阅读说明：本技术 利用废弃皮革材料和废弃nbr/pvc类橡塑保温材料制备类人造革材料的方法 (Method for preparing artificial leather-like material by using waste leather material and waste NBR/PVC rubber-plastic heat-insulating material ) 是由 李怡俊 白时兵 赖双鑫 李莉 王琪 于 2020-06-09 设计创作，主要内容包括：本发明提供一种利用废弃皮革材料和废弃NBR/PVC类橡塑保温材料制备类人造革材料的方法,该方法是将废弃铬鞣制皮革材料制品和废弃NBR/PVC类橡塑保温材料制品处理为粉体,再将粉体分别或是混合后加入磨盘型固相力化学反应器中碾磨粉碎,然后共混成型为类人造革材料制品。该方法利用固相剪切碾磨技术有效分离破坏了废弃铬鞣制皮革材料中交联在一起的胶原蛋白纤维束,以及有效降低了废弃NBR/PVC类橡塑保温材料中原有的交联密度,再将上述两种碾磨后的废弃材料进行组合制备类人造革材料,该材料具有良好的力学性能,实现了废弃皮革材料和废弃NBR/PVC类橡塑保温材料的高价值化回收再利用。(The invention provides a method for preparing artificial leather-like materials by using waste leather materials and waste NBR/PVC rubber-plastic heat-insulating materials. The method effectively separates and destroys collagen fiber bundles which are crosslinked together in the waste chrome tanning leather material by utilizing a solid phase shearing and grinding technology, effectively reduces the original crosslinking density in the waste NBR/PVC rubber and plastic heat-insulating material, and combines the two ground waste materials to prepare the artificial leather-like material which has good mechanical property, thereby realizing high-value recycling of the waste leather material and the waste NBR/PVC rubber and plastic heat-insulating material.)

1. A method for preparing artificial leather-like material by using waste leather material and waste NBR/PVC rubber-plastic heat-insulating material is characterized by mainly comprising the following steps in parts by weight:

(1-1) selecting waste chrome tanned leather material products or scraps, carrying out pretreatment including cleaning, and then treating and crushing the waste chrome tanned leather material products or scraps into waste leather powder with the average particle size of not more than 7 mm;

(1-2) selecting a waste NBR/PVC rubber-plastic heat-insulating material product with the NBR mass ratio of 50-80%, carrying out pretreatment including cleaning, and then processing and crushing the product into NBR/PVC powder with the particle size of not more than 6 mm;

(1-3) respectively adding the waste leather powder and the NBR/PVC powder into a millstone type solid-phase mechanochemical reactor to be milled and crushed respectively, and collecting the leather fiber separation superfine powder and the NBR/PVC superfine strip powder respectively after milling is finished; wherein, the technological parameters of the millstone type solid-phase mechanochemical reactor are as follows: the grinding pressure is 15-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 6-30 times, and the rotating speed of the grinding disc is 10-40 r/min;

(1-4) carrying out melt mixing on 30-70 parts of NBR/PVC superfine strip powder, 30-70 parts of leather fiber separation superfine powder, a polyvinyl chloride stabilizer and a plasticizer to prepare an artificial leather-like material product; wherein, the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts;

or is that,

(2-1) selecting waste chrome tanned leather material products or scraps, carrying out pretreatment including cleaning, and then treating and crushing the waste chrome tanned leather material products or scraps into waste leather powder with the average particle size of not more than 7 mm;

(2-2) selecting a waste NBR/PVC rubber-plastic heat-insulating material product with the NBR mass ratio of 50-80%, carrying out pretreatment including cleaning, and then processing and crushing the product into NBR/PVC powder with the particle size of not more than 6 mm;

(2-3) stirring and mixing 30-70 parts of waste leather powder and 30-70 parts of NBR/PVC powder uniformly, adding the mixture into a millstone type solid-phase mechanochemical reactor for grinding and crushing, and collecting the mixed superfine powder after grinding; wherein, the NBR/PVC superfine powder and the waste leather superfine powder account for 100 parts in total; the technological parameters of the millstone type solid-phase mechanochemical reactor are as follows: the grinding pressure is 15-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 6-30 times, and the rotating speed of the grinding disc is 10-40 r/min;

And (2-4) blending and molding the mixed superfine powder after grinding, the polyvinyl chloride stabilizer and the plasticizer to prepare the artificial leather-like material product.

