KR102339308B1 - Masterbatch composition and manufacturing method of foam sheet using the same - Google Patents

Abstract

The present invention relates to a masterbatch composition usable for extrusion and foaming of a polyester resin, and a method for manufacturing a polyester resin foam sheet using the same. Specifically, the masterbatch composition comprises 55 to 85% by weight of a polyester resin; 10-40 wt% of polyolefin resin; and 1 to 30% by weight of the polyfunctional compound.

Description

MASTERBATCH COMPOSITION AND MANUFACTURING METHOD OF FOAM SHEET USING THE SAME

The present invention relates to a masterbatch composition usable for extrusion and foaming of a polyester resin, and a method for manufacturing a polyester resin foam sheet using the same.

Polyester resins with crystallinity such as polyethylene terephthalate (PET) have superior mechanical properties compared to polyethylene-based resins or polypropylene-based resins, and have excellent heat resistance and chemical resistance, and are used in various fields requiring light weight and high physical properties. This is possible. Polyester resin has excellent mechanical and chemical properties, so it can be used for multi-purpose applications, for example, conventionally for drinking water containers and medical, food packaging, food containers, sheets, films, automobile molded products, etc. Applications are being made in the field of

In particular, a foam sheet containing a polyester resin has a foaming layer composed of a resin composition containing a polyester resin, so it is excellent in light weight and strength, so it can be used as a sheet-shaped molded article as it is, and three-dimensional such as thermoforming It can be molded into a molded body having a typical shape.

When molding a polymer resin by continuous extrusion foaming, it is important to control the viscosity of the molten resin, but the polyester resin has a low melt viscosity compared to the existing foamed resin, so there is a problem that the viscosity must be controlled by mixing additives to increase the viscosity. . In addition, crosslinking agents added for extrusion and foaming of polyester resin include dianhydrides such as pyromellitic dianhydride. There is a problem in that the thickening effect is not achieved due to thermal decomposition.

In order to improve this problem, Patent Document 1 discloses a technique for preparing and inputting a crosslinking agent as a masterbatch. However, as a large amount of low-melting-point polyethylene (PE) contained as the base resin of the masterbatch is added, it causes uneven mixing with the polyester resin, and thus there is a limit in that the physical properties of the foamed molded article produced are deteriorated.

European 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 mixing uniformity with a foaming resin, and a method for manufacturing a foam sheet having excellent foaming ratio and physical properties by using the same is intended to provide

Masterbatch composition according to an embodiment of the present invention is a polyester resin 55 to 85% by weight; 10-40 wt% of polyolefin resin; and 1 to 30% by weight of the polyfunctional compound.

At this time, the average particle size of the polyester resin may be 600 ~ 2,000㎛, the average particle size of 70% or more of the polyester resin may be 800 ~ 2,000㎛.

The polyester resin may be polyethylene terephthalate (PET), and the polyolefin resin may be linear low density polyethylene (LLDPE).

The polyfunctional compound is pyromellitic dianhydride, 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, 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 Water, 2,2',3,3'-biphenyltetracarboxylic dianhydride, hydroquinone bisether dianhydride, bis(3,4-dicarboxyphenyl)sulfoxide dianhydride and 3,4,9,10-phene It may be at least one selected from the group consisting of rylene tetracarboxylic dianhydride.

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

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

In one example, the manufacturing method of the foam sheet, a masterbatch composition comprising 55 to 85% by weight of a first polyester resin, 10 to 40% by weight of a polyolefin resin and 1 to 30% by weight of a polyfunctional compound; a second polyester resin; and mixing inorganic particles containing an alkaline earth metal carbonate to prepare a resin melt; and extruding and foaming the resin melt with an extruder.

The resin melt is 1 to 30% by weight of the masterbatch composition; 50 to 95% by weight of the second polyester resin; and 1 to 30% by weight of the inorganic particles.

In addition, the alkaline earth metal element is at least one selected from the group consisting of Ca, Mg and Ba, and the average size of the inorganic particles may be 1-5 μm.

On the other hand, the foam seat according to an embodiment of the present invention is manufactured by the above manufacturing method, the average foaming density according to KS M ISO 845:2012 is 100 to 600 kg/m ³ , and the average thickness can be 1.0 to 5.0 mm have.

The masterbatch composition according to an embodiment of the present invention contains a polyester resin as a main component together with a polyfunctional compound, and by controlling the size of the pulverized particles of the polyester resin, when extruding and foaming the polyester resin, Uniform mixing can be achieved.

