KR20020037119A - Paste composition for a disposable and bio-degradable bowl and method of preparing the bowl using same - Google Patents

Abstract

PURPOSE: A paste composition for a disposable, biodegradable container and a method for preparing the container using the composition are provided, to improve biodegradability, tensile strength, elongation, formability and water proofness. CONSTITUTION: The paste composition comprises 5-25 wt% of a poly(vinyl alcohol) resin; 30-60 wt% of a primary filler selected from the group consisting of starch, rice halls and their mixtures; 30-40 wt% of water; and optionally 0.1-20 wt% of a secondary filler and 0.1-1 wt% of an additive. Preferably the secondary filler is selected from the group consisting of lime, talc, rosin and their mixtures; and the additive is selected from the group consisting of ethylene glycol, glycerol, propylene glycol and their mixtures. The method comprises the steps of compression molding the paste composition to prepare a sheet laminated with a biodegradable polyester film; and vacuum molding the laminated sheet.

Description

Paste composition for disposable biodegradable container, and method for manufacturing container using same {PASTE COMPOSITION FOR A DISPOSABLE AND BIO-DEGRADABLE BOWL AND METHOD OF PREPARING THE BOWL USING SAME}

The present invention relates to a disposable biodegradable container paste composition and a method for producing a container using the same, specifically, a polyvinyl alcohol resin-containing paste composition for a disposable biodegradable container having excellent biodegradability, tensile strength, elongation and moldability, And a method for producing a disposable biodegradable container having improved water resistance using the composition.

Conventionally, polyesters and polycaprolactones and the like have been used to prepare disposable biodegradable containers as biodegradable resins, but they have the disadvantage of being soluble in organic solvents harmful to humans and difficult to process in solution. Therefore, in recent years, biodegradable containers are made of paper, but paper has a problem that not only emits a lot of environmental pollutants at the manufacturing stage but also has high manufacturing cost.

In addition, in preparing a disposable biodegradable container using a composition containing such a resin, a method of manufacturing a container by compression molding and then spraying the waterproof liquid to the container to dry or coating the waterproof film on the container is mainly used. However, both of these methods have a problem that the processing cost increases because a long time is required for molding the container.

Accordingly, the present inventors have diligently studied, and the biodegradable paste composition containing polyvinyl alcohol resin is sheeted and laminated with a biodegradable film, and the resulting laminated sheet is vacuum-molded to provide disposable biodegradability having excellent biodegradability and other physical properties. It has been found that the container can be easily manufactured and the present invention has been completed.

It is an object of the present invention to provide a paste composition for disposable biodegradable containers excellent in biodegradability, tensile strength, elongation and formability, and a method for producing a disposable biodegradable container having improved waterproofness using the composition.

1 is a graph showing changes in biodegradation with time by activated sludge of the compositions prepared in Examples and Comparative Examples.

In order to achieve the above object, in the present invention, (i) 5 to 25% by weight of polyvinyl alcohol resin, (ii) 30 to 60% by weight of primary filler selected from the group consisting of starch, chaff, and mixtures thereof, and (iii ) Provides a paste composition for a disposable biodegradable container comprising 30 to 40% by weight of water.

In addition, the present invention provides a method for producing a disposable biodegradable container comprising forming a laminate sheet with a biodegradable polyester film by compression molding and then vacuum forming the resulting laminated sheet.

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

The resin composition for a disposable biodegradable container according to the present invention comprises a polyvinyl alcohol resin, and 1.2 to 12 parts by weight of starch or rice hull per 1 part by weight of resin, wherein the biodegradability of the present invention to which water is added as an essential ingredient The paste composition includes secondary fillers and additives as optional ingredients.

The polyvinyl alcohol resin used in the present invention as a biodegradable resin is a fully biodegradable synthetic polymer prepared by dissolving polyvinyl acetate in an alcohol and then adding a small amount of alkali or acid thereto. And it is easy to process and has the advantage of low price compared to the conventional biodegradable synthetic polymer polyester and polycaprolactone used. In addition, the polyvinyl alcohol resin has a tensile strength of 2.4 to 7.9 kg _f / mm ² and elongation of 1 to 300% to facilitate vacuum molding, and excellent thermal stability such as thermal decomposition at 200 ° C or higher. Polyvinyl alcohol resin is used in an amount of 5 to 25% by weight of the composition of the present invention, when less than 5% by weight of the components are not easy to mix, when more than 25% by weight of the container is not formed Do not.

