CN115011071A

CN115011071A - SMC composite material and preparation method thereof

Info

Publication number: CN115011071A
Application number: CN202210725034.1A
Authority: CN
Inventors: 石绍迁; 梅汇锋; 张彦彪; 王清国; 乔小兵
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2022-09-06

Abstract

The invention relates to an SMC composite material and a preparation method thereof. The SMC composite material comprises the following components in parts by weight: 90-120 parts of epoxy resin, 30-50 parts of curing agent, 5-10 parts of thickening agent, 50-120 parts of biomass carbon filler and 400 parts of chopped carbon fiber 250-one. According to the invention, the carbon fiber is used as a reinforcing material, compared with the traditional glass fiber reinforced SMC composite material, the mechanical property of an SMC product can be greatly improved, the biomass carbon is used as a filler, the density of the carbon fiber SMC composite material can be effectively reduced, the formability is improved by adding the thickening agent, and the SMC composite material has good mechanical property and formability on the basis of low density through the short carbon fiber, the epoxy resin, the curing agent, the thickening agent and the biomass carbon filler in a specific proportion.

Description

SMC composite material and preparation method thereof

Technical Field

The invention relates to the technical field of composite materials, in particular to an SMC composite material and a preparation method thereof.

Background

The research and development of novel light high-strength materials are important development directions of the automobile material industry, and the development and research of fiber reinforced composite materials are important. SMC composite materials are widely used in automobile manufacturing because of their advantages such as good formability, paintability, specific strength, etc.

SMC composites are generally composed of reinforcing fibers, a resin matrix, a curing agent, various types of adjuvants and fillers. At present, calcium carbonate, kaolin, talcum powder and the like are generally used as fillers for SMC composite materials, however, the density of the materials is improved, and the weight reduction of the SMC composite materials is not facilitated.

Disclosure of Invention

Accordingly, there is a need for a SMC composite having low density and good mechanical properties and a method for preparing the same.

One object of the present invention is to provide an SMC composite, the scheme being as follows:

the SMC composite material comprises the following components in parts by weight:

in one embodiment, the biomass charcoal filler is prepared by a method comprising the following steps:

carbonizing the biomass material at 600-1000 ℃ to obtain a carbonized product;

and soaking the carbonized product by adopting a silane coupling agent.

In one embodiment, the biomass material is selected from at least one of rice hulls, straw, husks, and seaweed.

In one embodiment, the silane coupling agent is selected from at least one of KH550, KH560 and KH 570.

In one embodiment, the carbonization treatment is performed by hydrothermal carbonization, laser-induced carbonization, or microwave-assisted carbonization.

In one embodiment the carbon content of the carbonized product is 40% to 50%.

In one embodiment, the biomass charcoal filler has a particle size of 20 μm to 35 μm.

In one embodiment, the density of the biomass charcoal filler is 0.9g/cm ³ -1.2g/cm ³ 。

In one embodiment, the chopped carbon fibers are selected from at least one of T300, T400, T600 and T700 carbon fibers.

In one embodiment the chopped carbon fibres have a fibre length of from 15mm to 35 mm.

In one embodiment, the epoxy resin is at least one selected from the group consisting of a glycidyl ether type epoxy resin, a cycloaliphatic epoxy resin, and a modified epoxy resin selected from at least one of a urethane-modified epoxy resin and a vinyl-modified epoxy resin.

The curing agent is at least one selected from dicyandiamide, aromatic amine, ethylenediamine, phthalic anhydride and diaminodiphenylmethane.

In one embodiment the thickener is MgO, Mg (OH) ₂ CaO and Ca (OH) ₂ At least one of (1).

In one embodiment, the SMC composite further comprises 1-5 parts by weight of an internal mold release agent.

In one embodiment, the internal mold release agent is selected from at least one of zinc stearate and calcium stearate.

It is still another object of the present invention to provide a method for preparing the SMC composite of any one of the above embodiments, wherein the scheme is as follows:

a preparation method of the SMC composite material comprises the following steps:

adding the epoxy resin and the curing agent into a container, and uniformly stirring to obtain a first mixture;

adding the biomass charcoal filler into the first mixture while stirring, adding the biomass charcoal filler for multiple times, and continuously stirring uniformly to obtain a second mixture;

when the second mixture is stirred until the temperature rises to 30-45 ℃, adding the thickening agent, and continuing stirring until the viscosity reaches 28000-32000 cP to obtain a third mixture;

adding the chopped carbon fibers into the third mixture to obtain a prepreg;

curing the prepreg at 40-50 ℃ to obtain a cured prepreg;

and carrying out compression molding on the cured prepreg to obtain the SMC composite material.

