KR20230048746A - Carbon-neutral eco-friendly foam sheet and articles obtained therefrom - Google Patents

Abstract

The present invention relates to a carbon-neutral eco-friendly foam sheet, which is a multilayer sheet comprising a foam sheet layer (A) and a cover layer (B) on one or both sides, wherein 1) the foam sheet layer (A) consists of a foam sheet molded from a polypropylene resin composite containing 30 to 80 wt% of inorganic substances, a polypropylene resin with a melt tension (cN) of 30 to 100 is used as the polypropylene resin, and 2) the cover layer (B) is made of polypropylene resin or resin composite. The eco-friendly foam sheet and products obtained therefrom according to the present invention have excellent toughness, heat resistance (microwave compatibility), thermal insulation, product formability, appearance/recyclability, and economic efficiency, can be recycled by a single material when discarded, and when incinerated instead of being recycled, generate a drastically small amount of carbon dioxide by containing a very small amount of synthetic resin, to be able to respond carbon neutrality.

Description

Carbon-neutral eco-friendly foam sheet and articles obtained therefrom}

The present invention relates to a carbon-neutral eco-friendly foam sheet and articles obtained therefrom.

More specifically, it has excellent toughness, heat resistance (microwave suitability), heat retention, article moldability, appearance/recyclability and economy, and is recyclable by a single material when discarded, and relates to a carbon neutral friendly foam sheet and an article obtained therefrom. will be.

In addition, the foam sheet and products obtained therefrom are not recycled, and even when incinerated, the amount of carbon dioxide generated is remarkably low due to the very small amount of synthetic resin contained therein, and thus, it relates to an eco-friendly foam sheet capable of responding to carbon neutrality and a product obtained therefrom.

Instead of the recent sharp decline in the offline market, for example, the online market is rapidly increasing due to the excellent convenience of delivery to a desired place only with a mobile phone order. In the same vein, as the online food delivery market grows rapidly, the usage of various containers such as plastic round trays and square trays, which are essential for this, is exploding.

In particular, when the food put in these containers is hot rice, soup, etc., there is a problem with cooling down during delivery, so heat retention is required to be kept warm, and microwave ovens are often used to quickly reheat it when it cools down. The heat resistance of a container with range cooking suitability is required.

Among the above requirements, as a method of solving heat retention, a polyethylene foam container having excellent economy can be used, but there is a serious problem in that it is not recycled because it is usually made of a crosslinked polyethylene foam container to secure toughness. In addition, the non-crosslinked polyethylene foam container can be recycled, but has a problem in that it is practically impossible to use due to low toughness. In addition, its heat resistance is poor, making it unsuitable for microwave cooking.

Therefore, containers made of polypropylene are most widely used, which have poor heat retention, but have excellent toughness, heat resistance (microwave suitability), recyclability, and economy.

However, these containers made of polypropylene can be recycled when discarded after use, but most of them are not, and are incinerated, which is a problem of generating carbon dioxide. also desperately needed

As a method of improving heat retention, polypropylene foam containers can be mentioned as an alternative, but there is a problem of very poor moldability due to sagging during vacuum forming, and there is a problem that it cannot be recycled after disposal and the amount of carbon dioxide is still high when incinerated. A solution is desperately needed.

In order to solve the above problems, the present inventors have reached the present invention as a result of repeated research. That is, the present invention has excellent toughness, heat resistance (microwave suitability), heat retention, article moldability, appearance/recyclability and economy, and can be recycled by a single material when discarded, and if not recycled, the synthetic resin contained when incinerated As the amount is very small, it is intended to provide an eco-friendly foam sheet and products obtained therefrom that can respond to carbon neutrality because the amount of carbon dioxide is remarkably low.

In addition, the present invention is to provide a new polypropylene foam that solves the problem of sagging during vacuum molding in the case of conventional polypropylene foam, an eco-friendly foam sheet including the same, and an article obtained therefrom.

The present invention has excellent toughness, heat resistance (microwave suitability), heat retention, product moldability, appearance/recyclability and economy, and can be recycled by a single material when discarded, and if not recycled, the amount of synthetic resin contained when incinerated It relates to an eco-friendly foam sheet capable of responding to carbon neutrality due to a remarkably small amount of carbon dioxide generated and an article obtained therefrom.

One aspect of the present invention is a multi-layer sheet comprising a foam sheet layer (A) and a cover layer (B) on one side or both sides,

1) The foam sheet layer (A) is composed of a foam sheet molded from a polypropylene resin composite containing 30 to 80% by weight of an inorganic material, and a polypropylene resin having a melt strength (cN) of 30 to 100 cN as the polypropylene resin contains,

2) The surface of the foam sheet layer further includes a cover layer (B), and the cover layer (B) relates to a carbon-neutral eco-friendly foam sheet made of polypropylene resin.

