CN110757925A

CN110757925A - BOPP film for high-temperature cooking compounding and preparation method thereof

Info

Publication number: CN110757925A
Application number: CN201910954345.3A
Authority: CN
Inventors: 彭超
Original assignee: Anhui Guofeng Plastic Industry Co Ltd
Current assignee: Anhui Guofeng Plastic Industry Co Ltd
Priority date: 2019-10-09
Filing date: 2019-10-09
Publication date: 2020-02-07

Abstract

The invention discloses a BOPP film for high-temperature cooking compounding, which sequentially consists of an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 90-95 parts by weight of homo-polypropylene, 1-5 parts by weight of SEBS thermoplastic elastomer and 1-5 parts by weight of anti-blocking master batch A; the raw materials of the anti-sticking master batch A consist of 30-50 parts of glass beads and 50-70 parts of homopolymerized polypropylene according to parts by weight; the core layer is prepared from 75-85 parts by weight of homopolymerized polypropylene and 15-25 parts by weight of SEBS thermoplastic elastomer; the raw materials of the heat sealing layer consist of 95 to 98 portions of ethylene-propylene-butylene terpolymer and 2 to 5 portions of anti-sticking master batch B according to the weight portion; the raw material of the anti-sticking master batch B comprises 30-50 parts of spherical silicon dioxide and 50-70 parts of polypropylene copolymer by weight. The invention also discloses a preparation method of the BOPP film.

Description

BOPP film for high-temperature cooking compounding and preparation method thereof

Technical Field

The invention relates to the technical field of BOPP films, in particular to a BOPP film for high-temperature cooking compounding and a preparation method thereof.

Background

With the development of economy, people increasingly like faster lives, including food. Fast food and various packaged foods are full of the daily aspects, in particular to foods packaged by high-temperature resistant steaming and boiling bags. However, many problems occur in the actual production, and the common quality problems are bag breaking and wrinkling of the packaging bag after cooking, peculiar smell after cooking and air leakage. As a sealing material for retort packaging, it is required to have not only good heat sealing properties but also high-temperature retort resistance, which facilitates sterilization and disinfection.

The high-temperature cooking CPP film sold in the market at present is easy to deform and wrinkle in a packaging bag under the sterilization condition of cooking at 121 ℃ for 30 minutes, and the heat resistance and the dimensional stability of the product are poor. The currently disclosed technology, such as the easy-to-peel high-temperature-cooking-resistant polypropylene film disclosed in chinese patent document CN108909123A, adopts a casting method to produce a polypropylene film, because the casting method does not perform stretch orientation treatment on polypropylene longitudinal and transverse molecular chains, the physical and mechanical properties of the film are poor, and the dimensional stability and heat resistance are insufficient, so that the film is difficult to adapt to the differentiated cooking packaging requirements.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a BOPP film for high-temperature cooking compounding and a preparation method thereof.

The BOPP film for high-temperature cooking compounding provided by the invention sequentially comprises an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 90-95 parts by weight of homo-polypropylene, 1-5 parts by weight of SEBS thermoplastic elastomer and 5-78 parts by weight of anti-blocking master batch A1; the raw materials of the anti-sticking master batch A consist of 30-50 parts of glass beads and 50-70 parts of homopolymerized polypropylene according to parts by weight;

the core layer is prepared from 75-85 parts by weight of homopolymerized polypropylene and 15-25 parts by weight of SEBS thermoplastic elastomer;

the raw materials of the heat sealing layer consist of 95-98 parts by weight of ethylene-propylene-butylene terpolymer and 2-5 parts by weight of anti-sticking master batch B; the raw material of the anti-sticking master batch B comprises 30-50 parts of spherical silicon dioxide and 50-70 parts of polypropylene copolymer by weight.

Preferably, the thickness of the BOPP film for high-temperature stewing composition is 30-70 mu m.

Preferably, the thickness of the anti-blocking layer is 5-10% of the thickness of the BOPP film, the thickness of the core layer is 70-80% of the thickness of the BOPP film, and the thickness of the heat sealing layer is 10-20% of the thickness of the BOPP film.

