CN110982158A

CN110982158A - Film and method for producing same

Info

Publication number: CN110982158A
Application number: CN201911010084.6A
Authority: CN
Inventors: 李玉裕
Original assignee: Jiangyin City Dehui Heat Shrinkable Packing Materials Co ltd
Current assignee: Jiangyin City Dehui Heat Shrinkable Packing Materials Co ltd
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2020-04-10
Also published as: ZA202204143B; WO2021077466A1

Abstract

The invention discloses a method for preparing a film and a film prepared by the method. The method comprises the following steps: mixing nano titanium dioxide with water to obtain a first solution; heating the first mixture to about 80 ℃ to 160 ℃; adding the first solution to the heated first mixture at about 80 ℃ to 160 ℃ to obtain a second mixture; and subjecting the second mixture to multilayer co-extrusion, film blowing or casting to obtain the film.

Description

Film and method for producing same

FIELD

The disclosure relates to the technical field of films, in particular to a common antifogging antibacterial film and a multilayer composite high-barrier antifogging antibacterial film.

Background

Plastic films are constantly being developed and innovated to accommodate the ever-increasing packaging needs. The traditional package focuses on the delicacy of the appearance of the package, the modern package develops towards functional package, a new target of intelligent package is provided, the package requirements of vegetables, fruits, grains and food are higher, and the requirements of modern people on food preservation and quality guarantee and food safety are higher and higher.

The existing packaging film comprises a single-layer film, a composite film and a co-extrusion film, and the packaging modes comprise modified atmosphere packaging, inflation packaging and vacuum packaging, so that the effects of dewatering, oxygen resistance and corrosion prevention are achieved to a certain extent, but the existing packaging film still has weak functions and cannot meet the packaging requirements of food preservation and quality guarantee. During the storage, transportation and sale of vegetables and fruits, a large amount of water vapor can be volatilized and condensed to the inner surface of a packing material to form water vapor and water drops, and then the water vapor and the water drops flow to the vegetables and fruits to cause the vegetables and fruits to be rotted at an accelerated speed, so that the bacteria breeding is increased, the water is greatly lost, a large amount of rotting and deterioration are caused, the environment is polluted, and the waste is great. Rice and other grains are gradually mildewed after being packaged. Food products generally do not meet the shelf life requirements. Therefore, the market urgently needs a packaging product with stronger fresh-keeping and quality-guaranteeing functions.

The existing antibacterial film in domestic and international markets is prepared by using an inorganic silver antibacterial agent. The antibacterial agent was invented by western european scientists more than 10 years ago and was introduced in recent years. Is an effective antibacterial film which is recognized at present. However, the antibacterial effect of the antibacterial film is still in a large difference, the use requirement of people is not met, the key is that the film uses nano silver as the antibacterial agent, and no data at present proves that the film has no toxic or side effect on human bodies. At present, the film is mainly used for textiles such as deodorant socks and the like, and has no wide application in the field of food packaging.

Therefore, a packaging film which integrates barrier, antifogging and antibacterial functions and has high-efficiency fresh-keeping and quality-guaranteeing capacity is needed.

SUMMARY

In one aspect, the present disclosure relates to a method of making a membrane comprising:

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to about 80 ℃ to 160 ℃;

adding the first solution to the heated first mixture at about 80 ℃ to 160 ℃ to obtain a second mixture; and

the second mixture is coextruded, blown film or cast to obtain the film.

In another aspect, the present disclosure relates to a membrane prepared by a process comprising the steps of:

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to about 80 ℃ to 160 ℃;

the second mixture is coextruded, blown film or cast to obtain the film.

In another aspect, the present disclosure relates to a multilayer film comprising an inner layer, a secondary inner layer, a middle layer, and an outer layer, wherein the inner layer is prepared by a process comprising the steps of:

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to about 80 ℃ to 160 ℃;

the second mixture is coextruded, blown film or cast to obtain the film.

