CN117261386B - Cross-linked modified POF heat-shrinkable film and preparation method thereof - Google Patents
Cross-linked modified POF heat-shrinkable film and preparation method thereof Download PDFInfo
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- 229920006257 Heat-shrinkable film Polymers 0.000 title claims abstract description 29
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- 239000010410 layer Substances 0.000 claims abstract description 113
- 229920000092 linear low density polyethylene Polymers 0.000 claims abstract description 66
- 239000004707 linear low-density polyethylene Substances 0.000 claims abstract description 66
- -1 polypropylene Polymers 0.000 claims abstract description 64
- 239000004743 Polypropylene Substances 0.000 claims abstract description 37
- 229920001155 polypropylene Polymers 0.000 claims abstract description 37
- 239000002344 surface layer Substances 0.000 claims abstract description 35
- 239000004810 polytetrafluoroethylene Substances 0.000 claims abstract description 29
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims abstract description 29
- 229920005604 random copolymer Polymers 0.000 claims abstract description 18
- KOMNUTZXSVSERR-UHFFFAOYSA-N 1,3,5-tris(prop-2-enyl)-1,3,5-triazinane-2,4,6-trione Chemical compound C=CCN1C(=O)N(CC=C)C(=O)N(CC=C)C1=O KOMNUTZXSVSERR-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000003963 antioxidant agent Substances 0.000 claims abstract description 16
- 230000003078 antioxidant effect Effects 0.000 claims abstract description 16
- 229920001577 copolymer Polymers 0.000 claims abstract description 14
- 239000002994 raw material Substances 0.000 claims abstract description 11
- 238000004132 cross linking Methods 0.000 claims description 34
- 238000002156 mixing Methods 0.000 claims description 31
- 239000011347 resin Substances 0.000 claims description 30
- 229920005989 resin Polymers 0.000 claims description 30
- 230000005855 radiation Effects 0.000 claims description 13
- BGYHLZZASRKEJE-UHFFFAOYSA-N [3-[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxy]-2,2-bis[3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoyloxymethyl]propyl] 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate Chemical compound CC(C)(C)C1=C(O)C(C(C)(C)C)=CC(CCC(=O)OCC(COC(=O)CCC=2C=C(C(O)=C(C=2)C(C)(C)C)C(C)(C)C)(COC(=O)CCC=2C=C(C(O)=C(C=2)C(C)(C)C)C(C)(C)C)COC(=O)CCC=2C=C(C(O)=C(C=2)C(C)(C)C)C(C)(C)C)=C1 BGYHLZZASRKEJE-UHFFFAOYSA-N 0.000 claims description 11
- 239000000178 monomer Substances 0.000 claims description 11
- 238000001816 cooling Methods 0.000 claims description 10
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 6
- 239000005977 Ethylene Substances 0.000 claims description 6
- JKIJEFPNVSHHEI-UHFFFAOYSA-N Phenol, 2,4-bis(1,1-dimethylethyl)-, phosphite (3:1) Chemical compound CC(C)(C)C1=CC(C(C)(C)C)=CC=C1OP(OC=1C(=CC(=CC=1)C(C)(C)C)C(C)(C)C)OC1=CC=C(C(C)(C)C)C=C1C(C)(C)C JKIJEFPNVSHHEI-UHFFFAOYSA-N 0.000 claims description 5
- 238000013329 compounding Methods 0.000 claims description 5
- 239000012528 membrane Substances 0.000 claims description 5
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 5
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 5
- 238000001125 extrusion Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 230000001105 regulatory effect Effects 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 239000005022 packaging material Substances 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 238000007599 discharging Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 238000007493 shaping process Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000004804 winding Methods 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 238000007664 blowing Methods 0.000 description 3
- 239000000498 cooling water Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229920010126 Linear Low Density Polyethylene (LLDPE) Polymers 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000010096 film blowing Methods 0.000 description 1
- 238000001802 infusion Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920005629 polypropylene homopolymer Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D23/00—Producing tubular articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D7/00—Producing flat articles, e.g. films or sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/05—5 or more layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/24—All layers being polymeric
- B32B2250/242—All polymers belonging to those covered by group B32B27/32
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
- B32B2307/734—Dimensional stability
- B32B2307/736—Shrinkable
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
Abstract
The invention belongs to the technical field of packaging materials, and particularly relates to a cross-linked modified POF heat-shrinkable film and a preparation method thereof. The product provided by the invention comprises 5 layers of heat-shrinkable films, wherein each heat-shrinkable film comprises two opposite surface layers and three middle layers which are clamped between the two surface layers; wherein the surface layer is a polypropylene film; the middle layer is a linear low-density polyethylene film; the polypropylene film comprises the following raw materials in parts by weight: 80-100 parts of random copolymer polypropylene, 10-15 parts of styrene-isoprene-styrene copolymer, 1-1.5 parts of antioxidant and 1-2 parts of triallyl isocyanurate. In addition, the first middle layer also comprises polytetrafluoroethylene with the mass of 1.0% of the linear low-density polyethylene in the first middle layer; and the second intermediate layer further comprises polytetrafluoroethylene with the mass of 0.6% of the linear low-density polyethylene in the second intermediate layer.
