阅读说明：本技术 一种高强可降解型纸塑复合袋及其制备方法 (High-strength degradable paper-plastic composite bag and preparation method thereof ) 是由 温从缯 周广鸿 赵典鸽 于 2020-04-26 设计创作，主要内容包括：本发明涉及一种高强可降解型纸塑复合袋及其制备方法,属于包装材料技术领域。在本发明技术方案中,采用了微晶纤维素改性大豆蛋白制备胶黏剂基体材料,与纸质表面形成有效的缠结作用,提高了胶黏剂材料与纸质层之间的结合强度,再将粘结剂涂覆至纸质层表面,改善纸质层结构强度不高,力学性能较差的缺陷,通过采用的纸质层、粘结层和塑料层均采用的是可降解的材料,在实际使用过程中,可被生物有效降解,安全绿色环保。(The invention relates to a high-strength degradable paper-plastic composite bag and a preparation method thereof, belonging to the technical field of packaging materials. According to the technical scheme, the microcrystalline cellulose modified soy protein is adopted to prepare the adhesive base material, the adhesive base material and the paper surface form an effective entanglement effect, the bonding strength between the adhesive material and the paper layer is improved, the adhesive is coated on the surface of the paper layer, the defects of low structural strength and poor mechanical property of the paper layer are overcome, and the paper layer, the bonding layer and the plastic layer are all made of degradable materials, so that the adhesive can be biologically and effectively degraded in the actual use process, and the adhesive is safe, green and environment-friendly.)

1. The utility model provides a compound bag is moulded to high strength degradable paper which characterized in that includes:

the paper layer is a paper material prepared by cutting a paper material;

the adhesive layer is a soy protein composite urea solution, is modified by microcrystalline cellulose, and is compounded with an adhesive material prepared from dichloroethane, sodium hydride and dimethyl sulfoxide modified aramid pulp, and is coated on any side of the paper layer;

the plastic layer is a composite plastic film layer formed by casting polylactic acid particles modified by blending poly (propylene glycol adipate) to the surface of the bonding layer and then pressing.

2. The high-strength degradable paper-plastic composite bag according to claim 1, wherein: the paper layer is preferably kraft paper.

3. The high-strength degradable paper-plastic composite bag according to claim 1, wherein: the coating thickness of the bonding layer is 1-2 mm.

4. The high-strength degradable paper-plastic composite bag according to claim 1, wherein: the thickness ratio of the plastic layer to the paper layer is 1: 1.

5. A preparation method of a high-strength degradable paper-plastic composite bag is characterized by comprising the following specific preparation steps:

s1, placing aramid pulp into dichloroethane, stirring and mixing, heating in an oil bath, filtering to collect a filter cake, adding the filter cake into absolute ethyl alcohol, continuing to perform heat preservation and oil bath heating treatment, standing and cooling to room temperature, performing centrifugal separation, collecting lower-layer precipitate, drying to obtain dry matrix pulp fiber, stirring and mixing dimethyl sulfoxide, sodium hydride and the dry matrix pulp fiber, adjusting the pH to 7.0, filtering and collecting the filter cake, washing, and drying to obtain modified fiber particles;

s2, respectively taking deionized water, soybean protein particles, urea and microcrystalline cellulose, stirring, mixing and collecting to obtain a mixed solution, performing ultrasonic dispersion, standing to obtain a matrix adhesive, adding modified fiber particles into the matrix adhesive, stirring, mixing, grinding, sieving, and collecting filtrate to obtain the modified adhesive;

s3, adding polytrimethylene adipate to polylactic acid, stirring and mixing, placing in a double-screw extruder, extruding and granulating, placing in a casting machine, and carrying out casting treatment to obtain molten slurry;

s4, taking the required paper, spraying a modified adhesive material on the paper, obtaining adhesive-coated kraft paper after spraying is finished, casting the molten slurry to the side, coated with the modified adhesive, of the adhesive-coated kraft paper, after casting is finished, performing compression molding, drying and collecting to obtain paper-plastic composite paper, and processing through a composite paper machine to obtain the high-strength degradable paper-plastic composite bag.