Brief description of the drawings

Fig. 1 shows a schematic view of a multilayer anti-fog anti-bacterial film according to an embodiment of the present disclosure;

fig. 2 shows a schematic view of a multilayer anti-fog anti-bacterial film according to another embodiment of the present disclosure.

Detailed description of the invention

In the following description, certain specific details are included to provide a thorough understanding of various disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth.

Unless otherwise required by the disclosure, throughout the specification and the appended claims, the words "comprise", "comprising", and "have" are to be construed in an open, inclusive sense, i.e., "including but not limited to".

Reference throughout the specification to "one embodiment," "an embodiment," "in another embodiment," or "in certain embodiments" means that a particular reference element, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" or "in another embodiment" or "in certain embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment, and furthermore, particular elements, structures, or features may be combined in any suitable manner in one or more embodiments.

Definition of

In the present disclosure, the term "plastic particles" is a common name for plastic granules, which are raw materials for storing, transporting and processing plastic in a semi-finished form.

In the present disclosure, the term "antifogging surfactant" refers to a low molecular weight dispersant containing hydrophilic and lipophilic groups, and the antifogging agent with strong hydrophilicity and lipophilic chain length has good compatibility with plastics, slow migration speed and good lasting demisting effect.

In the present disclosure, the term "antimicrobial agent" refers to a class of agents used to prevent various types of bacteria from causing decay in vegetables, fruits, and foods.

In the present disclosure, the term "LDPE" refers to low density polyethylene, typically a polymer obtained by polymerization of ethylene as monomer, using oxygen or an organic peroxide as initiator, at a high pressure of 98.0 to 294 MPa.

In the present disclosure, the term "LLDPE" refers to a linear low density polyethylene that is structurally different from a general low density polyethylene because of the absence of long chain branches.

In the present disclosure, the term "EVA" refers to an ethylene-vinyl acetate copolymer, which is a copolymer of ethylene and acetic acid.

In the present disclosure, the term "metallocene" refers to an organometallic complex compound formed by linking a transition metal to cyclopentadiene.

In the present disclosure, the term "erucamide" is an important derivative of erucic acid, an excellent fine chemical product with a wide range of applications. It is mainly used as anti-sticking agent and slip agent for various plastics and resins, excellent lubricant and antistatic agent for extruded film, because of its higher melting point and good thermal stability (stability at 273 deg.C).

In the present disclosure, the term "PE" refers to polyethylene, which is a typical thermoplastic material with good flexibility and water vapor permeability, and can be subdivided into LDPE, LLDPE and HDPE.

In the present disclosure, the term "PP" refers to polypropylene, which is a semi-crystalline thermoplastic.

In the present disclosure, the term "PA" refers to polyamide, commonly known as nylon, which is a polar polymer having good mechanical properties, barrier properties and printing properties.

In the present disclosure, the term "EVOH" refers to an ethylene-vinyl alcohol copolymer, which is an alcoholysis product of saponification of an ethylene-vinyl acetate copolymer, is highly crystalline, has good mechanical strength, elastic modulus and excellent oxygen barrier property, and is called a triple high barrier material together with polyvinylidene chloride (PVDC) and polypropylene cyanide.

In the present disclosure, the term "Pia" refers to a polyimide gum, and polyimide refers to a class of polymers having imide rings (-CO-NH-CO-) in the main chain, of which polymers having a phthalimide structure are most important.

In the present disclosure, the term "antistatic agent" is a class of additives that are added to plastics or applied to the surface of molded articles for the purpose of reducing static buildup.

In the present disclosure, the term "drip-off agent" is a surfactant that acts as a type of adjuvant that breaks the interfacial tension between the water droplets and the film, preventing the formation of water droplets on the surface.

Detailed Description

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to about 80 ℃ to 120 ℃;

adding the first solution to the heated first mixture at about 80 ℃ to 120 ℃ to obtain a second mixture; and

the second mixture is coextruded, blown film or cast to obtain the film.