Another aspect of the present invention is that the inorganic material is calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, calcium chloride, calcium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide, titanium oxide, alumina, mica, asbestos powder, It relates to a carbon-neutral eco-friendly foam sheet that is at least one selected from zeolite, silicate clay, and mixtures thereof.

Another aspect of the present invention relates to a carbon-neutral eco-friendly foam sheet in which the polypropylene resin is a polypropylene homopolymer or a polypropylene copolymer.

Another aspect of the present invention is that the cover layer (B) made of the polypropylene resin is made of a polypropylene resin or made of a polypropylene resin composite material further containing an inorganic material in the polypropylene resin. it's about

Another aspect of the present invention relates to a carbon-neutral eco-friendly foam sheet in which the foam sheet is a sheet formed by extrusion foaming by containing a foaming agent in a polypropylene-based resin composite.

Another aspect of the present invention relates to a carbon-neutral eco-friendly foam sheet in which the foaming agent is at least one selected from hydrocarbon-based volatile foaming agents, inorganic gas foaming agents, and mixtures thereof.

Another aspect of the present invention relates to a carbon-neutral eco-friendly foam sheet in which the hydrocarbon-based volatile blowing agent is at least one selected from propane, n-butane, iso-butane, n-pentane, and mixtures thereof.

Another aspect of the present invention relates to a carbon-neutral eco-friendly foam sheet in which the inorganic gas blowing agent is at least one selected from carbon dioxide, nitrogen, air, and mixtures thereof.

Another aspect of the present invention relates to a carbon-neutral eco-friendly foam sheet, which is a multi-layer sheet obtained by extrusion-coating a resin or a resin composite for a cover layer (B) on one or both surfaces of the foam sheet layer (A).

Another aspect of the present invention is a multilayer obtained by co-extrusion molding using the polypropylene-based resin composite as the foam sheet layer (A) and using a resin or resin composite for the cover layer (B) as one or both surfaces of the foam sheet layer. It relates to a carbon-neutral eco-friendly foam sheet that is a sheet.

Another aspect of the present invention relates to a carbon-neutral, eco-friendly foam sheet in which the thickness fraction of the foam sheet layer (B) in the multi-layer sheet is 50 to 95%.

Another aspect of the present invention relates to an article obtained by a method selected from pressure molding, pressure vacuum molding, and vacuum molding of the foam sheet.

An object of the present invention is to have excellent toughness, heat resistance (microwave suitability), heat retention, article moldability and economy, and can be recycled by a single material when discarded, and if it is not recycled and the amount of synthetic resin contained during incineration is very small, Accordingly, it is intended to obtain an eco-friendly foam sheet capable of responding to carbon neutrality with a remarkably low amount of carbon dioxide and an article obtained therefrom.

In addition, as the polypropylene resin of the foam sheet layer of the present invention, by using a polypropylene resin having a melt tension (cN) of 30 to 100 cN, sagging does not occur even when the foam sheet layer is vacuum-formed, and surface smoothness during molding is improved. very good.

An important point of focus of the present invention is to drastically reduce the amount of carbon dioxide generated proportionally by drastically reducing the content of synthetic resin in an article such as a container made of synthetic resin. In addition, as the content of synthetic resin has decreased, it is intended to improve economic feasibility by introducing inorganic materials that are very inexpensive compared to synthetic resin. In addition, they came up with an innovative method to further reduce the synthetic resin content by the foaming ratio by manufacturing foam products through the foaming process. Unfortunately, however, as a result of using a conventional polypropylene resin, it was not possible to secure the desired product moldability, resulting in great difficulties in solving the problem.

As a result of repeated studies, the present inventors used a polypropylene resin with a melt tension (cN) of 30 to 100 cN as the polypropylene resin in manufacturing a foam sheet molded from a polypropylene resin composite containing a large amount of inorganic materials, , As a result of manufacturing a multi-layer sheet including a cover layer on one side or both sides and an article obtained therefrom, it has excellent toughness, heat resistance (microwave compatibility), heat retention, product moldability, appearance / recyclability and economy, and when discarded, a single The present invention was completed by finding that recycling is possible depending on the material, and if it is not recycled and the amount of synthetic resin contained during incineration is very small, the amount of carbon dioxide generated is remarkably small, making it possible to respond to carbon neutrality.

In the present invention, the inorganic material is calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, calcium chloride, calcium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide, titanium oxide, alumina, mica, asbestos powder, zeolite , silicate clay, and at least one selected from mixtures thereof. Inorganic materials may be spherical, plate-shaped, needle-shaped, etc., but spherical ones with good dispersibility in polypropylene resin are preferable, and untreated inorganic materials are also good, but those surface-treated with compounds such as stearic acid are preferable because of good dispersibility. If the amount of inorganic substances added is less than 30% by weight, the carbon neutral effect due to the reduction of carbon dioxide generation during incineration due to the decrease in the content of synthetic resin is small, and if it exceeds 80% by weight, the carbon neutral effect is excellent, but it is difficult to foam molding and there is a risk of deterioration in toughness. there is. The average particle diameter of the inorganic material is not limited, but is preferably in the range of 0.01 to 20 μm, more preferably in the range of 0.1 to 5 μm.

