WO2021075817A1 - Molded body, sandwich panel using same, method for manufacturing molded body, and method for manufacturing sandwich panel - Google Patents

Abstract

The present invention relates to a molded body and a method for manufacturing same, the molded body having a non-woven fiber assembly structure including two or more non-woven fiber assemblies and at least one bonding portion formed by bonding the non-woven fiber assemblies to each other, wherein the density (g/cm³) of the bonding portion is 2 to 4.5 times the density(g/cm³) of the non-woven fiber assemblies. In addition, the present invention relates to a sandwich panel and a method for manufacturing same, the sandwich panel comprising: a core layer; a skin layer laminated on at least one surface of the core layer; and a bonding layer for bonding the skin layer to the core layer, wherein the core layer is formed using the molded body.

Description

Molded body, sandwich panel using the same, method of manufacturing molded body, and method of manufacturing sandwich panel

The present invention relates to a molded article for a sandwich panel, a sandwich panel using the same as a core layer, a method of manufacturing the molded article, and a method of manufacturing a sandwich panel.

Conventional sandwich panels are used in various fields such as building materials because they have structural rigidity similar to that of metal panels and are effective in reducing weight.

In such a sandwich panel, a core layer (molded body) is formed between skin layers made of aluminum, iron, etc. to control the physical properties of the panel. For example, a foamed resin material is used for the core layer to increase the weight reduction effect of the panel, or a general resin, composite material, or balsa wood material is used to increase the mechanical strength of the panel.

However, such a sandwich panel has a limitation in product application due to insufficient weight reduction and insufficient mechanical strength, and not excellent elongation. In addition, in the case of forming a panel by applying an adhesive between the skin layer and the core layer, there is a problem in that the interlayer bonding force is weak and the moldability during processing is poor.

As a background technology related to the present invention, there is Korean Patent Publication No. 10-2017-0140111, and a sandwich panel and a manufacturing method thereof are disclosed in the document.

In the case of the sandwich panel, a sandwich panel having physical properties such as high density and high flexural strength and tensile strength was secured, but it was difficult to uniformly manufacture the nonwoven fabric used as the core material of the sandwich panel with only one nonwoven fiber aggregate layer. In addition, when a core material is manufactured by bonding two or more layers of a nonwoven fiber aggregate through a physical method such as needle punching or an adhesive film, there is a problem that an interface peeling phenomenon occurs.

[Prior technical literature]

[Patent Literature]

(Patent Document 1) Korean Laid-Open Patent Publication No. 10-2017-0140111, a sandwich panel and a manufacturing method thereof

In order to solve the above problem, the present inventors studied a method of bonding between interfaces of a nonwoven fiber aggregate used as a core material for a sandwich panel through a flame lamination process, and a sandwich panel including a core material manufactured through the flame lamination process. The present invention has been completed.

According to the first aspect of the present invention,

It is a non-woven fiber aggregate structure comprising two or more non-woven fiber aggregates and at least one junction in which the non-woven fiber aggregate is bonded to each other, and the density of the junction (g/cm ³ ) is the density of the non-woven fiber aggregate (g/cm ³ ) It provides a molded body, which is 2 to 4.5 times larger.

In one embodiment of the present invention, the non-woven fiber aggregate structure may be a structure in which two or more non-woven fiber aggregates are bonded by heat fusion.

In one embodiment of the present invention, the nonwoven fiber assembly may be formed by bonding a nonwoven fiber on a web or a sheet with an adhesive or bonding using a thermoplastic fiber.

In one embodiment of the present invention, the interface peel strength of the junction may be 250 to 600 psi.

In one embodiment of the present invention, the density of the junction may be ^{0.3 to 0.9 g/cm 3.}

In one embodiment of the present invention, the nonwoven fiber aggregate may include polyester fibers.

In one embodiment of the present invention, the polyester fiber may be any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

According to the second aspect of the present invention,

Core layer; A skin layer laminated on one or more surfaces of the core layer; And an adhesive layer bonding the core layer and the skin layer, wherein the core layer uses the molded body.

In one embodiment of the present invention, the skin layer may be any one or more selected from the group consisting of aluminum, iron, stainless steel (SUS), magnesium, and electrogalvanized steel sheet (EGI).

In one embodiment of the present invention, the adhesive layer may include at least one of an olefin-based adhesive, a urethane-based adhesive, an acrylic adhesive, and an epoxy-based adhesive.

In one embodiment of the present invention, the adhesive layer may include a first adhesive layer including high-density polyethylene (HDPE) and a second adhesive layer including low-density polyethylene (LDPE).

According to the third aspect of the present invention,

a) preparing two or more nonwoven fiber aggregates; And b) bonding the interfaces of the two or more nonwoven fiber aggregates to each other through a flame lamination process.

In one embodiment of the present invention, step b) may be a step of bonding the interface of the nonwoven fiber assembly through a flame lamination process having a flame temperature of 700 to 1000°C and a heating value of 15,000 to 70,000 kcal.

In one embodiment of the present invention, in step b), the interfacial peel strength of the bonding portion of the nonwoven fiber assembly bonded through the flame lamination process may be 250 to 600 psi.

In one embodiment of the present invention, in step b), the junction density of the nonwoven fiber assembly bonded through the flame lamination process may be ^{0.3 to 0.9 g/cm 3.}

According to the fourth aspect of the present invention,

a) preparing two or more nonwoven fiber aggregates; b) manufacturing a core layer by bonding the interfaces of the two or more nonwoven fiber aggregates to each other through a flame lamination process; c) forming an adhesive layer on at least one surface of the core layer; And d) forming a skin layer on the adhesive layer.

In one embodiment of the present invention, step d) may form a skin layer by laminating a core layer, an adhesive, and a skin layer, followed by photocuring or thermal curing.

In one embodiment of the present invention, the thermal curing may be performed at 50 to 110° C. for 5 minutes to 2 hours.