In certain embodiments, the first mixture is selected from the group consisting of an anti-fog surfactant-containing masterbatch, Low Density Polyethylene (LDPE), linear low density polyethylene (LLPPE), polypropylene (PP), Ethylene Vinyl Acetate (EVA), an adjuvant, or mixtures thereof.

In certain embodiments, the second mixture is also subjected to a temperature increase and cooling step prior to film formation.

In certain embodiments, the antifogging surfactant-containing masterbatch comprises, in weight percent, about 1 to 20 parts, about 20 to 60 parts, Low Density Polyethylene (LDPE), about 30 to 80 parts, linear low density polyethylene (ppe), about 1 to 10 parts, Ethylene Vinyl Acetate (EVA), and about 0 to 30 parts, an adjuvant.

In certain embodiments, the antifogging surfactant-containing masterbatch comprises, in weight percent, about 1 to 20 parts, about 50 to 140 parts, polypropylene (PP), about 1 to 10 parts, Ethylene Vinyl Acetate (EVA), and about 0 to 30 parts of an adjuvant.

In certain embodiments, the base material, the anti-fog surfactant, and the auxiliary material are mixed and granulated to obtain the master batch containing the anti-fog surfactant.

In certain embodiments, illustrative examples of base stocks that can be used in the present disclosure include, but are not limited to, mixtures of LDPE and LLDPE and mixtures of PP, LDPE and LLDPE,

in certain embodiments, the binder comprises about 60% to 80% by weight of the antifogging surfactant-containing masterbatch.

In certain embodiments, illustrative examples of anti-fog surfactants that can be used in the present disclosure include, but are not limited to, surfactants that include a hydrophilic group and a lipophilic group.

In certain embodiments, illustrative examples of hydrophilic groups that can be used in the present disclosure include, but are not limited to, carboxyl groups, hydroxyl groups, amine groups, and ether groups.

In certain embodiments, illustrative examples of lipophilic groups that can be used in the present disclosure include, but are not limited to, long chain alkyl groups and fluorocarbon chains.

In certain embodiments, the anti-fog surfactants that can be used in the present disclosure include at least one hydrocarbon surfactant and at least one fluorosurfactant.

In certain embodiments, illustrative examples of hydrocarbon surfactants that can be used in the present disclosure include, but are not limited to, fatty acid polyoxyethyleneamines, polyol fatty acid esters, ethanolamines, ricinoleic polyols, and polyether surfactants.

In certain embodiments, illustrative examples of hydrocarbon surfactants that can be used in the present disclosure include, but are not limited to, isomeric alcohol ethoxylates.

In certain embodiments, illustrative examples of fluorosurfactants that can be used in the present disclosure include, but are not limited to, amphoteric surfactants, fluorocarbon cationic surfactants, and nonionic fluorocarbon surfactants.

In certain embodiments, illustrative examples of amphoteric surfactants that can be used in the present disclosure include, but are not limited to, perfluoroalkyl theophyllines.

In certain embodiments, illustrative examples of nonionic fluorocarbon surfactants that can be used in the present disclosure include, but are not limited to, perfluoroalkyl phosphates, N-perfluoroalkyl sulfopropyltriethylsilane, and perfluoroalkyl poly.

In certain embodiments, illustrative examples of fluorocarbon cationic surfactants that can be used in the present disclosure include, but are not limited to, fluorocarbon cationic surfactants.

In certain embodiments, illustrative examples of nonionic fluorocarbon surfactants that can be used in the present disclosure include, but are not limited to, perfluoroalkyl polyethers.

In certain embodiments, the anti-fog surfactant comprises from about 10% to 25% by weight of the anti-fog surfactant-containing masterbatch.

In certain embodiments, illustrative examples of adjuvants that can be used in the present disclosure include, but are not limited to, water-absorbent resins, drip-on agents, and fillers.

In certain embodiments, illustrative examples of drip agents that can be used in the present disclosure include, but are not limited to, polyglyceryl fatty acid esters, polyglycerols, synthetic polyglycerols, and glyceryl monostearate.

In certain embodiments, illustrative examples of water-absorbent resins that can be used in the present disclosure include, but are not limited to, PVA and EVA.

