KR100992666B1 - Biodecompositive Soy Protein/Natural Fiber Composites - Google Patents

Abstract

The present invention relates to a biodegradable soy protein / natural fiber composites and a method for manufacturing the same, and more specifically, to a matrix resin containing soy protein having excellent biodegradation properties and natural fibers in the form of short fibers, woven or nonwoven fabrics. The present invention relates to a biodegradable soy protein / natural fiber composite and a method for producing the same. Soy protein / natural fiber composite of the present invention is not only mechanical properties such as tensile strength, bending strength, but also excellent biodegradability is very environmentally friendly.

Soy Protein, Biodegradable, Composites

Description

Biodegradable Soy Protein / Natural Fiber Composites

The present invention is a soy protein / natural fiber composite and a manufacturing method thereof, including a matrix resin and a natural fiber modified with soy protein as a plasticizer and a crosslinking agent, as well as excellent biodegradability, tensile strength, bending strength The present invention relates to a composite material suitable for use as a material for an exterior of an electronic component or an automobile interior material because of excellent mechanical properties.

Soy protein is a biodegradable natural polymer that is 100% degraded by microorganisms and enzymes in nature, and is commercially available as a powder obtained by crushing dried beans. Soy flour and soy protein aggregates depending on the degree of purification. It is classified as Concentrate, Soy Protein Isolate, and sold as a dietary supplement. Soy protein, a biodegradable polymer, is used as a raw material for health supplements in the form of powder, and some food companies use it as a raw material for snacks using injection methods. However, soy protein alone has a very poor mechanical strength and is fragile. Therefore, the basic research is actively used to apply to various fields of real life such as exterior of electronic products using natural polymers and interior materials for furniture and automobiles. It's going on.

In the case of glass fiber, it is almost permanently decomposed in the natural environment, and the polymer resin, which is a petroleum resource, is also not decomposed naturally, and because it causes air pollution by toxic gas or dust generated during incineration. Used polymer composite waste has become a big problem in terms of environmental pollution. Recently, natural fiber has a density of about 40% lower than glass fiber, so it is useful for developing lightweight materials, and because it is cheap, it is excellent in light weight and environmental friendliness. Natural fibers such as jute, flax, hemp, hemp, kenaf, and bamboo are widely used as reinforcements for polymer composites instead of glass fibers.

Some automobile companies have developed soy-based flexible foam materials and applied them as car seat interior foams, but they are limited to parts that contain less soybean and do not require much mechanical strength. Therefore, in order to apply to a structural agent that requires mechanical strength using it rather than using only biodegradability, it is required to develop a material that can be molded into a composite material.

Accordingly, the present inventors have conducted research to develop a biodegradable composite material suitable for use as an automobile interior material, and as a result, when the natural fiber is mixed with a matrix resin in which soy protein is modified with a plasticizer and a crosslinking agent, tensile strength and bending strength are greatly improved. It has been found that the present invention has been made. That is, the present invention has an object of the present invention to provide a biodegradable soy protein / natural fiber composite and a method for producing the same while having excellent mechanical properties.

Biodegradable soy protein / natural fiber composite of the present invention for solving the above problems is a matrix resin containing soy protein, plasticizer and crosslinking agent; And natural fiber; characterized in that it comprises a.

In addition, the present invention relates to a method for producing the composite material,

A first step of washing natural fibers;

A second step of preparing a matrix resin by mixing a soy protein aqueous solution of 4 to 20% concentration, a plasticizer and a crosslinking agent;

A third step of preparing a sheet by mixing the matrix resin and the natural fiber and then passing it through a pressing roll to dehydrate the sheet;

A fourth step of drying the sheet; And

And a fifth step of molding the dried sheet in a press or a vacuum chamber.

Such a composite material of the present invention is not only excellent in mechanical properties such as tensile strength and flexural strength, but also biodegradable, so it is very environmentally friendly, and is suitable for use as a material for exterior of electronic parts or automotive interior materials. In addition, the manufacturing method of the present invention can lower the manufacturing cost because it can utilize the existing equipment does not need to add a new equipment.