Description
Technical Field
The invention belongs to the technical field of packaging materials. More particularly, to a cross-linked modified POF heat-shrinkable film and a preparation method thereof.
Background
The POF heat-shrinkable film is a 3-7-layer polyolefin composite co-extrusion biaxially oriented film (two-time film blowing stretching), has the advantages of good packaging fit, high transparency, strong toughness, high shrinkage speed, environmental protection and the like, is widely used for packaging cooked food, fruits, foods, books, electronic products and the like, and has huge application market. The non-radiation cross-linked POF heat-shrinkable film is characterized in that the surface layer is generally ternary Polymerization Polypropylene (PP), the middle layer is linear low-density polyethylene (LLDPE), the multilayer structure gives the advantages of LLDPE and PP, and meanwhile, the problems of incompatibility between layers, narrow heat-shrinkable window temperature, poor temperature resistance and the like exist, so that the application of the film is affected to a certain extent.
The defects of the POF heat-shrinkable film can be improved through radiation crosslinking modification, and the molecule chains between the layers are connected in a covalent bond mode, so that the compatibility is improved, the temperature resistance is enhanced, and the heat-shrinkable temperature window is widened.
The plastic processing and crosslinking process generally comprises two modes of crosslinking raw materials and radiation crosslinking. In theory, the crosslinking modifier is added into the raw materials to realize crosslinking among molecules, but because of the influence of the crosslinking process on the melt index, the process polymerization reaction is easy to generate, a large number of crystal points and other infusions are formed to influence the film making process, so that the production of the crosslinked film by adopting the crosslinking raw materials is very difficult, and the crosslinked film is generally produced by adopting a radiation crosslinking mode. Irradiation time and irradiation dose are key factors for controlling the crosslinking degree, and if excessive irradiation is performed, the polymer on the surface layer is easily cracked, so that the mechanical property and durability of the product are reduced.
Disclosure of Invention
The invention aims to solve the technical problems that when the traditional multilayer co-extrusion POF film is manufactured, the degree of crosslinking reaction is regulated and controlled to ensure the dimensional stability of the product, a certain degree of crosslinking is needed, and too high degree of crosslinking not only can reduce the flexibility of the product, but also can easily cause the cracking of the polymer on the surface of the product due to the requirement of too long irradiation time or irradiation dose, thereby influencing the mechanical property or durability of the product.
The invention aims to provide a cross-linked modified POF heat-shrinkable film.
The invention further aims to provide a preparation method of the cross-linked modified POF heat-shrinkable film.
The above object of the present invention is achieved by the following technical scheme:
the cross-linked modified POF heat-shrinkable film comprises 5 layers of heat-shrinkable films, wherein the heat-shrinkable films comprise two opposite surface layers and a three-layer middle layer which is clamped between the two surface layers;
wherein the surface layer is a polypropylene film; the middle layer is a linear low-density polyethylene film;
The polypropylene film comprises the following raw materials in parts by weight: 80-100 parts of random copolymer polypropylene, 10-15 parts of styrene-isoprene-styrene copolymer, 1-1.5 parts of antioxidant and 1-2 parts of triallyl isocyanurate.