In certain embodiments, illustrative examples of fillers that can be used in the present disclosure include, but are not limited to, diatomaceous earth, talc, and calcium carbonate.

In certain embodiments, illustrative examples of fillers that can be used in the present disclosure include, but are not limited to, diatomaceous earth.

In certain embodiments, the water-absorbent resin comprises about 5% to 10% by weight of the anti-fogging surfactant-containing master batch.

In certain embodiments, the extender comprises about 1% to about 10% by weight of the anti-fog surfactant-containing masterbatch.

In certain embodiments, the drip agent comprises about 0.5 to about 2% by weight of the concentrate comprising the anti-fog surfactant.

In certain embodiments, the granulation temperature is about 145 to 165 ℃.

In certain embodiments, illustrative examples of adjuvants that can be used in the present disclosure include, but are not limited to, metallocenes, artificial silica, erucamide, and antistatic agents.

In certain embodiments, the adjuvant comprises, by weight parts, about 0 to 10 parts of metallocene artificial silicon, about 0 to 10 parts of metallocene erucamide, and about 0 to 10 parts of metallocene antistatic agent.

In certain embodiments, illustrative examples of antistatic agents that can be used in the present disclosure include, but are not limited to, cationic antistatic agents, nonionic antistatic agents, and nonionic antistatic agents.

Illustrative examples of cationic antistatic agents that can be used in the present disclosure in certain embodiments include, but are not limited to, long chain alkyl quaternary ammonium, phosphorus, and phosphonium salts, with chloride as the counterion.

In certain embodiments, illustrative examples of anionic antistatic agents that can be used in the present disclosure include, but are not limited to, alkali metal salts of alkylsulfonic acids, phosphoric acids, and dithiocarbamic acids.

In certain embodiments, illustrative examples of nonionic antistatic agents that can be used in the present disclosure include, but are not limited to, ethoxylated fatty alkylamines.

In certain embodiments, the nano-titania that can be used in the present disclosure has a particle size of about 2 to 15 nm.

In certain embodiments, the nano-titania that can be used in the present disclosure has a particle size of about 2 to 10 nm.

In certain embodiments, the concentration of titanium dioxide in the first solution is about 1:20 to 1:10 parts by weight.

In certain embodiments, the concentration of titanium dioxide in the first solution is about 1:10 parts by weight.

In certain embodiments, the solid to liquid ratio of the first mixture to the first solution is about 1:0.6 to 1: 1.2.

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to about 80 ℃ to 160 ℃;

the second mixture is coextruded, blown film or cast to obtain the film.

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to about 80 ℃ to 160 ℃;

the second mixture is coextruded, blown film or cast to obtain the film.

In certain embodiments, the secondary inner layer is an antifog film.

In certain embodiments, the antifog film is made from a blend of LDPE and LLDPE or a masterbatch of PP, metallocene, EVA, and an antifog surfactant mixed, extruded, blown, or cast.

In certain embodiments, illustrative examples that can be used as a middle layer in the present disclosure include, but are not limited to, EVOH films and PA films.

In certain embodiments, the outer layer is made by blending, extruding, film blowing or casting a mixture of LDPE and LLDPE, metallocene, EVA, erucamide, antistatic agent.

In certain embodiments, an adhesive layer is disposed between the secondary inner layer and the middle layer.

In certain embodiments, an adhesive layer is disposed between the middle layer and the outer layer.

In certain embodiments, illustrative examples of tie layers that can be used in the present disclosure include, but are not limited to, high temperature resistant thermal conductive adhesives and pressure sensitive adhesives.

In certain embodiments, illustrative examples of high temperature resistant thermally conductive adhesives that can be used in the present disclosure include, but are not limited to, silicone-type high temperature resistant thermally conductive adhesives or polyimide adhesives (Pia).

In certain embodiments, illustrative examples of pressure sensitive adhesives that can be used in the present disclosure include, but are not limited to, polyacrylate based pressure sensitive adhesives.