In the present invention, the polypropylene resin is a polypropylene homopolymer or a polypropylene random copolymer or a polypropylene block copolymer containing propylene as a main component. The melt index (g/10 min, 230° C., 2.16Kg) of the polypropylene resin is not limited, but is preferably in the range of 0.1 to 50, more preferably in the range of 1 to 40.

In general, polypropylene resin has a molecular chain structure without branches, making it difficult to manufacture a continuous extrusion foam sheet due to its low melt tension. formed, making it impossible to obtain a good foam seat. In addition, when the foam sheet is produced, the foam sheet is broken due to the low tension of the foam before winding on the winding roll, making stable production impossible.

In the present invention introduced to solve these disadvantages, the polypropylene resin having a melt tension (cN) of 30 to 100 cN is a molecular chain having a large amount of side branches using various methods such as electron beam crosslinking, reactive extrusion, and polymerization. As a polypropylene resin modified in structure, the melt tension (cN) is measured by using, for example, Rheotens 71.97 equipment from Gottfert, Germany, putting the resin in a single screw extruder, extruding at 200 ° C and 50 rpm, and extruding at 50 rpm under the die. It is measured by mounting the tension, and the rheotens is equipped with four wheels for stretching of the resin, and the stretching speed can be measured with constant acceleration at the same ratio (0.1s ^-1 ).

A specific example of a polypropylene resin having a melt strength (cN) of 30 to 100 cN is polypropylene (Borealis, trade name DAPLOY, grade WB135HMS) with a melt strength (cN) of 32 and a melt index of 2.4 (g/10 min, 230°C, 2.16Kg). , polypropylene (Borealis, product name DAPLOY, grade WB140HMS) with a melt strength (cN) of 36 with a melt index of 2.1 (g/10 min, 230℃, 2.16Kg), a melt index of 1.9 (g/10 min, 230℃, 2.16Kg) ) of melt strength (cN) of 40 polypropylene (ExxonMobil, product name Achieve Advanced, Grade PP6302E1), melt index of 2.5 (g / 10 min, 230 ℃, 2.16Kg) of melt strength (cN) of 65 polypropylene (Sabic, brand name PP-UMS, grade 561P), and the like. If the melt strength (cN) of the polypropylene resin is less than 30, desired article moldability cannot be obtained, and if it exceeds 100, toughness may be insufficient.

In the present invention, the foam sheet is molded by extrusion foaming by containing a foaming agent in a polypropylene resin composite.

In the present invention, the foaming agent may be at least one selected from hydrocarbon-based volatile foaming agents, inorganic gas foaming agents, and mixtures thereof. The hydrocarbon-based volatile blowing agent is at least one selected from propane, n-butane, iso-butane, n-pentane, and mixtures thereof, and the inorganic gas blowing agent is at least one selected from carbon dioxide, nitrogen, air, and mixtures thereof. The addition amount of the foaming agent is selected depending on the type of foaming agent and the target foaming ratio, but in general, the amount of foaming agent used is preferably 1 to 20 parts by weight, more preferably 5 to 10 parts by weight, based on 100 parts by weight of the polypropylene resin. If it is less than 1 part by weight, the foaming effect may be insufficient.

As a raw material for the cover layer (B) according to the present invention, it is possible to use only polypropylene resin, but it may be a polypropylene resin composite material further containing an inorganic material. The addition amount of the inorganic material is preferably in the range of 5 to 50% by weight. If more inorganics are included, the carbon neutral effect and economical efficiency may be improved, but if too much, the appearance/recyclability and product formability may be deteriorated.

The multilayer foam sheet according to the present invention may be obtained by extrusion-coating a resin or resin composite for the cover layer (B) on one or both sides of the foam sheet layer (A). The resin or resin composite for the cover layer (B) preferably has a melt index (g/10 min, 230°C, 2.16Kg) in the range of 5 to 50, more preferably in the range of 20 to 40. The extrusion coating temperature is preferably in the range of 250 to 350 ° C, more preferably in the range of 280 to 320 ° C.

Another method of obtaining a multi-layer foam sheet according to the present invention is to co-extrude the polypropylene resin composite material as the foam sheet layer (A) and a resin or resin composite material for the cover layer (B) as one or both surfaces of the foam sheet layer It can be obtained by molding.

In a two-layer or three-layer extrusion sheet molding machine equipped with a device capable of injecting a foaming agent into the extruder for the foam sheet layer, the polypropylene resin composite is put into the extruder for the foam sheet layer (A), and the resin or resin composite is used as the cover layer (B). A multi-layer foam sheet can be obtained by co-extruding and foaming molding on one side or both sides of the foam sheet layer by putting it into an extruder for.

