KR20200081836A - Hollow filler for sheet molding compound and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a hollow filler for SMC, which can be chemically bonded at an interface with a matrix resin forming SMC, and a method of manufacturing the same. The hollow filler for SMC according to an embodiment of the present invention relates to a hollow filler mixed with SMC formed by impregnating a matrix resin having a double bond structure in a reinforcing fiber, and comprises: a filler body formed with a hollow inside; and a coating layer which is formed by being coated on a surface of the filler body, and formed of a coating agent having a double bond structure at the end so as to be chemically bonded to the matrix resin.

Description

Hollow filler for SMC and manufacturing method thereof

The present invention relates to a hollow filler for SMC and a method for manufacturing the same, and more particularly, to a hollow filler for SMC capable of chemically bonding at an interface with a matrix resin forming SMC and a method for manufacturing the same.

SMC (Sheet Molding Compound) is a composite material produced in the form of a sheet by dispersing glass short fibers and the like into a sheet body made of a thermosetting resin and then pressure-molding it. SMC is a sheet-shaped composite molding material with no adhesiveness and excellent moldability, and is widely used for architectural and automotive applications.

As these SMCs are used for various purposes, the demand for low specific gravity SMCs has increased.

In general, in order to manufacture a low specific gravity SMC, a method of mixing a hollow filler with a matrix resin such as a thermosetting resin forming SMC is used.

However, when the hollow filler is mixed with the SMC, although an effect of reducing the specific gravity of the SMC can be obtained, a decrease in physical properties corresponding thereto occurs.

In other words, the hollow filler exists in a physically dispersed state without chemical bonding with the mattress resin in the matrix resin forming the SMC. In this case, the dispersion degree of the hollow filler varies for each product, resulting in uniform product quality. There was a problem that the sex decreased.

In addition, there was also a problem that the rigidity of the SMC was lowered while an interface was generated between the hollow filler and the matrix resin.

The content described as the above background technology is only for understanding the background of the present invention, and should not be taken as an admission that it corresponds to the prior art already known to those skilled in the art.

Patent Publication No. 10-2012-0134830 (2012.12.12)

The present invention provides a hollow filler for SMC and a method for manufacturing the same, which can maintain excellent strength while achieving weight reduction of SMC by chemically bonding at the interface with a matrix resin forming SMC.

A hollow filler for SMC according to an embodiment of the present invention is a hollow filler mixed in SMC formed by impregnating a matrix resin having a double bond structure in a reinforcing fiber, and a filler body having a hollow formed therein; It is formed by coating on the surface of the filler body, it is characterized in that it consists of a coating layer formed of a coating agent having a double bond structure at the end to be chemically bonded to the matrix resin.

The filler body is characterized by consisting of at least one of soda lime glass (soda lime glass) and borosilicate glass (borosilicate glass).

The coating agent is characterized in that it is at least one of 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane and Trimethoxy(4-vinylphenyl)silane.

The coating agent is a hollow filler for SMC, characterized in that at least one of the low-molecular materials represented by the following [Formula 1] to [Formula 3].

[Formula 1]

[Formula 2]

[Formula 3]

On the other hand, the method for manufacturing a hollow filler for SMC according to an embodiment of the present invention is a method for manufacturing a hollow filler mixed in SMC formed by impregnating a matrix resin having a double bond structure in a reinforcing fiber. A filler body preparation step of preparing the formed filler body; A coating liquid preparation step of preparing a coating liquid having a double bond structure at the terminal so that it can be chemically combined with the matrix resin; And a coating step of coating the prepared coating solution on the surface of the filler body.

The filler body preparation step is characterized in that the inside of the filler body is molded using at least one of soda lime glass and borosilicate glass.

The coating solution preparation step, a diluent preparation process for adjusting the pH of the diluent; It is characterized by consisting of a hydrolysis process to prepare a coating solution by adding a coating agent to a pH-adjusted diluent and hydrolyzing.

In the preparation of the diluent, the diluent is characterized by using an alcohol diluent and mixing the pH adjusting agent with the diluent for pH adjustment.

The coating agent used in the hydrolysis process is characterized in that the coating agent is at least one of 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane and Trimethoxy(4-vinylphenyl)silane. .

The coating step, a stirring process for putting the prepared filler body into the stirrer and stirring while applying heat; A spray coating process of coating the coating solution on the surface of the filler body by spraying the prepared coating solution while stirring the heated filler body; It is characterized in that it consists of a diluent removal process to remove the diluent of the coating solution by heat-treating the filler body coated with the coating solution on the surface.

The spray coating process is characterized in that it is carried out while stirring at 300±50RPM in a heated state such that the temperature of the filler body is 130±5°C.