In one embodiment of the present invention, the thermal curing may be performed at room temperature for 1 to 10 hours.

In one embodiment of the present invention, the adhesive layer comprises a first adhesive layer comprising high-density polyethylene (HDPE) and a second adhesive layer comprising low-density polyethylene (LDPE), and the core layer is bonded to the first adhesive layer, , The skin layer may be bonded to the second adhesive layer.

The present invention provides a molded body for a core material of a sandwich panel manufactured through a flame lamination process for minimizing the delamination between interfaces of a nonwoven fiber assembly, a sandwich panel including the same, a method of manufacturing a molded body, and a method of manufacturing a sandwich panel.

Through this, compared to the method of manufacturing the core material by bonding the interface of the nonwoven fiber aggregate through the existing needle punching process or the adhesive film, the core material having the same or excellent peeling force and the sandwich panel including the same maintain uniform quality. It has the advantage of not only being able to produce at high speed, but also of easy maintenance and maintenance of production facilities.

1 is a schematic diagram of a sandwich panel according to the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

Hereinafter, a molded article and a sandwich panel according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As a result of the experiment of the present inventors, in the case of a core material used in a conventional sandwich panel, it was difficult to uniformly manufacture a nonwoven fiber aggregate structure of a certain weight or more composed of one layer. Therefore, in order to manufacture a high-weight nonwoven fiber aggregate structure composed of two or three layers, a core material was manufactured by bonding the interface by a needle punching process, which is a physical method, or by introducing an adhesive film between the interfaces. However, the needle punching process has a limitation in processing speed and has a problem in that there is a large variation in quality and weight. In addition, in the case of lamination through an adhesive film, there is a problem that the production process is complicated and the peeling force of the core material is low, so there is a need for a study on the bonding method between the interface of the nonwoven fiber aggregate of the core material for a sandwich panel and improvement of peeling force.

However, the present inventors bonded the interfaces of the nonwoven fiber assembly used as the core material for the sandwich panel using a flame lamination process, and studied the optimum process conditions to improve the interface peeling force, thereby preventing the interfacial peeling phenomenon inside the core material. It has come to produce a sandwich panel containing a minimized core layer (molded body).

Molded body

The molded article according to the present invention is a non-woven fiber aggregate structure comprising at least two non-woven fiber aggregates and at least one joint portion in which the non-woven fiber aggregates are bonded to each other. In addition, the density of the junction ^{(g/cm 3} ) is 2 to 4.5 times ^{the density (g/cm 3} ) of the nonwoven fiber aggregate. The density (g/cm ³ ) is defined by the following equation.

Density (g/cm ³ ) = Measured mass (g) / Measured volume (cm ³ )

With respect to the joint, the molded body is cut into a certain size (25mm X 25mm), the interface of the joint is separated, the thinnest joint thickness is measured, and the volume and mass can be measured. The joint portion may be thermally fused so that voids may not exist.

The non-woven fiber aggregate structure may be a structure in which two or more non-woven fiber aggregates are bonded by heat fusion. One side of the nonwoven fiber assembly is heated with a laminating flame generator to make the interface in a molten state, and then two or more interfaces of the nonwoven fiber assembly can be bonded together and thermally fused using the bonding force at this time. Through the flame lamination process using the flame generator, the production speed can be improved compared to the conventional needle punching process, which is a physical method, and there is an advantage in that the peeling force between the interfaces can be improved than the method of bonding the interface through an adhesive film.

Interfacial peel strength of the junction is 250 psi or more, 275 psi or more, 300 psi or more, 325 psi or more, 350 psi or more, 375 psi or more, 400 psi or more, 425 psi or more, 450 psi or more, 475 psi or more, 500 psi or more I can. In addition, the interface peel strength of the junction may be 600 psi or less, 595 psi or less, 590 psi or less, 585 psi or less, 580 psi or less.

Since the interfacial peel strength range is satisfied, peeling between the interfaces of the nonwoven fiber aggregate is prevented, and mechanical properties sufficient for use as a core material for a sandwich panel can be obtained.

The density of the junction is 0.3 g/cm ³ or more, 0.35 g/cm ³ or more, 0.4 g/cm ³ or more, 0.45 g/cm ³ or more, 0.5 g/cm ³ or more, 0.55 g/cm ³ or more, 0.6 g/ It may be ^{cm 3} or more, 0.65 g/cm ^{3 or more.} In addition, the density of the junction may be 0.9 g/cm ³ or less, 0.85 g/cm ³ or less, or 0.8 g/cm ³ or less.

In the case of manufacturing a molded article through a flame lamination process, there is an advantage in that the quality of the molded article used as a core material of a sandwich panel can be uniformly manufactured as it is easy to perform the process to satisfy the above density range.

The molded article according to the present invention comprises a polyester fiber and a binder, and consists of a nonwoven fiber aggregate structure.

In the present invention, the term'non-woven fiber aggregate' refers to a non-woven fiber on a web or a sheet bonded with an adhesive or bonded using a thermoplastic fiber, and the molded body according to the present invention is a fiber Has a nonwoven fiber aggregate entangled with each other, all or part of the polyester fiber is fused by the binder, and thus, natural pores are included in the molded body, resulting in good breathability and improved weight reduction. have. In other words, since the fibers have natural pores formed by entangled with each other, unlike the case where pores are artificially formed by additives such as a foaming agent, since it is a non-foaming core, manufacturing cost can be reduced and the foaming process can be omitted. Efficiency can also be improved.

It is preferable that the average length of the polyester-based fibers included in the molded article according to the present invention is 5 to 100 mm, and when the average length of the fibers is less than 5 mm, it may be difficult to expect the effect of high elongation due to the short length of the fibers. Conversely, when it exceeds 100 mm, the amount of fibers entangled with each other increases, and thus the space occupied by the gap in the molded body may be reduced. In addition, when it exceeds 100mm, when the molded article is manufactured, the fibers are not smoothly dispersed, and the physical properties of the molded article may be deteriorated.

