KR102345950B1 - Elastic polymer structure and preparation method thereof - Google Patents

Abstract

According to the present invention, a high-quality elastic polymer structure can be efficiently provided by pressure-heat post treatment of applying a specific pressure and temperature to a three-dimensionally printed thermoplastic resin output. In addition, an elastic polymer structure prepared by a method according to one embodiment of the present invention has excellent mechanical properties and elasticity due to low porosity and surface roughness, and can also have a smooth leather-like surface texture.

Description

Elastic polymer structure and method for manufacturing the same

The present invention relates to a polymer elastic structure having a specific range of porosity and surface roughness, and a method for manufacturing the same.

With the spread of 3D (3D) printers, 3D printing (output) products have appeared in various fields. In order to produce such a product, various printing methods have been introduced, and research for improving the quality of the printed product is being actively conducted.

In particular, according to a 3D printing method using a polymer material, an output with excellent elasticity can be freely formed into a desired shape, and a 3D printing method using a polymer material is being studied in various fields.

In this regard, for example, Korean Patent Registration No. 19983994 discloses a method of manufacturing a skin material for an automobile interior including a 3D image realization layer using a thermoplastic polyurethane (TPU, Thermoplastic Polyurethane).

However, in the case of the output (skin material) manufactured by the above method, moisture penetrates between the pores of the TPU output, so that the structure of the output is easily deformed, and the texture and quality are deteriorated due to high surface roughness.

Accordingly, methods such as applying additional paint or attaching a film on the output have been studied to improve the surface properties, but even in this case, there is a possibility that quality problems such as pushing and peeling of dissimilar materials may be caused, and additional There is a problem in that process costs occur.

Republic of Korea Patent No. 19983994

The present invention has been devised to solve the above conventional problems, and the first technical problem to be solved by the present invention is to have a specific range of porosity and surface roughness, so that the shape is not easily deformed due to the penetration of moisture and the texture is improved It is to provide a high-quality polymer elastic structure having a.

In addition, a second technical problem to be solved by the present invention is to provide a method for manufacturing an elastic polymer structure capable of controlling the surface porosity and surface roughness of the elastic polymer structure to a desired range.

In addition, a third technical problem to be solved by the present invention is to provide a high-quality vehicle seat including the elastic polymer structure.

In order to achieve the above object, one embodiment provides a polymer elastic structure comprising a thermoplastic resin and having a porosity of 0.06 to 0.16 and a surface roughness of 400 or less as measured by a scanning electron microscope (SEM).

Another embodiment, 1) using a thermoplastic resin powder, the selective laser sintering (SLS, Selective Laser Sintering) method to three-dimensional (3D) outputting a molding of a desired shape; and 2) post-processing the thermoplastic resin output at a pressure of 3N to 7N and a temperature of 130°C to 160°C.

Another embodiment provides a vehicle seat comprising the elastic polymer structure.

According to the embodiment of the present invention, a high-quality elastic polymer structure having low porosity and surface roughness can be efficiently provided by applying a specific pressure and temperature to the 3D-printed thermoplastic resin output and performing thermal pressure post-treatment.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.
1 is a schematic process flow diagram of a method for manufacturing an elastic polymer structure according to an embodiment of the present invention.
Figure 2 shows the scanning electron microscope (SEM, Scanning Electron Microscope) measurement results of the leather (skin) of Comparative Example 1, and Comparative Examples 2 and 6 of the elastic structure.
3 is an image and graph showing a surface roughness measurement and analysis method using a principal component analysis (PCA) of the elastic structure according to the embodiment.
4 is a graph showing the measurement result of the surface roughness (surface roughness) of the elastic structures of Comparative Example 2 and Examples 1, 3, 5, and 6;

In the present specification, "including" any component means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in the present specification are modified by the term "about" in all cases unless otherwise specified.

In the present specification, unless otherwise specified, the expression "a" and "a" should be construed as meaning including the singular or the plural as interpreted in context.