In the spray coating process, 20 to 40 wt% of the coating solution is sprayed onto the filler body 60 to 80 wt%, and the coating solution is based on the total weight of the filler body and the coating solution, 10 to 20 wt% diluent, and 9 to 12 wt% ph control agent. , And 1 to 2wt% of the coating agent.

According to an embodiment of the present invention, when a coating layer coated on the surface of a hollow filler is formed by using a coating agent having a double bond structure at the end of the chemical structure, the matrix resin forming the SMC and the coating agent when mixed in the SMC is chemically The bonding force between the hollow filler and the matrix resin can be improved while bonding.

Accordingly, it is possible to expect an effect capable of manufacturing SMC having low specific gravity and high strength.

1 to 3 is a chemical formula of a coating agent forming a coating layer of a hollow filler for SMC according to an embodiment of the present invention,
4 is a view showing the bonding relationship between the filler body and the coating layer of the hollow filler for SMC according to an embodiment of the present invention,
5 is a view showing a bonding relationship between the SMC hollow filler and the matrix resin of the SMC according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those skilled in the art is completely It is provided to inform you.

Hollow filler according to an embodiment of the present invention is a hollow filler mixed in the SMC formed by impregnating a matrix resin having a double bond structure to the reinforcing fiber, a filler body having a hollow formed therein; It consists of a coating layer formed by coating on the surface of the filler body. At this time, the coating layer is characterized in that it is chemically bonded to the matrix resin forming the SMC.

The filler body is an element provided to give the effect of lowering the weight of SMC by being mixed with the matrix resin of SMC, and is made of at least one of soda lime glass and borosilicate glass. Of course, the filler body is not limited to being made of the materials suggested above, and various materials that can be mixed with the matrix resin of SMC to lower the weight of SMC can be applied.

For example, the filler body may be molded into a hollow shape using soda lime glass. At this time, the diameter of the filler body is manufactured to about 20 ~ 50㎛, the density can be produced in 0.2 ~ 0.5g / cc.

The coating agent is an element that is coated on the outer surface of the filler body mixed with the matrix resin during the production of low specific gravity SMC and participates in the curing reaction during curing of the matrix resin. It is preferable that a coating agent having a double bond structure is applied to the end of the chemical structure so as to be able to bond.

For example, at least one of 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane and Trimethoxy(4-vinylphenyl)silane may be used as the coating agent.

At this time, the chemical formula of 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane is represented by [Chemical Formula 1], and [Chemical Formula 1] is illustrated in FIG. 1.

And, the chemical formula of 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane is represented by [Chemical Formula 2], and [Chemical Formula 2] is shown in FIG. 2.

And, the chemical formula of Trimethoxy(4-vinylphenyl)silane is represented by [Chemical Formula 3], and [Chemical Formula 3] is shown in FIG. 3.

On the other hand, Figure 4 is a view showing the bonding relationship between the filler body and the coating layer of the hollow filler for SMC according to an embodiment of the present invention, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane represented by [Formula 2] as a coating agent This figure shows the bonding relationship between the filler body and the coating layer in the filler used.

As can be seen in Figure 4, it can be seen that a functional group for a double bond structure is present in the coating agent forming the coating layer.

And, Figure 5 is a view showing a bonding relationship between the SMC hollow filler and the matrix resin of the SMC according to an embodiment of the present invention.

As can be seen in Figure 5, it can be confirmed that the coating agent forming the coating layer of the filler and the matrix resin of SMC are chemically bonded.

A method for manufacturing the hollow filler formed as described above will be described.

The method of manufacturing a hollow filler according to an embodiment of the present invention is a method of manufacturing a hollow filler mixed in SMC formed by impregnating a matrix resin having a double bond structure in a reinforcing fiber, and a filler body having a hollow formed therein A filler body preparation step of preparing; A coating liquid preparation step of preparing a coating liquid having a double bond structure at the terminal so that it can be chemically combined with the matrix resin; And a coating step of coating the prepared coating solution on the surface of the filler body.

1. Filler body preparation step

The filler body preparation step is a step of preparing a filler body that determines the overall shape and specific gravity of the hollow filler, and the inside is hollow using at least one of soda lime glass and borosilicate glass. Molded filler body.

As the filler body, a general filler used for low specific gravity SMC, which is used to reduce the specific gravity of SMC, can be used. In addition, the method of molding the filler body is not limited to a specific method, and various molding methods capable of realizing a hollow hollow shape may be used.

For example, the filler body may be manufactured to have a diameter of about 20 to 50 μm and a density of about 0.2 to 0.5 g/cc.

2. Coating solution preparation step

The coating solution preparation step is a step of preparing a coating solution having a double bond structure at the terminal so that it can be chemically combined with the matrix resin forming the SMC.

The coating solution preparation step includes a diluent preparation process for more specifically adjusting the pH of the diluent; It consists of a hydrolysis process in which a coating agent is added to a pH-adjusted diluent and hydrolyzed to prepare a coating solution.

