Preparation method of regenerated BMC (bulk molding compound)

Abstract

The invention relates to the field of BMC molding compound production, in particular to a preparation method of a regenerated BMC molding compound. The method comprises the following steps: (1) granulating the waste molding compound, and crushing by using a particle crusher to obtain 80-120-mesh particles and powder of a prepared product; (2) grinding the powder by using a spherical grinding machine, and adding a surfactant and zinc stearate powder in the grinding process for surface treatment to reduce the surface tension of the powder, so as to reduce the oil absorption rate and obtain particles of 400 + / -20 meshes and particles of 800 + / -20 meshes of a prepared product; (3) stirring unsaturated polyester resin / low-shrinkage resin / curing agent / inhibitor by using a dispersion machine; (4) adding the materials obtained in the step (3) into a kneading machine, adding zinc stearate and the prepared 80-120-mesh particles, the prepared 400 + / -20-mesh particles and the prepared 800 + / -20-mesh particles, and kneading and stirring the materials and the prepared 80-120-mesh particles, the prepared 400 + / -20-mesh particles and the prepared 800 + / -20-mesh particles; and (5) adding glass fibers, kneading and stirring to obtain the BMC molding compound.

Description

Technical Field

[0001] The invention relates to the field of BMC molding compound production, and specifically provides a preparation method of recycled BMC molding compound. Background Art

[0002] In today's rapidly developing industrial society, the continuous progress of materials science and technology has brought unprecedented innovation and breakthroughs to various industries. Among them, BMC molding compounds, as a unique semi-dry molding intermediate material for manufacturing glass fiber reinforced thermosetting products, have been widely used in many fields such as automotive parts, electrical and electronic components, and building decoration materials due to their excellent physical properties, corrosion resistance, and good processing performance. However, with the continuous expansion and upgrading of these fields, the amount of waste BMC molding compounds generated each year is also increasing, which is not only a huge waste of resources, but also a potential threat to the environment. Therefore, the recycling and reuse of waste BMC molding compounds has become an important issue that needs to be solved urgently.

[0003] The recycling and reuse of waste BMC molding materials not only helps to alleviate the pressure of resource shortage and reduce environmental pollution, but also brings significant economic benefits to enterprises. By improving the recycling rate and utilization rate of waste materials, enterprises can reduce the cost of raw materials. Summary of the invention

[0004] The present invention hopes to provide a method for preparing recycled BMC molding compound, and the specific scheme is as follows:

[0005] A method for preparing a recycled BMC molding compound comprises the following steps:

[0006] (1) Granulating the waste molding plastic, and crushing it with a granulator to obtain 80-120 mesh granules and powders of the preparation;

[0007] (2) grinding the powder using a ball mill, adding a surfactant and zinc stearate powder for surface treatment during the grinding process to reduce the surface tension of the powder, thereby reducing the oil absorption rate, and obtaining 400±20 mesh particles of the preparation and 800±20 mesh particles of the preparation;

[0008] (3) unsaturated polyester resin / low shrinkage resin / curing agent / inhibitor are stirred using a disperser; (4) the material obtained in step (3) is added to a kneader, and zinc stearate and the prepared 80-120 mesh particles, the prepared 400±20 mesh particles and the prepared 800±20 mesh particles are added at the same time, and kneaded and stirred;

[0009] (5) Add glass fiber, knead and stir to obtain BMC molding compound.

[0010] The ball mill complies with the following formula,

[0011]

[0012] Where D is the discharge mesh size, t is the grinding time, n is the molding material index, V is the effective volume of the ball mill, H is the hardness of the ball milling medium, B is the size of the ball milling medium, and a and b are empirical indices, which are determined by computer fitting.

[0013] The surfactant in step (2) is HK-550 silane coupling agent.

[0014] The material ratio is as follows: unsaturated polyester resin 13-15%; low shrinkage resin 7-9%; zinc stearate 1-2%; prepared 80-120 mesh particles 13-17%; prepared 400±20 mesh particles 23-27%; prepared 800±20 mesh particles 26-29%; curing agent 0.3-08%; inhibitor 0.2-0.5%; glass fiber 5-9%.

