CN107236235A - A kind of method that foamed plastic is produced with modified starch - Google Patents

Abstract

The invention relates to the technical field of polymer materials, in particular to a method for producing foamed plastics with modified starch. The present invention is achieved through the following technical scheme: firstly carry out graft copolymerization reaction of starch and methyl acrylate to obtain modified starch, adjust the water content of modified starch and carry out granulation, polysuccinate-butylene glycol, etc. After the biodegradable polyester is dried, it is mixed with the aforementioned modified starch pellets in proportion, and put into an extruder for physical foaming to obtain a biodegradable foamed plastic product. The foamed plastic prepared by the method is biodegradable, has good processing and use performance, low production cost, great competitive advantage and broad market prospect.

Description

A method of producing foamed plastics with modified starch

technical field

The invention relates to the technical field of polymer materials, in particular to a method for producing foamed plastics with modified starch.

Background technique

The extensive use of petroleum-based foam plastics in daily life has not only brought convenience to human beings, but also caused extremely serious negative impacts on the environment. The discarded foam plastics are difficult to degrade and contain a large amount of toxic substances, which not only imposes a very serious burden on the land, but also on the ecological environment such as the ocean. Therefore, in recent years, people have been researching and developing various bio-based foamed plastics that can be degraded and will not burden the natural environment. At present, there are many relatively mature technologies for producing foamed plastic products with polylactic acid materials. For example, a biodegradable polylactic acid foam preparation method whose publication number is CN1544525A; a polylactic acid foam material and a preparation method thereof whose publication number is CN103642185A, and the like. Although the foamed plastics produced by the aforementioned technology can be biodegradable, due to price reasons, it is more difficult to popularize the foamed plastics made by the above-mentioned method. In order to reduce costs, there are also many technologies that use starch as a raw material for foamed plastics to produce foamed plastics. CN01132749.9 discloses a method for preparing starch-based biodegradable foamed plastics. In this method, the raw materials of foamed plastics include starch acrylate, styrene, methyl acrylate, butyl acrylate, and auxiliary agents; CN200610069806.1 discloses a method using The preparation method of EVA, PE and starch composite foaming material, this method is to take EVA, PE as main raw material, take starch and inorganic powder as auxiliary material, and be equipped with glycerin, cross-linking agent, foaming agent AC and surface modification agent to prepare foam. Although the above technology utilizes starch as the raw material of foamed plastics, a relatively large amount of petroleum-based plastics is added in the technology, which seriously affects the degradation performance of the produced foamed plastics.

Contents of the invention

In order to make up for the defects of the above technical solutions, the present invention provides a new method for producing biodegradable foamed plastics with modified starch.

The present invention is achieved through the following technical solutions:

A method for producing biodegradable foamed plastics by grafting modified starch with methyl acrylate, is characterized in that it has the following steps:

A. starch and methyl acrylate are carried out graft copolymerization reaction, make modified starch, and methyl acrylate content is not more than 30wt%;

B. adjust the water content of the modified starch so that the water content is 15-30wt%;

C. the modified starch that B step obtains is extruded granulation by extruder;

D. drying the granules obtained in step C until the water content does not exceed 3wt%, to obtain Granule 1;

E. select fully biodegradable resin pellets and dry them to obtain pellets 2;

F. Mix granule 1 and granule 2 in proportion and put them into the extruder hopper for physical foaming to obtain biodegradable foamed plastics.

Preferably, in the step C, the die temperature of the extruder does not exceed 60°C.

Preferably, the extruder is provided with an exhaust port, and the temperature in the heating zone of the extruder does not exceed 120°C.

Preferably, in step D, the drying temperature is not more than 60°C.

Preferably, in the step E, the fully biodegradable resin is polyterephthalic acid-adipate-butylene glycol, polysuccinate-butylene glycol, polysuccinate-adipate- One or a combination of butylene glycol, polyterephthalic acid-succinic acid-butylene glycol.

Preferably, in the step F, the weight percentage of grain two is 10--50wt%.

Preferably, in the step F, maleic anhydride and benzoyl peroxide are also added.

Preferably, the maleic anhydride accounts for 1-3% by weight, and the benzoyl peroxide accounts for 0.1-0.5% by weight.

Preferably, in the step F, the physical foaming agent is butane or n-pentane.

Preferably, in the step F, the physical blowing agent is nitrogen or carbon dioxide.