The thickness fraction of the foam sheet layer (B) in the multi-layer sheet is preferably 50 to 95%. If the thickness fraction is less than 50%, the desired carbon neutral effect cannot be obtained, and if it exceeds 95%, there is a concern that the appearance/recyclability may be deteriorated.

The article according to the present invention can be obtained by a molding method selected from pressure molding, pressure vacuum molding, and vacuum molding of the multilayer foam sheet of the base material. This will be briefly explained as follows.

First, pressure molding is produced using a lower mold and an upper case in which a plurality of intaglio shapes such as a container of the present invention are formed. A multilayer foam sheet heated to an appropriate temperature is placed on the lower mold and the upper case is In the state covered on the lower mold, the multi-layer foam sheet is made into the shape of an article such as a container while being closely adhered to the lower mold by air pressure generated by blowing high-pressure air into the upper case. In this way, when a plurality of article shapes such as containers of the present invention are formed on the multilayer foam sheet in close contact with the lower mold, the multilayer foam sheet is separated from the lower mold and then the shape of each article such as container is cut to complete the article, such as a complete container. do. At this time, it is better if the mold surface of the lower mold is coated with a coating agent before placing the multi-layer foam sheet in order to smoothly separate the multi-layer foam sheet from the lower mold.

Next, in the second pressure vacuum molding, the upper case and lower mold of the pressure forming are used as they are, but a plurality of suction holes connected to the mold surface are formed in the lower mold, and high-pressure air is blown into the upper case and at the same time By sucking air out of the mold surface through the suction hole, the multi-layer foam sheet adheres to the mold surface to complete the shape of the article such as the container of the present invention. Here, before molding an article such as a container by sucking air through the suction hole, degassing is performed through the same suction hole, and the multilayer foam sheet in which the shape of the article such as the container of the present invention is completed is separated from the mold surface of the lower mold. When the heat sheet is separated, high-pressure air is blown through the suction hole. Therefore, the pressure vacuum molding is different only in that air is sucked in through the suction hole of the lower mold, and the configuration and forming method of other parts are the same as the configuration and forming method of the above-mentioned pressure forming method.

Thirdly, vacuum forming is to complete the shape of an article such as a container of the present invention only with a lower mold without an upper case, and air is sucked through a suction hole formed in the lower mold to complete the article such as a container of the present invention. The composition and molding method are the same except that high-pressure air is blown through the upper case in one pressure vacuum molding.

The eco-friendly foam sheet according to the present invention and the article obtained therefrom have excellent toughness, heat resistance (microwave suitability), heat retention, article moldability, appearance/recyclability and economy, and can be recycled by a single material when discarded, and if recycled As the amount of synthetic resin contained during incineration is very small, it is expected that it will be usefully used as an eco-friendly foam sheet capable of responding to carbon neutrality and products obtained therefrom, since the amount of carbon dioxide generated is remarkably low.

Hereinafter, an example will be described for detailed description of the present invention, but the present invention is not limited to the following examples.

Tenacity, heat resistance (suitability for microwave cooking), heat retention, article moldability, appearance/recyclability, carbon neutrality, eco-friendliness, and economy of the sheet and article samples prepared according to the following Examples and Comparative Examples were evaluated as follows.

1. Toughness

The flexural modulus (Kgf/cm ² ) of the sheet sample was measured according to ASTM D790, and tenacity was evaluated in 4 grades.

- Toughness evaluation criteria division ◎(excellent) ○ (good) △ (Normal) X (bad) flexural modulus
(Kgf/cm ² ) over 1,000 over 1,000
less than 700 over 700
less than 500 less than 500

2. Heat resistance (suitable for microwave cooking)

Prepare a square tray with a size of 170 (width) x 220 (length) x 90 (height) mm as a product sample, install it in a microwave oven (1,000W), operate it for 10 minutes, and heat resistance (electronic range cooking suitability) was evaluated.

- Evaluation criteria for heat resistance (suitability for microwave cooking) division ◎(excellent) ○ (good) △ (Normal) X (bad) degree of product deformation doesn't exist extremely rare occurrence occurs slightly occurs severely

3. Warmth

As a product sample, a square tray with a size of 170 (width) x 220 (length) x 90 (height) mm was prepared, filled with 80% of water at 90 ° C, and after 30 minutes after closing the lid, the heat retention was rated as 4 by the degree to which the temperature of the water dropped. evaluated.

- Warmth evaluation criteria division ◎(excellent) ○ (Good) △ (Normal) X (bad) temperature drop
(℃) less than 20 20+
less than 40 over 40
less than 60 over 60

4. Product moldability

As an article sample, a square tray with a size of 170 (width) x 220 (length) x 90 (height) mm was evaluated for moldability of the article into 4 grades according to the degree of sagging during vacuum forming.