[0015] The material ratio is as follows: unsaturated polyester resin 14%; low shrinkage resin 8%; zinc stearate 1.6%; prepared 80-120 mesh particles 15%; prepared 400±20 mesh particles 25%; prepared 800±20 mesh particles 28.6%; curing agent 0.5%; inhibitor 0.3%; glass fiber 7%.

[0016] In the step (4), the kneading machine includes a shell and a top cover, the top cover is provided with a stirring motor, a rotating shaft is provided at one end of the stirring motor, an inner stirring spiral and an outer stirring spiral are provided on the rotating shaft, and the spacing between adjacent threads in the inner stirring spiral is smaller than the spacing between adjacent threads in the outer stirring spiral.

[0017] The shell and the top cover are connected in a detachable manner.

[0018] A molding mechanism is provided at the bottom of the shell.

[0019] The present invention has the following advantages:

[0020] 1. The present invention optimizes the particles of the prepared product (i.e., waste BMC molding compound) with different particle sizes. This is because different particles have different oil absorption rates, and the granular form of the present invention can increase the molding cavity pressure.

[0021] 2. The present invention first granulates and then grinds, and can directly obtain 80-120 mesh particles of the prepared product. At the same time, the obtained powder is further ground, and the granulation (granules can increase the pressure of the molding cavity) and the preparation of large particles are completed at the same time, and a basis is provided for further grinding of the particles in the next step.

[0022] 3. The formula of the ball mill of the present invention can determine the processing time of the ball mill to process particles of corresponding mesh size.

[0023] 4. The present invention adds HK-550 silane coupling agent and zinc stearate powder for surface treatment to reduce the surface tension of the powder, thereby reducing the oil absorption rate.

[0024] 5. Compared with the traditional desktop kneading machine, the kneading machine of the present invention discharges materials faster and directly performs shaping, which is highly efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of a kneading machine used in a method for preparing a recycled BMC molding compound according to the present invention;

[0026] Figure 2 A partial structural schematic diagram of a kneading machine used in a method for preparing a recycled BMC molding compound according to the present invention;

[0027] The numbers are as follows: 1. Shell; 2. Top cover; 3. Stirring motor; 4. Rotating shaft; 5. Inner stirring spiral; 6. Outer stirring spiral; 7. Molding mechanism. DETAILED DESCRIPTION

[0028] Example 1

[0029] A method for preparing a recycled BMC molding compound comprises the following steps:

[0030] (1) Granulating the waste molding plastic, and crushing it with a granulator to obtain 80-120 mesh granules and powders of the preparation;

[0031] (2) grinding the powder using a ball mill, adding a surfactant and zinc stearate powder for surface treatment during the grinding process to reduce the surface tension of the powder, thereby reducing the oil absorption rate, and obtaining 400±20 mesh particles of the preparation and 800±20 mesh particles of the preparation;

[0032] (3) unsaturated polyester resin / low shrinkage resin / curing agent / inhibitor are stirred using a disperser; (4) the material obtained in step (3) is added to a kneader, and zinc stearate and the prepared 80-120 mesh particles, the prepared 400±20 mesh particles and the prepared 800±20 mesh particles are added at the same time, and kneaded and stirred;

[0033] (5) Add glass fiber, knead and stir to obtain BMC molding compound.

[0034] The ball mill meets the following formula,

[0035]

[0036] Where D is the discharge mesh size, t is the grinding time, n is the molding material index, V is the effective volume of the ball mill, H is the hardness of the ball milling medium, B is the size of the ball milling medium, and a and b are empirical indices, which are determined by computer fitting.

[0037] In practice, D, n, V, H and B are known, and ab can be determined by computer fitting, which may be different for different equipment and environmental conditions.

[0038] The surfactant in step (2) is HK-550 silane coupling agent.

