阅读说明：本技术 一种共挤出型柔感功能bopp薄膜和制备方法 (Co-extrusion type soft-feeling functional BOPP film and preparation method thereof ) 是由 杨东 于 2020-06-19 设计创作，主要内容包括：本发明公开了一种共挤出型柔感功能BOPP薄膜和制备方法,其特征在于所述包括芯层,其特征在于所述芯层的上方设置有柔感功能上表层,芯层的下方设置有防粘连下表层,所述柔感功能上表层的主体为改性聚氨酯弹性体,上表层的上端面设置有凹凸结构,柔感功能上表层含有膨胀微孔母料；本发明的有益效果是:使用改性热塑性弹性体TPE材料,通过一步挤出拉伸成型工艺,制备具有绒毛触感的柔感功能层产品,创造性地加入膨胀母料,拉伸过程中产生中空空穴和表面突起,表面获得微观中空凹凸球状形态,获得更为优越的绒毛丝滑触感柔感效果的性能,接触表面后挤压使中空微球有一定形变,且具有弹性向使用者反馈一定的回弹力,不易沾染指纹油污。(The invention discloses a co-extrusion type soft-feeling function BOPP film and a preparation method thereof, which are characterized by comprising a core layer, wherein a soft-feeling function upper surface layer is arranged above the core layer, an anti-adhesion lower surface layer is arranged below the core layer, the main body of the soft-feeling function upper surface layer is a modified polyurethane elastomer, the upper end surface of the upper surface layer is provided with a concave-convex structure, and the soft-feeling function upper surface layer contains an expansion micropore master batch; the invention has the beneficial effects that the modified thermoplastic elastomer TPE material is used for preparing the soft functional layer product with fluff touch through a one-step extrusion and stretching forming process, the expansion master batch is creatively added, hollow cavities and surface protrusions are generated in the stretching process, microscopic hollow concave-convex spherical shapes are obtained on the surface, the more excellent performance of the soft touch effect of the fluff silky touch is obtained, the hollow microspheres have certain deformation after being contacted with the surface and are extruded, the elasticity is realized, certain resilience is fed back to a user, and fingerprint oil stain is not easily polluted.)

1. The utility model provides a soft function BOPP film of coextrusion type, includes the sandwich layer, its characterized in that the top of sandwich layer is provided with soft function top layer, and the below of sandwich layer is provided with antiseized down top layer, the main part on soft function top layer is modified polyurethane elastomer, and the up end of top layer is provided with concave-convex structure.

2. The co-extruded soft-feel functional BOPP film according to claim 1, wherein the layer thickness of the soft-feel functional top surface layer is 2 to 3 um; the thickness of the core layer is 11-21 um; the thickness of the anti-adhesion lower surface layer is 1-1.5 um.

3. A preparation method of a co-extruded soft-feel BOPP film, wherein the co-extruded soft-feel BOPP film disclosed by claim 1 or 2 is prepared by the preparation method, and the preparation method comprises the following specific steps:

the soft-feeling functional upper surface layer comprises the following components in percentage by weight: modified polyurethane elastomer (TPE): 40 to 50 wt%; extinction master batch: 0 to 30 wt%; expanded microporous masterbatch: 20-60 wt%;

the core layer consists of the following components in percentage by weight: homo-polypropylene: 95-100 wt%; antistatic master batch: 0-5 wt%;

the anti-adhesion lower surface layer comprises the following components in percentage by weight: homo-polypropylene: 90-99 wt%; anti-adhesion master batch: 1 to 10 wt%.

4. The preparation method of the co-extrusion type soft-feeling BOPP film according to claim 3, wherein the soft-feeling functional upper surface layer, the core layer and the anti-adhesion lower surface layer are prepared by one-time co-extrusion, and specifically comprises the following steps:

firstly, premixing selected raw materials according to formula design requirements in sequence, putting the premixed raw materials into a corresponding extruder feeding system, and conveying the premixed raw materials to a corresponding extruder after metering;

plasticizing the extruder to form uniform melt, filtering the melt by a filter, conveying the melt to a T-shaped die head for co-extrusion, and performing casting cooling by a casting unit to form a thick sheet;

thirdly, the thick sheet is subjected to MDO and TDO biaxial stretching procedures in sequence to generate a thin film;

fourthly, the stretched film is treated by corona or flame to improve the surface tension and increase the surface polarity;

and fifthly, winding the treated film into a mother roll for aging treatment, and then slitting the film into products according to the requirements of customers.