6. The method for preparing the high-strength degradable paper-plastic composite bag according to claim 5, wherein the oil bath heating temperature in step S1 is 120-130 ℃.

7. The method for preparing a high-strength degradable paper-plastic composite bag according to claim 5, wherein the mesh size of the screen in step S2 is mesh.

8. The method for preparing the high-strength degradable paper-plastic composite bag according to claim 5, wherein the casting parameters in the step S3 are as follows: setting the temperature of a main machine area to be 80-190 ℃, the temperature of a machine head area to be 200 ℃, the rotating speed of a main machine screw to be 100-300 r/min, the traction speed to be 5-10 m/min, the width of a die head of a casting machine to be 1000mm, and the gap to be 1.0mm, and carrying out casting treatment.

9. The method for preparing the high-strength degradable paper-plastic composite bag according to claim 5, wherein the compression molding in the step S4 is performed for 3-5S under 0.5-0.8 MPa.

Technical Field

The invention relates to a high-strength degradable paper-plastic composite bag and a preparation method thereof, belonging to the technical field of packaging materials.

Background

The paper-plastic bag is made up by using plastic and kraft paper through the processes of compounding, using pp-polypropylene as base material for PP woven cloth, using refined composite kraft paper as kraft paper, hot-laminating and adhering them together by means of molten plastics, making bag, forming, sewing and making three-in-one paper-plastic bag.

The paper-plastic bag is also called three-in-one composite paper bag, is a small bulk container, mainly uses manpower or forklift to implement unitized transportation, is convenient for loading and transporting small bulk powder-particle materials, has the characteristics of high strength, good water resistance, convenient loading and unloading and the like, and is the most popular and practical common packaging material at present. With the improvement and development of the process, the paper-plastic bag is more and more widely applied: the paper-plastic composite bag-composite plastic woven bag is prepared by taking a plastic woven bag as a base material and compounding the base material by a casting method in various fields of industrial packaging, food packaging, electronics, aerospace, science and technology, military industry and the like. They are mainly used for packaging powdery or granular solid materials and flexible articles such as fertilizers, synthetic materials, explosives, grains, salts, minerals and the like.

However, the existing paper-plastic composite material is easy to delaminate and damage in the use process due to poor bonding strength between paper and plastic, and meanwhile, in the scheme of preparing the paper-plastic composite bag by using the traditional PP resin as the base material, the environmental protection performance is poor, and the paper-plastic composite bag cannot be effectively degraded in the natural environment, so that effective modification of the paper-plastic composite material is necessary.

Disclosure of Invention

The invention aims to provide a high-strength degradable paper-plastic composite bag and a preparation method thereof, and aims to solve the problems in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

a high-strength degradable paper-plastic composite bag, comprising: the paper layer is a paper material prepared by cutting a paper material; the adhesive layer is a soy protein composite urea solution, is modified by microcrystalline cellulose, and is compounded with an adhesive material prepared from dichloroethane, sodium hydride and dimethyl sulfoxide modified aramid pulp, and is coated on any side of the paper layer; the plastic layer is a composite plastic film layer formed by casting polylactic acid particles modified by blending poly (propylene glycol adipate) to the surface of the bonding layer and then pressing. According to the technical scheme, the paper-plastic composite bag is prepared by adopting a three-layer structure, the bonding stability of the whole paper-plastic composite material is improved under the action of the three-layer structure of the paper layer, the bonding layer and the plastic layer, and the paper-plastic composite bag has excellent bonding strength and mechanical property compared with the traditional two-layer structure.

The paper layer is preferably kraft paper.

The coating thickness of the bonding layer is 1-2 mm.

The thickness ratio of the plastic layer to the paper layer is 1: 1.