Hereinafter, the present invention will be described in detail.

The elastic polymer structure according to an embodiment of the present invention includes a thermoplastic resin, and has a porosity of 0.06 to 0.16 and a surface roughness of 400 or less as measured by a scanning electron microscope (SEM).

According to an embodiment of the present invention, since the elastic polymer structure has a porosity within a specific range, moisture can penetrate into the elastic structure to minimize deformation of the shape of the structure, and by having a surface roughness in a specific range, the elastic structure of the elastic structure The surface texture can be improved.

Hereinafter, a polymer elastic structure according to an embodiment of the present invention will be described in detail.

polymer elastic structure

The elastic polymer structure according to an embodiment of the present invention includes a thermoplastic resin.

The thermoplastic resin is at least one selected from the group consisting of thermoplastic polyurethane (TPU), acrylonitrile-butadiene-styrene copolymer (ABS, acrylonitrile-butadiene-styrene copolymer) and polyamide (PA, polyamide) may include Specifically, the thermoplastic resin may include TPU.

The TPU has a soft segment and a hard segment formed through block copolymerization, and an elastic structure of various hardness can be formed according to their ratio. That is, the elastic structure made of TPU may have the most excellent mechanical properties such as tensile strength, tear strength, and abrasion resistance due to the strong urethane interaction between the polymer main chains.

Specifically, the TPU is a copolymer in which a soft portion having a glass transition temperature (Tg) lower than 0° C. and a hard portion higher than 0° C. are continuously connected. The soft part in the TPU is a linear polymer chain such as polyester or polyether, and the hard part may be composed of a hard compound such as a urethane group or a urea group.

The glass transition temperature (Tg) of the thermoplastic resin may be 50 °C to 200 °C, for example, 70 °C to 160 °C, for example, 70 °C to 130 °C, for example, 70 °C to 120 °C.

The melting point of the thermoplastic resin may be 170 °C to 300 °C, for example, 170 °C to 250 °C, for example, 170 °C to 230 °C.

The thermoplastic resin having a melting point in the above range may be applied to a selective laser sintering (SLS) method to output a desired shape. If a thermoplastic resin having a melting point of less than 170° C. is used, the thermoplastic resin may be easily melted during sintering by the SLS method, resulting in defects in the thermoplastic resin output. In addition, when a thermoplastic resin having a melting point exceeding 300° C. is used, the thermoplastic resin that has not been sintered by the SLS method remains, and thus the roughness of the thermoplastic resin output may be further increased.

The weight average molecular weight (Mw) of the thermoplastic resin may be 30,000 to 150,000 g/mol, for example, 40,000 to 120,000 g/mol, for example, 50,000 to 100,000 g/mol.

In addition, the polydispersity index (PDI, Mw/Mn) of the thermoplastic resin may be greater than 1 to 2.7, for example, 1.5 to 2.6, for example, 1.7 to 2.5. In this case, Mn is a number average molecular weight, and the PDI is calculated by dividing the measured weight average molecular weight by the number average molecular weight. Both the weight average molecular weight and the number average molecular weight may be measured by gel permeation chromatography (GPC).

When the weight average molecular weight and polydispersity index of the thermoplastic resin satisfy the above ranges, mechanical properties such as elasticity, flexibility and tensile strength, tear strength, and abrasion resistance of the thermoplastic resin may be further improved.

On the other hand, the elastic polymer structure according to an embodiment of the present invention has a porosity of 0.06 to 0.16. Specifically, the porosity of the elastic polymer structure may be, for example, 0.06 to 0.15, for example, 0.06 to 0.148, for example, 0.06 to 0.147, for example, 0.08 to 0.147.

The elastic polymer structure satisfying the porosity of the above range is not easily deformed because the penetration of moisture between the pores of the elastic structure is suppressed.

Specifically, the smaller the porosity of the elastic polymer structure, the smaller the pores can be to prevent the penetration of moisture into the pores. If the porosity of the elastic polymer structure exceeds 0.16, the shape of the structure is deformed due to moisture penetration between the pores of the elastic structure, and defects may occur or quality may be deteriorated.