The biodegradable soy protein / natural fiber composite of the present invention and a method for preparing the same will be described in more detail as follows.

Biodegradable soy protein / natural fiber composites of the present invention include a matrix resin containing soy protein, a plasticizer and a crosslinking agent; And jute, flax, hemp, hemp, kenaf, ramie, ramie, sisal, henekin, pineapple leaf fiber, cotton fiber, coir ( coir), coconut fiber, bamboo fiber, banana fiber, rice straw or straw selected from the group consisting of two or more natural fibers; characterized in that it comprises a.

Soy protein, which is a component of the matrix resin, may be selected from the group consisting of soy flour (Soy Flour), soy protein concentrate (Soy Protein Concentrate), and soy protein isolate (Soy Protein Isolate) or two or more kinds. Preferably, soy protein aggregates are used alone.

The plasticizer, which is one of the components of the matrix resin, may use one or two or more selected from glycerol, propandiol, polyethylene glycol, and polyvinyl alcohol. Is a water-soluble, biodegradable low molecular weight or high molecular weight material, 1 to 60 parts by weight, more preferably 10 to 50 parts by weight based on 100 parts by weight of soy protein. Here, when the plasticizer is less than 1 part by weight based on 100 parts by weight of soy protein, a problem may occur that the molded soy protein is easily broken. When the amount is greater than 60 parts by weight, the unmixed plasticizer is broken or the strength is significantly reduced to maintain the shape. It is preferable to use the above range because problems may occur.

The crosslinking agent, which is another component of the matrix resin, improves physical properties through crosslinking of soy protein, and is selected from glutaldehyde, epichlorohydrin and glyoxal. Single or 2 or more types may be used, and 1 to 25 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of soy protein. Herein, when the crosslinking agent is less than 1 part by weight based on 100 parts by weight of soy protein, soybean protein may not be sufficiently crosslinked, and thus, mechanical properties may be deteriorated. It is preferable to use within the above range because a problem of rising may occur.

The natural fiber is used as a reinforcing material in the present invention, by using a mixture thereof can improve the mechanical properties. The natural fiber is any one selected from short fibers, woven fabrics and non-woven fabrics, it may be used single or two or more selected from these.

Biodegradable soy protein / natural fiber composite material of the present invention having the above-described components is characterized in that the matrix resin and the natural fiber is contained in a 1: 0.5 to 4 weight ratio.

Hereinafter will be described in detail with respect to the manufacturing method of the biodegradable soy protein / natural fiber composite of the present invention described above. Composite manufacturing method of the present invention

Jute, flax, hemp, hemp, kenaf, ramie, ramie, sisal, henekin, pineapple leaf fiber, cotton fiber, coir ), A first step of washing single or two or more natural fibers selected from coconut fiber, bamboo fiber, banana fiber, rice straw, and straw;

A second step of preparing a matrix resin by mixing an aqueous soy protein solution at a concentration of 4% to 20%, a plasticizer, and a crosslinking agent;

A third step of preparing a sheet by mixing the matrix resin and the natural fiber and then passing it through a pressing roll to dehydrate the sheet;

A fourth step of drying the sheet at 50 ° C to 90 ° C; And

And a fifth step of molding the dried sheet at a temperature of 100 ° C. to 140 ° C. and a pressure of 10 psi to 2000 psi in a press or a vacuum chamber.

The first step is a step of washing the natural fiber with a cleaning agent for 1 to 24 hours, when the washing time of the natural fiber is less than 1 hour, the cleaning effect is insignificant, and when more than 24 hours, the physical properties of the fiber is deteriorated do. The cleaning may be performed to remove lignin-containing substances such as pectin, low molecular weight wax and natural oils covering the fabric surface, or depending on the purpose, alkaline, bleaching, cyanoethylation, Acetylation, silane treatment, plasma treatment, ultraviolet treatment, grafting and the like can be used. The cleaning agent uses water, alcohols, and mixtures thereof, and after washing, may include preparing a sufficiently dry. In addition, the natural fibers may be in the form of short fibers, woven fabrics or non-woven fabrics, single or two or more selected from them.

