Preparation method of polyurethane adhesive / waste residue plastic composite material

Abstract

The present invention provides a method for preparing a polyurethane adhesive / waste plastic composite material, which comprises the following steps: preparing dry modified waste plastic and polyester polyol respectively; after mixing the polyester polyol and the dry modified waste plastic, adding (3-aminopropyl) triethoxysilane, mixing, then adding toluene-2,4-diisocyanate and dibutyltin dilaurate, stirring evenly, obtaining a polyurethane adhesive / waste plastic slurry, shaping, and heat curing in a vacuum to obtain the polyurethane adhesive / waste plastic composite material. The composite material of the present invention not only maintains the mechanical properties of polyurethane, but also reduces the cost of polyurethane adhesive / filler composite material, improves PET waste and waste plastic to the greatest extent, enters the negative effects caused by the environment, solves the problem of high production cost of traditional composite materials, and can effectively avoid the harm to the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of environmentally friendly material preparation, and particularly relates to a polyurethane adhesive / waste residue plastic composite material and a preparation method thereof. Background Art

[0002] my country is a major consumer of plastics. Every year, a large amount of plastic waste is generated due to the use of materials such as "plastics replacing steel" and "plastics replacing wood". The waste plastics buried underground and in the ocean will increase the environmental burden and seriously weaken the environmental carrying capacity, leading to many environmental problems. As my country continues to increase its control over solid waste pollution emissions, using waste plastics as fillers for polyurethane adhesive composite materials can not only reduce the negative impact of waste plastics on the environment, but also increase the utilization rate of plastic waste, contributing to the promotion of my country's ecological civilization construction and sustainable development.

[0003] Waste PET plastic is the main solid waste in the production process of life. Polyester represented by polyethylene terephthalate (PET) has excellent mechanical, optical and gas barrier properties. In recent years, with the depletion of non-renewable resources such as petroleum, the recycling of waste polyester has attracted increasing attention and has shown good application prospects in the preparation of polyurethane adhesives.

[0004] Traditional production of polyurethane sheets generally requires the reaction of a large amount of industrial raw materials polyester polyol and TDI, which not only has a negative impact on the environment, but also causes a large amount of resource waste. Summary of the invention

[0005] The purpose of the present invention is to provide a polyurethane adhesive / waste residue plastic composite material and a preparation method thereof. The composite material is prepared using cheap and readily available industrial waste PET polyester plastic and waste residue plastic as raw materials, has good social and economic benefits for the shortage of raw materials in building material production, and is suitable for large-scale production of building material composite materials.

[0006] A method for preparing a polyurethane adhesive / waste residue plastic composite material comprises the following steps:

[0007] preparing dry-process modified waste residue plastics and polyester polyols respectively;

[0008] After the polyester polyol and the dry modified waste residue plastic are mixed, a silane diluent is added and mixed, and then isocyanate and dibutyltin dilaurate are added and stirred evenly to obtain a polyurethane adhesive / waste residue plastic slurry, which is shaped and thermally cured in a vacuum to obtain the polyurethane adhesive / waste residue plastic composite material.

[0009] As a preferred embodiment, the preparation method of the dry modified waste residue plastic is:

[0010] After the waste plastic is washed, dried and crushed, the wood chips are evenly mixed and crushed again to obtain dry-process modified waste plastic.

[0011] As a preferred solution, the amount of wood chips added is 2-8.5% of the weight of the waste plastic.

[0012] As a preferred embodiment, the preparation method of the polyester polyol is:

[0013] The pretreated PET waste and diethylene glycol are mixed in a weight ratio of 1:2, zinc oxide is added, and the mixture is reacted at 190-220° C. to obtain polyester polyol.

[0014] As a preferred solution, the pretreatment method of the PET waste is: shredding, washing and drying the PET plastic waste.

[0015] As a preferred embodiment, the weight ratio of the polyester polyol to the dry-process modified waste residue plastic is 1:(1.1-1.3).

[0016] As a preferred embodiment, the temperature of the thermal curing is 30-50°C.

[0017] As a preferred embodiment, the silane diluent is (3-aminopropyl)triethoxysilane, and the isocyanate is toluene-2,4-diisocyanate.

[0018] As a preferred embodiment, when the amount of isocyanate used is 80-100 ml, the amount of zinc oxide used is 0.5-1 g, and the amount of dibutyltin dilaurate used is 0.1-0.3 g.