Starch or chaff used in the present invention is used as a kind of biodegradable filler in an amount of 30 to 60% by weight of the composition of the present invention, when less than 30% by weight lowers the biodegradability of the composition, more than 60% by weight In this case, the formulation of the components is not easy.

Secondary filler used as an optional component in the present invention, serves to control the tensile strength and elongation required for the manufacture of the container and to prevent shrinkage occurring during the drying of the molded container, such as quicklime, talc and Rosin. Secondary fillers are used in amounts of 0.1 to 20% by weight of the composition of the present invention, and when more than 20% by weight, elongation is lowered, resulting in poor moldability for container production.

In addition, the additive used as another optional component in the present invention is used for plasticizing the resin, and examples thereof include ethylene glycol, glycerol and propylene glycol. The additive is used in an amount of 0.1 to 1% by weight of the composition of the present invention, and if more than 1% by weight has the problem that the additive elutes from the resin.

According to the present invention, the above-mentioned components may be mixed with water in an amount corresponding to 30 to 40% by weight of the composition of the present invention to prepare a paste composition for disposable biodegradable container of the present invention, preferably boiling water After adding an appropriate amount of polyvinyl alcohol resin to make an aqueous polyvinyl alcohol solution, the paste composition of the present invention may be prepared by adding and stirring an appropriate amount of a primary filler, and optionally a secondary filler and an additive.

In the present invention, the paste composition prepared as described above is laminated with a biodegradable polyester film by compression molding, and then the resulting laminated sheet is vacuum molded into a desired shape to prepare a disposable biodegradable container.

Looking specifically at the lamination sheeting process by compression molding, the temperature of the upper and lower plates of the auto press (auto press) is maintained at 110 to 130 ℃, and then placed a guide of the type □ in the center and the paste composition of the present invention The polyester film is fed stepwise and then pressurized and finally cooled to sheet and laminate.

Subsequently, the container forming process by vacuum forming will be described in detail. The resulting laminated sheet is fixed to a guide of a suitable size according to the size of the mold and placed between both molds mounted on the vacuum molding machine, and then vacuum is first applied to the lower mold. After the laminated sheet is brought into close contact with the lower mold, the lower mold is pressed at a pressure of 50 to 100 atm at room temperature using the upper mold to form a container in the shape of a space present between the two molds. At this time, the vacuum molding state is maintained for 30 seconds to 2 minutes, and then the molded container is taken out of the vacuum molding machine and dried at room temperature.

Since the biodegradable polyester film used in the present invention contains less than 0.4% of water (temperature: 21 ° C, relative humidity: 65%) in the air, it contains a composition containing a polyvinyl alcohol resin having a property of dissolving in hot water; By laminating a sheet, the water resistance required for the container is greatly improved.

As such, the biodegradable paste composition of the present invention has a low cost but excellent biodegradability, tensile strength, elongation and formability, thereby making it possible to easily prepare a disposable container, and the manufactured container also has biodegradability and waterproofness. It is excellent and can be usefully used for various purposes.

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following examples.

Biodegradability and mechanical properties (tensile strength and elongation) of the paste compositions prepared in the following Examples and Comparative Examples are evaluated according to the following Reference Examples.

Reference Example 1: Determination of biodegradation by activated sludge

According to ASTM D 5209-92 standard, after mixing activated onito and composition samples in a 2L reactor, it is possible to capture and quantify the amount of CO ₂ generated during biodegradation of the sample for a certain period of time while maintaining 55 ± 2 ° C. The biodegradability (%) of the composition was measured.

Reference Example 2: Measurement of mechanical properties (tensile strength and elongation)

Specimens for UTM were fabricated from composition samples prepared using the ASTM D746 Specimen Maker. The specimens were stored for 1 week in a constant temperature and humidity room with a temperature of 20 ° C. and a relative humidity of 60%, and then the tensile strength (kg _f / mm ² ) and elongation ((%) of the composition using the ASTM D638 test method using UTM (Instron 4206). %) Was measured.