The binder included in the molded body may be a non-hygroscopic copolymer resin or a hygroscopic copolymer resin.

In particular, the non-hygroscopic copolymer resin used in the present invention refers to a resin having a property that does not absorb moisture in the air, and specifically, based on the molded article of the present invention manufactured using the resin, 85°C temperature and relative The weight change rate (that is, the increase rate of the moisture content) of the molded article after being allowed to stand at 85% humidity for 100 hours may be less than 0.1%, preferably less than 0.08%, more preferably less than 0.07%.

In general, since the moisture absorption of PET fibers contained in the molded body is less than 0.05%, the weight change rate of the molded body exceeds 0.05%, which means that the amount of moisture absorbed by the binder, another component in the molded body, is significant. do. In this regard, with the non-hygroscopic copolymer resin used in the present invention, the weight change rate (that is, the increase rate of the moisture content) of the molded article after being left for 100 hours at 85°C temperature and 85% relative humidity based on the final manufactured molded article is less than 0.1%. , Preferably less than 0.08%, more preferably less than 0.07%.

As such a non-hygroscopic copolymer resin, an ester-based resin, a diol-based monomer having strong crystallinity and excellent elasticity, and an acidic component capable of imparting flexibility are copolymerized together, and satisfying the above water absorption may be used.

Specifically, the polyester fiber may be any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and as the diol-based monomer, neo In the group consisting of pentyl glycol, diethylene glycol, ethylene glycol, poly(tetramethylene) glycol, 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, etc. Any one or more selected may be used, and any one or more selected from the group consisting of isophthalic acid, adipic acid, 2,6-naphthalenedicarboxylic acid, sebacic acid, succinic acid, and the like may be used as the acid component.

All or part of the polyester fiber included in the molded article according to the present invention is fused by a binder that is a non-hygroscopic resin, and the binder may have a melting point of 160°C or higher.

The molded article according to the present invention has an apparent density of 0.5 to 0.8 g/cm ³ . Since it satisfies the above density range, it can have sufficient mechanical strength for use in packaging materials for large cargoes.

Since the molded article according to the present invention satisfies the mechanical strength as described above, it is included as a core layer in a sandwich panel, and structural materials for home appliances (TV back cover, washing machine board, etc.), interior and exterior boards for construction, interior and exterior materials for automobiles, and trains It can be used as interior and exterior materials for ships/aircrafts (boards such as dividers), various dividers boards, elevator structures, etc.

The nonwoven fiber aggregate according to the present invention may include polyester-based fibers.

The polyester fiber may be any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

In addition, the nonwoven fiber assembly may further include a sheath-core type bicomponent fiber. The sheath-core bicomponent fiber may include a core part of a polyester fiber; And a sheath part which is a non-hygroscopic copolymer resin surrounding the core part. The sheath-core bicomponent fiber, which was introduced in the manufacturing step of the molded article according to the present invention, remains in a state in which the resin of the sheath portion is not melted, and thus may be included in the molded article according to the present invention.

Among the cis-core bicomponent fibers, the core portion of the polyester fiber may be any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. have.

Among the cis-core bicomponent fibers, the sheath portion may use the same non-hygroscopic copolymer resin as the binder included in the molded article according to the present invention.

Specifically, the non-hygroscopic copolymer resin refers to a resin having a property that does not absorb moisture in the air, and specifically, based on the molded article of the present invention manufactured using the resin, 100 at 85°C temperature and 85% relative humidity. The weight change ratio (that is, the increase rate of the moisture content) of the molded article after leaving for a period of time may be less than 0.1%, preferably less than 0.08%, more preferably less than 0.07%.

In general, since the moisture absorption of PET fibers contained in the molded body is less than 0.05%, the weight change rate of the molded body exceeds 0.05%, which means that the amount of moisture absorbed by the binder, another component in the molded body, is significant. do. In this regard, with the non-hygroscopic copolymer resin used in the present invention, the weight change rate (that is, the increase rate of the moisture content) of the molded article after being left for 100 hours at 85°C temperature and 85% relative humidity based on the final manufactured molded article is less than 0.1%. , Preferably less than 0.08%, more preferably less than 0.07%.

As such a non-hygroscopic copolymer resin, an ester-based resin, a diol-based monomer having strong crystallinity and excellent elasticity, and an acidic component capable of imparting flexibility are copolymerized together, and satisfying the above water absorption may be used.

Specifically, the polyester fiber may be any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and as the diol-based monomer, neo In the group consisting of pentyl glycol, diethylene glycol, ethylene glycol, poly(tetramethylene) glycol, 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, etc. Any one or more selected may be used, and any one or more selected from the group consisting of isophthalic acid, adipic acid, 2,6-naphthalenedicarboxylic acid, sebacic acid, succinic acid, and the like may be used as the acid component.

The sheath-core bicomponent fiber is prepared by melt spinning and stretching using the components of the core part and the components of the sheath part.

In addition, when the non-hygroscopic resin is used as a sheath component of a sheath-core bicomponent fiber, flexural strength and tensile strength are improved, and a molded article can be manufactured by a dry process, which makes it easier to manufacture a high-density molded layer. In addition, if it is used for packaging of large cargoes, it is possible to prevent sagging of the nonwoven fabric due to good physical properties and shape retention even in an atmosphere of high temperature and high humidity.

In addition, the molded article according to the present invention may further include a filler such as glass fiber, carbon fiber, polymer fiber, and the like. In addition, a flame retardant such as a brominated organic flame retardant may be further included. In addition, additives such as an impact modifier and a heat stabilizer may be further included.

Manufacturing method of molded body

The method of manufacturing the molded article according to the present invention may be manufactured by the following method.

