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CN-121989540-A - Rebound type composite sheet and preparation method thereof

CN121989540ACN 121989540 ACN121989540 ACN 121989540ACN-121989540-A

Abstract

The invention discloses a rebound type composite sheet and a preparation method thereof, and belongs to the technical field of composite sheets. The sheet comprises an inner layer, a rebound layer, a barrier layer and an outer layer which are sequentially laminated, wherein the base material of the rebound layer is polyester or polyamide, the tensile strength of the rebound layer is more than or equal to 150MPa, the elongation at break is more than or equal to 50%, the thickness of the rebound layer is 10-30 mu m, the melt flow rate of the polyester under the conditions of 275 ℃ per 2.16kg is controlled to be 5-20 g/10min, and/or the melt flow rate of the polyamide under the conditions of 235 ℃ per 2.16kg is controlled to be 5-18 g/10min. The rebound layer also comprises functional aids such as maleic anhydride grafted polyethylene, oxazoline grafted polyolefin and the like, and the polyester or the polyamide is preferably subjected to biaxial stretching treatment. The preparation method comprises corona treatment of each layer of substrate film, sequentially compounding each layer at different temperatures and pressures by adopting a step-by-step dry compounding process, and finally curing. The invention is used for improving the rebound resilience performance of the composite sheet packaging.

Inventors

  • GAO WEI

Assignees

  • 江阴宝柏新型包装材料有限公司
  • 安姆科科技研发有限公司

Dates

Publication Date
20260508
Application Date
20260108

Claims (10)

  1. 1. A rebound type composite sheet is characterized by comprising an inner layer, a rebound layer, a barrier layer and an outer layer which are sequentially laminated, wherein a base material of the rebound layer is at least one of polyester or polyamide, the tensile strength of the base material is more than or equal to 150MPa, the elongation at break is more than or equal to 50%, the thickness of the base material is 10-30 mu m, the melt flow rate of the polyester at 275 ℃ per 2.16kg is 5-20 g/10min, and/or the melt flow rate of the polyamide at 235 ℃ per 2.16kg is 5-18 g/10min.
  2. 2. The rebound composite sheet according to claim 1, wherein the rebound layer comprises, by mass, 72% -88% of polyester and/or polyamide, 6% -15% of maleic anhydride grafted polyethylene, 3% -8% of oxazoline grafted polyolefin, 0.2% -2% of a flow accelerator and 0.2% -2% of a foaming agent.
  3. 3. The rebound type composite sheet according to claim 2, wherein the preparation method of the oxazoline grafted polyolefin comprises the steps of carrying out free radical grafting reaction on polyolefin resin and oxazoline monomer in the presence of an organic peroxide initiator in a melt extrusion process, wherein the addition amount of the initiator is 0.1% -1% of the mass of the polyolefin resin, and the reaction temperature is 180-220 ℃.
  4. 4. A rebound type composite sheet according to claim 3, wherein the oxazoline monomer is at least one selected from the group consisting of 2-vinyl-2-oxazoline and 2-isopropenyl-2-oxazoline.
  5. 5. The rebound type composite sheet material as claimed in claim 1 or 2, wherein in the rebound layer, The polyester is at least one of polyethylene terephthalate, polybutylene terephthalate and polybutylene naphthalate treated by a biaxial stretching process; The polyamide is at least one selected from polycaprolactam, polyhexamethylene adipamide and polydodecyl amide treated by biaxial stretching process.
  6. 6. The resilient composite sheet of claim 5, wherein the sheet is, The biaxial stretching treatment of the polyester comprises stretching the polyester at a temperature above the glass transition temperature and below the melting point of the polyester by 3-4 times in the longitudinal direction, stretching the polyester by 3-4 times in the transverse direction, and performing heat setting treatment; The biaxial stretching treatment of the polyamide comprises stretching the polyamide at a temperature above the glass transition temperature and below the melting point of the polyamide by 2.5-3.5 times in the longitudinal direction, stretching the polyamide at a temperature 2.5-3.5 times in the transverse direction, and performing heat setting treatment.
  7. 7. The rebound type composite sheet according to claim 1, wherein the substrate of the inner layer and/or the outer layer is at least one selected from the group consisting of low density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyolefin elastomer, and/or The thickness of the inner layer is 50-80 mu m, and the thickness of the outer layer is 80-140 mu m.
  8. 8. The rebound type composite sheet according to claim 1, wherein the base material of the barrier layer is at least one selected from ethylene-vinyl alcohol copolymer, polyvinylidene chloride, aluminized polyester film, silicon oxide plated polyester film, and/or The thickness of the barrier layer is 10-25 mu m.
  9. 9. The rebound type composite sheet according to claim 1, wherein the inner layer and/or the outer layer is/are embossed film, and the surface of the embossed film is provided with an embossed pattern having a depth of 5 to 20 μm and a linear density of 80 to 200 lines/inch.
  10. 10. A method of producing a rebound type composite sheet according to any one of claims 1 to 9, comprising the steps of: s01, respectively carrying out corona treatment on the inner layer, the rebound layer, the barrier layer and the outer layer base material film, so that the surface tension is more than or equal to 38mN/m; s02, coating an adhesive on one side of the rebound layer, and performing dry compositing with an inner layer substrate film, wherein the compositing temperature is 60-75 ℃ and the compositing pressure is 0.3-0.5 MPa; S03, coating an adhesive on the other side of the rebound layer, and carrying out dry-process compounding with a base material film of the barrier layer, wherein the compounding temperature is 70-80 ℃, and the compounding pressure is 0.35-0.45 MPa; s04, coating an adhesive on the other side of the barrier layer, and performing dry-process compounding with the outer layer substrate film, wherein the compounding temperature is 65-80 ℃ and the compounding pressure is 0.4-0.5 MPa; s05, curing the compounded sheet for 24-48 hours at the temperature of 40-50 ℃ to obtain the rebound type composite sheet.

