KR102465632B1 - Polyester resin foam sheet having embossed surface and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a polyester resin foam sheet having a linear patterned surface and a method for manufacturing the same, and provides a foam sheet having a high surface roughness and excellent interfacial bonding properties when laminated with other layers.

Description

Polyester resin foam sheet having a linear patterned surface and its manufacturing method

The present invention relates to a polyester resin foam sheet having a linear patterned surface and a manufacturing method thereof.

Polyester resin has excellent mechanical and chemical properties and is used in various fields such as drinking water containers, medical devices, food packaging, food containers, sheets, films, or automobile molded products. can be utilized For example, a polyester resin having crystallinity such as polyethylene terephthalate (PET) has excellent mechanical properties and excellent heat resistance and chemical resistance compared to polyethylene-based resins or polypropylene-based resins.

In particular, a foam sheet using a polyester resin has excellent light weight and strength, and can be molded into a molded body having a three-dimensional shape through thermoforming or the like. However, the polyester resin foam sheet has disadvantages in that it is difficult to impart a desired shape by thermoforming or the like due to its high rigidity, and it is brittle. In addition, the polyester foam sheet is often applied in the form of being laminated with other layers in a state where an adhesive layer is interposed according to its use. In addition, it is common to undergo a thermoforming process in which heat and pressure are applied to the laminated body. However, in the process of thermoforming the laminated body, a problem arises in that the interface is separated due to air bubbles present at the interface or a decrease in surface adhesion.

Therefore, it is required to develop a polyester foam sheet that has excellent thermoformability and can increase interfacial bonding during molding.

The present invention was invented to solve the above problems, and an object of the present invention is to provide a polyester resin foam sheet having a linear patterned surface and a manufacturing method thereof.

The polyester resin foam sheet according to the present invention relates to a polyester resin foam sheet in which 90% or more of the cells are closed cells (DIN ISO4590).

In one example, one side or both sides of the foam sheet has a structure in which a linear pattern having orientation is formed, and a cross section of the foam sheet on which the linear pattern is formed has a shape in which protrusions and depressions are repeated.

In one example, the cross section of the foam sheet on which the linear pattern is formed has a structure in which protrusions and depressions are repeated 5 to 200 times per unit length (1 cm).

In a specific example, the foam sheet has a structure in which linear patterns are formed on both sides, and the irregularities formed on one side of the foam sheet are repeated 5 to 30 times per unit length (1 cm), and formed on the other side of the foam sheet. The unevenness is a structure that is repeated 40 to 200 times per unit length (1 cm).

In another example, the average cell size of the foam sheet ranges from 80 μm to 500 μm.

In another example, the foam sheet includes inorganic particles containing alkaline earth metal carbonate, and the content of the inorganic particles is in the range of 0.5 to 5% by weight.

In a specific example, the polyester resin is a polyethylene terephthalate resin.

The present invention also provides a method for producing the polyester resin foam sheet described above.

In one example, the manufacturing method of the polyester resin foam sheet, the step of extruding and foaming the polyester resin; and pressing one side or both sides of the extrusion-foamed foam sheet with a roller having a linear pattern structure in an indented form.

In another example, the manufacturing method further includes heating or cooling one or both sides of the foam sheet between the extrusion and foaming and the pressing with the roller.

In a specific example, the step of extruding and foaming the polyester resin is performed through the step of introducing the polyester resin and inorganic particles into an extruder and extruding and foaming to prepare a foam sheet, wherein the inorganic particles are alkaline earth metal carbonate. It is an inorganic particle containing, and the content of the inorganic particle is in the range of 0.5 to 5% by weight.

The polyester resin foam sheet and its manufacturing method according to the present invention can increase surface roughness and improve interfacial bonding when laminated with other layers.

1 and 2 are schematic views showing the surface structure and cross-sectional structure of a polyester resin foam sheet according to an embodiment of the present invention, respectively.
Figure 3 is a schematic diagram showing the surface structure of a polyester resin foam sheet according to another embodiment of the present invention.
Figure 4 is a schematic diagram showing the process of forming the surface structure of each polyester foam resin according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. Prior to this, terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately uses the concept of terms in order to describe his/her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical spirit of the present invention based on the principle that it can be defined in the following way.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, the term "comprises" or "has" is intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

The foam sheet according to the present invention is a polyester resin foam sheet in which 90% or more cells are closed cells (DIN ISO4590). The foam sheet has a structure in which a linear pattern having orientation is formed on one or both sides of the foam sheet, and the cross section of the foam sheet on which the linear pattern is formed has irregularities in which protrusions and depressions are repeated.