2. The method of claim 1, further comprising: step (1-4) is to put 30-70 parts of NBR/PVC superfine strip powder, 30-70 parts of waste leather fiber separation superfine powder, a polyvinyl chloride stabilizer and a plasticizer into an internal mixer for mixing for 5-8 min, wherein the temperature of the internal mixer is 160-165 ℃, and the internal mixer is cooled and then put into a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-170 ℃, and the pressure maintaining time is 5-10 min; the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts;

step (2-4) is to uniformly mix the milled mixed superfine powder, the polyvinyl chloride stabilizer and the plasticizer by a blender, and then place the mixture in a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-175 ℃, and the pressure maintaining time is 5-10 min.

3. The method of claim 1, further comprising: step (1-4) placing 30-70 parts of NBR/PVC superfine strip powder, 30-70 parts of waste leather fiber separation superfine powder, a polyvinyl chloride stabilizer and a plasticizer into a double-screw extruder for blending at the temperature of 140-170 ℃, cooling and granulating, and then placing into a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-170 ℃, and the pressure maintaining time is 5-10 min; the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts;

Step (2-4) is to uniformly mix the milled mixed superfine powder, the polyvinyl chloride stabilizer and the plasticizer by a blender, and then place the mixture in a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-175 ℃, and the pressure maintaining time is 5-10 min.

4. The method of claim 1, further comprising: the polyvinyl chloride stabilizer in the steps (1-4) and (2-4) comprises any one of a calcium zinc stabilizer, a metal soap stabilizer and a lead salt stabilizer.

5. The method of claim 4, further comprising: and (3) 3-7 parts of calcium-zinc stabilizer is used as the polyvinyl chloride stabilizer in the steps (1-4) and (2-4).

6. The method of claim 1, further comprising: the plasticizer in the steps (1-4) and (2-4) comprises any one of phthalate plasticizers, polyester plasticizers and epoxy plasticizers.

7. The method of claim 6, further comprising: the plasticizer in the steps (1-4) and (2-4) is 2-4 parts of phthalate plasticizer; the phthalate plasticizer is at least one of dibutyl phthalate and dioctyl phthalate.

8. The method of claim 1, further comprising:

selecting the NBR/PVC rubber and plastic heat insulation material product in the step (1-2), wherein the NBR accounts for 58-60% by mass;

the technological parameters of the millstone type solid-phase mechanochemical reactor in the step (1-3) are as follows: the grinding pressure is 18-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 9-10 times, and the rotating speed of the grinding disc is 35-40 r/min;

the step (1-3) comprises 48-52 parts of NBR/PVC superfine strip powder and 48-52 parts of leather fiber separation superfine powder, wherein the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts.

9. The method of claim 1, further comprising:

selecting 78-80% of NBR by mass;

the technological parameters of the millstone type solid-phase mechanochemical reactor in the step (2-3) are as follows: the grinding pressure is 18-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 28-30 times, and the rotating speed of the grinding disc is 18-20 revolutions per minute;

and (2-3) mixing 48-52 parts of NBR/PVC superfine powder and 48-52 parts of waste leather superfine powder, wherein the total amount of the NBR/PVC superfine powder and the waste leather superfine powder is 100 parts.

10. An artificial leather-like material product produced by the method for producing an artificial leather-like material from the waste leather material and the waste NBR/PVC rubber-plastic heat insulating material according to claim 1.

Technical Field

The invention belongs to the technical field of recycling waste leather materials and waste NBR/PVC rubber-plastic heat-insulating materials, relates to a method for preparing artificial leather-like materials by using the waste leather materials and the waste NBR/PVC rubber-plastic heat-insulating materials, and particularly aims to treat the waste leather materials and the waste NBR/PVC rubber-plastic heat-insulating materials by using a mechanochemical reactor disclosed in Chinese patent ZL 95111258.9.