- Criteria for evaluation of product formability division ◎(excellent) ○ (Good) △ (Normal) X (bad) degree of sagging doesn't exist extremely rare occurrence occurs slightly occurs severely

5. Carbon Neutral Environmentally Friendly

Prepare a standard sheet (weight 180g) made of 100 (width) x 100 (length) x 20 (thickness) mm size (200 cm ³ ) with only polypropylene resin with a density of 0.9 (g/cm ³ ) and a sheet sample of the same size to be evaluated. did The weight of synthetic resin contained in the sheet sample to be evaluated for the weight of synthetic resin per standard sheet (180g) in that carbon neutrality is inhibited due to the generation of carbon dioxide in proportion to the amount of synthetic resin contained per sheet when the product is not recycled after disposal and is incinerated. According to the ratio (%), carbon neutrality and eco-friendliness were evaluated as 4 grades.

- Carbon Neutral Eco-friendly Evaluation Criteria division ◎(excellent) ○ (Good) △ (Normal) X (bad) Synthetic resin weight ratio (%) less than 30 over 30
less than 50 over 50
less than 70 over 70

6. Appearance/recyclability

A square tray with a size of 170 (width) x 220 (length) x 90 (height) mm was prepared as an article sample. Identify the material of the synthetic resin in the raw material of the product sample, fill the square tray with 80% of the kimchi broth, close the lid, throw away the kimchi broth after 30 minutes, rinse with water once, and recycle to the extent that the traces of the soup remain on the inside of the square tray Sex was rated on a 4-star scale.

- Appearance/recyclability evaluation criteria division ◎(excellent) ○ (good) △ (Normal) X (bad) synthetic resin material single material single material single material single material or heterogeneous material Residual level of broth traces none at all very little residue insignificant residue a little over
residue

7. Affordability

A standard sheet made of 100 (width) x 100 (length) x 20 (thickness) mm size (200 cm ³ ) with only polypropylene resin having a density of 0.9 (g/cm ³ ) and a sheet sample to be evaluated of the same size were prepared. The economic feasibility was evaluated in 4 grades according to the ratio (%) of the manufacturing cost per sheet sample to be evaluated to the manufacturing cost per sheet of the manufactured standard sheet.

- Carbon Neutral Eco-friendly Evaluation Criteria division ◎(excellent) ○ (Good) △ (Normal) X (bad) Manufacturing cost ratio of evaluation target sheet to standard sheet (%) less than 80 over 80
less than 90 over 90
less than 100 over 100

[Example 1]

As raw materials for the foam sheet layer (A), inorganic calcium carbonate (CaCO ₃ ) with an average particle diameter of 1.5 μm and melt index 2.4 (g/10 min, 230℃, 2.16Kg) and melt strength (cN) of 32 polypropylene (Borealis) , trade name DAPLOY, grade WB135HMS, HMSPP-A) were prepared. A composition containing 65% by weight of HMSPP-A and 35% by weight of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding equipment to obtain polypropylene resin composite pellets (P-1).

The polypropylene resin composite pellets (P-1) were put into an extrusion foam sheet molding machine equipped with a device capable of injecting nitrogen as a foaming agent, and 4.5 parts by weight of the foaming agent was added to 100 parts by weight of HMSPP-A and foamed to obtain a thickness of 0.7mm, A polypropylene resin composite foam sheet (F-1) having a width of 910 mm and a foaming ratio of 2.0 was obtained.

As a raw material for the cover layer (B), polypropylene (Lotte Chemical, product name Hopelen, grade Y-130, PP-A) having a melt index of 4.0 (g/10 min, 230° C., 2.16 Kg) was prepared.

PP-A was put into an extrusion coating molding machine and extrusion-coated on the supplied polypropylene resin composite foam sheet (F-1) to form a two-layer foam with a thickness of 0.8mm (thickness fraction of the foam sheet layer (A): 87.5%) and a width of 910mm. A sheet (S-1) was prepared and its toughness, carbon neutrality, eco-friendliness and economy were evaluated, and the results are shown in Table 8.

In addition, a container (C-1) having a size of 185 (width) x 125 (length) x 80 (height) (mm) was prepared by vacuum molding using the obtained two-layer foam sheet (S-1), and heat resistance (electronic Range cooking suitability), heat retention, product moldability, and appearance/recyclability were evaluated, and the results are shown in Table 8.

[Example 2]

A _two- layer foam sheet having a thickness of 0.8 mm (foam sheet layer (A) thickness fraction 87.5%) and a width of 910 mm ( S-2) and container (C-2) were manufactured, and the toughness, heat resistance (suitability for microwave cooking), heat preservation, product moldability, appearance/recyclability, carbon neutrality, eco-friendliness and economic feasibility were evaluated as follows, and the results is shown in Table 8.

