JP2022533925A - Masterbatch composition and method for producing foamed sheet using same - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a masterbatch composition that can be used for extrusion and foaming of polyester resin, and a method for producing a foamed polyester resin sheet using the masterbatch composition. Specifically, the masterbatch composition contains a carrier resin and 1 to 30% by weight of a polyfunctional compound, and the carrier resin is 70 to 99% by weight of a polyester resin having a melting point of 200° C. or less, or a melting point of It may contain 55-85% by weight polyester resin above 200° C. and 10-40% by weight polyolefin resin. [Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a masterbatch composition that can be used for extrusion and foaming of polyester resin, and a method for producing a foamed polyester resin sheet using the masterbatch composition.

Polyester resins with crystallinity such as polyethylene terephthalate (PET) have excellent mechanical properties compared to polyethylene resins and polypropylene resins, and are excellent in heat resistance and chemical resistance. It can be used in various fields where high physical properties are required. Due to their excellent mechanical and chemical properties, polyester resins are traditionally used in many applications such as drinking water containers and medical applications, food wrappers, food containers, sheets, It is applied in fields such as films and automobile moldings.

In particular, a foamed sheet containing a polyester resin is excellent in lightness and strength due to having a foamed layer composed of a resin composition containing a polyester resin. Instead, it can be molded into a molded article having a three-dimensional shape, such as by thermoforming.

When polymer resin is continuously molded by extrusion foaming, it is important to control the viscosity of the melted resin. There is a problem that the viscosity must be controlled by mixing the In addition, the cross-linking agent added for extrusion and foaming of the polyester resin includes dianhydrides such as pyromellitic dianhydride. There is a problem that it sticks to the screw or barrel and does not react, and it is thermally decomposed and the thickening effect cannot be obtained.

In order to improve such problems, Patent Document 1 discloses a technique of producing a cross-linking agent in a masterbatch and adding it. However, the addition of a large amount of low-melting-point polyethylene (PE) contained as the base resin of the masterbatch causes non-uniform mixing with the polyester resin, thereby deteriorating the physical properties of the foamed molded product produced. There is a limit to how low it can go. In addition, since the low-melting-point polyethylene, which is the carrier resin of the masterbatch, is not compatible with the polyester resin, which is the foaming resin, low-melting-point polyethylene contaminants are generated on the die and mandrel during extrusion foaming. This causes the inconvenience of requiring periodic cleaning of the foaming device.

European Registered Patent No. 2009043

In order to solve the problems of the prior art as described above, the present invention provides a masterbatch composition with improved compatibility of additives and uniformity of mixing with a foamed resin, and by using the masterbatch composition, an expansion ratio and An object of the present invention is to provide a method for producing a foamed sheet having excellent physical properties.

A masterbatch composition according to an embodiment of the present invention may comprise a carrier resin comprising 70-99 wt% of a polyester resin having a melting point of 200°C or less and 1-30 wt% of a multifunctional compound.

At this time, the polyfunctional compound may have a structure dispersed in the polyester resin matrix as domains.

In another example, a carrier resin comprising 55-85% by weight of a polyester resin having a melting point above 200° C. and 10-40% by weight of a polyolefin resin and 1-30% by weight of a polyfunctional compound may be included.

At this time, the polyolefin resin may be linear low density polyethylene (LLDPE).

On the other hand, the polyester resin may be polyethylene terephthalate (PET).

The above-mentioned polyethylene terephthalate is a polymer of an acid component containing terephthalic acid and isophthalic acid and a diol component containing at least one of ethylene glycol and diethylene glycol. It may be up to 30 mol %.

Also, the average particle size of the polyester resin may be 600-2000 μm, and the average particle size of 70% or more of the polyester resin may be 800-2000 μm.

The polyfunctional compounds include pyromellitic dianhydride, benzophenone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 3,3′,4,4′-biphenyl tetra Carboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) thioether dianhydride, bisphenol A bisether dianhydride, 2,2-bis ( 3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 2,3,6,7-naphthalene-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,2 ,5,6-naphthalene-tetracarboxylic dianhydride, 2,2′,3,3′-biphenyltetracarboxylic dianhydride, hydroquinone bisether dianhydride, bis(3,4-dicarboxyphenyl) sulfoxide It may be one or more selected from the group consisting of dianhydrides and 3,4,9,10-perylenetetracarboxylic dianhydrides.

In addition, the masterbatch composition may further contain a heat stabilizer.

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

In one example, the above foamed sheet manufacturing method includes a masterbatch composition containing 70 to 99% by weight of a polyester resin having a melting point of 200° C. or less and 1 to 30% by weight of a polyfunctional compound, and a The method may include mixing a certain polyester resin with inorganic particles containing an alkaline earth metal carbonate to produce a resin melt, and extruding and foaming the resin melt with an extruder.

In another example, the method for producing a foamed sheet includes a masterbatch composition containing 55 to 85% by weight of a polyester resin having a melting point of over 200°C, 10 to 40% by weight of a polyolefin resin, and 1 to 30% by weight of a polyfunctional compound. and a step of mixing a polyester resin having a melting point of 200 to 270 ° C. and inorganic particles containing an alkaline earth metal carbonate to produce a resin melt, and extruding and foaming the resin melt with an extruder. May include steps.

The resin melt may contain 1 to 30% by weight of the masterbatch composition, 50 to 95% by weight of the polyester resin having a melting point of 200 to 270° C., and 1 to 30% by weight of the inorganic particles. good.

Further, the alkaline earth metal element of the alkaline earth metal carbonate is one or more selected from the group consisting of Ca, Mg and Ba, and the average size of the inorganic particles may be 1 to 5 μm. .

On the other hand, the foamed sheet according to one embodiment of the present invention is manufactured by the above manufacturing method, has an average foaming density of 100-600 kg/m ³ according to KS M ISO 845:2012, and an average thickness of 1.0-5. It may be 0 mm.

The masterbatch composition according to the embodiment of the present invention contains a polyester resin as a main component together with a polyfunctional compound, so that it can be uniformly mixed with the polyester foam resin during extrusion and foaming of the polyester resin, and the generation of foreign matter is prevented. can be removed. In addition, it is possible to prevent the thermal decomposition of additives mixed in the resin melt during the extrusion and foaming of the polyester resin. Therefore, there is an advantage that the process stability is excellent and the expansion ratio of the produced foam sheet is excellent.

The present invention is capable of many modifications and may have many forms. As such, specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not limited to the particular disclosed form, but covers all modifications, equivalents or alternatives falling within the spirit and scope of the invention.

In this application, terms such as "including" or "having" specify the presence of any feature, number, step, act, component, part, or combination thereof described in the specification. It should be understood that it does not preclude the presence or addition of one or more other features, figures, steps, acts, components, parts or combinations thereof. Also, although the terms first, second, etc. may be used to describe various components, the components should not be limited by the terms. The terms are only used to distinguish one component from another. For example, a first component may be named as a second component, and similarly a second component may be named as a first component, without departing from the scope of the present invention. . Singular expressions include plural expressions unless the context clearly dictates a different meaning.

Examples of the present invention are described in more detail below.

The main feature of the present invention is to use a polyester resin having a melting point of 200° C. or less as a carrier resin of a masterbatch composition, or to control the content of a polyolefin resin when using a polyester resin having a melting point of over 200° C. and

Specifically, a polyester resin is included as the carrier resin of the masterbatch composition. Since the carrier resin is the same as the foamed resin, it can be uniformly mixed with the foamed resin during extrusion and foaming of the foamed resin, and thermal decomposition of the polyfunctional compound during the extrusion/foaming process can be suppressed.

In addition, when a polyester having a melting point of 200° C. or less is used as a carrier resin without a polyolefin resin, it also provides an advantage of removing polyethylene contaminants generated on a die and a mandrel during extrusion foaming.

A masterbatch composition according to an embodiment of the present invention may include a polyester resin having a melting point of 200° C. or less and a multifunctional compound. At this time, the polyester resin having a melting point of 200° C. or less is a carrier resin and is a component used in mixing and manufacturing to provide compatibility, and the polyfunctional compound improves the viscosity of the foamed resin. It corresponds to a compound. Here, the melting point of the polyester resin may be 200° C. or lower, specifically 180° C. or lower, more specifically 150° C. or lower.

The content of the polyester resin having a melting point of 200° C. or lower may be 70 to 99% by weight, specifically 70 to 95% by weight, based on the total weight of the masterbatch composition. More specifically, it may be 70 to 90% by weight. If the content of the polyester resin is less than 70% by weight, uneven mixing with the foaming resin may occur, thereby degrading the physical properties of the resulting foam. %, the content of the polyfunctional compound added to the masterbatch will decrease, and the effect of increasing the viscosity of the foamed resin will be insignificant.

In a specific example, the polyfunctional compound may have a structure dispersed on a polyester resin matrix as domains. Even if the same kind of material that is compatible with the foamed polyester resin is used as the matrix of the masterbatch composition, if the polyester resin other than the polyfunctional compound is included as the domain, the domain may not be used during the masterbatch manufacturing process. The presence of a certain polyester resin in a dispersed state may impede the dispersibility of the polyfunctional compound. However, by having a structure containing 1 to 30% by weight of a polyfunctional compound as domains dispersed in a matrix containing 70 to 99% by weight of a polyester resin having a melting point of 200° C. or less, the polyfunctional compound is uniformly dispersed. is possible.

A masterbatch composition according to another embodiment of the present invention may comprise a polyester resin, a polyolefin resin, and a polyfunctional compound having a melting point above 200°C. At this time, polyester resins and polyolefin resins having a melting point of more than 200° C. are components used in mixing and commercialization in order to impart compatibility with carrier resins, and polyfunctional compounds are compounds that improve the viscosity of foamed resins. correspond to Here, the melting point of the polyester resin may be above 200°C, specifically 200 to 270°C.

First, the masterbatch composition contains a polyester resin as a carrier resin. Since the carrier resin of the masterbatch composition is the same as the foamed resin, uniform mixing with the foamed resin may occur during extrusion and foaming of the foamed resin.

The content of the polyester resin may be 55-85 wt%, specifically 60-85 wt%, more specifically 70 wt%, based on the total weight of the masterbatch composition. It may be up to 85% by weight. If the content of the polyester resin is less than 55% by weight, it may be unevenly mixed with the foamed resin, thereby deteriorating the physical properties of the resulting foam. If the content exceeds 85% by weight, the content of the polyfunctional compound added to the masterbatch is reduced, and the effect of increasing the viscosity of the foamed resin is negligible.

The masterbatch composition also contains a polyolefin resin as a carrier resin.

The content of the polyolefin resin may be 10-40% by weight, specifically 10-30% by weight, more specifically 10% by weight, based on the total weight of the masterbatch composition. It may be up to 20% by weight. If the content of the polyolefin resin is less than 10% by weight, the processability and moldability of the masterbatch composition may be deteriorated. If the content exceeds 40% by weight, the content of the polyolefin resin, which is different from the foamed resin, increases, causing non-uniform mixing with the foamed resin, thereby deteriorating the physical properties of the foamed product.

Examples of such polyolefin resins include Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), High Density Polyethylene (HDPE) and Polypropylene, PP) may be one or more selected from the group consisting of. For example, the polyolefin resin is linear low density polyethylene.

Polyester resins of the present invention include aromatic or aliphatic polyester resins synthesized from dicarboxylic acid components and glycol components or hydroxycarboxylic acids. Non-limiting examples of polyester resins include Polyethylene Terephthalate (PET), Polybutylene Terephthalate (PBT), Poly Lactic acid (PLA), Polyglycolic acid (PGA), At least one selected from the group consisting of polyethyleneadipate (PEA), polyhydroxylalkanoate (PHA), polytrimethylene terephthalate (PTT) and polyethylene naphthalate (PEN) good.

Specifically, in the present invention, polyethylene terephthalate may be used as the polyester resin. At this time, the polyethylene terephthalate may be a polymer of an acid component containing terephthalic acid and isophthalic acid and a diol component containing one or more of ethylene glycol and diethylene glycol. Also, the content of isophthalic acid may be 10 to 30 mol % with respect to 100 mol % of the acid component.

The intrinsic viscosity (IV) of the polyester resin may be from 0.4 dliter/g to 1.2 dliter/g. Specifically, the intrinsic viscosity is 0.5 d liter/g to 1.1 d liter/g, 0.6 d liter/g to 1.0 d liter/g, 0.7 d liter/g to 1.1 d liter/g, 0 .9dl/g to 1.1dl/g, 0.5dl/g to 0.7dl/g, 0.6dl/g to 0.7dl/g, 0.7dl/g to 0.7dl/g 9dl/g, 0.75dl/g to 0.85dl/g, 0.77dl/g to 0.83dl/g or even 0.6dl/g to 0.8dl/g good.

On the other hand, the average particle size of the polyester resin in the masterbatch composition may be from 600 to 2,000 μm, specifically from 800 to 2,000 μm, more specifically from 1,000 to 2,000 μm. 000 μm. If the average particle size of the polyester resin in the masterbatch composition is less than the above range, especially if it is less than 800 μm, the particle size of the polyester resin is too small, making it easy to handle in the masterbatch manufacturing process. There is a problem that it is not The average particle size of 70% or more polyester resin may be 800 to 2,000 μm, specifically 1,000 to 2,000 μm, more specifically 1,200 to 2,000 μm. .

The masterbatch composition also includes a polyfunctional compound that crosslinks with the foamed resin to improve viscosity.

The content of the polyfunctional compound may be 1 to 30 wt%, specifically 5 to 30 wt%, more specifically, based on the total weight of the masterbatch composition. may be 10 to 30% by weight. If the content of the polyfunctional compound is less than 1% by weight, the effect of improving the viscosity of the foamed resin may be negligible, and if the content exceeds 30% by weight, the processability of the masterbatch composition is deteriorated. can be

Such polyfunctional compounds include pyromellitic dianhydride (PMDA), benzophenone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 3,3 ',4,4'-biphenyltetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)thioether dianhydride, bisphenol A bisether dianhydride anhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 2,3,6,7-naphthalene-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl) ) sulfone dianhydride, 1,2,5,6-naphthalene-tetracarboxylic dianhydride, 2,2′,3,3′-biphenyltetracarboxylic dianhydride, hydroquinone bisether dianhydride, bis ( It may be one or more selected from the group consisting of 3,4-dicarboxyphenyl)sulfoxide dianhydride and 3,4,9,10-perylenetetracarboxylic dianhydride. Specifically, in the present invention, pyromellitic dianhydride may be used as the polyfunctional compound.

At this time, the melting point of the polyfunctional compound may be 270°C or higher, specifically 270°C to 350°C, 270°C to 330°C, 270°C to 310°C, or 270°C to 290°C. may As an example, if the polyfunctional compound is Pyromellitic dianhydride (PMDA), the melting point may be 280±5°C.

Further, the masterbatch composition of the present invention may contain conventionally known additives such as antioxidants, heat stabilizers, fillers, refractory materials, and mold release agents in order to improve the processability and physical properties of the resin. , colorants and other materials. Specifically, in the present invention, a heat stabilizer may be used as an additive.

The thermal stabilizer may be a pentavalent and/or trivalent phosphorus compound, or may contain a phenolic compound having a large chemical structure and steric hindrance. Specifically, pentavalent and/or trivalent phosphorus compounds may include trimethylphosphite, phosphoric acid, phosphorous acid, tris(2,4-di-tert-butylphenyl)phosphite, and the like. Phenolic compounds with large steric hindrance in chemical structure include pentaerythritol-tetrakis 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propion ester (Pentaerythritol tetrakis(3-(3,5- di-tertbutyl-4-hydroxyphenyl)propionate, Irganox 1010), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (1,1,3-tris(2-methyl -4-hydroxy-5-tert-butylphenyl)butane), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propion ester (octadecyl-3-(3,5-di-tert- butyl-4-hydroxyphenyl)propionate), N,N'-hexamethylenebis(3,5-tert-butyl-4-hydroxyhydrocinnamamide) (N,N'-hexamethylenebis(3,5-di-t- butyl-4-hydroxyhydrocinnamamide)), ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] (ethylenebis(oxyethylene)bis[3-(5-tert- butyl-4-hydroxy-m-tryl) and N,N'-(hexane-1,6-diyl)bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide (N, One or more of N'-(Hexane-1,6-diyl)bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide) may also be included. may be, but is not limited to, 0.1 to 1% by weight based on the total weight of the masterbatch composition.

In addition, the masterbatch composition may have the form of pellets, granules, beads, chips, etc., and in some cases, the form of powder. may Also, the average size is not particularly limited, but in the case of pellet form, the length of the pellet may be 3-6 mm for the uniformity of the cells formed in the foam.

Meanwhile, a method for producing a masterbatch composition according to one embodiment includes pulverizing a polyester resin having a melting point of 200° C. or lower, and extruding the pulverized polyester resin and the polyfunctional compound using an extruder to pelletize them. and may include

A method for producing a masterbatch composition according to another embodiment includes pulverizing a polyester resin having a melting point of more than 200° C., extruding the pulverized polyester resin, polyolefin resin and polyfunctional compound using an extruder to pelletize. and .

Specific descriptions of the polyester resin, the polyolefin resin, and the polyfunctional compound are as described above, and duplicate descriptions are omitted.

The step of pulverizing the polyester resin may be a step of pulverizing the polyester resin to an average particle size of 600 to 2,000 μm. At this time, 70% or more of the polyester resin may have an average particle size of 800 to 2,000 μm.

In the pelletizing step, the temperature of the pelletizing process may be 200°C or less, specifically 180-190°C.

Specifically, when pulverizing a polyester resin having a melting point of 200° C. or less, the temperature in the pelletizing process is lower than the melting point of the multifunctional compound that is the domain of the masterbatch composition, and the melting point of the polyester resin that is the matrix. higher temperature. Thus, the polyfunctional compound, which is the domain in the pelletized masterbatch, may be uniformly dispersed in the polyester resin, which is the matrix. In addition, the polyfunctional compound is not melted during the pelletization process, which prevents the reaction between the polyester resin and the polyfunctional compound, thereby preventing the polyfunctional compound from being thermally decomposed. obtain.

On the other hand, when a polyester resin having a melting point of more than 200° C. is pulverized and pelletized by further containing a polyolefin resin, the temperature in the pelletizing process is lower than the melting points of the polyester resin and the polyfunctional compound in the masterbatch composition, and the polyolefin The temperature is higher than the melting point of the resin. Thus, the polyester resin in the pelletized masterbatch can maintain the average particle size during the grinding step described above. In addition, the polyester resin and the polyfunctional compound are not melted during the pelletization process, thereby preventing the reaction between the polyester resin and the polyfunctional compound. Therefore, the thermal decomposition of the polyfunctional compound can be prevented.

As a result, it is possible to prevent thermal decomposition of additives mixed in the resin melt during extrusion and foaming of the polyester resin. Therefore, there is an advantage that the process stability is excellent and the expansion ratio of the produced foam sheet is excellent.

The present invention also provides a method of producing a foamed sheet using the masterbatch composition described above.

A method for producing a foamed sheet according to one embodiment includes a masterbatch composition containing a polyester resin having a melting point of 200° C. or less and a polyfunctional compound, a polyester resin having a melting point of 200 to 270° C., and an alkaline earth metal carbonate. mixing salt-containing inorganic particles to produce a resin melt; mixing a foaming agent into the resin melt to form a foamable melt; and extruding and foaming the foamable melt. It's okay.

A method for producing a foamed sheet according to another embodiment comprises a masterbatch composition containing a polyester resin with a melting point of over 200° C., a polyolefin resin and a polyfunctional compound, a polyester resin with a melting point of 200 to 270° C., and alkaline earth. mixing inorganic particles containing metal carbonates to produce a resin melt; mixing a blowing agent into the resin melt to form a foamable melt; extruding and foaming the foamable melt; manufacturing the foam sheet.

The step of producing the resin melt may be performed at a temperature of 260-300°C.

The resin melt may also contain 1-30% by weight of the masterbatch composition, 50-95% by weight of a polyester resin having a melting point of 200-270° C., and 1-30% by weight of inorganic particles.

The content of the masterbatch composition may be 1-30% by weight, specifically 1-10% by weight, based on the total weight of the resin melt. At this time, if the content of the masterbatch composition is less than 1% by weight, it is difficult to achieve the desired effect of improving the viscosity of the foamed resin, and if it exceeds 30% by weight, problems such as deterioration of processability may occur. can occur.

The polyester resin may be one or more selected from the group consisting of aromatic and aliphatic polyester resins synthesized from dicarboxylic acid components and glycol components or hydroxycarboxylic acids. Examples of polyester resins are given above. In addition, the polyester resin may be in the form of pellets, granules, beads, chips, etc. In some cases, it may be in the form of powder. .

Since the resin melt contains alkaline earth metal carbonate, the cell size of the foamed sheet can be reduced and the density can be increased, and the surface of the sheet is uniform, so that the occurrence of wrinkles (corrugation) is reduced. It can be made and can exhibit excellent thermoformability. Moreover, the foamed sheet obtained by extruding and foaming the resin with calcium carbonate uniformly distributed in the polyester resin has a high thermal conductivity, and can solve the problem that the foamed sheet is torn during molding.

The alkaline earth metal carbonate may be an inorganic carbonate containing one or more cations selected from the group consisting of Ca, Mg and Ba. Specifically, the inorganic particles containing alkaline earth metal carbonates may include calcium carbonate (CaCO ₃ ), magnesium carbonate (MgCO ₃ ) and barium carbonate (BaCO ₃ ); Inorganic particles of the invention may comprise calcium carbonate.

The inorganic particles may have an average size of 1.0 to 5.0 μm. For example, the inorganic carbonate has an average particle size of 1.0-4.0 μm, 1.0-3.0 μm, 1.0-2.0 μm, 2.0-5.0 μm, or 3.0-5 μm. 0 μm.

Inorganic particles containing an alkaline earth metal carbonate may also be mixed with a polyester resin and a masterbatch composition in the form of a masterbatch to produce a resin melt.

For example, the step of extrusion foaming includes hydrophilizing agents, heat stabilizers, waterproof agents, cell size enlarging agents, infrared attenuating agents, plasticizers, fire retardant chemicals, pigments, elastic polymers, extrusion aids, antioxidants, anti-skid agents. One or more additives selected from the group consisting of agents and UV absorbers may be introduced into the fluid connection line. Additives that are not introduced into the fluid connection line among the additives required during the production of the foamed sheet can be introduced during the extrusion process.

The waterproofing agent is not particularly limited, and examples thereof include silicone-based, epoxy-based, cyanoacrylic acid-based, polyvinyl acrylate-based, ethylene vinyl acetate-based, acrylic acid-based, chloroprene rubber-based, mixture systems of polyurethane resin and polyester resin, Mixtures such as polyol and polyurethane resin mixture systems, acrylic polymer and polyurethane resin mixture systems, polyimide systems and cyanoacrylate and urethane mixture systems may also be included.

Examples of blowing agents include physical blowing agents such as N ₂ , CO ₂ , freon, butane, pentane, neopentane, hexane, isohexane, heptane, isoheptane, methyl chloride, and the like. Butane may be used in the invention.

In addition, the step of extruding and foaming may be performed by cooling the foamable melt at 220° C. to 260° C. so as to facilitate foaming, and then passing the cooled foamable melt through a die. . At this time, the intrinsic viscosity of the foamable melt may be 0.9 dl/g or more and in the range of 1.2 dl/g to 1.5 dl/g. A foam having a high expansion ratio can be effectively produced by controlling the intrinsic viscosity of the resin so as to be suitable for foaming. Also, the formed foam sheet can maintain its shape using a calibrator.

The average foam density according to KS M ISO 845:2012 of the produced foam sheets is 100-600 kg/m 3 , 100-500 kg/m ³ , 100-400 kg/m ³ , 100-300 kg/m ³ , 100-200 kg/m ³ . m ³ , 200-600 kg/m ³ , 300-600 kg/m ³ , 400-600 kg/m ³ , or 500-600 kg/m ³ .

Also, the average thickness of the foam sheet may be in the range of 1.0 to 5.0 mm. For example, the average thickness of the foam sheet is 1.0 to 4.0 mm, 1.0 to 3.5 mm, 1.0 to 3.0 mm, 1.0 to 5.5 mm, 1.0 to 2.0 mm. , 1.0-1.5 mm, 1.5-5.0 mm, 2.0-5.0 mm, 3.0-5.0 mm, or 4.0-5.0 mm.

Hereinafter, the present invention will be described in detail with reference to examples as follows. However, the following examples are merely illustrative of the present invention, and the present invention is not limited by the following examples.

[Production Example 1]
Polyethylene terephthalate (PET) having a melting point of 180° C. was dried at 130° C. to remove moisture and pulverized to an average particle size of 600-2,000 μm. At this time, 70% or more of the pulverized PET had an average particle size of 800 to 2,000 μm. Then, 89.9% by weight of pulverized PET, 10% by weight of pyromellitic dianhydride (PMDA) and 0.1% by weight of heat stabilizer (Irganox 1010) are mixed to prepare a composition, and the prepared composition The material was pelletized at 185° C. using an extruder to produce a masterbatch.

[Production Examples 2 and 3]
Each masterbatch was prepared through the same process as Preparation Example 1, except that the melting point of PET was adjusted as shown in Table 1 below.

[Production Example 4]
Polyethylene terephthalate (PET) with a melting point of 250° C. was dried at 130° C. to remove moisture and pulverized to an average particle size of 600-2,000 μm. At this time, the average particle size of 70% or more pulverized PET was 800 to 2,000 μm. Then 60 wt% milled PET, 29.9 wt% linear low density polyethylene (LLDPE), 10 wt% pyromellitic dianhydride (PMDA) and 0.1 wt% heat stabilizer (Irganox 1010) are mixed. The resulting composition was pelletized at 185° C. using an extruder to produce a masterbatch.

[Production Examples 5 and 6 and Comparative Production Example 1]
Masterbatches were prepared in the same manner as in Preparation Example 4, except that the contents of PET and LLDPE were adjusted as shown in Table 1 below.

[Comparative Production Example 2]
Instead of the pulverized PET used in Preparation Example 4, pulverized PET with an average particle size of 100-300 μm and 80% or more of the pulverized PET with an average particle size of 100-200 μm was used. Thereafter, masterbatches were prepared in the same manner as in Preparation Example 4, except that the contents of PET and LLDPE were adjusted as shown in Table 1 below.

[Example 1]
In order to manufacture a polyester foam sheet, first, 100 parts by weight of polyethylene terephthalate (PET) resin was dried at 180° C. to remove moisture, and 92.5% by weight of the moisture-removed PET resin was extruded. 4.5% by weight of the masterbatch composition prepared in A. and 3% by weight of calcium carbonate having an average particle size of 1.0 to 5.0 μm were mixed and heated at 280° C. to prepare a resin melt. Thereafter, 1.5 parts by weight of butane as a foaming agent was introduced into the extruder 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 passed through a die and extruded to produce a PET foam sheet with an average thickness of 2.0 mm. At this time, the density of the produced PET foam sheet was 350 kg/m ³ .

[Examples 2 to 6]
Each foam sheet was prepared in the same manner as in Example 1, except that the masterbatch compositions prepared in Preparation Examples 2 to 6 were used instead of the masterbatch composition prepared in Preparation Example 1. .

[Comparative Examples 1 and 2]
Foamed sheets were prepared in the same manner as in Example 1, except that the masterbatch compositions prepared in Comparative Preparation Examples 1 and 2 were used instead of the masterbatch composition prepared in Preparation Example 1. did.

[Experimental example]
The physical properties of the foamed sheets produced in Examples 1 to 6 and Comparative Examples 1 and 2 and processability during production were evaluated. Specifically, the physical properties and processability were measured as follows, and the results are shown in Table 2 below.

1) Intrinsic viscosity (IV) measurement A foamed sheet was dissolved in a mixed solution of phenol/tetrachloroethane (mixing ratio: 50%/50% by weight) to prepare a solution with a concentration of 0.5% by weight, and then measured with an Ubbelohde viscometer. was used to measure the viscosity of the solution at 35°C.

2) Measurement of average thickness and expansion ratio of foam sheet (density measurement)
In order to measure the average thickness of each foam sheet, the entire width of each foam sheet was divided into 8 parts at regular intervals, the thickness was measured using an indicator (ID-C112, MItutoyo), and the average value was calculated. .

In order to measure the average foam density of each foam sheet, a 2 cm wide×2 cm long sample was taken from each foam sheet, and the foam density was measured with an underwater electronic densitometer (EW300SG, MIRAGE).

3) Evaluation of processability The foaming processability of the foamed sheet was evaluated by randomly selecting a plurality of samples from the produced foamed sheet, measuring the density, and evaluating the uniformity of the measured density. Specifically, 10 samples were randomly selected from 30 minutes after the start of foam sheet production to the end of production, the density was measured in the same manner as described above, and the density average value of the measured 10 samples. The deviation was derived based on

4) Checking the degree of foreign matter generation The degree of foreign matter generation on the die and mandrel of the foaming device was visually confirmed.

As can be seen from Table 2, the masterbatch compositions according to Preparation Examples 1 to 6 contain a polyester resin (PET) as a main component together with a polyfunctional compound (PMDA). It was confirmed that the foamed sheets according to Examples 1 to 6 had higher intrinsic viscosities than those of Comparative Examples 1 and 2 by uniformly mixing with.

Also, the foam sheets according to Examples 1-6 showed a lower density deviation than Comparative Example 1. This is because thermal decomposition of the additives mixed in the resin melt is prevented during extrusion and foaming of the polyester resin, resulting in excellent process stability and an excellent foaming ratio of the produced foam sheet. was confirmed.

On the other hand, in the case of Examples 1 to 3, by using a low melting point polyester resin (PET) compatible with the foaming resin as the matrix of the masterbatch composition, it was found that foreign matter was not generated on the die and mandrel of the foaming device. It could be confirmed.

In addition, in the case of Examples 4 to 6, the masterbatch composition contained polyethylene resin (LLDPE) and polyester resin (PET) as a main component. And it was found that only a small amount of foreign matter was generated on the mandrel.

