WO2023181504A1 - Biodegradable composite composition - Google Patents

Abstract

[Problem] To provide a starting material composition for plastic molded articles, the starting material composition minimizing the problems of soil, atmospheric air and marine pollution caused by burying or incineration of plastic molded articles, while reducing the production cost. [Solution] A biodegradable composite composition according to one embodiment contains 100 parts by weight of a biodegradable polymer matrix resin, 52-80 parts by weight of a powder of waste from coffee processing, and 14-20 parts by weight of a starch powder that is selected from the group consisting of rice flour, corn flour and a mixture thereof. The biodegradable polymer matrix resin contains 90 parts by weight of a polylactic acid (PLA) and 10 parts by weight of a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV).

Description

Biodegradable composite composition

The present invention relates to a biodegradable composite composition containing a bio-based filler, a synthetic filler, and other additives.

Technology related to degradable plastics is classified into three categories: photodegradation technology, biodegradation technology, and photobiodegradation technology. Furthermore, photolysis techniques are classified into two types: photosensitive functional group introduction type and photosensitive reagent addition type. The photosensitive functional group-introduced type was developed by a manufacturer that commercializes a copolymer of ethylene and carbon monoxide.

Additionally, the type that added a metal complex compound was the mainstream type that added a photosensitive reagent. However, these photodegradable products are expensive to manufacture, and when buried in the ground, sunlight is blocked and light energy cannot be absorbed, so they are not decomposed. Therefore, photodegradation technology alone cannot solve the plastic waste problem, and research into biodegradation technology continues.

Biodegradable plastics are composed of polymer products produced by microorganisms such as PLA (polylactic acid) and PHB (polyhydroxybutyrate), polymers synthesized from biochemical substances produced by microorganisms, and natural polymers such as chitin. has been done. However, these biodegradable plastics are expensive to manufacture and are not economically suitable, so biodegradable composite materials have been proposed that are made by adding coffee grounds or the like to ordinary plastics.

Japanese Patent Application Publication No. 2020-15887

Conventionally, there is a known technology that allows coffee grounds to be included as an option for biodegradable natural materials. However, there has been no practical biodegradable composite composition containing "coffee grounds" as an essential component.

Therefore, an object of the present invention is to provide a biodegradable material with excellent physical properties and safety in a simple process using biodegradable natural materials such as waste coffee grounds powder that can be easily obtained from the recycling process using coffee beans. By producing a biodegradable composite composition, we can minimize the problem of soil, air, and ocean pollution caused by burying or incineration when using biodegradable plastics, and further reduce manufacturing costs. It's about doing.

In order to solve the above-mentioned problems, the biodegradable composite composition according to the present invention contains 100 parts by weight of a biodegradable polymer matrix resin, 52 to 80 parts by weight of coffee grounds powder, rice flour, and corn flour. 14 to 20 parts by weight of starch powder selected from the group consisting of starch powder and mixtures thereof; the biodegradable polymeric matrix resin contains 90 parts by weight of polylactic acid (PLA); butyrate-co-3-hydroxyvalerate (PHBV) (10 parts by weight).

The present invention provides a biodegradable composite composition comprising 100 parts by weight of a mixture of PLA and PHBV and 5 to 200 parts by weight of a grain flour selected from the group consisting of coffee grounds flour and starch flour.

The biodegradable composite composition according to the present invention contains 0.1-5% glycerol as a biodegradation aid in order to improve the degradability of the composition and prevent deterioration of physical properties due to the addition of coffee grounds or starch powder. It is preferable to contain it in parts by weight. In addition, in order to improve the compatibility between coffee grounds powder and starch powder and the matrix resin, and simultaneously improve the physical properties and workability of the composition, 0.1 to 5 parts by weight of a reinforcing agent and 0 parts of a melt flowability improver are added. .1 to 5 parts by weight.

The present invention relates to a biodegradable composite composition. In addition to being able to be formed into various products with particularly good physical properties and safety, the material of the invention is made of natural materials, namely coffee grounds powder and starch powder. Since product waste produced from this composition is decomposed by natural microorganisms after a certain period of time, environmental problems such as soil, air, and ocean pollution caused by burying or incinerating product waste can be minimized. Can be done.

The present invention is characterized in that it consists of 100 parts by weight of a biopolymer (a non-toxic biodegradable plastic such as a biodegradable plastic naturally produced by bacteria), and 5 to 200 parts by weight of coffee grounds powder and starch powder. , relates to a biodegradable composite composition comprising coffee grounds powder.

The biodegradable composite composition according to the present invention can be produced in various forms such as injection molded products, sheet molded products, and blow molded products, and has excellent physical properties and product stability. Since the coffee grounds contained in the present composition are decomposed by natural microorganisms after a certain period of time, the efficiency of waste disposal of products manufactured using the present composition can be significantly improved. Therefore, the problems of soil pollution, air pollution, and ocean pollution caused by burying or incinerating conventional waste plastic molded products can be minimized.