The beneficial effects of the present invention are: the present invention provides a method for producing biodegradable foamed plastics by grafting modified starch with methyl acrylate. Biodegradable resin for processing and foaming. The foamed plastics produced by the invention can be biodegraded because the main component is starch, and the added resin is also biodegradable. Secondly, the present invention uses polybutylene succinate and other materials in the field of foamed plastics; finally, because the foamed plastics involved in this invention use a relatively large amount of low-cost starch, the product has a very good price Competitive and broad market prospects.

detailed description

The present invention will be further described in detail through specific embodiments below, but these embodiments are only for illustration and do not limit the scope of the present invention.

Embodiment one

Put 9,000g of cornstarch into a stirred reactor containing 20,000g of deionized water, stir evenly, add 1,000g of methyl acrylate, then add the catalyst cerium ammonium nitrate into the stirred reactor, and continue stirring until the reaction takes 2-3 hours. The reaction product is taken out from the stirring reaction kettle and put into a centrifuge to remove water to obtain the modified starch, and the modified starch is put into a drier for drying, and the dried water content reaches 20wt%. Then the modified starch with the water content is granulated through a direct suction type single-screw extruder. The speed of the extruder is 20r/min, the length-to-diameter ratio is 40, and the temperature is set to 90°C in the feeding section, 115°C in the first compression section, 115°C in the first homogenization section, 100°C in the exhaust section, and 120°C in the second compression section. , The second homogenization section 110°C.

Put the obtained granules into a dryer, set the drying temperature to 60° C., and dry for 8 hours to obtain Granule 1.

Put the polybutylene succinate into a dryer at a drying temperature of 80°C for 12 hours to obtain Granule 2.

Get the grain one of 60 weight parts and the grain two of 40 weight parts and mix and put into foaming machine (what this embodiment selects is pearl cotton foaming machine, and wherein extruder screw length-to-diameter ratio is 55, and screw speed is 5- 50r/min, the heating temperature is set to 90°C, 110°C, 130°C, 130°C, 120°C, the foaming agent is butane) hopper, at the same time, take 1 weight part of maleic anhydride and 0.1 weight part of Benzoyl oxide is mixed and added to the extruder evenly in proportion. The above-mentioned materials are heated with the screw rotation and the heating device in the extruder. After mixing, melting, homogenization, butane gas injection, mixing and homogenization, extrusion, Cooling molding, sizing and cutting, finished products and other processes to obtain biodegradable foamed plastic products.

Example two

Put 8,000g of cornstarch into a stirred reactor filled with 20,000g of deionized water, stir evenly, add 2,000g of methyl acrylate, then add the catalyst cerium ammonium nitrate into the stirred reactor, and continue stirring until the reaction takes 2-3 hours. The reaction product is taken out from the stirring reaction kettle and put into a centrifuge to remove water to obtain the modified starch, and the modified starch is put into a drier to dry, and the dried water content reaches 25wt%. Then the modified starch with the water content is granulated through a direct suction type single-screw extruder. The speed of the extruder is 20r/min, the length-to-diameter ratio is 40, and the temperature is set to 90°C in the feeding section, 115°C in the first compression section, 115°C in the first homogenization section, 100°C in the exhaust section, and 120°C in the second compression section. , The second homogenization section 110°C.

Put the obtained granules into a dryer, set the drying temperature to 60° C., and dry for 12 hours to obtain Granule 1.

Put the polybutylene succinate into a dryer at a drying temperature of 90°C for 10 hours to obtain Granule 2.

Get 80 parts by weight of grain one and grain two of 20 weight parts and mix them evenly into a foaming machine (this embodiment selects an pearl cotton foaming machine, wherein the extruder screw length-to-diameter ratio is 55, and the screw speed is 5- 50r/min, the heating temperature is set to 90°C, 110°C, 130°C, 130°C, 120°C, the foaming agent is butane) hopper, at the same time, take 2 parts by weight of maleic anhydride and 0.3 parts by weight of Benzoyl oxide is mixed and added to the extruder evenly in proportion. The above-mentioned materials are heated with the screw rotation and the heating device in the extruder. After mixing, melting, homogenization, butane gas injection, mixing and homogenization, extrusion, Cooling molding, sizing and cutting, finished products and other processes to obtain biodegradable foamed plastic products.