Background

The leather material is made into a material with collagen fiber as a main component by means of mechanical, physical and chemical processing methods, and is widely applied to leather clothing, automotive interior cushions, furniture sofas, popular leather shoe wear, wallet gloves and various leather ornaments. As early as 2005, China became the leather manufacturing center all over the world, and at the same time, a production chain integrating production, study and research is formed in China. However, a large amount of solid waste is generated in the production process of the leather industry, and in the leather forming process, a chrome tanning agent is often selected for crosslinking, so that the waste chrome tanning leather material is difficult to recycle in a simple manner, and a chemical manner is usually required in the recycling process, so that the additional cost is high, and the method is not suitable for industrial amplification.

The rubber-plastic heat-insulating material is widely applied to the industries of central air-conditioning, building, chemical engineering and the like and partial cold and hot medium pipelines and containers, has the main function of reducing cold loss and heat loss, and does not contain fiber dust, so that the material does not grow mildew. In addition, the environment-friendly effect is good during construction, and the method can be widely used. The NBR/PVC blended rubber is a commercial material variety widely applied to rubber and plastic heat-insulating materials, has good mechanical properties and high flame retardance and chemical resistance, and has been applied for over seventy years. The NBR/PVC rubber-plastic heat-insulating material generally introduces a cross-linking structure into the material to ensure the heat resistance and the structural stability of the rubber-plastic heat-insulating material so as to prolong the service life of the rubber-plastic heat-insulating material.

But meanwhile, the NBR/PVC rubber-plastic heat-insulating material has the characteristics of insolubility and infusibility due to higher crosslinking degree and complex crosslinking mechanism. Generally, the traditional polymer processing method cannot destroy the strong covalent bond effect between the cross-linking points of the NBR/PVC rubber-plastic heat-insulating material, and is difficult to recover from the polymer network structure to the plastic linear macromolecular structure. Furthermore, due to the entropy elasticity characteristic of the macromolecular chains of the polymer, when the polymer is subjected to solution and melting treatment, the macromolecular chains stretch, the distance between cross-linking points is increased, the conformational entropy is reduced, the process belongs to the process of entropy reduction, and the thermodynamic law is not met, so that the macromolecular chains retract, the orientation rearrangement of macromolecules is limited, and the cross-linked macromolecular material cannot be processed and molded. Therefore, it is naturally impossible to treat the waste NBR/PVC-based rubber and plastic heat insulating materials, such as waste rubber materials and thermosetting resins, by solution and melt processing methods (D.Wim, W.Johan et al, Chemical Science,2016, 7). The waste rubber-plastic heat-insulating material is difficult to realize high-valued recycling through conventional recovery methods such as solution, melting, landfill, incineration and the like, and only can realize conventional waste treatment.

At present, in the treatment mode of the waste NBR/PVC rubber-plastic heat-insulating materials, landfill and incineration are the main recovery treatment means. However, the conventional landfill and incineration treatment has the following problems in the treatment mode aiming at the waste NBR/PVC rubber and plastic heat-insulating materials: only a simple landfill mode is adopted, large-area land resource waste can be caused, and even methane leakage and other chemical substance leakage can occur to cause soil pollution; by adopting incineration treatment, harmful gases such as furan, dioxin, dust, hydrogen chloride and the like can be generated, equipment is easy to corrode, carcinogenesis is caused to human bodies, serious secondary environmental pollution is caused, and waste removal equipment with higher matching cost is usually required.

Therefore, the above recycling technology can not solve the problems of high value, low cost and zero waste recycling of the waste NBR/PVC rubber-plastic thermal insulation materials and chrome tanned leather waste materials, and therefore, there is a need to develop a new process and a new technology for recycling the chrome tanned leather waste materials and the waste NBR/PVC rubber-plastic thermal insulation materials, and if the waste materials can be combined to realize zero waste recycling, the recycling technology has an excellent commercial value.