Example 1 Preparation of Paste Composition

6.7% by weight of polyvinyl alcohol resin P-17 (manufactured by Dongyang Chemical (OCI)) was added to 33.3% by weight of boiling water to make an aqueous polyvinyl alcohol solution, followed by 60% by weight of corn starch (manufactured by Samyang Genex). To prepare a biodegradable paste composition by stirring.

The biodegradability of the prepared composition was measured, and the results are shown in FIG. 1, and tensile strength and elongation were measured, and the results are shown in Table 1 below.

Examples 2-11 and Comparative Examples 1-3: Preparation of Paste Composition

A biodegradable paste composition was prepared in the same manner as in Example 1, using the components shown in Table 2 below in their respective component ratios. At this time, the additive and the secondary filler were added together when the starch was added, and the additive ethylene glycol was purchased from Samjung Chemical Co., Ltd. and the second filler, quicklime and talc, respectively, were purchased from Woolong and Western Heungup Co., Ltd. Used.

The biodegradability of the prepared composition was measured, and the results are shown in FIG. 1, and tensile strength and elongation were measured, and the results are shown in Table 1 below.

From the graph of FIG. 1, the composition according to the present invention shows a biodegradation degree of about 50% or more as the 5 days of the start of the experiment, it can be seen that the biodegradation compared to the cellulose which is a natural material shown with the biodegradability. In addition, considering that the tensile strength and elongation of the composition suitable for preparing the container are 25 to 75 kg _f / mm ² and 6 to 20%, respectively, in Table 1, the composition according to the present invention has a suitable tensile strength and elongation On the other hand, it can be seen that in Comparative Examples 1 to 3 in which the secondary filler is added in excess, the tensile strength is too high and the elongation tends to decrease.

Example 12 Preparation of Containers

The temperature of the upper and lower plates of the auto press was maintained at 120 ° C., and then a guide (25 × 25 × 2 mm) in the form of □ was placed at the center thereof, and each paste composition prepared in Examples 1 to 11 above; A polyester film (Era Chemical Co., Ltd., Cargill Co., Ltd. product) was supplied. The supplied paste composition and the polyester film were pressurized in four stages using both compressor plates and finally cooled to form a laminated sheet, and the pressurization and cooling conditions performed at this time are shown in Table 2 below.

division Pressurized conditions Cooling condition Stage 1 Tier 2 Tier 3 4 steps P Time in seconds 180 15 3 180 120 Pressure (atmospheric pressure) 5 40 50 60 70

Then, each of the resulting laminated sheets was fixed to the guide and placed between both molds mounted on the vacuum molding machine. After vacuuming the bottom mold to bring the laminated sheet into close contact with the bottom mold, the bottom mold was pressed for 1 minute at a pressure of 70 atm at room temperature using the top mold, and then formed into a space shape existing between both molds. The prepared containers were taken out of the vacuum molding machine and dried at room temperature, thereby easily preparing 11 disposable biodegradable containers having excellent physical properties.

The biodegradable paste composition of the present invention is inexpensive and has excellent biodegradability, tensile strength, elongation and moldability, thereby making it easy to prepare a disposable container, and the manufactured container is also excellent in biodegradability and waterproofness. It can be usefully used for the purpose.

Claims (6)

(i) 5 to 25 weight percent polyvinyl alcohol resin, (ii) 30 to 60 weight percent primary filler selected from the group consisting of starch, chaff and mixtures thereof, and (iii) 30 to 40 weight percent water The paste composition for disposable biodegradable containers. The method of claim 1, The composition further comprises 0.1 to 20% by weight of the secondary filler and 0.1 to 1% by weight of the additive. The method of claim 2, The composition is characterized in that the secondary filler is selected from the group consisting of quicklime, talc, rosin and mixtures thereof. The method of claim 2, The additive is selected from the group consisting of ethylene glycol, glycerol, propylene glycol and mixtures thereof. A method for producing a disposable biodegradable container, comprising vacuum forming the resulting laminated sheet after the composition of any one of claims 1 to 4 is laminated with a biodegradable polyester film by compression molding. A resin composition for disposable biodegradable container comprising a polyvinyl alcohol resin and a primary filler selected from the group consisting of 1.2 to 12 parts by weight of starch, rice hulls and mixtures thereof, based on 1 part by weight of polyvinyl alcohol resin.