Embodiment three

Put 9,250g of cornstarch into a stirred reactor filled with 20,000g of deionized water, stir evenly, add 750g of methyl acrylate, then add the catalyst cerium ammonium nitrate into the stirred reactor, and continue stirring until the reaction takes 2-3 hours. The reaction product is taken out from the stirring reaction kettle and put into a centrifuge to remove water to obtain the modified starch, and the modified starch is put into a desiccator for drying, and the dried water content reaches 16wt%. Then the modified starch with the water content is granulated through a direct suction type single-screw extruder. The speed of the extruder is 20r/min, the length-to-diameter ratio is 40, and the temperature is set to 90°C in the feeding section, 115°C in the first compression section, 115°C in the first homogenization section, 100°C in the exhaust section, and 120°C in the second compression section. , The second homogenization section 110°C.

Put the obtained granules into a dryer, set the drying temperature to 55° C., and dry for 12 hours to obtain Granule 1.

Put the polybutylene succinate into a dryer at a drying temperature of 90°C for 10 hours to obtain Granule 2.

Get the grain one of 55 weight parts and the grain two of 45 weight parts and mix and put into foaming machine (what this embodiment selects is pearl cotton foaming machine, and wherein extruder screw length-to-diameter ratio is 55, and screw speed is 5- 50r/min, the heating temperature is set to 90°C, 110°C, 130°C, 130°C, 120°C, the foaming agent is butane) hopper, at the same time, take 1.5 parts by weight of maleic anhydride and 0.2 parts by weight of over Benzoyl oxide is mixed and added to the extruder evenly in proportion. The above-mentioned materials are heated with the screw rotation and the heating device in the extruder. After mixing, melting, homogenization, butane gas injection, mixing and homogenization, extrusion, Cooling molding, sizing and cutting, finished products and other processes to obtain biodegradable foamed plastic products.

Embodiment four

Put 7,300g of cornstarch into a stirred reactor filled with 20,000g of deionized water, stir evenly, add 2,700g of methyl acrylate, then add the catalyst ceric ammonium nitrate into the stirred reactor, and continue stirring until the reaction takes 2-3 hours. The reaction product is taken out from the stirring reaction kettle and put into a centrifuge to remove water to obtain the modified starch, and the modified starch is put into a drier to dry, and the dried water content reaches 30wt%. Then the modified starch with the water content is granulated through a direct suction type single-screw extruder. The speed of the extruder is 20r/min, the length-to-diameter ratio is 40, and the temperature is set to 90°C in the feeding section, 115°C in the first compression section, 115°C in the first homogenization section, 100°C in the exhaust section, and 120°C in the second compression section. , The second homogenization section 110°C.

Put the obtained granules into a dryer, set the drying temperature to 60° C., and dry for 24 hours to obtain Granule 1.

Put the polybutylene succinate into a dryer at a drying temperature of 70°C for 15 hours to obtain Granule 2.

Get the grain one of 90 weight parts and the grain two of 10 weight parts and mix and put into foaming machine (what this embodiment selects is pearl cotton foaming machine, and wherein extruder screw length-to-diameter ratio is 55, and screw speed is 5- 50r/min, the heating temperature is set to 90°C, 110°C, 130°C, 130°C, 120°C, the blowing agent is butane) hopper, at the same time, take 3 parts by weight of maleic anhydride and 0.5 parts by weight of Benzoyl oxide is mixed and added to the extruder evenly in proportion. The above-mentioned materials are heated with the screw rotation and the heating device in the extruder. After mixing, melting, homogenization, butane gas injection, mixing and homogenization, extrusion, Cooling molding, sizing and cutting, finished products and other processes to obtain biodegradable foamed plastic products.

Embodiment five

In this example, microcellular foams are produced by continuous extrusion molding, and the blowing agent is carbon dioxide.

Put 8,000g of cornstarch into a stirred reactor filled with 20,000g of deionized water, stir evenly, add 2,000g of methyl acrylate, then add the catalyst cerium ammonium nitrate into the stirred reactor, and continue stirring until the reaction takes 2-3 hours. The reaction product is taken out from the stirring reaction kettle and put into a centrifuge to remove water to obtain the modified starch, and the modified starch is put into a drier to dry, and the dry water content is 25wt%. Then the modified starch with the water content is granulated through a direct suction type single-screw extruder. The speed of the extruder is 20r/min, the length-to-diameter ratio is 40, and the temperature is set to 90°C in the feeding section, 115°C in the first compression section, 115°C in the first homogenization section, 100°C in the exhaust section, and 120°C in the second compression section. , The second homogenization section 110°C.

Put the obtained granules into a drier, set the drying temperature to 60° C., and dry for 10 hours to obtain Granule 1.