Disclosure of Invention

The invention aims to solve the problems in the background art and provides a method for preparing an artificial leather-like material by utilizing a waste leather material and a waste NBR/PVC rubber-plastic heat-insulating material, the method effectively separates and destroys collagen fiber bundles which are originally crosslinked together through hydrogen bonds between hydroxyl groups and chromium ion metal coordination coupling action in the waste chrome tanning leather material by utilizing a solid-phase shearing and grinding technology, increases an active reaction interval and forms a good composite interface, effectively reduces the original crosslinking density in the waste NBR/PVC rubber-plastic heat-insulating material, and then combines the two ground waste materials to prepare the artificial leather-like material, wherein the material has good mechanical property, and realizes high-value recycling of the waste leather material and the waste NBR/PVC rubber-plastic heat-insulating material.

In order to achieve the purpose, the invention adopts the technical scheme formed by the following technical measures.

A method for preparing artificial leather-like material by using waste leather material and waste NBR/PVC rubber-plastic heat-insulating material mainly comprises the following steps in parts by weight:

(1-1) selecting waste chrome tanned leather material products or scraps, carrying out pretreatment including cleaning, and then treating and crushing the waste chrome tanned leather material products or scraps into waste leather powder with the average particle size of not more than 7 mm;

(1-2) selecting a waste NBR/PVC rubber-plastic heat-insulating material product with the NBR mass ratio of 50-80%, carrying out pretreatment including cleaning, and then processing and crushing the product into NBR/PVC powder with the particle size of not more than 6 mm;

(1-3) respectively adding the waste leather powder and the NBR/PVC powder into a millstone type solid-phase mechanochemical reactor to be milled and crushed respectively, and collecting the leather fiber separation superfine powder and the NBR/PVC superfine strip powder respectively after milling is finished; wherein, the technological parameters of the millstone type solid-phase mechanochemical reactor are as follows: the grinding pressure is 15-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 6-30 times, and the rotating speed of the grinding disc is 10-40 r/min;

(1-4) carrying out melt mixing on 30-70 parts of NBR/PVC superfine strip powder, 30-70 parts of leather fiber separation superfine powder, a polyvinyl chloride stabilizer and a plasticizer to prepare an artificial leather-like material product; wherein, the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts;

or is that,

(2-1) selecting waste chrome tanned leather material products or scraps, carrying out pretreatment including cleaning, and then treating and crushing the waste chrome tanned leather material products or scraps into waste leather powder with the average particle size of not more than 7 mm;

(2-2) selecting a waste NBR/PVC rubber-plastic heat-insulating material product with the NBR mass ratio of 50-80%, carrying out pretreatment including cleaning, and then processing and crushing the product into NBR/PVC powder with the particle size of not more than 6 mm;

(2-3) stirring and mixing 30-70 parts of waste leather powder and 30-70 parts of NBR/PVC powder uniformly, adding the mixture into a millstone type solid-phase mechanochemical reactor for grinding and crushing, and collecting the mixed superfine powder after grinding; wherein, the NBR/PVC superfine powder and the waste leather superfine powder account for 100 parts in total; the technological parameters of the millstone type solid-phase mechanochemical reactor are as follows: the grinding pressure is 15-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 6-30 times, and the rotating speed of the grinding disc is 10-40 r/min;

And (2-4) blending and molding the mixed superfine powder after grinding, the polyvinyl chloride stabilizer and the plasticizer to prepare the artificial leather-like material product.

Wherein, the waste chrome tanned leather material products or scraps obtained by chrome tanning in the leather industry are the waste chrome tanned leather material products or scraps obtained by the steps (1-1) and (2-1).

Wherein, the steps (1-1) and (2-1) include the pretreatment of cleaning, which is mainly to remove the impurities on the surface of the waste leather products or scraps, and if necessary, to remove the non-leather materials, and the technicians in the field can perform specific treatment according to the prior art according to the actual condition of the waste leather products or scraps which need to be recycled.