Further, the random copolymer polypropylene is formed by co-polymerizing propylene monomer and ethylene monomer with the mass content of 2.5-3.5%.
Further, the antioxidant is prepared from an antioxidant 1010 and an antioxidant 168 according to the mass ratio of 1:1-1:1.5, compounding.
Further, the three-layer middle layer comprises a first middle layer and a second middle layer clamped on the two side surfaces of the first middle layer; wherein the first intermediate layer also comprises polytetrafluoroethylene with the mass of 0.9-1.0% of the linear low-density polyethylene in the first intermediate layer; and the second intermediate layer also comprises polytetrafluoroethylene with the mass of 0.6-0.8% of the linear low-density polyethylene in the second intermediate layer.
Further, the first intermediate layer further comprises polytetrafluoroethylene with the mass of 1.0% of the linear low-density polyethylene in the first intermediate layer; and the second intermediate layer further comprises polytetrafluoroethylene with the mass of 0.6% of the linear low-density polyethylene in the second intermediate layer.
The preparation method of the cross-linked modified POF heat-shrinkable film is characterized by comprising the following specific preparation steps:
Raw material preparation:
Uniformly mixing random copolymer polypropylene, a styrene-isoprene-styrene copolymer and an antioxidant, then adding triallyl isocyanurate, and carrying out blending extrusion to obtain resin for a surface layer;
linear low-density polyethylene is used as an intermediate layer resin;
After mixing, co-extruding to obtain a primary membrane tube, and after water cooling, performing primary radiation crosslinking;
And then carrying out traction, preheating, secondary inflation, air cooling, traction stretching and secondary radiation crosslinking in sequence to obtain the product.
Further, the specific preparation steps further include:
uniformly mixing linear low-density polyethylene and polytetrafluoroethylene, and then blending and extruding to obtain linear low-density polyethylene resin containing polytetrafluoroethylene, wherein the linear low-density polyethylene resin is used as an intermediate layer resin;
Wherein, the adding amount of polytetrafluoroethylene is regulated and controlled, and the linear low density polyethylene for the first middle layer and the second middle layer is respectively obtained.
The beneficial effects are that:
(1) Firstly, in a surface layer resin system, random copolymer polypropylene is used as matrix resin, and styrene-isoprene-styrene copolymer and triallyl isocyanurate are added; wherein, the triallyl isocyanurate molecular structure contains unsaturated-C=C-, and can be used as a functional auxiliary agent in the irradiation crosslinking process, thereby reducing the requirements on irradiation time and irradiation dosage and avoiding matrix resin cracking caused by excessive irradiation; the random copolymerized polypropylene is selected, and ethylene monomers are distributed irregularly in a polypropylene molecular chain, so that the crystallinity and the melting point of the material are lower, the triallyl isocyanurate molecules are uniformly dispersed in a resin system in the processing process, the effect is uniform, and local excessive crosslinking in the radiation crosslinking process can be avoided; and further adding the styrene-isoprene-styrene copolymer, which can change the flexible and smooth movement of the polypropylene molecular chains, so that the chain segment spacing is enlarged, the van der Waals force between the polypropylene resin molecular chains is weakened, and therefore, the polypropylene molecular chains can rapidly undergo a crosslinking reaction in the triallyl isocyanurate molecule in the irradiation process, the requirements on the irradiation time and the irradiation dosage are greatly weakened, and the surface polypropylene molecules are effectively prevented from being cracked under the irradiation action;
(2) According to the invention, polytetrafluoroethylene resin is further added into a linear low-density polyethylene resin system adopted by the middle layer, and firstly, the addition amount of the polytetrafluoroethylene resin is controlled so as to prevent agglomeration in the middle layer resin system after excessive addition, thereby affecting the uniformity of the crosslinking reaction; secondly, the heterogeneous nucleation can be achieved, so that the linear low-density polyethylene can be crystallized along the polytetrafluoroethylene fiber, and the intermediate layer resin system has a certain crystallinity, so that a certain mechanical property support is provided for the whole heat shrinkage film; in particular, by controlling the amount of polytetrafluoroethylene resin in the intermediate layer of the three layers, which is sandwiched in the intermediate layer of the second layer, to be lower than the amount in the other two layers, the crystallinity between the different layers can be controlled so that in the product, sufficient support is obtained at the interface where the linear low-density polyethylene layer and the polypropylene layer are bonded, so that a more stable crosslinking reaction process can be obtained in the radiation crosslinking process.