Compared with the traditional scheme, the SMC composite material and the preparation method thereof have the following beneficial effects:

the SMC composite material and the preparation method thereof adopt the carbon fiber as the reinforcing material, compared with the traditional glass fiber reinforced SMC composite material, the mechanical property of an SMC product can be greatly improved, the biomass carbon is adopted as the filler, the density of the carbon fiber SMC composite material can be effectively reduced, the formability is improved by adding the thickening agent, and the SMC composite material has good mechanical property and formability on the basis of low density by using the short carbon fiber, the epoxy resin, the curing agent, the thickening agent and the biomass carbon filler in a specific proportion.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The SMC composite material provided by the embodiment of the invention comprises the following components in parts by weight:

the SMC composite material has the following advantages:

the biomass carbon material can greatly reduce the density of the SMC composite material, and the SMC composite material has good mechanical property and formability on the basis of low density through the chopped carbon fibers, the epoxy resin, the curing agent, the thickening agent and the biomass carbon filler in a specific ratio.

2, the biomass carbon material has the advantages of wide source, low raw material price, reproducibility, easy processing, adjustable surface performance and the like, and can improve the resource utilization rate.

3, the problem of uneven surface color of SMC products caused by traditional calcium carbonate and other fillers can be solved.

Compared with a continuous carbon fiber reinforced composite material, the SMC composite material has better manufacturability and formability and improves the production efficiency.

Preferably, the SMC composite material comprises the following components in parts by weight:

in one example, the biomass charcoal filler is prepared by a method comprising the following steps:

the biomass material is carbonized at 600-1000 ℃ to obtain a carbonized product.

And (3) soaking the carbonized product by adopting a silane coupling agent.

Through the soaking treatment of the silane coupling agent, the product has hydrophobicity and lipophilicity, and the compatibility with a high molecular polymer is improved.

Optionally, the silane coupling agent is selected from at least one of KH550, KH560 and KH 570.

In one example, the preparation method further comprises the step of screening and impurity removing treatment on the biomass material before the carbonization treatment.

Optionally, the biomass material is selected from at least one of rice hulls, straw, husks, and seaweed.

Optionally, the carbonization treatment is performed by hydrothermal carbonization, laser-induced carbonization, or microwave-assisted carbonization.

In one example, the carbon content of the carbonized product is 40% -50%.

In one example, the biomass charcoal filler has a particle size of 20 μm to 35 μm.

In one example, the biomass charcoal filler has a density of 1.05g/cm ³ -1.25g/cm ³ 。

Optionally, the chopped carbon fibers may be selected from, but are not limited to, at least one of T300, T400, T600, and T700 carbon fibers.

In one example, the chopped carbon fibers have a fiber length of 15mm to 35mm, specifically, for example, 15nm, 20mm, 25mm, 30mm, 35mm, and the like.

In one example, the chopped carbon fibers are surface treated with a silane coupling agent. Optionally, the silane coupling agent is selected from at least one of KH550, KH560 and KH 570.

Alternatively, the epoxy resin may be selected from, but not limited to, at least one of a glycidyl ether type epoxy resin, a cycloaliphatic epoxy resin, and a modified epoxy resin. The modified epoxy resin may be, for example, a urethane-modified epoxy resin, a vinyl-modified epoxy resin, or the like.

Alternatively, the curing agent may be selected from, but not limited to, at least one of dicyandiamide, aromatic amine, ethylenediamine, phthalic anhydride, and diaminodiphenylmethane.

Alternatively, the thickener may be selected from, but not limited to, MgO, Mg (OH) ₂ CaO and Ca (OH) ₂ At least one of (1).

In one example, the SMC composite also contains an internal mold release agent, which may facilitate demolding after molding. In one example, the internal mold release agent is present in an amount of 1 to 5 parts by weight.

Alternatively, the internal mold release agent may be selected from, but not limited to, at least one of zinc stearate and calcium stearate.

Further, the present invention also provides a method for preparing any of the above-described exemplary SMC composites, comprising the steps of:

and step S1, adding the epoxy resin and the curing agent into a container, and uniformly stirring to obtain a first mixture.

In one example, the stirring speed is 800r/min-1000 r/min. The stirring time is 1min-2 min.

And step S2, adding the biomass charcoal filler into the first mixture while stirring, adding the biomass charcoal filler for multiple times, and continuously stirring uniformly to obtain a second mixture.

In one example, the stirring speed is 1000r/min-1200 r/min. After the biomass carbon filler is completely added, the rotating speed is kept for 5min to 8min, so that the materials of all components are uniformly distributed and the caking phenomenon is avoided.

And step S3, adding the thickening agent after the temperature of the second mixture is stirred to be increased to 30-45 ℃, continuing stirring until the viscosity reaches 28000-32000 cP, and stopping stirring to obtain a third mixture.