[Example 3]

A composition containing 35% by weight of HMSPP-A and 65% by weight of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding equipment to obtain polypropylene resin composite pellets (P-3).

Inject the polypropylene resin composite pellets (P-3) into an extrusion foam sheet molding machine equipped with a device capable of injecting nitrogen as a foaming agent, and add 3.0 parts by weight of a foaming agent to 100 parts by weight of HMSPP-A, and foam to obtain a thickness of 0.65mm, Except for obtaining a polypropylene resin composite foam sheet (F-3) having a width of 910 mm and a foaming ratio of 1.5, the same procedure as in Example 1 was performed to have a thickness of 0.70 mm (92.9% of the thickness of the foam sheet layer (A)) and a width of 910 mm A layered foam sheet (S-3) and container (C-3) were prepared, and toughness, heat resistance (suitability for microwave cooking), heat retention, product moldability, appearance/recyclability, carbon neutrality, eco-friendliness and economy were evaluated as follows. It was evaluated and the results are shown in Table 8.

[Example 4]

As a raw material for the foam sheet layer (A), polypropylene (Borealis, trade name DAPLOY, grade WB140HMS, HMSPP-B) with a melt index of 2.1 (g/10 min, 230°C, 2.16Kg) and a melt strength (cN) of 36 was prepared. .

A composition containing 40% by weight of HMSPP-B and 60% by weight of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding equipment to obtain polypropylene resin composite pellets (P-4).

The polypropylene resin composite pellets (P-4) were put into an extrusion foam sheet molding machine equipped with a device capable of injecting nitrogen as a foaming agent, and 3.5 parts by weight of the foaming agent was added to 100 parts by weight of HMSPP-A and foamed to obtain a thickness of 0.68mm, Except for obtaining a polypropylene resin composite foam sheet (F-4) having a width of 910 mm and a foaming ratio of 1.7, the same procedure as in Example 1 was performed to obtain a thickness of 0.75 mm (foam sheet layer (A) thickness fraction: 90.7%), width 2 of 910 mm. A layered foam sheet (S-4) and container (C-4) were prepared, and toughness, heat resistance (suitability for microwave cooking), heat retention, article moldability, appearance/recyclability, carbon neutrality, eco-friendliness and economy were evaluated as follows. It was evaluated and the results are shown in Table 8.

[Example 5]

Polypropylene (ExxonMobil, product name: Achieve Advanced, Grade PP6302E1, HMSPP-C) with a melt index of 1.9 (g/10 min, 230°C, 2.16Kg) and a melt strength (cN) of 40 was prepared as a raw material for the foam sheet layer (A). did

A composition containing 50 wt % of HMSPP-C and 50 wt % of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding facility to obtain polypropylene resin composite pellets (P-5). Inject the polypropylene resin composite pellets (P-5) into an extrusion foam sheet molding machine equipped with a device capable of injecting nitrogen as a foaming agent, and add 5.5 parts by weight of the foaming agent to 100 parts by weight of HMSPP-A, and foam to obtain a thickness of 0.8mm, A polypropylene resin composite foam sheet (F-5) having a width of 910 mm and a foaming ratio of 2.5 was obtained.

Polypropylene resin composite pellets (P-5) are put into an extrusion coating molding machine and extrusion-coated on both sides of the supplied polypropylene resin composite foam sheet (F-5) to have a thickness of 0.9 mm (foam sheet layer (A) thickness fraction 88.9) %), a three-layer foam sheet (S-5) having a width of 910 mm was prepared, and the toughness, carbon neutrality, and eco-friendliness thereof were evaluated, and the results are shown in Table 8. In addition, a container (C-5) having a size of 185 (width) x 125 (length) x 80 (height) (mm) was prepared by vacuum molding using the obtained three-layer foam sheet (S-5), heat resistance ( Microwave cooking suitability), heat retention, product moldability, and appearance/recyclability were evaluated, and the results are shown in Table 8.

[Example 6]

As a raw material for the foam sheet layer (A), polypropylene (Sabic, product name: PP-UMS, grade 561P, HMSPP-D) with a melt index of 2.5 (g/10 min, 230℃, 2.16Kg) and a melt strength (cN) of 65 was used. prepared.

A composition containing 50 wt % of HMSPP-D and 50 wt % of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding facility to obtain polypropylene resin composite pellets (P-6). In a three-layer extrusion foam sheet molding machine equipped with a device capable of injecting nitrogen as a foaming agent, the polypropylene resin composite pellets (P-6) are injected into the middle foam sheet layer (A) layer, and PP-6 is added to both skin layers (B). By adding A, a three-layer foam sheet (S-6) with a thickness of 0.9 mm (thickness fraction of the foam sheet layer (A) of 87.2%), a width of 910 mm and a foaming ratio of 3.0 was manufactured, and its toughness, carbon neutrality, eco-friendliness and economy were demonstrated. Evaluated and the results are shown in Table 8. In addition, a container (C-6) having a size of 185 (width) x 125 (length) x 80 (height) (mm) was prepared by vacuum molding using the obtained three-layer foam sheet (S-6), heat resistance ( Microwave cooking suitability), heat retention, product moldability, and appearance/recyclability were evaluated, and the results are shown in Table 8.