Detailed Description
The present invention is further illustrated below with reference to specific examples, which are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art.
Reagents and materials used in the following examples are commercially available unless otherwise specified.
Example 1
Raw material preparation:
Sequentially taking 85 parts of random copolymer polypropylene, 12 parts of styrene-isoprene-styrene copolymer, 1.2 parts of antioxidant and 1.5 parts of triallyl isocyanurate according to parts by weight;
wherein, the antioxidant is prepared from antioxidant 1010 and antioxidant 168 according to the mass ratio of 1:2, compounding; the random copolymer polypropylene is formed by co-polymerizing propylene monomer and ethylene monomer with the mass content of 2.8%;
uniformly mixing random copolymer polypropylene, a styrene-isoprene-styrene copolymer and an antioxidant, then adding triallyl isocyanurate, premixing, adding into an internal mixer, mixing for 4min at 150 ℃, and discharging to obtain resin for a surface layer;
mixing linear low-density polyethylene and polytetrafluoroethylene with the mass of 0.7% of that of the linear low-density polyethylene, adding antioxidant 1010 with the mass of 0.5% of that of the linear low-density polyethylene, premixing, adding into an internal mixer, mixing for 4min at 150 ℃, and discharging to obtain the linear low-density polyethylene for the second intermediate layer;
Mixing linear low-density polyethylene and polytetrafluoroethylene with the mass of 0.95% of that of the linear low-density polyethylene, adding antioxidant 1010 with the mass of 0.5% of that of the linear low-density polyethylene, premixing, adding into an internal mixer, mixing for 4min at 150 ℃, and discharging to obtain the linear low-density polyethylene for the first intermediate layer;
Preparation of the product:
The product comprises 5 layers of heat-shrinkable films, wherein each heat-shrinkable film comprises two opposite surface layers and three middle layers which are clamped between the two surface layers;
wherein the surface layer is a polypropylene film; the middle layer is a linear low-density polyethylene film;
The surface layer adopts the resin for the surface layer, and the three intermediate layers comprise a first intermediate layer and a second intermediate layer which is clamped on the two side surfaces of the first intermediate layer; the first middle layer is made of linear low-density polyethylene for the first middle layer; the second middle layer adopts linear low density polyethylene for the second middle layer;
Mixing the resin for the surface layer, the linear low-density polyethylene for the first middle layer and the linear low-density polyethylene for the second middle layer, melting and plasticizing by an extruder, feeding into a conical surface superposition machine head, extruding to obtain a primary membrane tube, cooling and shaping by an external cooling water ring and a shaping device, and performing primary irradiation crosslinking, wherein the radiation dose is controlled to be 55KGy;
And drawing, preheating, secondarily blowing, air cooling, drawing, secondarily radiating and crosslinking, and then winding into a rotary winding device to form a film, so as to obtain the product, wherein the pulling-up ratio is controlled to be 4.5, the blowing-up ratio is controlled to be 5.5, and the secondary radiating and crosslinking amount is controlled to be 35KGy.