The porosity of the elastic polymer structure may be calculated by photographing the surface of the elastic polymer structure using a scanning electron microscope (SEM). For example, after image normalization for pore extraction of the surface of the elastic structure, an experimental threshold value (below -1) is selected, and quantified as a ratio of voids to the image can be obtained.

Meanwhile, the surface roughness of the elastic polymer structure may be 400 or less. Specifically, the surface roughness of the elastic polymer structure may be, for example, 350 or less, for example, 300 or less, for example, 250 or less, for example, 200 or less.

The closer to 0 the surface roughness of the elastic polymer structure means, the flatter the surface. The elastic polymer structure satisfying the surface roughness of the above range may have an improved surface texture due to a smooth and flat surface, and furthermore may implement a leather texture. If, when the surface roughness of the elastic polymer structure exceeds 400, the quality of the elastic polymer structure is deteriorated, there may be a limit in terms of utilization.

The surface roughness of the elastic polymer structure may be measured using SEM. For example, with reference to Fig. 3 (a) to (c), after photographing the side surface of the elastic polymer structure by SEM, extracting the edge (Fig. 3 (a) and (b)), quantifying the surface roughness For this purpose, the principal component was extracted using PCA (Principal Component Analysis), and the dispersion of the vertical distance between the principal component axis and the corner point was defined as the roughness (Fig. 3(c)).

The elastic polymer structure according to the embodiment of the present invention has a specific range of porosity and surface roughness, thereby preventing moisture from penetrating into the elastic polymer structure and deforming the structure, and may have an improved texture. In particular, the elastic polymer structure can be utilized in various fields because it can realize a leather texture by satisfying the porosity and surface roughness ranges.

The porosity and surface roughness of the elastic polymer structure can be controlled by post-processing an output obtained by 3D printing using a thermoplastic resin powder at a specific pressure and temperature.

Hereinafter, a method for manufacturing an elastic polymeric structure according to an embodiment of the present invention will be described in detail.

Method for manufacturing elastic polymer structure

The manufacturing method of the elastic polymer structure according to an embodiment of the present invention comprises the steps of: 1) three-dimensionally (3D) outputting a molded product of a desired shape by a selective laser sintering (SLS) method using a thermoplastic resin powder; and 2) post-processing the thermoplastic resin output at a pressure of 3N to 7N and a temperature of 130°C to 160°C.

Referring to FIG. 1, in the method for manufacturing an elastic polymer structure according to an embodiment of the present invention (S100), 3D output is performed by the SLS method using a thermoplastic resin powder (S110), and the thermoplastic resin output is subjected to a specific pressure and temperature. It is characterized in that it is added and post-processed (S120), whereby a high-quality elastic polymeric structure having low porosity and surface roughness can be efficiently provided.

Hereinafter, each process is described in detail step by step:

(1) 3D output by SLS method (S110)

In the method for manufacturing an elastic polymer structure according to an embodiment of the present invention, the step (1) is a step of three-dimensionally (3D) outputting a molded product of a desired shape by the SLS method using a thermoplastic resin powder.

The type and physical properties of the thermoplastic resin are the same as described above.

In addition, the thermoplastic resin is used in the form of a powder, because the SLS method is a powder-based output method.

The SLS method is a method of material processing using a laser, and is a method of selectively solidifying a material such as powder by using a selective energy transfer function of a laser.

The 3D output of the thermoplastic resin by the SLS method has better elasticity and no breakage compared to the 3D output of the thermoplastic resin by the melt extrusion modeling (FDM, Fused Deposition Modeling) and photo-curable resin lamination (SLA, Stereo Lithography Apparatus) method. Excellent quality can be realized.

The 3D output using the SLS method may use, for example, a Vanguard system available from 3D Systems, Inc.

Specifically, in step (1), the thermoplastic resin powder is thinly placed on the bed, and then the process of melting and hardening the part selected by the laser in the SLS method is repeated to 3D output a molded product of a desired shape.

The 3D printed output using the SLS method has excellent elasticity, flexibility, and mechanical properties.

(2) post-processing the output (S120)

In the method for manufacturing an elastic polymer structure according to an embodiment of the present invention, the step (2) is a step of post-processing the thermoplastic resin output at a pressure of 3N to 7N and a temperature of 130°C to 160°C.

According to the embodiment of the present invention, it is possible to significantly reduce the porosity and surface roughness of the elastic polymer structure by post-processing the thermoplastic resin output obtained in step (1) by applying the specific pressure and temperature. It is possible to minimize the deformation of the shape and improve the surface texture.

If the thermoplastic resin output is not post-processed, the thermoplastic resin that has not been sintered by the SLS method remains on the surface of the output, which may increase surface roughness.

In the post-treatment, pressure and temperature conditions may be very important factors in controlling the porosity and surface roughness of the elastic polymer structure.

The pressure may be 3N to 7N, for example 3N to 6N, for example 3N to 5N, for example 3N to 4N, for example 4N to 5N. If the pressure is less than 3N, the porosity and surface roughness of the elastic structure may increase, and if it exceeds 7N, there may be a problem of shape deformation of the elastic structure.

The temperature may be 130 °C to 160 °C, for example 140 °C to 160 °C, for example 140 °C to 155 °C, for example 140 °C to 150 °C, for example 140 °C to 145 °C.

The temperature is a very important factor in order to realize the desired effect in the present invention, and the physical properties of the elastic structure may be sensitively changed according to the temperature.

In the post-treatment method, by post-treatment within a specific temperature range below the melting point of the thermoplastic resin, the surface of the elastic polymer structure is made smooth and flat, and the interior of the structure maintains the inherent elasticity and mechanical properties of the thermoplastic resin and the structure can be stably maintained without deformation.

If the temperature is less than 130 ℃, the effect of reducing the porosity and surface roughness of the elastic polymer structure may be insignificant, and if the temperature exceeds 160 ℃, the thermoplastic resin melts and the structure of the elastic structure may be deformed.

Meanwhile, the porosity and surface roughness of the elastic polymer structure may vary depending on the post-treatment time.

The post-treatment time may be 20 minutes to 80 minutes, for example 20 minutes to 70 minutes, for example 30 minutes to 70 minutes, for example 30 minutes to 60 minutes, for example 40 minutes to 60 minutes.

When the post-treatment time satisfies the above range, it is possible to reduce the porosity and surface roughness of the elastic polymer structure, and in particular, it is more advantageous to provide an elastic structure having a smooth leather texture by significantly reducing the surface roughness. can

If the post-treatment time is less than 20 minutes, the effect of reducing the porosity and surface roughness of the elastic polymer structure may be insignificant, and when the post-treatment time exceeds 80 minutes, the shape of the elastic structure is greatly deformed depending on the pressure direction can be

In addition, the post-treatment time may vary depending on the temperature and pressure. For example, when the temperature is 140 °C to 150 °C and the pressure is 3N to 5N, the post-treatment time may be suitable for 30 minutes to 60 minutes. Specifically, when the temperature is 140 °C to 150 °C and the pressure is 3N, the post-treatment time may be 40 minutes to 60 minutes. In this case, it is possible to effectively control the porosity and surface roughness of the elastic polymer structure.

In the method for manufacturing an elastic polymer structure according to an embodiment of the present invention, a molded product of a desired shape is 3D output by the SLS method using a thermoplastic resin, and the output is post-processed by applying a specific pressure and temperature, so that the porosity of the elastic structure is It is possible to minimize the deformation of the shape of the structure due to penetration of moisture in the elastic polymer structure by reducing the , and it is possible to further improve the surface texture by reducing the surface roughness of the elastic structure.

In particular, by combining the SLS method and the post-treatment method under specific conditions, a high-quality elastic polymer structure can be easily and efficiently manufactured. That is, by using the SLS method, it is possible to further improve the elasticity of the 3D printed product and minimize breakage, and it is possible to improve the structural stability and texture of the elastic polymer structure by using a post-processing method under specific conditions. In addition, due to the use of a thermoplastic resin, especially TPU, it may have mechanical properties such as excellent elasticity, flexibility, tensile strength, tear strength, and abrasion resistance.

Accordingly, the elastic polymer structure can be applied to various fields.

Embodiments of the present invention may provide a vehicle seat including the elastic polymer structure.

That is, the vehicle seat including the elastic polymer structure may have a texture similar to leather. Accordingly, even if natural leather is not used, it is possible to provide a leather-like texture, which can be very effective in terms of cost.

The vehicle seat according to the embodiment of the present invention may be an integrated seat in which an inner foam and an outer skin are integrated.

In addition, the elastic polymer structure manufactured through the post-processing process of the 3D thermoplastic resin output has a strong, smooth and excellent leather-like surface texture, so it can be utilized in various fields, especially for realizing high-quality vehicle seats. can be more usefully applied to

[Example]

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to these examples.

<Production of elastic polymer structure>

Example 1

Thermoplastic polyurethane (TPU, Sinterit's Flexa black) powder was 3D printed by selective laser sintering (SLS, Sinterit's Lisa) to obtain a TPU output of 20 X 20 X 10 (mm).

The TPU output was put into a preheated oven at 140° C. with a pressure of 3N applied using a weight of 0.3 kg, and post-processed at 140° C. for 30 minutes to obtain a TPU elastic structure.

At this time, in order to prevent the surface of the TPU output from melting and sticking to the weight, a Teflon material board was disposed between the weight and the TPU output.

Examples 2 to 6

A TPU elastic structure was obtained in the same manner as in Example 1, except that the post-treatment was performed by changing the pressure and temperature, and the post-treatment time as described in Table 1 below.

Comparative Example 1

Leather obtained from SNB was used.

Comparative Example 2

After obtaining the TPU output, a TPU elastic structure was obtained in the same manner as in Example 1, except that post-treatment was not performed.

In the case of Examples 1 to 6 and Comparative Example 2, four samples of the TPU elastic structure were prepared and used, respectively, and one sample was used for the leather of Comparative Example 1.

The post-treatment conditions of Examples and Comparative Examples are summarized in Table 1 below:

test example

Test Example 1: SEM measurement of leather and elastic polymer structures

By taking a scanning electron microscope (SEM, Scanning Electron Microscope) at the same magnification (x 100) for the surface of the leather (skin) of Comparative Example 1, and the TPU elastic structure of Comparative Example 2 and Example 6, each surface image was obtained 2 is shown.

As can be seen in Figure 2, the TPU elastic structure without the post-treatment of Comparative Example 2 had significantly higher porosity (voids) than the leather of Comparative Example 1, and the surface of the elastic structure was very rough.

In contrast, the post-treatment TPU elastic structure of Example 6 had significantly lower porosity and surface roughness compared to the TPU elastic structure of Comparative Example 2.

Test Example 2: Measurement of porosity

The leather (skin) of Comparative Example 1, and the surface of the TPU elastic structures of Comparative Examples 2 and 1 to 6 were SEM photographed three times at the same magnification (x 100), respectively, to calculate the average porosity.

After image normalization for void extraction of the surface of the elastic structure, an experimental threshold value (less than -1) was selected, and then quantified as an image-to-void ratio.

At this time, the porosity of the elastic structure was calculated using the following formula:

[Equation 1]

Porosity = pore area in SEM image/total area in SEM image

The measurement results of the average porosity of the leather of Comparative Example 1 and the TPU elastic structures of Comparative Examples 2 and 6 are shown in Table 2 below.

As can be seen in Table 2, the TPU elastic structures of Examples 1 to 6 confirmed that the average porosity was reduced to 0.06 to 0.16 by post-processing the 3D TPU output by the SLS method.

