CN103252961A - Polyethylene film and preparation method thereof - Google Patents
Polyethylene film and preparation method thereof Download PDFInfo
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- CN103252961A CN103252961A CN2012100412657A CN201210041265A CN103252961A CN 103252961 A CN103252961 A CN 103252961A CN 2012100412657 A CN2012100412657 A CN 2012100412657A CN 201210041265 A CN201210041265 A CN 201210041265A CN 103252961 A CN103252961 A CN 103252961A
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Abstract
The invention provides a polyethylene film and a preparation method thereof. The film comprises a polyethylene core layer and a smooth surface layer adhered to at least one side surface of the polyethylene core layer. The smooth surface layer is a polyethylene layer with dispersed self-lubricating micro-particles. Fusion index of the polyethylene in the polyethylene core layer and the smooth surface layer under 190 DEG C and 2.16kg are 0.5-5g/10min, and preferably 1-3.5g/10min. The self-lubricating micro-particles are high-molecular micro-particles with melting temperature higher than or equal to 250 DEG C and with both static friction coefficient and dynamic friction coefficient smaller than or equal to 0.6. The polyethylene film provided by the invention has excellent smooth performance, optical performance, and mechanical performance.
Description
Technical field
The present invention relates to a kind of polyethylene film and preparation method thereof.
Background technology
Biaxially-oriented polyethylene film (BOPE film) has excellent chemical stability, heat sealability, resistance to water and the permeability that blocks water, be desirable packaging material, be widely used in the packing of food, vegetables and fruits, infant article etc., occupy very consequence in market.Yet, the BOPE film is the same with most of plastic sheetings to have that coefficient of friction is big, frictional static is serious, defective such as adhesion easily between the film, requires film to have the Application for Field of good smooth performance thereby limited it at high-speed packaging, lubricated barrier film etc.
The defective that generally adopts at present the method for adding slipping agent in the polyethylene film to reduce the coefficient of friction of polyethylene film and improve its easy adhesion improves its smooth property.Slipping agent commonly used is divided into inorganic and organic two classes usually.Inorganic slipping agent comprises calcium carbonate, mica, silica etc.In order to reduce the caking property between the film, the smooth performance on raising top layer, need to improve the addition of inorganic slipping agent usually.But inorganic slipping agent is normally opaque, and the increase of slipping agent consumption can cause the optical property variation of polyethylene film, is not suitable for transparency and glossiness are had the production and processing of the film of requirement.Organic class slipping agent is generally amine or silicone organic matter.Wherein, silicone is liquid, adds and uses inconvenience.The amine slipping agent is the migration-type additive, the method of adding the amine slipping agent in the film is mainly and amine slipping agent and polyvinyl resin are mixed the back processes film forming, after but gained polyvinyl resin film must be placed 7-10 days, treat just can reach smooth performance preferably after slipping agent is moved to the surface of polyvinyl resin film, therefore, production efficiency is lower; What is more important, Qian Yi slipping agent can not remain in the polyethylene film and cause the optical property of film and mechanical property significantly to reduce, thereby has had a strong impact on its application in practice.
Summary of the invention
The objective of the invention is in order to overcome when adopting existing method to prepare polyethylene film, needs placement a period of time just can reach its smooth effect, production efficiency is lower, and the defective that the optical property of the polyethylene film that obtains and mechanical property are not good, and a kind of preparation method that can reach the higher polyethylene film of its smooth effect and productive rate that do not need to place is provided, and the polyethylene film that obtains has excellent smooth performance, optical property and mechanical property concurrently.
The invention provides a kind of polyethylene film, wherein, described film comprises the polyethylene sandwich layer and is attached to the smooth superficial layer of at least one side surface of described polyethylene sandwich layer that described smooth superficial layer is the polyethylene layer that is dispersed with the self-lubricating particulate; Polyethylene in described polyethylene sandwich layer and the smooth superficial layer is 0.5g/10min-5g/10min at 190 ℃, the melt index of 2.16kg, is preferably 1g/10min-3.5g/10min; Described self-lubricating particulate be melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle.
The present invention also provides a kind of preparation method of polyethylene film, and wherein, this method comprises sends into melting mixing and extruding pelletization in the extruder after polyethylene and self-lubricating particulate mixed, and obtains smooth superficial layer raw material; Described smooth superficial layer raw material and polyethylene sent into have extruding of multi-layer co-extruded structure and extrude curtain coating in the casting apparatus, obtain the cast-sheet of the smooth superficial layer of at least one side surface of comprising the polyethylene sandwich layer and being attached to described polyethylene sandwich layer; And the cast-sheet that obtains carried out biaxial tension, obtain the Biaxially-oriented polyethylene film of the smooth superficial layer of at least one side surface of comprising the polyethylene sandwich layer and being attached to described polyethylene sandwich layer; Described smooth superficial layer is the polyethylene layer that is dispersed with the self-lubricating particulate; Polyethylene in described polyethylene sandwich layer and the smooth superficial layer is 0.5g/10min-5g/10min at 190 ℃, the melt index of 2.16kg, is preferably 1g/10min-3.5g/10min; Described self-lubricating particulate be melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle.