Example 2
Raw material preparation:
according to the weight portions, sequentially taking 80 portions of random copolymer polypropylene, 10 portions of styrene-isoprene-styrene copolymer, 1 portion of antioxidant and 1 portion of triallyl isocyanurate;
wherein, the antioxidant is prepared from antioxidant 1010 and antioxidant 168 according to the mass ratio of 1:1, compounding; the random copolymer polypropylene is formed by co-polymerizing propylene monomer and ethylene monomer with the mass content of 2.5%;
uniformly mixing random copolymer polypropylene, a styrene-isoprene-styrene copolymer and an antioxidant, then adding triallyl isocyanurate, premixing, adding into an internal mixer, mixing for 3min at 150 ℃, and discharging to obtain resin for a surface layer;
Mixing linear low-density polyethylene and polytetrafluoroethylene with the mass of 0.6% of that of the linear low-density polyethylene, adding antioxidant 1010 with the mass of 0.5% of that of the linear low-density polyethylene, premixing, adding into an internal mixer, mixing for 3min at 150 ℃, and discharging to obtain the linear low-density polyethylene for the second intermediate layer;
Mixing linear low-density polyethylene and polytetrafluoroethylene with the mass of 1.0% of that of the linear low-density polyethylene, adding antioxidant 1010 with the mass of 0.5% of that of the linear low-density polyethylene, premixing, adding into an internal mixer, mixing for 3min at 150 ℃, and discharging to obtain the linear low-density polyethylene for the first intermediate layer;
Preparation of the product:
The product comprises 5 layers of heat-shrinkable films, wherein each heat-shrinkable film comprises two opposite surface layers and three middle layers which are clamped between the two surface layers;
wherein the surface layer is a polypropylene film; the middle layer is a linear low-density polyethylene film;
The surface layer adopts the resin for the surface layer, and the three intermediate layers comprise a first intermediate layer and a second intermediate layer which is clamped on the two side surfaces of the first intermediate layer; the first middle layer is made of linear low-density polyethylene for the first middle layer; the second middle layer adopts linear low density polyethylene for the second middle layer;
mixing the resin for the surface layer, the linear low-density polyethylene for the first middle layer and the linear low-density polyethylene for the second middle layer, melting and plasticizing by an extruder, feeding into a conical surface superposition machine head, extruding to obtain a primary membrane tube, cooling and shaping by an external cooling water ring and a shaping device, and performing primary irradiation crosslinking, wherein the radiation dose is controlled to be 50KGy;
And then drawing, preheating, secondarily blowing, air cooling, drawing, secondarily radiating and crosslinking, and then entering a rotary winding device for winding and forming a film to obtain the product, wherein the pulling-up ratio is controlled to be 4.2, the blowing-up ratio is controlled to be 5.3, and the secondary radiating and crosslinking amount is controlled to be 30KGy.
Example 3
Raw material preparation:
according to the weight portions, sequentially taking 100 portions of random copolymer polypropylene, 15 portions of styrene-isoprene-styrene copolymer, 1.5 portions of antioxidant and 2 portions of triallyl isocyanurate;
Wherein, the antioxidant is prepared from antioxidant 1010 and antioxidant 168 according to the mass ratio of 1:1.5, compounding; the random copolymer polypropylene is formed by co-polymerizing propylene monomer and ethylene monomer with the mass content of 3.5%;
Uniformly mixing random copolymer polypropylene, a styrene-isoprene-styrene copolymer and an antioxidant, then adding triallyl isocyanurate, premixing, adding into an internal mixer, mixing for 5min at 150 ℃, and discharging to obtain resin for a surface layer;
Mixing linear low-density polyethylene and polytetrafluoroethylene with the mass of 0.8% of that of the linear low-density polyethylene, adding antioxidant 1010 with the mass of 0.5% of that of the linear low-density polyethylene, premixing, adding into an internal mixer, mixing for 5min at 150 ℃, and discharging to obtain the linear low-density polyethylene for the second intermediate layer;
Mixing linear low-density polyethylene and polytetrafluoroethylene with the mass of 1.0% of that of the linear low-density polyethylene, adding antioxidant 1010 with the mass of 0.5% of that of the linear low-density polyethylene, premixing, adding into an internal mixer, mixing for 5min at 150 ℃, and discharging to obtain the linear low-density polyethylene for the first intermediate layer;
Preparation of the product:
The product comprises 5 layers of heat-shrinkable films, wherein each heat-shrinkable film comprises two opposite surface layers and three middle layers which are clamped between the two surface layers;
wherein the surface layer is a polypropylene film; the middle layer is a linear low-density polyethylene film;
The surface layer adopts the resin for the surface layer, and the three intermediate layers comprise a first intermediate layer and a second intermediate layer which is clamped on the two side surfaces of the first intermediate layer; the first middle layer is made of linear low-density polyethylene for the first middle layer; the second middle layer adopts linear low density polyethylene for the second middle layer;
Mixing the resin for the surface layer, the linear low-density polyethylene for the first middle layer and the linear low-density polyethylene for the second middle layer, melting and plasticizing by an extruder, feeding into a conical surface superposition machine head, extruding to obtain a primary membrane tube, cooling and shaping by an external cooling water ring and a shaping device, and performing primary irradiation crosslinking, wherein the radiation dose is controlled to be 60KGy;
And drawing, preheating, secondarily blowing, air cooling, drawing, secondarily radiating and crosslinking, and then winding into a rotary winding device to form a film, so as to obtain the product, wherein the pulling-up ratio is controlled to be 4.6, the blowing-up ratio is controlled to be 5.5, and the secondary radiating and crosslinking amount is controlled to be 40KGy.
