TWI582161B - Producing method of a biodegradable polylactic acid based composite - Google Patents

Description

Method for producing biodegradable polylactic acid composite material

A biodegradable material, in particular a polylactic acid biodegradable composite.

At present, disposable food tableware is still based on general-purpose plastics, such as polyethylene (Polyethylene, PE), polypropylene (PP), polystyrene (PS), melamine or styrofoam. Although this kind of general-purpose plastic has the advantage of low cost, its biodegradability has a great harm to the global environment, and the toxic substances produced by combustion will affect the health of future generations.

As the end of petroleum energy is approaching, alternative plastics are a trend. Among them, Poly Lactic Acid (PLA), known as "bioplastics", is a mainstream development material using plastic materials derived from biological raw materials. However, although polylactic acid (PLA) has the advantages of biodegradability, it has insufficient heat resistance and mechanical strength, and is easily deformed by heat. It is difficult to replace the general petrochemical plastic. If it is used in disposable food and tableware, it is more restrictive.

In order to solve the disadvantages that the polylactic acid (PLA) material cannot have certain heat resistance or mechanical strength, the present invention is a method for producing a biodegradable polylactic acid composite material, which comprises the steps of: using a modified starch and a polymerization. Ester oil produces a natural fermentation reaction to form a change Starch; the above-mentioned modified starch and a polylactic acid are co-melted and kneaded; a toughening agent, a crystal nucleating agent and a heat-resistant modifier are melted and kneaded together in the modified starch and the polylactic acid; The modified starch, the polylactic acid, the toughening agent, the crystal nucleating agent and the heat-resistant modifier are extruded from a kneader in water to cool down and further dehydrated to form a polylactic acid composite masterbatch, wherein: The reaction temperature of the natural fermentation reaction is from a normal temperature of 25 ° C to 30 ° C until the temperature is between 60 ° C and 65 ° C; the kneading temperature is between 170 ° C and 270 ° C; and the toughening agent, the crystal nucleating agent And the heat-resistant modifier is added when the melting and kneading temperature reaches equilibrium.

Among them, a kneading machine is used for melt kneading.

Wherein, the toughening agent, the crystal nucleating agent and the heat-resistant modifying agent are fed from the side end opening of the kneading machine.

Among them, the polylactic acid composite masterbatch is further processed into a container having a heat-resistant temperature of 120 ° C.

The present invention further provides a biodegradable polylactic acid composite material comprising 50% to 90% by weight of polylactic acid uniformly melt-kneaded, 0.1% to 40% by weight of modified starch, and 0.5% to 35% by weight of polyester oil. The toughener is 0 wt% to 40 wt%, the crystal nucleating agent is 0 wt% to 5 wt%, and the heat resistant modifier is 0 wt% to 50 wt%, and the biodegradable polylactic acid composite material has a heat resistance temperature of 120 °C.

Wherein, the modified starch is acetic acid starch, acetylated adipic acid starch, hydroxypropyl starch, hydroxypropyl phosphate diamyl starch, octenyl succinate starch or acetylated oxidized starch; the polyester oil Contains palm oil, castor oil or coconut oil; the toughening agent is a polyol polyester resin, a vinyl resin, a glycidyl methacrylate resin, polyethylene terephthalate, polybutylene terephthalate , styrene-maleic anhydride copolymer resin, thermoplastic polyester elastomer, styrene-ethylene-butyl An styrene elastomer or a nylon 12 elastomer; the crystal nucleating agent is a calcium salt of montanic acid, a sodium salt of montan or a talc; and the heat-resistant modifier is a styrene-phenyl malayan Amine copolymer.

The present invention further provides a medical bioabsorbable suture comprising 50% to 90% by weight of polylactic acid uniformly melt-kneaded, 0.1% to 40% by weight of modified starch, and 0.5% to 35% by weight of polyester oil. The toughener is 0 wt% to 40 wt%, the crystal nucleating agent is 0 wt% to 5 wt%, and the heat resistant modifier is 0 wt% to 50 wt%.

Wherein, the modified starch is acetic acid starch, acetylated adipic acid starch, hydroxypropyl starch, hydroxypropyl phosphate diamyl starch, octenyl succinate starch or acetylated oxidized starch; the polyester oil Contains palm oil, castor oil or coconut oil; the toughening agent is a polyol polyester resin, a vinyl resin, a glycidyl methacrylate resin, polyethylene terephthalate, polybutylene terephthalate , styrene-maleic anhydride copolymer resin, thermoplastic polyester elastomer, styrene-ethylene-butylene-styrene elastomer or nylon 12 elastomer; the crystal nucleating agent is calcium salt of montanic acid, montanic acid a sodium salt or talc; and the heat-resistant modifier is a styrene-phenyl maleimide copolymer.