On the one hand, after the self-lubricating particulate adds smooth superficial layer to, because the incompatibility of described self-lubricating particulate and polyethylene matrix, particulate can be arranged automatically, disperse, and can break through or be embedded on the described film top layer, form the self-lubricating point at film surface, thereby can effectively reduce the coefficient of friction of polyethylene film, and the bonding between the reduction polyethylene film, it is outstanding to make it smooth performance.Further, adopt method of the present invention to prepare polyethylene film, need not to wait for that the self-lubricating particulate migration to the top layer of described film, can improve the production efficiency of film.In addition, because the smooth performance of polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and polyether-ether-ketone particulate is very excellent, melt temperature is higher, optical property is better, therefore, a preferred embodiment of the invention, when described self-lubricating particulate was selected from polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and the polyether-ether-ketone particulate one or more, the combination property of the polyethylene film that obtains was very good.
Other features and advantages of the present invention will partly be described in detail in the specific embodiment subsequently.
The specific embodiment
Below the specific embodiment of the present invention is elaborated.Should be understood that the specific embodiment described herein only is used for description and interpretation the present invention, is not limited to the present invention.
According to the present invention, described polyethylene film comprises the polyethylene sandwich layer and is attached to the smooth superficial layer of at least one side surface of described polyethylene sandwich layer that described smooth superficial layer is the polyethylene layer that is dispersed with the self-lubricating particulate; Polyethylene in described polyethylene sandwich layer and the smooth superficial layer is 0.5g/10min-5g/10min at 190 ℃, the melt index of 2.16kg, is preferably 1g/10min-3.5g/10min; Described self-lubricating particulate be melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle.
Described polyethylene is to be a kind of thermoplastic resin that raw material is produced with ethene, has good low-temperature resistance performance (minimum serviceability temperature can reach-70 ℃ to-100 ℃), and chemically stable and corrosion resistance are widely used in the packing of food.In polyethylene film provided by the invention, described polyethylene can be commercially available, for example can be available from Maoming petrochemical industry, Exxon Mobil Corporation etc.Under the preferable case, poly density is that 0.9-0.97 gram/cubic centimetre, melt temperature are 110-132 ℃.
According to the present invention, described self-lubricating particulate refers to have the granular high temperature resistant high molecular particle of self-lubricating property.The adding of self-lubricating particulate in the described smooth top layer can make the coefficient of friction of the polyethylene film of production significantly reduce, and the smooth performance of film increases substantially.
According to the present invention, the content of described self-lubricating particulate can change in relative broad range, it will be understood by those skilled in the art that the content of described self-lubricating particulate is more big, smooth performance is more good, but optical property and mechanical property may descend to some extent, and therefore, performance synthesis is from every side considered, under the preferable case, gross mass with described smooth superficial layer is benchmark, and the content of described self-lubricating particulate is 0.05-10 weight %, more preferably 0.5-3 weight %.
According to the present invention, the thickness of described polyethylene sandwich layer and the thickness of smooth superficial layer can suitably be selected according to the service condition of described polyethylene film, if the described polyethylene film of conditional request of described use has bigger mechanical strength and lower to the optical property requirement, then the thickness of the thickness of described polyethylene sandwich layer and smooth superficial layer can be thicker; If the described polyethylene film of conditional request of described use has preferably light transmission and mechanical strength required lower, then the thickness of the thickness of described polyethylene sandwich layer and smooth superficial layer can be thinner.Generally, the thickness of described polyethylene sandwich layer can be the 5-100 micron, and the thickness of the smooth superficial layer of described polyethylene sandwich layer one side can be the 0.1-10 micron; In order further to improve the combination property of the polyethylene film that obtains, under the preferable case, the thickness of described polyethylene sandwich layer can be the 10-40 micron, and the thickness of the smooth superficial layer of described polyethylene sandwich layer one side can be the 1-3 micron.Correspondingly, the particle diameter of described self-lubricating particulate is the 0.1-20 micron, is preferably the 0.1-6 micron.When the particle diameter of described self-lubricating particulate was the 100%-200% of thickness of smooth superficial layer of described polyethylene sandwich layer one side, the smooth performance of polyethylene film of the present invention was very good.
According to the present invention, although the kind of described self-lubricating particulate can not cause remarkable influence to the smooth performance of the polyethylene film that obtains, as long as be selected from melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle and get final product, but in order to obtain frictional behaviour, glossiness and mechanical property be more excellent polyethylene film all, and can further guarantee the even dispersion of described self-lubricating particle, under the preferable case, described high molecular particle is selected from the polytetrafluoroethylene (PTFE) particulate, medlin particulate, in polyamide particles and the polyether-ether-ketone particulate one or more.The present inventor finds by further investigation, when described self-lubricating particulate is selected from polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and the polyether-ether-ketone particulate one or more, and when the particle diameter of described self-lubricating particulate was the 100%-200% of thickness of smooth superficial layer of described polyethylene sandwich layer one side, the combination property of the polyethylene film of gained was splendid.Infer that reason may be: described polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and polyether-ether-ketone particulate itself have good self-lubricating property, can give film surface good smooth property, and above several self-lubricating high molecular particle stable in properties, can be high temperature resistant, melt temperature is all more than 250 ℃, therefore fusion can not take place in the process of polyethylene film, can keep particulate form at the film surface layer, thereby stable smooth performance can be provided.In addition, when the particle diameter of described self-lubricating particulate is the 100%-200% of thickness of smooth superficial layer of described polyethylene sandwich layer one side, can guarantee that the self-lubricating particulate is embedded among the superficial layer and has part to protrude from superficial layer, not only can give full play to its smooth characteristic, also be unlikely in processing or use, to fall from the film surface pull-up, thereby make that the smooth performance of film is more lasting.In addition, a preferred embodiment of the invention, when the gross mass with described smooth superficial layer is benchmark, the content of described self-lubricating particulate is 0.05-10 weight %, when being preferably 0.5-3 weight %, not only can the light transmission of film not impacted, can also significantly improve durability and the heat-resistant stability of described film.