In certain embodiments, the multilayer composite high-barrier anti-fog antibacterial film is five layers or seven layers or nine layers.

In certain embodiments, the multilayer film is an anti-fog, anti-bacterial multilayer film.

Hereinafter, the present disclosure will be explained in detail by the following examples in order to better understand various aspects of the present application and advantages thereof. It should be understood, however, that the following examples are not limiting and are merely illustrative of certain embodiments of the present disclosure.

Examples

Example 1

Mixing 7kg of a mixture of LDPE and LLDPE, 1.3kg of fluorocarbon cationic surfactant, perfluoroalkyl ether surfactant and polyoxyethylene ether surfactant, 0.2kg of PVA water-absorbent resin, 0.3kg of EVA water-absorbent resin, 0.5kg of diatomite, 0.5kg of talcum powder and 0.2kg of dripping agent, and granulating at 145 ℃ to obtain master batches containing the antifogging surfactant;

mixing 0.6kg of master batch containing an antifogging surfactant, 3kg of LDPE, 4kg of LLPPE, 0.5kg of EVA, 0.5kg of metallocene, 0.2kg of artificial silicon, 0.1kg of erucamide and 0.5kg of an antistatic agent to obtain a first mixture;

mixing 0.6kg of nano titanium dioxide with the particle size of 2-10nm and water according to the weight part of 1:10 to obtain a first solution; heating the first mixture to 100 ℃;

adding the first solution to the heated first mixture (adding amount or solid-to-liquid ratio) at 100 ℃ to obtain a second mixture, and heating the second mixture to 2 ℃; cooling the warmed second mixture; and co-extruding the cooled second mixture to blow a film, thereby obtaining the film.

Example 2

Mixing 6.4kg of a mixture of LDPE and LLDPE, 2.5kg of a mixture of perfluoroalkyl polyether surfactant and isomeric alcohol polyoxyethylene ether surfactant, 0.5kg of PVA water-absorbent resin, 0.5kg of talcum powder and 0.1kg of dripping agent, and granulating at 165 ℃ to obtain master batches containing the antifogging surfactant;

mixing 0.5kg of master batch containing an antifogging surfactant, 2.5kg of LDPE, 4.5kg of LLPPE, 0.6kg of EVA, 0.4kg of metallocene, 0.3kg of artificial silicon, 0.2kg of erucamide and 0.4kg of antistatic agent to obtain a first mixture;

mixing 0.6kg of nano titanium dioxide with the particle size of 5-15nm and water according to the weight part of 1:20 to obtain a first solution; heating the plastic raw material to 140 ℃;

adding the first solution to the heated first mixture at 140 ℃ to obtain a second mixture, and heating the second mixture to 3 ℃; cooling the warmed second mixture; and co-extruding and casting the cooled second mixture to obtain the film.

Example 3

Mixing 8kg of a mixture of LDPE and LLDPE, 1kg of a mixture of perfluoroalkyl polyether surfactant and isomeric alcohol polyoxyethylene ether surfactant, 0.5kg of a mixture of PVA water-absorbent resin and EVA water-absorbent resin, 0.45kg of calcium carbonate and 0.05 of drip agent, and granulating at 150 ℃ to obtain master batches containing the antifogging surfactant;

mixing master batch containing 0.7kg of antifogging surfactant, 2.5kg of LDPE, 4.3kg of LLPPE, 0.5kg of EVA, 0.5kg of metallocene, 0.2kg of artificial silicon, 0.1kg of erucamide and 0.5kg of antistatic agent to obtain a first mixture;

mixing 0.5kg of nano titanium dioxide with the particle size of 2-8nm and water according to the weight part of 1:15 to obtain a first solution;

heating the plastic raw material to 120 ℃; adding the first solution to the heated first mixture at 120 ℃ to obtain a second mixture, and heating the second mixture to 3 ℃; cooling the warmed second mixture; and co-extruding the cooled second mixture to blow a film, thereby obtaining the film.