And step S4, adding the chopped carbon fibers into the third mixture to obtain a prepreg.

In one example, the step of adding chopped carbon fibers to the third mix comprises: and coating the third mixture on a bearing film, sprinkling the short carbon fibers on the third mixture to enable the third mixture to fully infiltrate the short carbon fibers, and rolling to discharge air bubbles to obtain the prepreg.

In one example, the step of adding chopped carbon fibers to the third mix comprises: and laying the chopped carbon fibers on a carrier film, impregnating the chopped carbon fibers with a third mixture, and rolling to discharge air bubbles to obtain the prepreg.

In one example, the carrier film is a polyethylene film.

And step S5, curing the prepreg at the temperature of 40-50 ℃ to obtain the cured prepreg.

In one example, the material is cured to a tack-free state.

And step S6, performing compression molding on the cured prepreg to obtain the SMC composite material.

In one example, when compression molding is carried out, prepreg can be placed when the temperature of a female die of a mold is 135-145 ℃ and the temperature of a male die reaches 140-150 ℃, the pressure is set to be 2-4MPa, the pressure is maintained for 50-80 s, and demolding is carried out.

In one example, the SMC composite also contains an internal mold release agent that may facilitate demolding after molding. The internal mold release agent may be stirred with the epoxy resin and the curing agent added in step S1 described above. Preferably, the epoxy resin, curing agent and internal mold release agent are added sequentially.

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.

The biomass charcoal filler in the following examples is prepared by the following preparation method:

carbonizing the biomass material at 700 ℃ to obtain a carbonized product. And (3) crushing, winnowing and grading the carbonized product, soaking the carbonized product in a silane coupling agent KH560 after the particle size ranges from 20 micrometers to 35 micrometers, and carrying out surface modification.

The biomass charcoal filler A adopts straws as a biomass material, the biomass charcoal filler B adopts rice hulls as a biomass material, the biomass charcoal filler C adopts shells as a biomass material, and the biomass charcoal filler D adopts seaweed as a biomass material.

Example 1

The SMC composite of this example contains the following components in parts by weight:

the preparation method of the SMC composite of this example includes the following steps:

step 1, putting all powdery solids in the experimental drug into a vacuum drying oven, drying for 12h at 80 ℃, and then cooling to room temperature in the drying oven.

And 2, performing surface treatment on the chopped carbon fibers by using a silane coupling agent KH570 and the like.

And 3, adding the epoxy resin, the curing agent and the internal release agent into a container, and stirring for 60s at 950r/min to obtain a first mixture.

And 4, increasing the stirring speed to 1150r/min, adding a small amount of biomass charcoal filler into the first mixture for multiple times, and continuously stirring for 6min to obtain a second mixture.

And 5, when the second mixture is stirred until the temperature rises to 35 ℃, adding the thickening agent, and continuously stirring at the rotating speed of 1300r/min for 10min to obtain a third mixture.

And 6, respectively placing the two polyethylene films on two flat plates, laying the short carbon fibers on the polyethylene films, impregnating the short carbon fibers with the prepared third mixture, and then repeatedly rolling by using a wood bar to remove bubbles in the short carbon fibers.

Example 2

And 2, performing surface treatment on the chopped carbon fibers by using a silane coupling agent KH550 and the like.

And 3, adding the epoxy resin, the curing agent and the internal release agent into a container, and stirring for 60s at 900r/min to obtain a first mixture.

And 4, increasing the stirring speed to 1180r/min, adding a small amount of biomass charcoal filler into the first mixture for multiple times, and continuously stirring for 7min to obtain a second mixture.

And 5, when the temperature of the second mixture is stirred to rise to 35 ℃, adding the thickening agent, and continuously stirring at the rotating speed of 1240r/min for 11min to obtain a third mixture.

And 6, respectively placing the two polyethylene films on two flat plates, laying the chopped fiber filaments on the polyethylene films, impregnating the chopped carbon fibers with the prepared third mixture, and then repeatedly rolling by using a wood bar to remove bubbles in the chopped carbon fibers.

And 7, rolling the sheet, putting the rolled sheet into an oven with the temperature of 45 ℃, and carrying out compression molding on the sheet after 4 days. The temperature of the forming die is 155 ℃, the pressure is 2MPa, and the pressure maintaining time is 48 s. And demolding to obtain the SMC composite material.

Example 3

And 2, performing surface treatment on the chopped carbon fibers by using a silane coupling agent KH560 and the like.

And 3, adding the epoxy resin, the curing agent and the internal release agent into a container, and stirring for 60s at 850r/min to obtain a first mixture.