According to the above description, the present invention has the following advantages:

1. The invention improves the structural strength and toughness of the material by adding the modified starch after fermentation, and improves the heat-resistant temperature of the invention to 120 ° C. When used in food tableware or baby bottle, it can withstand high temperature and does not release toxic substances. , use safe and secure.

2. When the invention recovers and burns, the main additives, polylactic acid and starch, are biologically derived materials, and the combustion does not produce toxic substances such as dioxin, and the main combustion product is water gas, which does not cause air pollution, and the coal slag generated after combustion is mainly The ingredients are all organic substances, and can be further used as fertilizer for plants and crops.

3. It can be decomposed after recycling of general-purpose plastics and burned to produce environmentally harmful substances. Disadvantages, the polylactic acid composite material of the present invention can replace the utility of existing general-purpose plastics to achieve environmental protection and reduce carbon footprint.

1 is a flow chart of a manufacturing process in accordance with a preferred embodiment of the present invention.

A method for producing a biodegradable polylactic acid composite material, the steps comprising:

Step 1: Using a modified starch and a polyester oil to produce a natural fermentation reaction to form a modified starch. The reaction temperature and the reaction time of the natural fermentation reaction are judged by the increase in the temperature of the fermentation reaction, and the modified starch and the polyester oil are mixed from room temperature, and are completed between 60 ° C and 65 ° C. The purpose of the fermentation reaction is to increase the toughness and strength of the modified starch, and the structure of the composite material of the present invention can be enhanced and the toughness is increased in the subsequent processing to achieve high temperature resistance.

Step 2: The above modified starch is co-melted and kneaded together with a polylactic acid. The melt kneading system is melt-kneaded at a temperature of 170 ° C to 270 ° C using a kneading machine. Further, a toughening agent, a crystal nucleating agent and a heat-resistant modifying agent may be added to the side end opening of the kneading machine to melt and knead together in the modified starch and the polylactic acid.

The reason for the above-mentioned opening at the side end of the kneading agent is that the side opening of the general kneading machine is mostly disposed in the middle of the kneading machine, because the temperature of the original feeding end of the kneading machine is lower than that of the middle of the kneading machine or the original The mixing temperature at the feed end is continuously changed due to the feeding factor. If the toughening agent, the crystal nucleating agent and the heat-resistant modifier are fed at the original feed end, the mixing may not be uniform due to insufficient or uneven temperature. Therefore, the temperature in the middle of the kneading machine is higher (the mixing temperature reaches the equilibrium) The toughening agent, the crystal nucleating agent and the heat-resistant modifier can promote the mixing more uniformly, and the amount of the toughening agent, the crystal nucleating agent and the heat-resistant modifier is increased relative to the modified starch and the polylactic acid. Less, so adding from the middle of the mixing machine will not cause drastic changes in the mixing temperature.

Step 3: the modified starch, the polylactic acid, the toughening agent, the crystal nucleating agent and the heat-resistant modifier are extruded from the kneading machine in water to cool down and further remove water to form a polylactic acid composite. Material masterbatch. The toughening agent, the crystal nucleating agent and the heat resistant modifying agent further assist in the toughening, heat resistance and crystallization characteristics of the polylactic acid composite material of the present invention.

Step 4: The polylactic acid composite masterbatch is further processed into a shape. Generally, the polylactic acid material has a heat resistance temperature of about 60 ° C, and if it exceeds this temperature, deformation occurs. The invention improves the structural strength and toughness of the material by adding the modified starch after fermentation, and can improve the heat resistance temperature up to 120 °C. In addition to the manufacture of articles which generally do not require heat resistance, such as stationery, electronic article casings, disposable medical appliances, medical bioabsorbable sutures or baby products, the present invention can be used for heat resistance up to 120 ° C, and can be applied to foods. The tableware or the baby bottle and the like which are required to hold the high-temperature food, the polylactic acid composite material of the invention can withstand high temperature and does not release toxic substances, and is safe to use. When the invention recovers and burns, the main additives, polylactic acid and starch, are biologically derived materials, and the combustion does not produce toxic substances such as dioxin, and the main combustion product is moisture, which does not cause air pollution, and the main components of the coal gangue produced after combustion are For organic matter, it can be further used as a fertilizer for plants and crops.

The modified starch is added in an amount of about 0.1 to 40% by weight of the polylactic acid composite, and the polyester oil is added in an amount of about 0.5 to 35 wt% of the polylactic acid composite. The modified starch may be Starch acetate. , Acetylated distrach adipate, Hydroxypropyl starch, Hydroxypropyl phosphate (Hydroxypropyl distarch phosphate), Starch sodium octenyl succinate or Acetylated oxidized starch, the polyester oil comprising palm oil, castor oil or coconut oil. The toughening agent is added in an amount of about 0-40% by weight of the polylactic acid composite material, and the toughening agent may be a polyester polyol, a vinyl resin, or a methacrylic acid shrinkage. Glycol methanlacrylate acrylic resin, polyethylene terephthalate, polybutylene terephthalate, styrene-maleic anhydride copolymer (Styrene-Maleic Anhydride Copolymer) Resin), Thermoplastic elastomer ester resin, Styrene ethylene/butylene styrene elastomer or Polyamide 12 elastomer. The nucleating agent is added in an amount of about 0 to 5 wt% of the polylactic acid composite material, and the crystal nucleating agent may be Calcium soap of montanic acids or sodium soap of montanic acids. Or talcum powder (Talc). The heat-resistant modifier is added in an amount of about 0 to 50% by weight of the polylactic acid composite, and the heat-resistant modifier may be a Styrene-phenyl maleimide copolymer.