The diluent preparation process is a process of preparing a diluent in which the coating agent is diluted, and a diluent of alcohols such as ethanol and methanol is used, and a pH adjusting agent such as acetic acid and ammonia water is used to adjust the pH. Therefore, a predetermined amount of a pH adjusting agent is mixed with a diluent and stirred to prepare a diluent adjusted to a desired level of pH.

At this time, the pH of the diluent is preferably set according to the type and amount of the coating agent added to the coating solution.

The hydrolysis process is a process of adding a coating agent to a pH-adjusted diluent and hydrolyzing it by stirring. In this case, it is preferable that a coating agent having a double bond structure at the terminal is applied as a coating agent.

For example, 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane and Trimethoxy(4-) represented by [Chemical Formula 1] to [Chemical Formula 3] in FIGS. At least one of vinylphenyl)silane is used.

At this time, the diluent to which the coating agent is added is heated to about 50° C. and stirred for about 30 minutes so that the hydrolysis reaction is performed smoothly.

On the other hand, the coating solution is preferably mixed with 10 to 20 wt% of the diluent, 9 to 12 wt% of the ph control agent, and 1 to 2 wt% of the coating agent, based on the total weight of the filler body and the coating solution.

3. Coating step

The coating step is a step of coating the prepared coating solution on the surface of the filler body.

The coating step is more specifically, a stirring process of putting the prepared filler body into a stirrer and stirring while applying heat; A spray coating process of coating the coating solution on the surface of the filler body by spraying the prepared coating solution while stirring the heated filler body; It consists of a diluent removal process to remove the diluent of the coating solution by heat-treating the filler body coated with the coating solution on the surface.

The stirring process is a process of preparing the coating to be smooth by applying heat while stirring the filler body. Therefore, the filler body is introduced into the stirrer and heat is provided inside the stirrer. At this time, the filler body is heated until the temperature of the filler body becomes 130±5°C.

The spray coating process is a process of coating a coating solution on the surface of the filler body by a spray coating method, and sprays the coating solution on the filler body heated to a desired temperature. At this time, the coating solution is sprayed while the filler body is stirred at 300±50RPM for uniform coating. That is why the coating layer is formed on the outer peripheral surface of the filler body.

On the other hand, it is preferable to coat by spraying 20 to 40 wt% of the coating solution in which the coating agent is mixed in the filler body 60 to 80 wt%. Thus, the amount of the coating agent contained in the coating solution is coated on the outer surface of the filler body.

The diluent removal process is a process of removing the diluent from the coating layer coated on the outer circumferential surface of the filler body. The filler body having the coating layer is introduced into a vacuum oven and dried at 130° C. for about 24 hours to remove the diluent remaining in the coating layer.

Next, the present invention will be described through comparative examples and examples.

The amount of the coating agent, the temperature and the stirring speed at the time of spray coating were changed to the conditions shown in Table 1 below to form a coating layer on the hollow filler, and this was mixed with the same amount of SMC in the same conditions to produce SMC. The tensile strength and coefficient of variation of the SMC thus prepared were measured, and the viscosity of a compound in which a hollow filler was mixed with a resin was measured for SMC production, and the values are shown in Table 1 below.

division Coating ratio Coating condition SMC evaluation Coating
[wt%] Filler body
[wt%] Temperature
[℃] speed
[RPM] Compound viscosity
[Poise] The tensile strength
[MPa] Coefficient of variation
[%] Example 1 One 70 130 300 120 78 8 Example 2 1.5 70 130 300 130 80 9 Example 3 2 70 130 300 140 83 10 Comparative Example 1 0.5 70 130 300 80 60 20 Comparative Example 2 2.5 70 130 300 250 65 20 Example 4 One 70 110 300 125 77 8 Example 5 One 70 140 300 123 76 9 Comparative Example 3 One 70 100 300 120 78 23 Comparative Example 4 One 70 150 300 120 78 25 Example 6 One 70 130 250 124 77 9 Example 7 One 70 130 350 121 79 7 Comparative Example 5 One 70 130 200 160 64 27 Comparative Example 6 One 70 130 400 120 78 25

As can be seen in Table 1, Example 1 to Example 6, the amount of the coating agent, the coating temperature and the stirring speed satisfies the conditions presented in the present invention, the viscosity of the compound maintains 120 ~ 140 poise coating is made smoothly The coefficient of variation was maintained at 10% or less, and accordingly, it was confirmed that the tensile strength of SMC was maintained excellently at 78 Mpa or more.

On the other hand, Comparative Example 1 is a comparative example in which the amount of the coating agent is less than the suggested conditions, it was confirmed that the SMC tensile strength is lower than the example and the coefficient of variation is high. It can be inferred that this is because the amount of the coating agent is too small to achieve sufficient chemical bonding between the matrix resin of the SMC and the coating layer, so that the filler body and the matrix resin are not formed at a desired level.