[0039] The quality of specific materials added is as follows:

[0040]

[0041] In step (4), the kneading machine includes a shell 1 and a top cover 2, the top cover 2 is provided with a stirring motor 3, a rotating shaft 4 is provided at one end of the stirring motor 3, an inner stirring spiral 5 and an outer stirring spiral 6 are provided on the rotating shaft 4, the spacing between adjacent threads in the inner stirring spiral 5 is smaller than the spacing between adjacent threads in the outer stirring spiral 6, the shell 1 and the top cover 2 are detachably connected, and a molding mechanism 7 is provided at the bottom of the shell 1 (the molding mechanism is used to shape the BMC molding material into a rectangular parallelepiped shape for convenience of later processing).

[0042] The experimental data of Example 1 are as follows:

[0043]

[0044] Examples 2-7 (The following examples are used to illustrate the effect of particle size on the product)

[0045] The other data of Example 2-10 are the same as those of Example 1, except for the following data, which are detailed in the table:

[0046]

[0047]

[0048] Examples 11-13

[0049] The other data of Examples 11-13 are the same as those of Example 1, except for the following data, which are detailed in the table:

[0050]

[0051]

[0052] The above content describes the technical principles, beneficial effects and features of the present invention. It should be pointed out that the above is only a preferred implementation mode of the present invention, but is not limited to the above embodiments. For technicians in the technical field to which the present invention belongs, some improvements and optimizations can be made without departing from the content of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing a recycled BMC molding compound, characterized in that: The steps include: Granulate the waste molding plastic, crush it with a particle crusher, and obtain 80-120 mesh particles and powder of the preparation; The powder is ground using a ball mill, and during the grinding process, a surfactant and zinc stearate powder are added for surface treatment to reduce the surface tension of the powder, thereby reducing the oil absorption rate, and obtaining 400±20 mesh particles of the preparation and 800±20 mesh particles of the preparation; Unsaturated polyester resin / low shrinkage resin / curing agent / inhibitor, stirred using a disperser; Add the material obtained in step (3) into a kneader, and add zinc stearate and the prepared 80-120 mesh granules, the prepared 400±20 mesh granules and the prepared 800±20 mesh granules, and knead and stir; Add glass fiber, knead and stir to obtain BMC molding compound.

2. The method for preparing a recycled BMC molding compound according to claim 1, characterized in that: The ball mill complies with the following formula, Where D is the discharge mesh size, t is the grinding time, n is the molding material index, V is the effective volume of the ball mill, H is the hardness of the ball milling medium, B is the size of the ball milling medium, and a and b are empirical indices, which are determined by computer fitting.

3. The method for preparing a recycled BMC molding compound according to claim 1, characterized in that: The surfactant in step (2) is HK-550 silane coupling agent.

4. The method for preparing a recycled BMC molding compound according to claim 1, characterized in that: The material ratio is as follows: unsaturated polyester resin 13-15%; low shrinkage resin 7-9%; zinc stearate 1-2%; prepared 80-120 mesh particles 13-17%; prepared 400±20 mesh particles 23-27%; prepared 800±20 mesh particles 26-29%; curing agent 0.3-08%; inhibitor 0.2-0.5%; glass fiber 5-9%.

5. The method for preparing a recycled BMC molding compound according to claim 4, characterized in that: The material proportions are as follows: unsaturated polyester resin 14%; low shrinkage resin 8%; zinc stearate 1.6%; prepared 80-120 mesh particles 15%; prepared 400±20 mesh particles 25%; prepared 800±20 mesh particles 28.6%; curing agent 0.5%; inhibitor 0.3%; glass fiber 7%.

6. The method for preparing a recycled BMC molding compound according to claim 1, characterized in that: In step (4), the kneading machine comprises a shell and a top cover, the top cover is provided with a stirring motor, one end of the stirring motor is provided with a rotating shaft, the rotating shaft is provided with an inner stirring spiral and an outer stirring spiral, and the spacing between adjacent threads in the inner stirring spiral is smaller than the spacing between adjacent threads in the outer stirring spiral.

7. The method for preparing a recycled BMC molding compound according to claim 1, characterized in that: The shell and the top cover are connected in a detachable manner.

8. The method for preparing a recycled BMC molding compound according to claim 1, characterized in that: A molding mechanism is provided at the bottom of the shell.

Images