The foam sheet according to the present invention has a structure in which a linear pattern having orientation is formed on the surface. When the foam sheet is laminated with another layer, it is common to perform the laminate in a state in which an adhesive layer is formed on the interface. The embossed structure may serve to increase bonding strength with the adhesive layer by increasing the surface roughness of the foam sheet. In addition, by forming the linear pattern structure, when an adhesive layer is formed on the surface of the foam sheet or when another layer is laminated on the formed adhesive layer, bubbles trapped in the interface are easily discharged or removed. can do.

Furthermore, the surface structure on which the linear pattern is formed can also serve as an antifouling layer. When a foreign material contacts the surface of the foam sheet, the linear pattern structure reduces the contact area between the foam sheet and the foreign material, and has an effect of allowing the foreign material to be easily separated.

In one embodiment, the cross section of the foam sheet on which the linear pattern is formed has a shape in which protrusions and depressions are repeated. At this time, the irregularities are repeated 5 to 200 times per unit length (1 cm). Specifically, the structure is repeated 5 to 100 times, 5 to 30 times, 5 to 20 times, 40 to 200 times, 40 to 100 times, 10 to 100 times, or 10 to 70 times per unit length (1 cm).

It is possible to form linear pattern structures corresponding to the rollers on both sides of the foam sheet by pressing both sides of the extruded foam sheet with a roller having a linear pattern structure embedded therein. In this case, by pressing with rollers having different sizes or numbers of linear patterns, linear pattern structures having different characteristics can be formed on both sides of the foam sheet.

In another embodiment, the foam sheet has a structure in which linear patterns are formed on both sides. At this time, by pressing both sides of the extruded foam sheet with rollers having the same or different linear pattern shapes, it is possible to form the same or different structure of patterns formed on both sides of the foam sheet. In one example, the irregularities formed on one surface of the foam sheet are repeated 5 to 30 times per unit length (1 cm), and the irregularities formed on the other surface of the foam sheet are repeated 40 to 200 times per unit length (1 cm). It is a repeating structure. Specifically, the irregularities formed on one side of the foam sheet are repeated 5 to 20 times per unit length (1 cm), and the irregularities formed on the other side of the foam sheet are repeated 40 to 100 times per unit length (1 cm). It is a structure.

In one embodiment, the cross section of the foam sheet on which the linear pattern is formed has a shape in which protrusions and depressions are repeated. A height difference between the protrusion and the depression forming the unevenness may be, for example, in the range of 0.01 to 1 mm, 0.05 to 0.5 mm, 0.05 to 0.1 mm, 0.01 to 0.5 mm, 0.05 to 1 mm, or 0.05 to 0.1 mm. . By controlling the height difference between the protruding portion and the recessed portion forming the irregularities within the above range, the surface roughness of the foam sheet can be appropriately controlled, and adhesive properties or antifouling properties can be improved as necessary.

In another embodiment, the linear pattern is not particularly limited, but may be a straight line, a curved line, or a wavy pattern. Through this, it is possible to easily remove air bubbles present in the interface when the adhesive is applied to the surface of the foam sheet. As another example, surface roughness can be appropriately controlled, and mechanical strength can be supplemented according to the orientation direction of the linear pattern.

In one embodiment, the average cell size of the foam sheet ranges from 80 μm to 500 μm. Specifically, the average cell size of the foam sheet may be 100 μm to 500 μm, 100 μm to 400 μm, or 350 μm to 500 μm, and more specifically, the average cell size of the foam sheet may be 200 μm to 350 μm or 350 μm to may be 500 μm.

In addition, the average thickness of the foam sheet may be in the range of 1.0 to 10.0 mm. For example, the average thickness of the foam sheet is 1 to 5 mm, 1 to 4 mm, 1 to 3.5 mm, 1 to 3 mm, 1 to 5.5 mm, 1 to 2 mm, 1 to 1.5 mm, 1.5 to 5 mm , 2 to 5 mm, 3 to 5 mm, or 4 to 5 mm.

In one embodiment, the foam sheet according to the present invention contains calcium carbonate, which is an inorganic particle containing alkaline earth metal carbonate in an appropriate range. The foam sheet can improve surface uniformity and moldability of the sheet by uniformly mixing and foaming the inorganic particles with the polyester resin.

Specifically, the foam sheet includes 0.5% by weight to 5% by weight of inorganic particles. The content of the inorganic particles ranges from 0.5 wt% to 5 wt%, 1 wt% to 5 wt%, 1.5 wt% to 4.5 wt%, or 2 wt% to 3.5 wt%. More specifically, the calcium carbonate may be added in an amount of 1.0 wt% to 3.0 wt% or 3.0 wt% to 4.5 wt%.

In one embodiment, the alkaline earth metal element is at least one selected from the group consisting of calcium (Ca), magnesium (Mg), and barium (Ba). For example, the inorganic particles are calcium carbonate (CaCO ₃ ), and the calcium carbonate may have an irregular shape.

In a specific example, the average particle diameter of the inorganic particles ranges from 1 to 5 μm. The average particle diameter of the inorganic particles may be, for example, 1 to 4 μm, 1 to 3 μm, 1 to 2 μm, 2 to 5 μm, or 3 to 5 μm.

Thermal conductivity of the inorganic particles may be 1.0 kcal/mh°C to 3.0 kcal/mh°C. Specifically, the thermal conductivity of the inorganic particles is 1.2 kcal / mh ℃ to 2.5 kcal / mh ℃, 1.5 kcal / mh ℃ to 2.2 kcal / mh ℃, 1.8 kcal / mh ℃ to 2.0 kcal / mh ℃, 1.5 kcal / mh ℃ to 2.5 kcal/mh°C or 1.8 kcal/mh°C to 2.3 kcal/mh°C. As described above, the foam sheet containing the inorganic particles exhibits excellent thermal conductivity, has a uniform surface, and exhibits excellent thermoformability.

Intrinsic Viscosity (IV) of the polyester resin may be 0.4 dl/g to 1.2 dl/g. Specifically, the intrinsic viscosity is 0.5 dl/g to 1.1 dl/g, 0.6 dl/g to 1.0 dl/g, 0.7 dl/g to 1.1 dl/g, 0.9 dl/g to 1.1 dl/g, 0.5 dl/g to 0.5 dl/g. 0.7 dl/g, 0.6 dl/g to 0.7 dl/g, 0.7 dl/g to 0.9 dl/g, 0.75 dl/g to 0.85 dl/g, 0.77 dl/g to 0.83 dl/g or 0.6 dl/g to It may be 0.8 dl/g.

The polyester resin according to the present invention may be at least one selected from the group consisting of aromatic and aliphatic polyester resins synthesized from a dicarboxylic acid component and a glycol component or hydroxycarboxylic acid. The polyester resin may be, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), poly lactic acid (PLA), polyglycolic acid (PGA) , polyethylene adipate (PEA), polyhydroxyalkanoate (Polyhydroxyalkanoate, PHA), polytrimethylene terephthalate (Polytrimethylene Terephthalate, PTT) and polyethylene naphthalene (Polyethylene naphthalate, PEN) may be at least one selected from the group consisting of have. Specifically, polyethylene terephthalate (PET) may be used as the polyester resin according to the present invention.

In addition, the present invention provides a method for producing the polyester resin foam described above. In one embodiment, the manufacturing method includes extruding and foaming a polyester resin; and pressing one side or both sides of the extrusion-foamed foam sheet with a roller having a linear pattern structure in an indented form. Specifically, one or both sides of the extruded foam sheet are pressed with a roller before the foam sheet is completely cooled. The surface of the roller has a structure in which a linear pattern is formed. By pressing with the roller, the thickness of the foam sheet can be reduced by about 5 to 20%, and a linear pattern structure is formed on the surface of the foam sheet to correspond to the indented linear pattern structure formed on the surface of the roller.

In another embodiment, a step of heating or cooling one or both sides of the foam sheet may be further included between the extrusion and foaming and the pressing with the roller. By heating or cooling the extruded foam sheet, physical properties of the foam sheet can be controlled or improved. For example, when the surface of the foam sheet is cooled, the cell size on the surface side decreases and the density increases. It is possible to control the surface properties of the foam sheet according to the required physical properties and at the same time form a concave-convex structure on the surface.

In one embodiment, in the above-mentioned method for producing a foam sheet, the step of extruding and foaming the polyester resin is through the step of introducing the polyester resin and inorganic particles into an extruder and extruding and foaming to prepare a foam sheet. carry out Specifically, the inorganic particles are inorganic particles containing alkaline earth metal carbonate, and the content of the inorganic particles is in the range of 0.5 to 5% by weight. Details on the type and content of the inorganic particles are omitted because they overlap with those described above.

In one example, in the step of introducing the polyester resin into the extruder, the polyester resin may have the form of pellets, granules, beads, chips, etc., and in some cases It can be introduced into the extruder in powder form.

The polyester resin may be at least one selected from the group consisting of aromatic and aliphatic polyester resins synthesized from a dicarboxylic acid component and a glycol component or hydroxycarboxylic acid. Examples of the polyester resin are as described above.

In the method for producing a foam sheet according to the present invention, a foam sheet may be prepared by introducing the polyester resin and calcium carbonate introduced into an extruder into an extruder, melting them, and extruding and foaming them. Specifically, a mixture of polyester resin chips and calcium carbonate may be melted and extruded and foamed. For example, the process of melting the polyester resin and calcium carbonate may be performed at a temperature of 260 °C to 300 °C.

In one example, the step of extruding and foaming the resin can be performed using various types of extruders. In extrusion foaming, by continuously extruding and foaming a resin melt, process steps can be simplified and mass production is possible.

In one example, in the step of preparing the foam sheet according to the present invention, various types of additives may be introduced. The additives may be added during the fluid connection line or during the foaming process, if necessary. Examples of additives may have barrier performance, hydrophilic function or waterproof function, thickeners, surfactants, hydrophilic agents, heat stabilizers, waterproofing agents, cell size expanders, infrared attenuators, plasticizers, fire retardant chemicals, It may include at least one functional additive selected from the group consisting of a pigment, an elastic polymer, an extrusion aid, an antioxidant, a nucleating agent, an antistatic agent, and a UV absorber. Specifically, the foam sheet manufacturing method of the present invention may add one or more of a thickener, a nucleating agent, a heat stabilizer, and a foaming agent, and may further include one or more of the functional additives listed above.

For example, the step of preparing the foam sheet of the present invention includes a thickener, a hydrophilic agent, a heat stabilizer, a waterproofing agent, a cell size expander, an infrared attenuator, a plasticizer, a fire retardant chemical, a pigment, an elastic polymer, an extrusion aid, an antioxidant, One or more additives selected from the group consisting of antistatic agents and UV absorbers may be introduced into the fluid connection line. Among the additives required for manufacturing the foam sheet, additives not introduced in the fluid connection line can be added during the extrusion process.

The thickener is not particularly limited, but in the present invention, for example, pyromellitic dianhydride (PMDA) may be used.

The thermal stabilizer may be an organic or inorganic phosphorus compound. The organic or inorganic phosphorus compound may be, for example, phosphoric acid and its organic ester, phosphorous acid and its organic ester. For example, the heat stabilizer is a commercially available material and may be phosphoric acid, an alkyl phosphate or an aryl phosphate. Specifically, in the present invention, the thermal stabilizer may be triphenyl phosphate, but is not limited thereto, and any material capable of improving the thermal stability of the resin foam sheet may be used without limitation within a typical range.

Examples of the blowing agent include N ₂ , CO ₂ , Freon, butane, pentane, neopentane, hexane, isohexane, heptane, isoheptane, or a physical blowing agent such as methyl chloride. Specifically, butane is used in the present invention. can

In addition, the waterproofing agent is not particularly limited, for example, silicone-based, epoxy-based, cyanoacrylic acid-based, polyvinyl acrylate-based, ethylene vinyl acetate-based, acrylate-based, polychloroprene-based, polyurethane resin and polyester resin It may include mixtures such as a mixture series of polyol and polyurethane resin, a mixture series of acrylic polymer and polyurethane resin, a polyimide series, and a mixture series of cyanoacrylate and urethane.

Hereinafter, the present invention will be described in more detail by examples and experimental examples. However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following Examples and Experimental Examples.

Example 1

In order to prepare a polyester foam sheet, first, 100 parts by weight of a polyethylene terephthalate (PET) resin having a melting point of 245 ° C. was dried at 180 ° C. to remove moisture, and based on 100 parts by weight of the PET resin from which moisture was removed in an extruder, fatigue 5 parts by weight of mellitic acid dianhydride (PMDA), 0.1 part by weight of a heat stabilizer (Iganox 1010), and 3 parts by weight of calcium carbonate having an average particle size of 1.0 to 5.0 μm were mixed and heated to 280° C. to prepare a resin melt.

Thereafter, 1.5 parts by weight of butane was introduced into the extruder as a foaming agent based on 100 parts by weight of the PET resin, and the resin melt was cooled to 250 ± 2 °C. The cooled resin melt was extruded and foamed while passing through a die, and a PET foam sheet having an average thickness of 2.0 mm was prepared.

The prepared foam sheet was pressed with a roller having a wavy pattern to form a pattern corresponding to the pattern of the roller on the surface of the foam sheet.