And 4, increasing the stirring speed to 1200r/min, adding a small amount of biomass charcoal filler into the first mixture for multiple times, and continuously stirring for 7min to obtain a second mixture.

And 5, when the second mixture is stirred until the temperature rises to 35 ℃, adding the thickening agent, and continuously stirring at the rotating speed of 1300r/min for 11min to obtain a third mixture.

Example 4

Example 5

wherein, the biomass charcoal is filled with

Example 6

Comparative example 1

The SMC composite material of the comparative example comprises the following components in parts by weight:

the method of making the SMC composite of this comparative example includes the steps of:

step 1, putting all powdery solids in the experimental drug into a vacuum drying oven, drying for 12 hours at 80 ℃, and then cooling to room temperature in the drying oven.

And 6, respectively placing the two polyethylene films on two flat plates, laying the chopped glass fibers on the polyethylene films, soaking the chopped glass fibers in the prepared third mixture, and then repeatedly rolling by using a wood bar to remove bubbles in the chopped glass fibers.

Comparative example 2

And 4, adding the thickening agent into the first mixture, and continuously stirring at the rotating speed of 1300r/min for 10min to obtain a second mixture.

And 5, respectively placing the two polyethylene films on two flat plates, laying the chopped fiber filaments on the polyethylene films, impregnating the chopped carbon fibers with the prepared second mixture, and then repeatedly rolling by using a wood bar to remove bubbles in the chopped carbon fibers.

And step 6, rolling the sheet, putting the rolled sheet into an oven with the temperature of 45 ℃, and carrying out compression molding on the sheet after 4 days. The temperature of the forming die is 155 ℃, the pressure is 2MPa, and the pressure maintaining time is 48 s. And demolding to obtain the SMC composite material.

Comparative example 3

And step 6, respectively placing the two polyethylene films on the two flat plates, laying the short carbon fibers on the polyethylene films, impregnating the short carbon fibers with the prepared third mixture, and then repeatedly rolling by using a wood bar to remove air bubbles in the short carbon fibers.

The SMC composites prepared in examples 1-6 and comparative examples 1-3 were tested for density, flexural strength and tensile strength. The density was tested according to standard GB/T1463-. The bending strength was tested according to the standard GB/T1449-. The tensile strength was tested in accordance with standard GB/T1451-. The results of the performance tests are shown in table 1.

TABLE 1 SMC composite Performance test results

From the above results, it can be seen that the SMC composite materials prepared in examples 1-6 have lower density and good bending strength and tensile strength compared with comparative examples 1-3.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims, and the description can be used to interpret the contents of the claims.

Claims

1. The SMC composite material is characterized by comprising the following components in parts by weight:

2. the SMC composite of claim 1, wherein the biomass char filler is prepared by a method comprising the steps of:

and soaking the carbonized product by adopting a silane coupling agent.

3. An SMC composite as in claim 2 wherein the biomass material is selected from at least one of rice hulls, straw, husks and seaweed; and/or

The silane coupling agent is at least one selected from KH550, KH560 and KH 570.

4. An SMC composite material as in claim 2 wherein the carbonization treatment is by hydrothermal carbonization, laser-induced carbonization or microwave-assisted carbonization; and/or

The carbon content of the carbonized product is 40-50%.

5. An SMC composite according to any of claims 1-4, wherein the biomass char filler has a particle size of 20 μm to 35 μm; and/or

The density of the biomass charcoal filler is 0.9g/cm ³ -1.2g/cm ³ 。

6. SMC composite material according to any of claims 1-4, characterized in that the chopped carbon fibres are selected from at least one of T300-, T400-, T600-and T700-type carbon fibres; and/or

The length of the chopped carbon fiber is 15mm-35 mm.

7. An SMC composite according to any of claims 1-4, wherein the epoxy resin is selected from at least one of a glycidyl ether type epoxy resin, a cycloaliphatic epoxy resin, and a modified epoxy resin selected from at least one of a polyurethane modified epoxy resin and a vinyl modified epoxy resin; and/or

The curing agent is at least one selected from dicyandiamide, aromatic amine, ethylenediamine, phthalic anhydride and diaminodiphenylmethane; and/or

The thickener is MgO, Mg (OH) ₂ CaO and Ca (OH) ₂ At least one of (1).

8. SMC composite according to any of claims 1-4, characterized in that the SMC composite further comprises 1-5 parts by weight of an internal mould release agent.

9. An SMC composite as in claim 8, wherein said internal release agent is selected from at least one of zinc stearate and calcium stearate.

10. A method of making an SMC composite as in any one of claims 1 to 9 comprising the steps of:

adding the chopped carbon fibers into the third mixture to obtain a prepreg;

curing the prepreg at 40-50 ℃ to obtain a cured prepreg;