Example 4

As shown in fig. 1, the seven-layer symmetrical structure anti-fog and anti-bacterial barrier film sequentially comprises from inside to outside: the inner layer 10, the secondary inner layer 20, the first glue layer 30, the middle layer 40, the second glue layer 50, the first outer layer 60 and the second outer layer 70, wherein the inner layer 10 is the film prepared in the embodiment 1, the first glue layer 30 and the second glue 50Pia glue, the middle layer 40 is an EVOH film, the secondary inner layer 20 is an antifogging film which is prepared by mixing, extruding and blowing a mixture of LDPE and LLDPE, metallocene, EVA and master batch containing an antifogging surfactant, and the first outer layer 60 and the second outer layer 70 are prepared by mixing, extruding and blowing a mixture of LDPE and LLDPE, metallocene, EVA, erucamide and an antistatic agent.

Example 5

As shown in fig. 2, the nine layers of barrier antifogging antibacterial films with symmetrical structures sequentially comprise from inside to outside: the inner layer 10 is the film prepared in the embodiment 1, the sub-inner layer 20 and the third inner layer 30 are prepared by mixing, extruding and blowing a mixture of LDPE and LLDPE, metallocene, EVA and master batches containing an antifogging surfactant, the first glue layer 40, the second glue layer 60Pia glue and the middle layer 50 are PA films, and the first outer layer 70, the second outer layer 80 and the third outer layer 90 are prepared by mixing, extruding and blowing a mixture of LDPE and LLDPE, metallocene, EVA, erucamide and an antistatic agent.

Performance testing

1. The antibacterial activity was tested according to the Japanese Industrial Standard JIS Z2801: 2010 antibacterial product-antibacterial test and antibacterial effect.

The sample was the multilayer film of example 4 and the control was a commercial conventional packaging cling film.

Sample pretreatment: wiping with 70% ethanol

Contact time: 24 +/-1 hour

The culture temperature is as follows: 35 +/-1 DEG C

Bacterial liquid concentration: 2.5-10X 10⁵cfu/mL

Inoculation amount: 1.0. + -. 0.1mL

Testing strains: staphylococcus aureus (ATCC 6538)

Escherichia coli (ATCC 8739)

Sample test amount: 1 piece/50X 50mm square piece

The test results are shown in table 1:

table 1 test data for antimicrobial activity of the multilayer film of example 4

Sample inoculation conditions are as follows: the samples were in sealed plastic bags

Sample preparation: submitted samples were washed as/and then tested

Determination of antibacterial effect:

the antibacterial effect value of the antibacterial processed product should be not less than 2.0.

As can be seen from Table 1, the antimicrobial activity of the multilayer film of the present disclosure against Staphylococcus aureus and Escherichia coli is 3 to 5.5, which is greater than 2.0 of JIS Z2801: 2010. And the recovery value of the bacteria in 0-24 hours is far smaller than that of the common preservative film sold on the market.

This is because the nano titanium oxide in the disclosed film forms electrons and holes under illumination and adsorbs O on the surface₂And H₂O acts to form superoxide radical, and positron combines with water molecule to produce hydroxyl radical, which has powerful oxidizing decomposition capacity and can decompose almost all organic compounds and partial inorganic matter into non-toxic carbon dioxide and water. The negative electrons and oxygen combine to form active oxygen, i.e. super oxide ion, which has strong oxidative decomposition capability and can destroy the cell membrane of bacteria and decompose bacteria simultaneouslyHarmful compound is released from the fungus bodies, so that the sterilization effect is realized.

2. The freshness time of the samples and the control samples was tested at room temperature or under refrigerated conditions. Wherein, the sample is the multilayer film of the example 4, and the comparison sample is a common packaging preservative film sold in the market.

The test results are shown in table 2:

table 2 experimental data for the multilayer film of example 4

As can be seen from table 2, the multi-layer film of the present disclosure has better preservation time or effect than the common preservative films on the market under both normal temperature and cold storage conditions.