[0019] A polyurethane adhesive / waste residue plastic composite material obtained by the above-mentioned preparation method.

[0020] Compared with the prior art, the present invention has the following advantages and effects:

[0021] (1) Based on the original characteristics of waste plastics, the present invention uses a prepolymer method to process waste plastics into modified waste plastics, and then disperses the modified waste plastics into a polyester polyol solution. Through physical and chemical adsorption, the polyester polyol is infiltrated into the modified waste plastics, and then (3-aminopropyl) triethoxysilane is added to prevent the waste plastics from agglomerating in the polyester polyol. Toluene-2,4-diisocyanate (TDI) is added, and toluene-2,4-diisocyanate reacts with the polyester polyol in the waste plastics to be fixed together through a polymerization reaction, thereby forming a new type of organic polymer composite treatment material. The composite material has high surface smoothness and good mechanical properties, has a good effect on the large-scale production of environmentally friendly materials, and is suitable for solid waste resource treatment.

[0022] (2) The composite material of the present invention not only maintains the mechanical properties of the polyurethane adhesive, but also reduces the cost of the polyurethane adhesive / filler composite material, thereby minimizing the negative effects of PET waste and waste plastics entering the environment, solving the problem of high production costs of traditional composite materials, and effectively avoiding the harm to the environment.

[0023] (3) In the preparation method of the present invention, waste PET polyester plastic is used as raw material, which reduces the use cost of polyurethane adhesive on the one hand, and provides a highly adaptable and high-value application path for the comprehensive utilization of waste plastics on the other hand. This promotes the in-depth development and utilization of waste plastics, and provides technical support for my country to win the battle to protect the clean land and achieve sustainable development of resources and environment.

[0024] (4) The present invention uses industrial solid waste as raw material to prepare a composite material without secondary pollution. The raw material source is abundant, the preparation process is simple, the reaction conditions are relatively mild, and the process parameters are easy to control.

[0025] (5) The present invention is based on the excellent structural components of PET polyester plastic and waste residue plastic, and uses them as raw materials to prepare a composite material of polyurethane adhesive / waste residue plastic through a liquid phase solvent method. The composite material can not only utilize the good mechanical properties of PET polyester plastic, but also enhance the hardness of polyurethane adhesive / waste residue plastic, thereby reducing the production cost of the composite material and improving the high-value utilization of waste resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0027] Figure 1 This is the SEM photo of the unmodified waste plastic;

[0028] Figure 2 This is the SEM photo of the waste plastic after sawdust modification;

[0029] Figure 3 This is a SEM photograph of the polyurethane adhesive / waste residue plastic composite material prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a polyurethane adhesive / waste residue plastic composite material, which specifically comprises the following steps:

[0033] 1) Mix the waste plastic and 2 wt% of sawdust relative to the mass of the waste plastic, mix them evenly, and grind them in a high-speed grinder for 1 minute to obtain dry-process modified waste plastic;

[0034] 2) Pretreatment of waste PET plastics: Take a certain amount of waste PET plastics, cut into shreds, wash, dry and set aside.

[0035] 3) Preparation of polyester polyol: 500 g of pretreated PET polyester waste was weighed and mixed with 600 g of diethylene glycol to form a mixture, 0.3 g of catalyst zinc oxide was added to the mixture, heated to 190° C. for reaction for 5 hours, and cooled to room temperature to obtain a light yellow polyurethane adhesive prepolymer polyester polyol liquid, which was stored for later use.

[0036] 4) Preparation of polyurethane adhesive / waste residue plastic composite materials: At room temperature, 100 g of the polyester polyol obtained in step 3) and 110 g of the modified waste residue plastic obtained in step 1) were mixed in a mass ratio of 1:1.1, and then 30 mL of (3-aminopropyl) triethoxysilane was added and stirred evenly, and then 80 mL of toluene-2,4-diisocyanate (TDI) and 0.1 g of dibutyltin dilaurate were added and stirred evenly to obtain a polyurethane adhesive / waste residue plastic slurry, which was placed in a mold, vacuumed for 2 seconds, and then placed in a 30°C oven for thermal curing to obtain polyurethane adhesive / waste residue plastic composite materials with various mechanical properties.