In addition, in the case of Comparative Example 2, the same level of foaming characteristics as those of the Examples is exhibited, but the average particle size of the polyester resin in the masterbatch is too small, and there is a problem that handling in the masterbatch manufacturing process is not easy. there were.

Having described above with reference to preferred embodiments of the present invention, it will be appreciated by those skilled in the art or those of ordinary skill in the art that the scope of the invention as set forth in the claims that follow. It will be understood that various modifications and alterations may be made to the present invention without departing from the spirit and scope of the invention.

Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be defined by the scope of the claims.

The masterbatch composition according to the embodiment of the present invention contains a polyfunctional compound and a polyester resin as a main component, so that the polyester resin can be uniformly mixed with the polyester foam resin during extrusion and foaming, and foreign matter is generated. can be removed. In addition, it is possible to prevent thermal decomposition of additives mixed in the resin melt during extrusion and foaming of the polyester resin. Therefore, there is an advantage that the process stability is excellent and the expansion ratio of the produced foam sheet is excellent.

Claims (13)

a carrier resin;
1 to 30% by weight of a polyfunctional compound,
And the carrier resin contains 70 to 99% by weight of a polyester resin having a melting point of 200° C. or less, or 55 to 85% by weight of a polyester resin having a melting point of over 200° C. and 10 to 40% by weight of a polyolefin resin. thing. The carrier resin contains 70 to 99% by weight of a polyester resin having a melting point of 200° C. or less,
2. The masterbatch composition according to claim 1, having a structure in which the polyfunctional compound is dispersed as domains in the matrix of the polyester resin. The masterbatch composition of claim 1, wherein the polyester resin is Polyethylene Terephthalate (PET). The polyethylene terephthalate is a polymer of an acid component containing terephthalic acid and isophthalic acid and a diol component containing one or more of ethylene glycol and diethylene glycol,
The masterbatch composition according to claim 3, wherein the content of isophthalic acid is 10-30 mol% with respect to 100 mol% of the acid component. The masterbatch composition according to claim 1, wherein the polyester resin has an average particle size of 600 to 2000 µm. 6. The masterbatch composition of claim 5, wherein the average particle size of 70% or more of the polyester resin is 800-2000 μm. 2. The masterbatch composition of claim 1, wherein the polyolefin resin is Linear Low Density Polyethylene (LLDPE). The polyfunctional compound includes pyromellitic dianhydride, benzophenone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 3,3′,4,4′-biphenyltetra Carboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) thioether dianhydride, bisphenol A bisether dianhydride, 2,2-bis ( 3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 2,3,6,7-naphthalene-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,2 ,5,6-naphthalene-tetracarboxylic dianhydride, 2,2′,3,3′-biphenyltetracarboxylic dianhydride, hydroquinone bisether dianhydride, bis(3,4-dicarboxyphenyl) sulfoxide The masterbatch composition according to claim 1, which is one or more selected from the group consisting of dianhydrides and 3,4,9,10-perylenetetracarboxylic dianhydrides. 2. The masterbatch composition of claim 1, wherein said masterbatch composition further comprises a heat stabilizer. A resin melt is prepared by mixing a masterbatch composition containing a carrier resin and 1 to 30% by weight of a polyfunctional compound, a polyester resin having a melting point of 200 to 270° C., and inorganic particles containing an alkaline earth metal carbonate. and a step of extruding and foaming the resin melt with an extruder,
and the carrier resin contains 70 to 99% by weight of a polyester resin having a melting point of 200° C. or less, or 55 to 85% by weight of a polyester resin having a melting point of over 200° C. and 10 to 40% by weight of a polyolefin resin. . The resin melt according to claim 10, wherein the resin melt contains 1 to 30% by weight of the masterbatch composition, 50 to 95% by weight of the polyester resin having a melting point of 200 to 270°C, and 1 to 30% by weight of the inorganic particles. A method for manufacturing a foam sheet. The alkaline earth metal element of the alkaline earth metal carbonate is one or more selected from the group consisting of Ca, Mg and Ba, and the inorganic particles have an average size of 1 to 5 μm, according to claim 10. of the foam sheet manufacturing method. Manufactured by the manufacturing method according to any one of claims 10 to 12,
A foam sheet having an average foam density according to KS M ISO 845:2012 of 100-600 kg/m ³ and an average thickness of 1.0-5.0 mm.