5. The method for preparing the co-extruded soft-feel BOPP film according to claim 4, wherein the processing conditions of the one-time co-extrusion process comprise: the extrusion temperature of the lower surface layer and the core layer is 240 ℃, and the extrusion temperature of the upper surface layer functional layer is 210 ℃; the temperature of the cooling casting sheet unit is controlled to be 18-40 ℃, the air quantity of the air knife is 30Bar, and the angle is 80 degrees;

roller temperature control of the MDO: preheating the upper region at 90 ℃ and the lower region at 110 ℃; stretching the upper zone at 95 ℃ and the lower zone at 115 ℃; the upper shaping area is 80 ℃ and the lower area is 100 ℃; the stretching ratio is 4.0-4.5;

the temperature of each TDO zone is controlled to be 150-165 ℃, and the stretching ratio is 8.0-9.5; the strength of the corona or flame treatment surface is 31mN/m-48 mN/m.

6. The preparation method of the co-extruded soft-feel BOPP film as claimed in claims 4 to 5, wherein the melt index of the modified polyurethane elastomer TPE is 3 to 6; the extinction master batch is a blend of 30% of polypropylene and 70% of polyethylene; the expanded microporous master batch consists of 20 wt% of sodium carbonate salt, sodium polyhydroxylate salt and 80 wt% of isotactic polypropylene.

7. The method for preparing the co-extruded BOPP film with the soft feeling function according to claim 6, wherein the antistatic master batch comprises 75-85 wt% of isotactic polypropylene homopolymer and 15-25 wt% of polyether antistatic agent.

8. The method for preparing the co-extruded soft-feel BOPP film according to claim 6 or 7, wherein the anti-adhesion master batch consists of organic siloxane particles and isotactic polypropylene, wherein the mass of siloxane accounts for 20-30 wt% of the total mass of the anti-adhesion master batch, and the particle size of disiloxane is 1-2 μm.

The technical field is as follows:

the invention belongs to the technical field of high polymer materials, and particularly relates to a co-extrusion type soft-feel BOPP film and a preparation method thereof.

Background art:

BOPP is an abbreviation for "biaxialy organized Poly propylene", BOPP film, i.e. Biaxially Oriented polypropylene film. BOPP films are produced by first passing a melt of high molecular polypropylene through a long and narrow head to form a sheet or thick film, then stretching the film in two perpendicular directions (longitudinal and transverse) simultaneously or stepwise at a certain temperature and a set speed in a special stretching machine, and subjecting the film to appropriate cooling or heat treatment or special processing (e.g. corona, coating, etc.). The BOPP film is colorless, odorless, tasteless and nontoxic, and has high tensile strength, impact strength, rigidity, toughness and good transparency.

The soft-feeling functional film is a BOPP thin bright/matte film with special soft-feeling performance on the surface, is generally compounded with the outer surfaces of packing boxes such as high-grade gift packing boxes, wine boxes and the like, and has the function of high-grade soft smooth touch similar to fluff.

Because the surface of a common BOPP film is relatively stiff, the surface contact is relatively dry and sluggish, the experience is relatively common, in order to obtain the high-grade soft silky touch similar to fluff, a layer of soft functional coating is coated on a common BOPP base film through coating processing, the production and processing are carried out in a drying mode, a plurality of processing links are needed, the coating is generally an aqueous solvent, and the problems of complex working procedures, high energy consumption, solvent volatilization and the like exist in the processing process.

The invention seeks a BOPP film which has simple production process and a soft-feeling function and is produced by a one-time processing mode.

The invention content is as follows:

in order to solve the problems and overcome the defects of the prior art, the invention provides a co-extrusion type soft-feeling functional BOPP film and a preparation method thereof,

the first technical problem is solved: the existing BOPP basal membrane has poor elasticity, insufficient soft feeling effect and no fluff-like silky touch.

The second technical problem is solved: in order to obtain fluffy silky touch, a common BOPP base film is produced and processed in a mode of coating a layer of soft-touch functional coating on the base film and drying, multiple processing links are needed, the coating is generally an aqueous solvent, and the processing process has the disadvantages of complex working procedures, high energy consumption and solvent volatilization;

the specific technical scheme for solving the technical problems comprises the following steps: the co-extrusion type BOPP film with the soft-feel function comprises a core layer and is characterized in that a soft-feel functional upper surface layer is arranged above the core layer, an anti-adhesion lower surface layer is arranged below the core layer, a main body of the soft-feel functional upper surface layer is a modified polyurethane elastomer, and a concave-convex structure is arranged on the upper end face of the upper surface layer.