The method of manufacturing the core layer according to the present invention comprises the steps of: a) preparing two or more nonwoven fiber aggregates; And b) bonding the interfaces of the two or more nonwoven fiber aggregates to each other by a flame lamination process.

First, in step a), two or more nonwoven fiber aggregates are prepared. In order to prepare the nonwoven fiber aggregate, a nonwoven fiber aggregate including polyester fibers is prepared. As the polyester fiber, any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate may be used.

In addition, it is possible to manufacture a nonwoven fiber assembly further comprising a sheath-core type bicomponent fiber. In this case, (A) a polyester fiber and (B) a core part of the polyester fiber, and a sheath part, which is a non-hygroscopic copolymer resin surrounding the core part, is a sheath-core type (sheath). -core type) After mixing bicomponent fibers, it can be heated and pressurized to prepare a nonwoven fiber assembly. In this case, (A) polyester fibers and (B) sheath-core bicomponent fibers may be mixed and used in a weight ratio of 1:99 to 80:20. When the content of the (B) sheath-core bicomponent fiber is less than the above range, the fusion between the fibers is not sufficient, so that the physical properties of the nonwoven fiber assembly may be degraded.

The production of the molded body may be performed using a conventional method using a nonwoven fiber assembly. For example, it is possible to manufacture a molded body through a needle punching process, a flame lamination process, an adhesive film introduction, etc., and preferably, after manufacturing the nonwoven fiber assembly, a flame lamination process may be performed to manufacture the molded body. It is not limited.

Thereafter, step b) is a step of bonding the interfaces of the two or more nonwoven fiber aggregates to each other through a flame lamination process.

The step b) may be a step of bonding the interface of the nonwoven fiber assembly through a flame lamination process having a flame temperature of 700 to 1000 °C, preferably a flame temperature of 770 to 930 °C, more preferably a flame temperature of 830 to 910 °C. . When the flame temperature is less than 700° C., the interface of the nonwoven fiber assembly between the flame lamination processes is not sufficiently melted to have bonding strength, and thus there is a problem that peeling occurs after bonding between the interfaces. In addition, when the flame temperature is 1000°C or higher, yellowing occurs in the nonwoven fiber assembly, and there is a problem in that the peel strength is deteriorated.

The step b) may be a step of bonding the interface of the nonwoven fiber aggregate through a flame lamination process having a calorific value of 15,000 to 70,000 kcal, preferably a calorific value of 19000 to 70000 kcal, and more preferably a calorific value of 35000 to 50000 kcal. The calorific value is a value measured by using a thermal differential scanning calorimeter (DSC) to measure the amount of heat generated by burning the interface of the nonwoven fiber assembly between flame lamination processes. If the range of the calorific value is satisfied, the interface is melted through the combustion process and thermally fused during subsequent bonding to achieve a sufficient peeling force to prevent the peeling phenomenon.

The step b) may be a step of bonding the interface of the nonwoven fiber aggregate through a flame lamination process having an excess air rate of 0.5 to 1.1, preferably an excess air rate of 0.7 to 1.1, and more preferably an excess air rate of 0.9 to 1.1. . In the present specification, the excess air rate is defined as the ratio of the actual air volume to the theoretical air volume. The closer the excess air rate is to 1, the more complete combustion is, and the further away from 1, the more incomplete combustion.

The step b) is a nonwoven fiber assembly through a flame lamination process having a gas flow rate of 1.5 to 7.5 Nm ³ /h, preferably a gas flow rate of 3.0 to 7.5 Nm ³ /h, and more preferably a gas flow rate of 4.5 to 7.5 Nm ^{3 /h.} It may be a step of bonding the interface of. When the gas flow rate is 1.5 Nm ³ /h or less, there is a problem in that thermal fusion at the interface is not properly performed and peeling easily occurs because the amount of heat generated is insufficient. In addition, when the gas flow rate is 7.5 Nm ³ /h or more, carbonization of the material occurs at the interface due to an excessively high calorific value, so that not only the peeling properties but also the mechanical properties are deteriorated.

In step b), the interfacial peel strength of the bonded portion of the nonwoven fiber assembly bonded through the flame lamination process is 250 psi or more, 275 psi or more, 300 psi or more, 325 psi or more, 350 psi or more, 375 psi or more, 400 psi or more. , 425 psi or more, 450 psi or more, 475 psi or more, 500 psi or more. In addition, the interface peel strength of the junction may be 600 psi or less, 595 psi or less, 590 psi or less, 585 psi or less, 580 psi or less.

Since the interfacial peel strength range is satisfied, peeling between the interfaces of the nonwoven fiber aggregate is prevented, and mechanical properties sufficient for use as a core material for a sandwich panel can be obtained.

In the step b), the density of the junction of the nonwoven fiber assembly bonded through the flame lamination process is 0.3 g/cm ³ or more, 0.35 g/cm ³ or more, 0.4 g/cm ³ or more, 0.45 g/cm ³ or more, 0.5 It may be g/cm ³ or more, 0.55 g/cm ³ or more, 0.6 g/cm ³ or more, and 0.65 g/cm ^{3 or} more. In addition, the density of the junction may be 0.9 g/cm ³ or less, 0.85 g/cm ³ or less, or 0.8 g/cm ³ or less.

In the case of manufacturing a molded article through a flame lamination process, there is an advantage in that the quality of the molded article used as a core material of a sandwich panel can be uniformly manufactured as it is easy to perform the process to satisfy the above density range.

In step b), the process speed of flame lamination may be 2 to 8 m/min, preferably 3 to 7 m/min, more preferably 4 to 6 m/min. When the process speed is 2 m/min or less, there is a problem that the physical properties are deteriorated due to carbonization of the material as an excessively high calorific value is applied to the part where fusion occurs, and if it is 8 m/min or more, the applied calorific value is not sufficient. There may be a problem in that thermal fusion is not properly performed. Through the flame lamination process, the peeling force is improved through an improved process speed compared to the conventional needle punching process, while at the same time, it has the advantage of having a fast production speed of the core material.