The multilayer film disclosed by the invention realizes integration of barrier, antifogging and antibacterial functions, and effectively solves the problems of pain and difficulty in packaging vegetables, fruits and foods. The multilayer film has the characteristics of rapidness, high efficiency and lasting antifogging, and can efficiently prevent fogging under the conditions of refrigeration, conventional storage and transportation. In the storage period, fog and water are not generated in the packaging bag, the packaging bag is kept dry, the packaged material is well preserved, and the storage period is prolonged.

3. The antifogging performance of the sample was tested:

the antifogging properties of the plastic film were tested according to test standard GB/T31726-. Wherein the sample is the multilayer film of example 4.

The test results are shown in table 3:

table 3 experimental data for the multilayer film of example 4

As can be seen from table 3, the antifog performance, wet tension and moisture permeability of the multilayer film of the present disclosure are superior to national standards.

The high-fluorine efficient antifogging surfactant compounded by various excellent surfactants is adopted in the antifogging coating, the compounded surfactant migrates to the inner surface of the film, the surface tension of the film is enhanced, fog is rapidly diffused on the surface of the film to form a water film and be absorbed, the antifogging in normal temperature, cold and hot environments is realized, the better antifogging effect is achieved, and the antifogging effective period is prolonged. Meanwhile, the inner layer and the secondary inner layer are made of the anti-fog and anti-bacterial film, the anti-fog effect of the anti-fog surfactant of the inner layer can be gradually lost in the long-term use process of the anti-fog preservative film, and the anti-fog surfactant of the inner layer can be continuously transferred to the inner layer close to food from the secondary inner layer, so that the anti-fog surfactant of the inner layer can be continuously supplemented in time, and the lasting anti-fog effect of the preservative film is ensured.

4. And (3) detecting the agglomeration condition of the nano titanium dioxide in a sample, wherein the sample is the multilayer film of the example 4:

the method comprises the following steps: detecting the haze of the film;

detection standard: a high haze indicates more agglomeration, and a low haze indicates less agglomeration. If the haze reaches the standard or the transparency is high, no agglomeration or little agglomeration is indicated;

and (3) detection results: transparency value: and if the concentration is more than or equal to 90 percent, the agglomeration is low, the qualified level is reached, and the film of the sample is transparent and uniform.

The present disclosure uses photocatalyst nano titanium dioxide as an antibacterial agent, which is effectively mixed with plastic particles, extruded and blown into a film to prepare a packaging film. The adopted mixing technology can not cause the agglomeration and non-nanocrystallization of the nano titanium dioxide, and can also ensure that the nano titanium dioxide and plastic particles are uniformly mixed, improve the dispersion degree and the uniformity of the nano titanium dioxide in the film and improve the transparent plastic and antibacterial functions of the film. So that the nano titanium dioxide antibacterial film can realize industrialized production.

In the present disclosure, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

From the foregoing it will be appreciated that, although specific embodiments of the disclosure have been described herein for purposes of illustration, various modifications or improvements may be made by those skilled in the art without departing from the spirit and scope of the disclosure, and that such modifications or improvements are intended to be within the scope of the appended claims.

Claims

1. A method of making a membrane comprising:

mixing nano titanium dioxide with water to obtain a first solution;

heating the first mixture to 80 ℃ to 160 ℃;

adding the first solution to the heated first mixture at 80 ℃ to 160 ℃ to obtain a second mixture; and

the second mixture is coextruded, blown film or cast to obtain the film.

2. The method of claim 1, wherein the first mixture is selected from the group consisting of an anti-fog surfactant-containing masterbatch, Low Density Polyethylene (LDPE), linear low density polyethylene (LLPPE), polypropylene (PP), Ethylene Vinyl Acetate (EVA), an adjuvant, or mixtures thereof.

3. The method of claim 1, wherein the base stock, the anti-fog surfactant, and the auxiliary material are mixed and granulated to obtain the anti-fog surfactant containing masterbatch.