In the second step, the soy protein aqueous solution may use water as a solvent, and the soy protein and water to be mixed so as to have a concentration of 4% to 20%, when the concentration of the soy protein solution is less than 4% excess water The present invention may be difficult to remove during molding, and may cause a problem of forming a dough without dissolving water in excess of 20%.

The plasticizer may use one or two or more selected from glycerol, propandiol, propanediol, polyethylene glycol, and polyvinyl alcohol, and 1 to 60 parts by weight of soy protein. Part by weight, more preferably 20 to 50 parts by weight can be used. The crosslinking agent may be selected from one or two or more selected from glutaldehyde, epichlorohydrin and glyoxal, and is 1 to 25 parts by weight, more preferably 100 parts by weight of soy protein. Preferably 5 to 20 parts by weight may be used, and the same problem as described above may occur when used outside the above range.

Next, in the third step, the matrix resin prepared in the second step and the natural fiber short fibers of the first step are mixed or the matrix resin is sprayed or impregnated into the natural fiber of a woven or nonwoven fabric, and then passed through a compression roll. It is a step of making a sheet by dehydration.

Next, the fourth step is a step of drying the sheet prepared in the third step at a temperature of 50 ° C ~ 90 ° C to the extent that the sheet does not flow. At this time, the drying method is not particularly limited, and a method generally used in the art may be used. Here, if the drying temperature is less than 50 ℃ may cause a problem that the drying time is increased, and when the drying temperature is exceeded above 90 ℃ may cause a problem that the film formation due to rapid drying and the drying time of the internal resin due to the formed film may increase the above temperature range It is preferable to dry inside.

Next, the fifth step is a step of forming the sheet dried in the fourth step under 100 ℃ ~ 140 ℃ temperature and 10 psi ~ 2000 psi pressure conditions may cause a problem that the molding time increases if the molding temperature is less than 100 ℃, When the temperature exceeds 140 ℃ may cause a problem of increased bubbles, if the molding pressure is less than 10 psi may cause a problem of insufficient flow of the resin, and when the temperature exceeds 2000 psi may cause a problem that the resin flows out a lot of the above temperature and Molding within the pressure range is preferred.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited thereto.

Example 1

Preparation of Biodegradable Soy Protein / Natural Fiber Composites

The nonwoven fabric of 400g / m ² nonwoven fabric was washed for 2 hours and then dried at 60 ° C. for 12 hours, and then stored at room temperature. 500 g of water and 50 g of soy protein isolate were mixed to prepare a 10% soy protein aqueous solution. Then, 25 g of glutinated polyvinyl alcohol was added to 100 parts by weight of soy protein isolate, and glutaldehyde, a crosslinking agent, was added. The matrix resin was prepared by mixing 2.5 g to 5 parts by weight. Thereafter, the soy protein aqueous solution having the same weight as the washed and dried sheep was impregnated in the sheep, and pressed to prepare a sheet to uniformly disperse the resin. After the sheet is dried to such an extent that it does not flow through the dryer. Resin-supplied sheet was cut to a size of about 20 × 20 cm, and two sheets were laminated and press-molded to completely remove moisture at a temperature of 130 ° C. and 1,000 psi for 100 minutes to prepare a biodegradable soy protein / natural fiber composite. It was.

Examples 2-4 and Comparative Examples 1-2

Example 1 was carried out in the same manner as in Example 1, Examples 2 to 4 and Comparative Examples 1 to 2 were carried out so that the composition of Table 1 is the same.

division matrix
Suzy Natural fiber
(Non-woven) Soy protein
Separators Polyvinyl alcohol
(Plasticizer) Glutaldehyde
(Bridge) Sheep Jute Example 1 50 g 25 g
(50 parts by weight) 2.5 g
(5 parts by weight) 40 g - Example 2 50 g 25 g
(50 parts by weight) 5 g
(10 parts by weight) 40 g - Example 3 50 g 25 g
(50 parts by weight) 10 g
(20 parts by weight) 40 g - Example 4 50 g 25 g
(50 parts by weight) 2.5 g
(5 parts by weight) - 40 g Comparative Example 1 50 g 25 g
(50 parts by weight) - 40 g - Comparative Example 2 50 g - 5 g
(10 parts by weight) 40 g - Soy protein isolate: Solae company USA, SPI
Polyvinyl Alcohol: Sigma-Aldrich, Molecular Weight 89,000 ~ 98,000
Glutaldehyde: Sigma-Aldrich, grade II
Sheepskin: Non-woven fabric with a surface density of 400g / m ²
Jute: non-woven fabric of the area density 400g / m ²