[Comparative Example 1]

PP-A was introduced into the extrusion sheet molding machine to produce a single-layer sheet (CS-1) having a thickness of 0.9 mm and a width of 910 mm, and the toughness, carbon neutrality, and eco-friendliness thereof were evaluated, and the results are shown in Table 8. In addition, a container (CC-1) having a size of 185 (width) x 125 (length) x 80 (height) (mm) was prepared by a vacuum forming method using the single-layer sheet (CS-1) obtained above, and heat resistance (microwave cooking) Suitability), heat retention, product moldability, and appearance/recyclability were evaluated, and the results are shown in Table 8.

[Comparative Example 2]

A composition containing 65 wt % of PP-A and 35 wt % of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding facility to obtain polypropylene resin composite pellets (CP-2). CP-2 was put into the extrusion sheet molding machine to prepare a single-layer sheet (CS-2) having a thickness of 0.9 mm and a width of 910 mm, and the toughness, carbon neutrality, and eco-friendliness thereof were evaluated, and the results are shown in Table 8. In addition, a container (CC-2) having a size of 185 (width) x 125 (length) x 80 (height) (mm) was prepared by a vacuum forming method using the single-layer sheet (CS-2) obtained above, and heat resistance (microwave cooking) Suitability), heat retention, product moldability, and appearance/recyclability were evaluated, and the results are shown in Table 8.

[Comparative Example 3]

Inject HMSPP-A into an extrusion foam sheet molding machine equipped with a device capable of injecting nitrogen as a foaming agent, and add 4.5 parts by weight of a foaming agent to 100 parts by weight of HMSPP-A, and foam it. A propylene foam sheet (CF-3) was obtained, and a container (CC-3) was prepared in the same manner as in Example 1, and toughness, heat resistance (suitability for microwave cooking), heat retention, product moldability, appearance / recyclability, Carbon neutral eco-friendliness and economic feasibility were evaluated as follows, and the results are shown in Table 8.

[Comparative Example 4]

Polypropylene (JPP, trade name: WAYMAX, grade EX4000, HMSPP-E) with a melt index of 6.0 (g/10 min, 230°C, 2.16Kg) and a melt strength (cN) of 19 was prepared as a raw material for the foam sheet layer (A). .

Conducted in the same manner as in Example 1 except that the composition of 50% by weight of HMSPP-E and 50% by weight of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding equipment to obtain polypropylene resin composite pellets (CP-4). to prepare a two-layer foam sheet (CS-4) and a container (CC-4) with a thickness of 0.8 mm (foam sheet layer (A) thickness fraction 87.5%) and a width of 910 mm, toughness, heat resistance (suitability for microwave cooking), Heat retention, product moldability, appearance/recyclability, carbon neutrality, eco-friendliness and economic feasibility were evaluated as follows, and the results are shown in Table 8.

[Comparative Example 5]

Polypropylene (Graft Polymer, trade name: Graftalene, grade 00100, HMSPP-F) with a melt index of 1.0 (g/10 min, 230℃, 2.16Kg) and a melt strength (cN) of 110 is prepared as a raw material for the foam sheet layer (A). did

Conducted in the same manner as in Example 1 except that the composition of 50% by weight of HMSPP-F and 50% by weight of CaCO ₃ was well dispersed in CaCO ₃ in a twin-screw extrusion compounding equipment to obtain polypropylene resin composite pellets (CP-5). to prepare a two-layer foam sheet (CS-5) and container (CC-5) with a thickness of 0.8 mm (foam sheet layer (A) thickness fraction 87.5%) and a width of 910 mm, toughness, heat resistance (suitability for microwave cooking), Heat retention, product moldability, appearance/recyclability, carbon neutrality, eco-friendliness and economic feasibility were evaluated as follows, and the results are shown in Table 8.