Example 4
The difference between this embodiment and embodiment 1 is that: polytetrafluoroethylene is not added in the first intermediate layer, and the rest conditions remain unchanged.
Example 5
The difference between this embodiment and embodiment 1 is that: polytetrafluoroethylene is not added in the second intermediate layer, and the rest conditions remain unchanged.
Example 6
The difference between this embodiment and embodiment 1 is that: polytetrafluoroethylene is not added in the first intermediate layer and the second intermediate layer, and the rest conditions remain unchanged.
Comparative example 1
The difference between this comparative example and example 1 is that: equal-quality homo-polypropylene is adopted to replace random copolymer polypropylene, and the rest conditions are kept unchanged.
Comparative example 2
The difference between this comparative example and example 1 is that: no triallyl isocyanurate was added and the remaining conditions remained unchanged.
Comparative example 3
The difference between this comparative example and example 1 is that: no styrene-isoprene-styrene copolymer was added and the remaining conditions remained unchanged.
The products obtained in examples 1 to 6 and comparative examples 1 to 3 were subjected to performance tests, and specific test methods and test results are as follows:
gel content test:
1g of a sample is weighed and placed in dimethylbenzene according to GB/T18447-2001, the sample is boiled for 8 hours, washed with ethanol, dried and weighed, the gel content is calculated, and specific test results are shown in table 1;
Mechanical property test:
the tensile strength of the product is tested by referring to GB/T1040-2006, the thickness of a sample is not 1mm, the tensile speed is not 20mm/min, and the specific test results are shown in Table 1;
Table 1: product performance test results
| Gel content/% | Tensile Strength/MPa | |
| Example 1 | 82.5 | 20.2 |
| Example 2 | 84.6 | 22.3 |
| Example 3 | 83.8 | 21.0 |
| Example 4 | 81.5 | 19.2 |
| Example 5 | 81.2 | 19.1 |
| Example 6 | 80.2 | 18.5 |
| Comparative example 1 | 81.6 | 18.8 |
| Comparative example 2 | 65.5 | 16.2 |
| Comparative example 3 | 80.6 | 17.2 |
As shown by the test results in Table 1, the product obtained by the method has higher irradiation crosslinking degree, and on the basis, the obtained product has better mechanical properties.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.
Claims (6)
1. The cross-linked modified POF heat-shrinkable film is characterized by comprising 5 layers of heat-shrinkable films, wherein the heat-shrinkable films comprise two opposite surface layers and a three-layer middle layer which is clamped between the two surface layers;
wherein the surface layer is a polypropylene film; the middle layer is a linear low-density polyethylene film;
The polypropylene film comprises the following raw materials in parts by weight: 80-100 parts of random copolymer polypropylene, 10-15 parts of styrene-isoprene-styrene copolymer, 1-1.5 parts of antioxidant and 1-2 parts of triallyl isocyanurate; the three-layer middle layer comprises a first middle layer and a second middle layer clamped on the two side surfaces of the first middle layer; wherein the first intermediate layer also comprises polytetrafluoroethylene with the mass of 0.9-1.0% of the linear low-density polyethylene in the first intermediate layer; and the second intermediate layer also comprises polytetrafluoroethylene with the mass of 0.6-0.8% of the linear low-density polyethylene in the second intermediate layer.