According to the present invention, described self-lubricating particulate can be by commercially available and prepare according to existing method, and for example, described polytetrafluoroethylene (PTFE) particulate can be available from Su Wei group, the trade mark is F284, and melt temperature is that 327-333 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.04 and 0.04; Described medlin particulate can be available from Hubei bismaleimide resin factory, and the trade mark is SM003, perhaps can prepare according to the CN101253223A disclosed method, and its melt temperature is that 330-350 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.06 and 0.06; Described polyamide particles can be available from the Guangzhou Long Suliaocailiaochang that escapes, the trade mark is A102F, perhaps can prepare according to CN 101357989A disclosed method, its melt temperature can be respectively 0.42 and 0.35 for 255-265 ℃, confficient of static friction and the coefficient of kinetic friction; Described polyether-ether-ketone particulate can be available from Britain Wei Gesi company, and melt temperature is that 334-340 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.2 and 0.2.
The preparation method of polyethylene film provided by the invention comprises and sends into melting mixing and extruding pelletization in the extruder after polyethylene and self-lubricating particulate mixed, and obtains smooth superficial layer raw material; Described smooth superficial layer raw material and polyethylene sent into have extruding of multi-layer co-extruded structure and extrude curtain coating in the casting apparatus, obtain the cast-sheet of the smooth superficial layer of at least one side surface of comprising the polyethylene sandwich layer and being attached to described polyethylene sandwich layer; And the cast-sheet that obtains carried out biaxial tension, obtain the Biaxially-oriented polyethylene film of the smooth superficial layer of at least one side surface of comprising the polyethylene sandwich layer and being attached to described polyethylene sandwich layer; Described smooth superficial layer is the polyethylene layer that is dispersed with the self-lubricating particulate; Polyethylene in described polyethylene sandwich layer and the smooth superficial layer is 0.5g/10min-5g/10min at 190 ℃, the melt index of 2.16kg, is preferably 1g/10min-3.5g/10min; Described self-lubricating particulate be melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle.Under the preferable case, described high molecular particle is selected from one or more in polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and the polyether-ether-ketone particulate.
According to the present invention; in order to obtain the more excellent polyethylene film of performance; under the preferable case; this method also is included in before polyethylene and the mixing of self-lubricating particulate; and before described smooth superficial layer raw material and polyvinyl resin are sent into casting machine, polyethylene and self-lubricating particulate are carried out drying.The method of described drying and condition can for example, can be vacuum drying, forced air drying etc. for well known to a person skilled in the art drying means and condition, and baking temperature can be 60-100 ℃.Drying equipment is generally and comprises that heating, heated drying air purge or the drying equipment of vacuum system, for example, can be continuous dryer, vacuum drying oven and hot-air oven etc.
Usually, the mode that mixes of described polyvinyl resin and self-lubricating particulate can be even for described polyethylene and self-lubricating particulate being joined in the existing various mixing apparatus blended under agitation.Wherein, described mixing apparatus for example can be mixer, kneader, mill and banbury etc.The temperature and time of blended under agitation is conventionally known to one of skill in the art, and for example, the temperature of blended under agitation can be 25-65 ℃, and the time of blended under agitation can be 5-30 minute, and the rotating speed of blended under agitation can be 50-300 rev/min; Under the preferable case, under 50-100 rev/min rotating speed, stirred 5-15 minute earlier, and then under 100-200 rev/min rotating speed, stirred 5-15 minute.
According to the present invention, it is conventionally known to one of skill in the art that the described mixture that obtains after polyethylene and self-lubricating particulate are mixed carries out method, condition and used extruder that melting mixing and extruding pelletization obtain smooth superficial layer raw material.For example, double screw extruder can be adopted, also single screw extrusion machine can be adopted, screw speed is 150-360 rev/min, each zone temperatures is respectively 150-220 ℃, 160-230 ℃, 160-230 ℃, 170-240 ℃, 170-240 ℃, 170-240 ℃, and the vacuum of each section is extruding pelletization under the condition of 0.02 to 0.09 MPa.Vacuum in this specification refers to the absolute value of the difference of absolute pressure and atmospheric pressure.