Wherein, the waste NBR/PVC rubber and plastic heat insulation material products in the steps (1-2) and (2-2) are plastic heat insulation material products mainly comprising NBR/PVC materials, the common products are heat insulation pipes and heat insulation plates, and a person skilled in the art can inquire the specification of the rubber and plastic heat insulation material products to determine whether the specifications of the rubber and plastic heat insulation material products meet the requirements of using the products as raw materials of the recycling process.

Wherein, the steps (1-2) and (2-2) comprise the cleaning pretreatment, which is mainly to remove impurities on the surface of the waste products, if necessary, the non-NBR/PVC material is partially removed, and the technical personnel can carry out the specific treatment according to the prior art according to the actual condition of the waste NBR/PVC rubber-plastic heat-insulating material products needing to be recycled.

Conventionally, the NBR/PVC powder having a particle size of not more than 6mm obtained by the treatment in steps (1-2) and (2-2) is treated by conventional facilities of the prior art of pulverization such as a planetary ball mill, a jaw crusher, a freeze ball mill, etc.

Wherein, the millstone type solid-phase mechanochemical reactor in the steps (1-3) and (2-3) is the mechanochemical reactor disclosed in the patent ZL 95111258.9 previously issued by the applicant of the invention, and the temperature of the millstone is controlled by introducing constant-temperature circulating liquid medium into the millstone. Typically, the liquid medium is water or ethylene glycol.

Wherein, the products prepared by the steps (1-4) and (2-4) are artificial leather-like products, and the technical personnel in the field can select proper process conditions according to the target products needed by the artificial leather-like materials by referring to the prior art, in order to better illustrate the invention and provide several technical schemes for reference, the steps (1-4) and (2-4) can be specifically as follows:

firstly, putting 30-70 parts of NBR/PVC superfine strip powder, 30-70 parts of waste leather fiber separation superfine powder, a polyvinyl chloride stabilizer and a plasticizer into an internal mixer for mixing for 5-8 min, wherein the temperature of the internal mixer is 160-165 ℃, and cooling and then putting the internal mixer into a flat vulcanizing machine for processing to obtain an artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-170 ℃, and the pressure maintaining time is 5-10 min; the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts;

Step (2-4) is to uniformly mix the milled mixed superfine powder, the polyvinyl chloride stabilizer and the plasticizer by a blender, and then place the mixture in a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-175 ℃, and the pressure maintaining time is 5-10 min.

Secondly, putting 30-70 parts of NBR/PVC superfine strip powder, 30-70 parts of waste leather fiber separation superfine powder, a polyvinyl chloride stabilizer and a plasticizer into a double-screw extruder for blending at the temperature of 140-170 ℃, cooling and granulating, and then putting into a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-170 ℃, and the pressure maintaining time is 5-10 min; the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts;

step (2-4) is to uniformly mix the milled mixed superfine powder, the polyvinyl chloride stabilizer and the plasticizer by a blender, and then place the mixture in a flat vulcanizing machine for processing to obtain the artificial leather-like composite board; the technological parameters of the flat vulcanizing machine are as follows: the pressure is 10-12 Mpa, the temperature is 165-175 ℃, and the pressure maintaining time is 5-10 min.

Wherein, the polyvinyl chloride stabilizer in the steps (1-4) and (2-4) is a processing heat stabilizer for polyvinyl chloride, which is conventionally used in the field of polyvinyl chloride processing, and comprises a calcium-zinc stabilizer, a metal soap stabilizer and a lead salt stabilizer, and it is worth to be noted that the addition amount of the polyvinyl chloride stabilizer is consistent with the polyvinyl chloride processing technology in the prior art, and a technician can judge the specific addition amount according to the selected polyvinyl chloride stabilizer; in order to better illustrate the invention and provide a technical scheme for reference, the polyvinyl chloride stabilizer in the steps (1-4) and (2-4) is 3-7 parts of calcium zinc stabilizer.