Preferably, the homopolypropylene has a degree of polymerization of 94-98% and a melt index of 2.0-2.5g/10 min.

Preferably, the glass beads have two particle size ranges, the particle size ranges are 1-2 μm and 2-4 μm, wherein the weight ratio of the glass beads with the particle size of 1-2 μm to the glass beads with the particle size of 2-4 μm is 0.5-1.5: 3.5-4.5.

Preferably, the spherical silica has a particle size of 1 to 3 μm.

The invention also provides a preparation method of the BOPP film for high-temperature cooking compounding, which comprises the following steps:

s1, heating and melting the core layer raw material to obtain a core layer melt; heating and melting raw materials of the anti-adhesion layer to obtain an anti-adhesion layer melt; heating and melting the heat seal layer raw material to obtain a heat seal layer melt;

s2, filtering the anti-adhesion layer melt, the core layer melt and the heat seal layer melt respectively, converging and extruding the three layers of T-shaped structure die head lips to form a membrane, attaching the membrane to a chill roll by a high-pressure air knife for quenching to form a cast sheet, and cooling and shaping by circulating water;

s3, longitudinally stretching the casting sheet to obtain a thick film, transversely stretching, heat setting, and naturally cooling to room temperature to obtain the BOPP film for high-temperature cooking compounding, wherein during longitudinal stretching, the preheating temperature of the anti-adhesion layer is 120-.

Preferably, in S3, the preheating temperature for transverse stretching is 175-185 ℃, the transverse stretching temperature is 150-160 ℃, and the transverse stretching multiple is 6-10 times.

Preferably, in S3, the heat-setting temperature is 160-170 ℃.

Preferably, in S1, the temperature for heating and melting the core layer raw material is 245-260 ℃.

Preferably, in S2, the chilled rolls have a temperature of 20-40 ℃ and the circulating water has a temperature of 20-45 ℃.

And in the step S3, introducing the BOPP film for high-temperature cooking and compounding into a traction system for flattening, measuring the thickness by a β ray thickness gauge, and rolling to obtain a finished product.

According to the invention, the core layer adopts the homo-polypropylene and SEBS thermoplastic elastomer with high polymerization degree and low melt index, and the crystallinity of the film is improved by adjusting process parameters, so that the heat resistance of the BOPP film can be effectively improved, and the BOPP film is beneficial to boiling without deformation and delamination under a high-temperature condition; the anti-blocking layer is made of homo-polypropylene, SEBS thermoplastic elastomer and anti-blocking master batch A for shallow screen printing with smaller granularity, so that the heat resistance and the printing performance of the BOPP film are further improved; the heat sealing layer adopts ethylene-propylene-butylene ternary polymerization and an anti-sticking master batch B heat sealing material, so that the BOPP has good heat sealing performance and lower initial heat sealing temperature; the invention provides a proper preparation method according to the BOPP film, and the anti-adhesion layer and the heat sealing layer are preheated at different temperatures during longitudinal stretching so as to prevent the heat sealing layer from being stuck on a roller; the BOPP film can also be suitable for the production line of common BOPP films.

The BOPP film for high-temperature cooking and compounding can meet the heat sealing and heat resisting requirements of various cooking packages, has heat resisting performance superior to that of a CPP film on the current market, has obvious capacity advantage and has strong market competitiveness.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to specific examples.

Example 1

A BOPP film for high-temperature cooking and compounding sequentially comprises an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 90 parts by weight of homopolymerized polypropylene, 5 parts by weight of SEBS thermoplastic elastomer and 5 parts by weight of anti-blocking master batch A; the raw materials of the anti-sticking master batch A consist of 30 parts of glass beads and 70 parts of homopolymerized polypropylene in parts by weight;

the core layer is prepared from 75 parts by weight of homopolymerized polypropylene and 25 parts by weight of SEBS thermoplastic elastomer;

the raw materials of the heat sealing layer consist of 95 parts of ethylene-propylene-butylene terpolymer and 5 parts of anti-sticking master batch B in parts by weight; the raw materials of the anti-sticking master batch B consist of 30 parts of spherical silicon dioxide and 70 parts of polypropylene copolymer in parts by weight.