Need to prove, extrude casting apparatus and generally include a plurality of extruders, can different materials be heated in a plurality of extruders, and can comprise that at least two-layer MULTILAYER COMPOSITE die head extrudate flow prolongs by same through the material after the different extruder heating, thereby obtain comprising the cast-sheet of multilayer; Wherein, the material in each extruder is extruded from wherein one deck of described MULTILAYER COMPOSITE die head.Therefore, what those skilled in the art should be readily appreciated that is, when a side surface that obtains the polyethylene sandwich layer when needs is attached with the polyethylene film of smooth superficial layer, can adopt two different extruders with described smooth superficial layer raw material and polyethylene fusion, and molten product comprised that by same two-layer die head extrudes curtain coating simultaneously, the two membranes that obtains after the extruding cast-sheet that just obtains stacked together just can obtain polyethylene film of the present invention again after biaxial tension; When the both side surface that obtains the polyethylene sandwich layer when needs all is attached with the polyethylene film of smooth superficial layer, can adopt three different extruders with raw materials melt (wherein, add polyethylene in the main extruder, all add smooth superficial layer raw material in the extruder of top layer), and molten product comprised that by same three layers die head extrudes curtain coating simultaneously, the trilamellar membrane that obtains after the extruding cast-sheet that obtains stacked together just can obtain polyethylene film of the present invention again after biaxial tension.
According to the present invention, described condition and the used extruder of extruding curtain coating is as well known to those skilled in the art.For example, can adopt single screw extrusion machine, double screw extruder etc.The condition of extruding generally includes extrusion temperature and curtain coating chilling temperature, and described extrusion temperature comprises extruder temperature, draping district temperature and head temperature, and described extrusion temperature can be 180-250 ℃; Described curtain coating chilling temperature refers generally to the temperature of casting roller, can be 10-95 ℃.
According to the present invention, described biaxial tension can be carried out in biaxial tension equipment, for example carries out biaxial tension in the model available from German Br ü ckner company is the film biaxial orientation stretching machine of Karo IV.Described biaxial tension can adopt synchronous method to stretch, and namely carries out film vertically (MD) and laterally (TD) stretching simultaneously; Also can adopt the method for fractional steps to stretch, namely carry out vertically (MD) stretching of film earlier, carry out laterally (TD) stretching of film then; Perhaps, carry out laterally (TD) stretching of film earlier, carry out vertically (MD) stretching of film then.Particularly, described synchronous method is stretched as: will extrude cast-sheet that curtain coating obtains at 80-140 ℃ down after the abundant preheating, and carry out the synchro-draw of MD and TD direction; Wherein, the MD stretching ratio can be 2-7 times, and the TD stretching ratio can be 2-7 times, and draft temperature can be 80-140 ℃.The described method of fractional steps is stretched as: will extrude cast-sheet that curtain coating obtains at 80-140 ℃ down after the abundant preheating, carry out the stretching of MD direction earlier, stretching ratio can be 2-7 doubly, draft temperature can be 80-140 ℃; And then after abundant preheating under 80-140 ℃, carry out the stretching of TD direction, and stretching ratio can be 2-7 times, draft temperature can be 80-140 ℃.
According to the present invention, the film that obtains can also be carried out annealing in process behind the described drawing and forming, produce bigger contraction with the film that prevents from obtaining; Film after perhaps directly will stretching carries out just can obtaining polyethylene film product of the present invention after cutting edge and the rolling.
According to the present invention, the selection of the thickness of the content of described self-lubricating particulate, the thickness of polyethylene sandwich layer, smooth superficial layer and the particle diameter of self-lubricating particulate is described hereinbefore, here repeats no more.
The used hot-air oven of embodiment and Comparative Examples is available from Beijing Jing Tong instrument plant, and model is DF205; The extruding pelletization device therefor is double screw extruder, and available from German WP company, model is ZSK25; Biaxial orientation stretching machine is available from German Br ü ckner company, and model is Karo IV; Extrude casting apparatus available from Sweden Labtech company, model is LCR400; Poly melt index is that the fusion index instrument of MP600 is measured by the model available from U.S. TO company.The polytetrafluoroethylene (PTFE) particulate is available from Su Wei group, and melt temperature is that 327-333 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.04 and 0.04; Medlin particulate is available from Hubei bismaleimide resin factory, and melt temperature is that 330-350 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.06 and 0.06; Polyamide particles can be available from the Guangzhou Long Suliaocailiaochang that escapes, and melt temperature can be respectively 0.42 and 0.35 for 255-265 ℃, confficient of static friction and the coefficient of kinetic friction; Described polyether-ether-ketone particulate is available from Britain Wei Gesi company, and melt temperature is that 334-340 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.2 and 0.2; The erucyl amide particulate is available from Britain standing grain major company, and melt temperature is that 79-81 ℃, confficient of static friction and the coefficient of kinetic friction are respectively 0.06 and 0.06.
Embodiment 1
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Among this embodiment, form the polyethylene of polyethylene sandwich layer and smooth superficial layer available from Exxon Mobil Corporation, the melt index under 190 ℃, 2.16kg is that 1 gram/10 minutes, melt temperature are 128 ℃.