The preparation method of the high-strength degradable paper-plastic composite bag comprises the following specific preparation steps:

s1, placing aramid pulp into dichloroethane, stirring and mixing, heating in an oil bath, filtering to collect a filter cake, adding the filter cake into absolute ethyl alcohol, continuing to perform heat preservation and oil bath heating treatment, standing and cooling to room temperature, performing centrifugal separation, collecting lower-layer precipitate, drying to obtain dry matrix pulp fiber, stirring and mixing dimethyl sulfoxide, sodium hydride and the dry matrix pulp fiber, adjusting the pH to 7.0, filtering and collecting the filter cake, washing, and drying to obtain modified fiber particles;

s2, respectively taking deionized water, soybean protein particles, urea and microcrystalline cellulose, stirring, mixing and collecting to obtain a mixed solution, performing ultrasonic dispersion, standing to obtain a matrix adhesive, adding modified fiber particles into the matrix adhesive, stirring, mixing, grinding, sieving, and collecting filtrate to obtain the modified adhesive; the microcrystalline cellulose modified soy protein is adopted to prepare the adhesive matrix material, and when the microcrystalline cellulose modified soy protein isolate acts on the paper-plastic composite material, the microcrystalline cellulose particles have small particle size and the special surface structure has strong affinity, can be filled and combined on the surface of a paper layer which can not be acted by isolated soy protein molecules to form effective entanglement with the surface of paper, improves the bonding strength between an adhesive material and the paper layer, secondly, modified aramid pulp is added into the adhesive matrix, and entanglement is formed by the aramid pulp and microcrystalline fiber yarns, effective entanglement combination is formed between the aramid fiber and the cast plastic layer, the bonding strength between the bonding layer and the plastic layer is improved, the aramid fiber and the microcrystalline cellulose are used as the three-dimensional entangled combined anchoring points, so that the mechanical strength of the whole paper-plastic composite bag material is improved;

s3, adding polytrimethylene adipate to polylactic acid, stirring and mixing, placing in a double-screw extruder, extruding and granulating, placing in a casting machine, and carrying out casting treatment to obtain molten slurry;

s4, taking the required paper, spraying a modified adhesive material on the paper, obtaining adhesive-coated kraft paper after spraying is finished, casting the molten slurry to the side, coated with the modified adhesive, of the adhesive-coated kraft paper, after casting is finished, performing compression molding, drying and collecting to obtain paper-plastic composite paper, and processing through a composite paper machine to obtain the high-strength degradable paper-plastic composite bag. The adhesive is coated on the surface of the paper layer, so that the adhesive is used as a coating layer to apply a coating structure film on the surface of the paper layer, the defects of low structural strength and poor mechanical property of the paper layer are overcome, and the mechanical property of the whole paper-plastic composite bag material is improved.

The oil bath heating temperature in the step S1 is 120-130 ℃.

The mesh size in step S2 is set as mesh.

The casting process parameters described in step S3 are: setting the temperature of a main machine area to be 80-190 ℃, the temperature of a machine head area to be 200 ℃, the rotating speed of a main machine screw to be 100-300 r/min, the traction speed to be 5-10 m/min, the width of a die head of a casting machine to be 1000mm, and the gap to be 1.0mm, and carrying out casting treatment.

The pressing and forming in the step S4 is carried out for 3-5S under 0.5-0.8 MPa.

Compared with the prior art, the invention has the beneficial effects that: (1) according to the technical scheme, the paper-plastic composite bag is prepared by adopting a three-layer structure, the bonding stability of the whole paper-plastic composite material is improved under the action of the three-layer structure of the paper layer, the bonding layer and the plastic layer, and the paper-plastic composite bag has excellent bonding strength and mechanical property compared with the traditional two-layer structure;