2. The cross-linked modified POF heat-shrinkable film according to claim 1, wherein the random copolymer polypropylene is formed by co-polymerizing propylene monomer and ethylene monomer having a mass content of 2.5-3.5%.
3. The cross-linked modified POF heat-shrinkable film according to claim 1, wherein the antioxidant is prepared from an antioxidant 1010 and an antioxidant 168 in a mass ratio of 1:1-1:1.5, compounding.
4. The cross-linked modified POF heat-shrinkable film according to claim 1, wherein the first intermediate layer further comprises polytetrafluoroethylene having a mass of 1.0% of the linear low-density polyethylene in the first intermediate layer; and the second intermediate layer further comprises polytetrafluoroethylene with the mass of 0.6% of the linear low-density polyethylene in the second intermediate layer.
5. A method for producing the cross-linked modified POF heat-shrinkable film according to any one of claims 1 to 4, comprising the specific steps of:
Raw material preparation:
Uniformly mixing random copolymer polypropylene, a styrene-isoprene-styrene copolymer and an antioxidant, then adding triallyl isocyanurate, and carrying out blending extrusion to obtain resin for a surface layer;
linear low-density polyethylene is used as an intermediate layer resin;
After mixing, co-extruding to obtain a primary membrane tube, and after water cooling, performing primary radiation crosslinking;
And then carrying out traction, preheating, secondary inflation, air cooling, traction stretching and secondary radiation crosslinking in sequence to obtain the product.
6. The method for producing a cross-linked modified POF heat-shrinkable film according to claim 5, wherein the specific production step further comprises:
uniformly mixing linear low-density polyethylene and polytetrafluoroethylene, and then blending and extruding to obtain linear low-density polyethylene resin containing polytetrafluoroethylene, wherein the linear low-density polyethylene resin is used as an intermediate layer resin;
wherein, the adding amount of polytetrafluoroethylene is regulated and controlled, and the linear low density polyethylene for the first middle layer and the second middle layer is respectively obtained.
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|---|---|---|---|---|
| JPH11105222A (en) * | 1997-10-08 | 1999-04-20 | Asahi Chem Ind Co Ltd | Heat-shrinkable multilayered film |
| JP2002225203A (en) * | 2001-02-02 | 2002-08-14 | Grand Polymer Co Ltd | Olefinic multilayer shrink film and packaging material |
| CN105517793A (en) * | 2013-07-02 | 2016-04-20 | 艾利丹尼森公司 | Multilayer films and methods of manufacture |
| CN105882078A (en) * | 2014-10-08 | 2016-08-24 | 山东中塑泰富科技有限公司 | Technology for applying novel resin POE to POF polyolefin shrink film |
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2023
- 2023-09-12 CN CN202311168612.7A patent/CN117261386B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11105222A (en) * | 1997-10-08 | 1999-04-20 | Asahi Chem Ind Co Ltd | Heat-shrinkable multilayered film |
| JP2002225203A (en) * | 2001-02-02 | 2002-08-14 | Grand Polymer Co Ltd | Olefinic multilayer shrink film and packaging material |
| CN105517793A (en) * | 2013-07-02 | 2016-04-20 | 艾利丹尼森公司 | Multilayer films and methods of manufacture |
| CN105882078A (en) * | 2014-10-08 | 2016-08-24 | 山东中塑泰富科技有限公司 | Technology for applying novel resin POE to POF polyolefin shrink film |
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| 低能电子束辐射交联改性PP/LLDPE五层共挤POF热收缩膜的性能;张茂江;胡江涛;王明磊;邢哲;李荣;王洪龙;李会;吴国忠;;高分子材料科学与工程;20180503(第04期);全文 * |
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