Further, the layer thickness of the soft-feeling functional upper surface layer is 2-3 um; the thickness of the core layer is 11-21 um; the thickness of the anti-adhesion lower surface layer is 1-1.5 um.

The preparation method of the co-extrusion type soft-feel BOPP film comprises the following specific steps:

the soft-feeling functional upper surface layer comprises the following components in percentage by weight: modified polyurethane elastomer (TPE): 40 to 50 wt%; extinction master batch: 0 to 30 wt%; expanded microporous masterbatch: 20-60 wt%;

the core layer consists of the following components in percentage by weight: homo-polypropylene: 95-100 wt%; antistatic master batch: 0-5 wt%;

the anti-adhesion lower surface layer comprises the following components in percentage by weight: homo-polypropylene: 90-99 wt%; anti-adhesion master batch: 1 to 10 wt%.

Further, the soft functional upper surface layer, the core layer and the anti-adhesion lower surface layer are prepared by a one-time co-extrusion method, and specifically include:

firstly, premixing selected raw materials according to formula design requirements in sequence, putting the premixed raw materials into a corresponding extruder feeding system, and conveying the premixed raw materials to a corresponding extruder after metering;

plasticizing the extruder to form uniform melt, filtering the melt by a filter, conveying the melt to a T-shaped die head for co-extrusion, and performing casting cooling by a casting unit to form a thick sheet;

thirdly, the thick sheet is subjected to MDO and TDO biaxial stretching procedures in sequence to generate a thin film;

fourthly, the stretched film is treated by corona or flame to improve the surface tension and increase the surface polarity;

and fifthly, winding the treated film into a mother roll for aging treatment, and then slitting the film into products according to the requirements of customers.

Further, the processing conditions of the primary co-extrusion process comprise: the extrusion temperature of the lower surface layer and the core layer is 240 ℃, and the extrusion temperature of the upper surface layer functional layer is 210 ℃; the temperature of the cooling casting sheet unit is controlled to be 18-40 ℃, the air quantity of the air knife is 30Bar, and the angle is 80 degrees;

roller temperature control of the MDO: preheating the upper region at 90 ℃ and the lower region at 110 ℃; stretching the upper zone at 95 ℃ and the lower zone at 115 ℃; the upper shaping area is 80 ℃ and the lower area is 100 ℃; the stretching ratio is 4.0-4.5;

the temperature of each TDO zone is controlled to be 150-165 ℃, and the stretching ratio is 8.0-9.5; the strength of the corona or flame treatment surface is 31mN/m-48 mN/m.

Further, the melt index of the modified polyurethane elastomer TPE is 3-6; the extinction master batch is a blend of 30% of polypropylene and 70% of polyethylene; the expanded microporous master batch consists of 20 wt% of sodium carbonate salt, sodium polyhydroxylate salt and 80 wt% of isotactic polypropylene.

Furthermore, the antistatic master batch is composed of 75-85 wt% of isotactic polypropylene homopolymer and 15-25 wt% of polyether antistatic agent.

Furthermore, the anti-sticking master batch is composed of organic siloxane particles and isotactic polypropylene, wherein the mass of siloxane accounts for 20-30 wt% of the total mass of the anti-sticking master batch, and the particle size of disiloxane is 1-2 mu m.

Has the advantages that:

the invention uses the modified thermoplastic elastomer TPE material to directly prepare the soft functional layer product with fluff touch through a one-step extrusion and stretching forming process, reduces the subsequent coating processing procedures,

the expanded master batch is creatively added, hollow cavities and surface protrusions are generated in the stretching process, microscopic hollow concavo-convex spherical forms are obtained on the surfaces, and the performance of a more excellent smooth touch soft effect of fluff is obtained;

simultaneously, adding or not adding an extinction master batch according to different requirements of customers to prepare a matte or bright product;

by using the polyether type antistatic agent formula, a more efficient antistatic effect is obtained, impurities and dust are not easily adsorbed by static electricity in the later period, and long-acting soft feeling is kept (the soft feeling on the surface is not adhered by the impurities); the organosilicone anti-adhesion master batch is used, the compatibility of the material with a polypropylene base material is good, the material is not easy to fall off in later storage and use, and the soft-feel performance is not influenced.

The specific implementation mode is as follows:

in the description of the invention, specific details are given only to enable a full understanding of the embodiments of the invention, but it should be understood by those skilled in the art that the invention is not limited to these details for the implementation. In other instances, well-known structures and functions have not been described or shown in detail to avoid obscuring the points of the embodiments of the invention. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The specific implementation mode of the invention is as follows: