Back panel fastening bracket and its manufacturing method

Abstract

The present invention relates to a back panel fastening bracket for assembling a back panel to a furniture body, wherein the back panel fastening bracket for assembling a back panel to a furniture body comprises: a fastening portion into which a fastening screw is inserted; and a wing extending from the upper portion of the fastening portion and inserted into the back panel groove of the furniture body into which the back panel is inserted; wherein the fastening portion comprises a first fastening portion having a first fastening groove formed in a part of the upper portion from which the inserted fastening screw exits, and a second fastening portion protruding from one side of the first fastening portion and having a second fastening groove formed into which the fastening screw is inserted.

Description

Technology Field

[0001] The present invention relates to a back plate fastening bracket and a method for manufacturing the same. Background Technology

[0003] Generally, furniture consists of a top panel, bottom panel, side panels, and back panel, and the top panel, bottom panel, and side panels are assembled and joined as a single unit using fastening screws.

[0004] The back panel is placed behind the assembled and combined top, bottom, and side panels, and secured by driving in metal staples.

[0005] However, this method has problems where the fastening force varies depending on the operator's skill level, causing the back panel to easily detach or the books to push against the back panel and slide backward when storing books.

[0006] A prior art for solving this problem is Korean Registered Patent No. 10-1380979 (March 27, 2014).

[0007] However, conventional technology assembles the back panel by inserting it into guide grooves formed in the top, bottom, and side panels, which causes the entire furniture frame to warp when used for a long period after storing heavy objects.

[0008] In addition, there is a problem in that a gap remains in the guide groove where the back plate is inserted, causing the back plate to shake upon impact and potentially detach due to the shaking. The problem to be solved

[0010] The problem that the present invention aims to solve is to provide a back plate fastening bracket and a method for manufacturing the same, which prevents the back plate from detaching from the back plate groove by minimizing the gap of the back plate to prevent shaking.

[0011] Another problem that the present invention aims to solve is to provide a back panel fastening bracket and a method for manufacturing the same, which can prevent the furniture frame from warping even when used for a long period after storing heavy objects.

[0012] Another problem that the present invention aims to solve is to provide a back plate fastening bracket with high productivity and cost reduction, and a method for manufacturing the same.

[0013] Another problem that the present invention aims to solve is to provide a back plate fastening bracket with high mechanical properties that does not break easily, and a method for manufacturing the same. means of solving the problem

[0015] In order to solve the above technical problem, according to a preferred aspect of the present invention, a back panel fastening bracket for assembling a back panel to a furniture body comprises: a fastening portion into which a fastening screw is inserted; and a wing extending from the upper portion of the fastening portion and inserted into the back panel groove of the furniture body into which the back panel is inserted; wherein the fastening portion comprises a first fastening portion having a first fastening groove formed in a part of the upper portion through which the inserted fastening screw exits, and a second fastening portion protruding from one side of the first fastening portion and having a second fastening groove formed into which the fastening screw is inserted.

[0016] Here, the first fastening groove may be formed to extend to a part of the wing.

[0017] Additionally, it may further include a slimming groove formed on a part of at least one of the other side and upper portion of the first fastening portion to prevent shrinkage of the back plate fastening bracket.

[0018] Additionally, it may further include a wing support portion that is formed extending from the fastening portion at the lower part of the wing and supports the wing.

[0019] According to another preferred aspect of the present invention, a back panel fastening bracket for assembling a back panel to a furniture body can be provided, wherein the back panel fastening bracket is made of a polyamide-based composite material obtained by melt blending polyamide (polyamide 6, PA6), modified polypropylene (m-PP), and a compatibilizer.

[0020] Here, the modified polypropylene (m-PP) can be produced by adding a radical initiator and a multifunctional modifier to polypropylene (PP) and reactively extruding it.

[0021] Here, the polyfunctional modifier may be trimethylolpropane trimethacrylate (TMPTMA) and divinylbenzene (DVB).

[0022] Here, the compatibilizer may be at least one of maleic anhydride-grafted polypropylene (MA-g-PP) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS).

[0023] According to another preferred aspect of the present invention, a method for manufacturing a back plate fastening bracket comprises the steps of: producing modified polypropylene (m-PP) by reaction extrusion of polypropylene (PP) with a radical initiator and a multifunctional modifier; producing a polyamide-based composite material by melt blending a polyamide (polyamide 6, PA6), the modified polypropylene (m-PP), and a compatibilizer; and producing the back plate fastening bracket by injection molding the polyamide-based composite material. Effects of the invention

[0025] The present invention has the effect of preventing the back plate from detaching from the back plate groove by minimizing the gap of the back plate to prevent shaking.

[0026] In addition, the present invention has the effect of preventing the furniture frame from warping even when used for a long period after storing heavy objects.

[0027] In addition, the present invention has the effect of increasing productivity and reducing costs when manufacturing a back plate fastening bracket.

[0028] In addition, the present invention has the effect of preventing the back plate fastening bracket from being easily damaged due to its high mechanical properties. Brief explanation of the drawing

[0030] FIG. 1 is a perspective view of a back plate fastening bracket according to one embodiment of the present invention. FIG. 2 is a plan view of a back plate fastening bracket according to one embodiment of the present invention. FIG. 3 is a diagram showing the usage state of a back plate fastening bracket according to one embodiment of the present invention. Figure 4 is a graph showing the results of evaluating moldability according to the radical initiator content of modified polypropylene (m-PP) used to manufacture a back plate fastening bracket according to one embodiment of the present invention. Figure 5 is a graph showing the results of the evaluation of physical properties of m-PP according to the content of a multifunctional modifier in the modified polypropylene (m-PP) used to manufacture a back plate fastening bracket according to one embodiment of the present invention. Figure 6 is a graph showing the results of evaluating the physical properties of modified polypropylene (m-PP) according to the process screw speed of the modified polypropylene (m-PP) used in the production of a back plate fastening bracket according to one embodiment of the present invention. FIG. 7 is a graph showing the results of evaluating physical properties according to the content of polyamide (polyamide 6, PA6) and modified polypropylene (m-PP) of a polyamide-based composite material used to manufacture a back plate fastening bracket according to one embodiment of the present invention. FIGS. 8 and 9 are graphs showing the results of the physical property evaluation according to the type and content of the commercially available polyamide-based composite material used to manufacture a back plate fastening bracket according to one embodiment of the present invention. FIG. 10 is a flowchart of a method for manufacturing a back plate fastening bracket according to another embodiment of the present invention. Specific details for implementing the invention

[0031] The present invention is susceptible to various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but such components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0032] When it is stated that one component is 'connected' or 'connected' to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is 'directly connected' or 'directly connected' to another component, it should be understood that there are no other components in between.

[0033] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0034] FIG. 1 is a perspective view of a back plate fastening bracket according to one embodiment of the present invention.

[0035] FIG. 2 is a plan view of a back plate fastening bracket according to one embodiment of the present invention.

[0036] FIG. 3 is a diagram showing the usage state of a back panel fastening bracket according to one embodiment of the present invention. FIG. 3(a) is a diagram showing the usage state in which only the back panel (20) and the back panel fastening bracket (100) are assembled in the back panel groove (11) of the furniture body (10), and FIG. 3(b) is a diagram showing the usage state in which the back panel (20) and the back panel fastening bracket (100) are assembled in the back panel groove (11) of the furniture body (10) and fixed with a fastening screw (30).

[0037] Referring to FIGS. 1 to 3, the back plate fastening bracket (100) according to the present invention is used to assemble a back plate (20) to a furniture body (10). The back plate fastening bracket (100) is inserted and coupled together with the back plate (20) in the back plate groove (11) of the furniture body (10). Specifically, after the back plate (20) is inserted and coupled into the back plate groove (11) of the furniture body (10), the wing (120) of the back plate fastening bracket (100) is inserted into the empty space of the remaining back plate groove (11) to fill the empty space of the remaining back plate groove (11) when only the back plate (20) is inserted and coupled. This minimizes the gap of the back plate (20), preventing it from shaking and preventing the back plate (20) from coming off the back plate groove (11). This strengthens the fixation of the back plate (20) without conventional fasteners and prevents the furniture frame from warping overall when used for a long period after storing heavy objects.

[0038] Additionally, when the back panel fastening bracket (100) is inserted and coupled with the back panel (20) into the back panel groove (11) of the furniture body (10), a fastening screw (30) is inserted through the fastening part (110) so that the furniture body (10) and the back panel (20) are fixed.

[0039] The back plate fastening bracket (100) includes a fastening part (110), a wing (120), a slimming groove (130), and a wing support part (140).

[0040] The fastening part (110) allows a fastening screw (30) to be inserted into and then removed to secure the furniture body (10) and the back plate (20), and includes a first fastening part (111) and a second fastening part (112).

[0041] The first fastening part (111) is in the shape of a triangle, with the height portion in contact with the furniture body (10), and a first fastening groove (111-1) is formed in a part of the upper portion through which a fastening screw (30) inserted through the second fastening groove (112-1) comes out, and the interior is hollow so that the first fastening groove (111-1) and the second fastening groove (112-1) are connected, thereby accommodating a portion of the fastening screw (30) inserted through the second fastening groove (112-1) inside.

[0042] The first fastening groove (111-1) is formed to extend from the upper part of the first fastening part (111) to a part of the wing (120) so as to reduce the load when fastening by inserting the fastening screw (30) into the fastening part (110), and the fastening screw (30) is inserted into the inside of the furniture body (10) to increase the fastening force between the furniture body (10) and the back plate (20).

[0043] Additionally, the first connecting part (111) has a slimming groove formed on at least one of the other side and the upper part.

[0044] The second fastening part (112) is formed on one side of the first fastening part (111), more specifically on the side opposite to the surface where the first fastening part (111) contacts the furniture body (10), and a second fastening groove (112-1) into which a fastening screw (30) is inserted is formed so that the fastening screw (30) can be inserted into the first fastening part (111) through the second fastening groove (112-1). Here, the first fastening part (111-1) and the second fastening part (112-1) can be formed at a position that allows the fastening screw (30) to be inserted into the fastening part (110) at a 45-degree angle.

[0045] Thus, the fastening part (110) has a double structure including a first fastening part (111) and a second fastening part (11) protruding from one side of the first fastening part (112), so that when a fastening screw (30) is fastened to the fastening part (110), damage to the fastening part (110) can be reduced.

[0046] The wing (120) extends from the upper part of the fastening part (110), more specifically, from the upper part of the first fastening part (111), in the direction opposite to the second fastening part (112), in the direction of the surface where the first fastening part (111) contacts the furniture body (10), and is inserted into the back panel groove (11) of the furniture body (10). When the back panel (20) is inserted and coupled into the back panel groove (11), the wing fills the empty space of the remaining back panel groove (11), thereby minimizing the gap of the back panel (20) and preventing it from shaking, and thus preventing the back panel (20) from coming off the back panel groove (11). This strengthens the fixation of the back panel (20) without conventional fasteners and prevents the problem of the furniture frame becoming warped overall when used for a long period after storing heavy objects.

[0047] The weight reduction groove (130) is formed in at least one part of the other side and upper part of the first fastening part (111), more specifically, in at least one of the other side and upper part of the first fastening part (111) spaced apart from the first fastening groove (111-1), thereby preventing shrinkage of the back plate fastening bracket (100), more specifically, the fastening part (110), while allowing maximum cost reduction to be achieved while being less affected by structural impact (reduction in strength).

[0048] The wing support member (140) is formed by extending from the fastening member (110), more specifically, the first fastening member (111), at the lower end of the wing (120) to support the wing (120), thereby preventing the wing (120) from being damaged by shaking of the back plate (20) and preventing the back plate (20) from shaking.

[0049] A back plate fastening bracket (100) according to one embodiment of the present invention is manufactured by injection molding a polyamide-based composite material in which polyamide (polyamide 6, PA6), modified polypropylene (m-PP), and a compatibilizer are melt-blended.

[0050] Specifically, the back plate fastening bracket (100) is manufactured by injection molding a polyamide-based composite material in which 85 to 95 wt% of polyamide (polyamide 6, PA6), 5 to 15 wt% of modified polypropylene (m-PP), and 3 to 5 phr (per hundred resin) of compatibilizer per 100 wt of polyamide (polyamide 6, PA6) and modified polypropylene (m-PP).

[0051] Modified polypropylene (m-PP) of polyamide-based composite materials is produced by reaction extrusion by adding 0.03 to 0.05 phr (per hundred resin) of a radical initiator, 2 to 4 phr (per hundred resin) of a multifunctional modifier trimethylolpropane trimethacrylate (TMPTMA) and 1 phr (per hundred resin) of divinylbenzene (DVB) per 100 wt% of polypropylene (PP).

[0052] The commercially available polyamide-based composite material is at least one of maleic anhydride-grafted polypropylene (MA-g-PP) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS).

[0053] Figure 4 is a graph showing the results of evaluating moldability according to the radical initiator content of modified polypropylene (m-PP) used to manufacture a back plate fastening bracket according to one embodiment of the present invention.

[0054] FIG. 5 is a graph showing the results of evaluating the physical properties of modified polypropylene (m-PP) according to the content of a multifunctional modifier in the modified polypropylene (m-PP) used to manufacture a back plate fastening bracket according to one embodiment of the present invention. Here, (a) is moldability, (b) is impact strength, (c) is flexural modulus, and (d) is tensile strength.

[0055] FIG. 6 is a graph showing the results of evaluating the physical properties of modified polypropylene (m-PP) according to the process screw speed used to manufacture a back plate fastening bracket according to one embodiment of the present invention. Here, (a) is the formability, (b) is the impact strength, (c) is the flexural modulus, and (d) is the tensile strength.

[0056] FIG. 7 is a graph showing the results of evaluating physical properties according to the content of polyamide (polyamide 6, PA6) and modified polypropylene (m-PP) of a polyamide-based composite material used to manufacture a back plate fastening bracket according to one embodiment of the present invention. Here, (a) is moldability, (b) is impact strength, (c) is flexural modulus, and (d) is tensile strength.

[0057] FIGS. 8 and 9 are graphs showing the results of evaluating physical properties according to the type and content of a polyamide-based composite material used to manufacture a back plate fastening bracket according to an embodiment of the present invention. Here, (a) is moldability, (b) is impact strength, (c) is flexural modulus, and (d) is tensile strength.

[0058] The invention will be explained in more detail below based on FIGS. 4 to 9 and the embodiments and comparative examples of the present invention.

[0059] For Comparative Example 1, Lotte Chemical’s JM350 (MI = 10 g / 10 min @ 230 ℃, 2.16 kg) was used as the polypropylene (PP). For Examples 1 to 4, Lotte Chemical’s JM350 (MI = 10 g / 10 min @ 230 ℃, 2.16 kg) was mixed with Akzonobel’s Perkadox 14 (PK-14) as a radical initiator as shown in Table 1 below. After mixing, reactive extrusion was performed on a co-rotating type twin-screw extruder (Bautek, BA-19, L / D=40, 19 Φ) at a feeder-to-die temperature of 165–190 ℃ and a process screw speed of 150 rpm. The resulting strand was then used to manufacture pellets using a strand pelletizer (Bautek, BA-PLT) and then at 80 ℃ After drying in a vacuum dryer for 24 hours, standard specimens conforming to ASTM standards were prepared using a vertical injection molding machine (Heunghwa Machinery, HVM-25VS). Formability was measured using a Melt Index (MI, Tinius Olsen, MP600) according to ASTM D1238 under conditions of 235°C and 2.16 kg. Impact strength was evaluated using an Izod impact tester (Qmesys, QM700A) by notching impact specimens (V-shaped, 2.54 mm) according to ASTM D256. Flexural modulus was evaluated using a universal testing machine (UTM, Tinius Olsen, H5KT) at a speed of 5 mm / min according to ASTM D790, and tensile strength was evaluated using a universal testing machine (UTM, Tinius Olsen, H5KT) according to ASTM D638. It was evaluated at a speed of 50 mm / min. Here, the injection temperature and mold temperature were 170–190 ℃ and 40 ℃, respectively.

[0060] division PP (Comparative Example 1) m-PP1 (Example 1) m-PP2 (Example 2) m-PP3 (Example 3) m-PP4 (Example 4) JM350 (wt%) 100 100 100 100 100 PK-14 (phr) - 0.01 0.03 0.05 0.10

[0061] Referring to [Table 1] and Figure 4, the melt flow index (MI) of modified polypropylene (m-PP) continuously increased as the radical initiator content increased. This is because the molecular weight of polypropylene (PP) decreases due to the β-scission reaction.

[0062] In particular, it can be seen that the melt flow index (MI) of modified polypropylene (m-PP) increases rapidly when the radical initiator content is added at 0.1 phr (per hundred resin) or more per 100 wt of polypropylene (PP), as in m-PP4 (Example 4), so it is expected that the mechanical properties of modified polypropylene (m-PP) will deteriorate significantly due to the decrease in molecular weight. However, it can be seen that when the radical initiator content is 0.01 phr (per hundred resin) per 100 wt of polypropylene (PP), as in m-PP1 (Example 1), there is no significant difference from the melt flow index (MI) of polypropylene (PP).

[0063] Therefore, it can be confirmed that the radical initiator content of 0.03 to 0.05 phr (per hundred resin) is a content that improves the melt flow index (MI) and ensures the moldability required to manufacture the back plate fastening bracket (100) by injection molding.

[0064] Examples 5 to 10 were prepared as in Example 3 and evaluated in the same manner after combining the polyfunctional modifiers, Trimethylolpropane trimethacrylate (TMPTMA, trifunctional modifier) ​​from Sigma Aldrich and Divinylbenzene (DVB, difunctional modifier) ​​from Samchun as shown in Table 2.

[0065] division PP (Comparative Example 1) m-PP3 (Example 3) m-PP5 (Example 5) m-PP6 (Example 6) m-PP7 (Example 7) m-PP8 (Example 8) m-PP9 (Example 9) m-PP10 (Example 10) JM350 (wt%) 100 100 100 100 100 100 100 100 PK-14 (phr) - 0.05 0.05 0.05 0.05 0.05 0.05 0.05 TMPMTA (phr) - - 3 5 - - 2 4 DVB (phr) - - - - 3 5 1 1

[0066] Referring to [Table 2] and Figure 5, it can be seen that m-PP3 (Example 3), to which only a radical initiator was added to polypropylene (PP), has an increased melt flow index (MI) and decreased mechanical properties. This is a result of the decrease in molecular weight due to the β-scission reaction of polypropylene (PP).

[0067] On the other hand, as the content of a multifunctional modifier (at least one of TMPTMA and DVB) along with a radical initiator (0.05 phr) per 100 wt of polypropylene (PP) increased, the melt flow index (MI) of the modified polypropylene (m-PP) decreased and the mechanical properties increased. This is because the molecular weight of polypropylene (PP) increased due to the inhibition of the β-scission reaction and crosslinking reaction caused by the addition of the multifunctional modifier.

[0068] It can be seen that m-PP5 (Example 5) and m-PP6 (Example 6), which are modified polypropylene (m-PP) with trimethacrylate (Trimethylolpropane trimethacrylate, TMPTMA) added alone, have a high melt flow index (MI), but only slightly improved mechanical properties.

[0069] On the other hand, m-PP7 (Example 7) and m-PP8 (Example 8), which are modified polypropylene (m-PP) with divinylbenzene (DVB) added alone, showed the best mechanical properties, but there is a problem that injection molding is difficult because the melt flow index (MI) is very low.

[0070] It can be confirmed that m-PP9 (Example 9) and m-PP10 (Example 10), which are modified polypropylene (m-PP) with trimethylolpropane trimethacrylate (TMPTMA) and divinylbenzene (DVB) added together, have lower mechanical properties but higher melt flow index (MI) than m-PP7 (Example 7) and m-PP8 (Example 8) with divinylbenzene (DVB) added alone, and have lower melt flow index (MI) but superior mechanical properties than m-PP5 (Example 5) and m-PP6 (Example 6) with trimethylolpropane trimethacrylate (TMPTMA) added alone.

[0071] In addition, it can be confirmed that m-PP9 (Example 9) and m-PP10 (Example 10), which are modified polypropylene (m-PP) with trimethacrylate (Trimethylolpropane trimethacrylate, TMPTMA) and divinylbenzene (DVB) added together, exhibit superior moldability and mechanical properties compared to unmodified polypropylene (polypropylene, PP (Comparative Example 1)).

[0072] Therefore, considering both formability and mechanical properties (impact strength, flexural modulus, tensile strength), m-PP9 (Example 9) and m-PP10 (Example 10), which are modified polypropylene (m-PP) with both trimethacrylate (Trimethylolpropane trimethacrylate, TMPTMA) and divinylbenzene (DVB) added, may be the optimal modified polypropylene (m-PP) compositions.

[0073] Examples 11 and 12 were prepared by varying only the speed of the process screw during reactive extrusion compared to Example 9 as shown in Table 3 below, and were evaluated in the same way.

[0074] division m-PP9(A, Example 11) m-PP9(B, Example 9) m-PP9(C, Example 12) JM350 (wt%) 100 100 100 PK-14 (phr) 0.05 0.05 0.05 TMPTMA (phr) 2 2 2 DVB (phr) 1 1 1 Screw Speed ​​(rpm) 100 150 200

[0075] Referring to [Table 3] and Figure 6, it can be seen that as the process screw speed decreases, the melt flow index (MI) of modified polypropylene (m-PP) decreases and the mechanical properties increase. This is because as the process screw speed decreases, the residence time within the screw increases, leading to more crosslinking reactions.

[0076] In terms of mechanical properties, m-PP9 (A, Example 11), manufactured with a process screw speed of 100 rpm, is the best, but it has a low melt flow index (MI), making injection molding difficult.

[0077] Therefore, considering both formability and mechanical properties (impact strength, flexural modulus, tensile strength), m-PP9 (B, Example 9) and m-PP9 (C, Example 12), manufactured at process screw speeds of 150 rpm and 200 rpm, preferably m-PP9 (B, Example 9), may be the optimal modified polypropylene (m-PP) composition.

[0078] For Comparative Example 2, the polyamide (polyamide 6, PA6) used was Hyosung TNC's 1027BRT (MI = 30 g / 10 min @ 235 ℃, 2.16 kg, RV=2.7). For Examples 13 to 17, the modified polypropylene (m-PP9) of Example 9 was blended with the polyamide (polyamide 6, PA6) of Comparative Example 2 as shown in Table 4 below. A melt blend was performed in a co-rotating type twin-screw extruder (Bautek, BA-19, L / D=40, 19 Φ) at a feeder-to-die temperature of 220–240 ℃ and a process screw speed of 100 rpm. The resulting strands were then manufactured into pellets using a strand pelletizer (Bautek, BA-PLT), dried in an 80 ℃ vacuum dryer for 24 hours, and then processed using a vertical injection molding machine (Heunghwa Machinery, Standard specimens conforming to ASTM standards were prepared using an HVM-25VS, and formability was measured using a Melt Index (MI, Tinius Olsen, MP600) under conditions of 235°C and 2.16 kg according to ASTM D1238. Impact strength was evaluated by notching the impact specimen (V-shaped, 2.54 mm) using an Izod impact tester (Qmesys, QM700A) according to ASTM D256. Flexural modulus was evaluated using a Universal Testing Machine (UTM, Tinius Olsen, H5KT) at a speed of 5 mm / min according to ASTM D790, and tensile strength was evaluated using a Universal Testing Machine (UTM, Tinius Olsen, H5KT) at a speed of 50 mm / min according to ASTM D638. Here, the injection temperature and mold temperature were 230~250 ℃ and 80 ℃, respectively.

[0079] division PA6 (Comparative Example 2) m-PP9 (Example 9) PPA95 (Example 13) PPA90 (Example 14) PPA85 (Example 15) PPA80 (Example 16) PPA75 (Example 17) PA6 (wt%) 100 - 95 90 85 80 75 m-PP (wt%) - 100 5 10 15 20 25

[0080] Referring to [Table 4] and Figure 7, it can be seen that in all of Examples 9 and 13 to 17, when modified polypropylene (m-PP) was used, excellent moldability and mechanical properties (impact strength, flexural modulus, tensile strength) were observed compared to when polypropylene (PP) in the same amount as the modified polypropylene (m-PP) of Examples 9 and 13 to 17 was mixed with polyamide (polyamide 6, PA6).

[0081] In Examples 9 and 13 to 17, it can be seen that the impact strength increases as the content of modified polypropylene (m-PP) increases, which is because the influence of modified polypropylene (m-PP), which has superior impact strength compared to polyamide (polyamide 6, PA6, Comparative Example 2), becomes dominant.

[0082] However, in Examples 9 and 13 to 17, it can be seen that the flexural modulus and tensile strength decrease as the content of modified polypropylene (m-PP) increases, which is due to the influence of modified polypropylene (m-PP), which has lower flexural modulus and tensile strength than polyamide (polyamide 6, PA6, Comparative Example 2).

[0083] In addition, Examples 13 to 17 show significantly lower impact strength compared to Example 9, which may be due to the low compatibility between polyamide (polyamide 6, PA6) and modified polypropylene (m-PP).

[0084] When considering the correlation between mechanical properties (impact strength, flexural modulus, tensile strength) according to the content of modified polypropylene (m-PP), the content of modified polypropylene (m-PP) may be optimal at 5 to 15 wt%.

[0085] Examples 18 to 21 were prepared as in Example 15 and evaluated in the same manner as in Example 15 by mixing maleic anhydride-grafted polypropylene (MA-g-PP) from Lotte Chemical Co., Ltd., PH200 (content of grafted MA 2.5~5.0 wt%) as a compatibilizer as shown in Table 5 below.

[0086] division PA6 (Comparative Example 2) m-PP9 (Example 9) PPA85 (Example 15) PPA85S1 (Example 18) PPA85S3 (Example 19) PPA85S5 (Example 20) PPA85S7 (Example 21) PA6 (wt%) 100 - 85 85 85 85 85 m-PP (wt%) - 100 15 15 15 15 15 MA-g-SEBS (phr) - - - 1 3 5 7

[0087] Referring to [Table 5] and Figure 8, it can be seen that the melt flow index (MI) of the polyamide-based composite materials (Examples 18 to 21) continuously decreases as the content of the compatibilizer maleic anhydride-grafted polypropylene (MA-g-PP) increases. This may be a result of the grafting reaction between polyamide (polyamide 6, PA6) and modified polypropylene (m-PP) due to the high reactivity of the MA functional group.

[0088] On the other hand, it can be seen that the impact strength of the polyamide-based composite materials (Examples 18 to 21) continuously increases as the content of the compatibilizer maleic anhydride-grafted polypropylene (MA-g-PP) increases. This is because the interfacial bonding strength between polyamide (polyamide 6, PA6) and modified polypropylene (m-PP) is increased by the addition of the compatibilizer maleic anhydride-grafted polypropylene (MA-g-PP), thereby improving compatibility.

[0089] In addition, it can be observed that as the content of the compatibilizer maleic anhydride-grafted polypropylene (MA-g-PP) increases, the flexural modulus and tensile strength of the polyamide-based composite materials (Examples 18 to 21) initially increase and then continuously decrease. This is because compatibility is improved initially due to increased interfacial bonding strength between polyamide (polyamide 6, PA6) and modified polypropylene (m-PP), and subsequently, the influence of modified polypropylene (m-PP), which has lower flexural modulus and tensile strength, becomes dominant.

[0090] However, since the molecular weight of the commercial agent maleic anhydride-grafted polypropylene (MA-g-PP) is low, there may be limitations in improving the impact strength of the composite materials (Examples 18 to 21).

[0091] Examples 22 to 25 were prepared as in Example 15 and evaluated in the same manner by mixing maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS), which is Kraton’s FG1924 (grafted MA content 0.7~1.3 wt%), as a compatibilizer in Example 15 as shown in Table 6 below.

[0092] division PA6 (Comparative Example 2) m-PP9 (Example 9) PPA85 (Example 15) PPA85S1 (Example 22) PPA85S3 (Example 23) PPA85S5 (Example 24) PPA85S7 (Example 25) PA6 (wt%) 100 - 85 85 85 85 85 m-PP (wt%) - 100 15 15 15 15 15 MA-g-SEBS (phr) - - - 1 3 5 7

[0093] Referring to [Table 6] and Figure 9, it can be seen that the melt flow index (MI) of the polyamide-based composite materials (Examples 22 to 25) continuously decreases as the content of the compatibilizer maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS) increases. This is a result of the grafting reaction between polyamide (polyamide 6, PA6) and modified polypropylene (m-PP) due to the high reactivity of the MA functional group.

[0094] On the other hand, it can be seen that the impact strength of the polyamide-based composite materials (Examples 22 to 25) continuously increases as the content of the compatibilizer maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS) increases. This is because the interfacial bonding strength between the polyamide (polyamide 6, PA6) and the modified polypropylene (m-PP) increases with the addition of the compatibilizer maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS), thereby improving compatibility.

[0095] In addition, it can be observed that as the content of the compatibilizer maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS) increases, the flexural modulus and tensile strength of the polyamide-based composite materials (Examples 22 to 25) show a tendency to continuously decrease. This is because, despite the improvement in compatibility between polyamide (polyamide 6, PA6) and modified polypropylene (m-PP) due to the addition of maleic anhydride-grafted styrene-ethylene-butylene-styrene (MA-g-SEBS), the modified polypropylene (m-PP) has increased ductility and lower flexural modulus and tensile strength.

[0096] Consequently, the back plate fastening bracket (100) comprises 5 to 15 wt% of modified polypropylene (m-PP) produced by reaction extrusion with 85 to 95 wt% of polyamide (polyamide 6, PA6), 100 wt% of polypropylene (PP), 0.03 to 0.05 phr (per hundred resin) of a radical initiator per 100 wt of polypropylene (PP), 2 to 4 phr (per hundred resin) of a multifunctional modifier trimethylolpropane trimethacrylate (TMPTMA), and 1 phr (per hundred resin) of divinylbenzene (DVB), and polyamide (polyamide 6, PA6) and maleic anhydride-graft per 100 wt of modified polypropylene (m-PP). It may be produced by injection molding a polyamide-based composite material by melt blending 3 to 5 phr (per hundred resin) of a compatibilizer that is at least one of polypropylene (Maleic anhydride-grafted polypropylene, MA-g-PP) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (Maleic anhydride-grafted styrene-ethylene-butylene-styrene, MA-g-SEBS).

[0097] The back plate fastening bracket (100) is manufactured by injection molding a polyamide-based composite material with an impact strength of 100 J / m or more, a flexural modulus of 2,000 Mpa or more, and a tensile strength of 50 Mpa or more, as described above, so it is not easily damaged even after a large impact and a long time, and thus can stably maintain the back plate (20).

[0098] FIG. 10 is a flowchart of a method for manufacturing a back plate fastening bracket according to another embodiment of the present invention.

[0099] Referring to Fig. 10, in step S1010, a radical initiator and a multifunctional modifier are added to polypropylene (PP), and reactive extrusion is carried out in a co-rotating type twin-screw extruder (Bautek, BA-19, L / D=40, 19 Φ) at a temperature of 165–190 °C from the feeder to the die and a process screw speed of 150 rpm to produce modified polypropylene (m-PP).

[0100] In step S1020, a polyamide-based composite material is produced by melt blending polyamide (polyamide 6, PA6), modified polypropylene (m-PP), and a compatibilizer in a co-rotating type twin-screw extruder (Bautek, BA-19, L / D=40, 19 Φ) at a temperature of 220~240 ℃ from the feeder to the die and a process screw speed of 100 rpm.

[0101] In step S1030, a polyamide-based composite material is injection molded to produce a back plate fastening bracket (100).

[0102] Although embodiments according to the present invention have been described above, they are merely illustrative, and those skilled in the art will understand that various modifications and equivalent embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the following claims. Explanation of the symbols

[0104] 110 : Fastening part 120 : Wing 130: Rice removal groove 140: Wing support

Claims

Claim 1 A back panel fastening bracket for assembling a back panel to a furniture body, comprising: a fastening portion into which a fastening screw is inserted; and a wing extending from the upper portion of the fastening portion and inserted into the back panel groove of the furniture body into which the back panel is inserted, wherein the fastening portion comprises a first fastening portion having a first fastening groove formed in a part of the upper portion through which the inserted fastening screw exits, and a second fastening portion protruding from the surface opposite to the surface where the first fastening portion contacts the furniture body and having a second fastening groove formed into which the fastening screw is inserted. Claim 2 A back plate fastening bracket according to claim 1, characterized in that the first fastening groove is formed to extend to a part of the wing. Claim 3 A back plate fastening bracket according to claim 1, further comprising a slimming groove formed on a part of at least one of the other side and upper part of the first fastening part to prevent shrinkage of the back plate fastening bracket. Claim 4 A back plate fastening bracket according to claim 1, further comprising a wing support member formed extending from the fastening member at the lower end of the wing and supporting the wing.

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