The thickness of the BOPP film for high-temperature cooking compounding is 30 mu m; the thickness of the anti-adhesion layer is 5% of that of the BOPP film, the thickness of the core layer is 80% of that of the BOPP film, and the thickness of the heat-seal layer is 15% of that of the BOPP film;

the polymerization degree of the homopolymerized polypropylene is 94 percent, and the melt index is 2.0g/10 min; the particle size of the glass beads is 1 μm and 2 μm, wherein the weight ratio of the glass beads with the particle size of 1 μm to the glass beads with the particle size of 2 μm is 0.5: 4.5; the particle size of the spherical silica was 1 μm.

The preparation method of the BOPP film for high-temperature cooking compounding comprises the following steps:

s1, adding the core layer raw materials into a main extruder, and heating and melting at 245 ℃ to obtain a core layer melt; adding raw materials of the anti-adhesion layer into an auxiliary extruder, and heating and melting to obtain an anti-adhesion layer melt; adding the raw material of the heat seal layer into another auxiliary extruder, and heating and melting to obtain a melt of the heat seal layer;

s2, filtering the anti-adhesion layer melt, the core layer melt and the heat seal layer melt through a filter screen respectively, converging and extruding the three layers of T-shaped structure die head lips to form a membrane, attaching the membrane to a chilling roll with the temperature of 20 ℃ by using a high-pressure air knife to carry out chilling to form a cast sheet, and cooling and shaping the cast sheet by circulating water with the temperature of 25 ℃;

s3, taking a casting sheet, enabling the preheating temperature of the anti-adhesion layer to be 120 ℃, the preheating temperature of the heat sealing layer to be 100 ℃, longitudinally stretching the thick film by 4.5 times at 110 ℃ to obtain a thick film, taking the thick film, preheating the thick film at 175 ℃, transversely stretching the thick film by 6 times at 150 ℃, heat setting the thick film at 160 ℃, naturally cooling the thick film to room temperature to obtain a BOPP film for high-temperature cooking compounding, introducing the BOPP film for high-temperature cooking compounding into a traction system, flattening the film, measuring the thickness by a β ray thickness gauge, and rolling the film to obtain a finished product.

Example 2

A BOPP film for high-temperature cooking and compounding sequentially comprises an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 91 parts by weight of homopolymerized polypropylene, 4 parts by weight of SEBS thermoplastic elastomer and 5 parts by weight of anti-blocking master batch A; the raw materials of the anti-sticking master batch A consist of 35 parts of glass beads and 65 parts of homopolymerized polypropylene in parts by weight;

the core layer is prepared from 80 parts by weight of homopolymerized polypropylene and 20 parts by weight of SEBS thermoplastic elastomer;

the raw materials of the heat sealing layer consist of 96 parts of ethylene-propylene-butylene terpolymer and 4 parts of anti-sticking master batch B in parts by weight; the raw materials of the anti-sticking master batch B consist of 35 parts of spherical silicon dioxide and 65 parts of polypropylene copolymer by weight.

The thickness of the BOPP film for high-temperature cooking compounding is 40 mu m; the thickness of the anti-adhesion layer is 7% of that of the BOPP film, the thickness of the core layer is 78% of that of the BOPP film, and the thickness of the heat-seal layer is 15% of that of the BOPP film;

the polymerization degree of the homopolymerized polypropylene is 95 percent, and the melt index is 2.1g/10 min; the particle size of the glass beads is 1.5 microns and 3 microns, wherein the weight ratio of the glass beads with the particle size of 1.5 microns to the glass beads with the particle size of 3 microns is 1: 4; the particle size of the spherical silica was 2 μm.