[0037] Example 2

[0038] This embodiment provides a method for preparing a polyurethane adhesive / waste residue plastic composite material, which specifically comprises the following steps:

[0039] 1) Wash, dry and crush the collected various waste plastics, mix them evenly with 5wt% of sawdust relative to the mass of the waste plastics, and crush them in a high-speed crusher for 1 minute to obtain dry-process modified waste plastics;

[0040] 2) Pretreatment of waste PET plastics: Take a certain amount of waste PET plastics, cut into shreds, wash, dry and set aside.

[0041] 3) Preparation of polyester polyol: 500 g of pretreated PET polyester waste was weighed and mixed with 600 g of diethylene glycol to form a mixture, 0.4 g of catalyst zinc oxide was added to the mixture, heated to 200° C. for reaction for 6 hours, and cooled to room temperature to obtain a light yellow polyurethane adhesive prepolymer polyester polyol liquid, which was stored for later use.

[0042] 4) Preparation of polyurethane adhesive / waste residue plastic composite materials: At room temperature, 100 g of the polyester polyol obtained in step 3) and 120 g of the modified waste residue plastic obtained in step 1) were mixed in a mass ratio of 1:1.2, and then 40 mL of (3-aminopropyl) triethoxysilane was added and stirred evenly, and then 100 mL of toluene-2,4-diisocyanate (TDI) and 0.2 g of dibutyltin dilaurate were added and stirred evenly to obtain a polyurethane adhesive / waste residue plastic slurry, which was placed in a mold, vacuumed for 2 seconds, and then placed in a 40°C oven for thermal curing to obtain polyurethane adhesive / waste residue plastic composite materials with various mechanical properties.

[0043] Example 3

[0044] This embodiment provides a method for preparing a polyurethane adhesive / waste residue plastic composite material, which specifically comprises the following steps:

[0045] 1) Wash, dry and crush the collected various waste plastics, mix them evenly with 8.5wt% of sawdust relative to the mass of the waste plastics, and crush them in a high-speed crusher for 1 minute to obtain dry-process modified waste plastics;

[0046] 2) Pretreatment of waste PET plastics: Take a certain amount of waste PET plastics, cut into shreds, wash, dry and set aside.

[0047] 3) Preparation of polyester polyol: Weigh 500g of pretreated PET polyester waste and 600g of diethylene glycol to form a mixture, add 0.5-1g of catalyst zinc oxide to the mixture, heat to 190-220°C for reaction for 5.5 hours, cool to room temperature to obtain a light yellow polyurethane adhesive prepolymer polyester polyol liquid, and store it for later use.

[0048] 4) Preparation of polyurethane adhesive / waste residue plastic composite materials: At room temperature, 100 g of the polyester polyol obtained in step 3) and 130 g of the modified waste residue plastic obtained in step 1) were mixed in a mass ratio of 1:1.3, and then 50 mL of (3-aminopropyl) triethoxysilane was added and stirred evenly, and then 90 mL of toluene-2,4-diisocyanate (TDI) and 0.3 g of dibutyltin dilaurate were added and stirred evenly to obtain a polyurethane adhesive / waste residue plastic slurry, which was placed in a mold, vacuumed for 2 seconds, and then placed in a 50°C oven for thermal curing to obtain polyurethane adhesive / waste residue plastic composite materials with various mechanical properties.

[0049] The urethane adhesive / waste residue plastic composite materials obtained in Examples 1-3 and the separately prepared polyurethane resin were respectively tested for performance to determine the performance of the composite materials, and the results are shown in Table 1. Compared with the performance of the single polyurethane, the urethane adhesive / waste residue plastic composite material of the present invention can significantly improve the performance of the polyurethane, and can effectively avoid the negative effects caused by the waste residue plastic and PET waste plastic entering the environment.

[0050] Preparation of polyurethane adhesive / waste residue plastic composites

[0051] Comparative Example 1

[0052] The only difference between this comparative example and Example 2 is that the polyester polyol and the modified waste residue plastic are mixed in a mass ratio of 1:0.8.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 2 is that the waste residue plastic is not modified by sawdust.

[0055] Comparative Example 3

[0056] The only difference between this comparative example and Example 2 is that the polyester polyol and the modified waste residue plastic are mixed in a mass ratio of 1:1.5.

[0057] Comparative Example 4

[0058] The only difference between this comparative example and Example 2 is that the silane used is bis[3-(triethoxysilyl)propyl]-tetrasulfide.

[0059] Comparative Example 5

[0060] The only difference between this comparative example and Example 2 is that the isocyanate used is toluene-2,6-diisocyanate.