Description

Rebound type composite sheet and preparation method thereof Technical Field The invention relates to the technical field of composite sheets, in particular to a rebound type composite sheet and a preparation method thereof. Background In the field of daily chemical product packaging, packaging of contents such as toothpaste, cosmetics and the like in the form of a hose has become a mainstream industry, and the packaging core of the packaging has been required to include good flexibility, barrier property, formability and key rebound resilience. After the ideal hose is used for extruding the content, the pressed part can rebound to the initial shape rapidly and completely, so that the outside air and the moisture can be effectively reduced and enter the hose, the content is prevented from oxidative deterioration, the attractive appearance of the hose body can be maintained, and the use experience of a user is improved. Currently, most of the commercially available hose sheets are based on a single polyethylene and are compounded with a barrier material. Although the structure can meet the basic packaging and blocking requirements, the rebound resilience performance is generally poor, namely, the extruded hose part is extremely easy to collapse and deform and can not be quickly restored to the original state, and even permanent deformation can be generated after long-term use, so that the reliability and appearance of the packaging are affected. In order to solve the rebound problem, the prior art generally adopts two paths, namely, simply increasing the overall thickness of the sheet, but directly leading to the decrease of the flexibility of the hose and the hardness of hand feeling when extruding the content, and trying to blend rubber elastomer into PE for modification, but because of poor compatibility of the two, the problems of interlayer separation, material embrittlement and the like are easily caused, and meanwhile, the production cost is increased. Therefore, development of a novel composite material structure capable of improving the rebound performance of a hose without sacrificing flexibility and economy has become an urgent technical requirement of the industry. Disclosure of Invention The invention aims to overcome the defects of the prior art and solve at least one of the problems in the background art. In order to achieve the above purpose, the technical scheme provided by the invention is as follows. The rebound type composite sheet comprises an inner layer, a rebound layer, a barrier layer and an outer layer which are sequentially laminated, wherein the base material of the rebound layer is at least one of polyester or polyamide, the tensile strength of the base material is more than or equal to 150MPa, the elongation at break is more than or equal to 50%, the thickness of the base material is 10-30 mu m, the melt flow rate of the polyester at 275 ℃ per 2.16kg is 5-20 g/10min, and/or the melt flow rate of the polyamide at 235 ℃ per 2.16kg is 5-18 g/10min. As a preferable technical scheme, the rebound layer comprises, by mass, 72% -88% of polyester and/or polyamide, 6% -15% of maleic anhydride grafted polyethylene, 3% -8% of oxazoline grafted polyolefin, 0.2% -2% of flow promoter and 0.2% -2% of foaming agent. According to the preparation method of the oxazoline grafted polyolefin, a free radical grafting reaction is carried out on polyolefin resin and an oxazoline monomer in the presence of an organic peroxide initiator in a melt extrusion process, the addition amount of the initiator is 0.1% -1% of the mass of the polyolefin resin, and the reaction temperature is 180-220 ℃. As a preferable technical scheme, the oxazoline monomer in the oxazoline grafted polyolefin is at least one selected from 2-vinyl-2-oxazoline and 2-isopropenyl-2-oxazoline. In the preferred technical scheme, the polyester in the rebound layer is at least one selected from polyethylene terephthalate, polybutylene terephthalate and polybutylene naphthalate treated by a biaxial stretching process, and the polyamide is at least one selected from polycaprolactam, polyhexamethylene adipamide and polydodecyl amide treated by the biaxial stretching process. The technical scheme is that the biaxially stretching treatment of the polyester in the rebound layer comprises stretching the polyester above the glass transition temperature and below the melting point by 3-4 times in the longitudinal direction, stretching the polyester by 3-4 times in the transverse direction and then performing heat setting treatment, and the biaxially stretching treatment of the polyamide comprises stretching the polyamide above the glass transition temperature and below the melting point by 2.5-3.5 times in the longitudinal direction, stretching the polyester by 2.5-3.5 times in the transverse direction and performing heat setting treatment. As a preferable technical scheme, the base material of the inner layer and/or the outer layer is at least one s