(1) preparation of smooth superficial layer raw material:
Polyethylene is carried out drying in hot-air oven, wherein, dry mode purged 8 hours continuously for the heated drying air with 80 ℃.The polytetrafluoroethylene (PTFE) particulate (particle diameter is the 1-2 micron) of the dried polyethylene of the process of 99.5 weight portions and 0.5 weight portion joined in the mixer under 25 ℃, stir, mixer is earlier with about 7 minutes of 100 rev/mins of mixed on low speed, and then with 200 rev/mins of high-speed mixing 8 minutes;
The above-mentioned mixture that stirs is sent in the double screw extruder.Adjust the rotating speed to 350 rev/min of screw rod, each zone temperatures is controlled respectively: 190 ℃, 200 ℃, 210 ℃, 210 ℃, 210 ℃ and 210 ℃; The vacuum of each section remains 0.02 to 0.09 MPa; Mixture after fusion, shearing, dispersion, compression, exhaust, plastifying, extrude, is extruded, after the pelletizing of tie rod water-cooled, is finally obtained smooth superficial layer raw material through 210 ℃ of die heads again in the screw rod and cylindrical shell of above-mentioned extruder.
(2) preparation of cast-sheet:
The smooth superficial layer raw material that polyethylene and step (1) are obtained carries out drying respectively in hot-air oven, wherein, dry mode is for 80 ℃ heated drying air purging 8 hours continuously.Dried polyethylene adding is extruded in the main extruder of casting apparatus, the smooth superficial layer raw material adding that step (1) obtains is extruded in the top layer extruder of casting apparatus, melt extrude, and through the casting roller flow casting molding, obtaining skin depth is 35 microns, and core layer thickness is 350 microns raw material sheet material.Wherein, the temperature of two extruders is set consistent, and each zone temperatures of extruder is respectively 210 ℃, 220 ℃, 230 ℃, 230 ℃, 230 ℃, and draping district temperature is 240 ℃, and head temperature is 235 ℃, and the casting roller temperature is 25 ℃.
(3) biaxial tension moulding:
The raw material sheet material that step (2) is obtained carries out biaxial tension with biaxial orientation stretching machine.Used stretching mode stretches for carrying out carrying out TD after MD stretches earlier, and wherein, the preheat temperature that MD stretches is that 110 ℃, draft temperature are that 100 ℃, stretching ratio are 5 times; The preheat temperature that TD stretches is that 110 ℃, draft temperature are that 100 ℃, stretching ratio are 7 times.Formation comprises the polyethylene film X1 of polyethylene sandwich layer and the smooth superficial layer of a side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 10 microns, and the thickness of smooth superficial layer is 1 micron.
Embodiment 2
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Among this embodiment, form the polyethylene of polyethylene sandwich layer and smooth superficial layer available from Maoming petrochemical industry, the melt index under 190 ℃, 2.16kg is that 2 grams/10 minutes, melt temperature are 123 ℃.
(1) preparation of smooth superficial layer raw material:
Polyethylene is carried out drying in hot-air oven, wherein, dry mode purged 8 hours continuously for the heated drying air with 80 ℃.With the polytetrafluoroethylene (PTFE) particulate (particle diameter is the 2-4 micron) of the dried polyethylene of the process of 97 weight portions and 3 weight portions add mixer under 25 ℃, stir, mixer is earlier with about 5 minutes of 80 rev/mins of mixed on low speed, and then with 15 rev/mins of high-speed mixing 6 minutes;
The above-mentioned mixture that stirs is sent in the double screw extruder.Adjust the rotating speed to 350 rev/min of screw rod, each zone temperatures is controlled respectively: 190 ℃, 200 ℃, 210 ℃, 210 ℃, 210 ℃ and 210 ℃; The vacuum of each section remains 0.02 to 0.09 MPa; Mixture after fusion, shearing, dispersion, compression, exhaust, plastifying, extrude, is extruded, after the pelletizing of tie rod water-cooled, is finally obtained smooth superficial layer raw material through 210 ℃ of die heads again in the screw rod and cylindrical shell of above-mentioned extruder.
(2) preparation of cast-sheet:
The smooth superficial layer raw material that polyethylene and step (1) are obtained carries out drying respectively in hot-air oven, wherein, dry mode is for 80 ℃ heated drying air purging 8 hours continuously.Dried polyethylene adding is extruded in the main extruder of casting apparatus, the smooth superficial layer raw material adding that step (1) obtains is extruded in the top layer extruder of casting apparatus, melt extrude, and through the casting roller flow casting molding, obtaining skin depth is 70 microns, and core layer thickness is 875 microns raw material sheet material.Wherein, the temperature of two extruders is set consistent, and each zone temperatures of extruder is respectively 210 ℃, 220 ℃, 230 ℃, 230 ℃, 230 ℃, and draping district temperature is 240 ℃, and head temperature is 235 ℃, and the casting roller temperature is 35 ℃.
(3) biaxial tension moulding:
The raw material sheet material that step (2) is obtained carries out biaxial tension with biaxial orientation stretching machine.Used stretching mode is for carrying out film vertically (MD) and laterally (TD) stretching simultaneously, and wherein, the preheat temperature during stretching is that 110 ℃, draft temperature are 100 ℃, and the MD stretching ratio is 5 times, and the TD stretching ratio is 7 times.Formation comprises the polyethylene film X2 of polyethylene sandwich layer and the smooth superficial layer of a side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 25 microns, and the thickness of smooth superficial layer is 2 microns.
Embodiment 3
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Among this embodiment, form the polyethylene of polyethylene sandwich layer and smooth superficial layer available from Exxon Mobil Corporation, the melt index under 190 ℃, 2.16kg is that 3.5 grams/10 minutes, melt temperature are 118 ℃.
(1) preparation of smooth superficial layer raw material:
Polyethylene is carried out drying in hot-air oven, wherein, dry mode purged 8 hours continuously for the heated drying air with 80 ℃.The polyether-ether-ketone particulate (particle diameter is the 3-6 micron) of the dried polyethylene of the process of 98.5 weight portions and 1.5 weight portions joined in the mixer under 25 ℃, stir, mixer is earlier with about 5 minutes of 80 rev/mins of mixed on low speed, and then with 15 rev/mins of high-speed mixing 6 minutes;
The above-mentioned mixture that stirs is sent in the double screw extruder.Adjust the rotating speed to 350 rev/min of screw rod, each zone temperatures is controlled respectively: 190 ℃, 200 ℃, 210 ℃, 210 ℃, 210 ℃ and 210 ℃; The vacuum of each section remains 0.02 to 0.09 MPa; Mixture after fusion, shearing, dispersion, compression, exhaust, plastifying, extrude, is extruded, after the pelletizing of tie rod water-cooled, is finally obtained smooth superficial layer raw material through 210 ℃ of die heads again in the screw rod and cylindrical shell of above-mentioned extruder.
(2) preparation of cast-sheet:
The smooth superficial layer raw material that polyethylene and step (1) are obtained carries out drying respectively in hot-air oven, wherein, dry mode is for 80 ℃ heated drying air purging 8 hours continuously.Dried polyethylene adding is extruded in the main extruder of casting apparatus, the smooth superficial layer raw material adding that step (1) obtains is extruded in the upper and lower top layer extruder of casting apparatus, melt extrude, and through the casting roller flow casting molding, obtain skin depth and be 105 microns, core layer thickness is 1400 microns raw material sheet material.Wherein, the temperature of three extruders is set consistent, and each zone temperatures of extruder is respectively 210 ℃, 220 ℃, 230 ℃, 230 ℃, 230 ℃, and draping district temperature is 240 ℃, and head temperature is 235 ℃, and the casting roller temperature is 25 ℃.
(3) biaxial tension moulding:
The raw material sheet material that step (2) is obtained carries out biaxial tension with biaxial orientation stretching machine.Used stretching mode stretches for carrying out carrying out TD after MD stretches earlier, and wherein, the preheat temperature that MD stretches is that 110 ℃, draft temperature are that 100 ℃, stretching ratio are 5 times; The preheat temperature that TD stretches is that 110 ℃, draft temperature are that 100 ℃, stretching ratio are 7 times.Formation comprises the polyethylene film X3 of polyethylene sandwich layer and the smooth superficial layer of the both side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 40 microns, and the thickness of two-layer smooth superficial layer is 3 microns.
Embodiment 4
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Method according to embodiment 3 prepares polyethylene film, and different is that described polyether-ether-ketone particulate substitutes with medlin particulate (particle diameter is the 3-6 micron).Formation comprises the polyethylene film X4 of polyethylene sandwich layer and the smooth superficial layer of the both side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 40 microns, and the thickness of two-layer smooth superficial layer is 3 microns.
Embodiment 5
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Method according to embodiment 2 prepares polyethylene film, and different is that described polytetrafluoroethylene (PTFE) particulate substitutes with polyamide particles (particle diameter is the 2-4 micron).Formation comprises the polyethylene film X5 of polyethylene sandwich layer and the smooth superficial layer of a side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 25 microns, and the thickness of smooth superficial layer is 2 microns.
Embodiment 6
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Method according to embodiment 3 prepares polyethylene film, different is, described self-lubricating particulate polyether-ether-ketone particulate is with the mixture replacing of medlin particulate (particle diameter is the 3-6 micron) and polytetrafluoroethylene (PTFE) particulate (particle diameter is the 3-6 micron), wherein, the weight ratio of described medlin particulate and polytetrafluoroethylene (PTFE) particulate is 1: 1.Formation comprises the polyethylene film X6 of polyethylene sandwich layer and the smooth superficial layer of the both side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 40 microns, and the thickness of two-layer smooth superficial layer is 3 microns.
Embodiment 7
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Method according to embodiment 2 prepares polyethylene film, and different is, in the preparation process of smooth superficial layer raw material, described poly addition is 90 weight portions, and the addition of described polytetrafluoroethylene (PTFE) particulate is 10 weight portions.Formation comprises the polyethylene film X7 of polyethylene sandwich layer and the smooth superficial layer of a side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 25 microns, and the thickness of smooth superficial layer is 2 microns.
Embodiment 8
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Method according to embodiment 2 prepares polyethylene film, and different is, in the preparation process of smooth superficial layer raw material, described poly addition is 88 weight portions, and the addition of described polytetrafluoroethylene (PTFE) particulate is 12 weight portions.Formation comprises the polyethylene film X8 of polyethylene sandwich layer and the smooth superficial layer of a side surface that is attached to described polyethylene sandwich layer, and wherein, the thickness of polyethylene sandwich layer is 25 microns, and the thickness of smooth superficial layer is 2 microns.
Embodiment 9
This embodiment is used for the preparation of explanation polyethylene film provided by the invention.
Method according to embodiment 2 prepares polyethylene film, different is, is 2 times by MD stretching ratio in the control step (3), and the TD stretching ratio is 3.5 times, the thickness of the polyethylene sandwich layer of the polyethylene film X9 that obtains is 10 microns, and the thickness of smooth superficial layer is 125 microns.
Comparative Examples 1
This Comparative Examples is used for the reference preparation of explanation polyethylene film.
Mode according to embodiment 1 prepares polyethylene film, different is, this Comparative Examples does not comprise the step of the preparation of smooth superficial layer raw material, but polyethylene and polytetrafluoroethylene (PTFE) particulate directly mixed and send in the casting machine extrudate flow and delay biaxial tension, obtain the polyethylene film of individual layer, be specially:
(1) preparation of cast-sheet:
The mixture of the polyethylene among the embodiment 1 and polytetrafluoroethylene (PTFE) particulate is carried out drying in hot-air oven, wherein, dry mode purged 8 hours continuously for the heated drying air with 80 ℃.Dried described mixture added extrude in the same extruder of casting apparatus, melt extrude, and through the casting roller flow casting molding, obtain thickness and be 700 microns raw material sheet material.Wherein, each zone temperatures of extruder is respectively 210 ℃, 220 ℃, 230 ℃, 230 ℃, 230 ℃, and draping district temperature is 240 ℃, and head temperature is 235 ℃, and the casting roller temperature is 25 ℃.
(2) biaxial tension moulding:
The raw material sheet material that step (1) is obtained carries out biaxial tension with biaxial orientation stretching machine.Used stretching mode stretches for carrying out carrying out TD after MD stretches earlier, and wherein, the preheat temperature that MD stretches is that 110 ℃, draft temperature are that 100 ℃, stretching ratio are 5 times; The preheat temperature that TD stretches is that 110 ℃, draft temperature are that 100 ℃, stretching ratio are 7 times.Formation contains the polyethylene film D1 of the individual layer of self-lubricating particulate, and wherein, the thickness of described polyethylene film is 11 microns.
Comparative Examples 2
This Comparative Examples is used for the reference preparation of explanation polyethylene film.
Method according to Comparative Examples 1 prepares polyethylene film, and different is, does not add the polytetrafluoroethylene (PTFE) particulate when preparing described polyethylene film, forms the polyethylene film D2 of the individual layer that does not contain the self-lubricating particulate.Wherein, the thickness of described polyethylene film is 11 microns.
Comparative Examples 3
This Comparative Examples is used for the reference preparation of explanation polyethylene film.
Method according to Comparative Examples 1 prepares polyethylene film, and different is that described polytetrafluoroethylene (PTFE) particulate substitutes with the erucyl amide particulate, forms polyethylene film D3.Wherein, the thickness of described polyethylene film is 11 microns.
Comparative Examples 4
This Comparative Examples is used for the reference preparation of explanation polyethylene film.
Method according to embodiment 5 prepares polyethylene film, and different is that described polyamide particles substitutes with silicon dioxide microparticle (particle diameter is the 2-4 micron), forms polyethylene film D4.Wherein, the thickness of polyethylene sandwich layer is 25 microns, and the thickness of smooth superficial layer is 2 microns.
Test case 1-9
Test case 1-9 is used for the test of explanation polyethylene film performance.
(1) test of smooth performance:
The smooth performance test of film is used the PPT-F1 type friction coefficient instrument test of Jinan blue streak company according to the method for GB/T10006.The gained result is as shown in table 1.
(2) test of mist degree and glossiness:
Film mist degree test is according to the method for GB/T2410, uses the A-4725 type transmission mist shadow analyzer test of German BYK company; Film glossiness test is according to the method for ASTMD2457-08, uses the A-4454 type glossiness tester test of German BYK company.The gained result is as shown in table 1.
(3) test of mechanical property:
Thin film mechanical performance test is according to the method for GB/T1040.3-2006, uses the Z020 type cupping machine test of German Zwick company.The gained result is as shown in table 1.
Contrast test example 1-4
Contrast test example 1-4 is used for the test of explanation reference polyethylene film.
Method according to test case 1-9 is tested the performance of polyethylene film, and different is that described polyethylene film is respectively the polyethylene film D1-D4 that Comparative Examples 1-4 makes.The gained result is as shown in table 1.
From the result of table 1 as can be seen, the polyethylene film that adopts method provided by the invention to prepare has excellent smooth performance, and Film Optics performance and mechanical property are all better.
Claims (13)
1. a polyethylene film is characterized in that, described film comprises the polyethylene sandwich layer and be attached to the smooth superficial layer of at least one side surface of described polyethylene sandwich layer that described smooth superficial layer is the polyethylene layer that is dispersed with the self-lubricating particulate; Polyethylene in described polyethylene sandwich layer and the smooth superficial layer is 0.5g/10min-5g/10min at 190 ℃, the melt index of 2.16kg, is preferably 1g/10min-3.5g/10min; Described self-lubricating particulate be melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle.
2. polyethylene film according to claim 1, wherein, described high molecular particle is selected from one or more in polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and the polyether-ether-ketone particulate.
3. polyethylene film according to claim 1 and 2 wherein, is benchmark with the gross mass of described smooth superficial layer, and the content of described self-lubricating particulate is 0.05-10 weight %, is preferably 0.5-3 weight %.
4. polyethylene film according to claim 1 and 2, wherein, the thickness of described polyethylene sandwich layer is the 5-100 micron, and the thickness of the smooth superficial layer of described polyethylene sandwich layer one side is the 0.1-10 micron, and the particle diameter of described self-lubricating particulate is the 0.1-20 micron; Preferably, the thickness of described polyethylene sandwich layer is the 10-40 micron, and the thickness of the smooth superficial layer of described polyethylene sandwich layer one side is the 1-3 micron, and the particle diameter of described self-lubricating particulate is the 1-6 micron.
5. polyethylene film according to claim 4, wherein, the particle diameter of described self-lubricating particulate is the 100%-200% of thickness of the smooth superficial layer of described polyethylene sandwich layer one side.
6. polyethylene film according to claim 1, wherein, the polyethylene melt temperature in described polyethylene sandwich layer and the smooth superficial layer is 110-132 ℃.
7. the preparation method of a polyethylene film is characterized in that, this method comprises sends into melting mixing and extruding pelletization in the extruder after polyethylene and self-lubricating particulate mixed, and obtains smooth superficial layer raw material; Described smooth superficial layer raw material and polyethylene sent into have extruding of multi-layer co-extruded structure and extrude curtain coating in the casting apparatus, obtain the cast-sheet of the smooth superficial layer of at least one side surface of comprising the polyethylene sandwich layer and being attached to described polyethylene sandwich layer; And the cast-sheet that obtains carried out biaxial tension, obtain the Biaxially-oriented polyethylene film of the smooth superficial layer of at least one side surface of comprising the polyethylene sandwich layer and being attached to described polyethylene sandwich layer; Described smooth superficial layer is the polyethylene layer that is dispersed with the self-lubricating particulate; Polyethylene in described polyethylene sandwich layer and the smooth superficial layer is 0.5g/10min-5g/10min at 190 ℃, the melt index of 2.16kg, is preferably 1g/10min-3.5g/10min; Described self-lubricating particulate be melt temperature more than or equal to 250 ℃, confficient of static friction and the coefficient of kinetic friction all are less than or equal to 0.6 high molecular particle.
8. method according to claim 7, wherein, described high molecular particle is selected from one or more in polytetrafluoroethylene (PTFE) particulate, medlin particulate, polyamide particles and the polyether-ether-ketone particulate.
9. according to claim 7 or 8 described methods, wherein, the feasible gross mass with the smooth superficial layer of described polyethylene of the consumption of described self-lubricating particulate is benchmark, and the content of self-lubricating particulate is 0.05-10 weight %, is preferably 0.5-3 weight %.
10. according to claim 7 or 8 described methods, wherein, the consumption of described polyethylene and self-lubricating particulate and biaxial tension condition make that the thickness of described polyethylene sandwich layer is the 5-100 micron, and the thickness of the smooth superficial layer of described polyethylene sandwich layer one side is the 0.1-10 micron; Preferably, the consumption of described polyethylene and self-lubricating particulate and biaxial tension condition make that the thickness of described polyethylene sandwich layer is the 10-40 micron, and the thickness of the smooth superficial layer of described polyethylene sandwich layer one side is the 1-3 micron.
11. method according to claim 10, wherein, the particle diameter of described self-lubricating particulate is the 100%-200% of thickness of the smooth superficial layer of described polyethylene sandwich layer one side.
12. method according to claim 7, wherein, the cross directional stretch multiplying power of described biaxial tension is 2-7 times, and the longitudinal stretching multiplying power is 2-7 times.
13. one kind by any polyethylene film that described method prepares among the claim 7-12.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109705424A (en) * | 2017-10-26 | 2019-05-03 | 中国石油化工股份有限公司 | A kind of Biaxially-oriented polyethylene antibacterial film and preparation method thereof |
| CN113580707A (en) * | 2021-08-04 | 2021-11-02 | 厦门欧美盛塑化有限公司 | TPE film, TPE gloves and preparation method thereof |
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| CN101475074A (en) * | 2009-01-22 | 2009-07-08 | 黄山永佳（集团）有限公司 | Self-lubricating polyethylene membrane |
| CN102173156A (en) * | 2011-03-11 | 2011-09-07 | 佛山塑料集团股份有限公司 | Biaxial tension polyethylene film and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101475074A (en) * | 2009-01-22 | 2009-07-08 | 黄山永佳（集团）有限公司 | Self-lubricating polyethylene membrane |
| CN102173156A (en) * | 2011-03-11 | 2011-09-07 | 佛山塑料集团股份有限公司 | Biaxial tension polyethylene film and preparation method thereof |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109705424A (en) * | 2017-10-26 | 2019-05-03 | 中国石油化工股份有限公司 | A kind of Biaxially-oriented polyethylene antibacterial film and preparation method thereof |
| CN109705424B (en) * | 2017-10-26 | 2021-11-19 | 中国石油化工股份有限公司 | Biaxially oriented polyethylene antibacterial film and preparation method thereof |
| CN113580707A (en) * | 2021-08-04 | 2021-11-02 | 厦门欧美盛塑化有限公司 | TPE film, TPE gloves and preparation method thereof |
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