After the flame lamination process under the above conditions, the nonwoven fabric is transferred to a heating press, and then heated and pressurized under a temperature condition of 170 to 210°C and a pressure of 1 to 10 MPa to manufacture a molded article.

The heating press is not particularly limited as long as it is generally used in the industry, and as a specific example, a double belt press or the like may be used.

Sandwich panel

Referring to Figure 1, the sandwich panel according to the present invention is a core layer; A skin layer laminated on one or more surfaces of the core layer; And an adhesive layer bonding the core layer and the skin layer, wherein the core layer uses the molded body.

The core layer 10 of the sandwich panel according to the present invention is composed of the molded body according to the present invention as discussed above. It is preferable that the thickness of the core layer is 0.1 to 10 mm. If the thickness is less than 0.1mm, it is difficult to maintain excellent mechanical strength, and if the thickness exceeds 10mm, there is a problem that the formability is deteriorated during bending of the sandwich panel or deep drawing molding.

The sandwich panel according to the present invention includes a skin layer 20 laminated on one or more surfaces of the core layer 10.

The skin layer 20 of the sandwich panel according to the present invention may be formed of a metal material, preferably aluminum, iron, stainless steel (SUS), magnesium, electrogalvanized steel sheet (EGI), and hot-dip galvanized steel sheet (GI ) It may include any one or more selected from the group consisting of. For example, in order to have excellent formability and flexural stiffness, the skin layer 20 including an electrogalvanized steel sheet (EGI) may be applied to the sandwich panel. In addition, in order to reduce weight, the skin layer 20 including aluminum may be applied to the sandwich panel.

The thickness of the skin layer 20 may be 6% or less of the thickness of the entire panel. The skin layer of the conventional sandwich panel had a problem that the thickness of the skin layer had to be thick due to the low mechanical strength of the core material, and thus there was a problem that the weight of the sandwich panel increased. However, the sandwich panel according to the present invention has a mechanical strength of the core material. As the strength is improved, the thickness of the skin layer can be reduced to 6% or less compared to the thickness of the entire panel, thereby making it possible to reduce weight.

The sandwich panel according to the present invention includes an adhesive layer for bonding the core layer 10 and the skin layer 20 to each other.

The adhesive layer of the sandwich panel according to the present invention is applied between the core layer 10 and the skin layer 20 to adhere the core layer 10 and the skin layer 20. It is preferable to apply the adhesive layer to a uniform thickness in consideration of the viscosity. In the present invention, the core layer 10 and the skin layer 20 may be laminated and then cured to manufacture a sandwich panel, or the core layer 10 and the skin layer 20 may be laminated and then thermally compressed Sandwich panels can be manufactured. At this time, as the adhesive penetrates into the core layer 10 in the process of curing or thermocompression bonding, the skin layer 20 and the core layer 10 are mechanically bonded as well as chemical bonds with the components constituting the core layer 10. ) Has the effect of improving the adhesion. The chemical bonding means that the adhesive becomes a covalent bond, a hydrogen bond, a Van der Waals bond, an ionic bond, or the like with the upper and lower surfaces of the core layer.

The mechanical bonding refers to a form in which the adhesive penetrates into the core layer and physically hangs as if the rings are hanging together. This form is also called mechanical interlocking. The adhesive permeates the upper and lower surfaces of the core layer 10 by the natural pores contained in the core layer 10.

The adhesive constituting the adhesive layer may include at least one of an olefin-based adhesive, a urethane-based adhesive, an acrylic adhesive, and an epoxy-based adhesive. As the olefin-based adhesive, at least one selected from the group consisting of polyethylene, polypropylene, and amorphous polyalphaolefin adhesive may be used. The urethane-based adhesive may be used without limitation as long as it includes a urethane structure (-NH-CO-O-). The acrylic adhesive may include at least one of a polymethyl methacrylate adhesive, a hydroxy group-containing polyacrylate adhesive, and a carboxy group-containing polyacrylate adhesive. The epoxy adhesive includes at least one of bisphenol-A type epoxy adhesive, bisphenol-F type epoxy adhesive, novolac epoxy adhesive, linear aliphatic epoxy resins, and cycloaliphatic epoxy resins. Can include.

In addition, the adhesive may include a photocurable adhesive, a hot melt adhesive, or a thermosetting adhesive, and any one of a photocuring method and a thermosetting method may be used. For example, a sandwich panel can be manufactured by thermally curing a laminate containing a skin layer, a core layer, and an adhesive. The thermal curing may be performed for approximately 5 minutes to 2 hours at a curing temperature of 50 to 110° C. of the epoxy resin, and curing may be performed for approximately 1 to 10 hours at room temperature.

The adhesive layer may be applied to a thickness of approximately 20 to 300 μm, but is not limited thereto.

As a method of applying the adhesive layer to one surface of the skin layer 20, any one selected from a die coating method, a gravure coating method, a knife coating method, or a spray coating method may be used.

Another adhesive used for the adhesive layer may include a first adhesive layer including high-density polyethylene (HDPE) and a second adhesive layer including low-density polyethylene (LDPE).

The high density polyethylene (HDPE) may have a density of 0.940 to 0.965 g/cm ³ , and the low density polyethylene (LDPE) may be 0.910 to 0.925 g/cm ³ .

The adhesive constituting the adhesive layer is not particularly limited as long as it can form a first adhesive layer containing high-density polyethylene (HDPE) and a second adhesive layer containing low-density polyethylene (LDPE), but is preferably coextruded using a film extruder. And manufactured.