The biodegradable composite composition according to the present invention will be explained in detail below. The biodegradable composite composition of the present invention contains 5 to 200 parts by weight, preferably 30 to 80 parts by weight of coffee grounds powder, based on 100 parts by weight of the biodegradable polymer matrix resin.

The matrix resin includes PLA (polylactic acid), PHB (polyhydroxybutyrate), PBAT (polybutylene adipate terephthalate), a biodegradable random copolymer, so-called PHBV (Poly (3-hydroxybutyrate-co-3-hydroxyvalerate), Biodegradable polymer resins such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and polybutylene succinate (PBS) can be used in consideration of product moldability.

The biodegradable composite composition according to the present invention contains a mixture of PLA and PBHV.

Among the terms used in the description of the present invention, coffee grounds powder and starch powder mean powder that has been dried to a moisture content of 5%.

Coffee grounds powder is a lignocellulosic biomass whose main components are elements necessary for life (C, H, O, N), and mainly cellulose (59.2-62.94 wt%) and hemicellulose (5-62.94 wt%). 10wt%) and lignin (19.8-26.5wt%). Additionally, these elements are present in the form of recoverable compounds such as essential oils, flavonoids, citric acid, and guaiacol chlorogenic acid. These compounds found in coffee grounds have the advantage of being compatible with PLA. In addition, this type of waste usually contains elements considered to be inorganic micronutrients, such as calcium, magnesium, and sodium, but the concentration thereof is generally less than 5.0% by dry weight.

Coffee grounds are known to slowly release nitrogen into the soil, so they can be used in the garden for composting and mulching. Dried coffee grounds contain large amounts of potassium, magnesium, and phosphorus. It is particularly liked by earthworms and acid-loving plants such as blueberries, but as the acid dissolves during use, the pH is generally neutral.

Used coffee grounds are attracting particular attention as a soil improvement material. Some coffee shops are working to prevent coffee bean waste, such as Starbucks' Ground for your Garden project, and Ground to Ground and Green Coffee Shop Scheme in Cambridgeshire, England. There are also community-sponsored initiatives such as

The starch flour is for example selected from the group consisting of rice flour, corn flour and mixtures thereof.

In this way, if a molded article is manufactured using a composite composition containing coffee grounds, it will be biodegraded by microorganisms after a certain period of time, minimizing the problem of soil, air, and water pollution. The efficiency of waste treatment can also be improved.

According to the composition of the present invention, when 0.1 to 5 parts by weight of glycerol as a biodegradation aid is added, not only biodegradability but also the reaction of the hydroxyl group of the hydrophilic glycerol with water improves the resin composition. This not only improves the physical properties of the molded product made from the product, but also prevents deterioration in physical properties due to the addition of coffee grounds powder or starch powder.

In addition, in order to improve both the general physical properties of the molded product and the compatibility of the biopolymer resin with coffee grounds and starch powder, 0.1 to 5 parts by weight of a reinforcing agent and 0.0 parts by weight of a melt flowability improver are added. 1 to 5 parts by weight may be added.

Reinforcers are used to increase the rigidity of molded products. An example of a reinforcing agent is an ethylene terpolymer composite such as ELVALOY PTW (Dow Corning Corp.) as a coupling agent. The coupling agent includes one selected from the group consisting of hydrogen peroxide compounds. Other latent components are included mainly to improve processability, such as melt flowability improvers and nucleating agents.

Flowability improvers are used to reduce friction in extrusion and injection molding processes. Flow improvers increase melt flow rates, lower processing temperatures, and improve productivity. Flow improvers can be used to reduce injection pressure and facilitate filling of thin-wall molded tools. The melt fluidity improver includes at least one selected from the group consisting of calcium stearate, zinc stearate, barium stearate, aluminum stearate, magnesium stearate, paraffin wax, and polyethylene wax. An example of a melt flow enhancer is AP00157 EU Flow Enhancer (CRPP) MB (Tosaf Group, registered trademark).

An example of a nucleating agent is PLA masterbatch CM-L01 (Polyvel Inc., registered trademark). Other additives such as ultraviolet/thermal stabilizers and colorants may also be added.

The above biodegradable composite composition can be used for injection molded products, sheet molded products, and blow molded products. For example, a biodegradable polymer resin, coffee grounds powder, starch powder, glycerol, a chemical strengthener, and a melt fluidity improver are mixed in a predetermined ratio, melted, and then extruded using a twin-screw extruder. It is granulated using a pelletizer, and injection molded products and sheet molded products are manufactured using an injection molding machine or sheet casting extruder. At this time, the following formulation parameters were maintained:

 
ノズル出口での溶融温度：１６５度
回転数：１２５rpm
スループット：４０kg/hr
脱ガス：真空ゾーン７

Melting temperature at nozzle exit: 165 degrees Rotation speed: 125 rpm
Throughput: 40kg/hr
Degassing: Vacuum zone 7

The mixture was melted and granulated using a GER120 twin-screw extruder (screw diameter 30 mm, L/D=45).
For this purpose, the following injection process parameters were set.

