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 7.5 g / 10min, and the density is 0.91 g / cm 3 ; the third impact polypropylene is a copolymer of polypropylene and ethylene propylene rubber, and the melting point is 150℃, the melt mass flow rate under the condition of 230℃ / 2.16kg is 6.0 g / 10min, and the density is 0.90 g / cm 3; the third polypropylene recycled particles have a melting point of 145℃, a melt mass flow rate of 8.5 g / 10 min at 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 .

[0094] Example 14

[0095] This example provides a CPP film, and the specific process is as follows:

[0096] The difference between this example and Example 1 is that the core layer raw material is different, and this example does not contain third polypropylene recycled particles, and the other aspects are the same as Example 1; the core layer raw material of this example contains, by mass percentage, 70% of third random copolymerized polypropylene, 15% of third homopolymerized polypropylene, 10% of third impact polypropylene, and 5% of polyolefin elastomer; the third random copolymerized polypropylene is a propylene-ethylene random copolymer, has a melting point of 142℃, a melt mass flow rate of 8 g / 10 min at 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 ; the third homopolymerized polypropylene has a melting point of 161℃, a melt mass flow rate of 7.5 g / 10 min at 230℃ / 2.16 kg, and a density of 0.91 g / cm 3 ; the third impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, has a melting point of 150℃, a melt mass flow rate of 6.0 g / 10 min at 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 ; the polyolefin elastomer is a copolymer of propylene and ethylene, has a Vicat softening point of 101℃, a melt mass flow rate of 3 g / 10 min at 190℃ / 2.16 kg, and a density of 0.86 g / cm 3 .

[0097] Comparative Example 1

[0098] This comparative example provides a CPP film, and the specific process is as follows:

[0099] The difference between this comparative example and Example 1 is that the composite layer raw material is different, and this comparative example does not contain first polypropylene recycled particles, and the other aspects are the same as Example 1; the composite layer raw material of this comparative example contains, by mass percentage, 79% of first random copolymerized polypropylene, 10% of first homopolymerized polypropylene, 10% of first impact polypropylene, and 1% of silicon dioxide; the first random copolymerized polypropylene is a propylene-ethylene random copolymer, has a melting point of 150℃, a melt mass flow rate of 1.5 g / 10 min at 230℃ / 2.16 kg, and a density of 0.89 g / cm 3; the first homopolymer polypropylene has a melting point of 161℃, a melt mass flow rate of 7.5 g / 10 min at 230℃ / 2.16 kg, and a density of 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150℃, a melt mass flow rate of 6 g / 10 min at 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 .

[0100] Comparative Example 2

[0101] This comparative example provides a CPP film, and the specific process is as follows:

[0102] The difference between this comparative example and Example 1 is that the raw materials for forming the composite layer are different, and the first random copolymer polypropylene in this comparative example is different from that in Example 1, and the others are the same as in Example 1; in terms of mass percentage, the raw materials for forming the composite layer in this comparative example are: first random copolymer polypropylene 79%, first homopolymer polypropylene 5%, first impact polypropylene 5%, first polypropylene recycled particles 10%, and silicon dioxide 1%; the first random copolymer polypropylene is a propylene-ethylene random copolymer, and has a melting point of 140℃, a melt mass flow rate of 15 g / 10 min at 230℃ / 2.16 kg, and a density of 0.89 g / cm 3 ; the first homopolymer polypropylene has a melting point of 161℃, a melt mass flow rate of 7.5 g / 10 min at 230℃ / 2.16 kg, and a density of 0.91 g / cm 3 ; the first impact polypropylene is a copolymer of polypropylene and ethylene-propylene rubber, and has a melting point of 150℃, a melt mass flow rate of 6 g / 10 min at 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 ; the first polypropylene recycled particles have a melting point of 145℃, a melt mass flow rate of 8.5 g / 10 min at 230℃ / 2.16 kg, and a density of 0.90 g / cm 3 .

[0103] Performance test:

[0104] The CPP films of Examples 1-14 and Comparative Examples 1-2 were tested for performance according to the following method.

[0105] Corona value: tested according to GB / T 14216, and the test surface is the surface of the composite layer of the CPP film.

[0106] Table 1. Performance test results of CPP films.

[0107]

[0108] From Table 1, it can be seen that the CPP film of the present application has a high under-machine corona value and good corona retention effect.

[0109] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents after reading the present application. However, these modifications or changes are still within the scope of the present application.