The adhesive layer may be applied to a thickness of approximately 20 to 300 μm, and the first adhesive layer and the second adhesive layer may each have a thickness of 10 to 150 μm, but are not limited thereto, and the first adhesive layer and the second adhesive layer The thickness of the adhesive layer may be the same or different.

In order to form a skin layer on the adhesive layer, a sandwich panel may be manufactured by placing the skin layer on the adhesive layer and then thermocompressing a laminate including the skin layer, the core layer, and the adhesive. The thermocompression may be performed at 150 to 200°C for about 3 to 10 minutes at a pressure of 2 to 10 MPa.

At this time, the core layer is placed so that the high-density polyethylene (HDPE) adhesive is attached, and the skin layer and the low-density polyethylene (LDPE) adhesive are attached. In this way, LDPE adhesive is used for the skin layer so that it can be easily adhered even with relatively low heat.In the case of the core layer, HDPE adhesive is used to prevent all the adhesive melted by heat from penetrating into the core and not exhibiting adhesive strength. By doing so, it is possible to improve the adhesion between the respective components.

Sandwich panel manufacturing method

The sandwich panel according to the present invention is formed by sequentially stacking the skin layer 20, the core layer 10, and the skin layer 20, and an adhesive layer is applied between the core layer 10 and the skin layer 20. It is manufactured by After the above components are stacked, the curing and pressing steps may be performed, but the present invention is not limited thereto.

Specifically, the method of manufacturing a sandwich panel according to the present invention,

a) preparing two or more nonwoven fiber aggregates; b) manufacturing a core layer by bonding the interfaces of the two or more nonwoven fiber aggregates to each other through a flame lamination process; c) forming an adhesive layer on at least one surface of the core layer; And d) forming a skin layer on the adhesive layer.

The core layer 10 of the sandwich panel according to the present invention is composed of the molded body according to the present invention as discussed above. Therefore, the steps a) and b) are the same as the method of manufacturing the molded article described above.

Thereafter, in step c), an adhesive layer is formed on at least one surface of the core layer.

The adhesive constituting the adhesive layer may include at least one of an olefin-based adhesive, a urethane-based adhesive, an acrylic adhesive, and an epoxy-based adhesive. As the olefin-based adhesive, at least one selected from the group consisting of polyethylene, polypropylene, and amorphous polyalphaolefin adhesive may be used. The urethane-based adhesive may be used without limitation as long as it includes a urethane structure (-NH-CO-O-). The acrylic adhesive may include at least one of a polymethyl methacrylate adhesive, a hydroxy group-containing polyacrylate adhesive, and a carboxy group-containing polyacrylate adhesive. The epoxy adhesive includes at least one of bisphenol-A type epoxy adhesive, bisphenol-F type epoxy adhesive, novolac epoxy adhesive, linear aliphatic epoxy resins, and cycloaliphatic epoxy resins. Can include.

In addition, the adhesive may include a photocurable adhesive, a hot melt adhesive, or a thermosetting adhesive, and any one of a photocuring method and a thermosetting method may be used. For example, a sandwich panel can be manufactured by thermally curing a laminate containing a skin layer, a core layer, and an adhesive. The thermal curing may be performed for approximately 5 minutes to 2 hours at a curing temperature of 50 to 110° C. of the epoxy resin, and curing may be performed for approximately 1 to 10 hours at room temperature.

The adhesive layer may be applied to a thickness of approximately 20 to 300 μm, but is not limited thereto.

As a method of applying the adhesive layer to one surface of the skin layer 20, any one selected from a die coating method, a gravure coating method, a knife coating method, or a spray coating method may be used.

Another adhesive used for the adhesive layer may include a first adhesive layer including high-density polyethylene (HDPE) and a second adhesive layer including low-density polyethylene (LDPE).

The high-density polyethylene (HDPE) may have a density of 0.940 to 0.965 g/cm ³ , and the low-density polyethylene (LDPE) may be 0.910 to 0.925 g/cm ³ .

The adhesive constituting the adhesive layer is not particularly limited as long as it can form a first adhesive layer containing high-density polyethylene (HDPE) and a second adhesive layer containing low-density polyethylene (LDPE), but is preferably coextruded using a film extruder. And manufactured.

The adhesive layer may be formed to have a thickness of approximately 20 to 300 μm, and the first adhesive layer and the second adhesive layer may each have a thickness of 10 to 150 μm, but are not limited thereto, and the first adhesive layer and the second adhesive layer The thickness of the adhesive layer may be the same or different.

Thereafter, in step d), a skin layer is formed on the adhesive layer.

The skin layer 20 of the sandwich panel according to the present invention may be formed of a metal material, preferably aluminum, iron, stainless steel (SUS), magnesium, electrogalvanized steel sheet (EGI), and hot-dip galvanized steel sheet (GI ) It may include any one or more selected from the group consisting of. For example, in order to have excellent formability and flexural stiffness, the skin layer 20 including an electrogalvanized steel sheet (EGI) may be applied to the sandwich panel. In addition, in order to reduce weight, the skin layer 20 including aluminum may be applied to the sandwich panel.

In the step d), a skin layer may be formed by laminating a core layer, an adhesive, and a skin layer, followed by photocuring or thermal curing. In order to form the skin layer on the adhesive layer, any one of a photocuring method, a thermosetting method, and a thermocompression bonding method may be used. For example, a sandwich panel can be manufactured by thermally curing or thermocompressing a laminate containing a skin layer, a core layer, and an adhesive.

The thermal curing may be performed for approximately 5 minutes to 2 hours at a curing temperature of 50 to 110° C. of the epoxy resin, and curing may be performed for approximately 1 to 10 hours at room temperature.

In the case of using an adhesive including a first adhesive layer containing the high-density polyethylene (HDPE) and a second adhesive layer containing the low-density polyethylene (LDPE), the thermal compression bonding is performed after placing the skin layer on the adhesive layer, and then the skin layer, A sandwich panel can be manufactured by thermocompressing a laminate containing a core layer and an adhesive. The thermocompression may be performed at 150 to 200°C for about 3 to 10 minutes at a pressure of 2 to 10 MPa.