division foam sheet
Composition (% by weight) firing
magnification toughness heat resistance
(Microwave compatibility) warmth article
formability Exterior/
recyclability carbon neutral
eco-friendliness Economics Example 1 HMSPP-A 65
CaCO ₃ 35 2.0 ◎ ◎ ◎ ◎ ◎ ◎ ◎ Example 2 HMSPP-A 50
CaCO ₃ 50 2.0 ◎ ◎ ◎ ◎ ◎ ◎ ◎ Example 3 HMSPP-A 35
CaCO ₃ 65 1.5 ◎ ◎ ○ ◎ ◎ ◎ ◎ Example 4 HMSPP-B 40
CaCO ₃ 60 1.7 ◎ ◎ ○ ◎ ◎ ◎ ◎ Example 5 HMSPP-C 50
CaCO ₃ 50 2.5 ◎ ◎ ◎ ◎ ◎ ◎ ◎ Example 6 HMSPP-D 50
CaCO ₃ 50 3.0 ○ ◎ ◎ ◎ ◎ ◎ ◎ Comparative Example 1 PP-A 100 0 ◎ ◎ X X ◎ X X Comparative Example 2 PP-A 65
CaCO ₃ 35 0 ◎ ◎ X X ◎ △ △ Comparative Example 3 HMSPP-A 100 2.0 ○ ◎ ◎ ◎ X X X Comparative Example 4 HMSPP-E 50
CaCO ₃ 50 2.0 ◎ ◎ ◎ X X ◎ ◎ Comparative Example 5 HMSPP-F 50
CaCO ₃ 50 2.0 X ◎ ◎ ◎ X ◎ ◎

First, a foam sheet layer (A) and a polypropylene-based non-foamed cover layer (B) formed of a polypropylene resin composite filled with inorganic materials using a polypropylene resin having a melt tension (cN) of 30 to 100 according to the present invention are coated on one side or both sides In the case of a multi-layer sheet comprising (Examples 1 to 6), a sheet molded with only polypropylene resin according to the prior art and an article obtained therefrom (Comparative Example 1), a sheet molded with an inorganic-filled polypropylene resin composite and an article obtained therefrom (Comparative Example 2), in the case of a sheet molded only with a polypropylene resin having a melt strength (cN) of 30 to 100 and an article obtained therefrom (Comparative Example 3), inorganic material-filled polypropylene using a polypropylene resin having a melt strength (cN) of less than 30 In the case of a sheet molded from a resin composite and an article obtained therefrom (Comparative Example 4) and a sheet molded with an inorganic-filled polypropylene resin composite using a polypropylene resin having a melt tension (cN) of greater than 100 and an article obtained therefrom (Comparative Example 5) Compared to, the foam sheet according to the present invention and the article obtained therefrom have excellent toughness, heat resistance (microwave suitability), heat retention, article moldability and economy, and can be recycled by a single material at the time of disposal, and if not recycled As the amount of synthetic resin contained during incineration is very small, it can be seen that the amount of carbon dioxide generated is remarkably low, making it possible to respond to carbon neutrality.

Claims (12)

A multilayer sheet comprising a foam sheet layer (A) and a cover layer (B) on one or both surfaces, wherein the foam sheet layer (A) is polypropylene with 30 to 80% by weight of inorganic materials and a melt strength (cN) of 30 to 100 It is made of a polypropylene composite resin containing a resin, and the cover layer (B) is a carbon-neutral eco-friendly foam sheet made of a polypropylene resin. According to claim 1,
The inorganic material is calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, calcium chloride, calcium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide, titanium oxide, alumina, mica, asbestos powder, zeolite, silicate clay and these A carbon-neutral eco-friendly foam sheet that is at least one selected from a mixture of. According to claim 1,
The polypropylene resin is a polypropylene homopolymer or a polypropylene copolymer, carbon neutral eco-friendly foam sheet. According to claim 1,
The cover layer (B) is a carbon-neutral eco-friendly foam sheet obtained from a polypropylene resin composite containing the polypropylene resin and an inorganic material. According to claim 1,
The foam sheet is a carbon-neutral eco-friendly foam sheet that is a sheet formed by extrusion foaming by containing a foaming agent in a polypropylene resin composite. According to claim 5,
The foaming agent is a carbon-neutral eco-friendly foam sheet that is at least one selected from hydrocarbon-based volatile foaming agents, inorganic gas foaming agents, and mixtures thereof. According to claim 6,
The carbon-neutral eco-friendly foam sheet in which the hydrocarbon-based volatile blowing agent is at least one selected from propane, n-butane, iso-butane, n-pentane, and mixtures thereof. According to claim 6,
The carbon-neutral eco-friendly foam sheet in which the inorganic gas blowing agent is at least one selected from carbon dioxide, nitrogen, air, and mixtures thereof. According to claim 1,
A carbon-neutral eco-friendly foam sheet that is a multi-layer sheet obtained by extrusion-coating a resin or a resin composite for the cover layer (B) on one or both sides of the foam sheet layer (A). According to claim 1,
A carbon-neutral eco-friendly foam sheet that is a multi-layer sheet obtained by co-extrusion using the polypropylene resin composite as the foam sheet layer (A) and the resin or resin composite for the cover layer (B) as one or both surfaces of the foam sheet layer. According to claim 1,
Among the multi-layer sheets, the foam sheet layer (B) has a thickness fraction of 50 to 95% carbon-neutral eco-friendly foam sheet. An article obtained by a method selected from pressure molding, pressure vacuum molding, and vacuum molding for the foam sheet according to claims 1 to 11.