[0061] The SEM images of the unmodified waste plastic and the waste plastic modified with sawdust are shown in Figure 2. Figure 1 and 2 As shown, the unmodified waste plastic is in the form of irregular block particles with large flakes on the surface, while the surface of the waste plastic modified with sawdust is fluffy. This is because after being modified with sawdust, the waste plastic is not easy to agglomerate and is easy to penetrate and mix with polyester polyol.

[0062] By comparing Example 2 with Comparative Example 2, combined with Table 1, it can be seen that when the unmodified waste plastic and the modified waste plastic are used to prepare the composite material, the waste plastic particles that have not been dry-modified are larger, resulting in a low degree of fusion, which will greatly affect the integrity of the polyurethane composite board and the uniformity of the reaction of polyester polyol and TDI, resulting in poor overall mechanical properties of the composite material. Since the waste plastic is dry-modified with sawdust, its internal surface is doped with sawdust, resulting in the waste plastic not agglomerating during the dry crushing process, forming fine powder, which is conducive to the full mixing reaction of the two components of the polyurethane, such as Figure 3As shown. It can be seen from Examples 1 to 3 that the mechanical properties of the polyurethane / waste residue plastic composite material increase with the increase of the addition amount of the modified waste residue plastic and the sawdust. When the addition amount of sawdust is 5%, the mechanical properties of the composite material reach the best. Therefore, the waste residue plastic with a sawdust addition amount of 5% is selected; by comparing the reaction of toluene-2,4-diisocyanate (TDI) and toluene-2,6-diisocyanate (TDI) with polyester polyols, it is found that due to the structure of toluene-2,6-diisocyanate (TDI) itself, it is difficult for isocyanate to react well with polyester polyols due to the steric hindrance effect. Therefore, toluene-2,4-diisocyanate (TDI) is selected to react with polyester polyols containing modified waste residue plastics. When selecting silane as a diluent, a comparison was made between bis[3-(triethoxysilyl)propyl]tetrasulfide and (3-aminopropyl)triethoxysilane. The results showed that the mechanical properties of (3-aminopropyl)triethoxysilane as a diluent in the synthesis of polyurethane adhesive / waste residue plastic composites were better than those of bis[3-(triethoxysilyl)propyl]tetrasulfide as a diluent in the synthesis, which may be determined by the different structures of the silanes themselves.

[0063] Table 1 Performance of different composite materials

[0064]

[0065] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a polyurethane adhesive / waste residue plastic composite material, characterized in that: The steps include: preparing dry-process modified waste residue plastics and polyester polyols respectively; After the polyester polyol and the dry-modified waste residue plastic are mixed, a silane diluent is added, mixed, and then isocyanate and dibutyltin dilaurate are added, stirred evenly to obtain a polyurethane adhesive / waste residue plastic slurry, shaped, and heat-cured in a vacuum to obtain the polyurethane adhesive / waste residue plastic composite material; The preparation method of the dry modified waste residue plastic is: The waste plastic is washed, dried and crushed, then mixed evenly with sawdust, and crushed again to obtain dry-modified waste plastic; The amount of sawdust added is 5% of the weight of the waste plastic; The weight ratio of the polyester polyol to the dry modified waste plastic is 1:(1.1-1.3); The silane diluent is (3-aminopropyl)triethoxysilane, and the isocyanate is toluene-2,4-diisocyanate.

2. The method for preparing the polyurethane adhesive / waste residue plastic composite material according to claim 1, characterized in that: The preparation method of the polyester polyol is: The pretreated PET waste and diethylene glycol are mixed in a weight ratio of 1:2, zinc oxide is added, and the mixture is reacted at 190-220° C. to obtain polyester polyol.

3. The method for preparing the polyurethane adhesive / waste residue plastic composite material according to claim 2, characterized in that: The pretreatment method of the PET waste is: shredding, washing and drying the PET plastic waste.

4. The method for preparing the polyurethane adhesive / waste residue plastic composite material according to claim 1, characterized in that: The temperature of the thermal curing is 30-50°C.

5. The method for preparing the polyurethane adhesive / waste residue plastic composite material according to claim 1, characterized in that: When the dosage of isocyanate is 80~100ml, the dosage of zinc oxide is 0.5~1g, and the dosage of dibutyltin dilaurate is 0.1~0.3g.

6. A polyurethane adhesive / waste residue plastic composite material obtained by the preparation method as claimed in claim 1.

Images