At this time, the core layer is placed so that the high-density polyethylene (HDPE) adhesive is attached, and the skin layer and the low-density polyethylene (LDPE) adhesive are attached. In this way, LDPE adhesive is used for the skin layer so that it can be easily adhered even with relatively low heat.In the case of the core layer, HDPE adhesive is used to prevent all the adhesive melted by heat from penetrating into the core and not exhibiting adhesive strength. By doing so, it is possible to improve the adhesion between the respective components.

As described above, the sandwich panel according to the present invention has excellent mechanical strength as well as moldability by using a core layer having good mechanical properties while being lightweight. In addition, the interfacial peeling force is improved by bonding between the interfaces inside the core material for sandwich panels through flame lamination, so that structural materials for home appliances (TV back cover, board for washing machines, etc.), interior and exterior boards for buildings, interior and exterior materials for automobiles, trains/ships/ It is suitable for use as interior and exterior materials for aircraft (boards such as partitions), various partition boards, and elevator structural materials.

Hereinafter, preferred embodiments are presented to aid in the understanding of the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention. It is natural that changes and modifications fall within the scope of the appended claims.

Example: Fabrication of a sandwich panel

Preparation of core layer (molded body): Preparation Examples 1 to 11

[Production Examples 1 to 9]

Polyethylene terephthalate (PET) fiber (Toray Chemical, RPF, fineness 4 denier, fiber length 51㎜) and sheath part, non-hygroscopic resin cis-core PET fiber (Toray Chemical, EZBON-L, fineness 4 denier, sheath After preparing a partial melting point of 164° C., fiber length 64 mm), they were mixed in a weight ratio of 30:70.

The mixed fibers were carded with a roller carding machine and thermally bonded at a temperature of 190° C. for 10 seconds using a heat press to prepare a nonwoven fabric.

One side of the nonwoven fabric is heated with a laminating flame generator (Flame Laminating Machine, World FLY) to make the interface in a molten state, and then the melted interfaces of each of the two nonwoven fabrics are bonded together to form a nonwoven fabric having a basis weight of 3,600 gsm. Was prepared. At this time, the conditions of the flower lamination process are shown in Table 1 below.

	Flame temperature (℃)	Caloric value (kcal)	Gas flow rate (Nm 3 /h)	Air excess rate
Manufacturing Example 1	730	17,004	1.8	1.03
Manufacturing Example 2	745	18,893	2	0.93
Manufacturing Example 3	800	20,782	2.2	One
Manufacturing Example 4	820	26,450	2.8	0.94
Manufacturing Example 5	840	39,495	1.7	0.58
Manufacturing Example 6	860	41,818	1.8	0.67
Manufacturing Example 7	890	42,037	4.45	0.94
Manufacturing Example 8	900	47,232	5	0.84
Manufacturing Example 9	980	68,014	7.2	0.58

Thereafter, the nonwoven fabric was transferred to a double belt press at a speed of 5 m/min. At this time, the heating temperature of the double belt press was 180°C and the pressure was 5 MPa, and a core layer having a thickness of 5.7 mm was prepared by heating/pressing treatment for 2 minutes.

[Production Example 10]

After attaching the nonwoven fabric manufactured by thermally bonding the mixed fibers with carding and heating press to two unwinding devices, a needle punching process with ^{500 punching times per minute and 200 punches/cm 2 punching density was repeatedly performed.} Physical re-bonding was formed between the nonwovens. The same method as in Preparation Examples 1 to 9, except that the nonwoven fabric bonded by needle punching was introduced into a preheating chamber at a temperature of 180° C. and then preheated for 3 minutes to prepare a nonwoven fabric having a basis weight of 3,600 gsm. To prepare a core layer.

[Production Example 11]

After forming an adhesive film by applying an adhesive (DI-1030, Samsung Gratech) to one interface of the nonwoven fabric manufactured by thermally bonding the mixed fibers with carding and heating press, it is laminated so that one interface of the other nonwoven fabric adheres to the adhesive film. do. Thereafter, the core layer was prepared in the same manner as in Preparation Examples 1 to 9, except that the nonwoven fabric was introduced into a preheating chamber at a temperature of 180°C and preheated for 3 minutes to prepare a nonwoven fabric having a basis weight of 3,600 gsm. I did.

Manufacture of sandwich panel: Examples 1 to 9 and Comparative Examples 1 to 2

[Example 1]

After applying an epoxy adhesive (Kukdo Chemical) on both sides of the core layer prepared in Preparation Example 1, a skin layer formed of an electro-galvanized steel sheet was formed to a thickness of 0.4 mm, and the laminated product was thermally cured at 100°C. Thus, a sandwich panel was manufactured.

[Examples 2 to 9]

A sandwich panel was manufactured in the same manner as in Example 1, except that the core layers prepared in Preparation Examples 2 to 9 were used according to Table 2 below.

[Comparative Examples 1 to 2]

A sandwich panel was manufactured in the same manner as in Example 1, except that the core layers prepared in Preparation Examples 10 to 11 were used according to Table 2 below.

	Core layer used
Example 1	Manufacturing Example 1
Example 2	Manufacturing Example 2
Example 3	Manufacturing Example 3
Example 4	Manufacturing Example 4
Example 5	Manufacturing Example 5
Example 6	Manufacturing Example 6
Example 7	Manufacturing Example 7
Example 8	Manufacturing Example 8
Example 9	Manufacturing Example 9
Comparative Example 1	Manufacturing Example 10
Comparative Example 2	Manufacturing Example 11

Experimental Example: Measurement of peel strength, process speed, and density of flame lamination joints

(Measurement of peeling strength and process speed)

After fabricating the sandwich panels prepared in Examples 1 to 9 and Comparative Examples 1 to 2 as specimens (25mm x 25mm), the peel strength between the nonwoven fabric layers in the core layer was measured using a universal testing machine (INSTRON) according to ASTM C297. It was measured. The peel strength for each specimen was measured five times, and the average value is shown in Table 3.