(2) in the technical scheme of the invention, firstly, microcrystalline cellulose modified soy protein is adopted to prepare an adhesive base material, when the microcrystalline cellulose modified soy protein isolate acts on a paper-plastic composite material, the microcrystalline cellulose particles have small particle diameter, and a special surface structure has strong affinity, and can be filled and combined on the surface of a paper layer on which soybean protein isolate molecules cannot act to form effective entanglement with the paper surface, so that the bonding strength between the adhesive material and the paper layer is improved, secondly, modified aramid pulp is added into the adhesive base body, entanglement is formed by the aramid pulp and microcrystalline cellulose filaments, effective entanglement combination is formed between the aramid fiber and a casting plastic layer, the bonding strength between the bonding layer and the plastic layer is improved, and the aramid fiber and the microcrystalline cellulose are used as bonding anchor points of three-dimensional entanglement, the mechanical strength of the whole paper-plastic composite bag material is improved;

(3) in the technical scheme of the invention, the binder is coated on the surface of the paper layer, so that the binder is used as a coating layer to apply a coating structure film on the surface of the paper layer, and the defects of low structural strength and poor mechanical property of the paper layer are overcome, thereby improving the mechanical property of the whole paper-plastic composite bag material.

(4) The paper layer, the bonding layer and the plastic layer adopted by the technical scheme of the invention are all made of degradable materials, and can be effectively degraded by organisms in the actual use process, thereby being safe, green and environment-friendly.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to the mass ratio of 1:10, placing aramid pulp in dichloroethane, stirring, mixing, placing in an oil bath at 120-130 ℃ for heating for 45-60 min, standing, cooling to room temperature and filtering, collecting filter cakes, adding the filter cakes into absolute ethyl alcohol according to the mass ratio of 1:12, stirring, mixing, continuing to perform heat preservation, oil bath for heating for 45-60 min, standing, cooling to room temperature, performing centrifugal separation, collecting lower-layer precipitates, drying in an oven at 85-90 ℃ for 6-8 h to obtain dry matrix pulp fibers, respectively weighing 45-50 parts by weight of dimethyl sulfoxide, 3-5 parts by weight of sodium hydride and 6-8 parts by weight of the dry matrix pulp fibers, placing in a three-neck flask, stirring, mixing, placing in an oven at 35-40 ℃ for heat preservation for reaction for 1-2 h, collecting reaction liquid, adjusting the pH to 7.0 by using 0.5mol/L of hydrochloric acid, filtering, collecting filter cakes, washing the filter cakes by using acetone for 3-5 times, and drying for 3-5 h, obtaining modified fiber particles; respectively weighing 45-50 parts by weight of deionized water, 10-15 parts by weight of soybean protein particles, 3-5 parts by weight of urea and 0.5-1.0 part by weight of microcrystalline cellulose, placing the mixture in a stirrer, stirring and mixing, collecting to obtain a mixed solution, placing the mixed solution in a stirrer for ultrasonic dispersion at 200-300W, standing at room temperature for 25-30 min to obtain a matrix adhesive, adding modified fiber particles into the matrix adhesive according to a mass ratio of 1:8, stirring, mixing, grinding through a 500-mesh screen, and collecting filtrate to obtain the modified adhesive; adding polytrimethylene adipate into polylactic acid according to the mass ratio of 1:15, stirring and mixing, collecting mixed particles, placing the mixed particles into a double-screw extruder, extruding, granulating and collecting modified polylactic acid particles, placing the polylactic acid particles into a casting machine, setting the temperature of a main machine region to be 80-190 ℃, the temperature of a machine head region to be 200 ℃, the rotating speed of a main machine screw to be 100-300 r/min, the traction speed to be 5-10 m/min, the width of a die head of the casting machine to be 1000mm, and the gap to be 1.0mm, and casting to obtain molten slurry; taking kraft paper, spraying a modified adhesive material on the kraft paper, controlling the spraying thickness of the modified adhesive material to be 1-2 mm, obtaining adhesive coated kraft paper after spraying is finished, casting molten slurry to the side, coated with the modified adhesive, of the adhesive coated kraft paper, controlling the casting thickness of the molten slurry and the thickness of paper money of the kraft paper to be 1:1, pressing the paper for 3-5 s under 0.5-0.8 MPa after casting is finished, drying and collecting paper-plastic composite paper, and processing and forming the paper-plastic composite paper through a composite paper machine to obtain the high-strength degradable paper-plastic composite bag.