s1, adding the core layer raw materials into a main extruder, and heating and melting at 250 ℃ to obtain a core layer melt; adding raw materials of the anti-adhesion layer into an auxiliary extruder, and heating and melting to obtain an anti-adhesion layer melt; adding the raw material of the heat seal layer into another auxiliary extruder, and heating and melting to obtain a melt of the heat seal layer;

s2, filtering the anti-adhesion layer melt, the core layer melt and the heat seal layer melt through a filter screen respectively, converging and extruding the three layers of T-shaped structure die head lips to form a membrane, attaching the membrane to a chilling roll at 25 ℃ by using a high-pressure air knife to quench to form a cast sheet, and cooling and shaping the cast sheet by circulating water at 30 ℃;

s3, taking a casting sheet, enabling the preheating temperature of the anti-adhesion layer to be 130 ℃, the preheating temperature of the heat sealing layer to be 105 ℃, longitudinally stretching the thick film by 4.7 times at 115 ℃ to obtain a thick film, taking the thick film, preheating the thick film at 177 ℃, transversely stretching the thick film by 7 times at 152 ℃, heat setting the thick film at 162 ℃, naturally cooling the thick film to room temperature to obtain a BOPP film for high-temperature cooking compounding, introducing the BOPP film for high-temperature cooking compounding into a traction system, flattening the film, measuring the thickness by a β ray thickness gauge, and rolling the film to obtain a finished product.

Example 3

A BOPP film for high-temperature cooking and compounding sequentially comprises an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 92 parts of homopolymerized polypropylene, 4 parts of SEBS thermoplastic elastomer and 4 parts of anti-blocking master batch; the raw materials of the anti-sticking master batch A consist of 40 parts of glass beads and 60 parts of homopolymerized polypropylene in parts by weight;

the core layer is prepared from 85 parts by weight of homopolymerized polypropylene and 15 parts by weight of SEBS thermoplastic elastomer;

the raw materials of the heat sealing layer consist of 97 parts by weight of ethylene-propylene-butylene terpolymer and 3 parts by weight of anti-sticking master batch B; the raw materials of the anti-sticking master batch B consist of 40 parts of spherical silicon dioxide and 60 parts of polypropylene copolymer according to parts by weight.

The thickness of the BOPP film for high-temperature cooking compounding is 50 mu m; the thickness of the anti-adhesion layer is 8% of that of the BOPP film, the thickness of the core layer is 75% of that of the BOPP film, and the thickness of the heat-seal layer is 17% of that of the BOPP film;

the polymerization degree of the homopolymerized polypropylene is 96 percent, and the melt index is 2.2g/10 min; the particle size of the glass beads is 2 microns and 4 microns, wherein the weight ratio of the glass beads with the particle size of 2 microns to the glass beads with the particle size of 4 microns is 1.5: 3.5; the spherical silica had a particle size of 3 μm.

s1, adding the core layer raw materials into a main extruder, and heating and melting at 255 ℃ to obtain a core layer melt; adding raw materials of the anti-adhesion layer into an auxiliary extruder, and heating and melting to obtain an anti-adhesion layer melt; adding the raw material of the heat seal layer into another auxiliary extruder, and heating and melting to obtain a melt of the heat seal layer;

s2, filtering the anti-adhesion layer melt, the core layer melt and the heat seal layer melt through a filter screen respectively, converging and extruding the three layers of T-shaped structure die head lips to form a membrane, attaching the membrane to a chilling roller with the temperature of 30 ℃ by using a high-pressure air knife for chilling to form a cast sheet, and cooling and shaping the cast sheet by circulating water with the temperature of 35 ℃;

s3, taking a casting sheet, enabling the preheating temperature of the anti-adhesion layer to be 140 ℃, the preheating temperature of the heat-sealing layer to be 110 ℃, longitudinally stretching the thick film by 4.9 times at 120 ℃ to obtain a thick film, taking the thick film, preheating the thick film at 180 ℃, transversely stretching the thick film by 8 times at 154 ℃, heat-setting the thick film at 164 ℃, naturally cooling the thick film to room temperature to obtain a BOPP film for high-temperature cooking compounding, introducing the BOPP film for high-temperature cooking compounding into a traction system, flattening the film, measuring the thickness by a β ray thickness gauge, and rolling the film to obtain a finished product.