 
回転数：５２rpm
環状空間：１．４５mm
ノズル出口での溶融温度：１７０度

Rotation speed: 52rpm
Annular space: 1.45mm
Melting temperature at nozzle exit: 170 degrees

[Example]
Hereinafter, details of the present invention with reference to embodiments will be explained. However, the embodiments of the present invention can be modified in various ways, and should not be understood as being limited to the embodiments described below. Rather, these embodiments are provided so that this disclosure will be more fully understood and understood by those skilled in the art.

[First example]
100 parts by weight of biodegradable polymer matrix resin (melt index: 18) made by mixing PLA with PHBV in a ratio of 90:10, coffee grounds powder and starch powder in a ratio of 80:20. 100 parts by weight of glycerol, 5 parts by weight of glycerol, 1 part by weight of reinforcing agent, and 1 part by weight of melt flowability improver, melted at 170°C for 3 to 4 minutes while mixing, and extruded at 170°C. Formed into pellets.

[2nd to 9th Examples]
A composition was produced in the same manner as in Example 1, except that the components used and their contents were as shown in Table 3 below.
In Table 3 below, the unit of component content is parts by weight.

 
 

 
 

The biodegradable composite composition according to the above embodiment was injected using an injection molding machine under conditions of 170 to 175°C and 500 to 600 psi to obtain a sample with a thickness of 3.26 mm. The tensile strength, tensile elongation, and shape of this sample were measured and the results are shown in Table 4 below.

Taking into consideration the color of the appearance and the degree of dirt, the shape was evaluated using the following criteria, dividing it into three levels: "good," "fair," and "poor." In addition, we prepared chips and experimental samples with a size of 100 x 100 x 5 mm, and after spraying water on the surfaces of the chips and experimental samples, we considered the degree of decomposition based on the following criteria and determined that the biodegradability was good. The evaluation was divided into three levels: , normal, and poor.

(1) Criteria for estimating shape Good: The composition can be molded into a sample, and there is no deformation due to the inclusion of additives.
Normal: The composition can be molded into a sample, but there may be some deformation due to the inclusion of additives, etc.
Defective: The molding of the composition into the sample is defective.
(2) Criteria for estimating biodegradability Good: 50% or more of the entire sample is decomposed.
Normal: 30% or more of the entire sample is decomposed.
Poor: Less than 10% of the entire sample is degraded.

Referring to Table 4, it can be clearly understood that the samples produced using the biodegradable composite compositions according to the examples have good physical properties such as shape, tensile strength, and tensile elongation, and can be used for various products. Furthermore, since the composition according to the example exhibits excellent biodegradability, the composition can minimize environmental problems such as soil pollution, air pollution, and marine pollution caused by burying or incinerating product waste. It is a thing.

As described above, the biodegradable composite composition according to the present invention can further simplify the manufacturing process of biodegradable products and make it highly cost-effective. In particular, coffee grounds powder and starch powder showed better compatibility with PLA-PHBV matrix resin and had better stability against discoloration and stability against water absorption, so they were formulated and manufactured with biopolymer resin. Molded articles of the composition can be used more usefully than those of other types of grains.

Furthermore, since the composition according to the present invention is decomposed by natural microorganisms after a certain period of time, environmental problems such as soil, air, and ocean pollution caused by burying or incinerating product waste can be minimized.

Claims (7)

100 parts by weight of biodegradable polymer matrix resin,
52 to 80 parts by weight of coffee grounds powder,
14 to 20 parts by weight of starch flour selected from the group consisting of rice flour, corn flour and mixtures thereof;
including;
The biodegradable polymer matrix resin is
90 parts by weight of polylactic acid (PLA),
A biodegradable composite composition comprising 10 parts by weight of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The biodegradable composite composition according to claim 1, further comprising 3 to 5 parts by weight of glycerol. 3 to 5 parts by weight of an ethylene terpolymer composite as a reinforcing agent,
3 to 5 parts by weight of a melt flowability improver,
The biodegradable composite composition according to claim 1 or 2, further comprising: 4. The melt fluidity improver according to claim 3, wherein the melt flowability improver includes at least one selected from the group consisting of calcium stearate, zinc stearate, barium stearate, aluminum stearate, magnesium stearate, paraffin wax, and polyethylene wax. Biodegradable composite composition. The biodegradable composite composition according to claim 1, wherein the coffee grounds powder and the starch powder are contained in a weight ratio of 4:1. Containing 52 parts by weight of the coffee grounds powder,
The biodegradable composite composition according to claim 1, comprising 14 parts by weight of the starch powder. Containing 80 parts by weight of the coffee grounds powder,
The biodegradable composite composition according to claim 1, comprising 20 parts by weight of the starch powder.