4. A process according to claim 3, wherein the binder is a mixture of LDPE and LLDPE or a mixture of PP, LDPE and LLDPE, preferably the binder comprises 60-80% by weight of the concentrate comprising the anti-fogging surfactant, preferably the anti-fogging surfactant comprises a hydrophilic group and a lipophilic group, preferably the hydrophilic group is selected from carboxyl, hydroxyl, amine or ether groups, preferably the lipophilic group is selected from long chain alkyl or fluorocarbon chains, preferably the anti-fogging surfactant comprises at least one hydrocarbon surfactant and at least one fluorine surfactant, more preferably the hydrocarbon surfactant is selected from fatty acid polyoxyethylene amines, polyol fatty acid esters, ethanolamines, ricinoleic polyol, polyether surfactants and mixtures thereof, even preferably the hydrocarbon surfactant is selected from isomeric alcohol polyoxyethylene ethers, preferably the fluorine surfactant is selected from amphoteric surfactants, Fluorocarbon cationic surfactant, nonionic fluorocarbon surfactant and their mixture, more preferably amphoteric surfactant is selected from perfluoroalkyl betaine, more preferably nonionic fluorocarbon surfactant is selected from perfluoroalkyl phosphate, N-perfluoroalkyl sulfopropyl triethylsilane, perfluoroalkyl poly and their mixture, more preferably fluorocarbon cationic surfactant is selected from fluorocarbon cationic surfactant, even more preferably nonionic fluorocarbon surfactant is selected from perfluoroalkyl polyether, preferably antifogging surfactant accounts for 10-25% of the mother granule containing antifogging surfactant by weight percentage, preferably the auxiliary material is selected from water absorbent resin, dripping agent, filling material and their mixture, preferably the water absorbent resin is selected from PVA, EVA and their mixture, the filling agent is selected from diatomaceous earth, talcum powder, calcium carbonate and their mixture, more preferably the filling agent is selected from diatomaceous earth, the water absorbing resin preferably accounts for 5-10% of the master batch containing the antifogging surfactant in percentage by weight, the filling agent preferably accounts for 1-10% of the master batch containing the antifogging surfactant in percentage by weight, the dripping agent preferably accounts for 0.5-2% of the master batch containing the antifogging surfactant in percentage by weight, and the granulation temperature is preferably 145-165 ℃.

5. The process of any one of claims 2 to 4 wherein the adjuvant is selected from metallocenes, artificial silica, erucamide, antistatic agents or mixtures thereof.

6. The process of any one of claims 1 to 5, wherein the nano titania has a particle size of 2 to 15nm, preferably the nano titania has a particle size of 2 to 10nm, preferably the concentration of titania in the first solution is 1:20 to 1:10 parts by weight, preferably 1:10 parts by weight.

7. A film produced by the method of any one of claims 1 to 6.

8. Multilayer film comprising an inner layer, a secondary inner layer, a middle layer and an outer layer, wherein the inner layer is the film of claim 7 or the film prepared by the process of any one of claims 1 to 6, preferably the secondary inner layer is an antifogging film, preferably the antifogging film is made from a blend of LDPE and LLDPE or a blend of PP, metallocene, EVA and masterbatch containing an antifogging surfactant, extruded, blown or cast, preferably the middle layer is selected from EVOH film or PA film, preferably the outer layer is made from a blend of LDPE and LLDPE, metallocene, EVA, erucamide, an antistatic agent, extruded, blown or cast.

9. The multilayer film according to claim 8, wherein the multilayer film further comprises an adhesive layer disposed between the secondary inner layer and the middle layer, preferably the multilayer film further comprises an adhesive layer disposed between the middle layer and the outer layer, preferably the adhesive layer is selected from a high temperature resistant thermally conductive adhesive or a pressure sensitive adhesive, preferably the high temperature resistant thermally conductive adhesive is a silicone type high temperature resistant thermally conductive adhesive or a polyimide adhesive (Pia), preferably the pressure sensitive adhesive is a polyacrylate type pressure sensitive adhesive, preferably the multilayer film is five or seven or nine layers.

10. The multilayer film of claim 8 or 9 which is an anti-fog, anti-bacterial multilayer film.