Example 4

A BOPP film for high-temperature cooking and compounding sequentially comprises an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 93 parts of homopolymerized polypropylene, 4 parts of SEBS thermoplastic elastomer and 3 parts of anti-blocking master batch; the raw materials of the anti-sticking master batch A consist of 45 parts of glass beads and 55 parts of homopolymerized polypropylene in parts by weight;

the raw materials of the heat sealing layer consist of 98 parts of ethylene-propylene-butylene terpolymer and 2 parts of anti-sticking master batch B in parts by weight; the raw materials of the anti-sticking master batch B consist of 45 parts of spherical silicon dioxide and 55 parts of polypropylene copolymer in parts by weight.

The thickness of the BOPP film for high-temperature cooking compounding is 60 mu m; the thickness of the anti-adhesion layer is 9% of that of the BOPP film, the thickness of the core layer is 72% of that of the BOPP film, and the thickness of the heat-seal layer is 19% of that of the BOPP film;

the polymerization degree of the homopolymerized polypropylene is 97 percent, and the melt index is 2.3g/10 min; the particle size of the glass beads is 2 microns and 4 microns, wherein the weight ratio of the glass beads with the particle size of 2 microns to the glass beads with the particle size of 4 microns is 1.5: 3.5; the spherical silica had a particle size of 3 μm.

s1, adding the core layer raw materials into a main extruder, and heating and melting at 260 ℃ to obtain a core layer melt; adding raw materials of the anti-adhesion layer into an auxiliary extruder, and heating and melting to obtain an anti-adhesion layer melt; adding the raw material of the heat seal layer into another auxiliary extruder, and heating and melting to obtain a melt of the heat seal layer;

s2, filtering the anti-adhesion layer melt, the core layer melt and the heat seal layer melt through a filter screen respectively, converging and extruding the three layers of T-shaped structure die head lips to form a membrane, attaching the membrane to a chilling roller with the temperature of 35 ℃ by using a high-pressure air knife for chilling to form a cast sheet, and cooling and shaping the cast sheet by circulating water with the temperature of 40 ℃;

s3, taking a casting sheet, enabling the preheating temperature of the anti-adhesion layer to be 150 ℃, the preheating temperature of the heat sealing layer to be 115 ℃, longitudinally stretching the thick film by 5.0 times at 125 ℃ to obtain a thick film, taking the thick film, preheating the thick film at 182 ℃, transversely stretching the thick film by 9 times at 156 ℃, heat setting the thick film at 166 ℃, naturally cooling the thick film to room temperature to obtain a BOPP film for high-temperature cooking compounding, introducing the BOPP film for high-temperature cooking compounding into a traction system, flattening the film, measuring the thickness by a β ray thickness gauge, and rolling the film to obtain a finished product.

Example 5

A BOPP film for high-temperature cooking and compounding sequentially comprises an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 95 parts by weight of homopolymerized polypropylene, 3 parts by weight of SEBS thermoplastic elastomer and 2 parts by weight of anti-blocking master batch A; the raw materials of the anti-sticking master batch A consist of 50 parts of glass beads and 50 parts of homopolymerized polypropylene in parts by weight;

the raw materials of the heat sealing layer consist of 98 parts of ethylene-propylene-butylene terpolymer and 2 parts of anti-sticking master batch B in parts by weight; the raw materials of the anti-sticking master batch B consist of 50 parts of spherical silicon dioxide and 50 parts of polypropylene copolymer according to parts by weight.

The thickness of the BOPP film for high-temperature cooking compounding is 70 mu m; the thickness of the anti-adhesion layer is 10% of that of the BOPP film, the thickness of the core layer is 70% of that of the BOPP film, and the thickness of the heat-seal layer is 20% of that of the BOPP film;

the polymerization degree of the homopolymerized polypropylene is 98 percent, and the melt index is 2.5g/10 min; the particle size of the glass beads is 2 microns and 4 microns, wherein the weight ratio of the glass beads with the particle size of 2 microns to the glass beads with the particle size of 4 microns is 1.5: 3.5; the spherical silica had a particle size of 3 μm.