Wherein, the plasticizer in the steps (1-4) and (2-4) is a plasticizer for polyvinyl chloride which is conventionally used in the field of polyvinyl chloride processing, and comprises a phthalate plasticizer, a polyester plasticizer and an epoxy plasticizer, and it is worth to be noted that the addition amount of the plasticizer is consistent with that of the polyvinyl chloride processing technology in the prior art, and a technician can judge the specific addition amount according to the selected plasticizer; in order to better illustrate the invention and provide a technical scheme for reference, the plasticizer in the steps (1-4) and (2-4) is 2-4 parts of phthalate plasticizer. Further preferably, the phthalate plasticizer is at least one of dibutyl phthalate and dioctyl phthalate.

It is worth to be noted that, in the technical scheme of the invention, in order to improve the mechanical property of the finally prepared artificial leather-like material product, the invention principle is that the milled chrome tanning leather material is separated from collagen fibers, and more active sites exposed on the fiber surface are easy to react. Meanwhile, the grinding process destroys the hydrogen bond function and the chromium ion coordination function on the surface of the collagen fiber, and hydroxyl and chromium ions are exposed on the surface layer of the leather fiber, so that the NBR/PVC rubber-plastic material subjected to crosslinking release is easier to interact. The hydroxyl presents polarity, according to the principle of similar intermiscibility, the leather fiber is easy to blend polar rubber and plastic materials, and meanwhile, the coordination effect of chromium ions is easy to occur in the cyano part of the NBR component, so that the interface interaction between the leather fiber and the rubber and plastic materials is enhanced, and the improvement of the mechanical property of the artificial leather-like material is facilitated.

After the chrome tanning leather material is treated by the solid phase shearing and grinding technology, taking the chrome tanning pigskin material as an example, along with the increase of the grinding times of the solid phase mechanochemical reactor, the structure of the collagen fiber bundles of the waste chrome tanning leather material is damaged, the diameter of the collagen fiber bundles is reduced, and the collagen fiber bundles bound together after grinding are gradually separated (attached figures 1 and 2 in the specification). The appearance of a single fiber bundle structure can be obviously observed in an electron microscope picture, which shows that the decrosslinking degree of the waste chrome tanned leather material powder is gradually increased in the milling process, the characteristic area of the fiber bundle is increased, the active reaction interval is increased, and a good composite interface is easier to form between the waste chrome tanned leather material powder and the waste rubber and plastic powder which is subjected to the same disc-shaped mechanochemical reactor.

Meanwhile, through comparison experiments of the inventor of the invention, the inventor discovers that if the NBR/PVC material is only subjected to crushing treatment, even if the particle size of the NBR/PVC material is 3000-6000 mu m, the crosslinking density of the NBR/PVC material still reaches 68.04% through tests, when the NBR/PVC material is used as a main component of an artificial leather-like material product, the toughness and the impact performance of the obtained sample material are improved to a limited extent, because the blended rubber-plastic material has overlarge particle size and high crosslinking degree, a good interface effect is difficult to form with a leather material, and a stress concentration point is easy to form, the mechanical property of the sample material cannot be compared with the property of a commercial leather.

After the treatment of the solid-phase shearing and grinding technology, along with the increase of the number of times of circular grinding in the technological parameters, the original cellular structure (attached figure 3 in the specification) in the NBR/PVC material ultrafine powder is completely collapsed, the particle size is reduced, and the micro-morphology of the powder is gradually changed into a strip shape when the powder is circularly ground for 4 times. The occurrence of the strip-shaped structure shows that the decrosslinking degree of the NBR/PVC material is gradually increased in the milling process, so that the mobility of the polymer chain is increased, and the powder particles are more easily heated, softened and fused in the collision process (figure 4 in the specification).

The research of the inventor of the invention finds that under the action of strong shearing force of solid-phase grinding, the original crosslinking bond in the NBR/PVC material ultrafine powder is broken, the crosslinking density is reduced to be less than 53.15 percent through testing, the uncrosslinked crosslinking regeneration of insoluble and infusible crosslinking waste materials is realized, and conditions are created for realizing thermoplastic processability of the material.