Comparative Example 2 is a comparative example in which the amount of the coating agent is more than the suggested conditions, it was confirmed that the SMC tensile strength is lower than the example and the coefficient of variation is high. In particular, it was confirmed that the viscosity of the compound was significantly higher than the example. It can be inferred that the amount of the coating agent is too large and the viscosity of the compound increases, so that the coating agent is not sufficiently coated on the filler body, and thus the chemical bond between the matrix resin of the SMC and the coating layer is not sufficiently achieved. It can be inferred that the resin bond was not formed at a desired level.

Comparative Examples 3 to 6 are comparative examples in which the temperature and agitation rate at the time of coating are lower or higher than the suggested conditions, and it can be confirmed that the variation coefficients of Comparative Examples 3 to 6 are significantly higher than those of the examples. It can be inferred that the temperature and agitation rate conditions during coating have a large influence on the coefficient of variation.

Although the present invention has been described with reference to the accompanying drawings and preferred embodiments described above, the present invention is not limited thereto, and is limited by the claims below. Therefore, one of ordinary skill in the art can variously modify and modify the present invention without departing from the technical spirit of the claims to be described later.

Claims (12)

As a hollow filler mixed in the SMC formed by impregnating the matrix resin having a double bond structure to the reinforcing fiber,
A filler body having a hollow formed therein;
Hollow filler for SMC characterized in that it is formed of a coating layer formed of a coating agent having a double bond structure at the end so as to be chemically bonded to the matrix resin, which is formed on the surface of the filler body.
The method according to claim 1,
The filler body is a hollow filler for SMC, characterized in that at least one of soda lime glass (soda lime glass) and borosilicate glass (borosilicate glass).
The method according to claim 1,
The coating agent is a hollow filler for SMC, characterized in that at least one of 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane and Trimethoxy(4-vinylphenyl)silane.
The method according to claim 3,
The coating agent is a hollow filler for SMC, characterized in that at least one of the low-molecular materials represented by the following [Formula 1] to [Formula 3].
[Formula 1]

[Formula 2]

[Formula 3]

As a method for manufacturing a hollow filler mixed in the SMC formed by impregnating the matrix resin having a double bond structure to the reinforcing fiber,
A filler body preparation step of preparing a filler body with a hollow formed therein;
A coating liquid preparation step of preparing a coating liquid having a double bond structure at the terminal so that it can be chemically combined with the matrix resin;
Method for manufacturing a hollow filler for SMC comprising a coating step of coating the prepared coating solution on the surface of the filler body.
The method according to claim 5,
The filler body preparation step,
A method of manufacturing a hollow filler for SMC, characterized in that the inside of the filler body is molded using at least one of soda lime glass and borosilicate glass.
The method according to claim 5,
The coating liquid preparation step,
A diluent preparation process for adjusting the pH of the diluent;
Method of manufacturing a hollow filler for SMC, characterized in that consisting of a hydrolysis process to prepare a coating solution by adding a coating agent to the pH-adjusted diluent and hydrolyzing.
The method according to claim 7,
In the process of preparing the diluent, a diluent of alcohol is used, and a method of manufacturing a hollow filler for SMC is characterized in that a pH adjusting agent is mixed with the diluent for pH adjustment.
The method according to claim 7,
The coating agent used in the hydrolysis process is characterized in that the coating agent is at least one of 2-(2,4-Divinyl)cyclohexylethyltrimethoxysilane, 2-(2,4-Divinyl)cyclohexylethyltriethoxysilane and Trimethoxy(4-vinylphenyl)silane. Manufacturing method of hollow filler for SMC.
The method according to claim 5,
The coating step,
A stirring process of putting the prepared filler body into a stirrer and stirring while applying heat;
A spray coating process of coating the coating solution on the surface of the filler body by spraying the prepared coating solution while stirring the heated filler body;
Method for manufacturing a hollow filler for SMC, characterized in that it consists of a diluent removal process to remove the diluent of the coating solution by heat-treating the filler body coated with the coating solution on the surface.
The method according to claim 10,
The spray coating process is a method of manufacturing a hollow filler for SMC, characterized in that carried out while stirring at 300±50 RPM while the temperature of the filler body is 130±5° C. heated.
The method according to claim 11,
In the spray coating process, the filler body is coated by spraying 20 to 40 wt% of the coating solution on 60 to 80 wt%,
The coating solution is based on the total weight of the filler body and the coating solution, a method of manufacturing a hollow filler for SMC, characterized in that mixed with 10 ~ 20wt% of diluent, 9 ~ 12wt% of ph regulator, and 1 ~ 2wt% of coating agent.

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