s2, filtering the anti-adhesion layer melt, the core layer melt and the heat seal layer melt through a filter screen respectively, converging and extruding the three layers of T-shaped structure die head lips to form a membrane, attaching the membrane to a chilling roller at 40 ℃ by using a high-pressure air knife to quench to form a cast sheet, and cooling and shaping the cast sheet by circulating water at 45 ℃;

s3, taking a casting sheet, enabling the preheating temperature of the anti-adhesion layer to be 150 ℃, the preheating temperature of the heat sealing layer to be 120 ℃, longitudinally stretching the thick film by 5.2 times at 130 ℃ to obtain a thick film, preheating the thick film at 185 ℃, transversely stretching the thick film by 10 times at 160 ℃, heat setting the thick film at 170 ℃, naturally cooling the thick film to room temperature to obtain a BOPP film for high-temperature cooking compounding, introducing the BOPP film for high-temperature cooking compounding into a traction system for flattening, measuring the thickness by a β ray thickness gauge, and rolling to obtain a finished product.

Comparative example

The polypropylene film is prepared according to an easy-stripping high-temperature-cooking-resistant polypropylene film disclosed in patent CN 108909123A.

The samples obtained in examples 1 to 5 and comparative example were tested and the results are shown in the following table:

as can be seen from the above table, the films obtained in examples 1 to 5 all had lower heat shrinkage, lower initial heat-sealing temperature and tensile strength significantly superior to those of comparative example, and the physical mechanical properties and impact resistance of examples 1 to 5 were significantly superior to those of comparative example.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. The BOPP film for high-temperature cooking compounding is characterized by sequentially comprising an anti-adhesion layer, a core layer and a heat sealing layer; the anti-blocking layer is prepared from 90-95 parts by weight of homo-polypropylene, 1-5 parts by weight of SEBS thermoplastic elastomer and 5-78 parts by weight of anti-blocking master batch A1; the raw materials of the anti-sticking master batch A consist of 30-50 parts of glass beads and 50-70 parts of homopolymerized polypropylene according to parts by weight;

2. The BOPP film for high-temperature retort compounding of claim 1, wherein the thickness of the BOPP film for high-temperature retort compounding is 30 to 70 μm.

3. The BOPP film for high-temperature cooking compounding according to claim 1 or 2, wherein the anti-adhesion layer is 5-10% of the thickness of the BOPP film, the core layer is 70-80% of the thickness of the BOPP film, and the heat-seal layer is 10-20% of the thickness of the BOPP film.

4. BOPP film for autoclaving compounding according to any of the claims 1 to 3, wherein the homo-polypropylene has a degree of polymerization of 94 to 98% and a melt index of 2.0 to 2.5g/10 min.

5. A BOPP film for autoclaving compounding as set forth in any one of claims 1 to 4, wherein the glass beads have two particle size ranges, the particle size ranges being between 1 and 2 μm and between 2 and 4 μm, wherein the weight ratio of glass beads having a particle size of between 1 and 2 μm to glass beads having a particle size of between 2 and 4 μm is between 0.5 and 1.5: 3.5-4.5.

6. BOPP film for autoclaving compounding according to any one of the claims 1 to 5, wherein the spherical silica has a particle size in the range of 1 to 3 μm.

7. A method for preparing the BOPP film for the high-temperature cooking composite according to any one of claims 1 to 6, which comprises the following steps:

8. The method as claimed in claim 7, wherein the preheating temperature for transverse stretching is 175-185 ℃, the transverse stretching temperature is 150-160 ℃, and the transverse stretching ratio is 6-10 times in S3.

9. The method for preparing a BOPP film for autoclaving compounding as set forth in claim 7 or 8, wherein the heat setting temperature is 160-170 ℃ in S3.

10. The preparation method of the BOPP film for high-temperature cooking and compounding as claimed in any one of claims 7 to 9, wherein in S1, the temperature for heating and melting the raw material of the core layer is 245-260 ℃; preferably, in S2, the chilled rolls have a temperature of 20-40 ℃ and the circulating water has a temperature of 20-45 ℃.