The particle size distribution diagrams of the leather fiber separation superfine powder and the NBR/PVC material superfine strip powder after grinding are shown in the attached figures 5 and 6 in the specification. From fig. 6, it is apparent that the diameter of collagen fiber bundles in the leather after grinding is gradually reduced along with the increase of the solid phase shearing pass, which is beneficial to destroying the interaction force among the fiber bundles and endowing the leather with the potential of recycling; tests prove that the NBR/PVC rubber plastic material powder has increased granularity (because of tending to strip) along with the increase of the number of times of the circulating grinding, and the difference between the powder granularities is reduced, thereby being beneficial to preparing high-uniformity powder products. It is evident from FIG. 8 that the particle size of the milled NBR/PVC material powder tends to be uniform, and the SEM results show that the ultrafine NBR/PVC material powder tends to be in the form of stripes gradually along with the milling process.

In addition, the PVC component in the NBR/PVC rubber-plastic heat-insulating material does not generate a cross-linking structure in the production process, the proportion is large, and the PVC component is easy to be converted into an artificial leather-like base material during melt blending. The NBR rubber particles induce silver lines and shear bands to improve the mechanical property of the artificial leather-like product when being subjected to external force. The leather fiber has shortened fiber length and disappeared fiber bundles due to the shearing action in the grinding process, and can play a role similar to a chopped fiber reinforced artificial leather PVC matrix.

By combining the conditions, the toughness and the impact property of the artificial leather-like material product prepared by the technical scheme of the invention are greatly improved, and the artificial leather-like material product has excellent commercial value.

It is noted that, as a result of the research of the present inventors, it was found that the mechanical properties of the artificial leather-like material product prepared by the waste leather powder and the NBR/PVC powder are better than those obtained by adding the waste leather powder and the NBR/PVC powder to a millstone-type solid-phase mechanochemical reactor and grinding them respectively (i.e., steps (1-1) to (1-4)), and then adding the waste leather powder and the NBR/PVC powder to the millstone-type solid-phase mechanochemical reactor and grinding them uniformly (i.e., steps (2-1) to (2-4)). Presumably, during solid phase shearing and co-milling, the uncrosslinked NBR/PVC rubber-plastic heat-insulating material and the fully peeled leather fibers are contacted more fully, mixed more uniformly and have better interface interaction, for example, metal chromium ions are formed to form metal coordination with cyano groups in the rubber-plastic material and hydroxyl groups in the leather material, and the hydroxyl groups among the leather fibers and chlorine in the rubber-plastic material form hydrogen bonds and other interactions, so that the prepared leather rubber-plastic composite material has better mechanical properties.

Among them, in order to obtain the artificial leather-like material product with better comprehensive performance, preferably:

the waste NBR/PVC rubber and plastic heat-insulating material products in the steps (1-2) and (2-2) are respectively 58-60% and 78-80% of NBR by mass.

The technological parameters of the millstone type solid-phase mechanochemical reactor in the step (2-3) are as follows: the grinding pressure is 18-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 28-30 times, and the rotating speed of the grinding disc is 18-20 revolutions per minute;

the technological parameters of the millstone type solid-phase mechanochemical reactor in the step (1-3) are as follows: the grinding pressure is 18-20 KN, the surface temperature of the grinding disc is controlled by introducing a constant-temperature circulating liquid medium with the temperature of-10 to-12 ℃, the grinding disc is circularly ground for 9-10 times, and the rotating speed of the grinding disc is 35-40 r/min;

step (2-3) is to use 48-52 parts of NBR/PVC superfine powder and 48-52 parts of waste leather superfine powder, wherein the total amount of the NBR/PVC superfine powder and the waste leather superfine powder is 100 parts;

the step (1-3) comprises 48-52 parts of NBR/PVC superfine strip powder and 48-52 parts of leather fiber separation superfine powder, wherein the total amount of the NBR/PVC superfine strip powder and the leather fiber separation superfine powder is 100 parts.

Generally, the above-mentioned cyclic milling process is implemented by milling the mixture in a millstone-type solid-phase mechanochemical reactor, collecting the product at the discharge end, and then placing the product in the millstone-type solid-phase mechanochemical reactor again for milling, and the above-mentioned process is regarded as cyclic milling for 1 time.