1 shows the surface structure of a foam sheet specimen 100 according to this embodiment. In the foam sheet specimen 100 shown in FIG. 1, a linear pattern 120 is formed on the surface of the foam sheet 110. The foam sheet specimen 100 has a size of 1 cm in width and length, respectively, and has a shape in which about 13 linear structures are formed per unit length (1 cm).

Figure 2 shows the cross-sectional structure of the prepared foam sheet specimen. Referring to Figure 2, it can be seen that a plurality of irregularities are repeatedly formed on one surface of the foam sheet.

Example 2

A foam sheet was prepared in the same manner as in Example 1, but the embedded pattern structure formed on the roller pressing the surface of the prepared foam sheet was formed differently.

Figure 3 shows the surface structure of the foam sheet specimen 200 according to this embodiment. In the foam sheet specimen 200 shown in FIG. 2, a linear pattern 220 is formed on the surface of the foam sheet 210. The foam sheet specimen 100 has a width and length of 1 cm each, and about 50 linear structures are formed per unit length (1 cm).

Example 3

A foam sheet was prepared in the same manner as in Example 1, but both surfaces of the prepared foam sheet were pressed with a roller.

Figure 4 shows a process for manufacturing a foam sheet according to this embodiment. Referring to FIG. 4, a foam sheet 301, which is an extruded foam sheet and does not have a linear pattern, is supplied from left to right. The foam sheet 301 is pressed while passing between two rollers 410 and 420 that press up and down. On the surface of the two rollers 410 and 420, a linear structure embedded therein is patterned. The foam sheet 301 without a linear pattern becomes a foam sheet 302 with a linear pattern while passing between the two rollers 410 and 420 . In this process, the average thickness of the foam sheet was reduced by about 10%.

In the above, the present invention has been described in more detail through drawings and examples. However, since the configurations described in the drawings or embodiments described in this specification are only one embodiment of the present invention and do not represent all of the technical spirit of the present invention, various equivalents and It should be understood that variations may exist.

100, 200: foam sheet specimen
110, 210: foam sheet
120, 220: linear pattern
301: foam sheet with no linear pattern formed
302: foam sheet formed with a linear pattern
410, 420: roller

Claims (6)

A polyester resin foam sheet in which more than 90% of the cells are closed cells (DIN ISO4590),
The polyester resin is a polyethylene terephthalate resin,
The polyester resin has an intrinsic viscosity (IV) of 0.4 dl/g to 1.2 dl/g,
A structure in which linear patterns having orientation are formed on both sides of the foam sheet,
The cross section of the foam sheet on which the linear pattern is formed is in the form of irregularities in which protrusions and depressions are repeated,
The unevenness formed on one side of the foam sheet has a structure repeated 5 to 30 times per unit length (1 cm),
The unevenness formed on the other side of the foam sheet has a structure that is repeated 40 to 200 times per unit length (1 cm),
The height difference between the protrusion and the depression forming the unevenness is 0.05 to 0.1 mm,
The average cell size of the foam sheet is 80 μm to 500 μm,
The foam sheet includes inorganic particles containing alkaline earth metal carbonate,
The content of the inorganic particles is 0.5 to 5% by weight, and the thermal conductivity is 1.0 to 3.0 kcal / mh ℃ polyester resin foam sheet.
delete delete extruding and foaming a polyester resin; and
Including the step of pressing both sides of the extruded foam sheet with a roller on which a linear pattern structure of an indented form is formed,
The polyester resin is a polyethylene terephthalate resin,
The polyester resin has an intrinsic viscosity (IV) of 0.4 dl/g to 1.2 dl/g,
The unevenness formed on one side of the foam sheet has a structure repeated 5 to 30 times per unit length (1 cm),
The unevenness formed on the other side of the foam sheet has a structure that is repeated 40 to 200 times per unit length (1 cm),
The height difference between the protrusion and the depression forming the unevenness is 0.05 to 0.1 mm,
The average cell size of the foam sheet is 80 μm to 500 μm,
The foam sheet includes inorganic particles containing alkaline earth metal carbonate,
The content of the inorganic particles is 0.5 to 5% by weight, and the thermal conductivity is 1.0 to 3.0 kcal / mh ℃ manufacturing method of the polyester resin foam sheet.
According to claim 4,
Between the extrusion foaming step and the pressing step with the roller,
A method for producing a polyester resin foam sheet, further comprising the step of heating or cooling one side or both sides of the foam sheet.
According to claim 4,
The step of extruding and foaming the polyester resin,
A method for producing a polyester resin foam sheet, which is performed by introducing a polyester resin and inorganic particles into an extruder and extruding and foaming to prepare a foam sheet.

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