For this reason, since it is possible to prevent thermal decomposition of the additives mixed in the resin melt during extrusion and foaming of the polyester resin, there is an advantage in that the process stability is excellent and the foaming ratio of the foam sheet produced is excellent.

Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The singular expression includes the plural expression unless the context clearly dictates otherwise.

Hereinafter, embodiments of the present invention will be described in more detail.

The masterbatch composition according to an embodiment of the present invention may include a polyester resin, a polyolefin resin, and a polyfunctional compound. In this case, the polyester resin and the polyolefin resin correspond to components used for mixing and commercialization to impart compatibility as a carrier resin, and the polyfunctional compound corresponds to a compound that improves the viscosity of the foamed resin.

First, the masterbatch composition includes a polyester resin as a carrier resin. As the carrier resin of the masterbatch composition is the same as the foaming resin, uniform mixing with the foaming resin can be achieved during extrusion and foaming of the foamed resin.

The content of the polyester resin may be 55 to 85% by weight, specifically 60 to 85% by weight, and more specifically 70 to 85% by weight based on the total weight of the masterbatch composition. If the content of the polyester resin is less than 55% by weight, it may cause a non-uniform mixing with the foaming resin, thereby reducing the physical properties of the foam produced. Since the content of the added polyfunctional compound is lowered, the effect of improving the viscosity of the foamed resin may be insignificant.

Examples of the polyester resin include an aromatic or aliphatic polyester resin synthesized from a dicarboxylic acid component and a glycol component or hydroxycarboxylic acid. Non-limiting examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polyglycolic acid (PGA). , at least one selected from the group consisting of polyethylene adipate (Polyehtyleneadipate, PEA), polyhydroxyalkanoate (PHA), polytrimethylene terephthalate (PTT) and polyethylene naphthalate (PEN). can Specifically, in the present invention, polyethylene terephthalate may be used as the polyester resin.

In addition, the polyester resin may have an intrinsic viscosity (IV) of 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 0.7 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.

On the other hand, the average particle size of the polyester resin in the masterbatch composition may be 600 ~ 2,000㎛, preferably 800 ~ 2,000㎛, more preferably 1,000 ~ 2,000㎛. If the average particle size of the polyester resin in the masterbatch composition is less than the above range, especially when it is less than 800 μm, the particle size of the polyester resin is too small, so that it is not easy to handle in the masterbatch manufacturing process. In addition, the average particle size of 70% or more of the polyester resin may be 800 to 2,000 μm, preferably 1,000 to 2,000 μm, and more preferably 1,200 to 2,000 μm.

In addition, the masterbatch composition includes a polyolefin resin as a carrier resin.

The content of the polyolefin resin may be 10 to 40% by weight based on the total weight of the masterbatch composition, specifically 10 to 30% by weight, more specifically 10 to 20% by weight. When the content of the polyolefin resin is less than 10% by weight, the processability and moldability of the masterbatch composition may be deteriorated. The physical properties of the expanded molded article may be deteriorated by causing non-uniform mixing with the mixture.

Examples of such polyolefin resins include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP) selected from the group consisting of There may be more than one type. For example, the polyolefin resin is a linear low density polyethylene.

In addition, the masterbatch composition includes a polyfunctional compound that improves the viscosity by crosslinking with the foaming resin.

The content of the polyfunctional compound may be 1 to 30% by weight, specifically 5 to 30% by weight, and more specifically, 10 to 30% by weight based on the total weight of the masterbatch composition. . When the content of the polyfunctional compound is less than 1% by weight, the effect of improving the viscosity of the foamed resin may be insignificant, and when the content exceeds 30% by weight, the processability of the masterbatch composition may be reduced.

Such polyfunctional compounds include pyromellitic anhydride (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, 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 dianhydride and 3, It may be at least one selected from the group consisting of 4,9,10-perylene tetracarboxylic dianhydride. Specifically, in the present invention, pyromellitic dianhydride may be used as the polyfunctional compound.

In this case, the melting point of the polyfunctional compound may be 270°C or higher, and specifically, 270°C to 350°C, 270°C to 330°C, 270°C to 310°C, or 270°C to 290°C. As an example, when the polyfunctional compound is pyromellitic dianhydride (PMDA), the melting point may be 280±5°C.

In addition, the masterbatch composition of the present invention may further include conventionally known additives, for example, antioxidants, heat stabilizers, fillers, fireproof materials, mold release agents, colorants and other materials to improve the processability or physical properties of the resin. . Specifically, in the present invention, a heat stabilizer may be used as an additive.

The heat stabilizer may include a pentavalent and/or trivalent phosphorus compound, or a phenol-based compound having a large chemical structural steric hindrance. Specifically, the pentavalent and/or trivalent phosphorus compound may include trimethylphosphite, phosphoric acid, phosphorous acid, tris(2,4-di-tert-butylphenyl)phosphite, and the like, and a phenolic compound having a large chemical structural steric hindrance. The compound is 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)propionate (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-triyl)propion ester](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,N'-(Hexane) -1,6-diyl)bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide)) In addition, the content of the heat stabilizer is determined in the masterbatch composition It may be 0.1 to 1% by weight based on the total weight of, but is not limited thereto.

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

On the other hand, the method for producing a master batch composition according to an embodiment comprises the steps of pulverizing a polyester resin; and extruding the pulverized polyester resin, polyolefin resin and polyfunctional compound with an extruder to pelletize.

Here, the detailed description of the polyester resin, the polyolefin resin, and the polyfunctional compound is the same as described above, and the overlapping description will be omitted.

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

In the pelletizing step, the pelletizing process temperature may be 200 ℃ or less, preferably 180 ~ 190 ℃. The pelletizing process temperature is lower than the melting point of the polyester resin and the polyfunctional compound of the masterbatch composition, and is higher than the melting point of the polyolefin resin. Accordingly, the polyester resin in the pelletized masterbatch can maintain the average particle size in the above-mentioned pulverizing step. In addition, since the polyester resin and the polyfunctional compound are not melted in the process of pelletizing, the reaction between the polyester resin and the polyfunctional compound can be prevented, and thus the polyfunctional compound can be prevented from being thermally decomposed. As a result, since it is possible to prevent thermal decomposition of the additives mixed in the resin melt during extrusion and foaming of the polyester resin, there is an advantage in that the process stability is excellent and the foaming ratio of the foam sheet produced is excellent.

In addition, the present invention also provides a method for manufacturing a foam sheet using the above-described masterbatch composition.

A method for manufacturing a foam sheet according to an embodiment includes a masterbatch composition comprising a first polyester resin, a polyolefin resin, and a polyfunctional compound; a second polyester resin; and mixing inorganic particles containing an alkaline earth metal carbonate to prepare a resin melt; incorporating a blowing agent into the resin melt to form a foamable melt; and extruding and foaming the foamable melt to prepare a foam sheet.

Preparing the resin melt may be performed at a temperature of 260 ~ 300 ℃.

In addition, the resin melt is 1-30% by weight of the masterbatch composition; 50 to 95% by weight of the second polyester resin; and 1 to 30% by weight of inorganic particles.

The content of the masterbatch composition may be 1 to 30% by weight based on the total weight of the resin melt, and specifically may be 1 to 10% by weight. At this time, when the content of the masterbatch composition is less than 1% by weight, it is difficult to express the desired effect of improving the viscosity of the foamed resin, and when it exceeds 30% by weight, problems such as decrease in workability may occur.

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 the same as described above, and are the same as the polyester resin which is the carrier resin of the masterbatch composition. In addition, the polyester resin may have the form of pellets, granules, beads, chips, and the like, and in some cases may be in the form of powder.

Since the resin melt contains alkaline earth metal carbonate, the size of the cells of the foam sheet can be reduced and the density can be increased, and the sheet surface can be uniform to reduce the occurrence of corrugation, and excellent thermoformability can be exhibited. . In addition, since calcium carbonate is uniformly distributed in the polyester resin, the foam sheet obtained by extruding and foaming the resin has high thermal conductivity, thereby solving the problem of tearing of the foam sheet during molding of the foam sheet.

The alkaline earth metal element may be an inorganic carbonate containing at least one cation selected from the group consisting of Ca, Mg, and Ba. Specifically, the inorganic particles containing the alkaline earth metal carbonate may include calcium carbonate (CaCO ₃ ), magnesium carbonate (MgCO ₃ ) and barium carbonate (BaCO ₃ ), and more specifically, the inorganic particles of the present invention include calcium carbonate may include

The average size of the inorganic particles may be 1.0 to 5.0㎛. For example, the average particle size of the inorganic carbonate may be 1.0 to 4.0㎛, 1.0 to 3.0㎛, 1.0 to 2.0㎛, 2.0 to 5.0㎛, or 3.0 to 5.0㎛.

In addition, inorganic particles containing alkaline earth metal carbonate may be mixed with a polyester resin and a masterbatch composition in the form of a masterbatch to prepare a resin melt.

For example, the step of extruding foaming comprises a hydrophilic agent, a heat stabilizer, a waterproofing agent, a cell size enlarger, an infrared attenuator, a plasticizer, a fire protection chemical, a pigment, an elastomer, an extrusion aid, an antioxidant, an antistatic agent and a UV absorber. One or more additives selected from the group may be introduced into the fluid connection line. Among the additives required for manufacturing the foam sheet, additives not added during the fluid connection line may be added during the extrusion process.

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 , a mixture series of polyol and polyurethane resin, a mixture series of acrylic polymer and polyurethane resin, polyimide series, and a mixture series of cyanoacrylate and urethane.

Examples of the blowing agent include _{physical blowing agents such as N 2} , CO ₂ , Freon, butane, pentane, neopentane, hexane, isohexane, heptane, isoheptane, and methyl chloride. Specifically, butane may be used in the present invention. have.

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

Average foaming density according to KS M ISO 845:2012 of the manufactured foam sheet is 100 to 600 kg/m ³ , 100 to 500 kg/m ³ , 100 to 400 kg/m ³ , 100 to 300 kg/m ³ , 100 to 200 kg/m ³ , 200 to 600 kg/m ³ , 300 to 600 kg/m ³ , 400 to 600 kg/m ³ , or 500 to 600 kg/m ³ .

In addition, 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 to 1.5 mm, 1.5 to 5.0 mm, 2.0 to 5.0 mm , 3.0 to 5.0 mm, or 4.0 to 5.0 mm.

Hereinafter, the present invention will be described in detail by way of Examples. 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) was dried at 130° C. to remove moisture, and pulverized to have an average particle size of 600 to 2,000 μm. At this time, the average particle size of 70% or more of the pulverized PET was 800 to 2,000 μm. Thereafter, 60% by weight of pulverized PET, 29.9% by weight of linear low-density polyethylene (LLDPE), 10% by weight of pyromellitic dianhydride (PMDA) and 0.1% by weight of a heat stabilizer (Iganox 1010) were mixed to prepare a composition, and prepared The composition was pelletized at 185°C using an extruder to prepare a masterbatch.

[Preparation Examples 2-3 and Comparative Preparation Example 1]

Each master batch was prepared in the same manner as in Preparation Example 1, except that the contents of PET, LLDPE, PMDA and heat stabilizer were adjusted as shown in Table 1 below.

[Comparative Preparation Example 2]

Instead of the pulverized PET used in Preparation Example 1, the pulverized PET having an average particle size of 100 to 300 μm and an average particle size of 80% or more of the pulverized PET was 100 to 200 μm was used. Thereafter, each masterbatch was prepared in the same manner as in Preparation Example 1, except that the contents of PET, LLDPE, PMDA and heat stabilizer were adjusted as shown in Table 1 below.

PET average particle size (μm) PET
(wt%) LLDPE
(wt%) PMDA
(wt%) heat stabilizer
(wt%) Preparation Example 1 600~2,000 60 29.9 10 0.1 Preparation 2 600~2,000 65 24.9 10 0.1 Preparation 3 600~2,000 70 19.9 10 0.1 Comparative Preparation Example 1 600~2,000 44.9 45 10 0.1 Comparative Preparation Example 2 100-300 44.9 45 10 0.1

[Example 1]

In order to prepare the polyester foam sheet, first, 100 parts by weight of polyethylene terephthalate (PET) resin was dried at 180° C. to remove moisture, and 92.5 wt% of PET resin from which moisture was removed in an extruder, masterbatch prepared in Preparation Example 1 4.5% by weight of the composition and 3% 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. Then, 1.5 parts by weight of butane as a foaming agent was added to the extruder based on 100 parts by weight of PET resin, and the resin melt was cooled to 250±2° C. The cooled resin melt was extruded while passing through a die, and a PET foam sheet having an average thickness of 2.0 mm was prepared. At this time, the density of the prepared PET foam sheet was 350 kg/m ³ .