A first preferred embodiment of the invention:

Polylactic acid-----------------------65wt%

Palm oil-----------------------0.5~30wt%

Octenyl succinate starch----------------------10wt%

Thermoplastic Polyester Elastomer --------------------- 15wt%

Styrene-phenylmaleimide copolymer-----------------------10wt%

Montan acid calcium salt-----------------------0.5phr

The octene succinate starch and the polyester oil are uniformly mixed for natural fermentation reaction, and the reaction temperature of the natural fermentation reaction reaches 60 ° C to 65 ° C to form a modified lake. The modified starch is added to the kneading machine and melted and mixed with the polylactic acid. The mixing temperature is about 170 ° C ~ 270 ° C. The kneading at the same time from the side end of the mixing machine will be a thermoplastic polyester elastomer, styrene-phenyl horse. The quinone imine copolymer and the calcium salt of montanic acid are added together for melting and kneading. After the mixing is completed, all the materials are extruded from the kneading machine into the cooling water, dehydrated by water to form a polylactic acid composite masterbatch, and the polylactic acid composite masterbatch is further granulated and formed.

A second preferred embodiment of the present invention:

The acetylated adipic acid starch and the polyester oil are uniformly mixed for natural fermentation reaction, and the reaction temperature of the natural fermentation reaction reaches 60 ° C to 65 ° C to form a modified starch. The modified starch is added to the kneading machine and melted and mixed with the polylactic acid. The mixing temperature is about 170 ° C ~ 270 ° C, and the nylon 12 elastomer and styrene-maleic anhydride copolymer resin are mixed at the side of the mixing machine. The styrene-phenyl maleimide copolymer and the calcium salt of montanic acid are added together for melting and kneading. After the mixing is completed, all the materials are extruded from the kneading machine into the cooling water, dehydrated by water to form a polylactic acid composite masterbatch, and the polylactic acid composite masterbatch is further granulated and formed.

As can be seen from the above description, the present invention has the following advantages:

1. The invention improves the structural strength and toughness of the material by adding the modified starch after fermentation, and improves the heat-resistant temperature of the invention to 120 ° C. When used in food tableware or baby bottle, it can withstand high temperature and does not release toxic substances. , use safe and secure.

2. When the invention recovers and burns, the main additives, polylactic acid and starch, are biologically derived materials, and the combustion does not produce toxic substances such as dioxin, and the main combustion product is water gas, which does not cause air pollution, and the coal slag generated after combustion is mainly The ingredients are all organic substances, and can be further used as fertilizer for plants and crops.

3. The polylactic acid composite material of the present invention can replace the existing general-purpose plastics to achieve environmental protection and reduce the carbon footprint by having various disadvantages such as the inability to decompose after the recovery of the general-purpose plastic and the pollution of the environment.

Claims (4)

A method for producing a biodegradable polylactic acid composite material, comprising the steps of: using a modified starch and a polyester oil to produce a natural fermentation reaction to form a modified starch; and melting the modified starch and a polylactic acid together; Mixing; adding a toughening agent, a nucleating agent, and a heat-resistant modifying agent to melt and knead together in the modified starch and the polylactic acid; and the modified starch, the polylactic acid, the toughening agent, The crystal nucleating agent and the heat-resistant modifier are extruded from water in a kneading machine to cool down and further remove water and dehumidify to form a polylactic acid composite masterbatch, wherein: the reaction temperature of the natural fermentation reaction starts at a normal temperature of 25 ° C to 30 ° C. Ending when the temperature is between 60 ° C and 65 ° C; the kneading temperature is between 170 ° C and 270 ° C; and the toughening agent, the crystal nucleating agent and the heat-resistant modifier are at equilibrium when the melting and kneading temperature is reached. Add to. The method for producing a biodegradable polylactic acid composite material according to claim 1 is melt-kneaded by a kneading machine. The method for producing a biodegradable polylactic acid composite material according to claim 2, wherein the toughening agent, the crystal nucleating agent, and the heat-resistant modifying agent are fed from a side end opening of the kneading machine. The method for producing a biodegradable polylactic acid composite material according to claim 1 or 2 or 3, wherein the polylactic acid composite material masterbatch is further processed into a container having a heat-resistant temperature of 120 °C.