In general, in addition to the stabilizer and plasticizer, other processing aids such as antioxidants, flame retardants, antioxidants, and the like known in the art may be added. However, it is a prerequisite that these processing aids do not adversely affect the achievement of the objects of the present invention and the achievement of the advantageous effects of the present invention.

According to one technical scheme of the invention, the obtained artificial leather-like material product has the tensile strength of 8-16 MPa and the elongation at break of 30-50%, and is shown in the attached figure 5 in the specification.

The invention has the following beneficial effects:

1. the method effectively separates and destroys collagen fiber bundles which are originally crosslinked together through hydrogen bonds between hydroxyl groups and coordination and coupling effects of chromium ions and metals in the waste chrome tanning leather material by utilizing a solid phase shearing and grinding technology, increases an active reaction interval, forms a good composite interface, effectively reduces the original crosslinking density in the waste NBR/PVC rubber and plastic heat-insulating material, combines the two ground waste materials to prepare the artificial leather-like material, has good mechanical property, and realizes high-value recycling and reutilization of the waste leather material and the waste NBR/PVC rubber and plastic heat-insulating material

2. The invention effectively reduces the original crosslinking density in the waste NBR/PVC rubber and plastic heat-insulating material by utilizing the solid-phase shearing and grinding technology, further researches the de-crosslinking condition of the high-crosslinking density material under the action of strong shearing force of the solid-phase grinding, and provides guidance for further improving the problem of recycling the waste NBR/PVC rubber and plastic heat-insulating material in future.

3. The invention is based on the solid phase shearing technology, has simple production process, easy operation, batch and continuous production, is suitable for most of waste chrome tanning leather materials and waste NBR/PVC rubber and plastic heat insulation materials, and has obvious commercial popularization advantage.

Drawings

FIG. 1 is an SEM photograph of the ultrafine powder of waste leather in example 6 of the present invention.

FIG. 2 is an SEM photograph of the milled leather defibration micropowder of example 6 of the present invention.

FIG. 3 is an SEM photograph of the NBR/PVC ultrafine powder in example 6 of the present invention.

FIG. 4 is an SEM photograph of the milled NBR/PVC ultrafine powder of example 6.

FIG. 5 is a particle size distribution diagram of the waste leather micropowder of example 6 according to the present invention.

FIG. 6 is a graph showing the distribution of the particle size of the leather defibration ultra fine powder after grinding in example 6 of the present invention.

FIG. 7 is a distribution diagram of the particle size of the NBR/PVC ultrafine powder in example 6 of the present invention.

FIG. 8 is a graph showing the particle size distribution of milled NBR/PVC ultra-fine powder in example 1.

FIG. 9 is a photograph (left drawing) of a waste chrome tanned leather material product of example 6 of the present invention after pretreatment, and a photograph (right drawing) of a leather fiber-separated ultrafine powder collected after grinding and pulverizing in a solid-phase mechanochemical reactor.

FIG. 10 is a photograph of the NBR/PVC rubber-plastic heat insulating material product of example 6 of the present invention after pretreatment (left drawing) and a photograph of the NBR/PVC ultra-fine strip powder collected after grinding and pulverization in the solid-phase mechanochemical reactor (right drawing).

Detailed Description

The invention is further illustrated by the following examples in conjunction with the accompanying drawings. It should be noted that the examples given are not to be construed as limiting the scope of the invention, and that those skilled in the art, on the basis of the teachings of the present invention, will be able to make numerous insubstantial modifications and adaptations of the invention without departing from its scope.

It is noted that Scanning Electron Microscope (SEM) is used in the examples to examine the appearance of the powder of the rubber-plastic thermal insulation material with different grinding passes.

The blue light particle size analyzer is used for inspecting the particle size, namely the particle size distribution, of the rubber-plastic heat-insulating material powder with different grinding passes.

The mechanical properties were measured according to ASTM D412 with a running speed of 5mm/min for the chucks.