Experimental Example

Measurement of Properties of Soy Protein / Natural Fiber Composites

Experimental specimens were prepared by molding the composites prepared in Examples 1 to 4 and Comparative Examples 1 to 2 under conditions of a temperature of 130 ° C., a pressure of 1000 psi, and a molding time of 100 minutes using a 10-ton press.

The tensile test was conducted at room temperature at a rate of 50 mm / _min using a universal testing machine according to ASTM D638, and the tensile strength of the specimen of about 3 mm thickness was measured. Bending strength was performed at room temperature using a universal testing machine according to ASTM D790 at a rate of 20 mm / min. The bending strength of the specimen having a thickness of about 3 mm was measured and the results are shown in Table 2 below.

division Tensile strength (kgf / cm ² ) Bending strength (kgf / cm ² ) Example 1 2.136 3.96 Example 2 2.134 3.75 Example 3 2.152 2.66 Example 4 2.102 3.79 Comparative Example 1 1.520 2.73 Comparative Example 2 1.211 1.67

Looking at the experimental results of Table 2, and in Comparative Example 1 without the addition of a crosslinking agent at all can be confirmed that the tensile strength is significantly low, the bending strength increases as the amount of crosslinking agent added through the experimental results of Examples 1 to 4 You can see the increase. And in the case of Comparative Example 2 without using a plasticizer it can be seen that the tensile strength and bending strength is very low.

As described above, the soy protein / natural fiber composite of the present invention has excellent mechanical strength such as tensile strength and bending strength, and is manufactured in a form capable of molding and injection, so that it can be used as a material for exterior parts of automobile parts and automotive interior materials. Suitable.

Claims (6)

Matrix resins containing soy protein, plasticizer and crosslinking agent; And Single or two or more natural fibers selected from jute, flax, hemp, hemp, yam, ramie, sisal, henekin, pineapple leaf fiber, cotton fiber, coconut fiber, banana fiber, coir, rice straw and straw; It includes, The crosslinking agent is one or two or more selected from glutaldehyde, epichlorohydrin (epichlorohydrin) and glyoxal (glyoxal), 1 to 25 parts by weight based on 100 parts by weight of the soy protein Biodegradable soy protein / natural fiber composites characterized in that. The method of claim 1 The plasticizer is one or two or more selected from glycerol, propandiol, polyethylene glycol and polyvinyl alcohol, and 1 to 60 parts by weight based on 100 parts by weight of the soy protein. Biodegradable soy protein / natural fiber composite, characterized in that it comprises. delete The biodegradable soy protein / natural fiber composite according to claim 1, wherein the natural fiber comprises one or more species selected from short fibers, woven fabrics and nonwoven fabrics. [Claim 2] The biodegradable soy protein / natural fiber composite according to claim 1, wherein the soy protein comprises at least one selected from soybean powder, soybean protein aggregate and soybean protein isolate. To clean single or two or more natural fibers selected from jute, flax, hemp, hemp, yam, ramie, sisal, henekin, pineapple leaf fiber, cotton fiber, coconut fiber, banana fiber, coir, rice straw, and straw First step; A second step of preparing a matrix resin by mixing an aqueous soy protein solution at a concentration of 4% to 20%, a plasticizer, and a crosslinking agent; A third step of preparing a sheet by mixing the matrix resin and the natural fiber and then passing it through a pressing roll to dehydrate the sheet; A fourth step of drying the sheet at 50 ° C to 90 ° C; And A fifth step of molding the dried sheet at a temperature of 100 ° C. to 140 ° C. and a pressure of 10 psi to 2000 psi in a press or a vacuum chamber; Method of producing a biodegradable soy protein / natural fiber composite comprising a.