Claims

1. A composite layer, characterized in that, The first raw material forming the composite layer, by mass percentage, comprises 30-80% first random copolymer polypropylene and 10-50% first recycled polypropylene particles. The first random copolymer polypropylene is a random copolymer of propylene and ethylene, with a melting point of 140-150°C, a melt flow rate of 1.5-11 g / 10 min at 230°C / 2.16 kg, and a density of 0.89-0.91 g / cm³. 3 The first recycled polypropylene particles have a melting point of 140~165℃, a melt mass flow rate of 3~9 g / 10 min at 230℃ / 2.16kg, and a density of 0.89~0.91 g / cm³. 3 .

2. The composite layer as described in claim 1, characterized in that, The first raw material further includes 0-30% of a first homopolymer polypropylene and 0-30% of a first impact-resistant polypropylene. The first homopolymer polypropylene has a melting point of 160-170°C, a melt flow rate of 3-8 g / 10 min at 230°C / 2.16 kg, and a density of 0.89-0.91 g / cm³. 3 The first impact-resistant polypropylene is a copolymer of polypropylene and ethylene propylene rubber, with a melting point of 150~165℃, a melt flow rate of 2~6 g / 10 min at 230℃ / 2.16kg, and a density of 0.89~0.91 g / cm³. 3 .

3. The composite layer as described in claim 1, characterized in that, The first raw material also includes 0-5% silicon dioxide.

4. A CPP film, said CPP film comprising a heat-sealing layer, a core layer, and a composite layer sequentially stacked, characterized in that, The composite layer is the composite layer according to any one of claims 1 to 3.

5. The CPP membrane as described in claim 4, characterized in that, The second raw material forming the heat-sealing layer, by mass percentage, comprises: 30-80% second random copolymer polypropylene, 0-20% second homopolymer polypropylene, and 0-50% second impact-resistant polypropylene. The second random copolymer polypropylene is a random copolymer of propylene and ethylene, with a melting point of 140-150°C, a melt flow rate of 1.5-11 g / 10 min at 230°C / 2.16 kg, and a density of 0.89-0.91 g / cm³. 3 The second homopolymer polypropylene has a melting point of 160~170℃, a melt flow rate of 3~8 g / 10 min at 230℃ / 2.16kg, and a density of 0.89~0.91 g / cm³. 3 The second impact-resistant polypropylene is a copolymer of polypropylene and ethylene propylene rubber, with a melting point of 150~165℃, a melt flow rate of 2~6 g / 10 min at 230℃ / 2.16kg, and a density of 0.89~0.91 g / cm³. 3 .

6. The CPP membrane as described in claim 5, characterized in that, The second raw material also includes 1-5% silica and 1-5% erucamide-type slip agent.

7. The CPP membrane as described in claim 5, characterized in that, The third raw material forming the core layer, by mass percentage, comprises: 0-80% recycled third polypropylene particles, 15-70% random copolymerized polypropylene, and 0-20% polyolefin elastomer. The recycled third polypropylene particles have a melting point of 140-165°C, a melt flow rate of 3-9 g / 10 min at 230°C / 2.16 kg, and a density of 0.89-0.91 g / cm³. 3 The third random copolymer polypropylene is a random copolymer of propylene and ethylene, with a melting point of 140~150℃, a melt flow rate of 1.5~11 g / 10min at 230℃ / 2.16kg, and a density of 0.89~0.91 g / cm³. 3 The polyolefin elastomer is a copolymer of propylene and ethylene. The Vicat softening point of the polyolefin elastomer is 45~110℃, the melt flow rate at 190℃ / 2.16kg is 1~9 g / 10 min, and the density is 0.86~0.90 g / cm³. 3 .

8. The CPP membrane as described in claim 7, characterized in that, The third raw material also includes 0-20% of a third homopolymer polypropylene, which has a melting point of 160-170℃, a melt flow rate of 3-8 g / 10 min at 230℃ / 2.16 kg, and a density of 0.89-0.91 g / cm³. 3 .

9. The CPP membrane as described in claim 7, characterized in that, The third raw material also includes 0-30% of a third impact-resistant polypropylene, which is a copolymer of polypropylene and ethylene propylene rubber, with a melting point of 150-165℃, a melt flow rate of 2-6 g / 10 min at 230℃ / 2.16 kg, and a density of 0.89-0.91 g / cm³. 3 .

10. A packaging material, characterized in that, It is prepared from the CPP membrane according to any one of claims 3 to 9.

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