[Examples 2 and 3]

Foam sheets were each prepared in the same manner as in Example 1, except that the master batch compositions prepared in Preparation Examples 2 and 3 were used instead of the master batch composition prepared in Preparation Example 1, respectively.

[Comparative Example 1 and Comparative Example 2]

Foam sheets were each prepared in the same manner as in Example 1, except that the master batch compositions prepared in Comparative Preparation Examples 1 and 2 were used instead of the master batch composition prepared in Preparation Example 1.

[Experimental example]

The physical properties of the foam sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and fairness during manufacturing were evaluated. Specifically, physical properties and fairness were measured as follows, and the results are shown in Table 2 below.

1) Measurement of intrinsic viscosity (IV)

After dissolving the foam sheet in a mixed solution of phenol/tetrachloroethane (mixing ratio: 50% by weight/50% by weight) to prepare a solution having a concentration of 0.5% by weight, the viscosity of the solution was measured at 35° C. using an Uberod viscometer. .

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 at regular intervals and the thickness was measured using an indicator (ID-C112, Mitutoyo Corporation), and then the average value was calculated.

In addition, in order to measure the average foaming density of each foam sheet, after taking a sample of each foam sheet with a width of 2 cm Х length of 2 cm, the foam density was measured with an underwater electron density meter (EW300SG, MIRAGE).

3) Fairness evaluation

The foaming fairness of the foam sheet was evaluated with the uniformity of the measured density after the density was measured by selecting a plurality of samples at random among the produced foam sheets. Specifically, from 30 minutes after the start of foam sheet production to the end of production, 10 samples were randomly selected and the density was measured in the same manner as described above, and a deviation was derived based on the average density value of the 10 samples measured.

intrinsic viscosity
(dl/g) thickness
(mm) density
(kg/m ³ ) Density deviation
(%) Example 1 1.2 2.0 330 2±0.5 Example 2 1.1 2.2 330 3±0.5 Example 3 1.1 2.0 340 4±0.5 Comparative Example 1 1.0 2.0 350 12±0.5 Comparative Example 2 1.0 2.0 330 5±0.5

As can be seen in Table 2, the masterbatch composition according to Preparation Example contains a polyester resin (PET) as a main component together with a polyfunctional compound (PMDA), so that when extrusion and foaming of the polyester resin, the polyester foaming resin and As a result of uniform mixing of the foam sheets according to Examples 1 to 3, it was confirmed that they had higher intrinsic viscosity compared to Comparative Examples.

In addition, the foam sheets according to Examples 1 to 3 showed that the density deviation was lower than that of Comparative Example 1. This prevents thermal decomposition of the additives mixed in the resin melt during extrusion and foaming of the polyester resin, so it can be confirmed that the process stability is excellent and the foaming ratio of the manufactured foam sheet is excellent. In addition, in the case of Comparative Example 2, the foaming property was equivalent to that of Example, but the average particle size of the polyester resin in the master batch was too small, so that it was not easy to handle in the master batch manufacturing process.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art or those having ordinary skill in the art will not depart from the spirit and scope of the present invention described in the claims to be described later. It will be understood that various modifications and variations of the present invention can be made without departing from the scope of the present invention.

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

Claims (9)

delete delete delete masterbatch composition; polyethylene terephthalate resin; and mixing inorganic particles containing an alkaline earth metal carbonate to prepare a resin melt; and
Extruding and foaming the resin melt with an extruder,
The masterbatch composition comprises 55 to 85 wt% of a polyethylene terephthalate (PET) resin; Linear Low Density Polyethylene (LLDPE) resin 10-40% by weight; and 1 to 30% by weight of a polyfunctional compound, wherein the average particle size of the polyethylene terephthalate resin is 1,000 to 2,000 μm, and the average particle size of 70% or more of the polyethylene terephthalate resin is 1,200 to 2,000 μm. Way. 5. The method of claim 4,
The resin melt is 1 to 30% by weight of the masterbatch composition; 50 to 95% by weight of the polyethylene terephthalate resin; and 1 to 30% by weight of the inorganic particles. 5. The method of claim 4,
The alkaline earth metal element is at least one selected from the group consisting of Ca, Mg and Ba, and the average size of the inorganic particles is 1 to 5 μm. It is prepared by the manufacturing method according to any one of claims 4 to 6,
According to KS M ISO 845:2012, the average foaming density is 100 to 600 kg/m ³ , and the average thickness is 1.0 to 5.0 mm. delete delete