Specifically, it was confirmed that the average porosity of the TPU elastic structures of Examples 1 to 6 varied with post-treatment temperature, pressure, and time. In particular, the average porosity of the TPU elastic structure of Example 4 post-treated at a temperature of 150 ° C. and a pressure of 3N for 60 minutes was 0.0913, which was close to the average porosity value (0.0558) of the leather of Comparative Example 1.

In contrast, in the case of the TPU elastic structure of Comparative Example 2 without post-processing the output obtained after 3D printing, the average porosity was 0.1654, which significantly increased than the average porosity of the TPU elastic structures of Examples 1 to 6 have.

Test Example 3: Measurement of surface roughness

Referring to (a) and (b) of Figure 3, the edges of the leather of Comparative Example 1 and the side surfaces of the TPU elastic structures of Comparative Examples 2 and 1 to 6 were taken three times by SEM and then the edges were extracted.

Then, with reference to FIG. 3(c), to quantify the surface roughness, the principal component is extracted using PCA, and the vertical distance dispersion between the extracted principal component axis and the corner point is calculated. It was defined as roughness.

The results of the surface roughness of the TPU elastic structures of Comparative Examples and Examples measured in this way are shown in FIG. 4 . At this time, as the surface of the TPU elastic structure is flatter, the vertical distance dispersion is close to zero.

As can be seen in Figure 4, the TPU elastic structures of Examples 1, 3, 5 and 6 confirmed that the surface roughness of the structure was reduced to 200 or less by post-processing the 3D TPU output by the SLS method.

Specifically, the surface roughness of the TPU elastic structures of Examples 1, 3, 5 and 6 are all 200 or less, and in particular, the surface roughness of the TPU elastic structures of Examples 3, 5 and 6 is 100 or less, and the surface roughness exceeds 400 It was confirmed that the surface roughness was significantly reduced compared to the TPU elastic structure of Comparative Example 2.

On the other hand, it was confirmed that the surface roughness of the TPU elastic structure depends on the post-treatment temperature, pressure, and time, and in particular, it was confirmed that the effect of the post-treatment time is the greatest.

For example, comparing Examples 3, 5, and 6 post-treatment at 140 ° C., the surface roughness of the TPU elastic structure was as low as 200 or less, but in particular, the post-treatment was performed for 60 minutes like the TPU elastic structure of Example 3 When carried out during the period, the surface roughness even at a low pressure of 3N was lower than that of the TPU elastic structures of Examples 5 and 6. Even if the pressure is increased to 5N at the same temperature as in Example 3 as in Example 5, when the post-treatment time is shorter than 30 minutes, it can be seen that the surface roughness of the TPU elastic structure is slightly increased.

Claims (8)

It contains a thermoplastic polyurethane (TPU, thermoplastic polyurethane) having a melting point of 170 ℃ to 250 ℃,
A polymer elastic structure having a porosity of 0.06 to 0.16 and a surface roughness of 400 or less as measured by a scanning electron microscope (SEM).
delete 1) Using a thermoplastic polyurethane (TPU) powder having a melting point of 170 ° C to 250 ° C, a three-dimensional (3D) output of a molding of a desired shape by a selective laser sintering (SLS) method step; and
2) post-processing the output obtained in step 1) at a pressure of 3N to 7N and a temperature of 130°C to 160°C;
A method of manufacturing the elastic polymer structure of claim 1, comprising a.
delete 4. The method of claim 3,
Performing the post-treatment of step (2) for 20 to 80 minutes, a method for producing an elastic polymer structure.
6. The method of claim 5,
The post-treatment of step (2) is performed at a pressure of 3N to 5N and a temperature of 140 °C to 150 °C for 30 minutes to 60 minutes, a method for producing an elastic polymer structure.
A vehicle seat comprising the elastic polymer structure of claim 1 .
8. The method of claim 7,
The vehicle seat is an integral seat in which an inner foam and an outer skin are integrated.

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