	Peel strength (psi)	Process speed (m/min)
Example 1	270.98	5
Example 2	274.72	5
Example 3	284.37	5
Example 4	329.34	5
Example 5	437.28	5
Example 6	463.68	5
Example 7	491.24	5
Example 8	577.12	5
Example 9	360.4	5
Comparative Example 1	443.72	One
Comparative Example 2	145.39	5

Referring to Table 3, it was found that the process speed was improved in Examples 1 to 9 in which the flame lamination process was performed, compared to the case of Comparative Example 1 in which the needle punching process was performed. In addition, Examples 1 to 9 were found to have improved peel strength compared to the case of Comparative Example 2 using an adhesive film. In particular, it was found that Examples 5 to 8 had an excellent peel strength of 400 psi or more with an excellent process speed of 5 m/min.

(Measure the density of the flame lamination junction)

Sandwich panels of Examples 1 to 9 were prepared as specimens (25mm x 25mm). Thereafter, the interface at the place with the thinnest bonding thickness among the bonding portions bonded through flame lamination was removed with a knife, and the thickness and mass were measured to measure the density of the bonding portion, and are shown in Table 4 below.

	Junction density (g/cm 3 )
Example 1	0.43
Example 2	0.43
Example 3	0.43
Example 4	0.53
Example 5	0.61
Example 6	0.61
Example 7	0.65
Example 8	0.76
Example 9	0.53

Referring to Table 4, it was found that as the density of the junction through flame lamination increased, the peel strength between the nonwoven fabric layers in the core layer was improved. In particular, it was found that the junction density was the highest in the flame lamination process conditions of Example 8, and the peel strength between the nonwoven fabric layers was the most excellent.

All simple modifications to changes of the present invention belong to the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

Claims (20)

1. It is a non-woven fiber aggregate structure comprising two or more non-woven fiber aggregates and at least one joint portion in which the non-woven fiber aggregates are bonded to each other,

   ^{The density of the junction (g/cm 3} ) is 2 to 4.5 times the density (g/cm ³ ) of the nonwoven fiber aggregate, a molded article.
2. The method of claim 1,

   The non-woven fiber aggregate structure is a structure in which two or more non-woven fiber aggregates are bonded by heat fusion, a molded article.
3. The method of claim 1,

   The non-woven fiber assembly is a web (Web) or sheet (Sheet) of the non-woven fiber is bonded with an adhesive or by using a thermoplastic fiber, a molded article.
4. The method of claim 1,

   The interfacial peel strength of the junction is 250 to 600 psi, a molded article.
5. The method of claim 1,

   The density of the junction is 0.3 to 0.9 g / cm ³ , the molded article.
6. The method of claim 1,

   The nonwoven fiber aggregate, a molded article comprising a polyester-based fiber.
7. The method of claim 6,

   The polyester fiber is any one or more selected from the group consisting of polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
8. Core layer;

   A skin layer laminated on one or more surfaces of the core layer; And

   Including an adhesive layer for bonding the core layer and the skin layer,

   The core layer is a sandwich panel using the molded article of claim 1.
9. The method of claim 8,

   The skin layer is any one or more selected from the group consisting of aluminum, iron, stainless steel (SUS), magnesium, and electro-galvanized steel sheet (EGI).
10. The method of claim 8,

    The adhesive layer includes at least one of an olefin-based adhesive, a urethane-based adhesive, an acrylic-based adhesive, and an epoxy-based adhesive.
11. The method of claim 8,

    The adhesive layer comprises a first adhesive layer comprising high-density polyethylene (HDPE) and a second adhesive layer comprising low-density polyethylene (LDPE), a sandwich panel.
12. a) preparing two or more nonwoven fiber aggregates; And

    b) bonding the interfaces of the two or more nonwoven fiber aggregates to each other through a flame lamination process.
13. The method of claim 12,

    The step b) is a step of bonding the interface of the nonwoven fiber aggregate through a flame lamination process having a flame temperature of 700 to 1000° C. and a calorific value of 15,000 to 70,000 kcal.
14. The method of claim 12,

    In the step b), the interfacial peel strength of the bonding portion of the nonwoven fiber aggregate to be bonded through the flame lamination process is 250 to 600 psi, the method of manufacturing a molded article.
15. The method of claim 12,

    In the step b), the density of the junction of the nonwoven fiber aggregate to be bonded through the flame lamination process is 0.3 to 0.9 g/cm ³ , the method of manufacturing a molded article.
16. a) preparing two or more nonwoven fiber aggregates;

    b) manufacturing a core layer by bonding the interfaces of the two or more nonwoven fiber aggregates to each other through a flame lamination process;

    c) forming an adhesive layer on at least one surface of the core layer; And

    d) A method of manufacturing a sandwich panel comprising the step of forming a skin layer on the adhesive layer.
17. The method of claim 16,

    In the step d), the core layer, the adhesive and the skin layer are laminated, and then photocured or thermally cured to form a skin layer.
18. The method of claim 17,

    The thermal curing is performed at 50 to 110° C. for 5 minutes to 2 hours, a method of manufacturing a sandwich panel.
19. The method of claim 17,

    The thermal curing is performed at room temperature for 1 to 10 hours, a method of manufacturing a sandwich panel.
20. The method of claim 16,

    The adhesive layer includes a first adhesive layer including high-density polyethylene (HDPE) and a second adhesive layer including low-density polyethylene (LDPE),

    The core layer is bonded to the first adhesive layer, and the skin layer is bonded to the second adhesive layer.

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