Put the polybutylene succinate into a dryer at a drying temperature of 90°C for 10 hours to obtain Granule 2.

The extruder is specially used for microcellular foaming. Compared with ordinary extruders, in the screw cavity, the rear of the screw is connected to a static mixer, and the static mixer is connected to a quick release nozzle. The specific foaming process is: get 70 parts by weight of granules one and 30 parts by weight of granules two and mix them evenly into the hopper of the extruder. At the same time, take 2 parts by weight of maleic anhydride and 0.5 parts by weight of benzyl peroxide After the acyl is mixed, it is evenly added to the hopper of the extruder in proportion, and the added material is heated by the screw rotation and the heating device. The mixed material enters the molding device through the rapid pressure release nozzle, and finally passes through the shaping device to obtain degraded foamed plastic products.

Embodiment six

Put 9,000g of cornstarch into a stirred reactor containing 20,000g of deionized water, stir evenly, add 1,000g of methyl acrylate, then add the catalyst cerium ammonium nitrate into the stirred reactor, and continue stirring until the reaction takes 2-3 hours. The reaction product is taken out from the stirring reaction kettle and put into a centrifuge to remove water to obtain the modified starch, and the modified starch is put into a drier for drying, and the dried water content reaches 20wt%. The modified starch with this water content is then pelletized by a single screw extruder. The extruder speed is 20r/min, the aspect ratio is 40, the heating setting of the extruder is turned off, and the working temperature of the extruder is normal temperature.

Put the obtained granules into a dryer, set the drying temperature to 60° C., and dry for 8 hours to obtain Granule 1.

Put the polybutylene succinate into a dryer at a drying temperature of 80°C for 12 hours to obtain Granule 2.

Get the grain one of 60 weight parts and the grain two of 40 weight parts and mix and put into foaming machine (what this embodiment selects is pearl cotton foaming machine, and wherein extruder screw length-to-diameter ratio is 55, and screw speed is 5- 50r/min, the heating temperature is set to 90°C, 110°C, 130°C, 130°C, 120°C, the foaming agent is butane) hopper, at the same time, take 1 weight part of maleic anhydride and 0.1 weight part of Benzoyl oxide is mixed and added to the extruder evenly in proportion. The above-mentioned materials are heated with the screw rotation and the heating device in the extruder. After mixing, melting, homogenization, butane gas injection, mixing and homogenization, extrusion, Cooling molding, sizing and cutting, finished products and other processes to obtain biodegradable foamed plastic products.

Embodiment seven

Repeat above-mentioned embodiment, and by polyterephthalic acid-adipic acid-butylene glycol, polysuccinic acid-adipate-butylene glycol, polyterephthalic acid-succinic acid-butylene glycol or its combination To replace polybutylene succinate, modified starch and polyterephthalic acid-adipic acid-butylene glycol, polysuccinic acid-butylene glycol, polysuccinic acid-hexanediol can be obtained by the same method Acid-butanediol, polyterephthalic acid-succinic acid-butanediol composite biodegradable foamed plastics.

According to the method for producing biodegradable foamed plastics with modified starch involved in the present invention, foam materials such as foam boards, sheets and foam filling particles can be produced.

Claims (10)

1. a method for producing foamed plastics with modified starch, is characterized in that, has following steps to form: A. starch and methyl acrylate are carried out graft copolymerization reaction, make modified starch, and methyl acrylate content is not more than 30wt%; B. adjust the water content of the modified starch so that the water content is 15-30wt%; C. the modified starch obtained in step B is granulated; D. drying the granules obtained in step C until the water content does not exceed 3wt%, to obtain Granule 1; E. select fully biodegradable resin pellets and dry them to obtain pellets 2; F. Mix granule 1 and granule 2 in proportion and add them to the extruder for physical foaming to obtain biodegradable foamed plastics. 2. A method for producing biodegradable foamed plastics by grafting modified starch with methyl acrylate according to claim 1, wherein in said step C, the die temperature of the granulator does not exceed 60°C. 3. a kind of method for producing biodegradable foamed plastics with methyl acrylate graft modified starch according to claim 1, wherein in said step C, extruder is provided with vent, and extruder The temperature of the heating zone shall not exceed 120°C. 4. A method for producing biodegradable foamed plastics by grafting modified starch with methyl acrylate according to claim 1, wherein in step D, the drying temperature is not more than 60°C. 5. A method for producing biodegradable foamed plastics with methyl acrylate grafted modified starch according to claim 1, wherein in the step E, the fully biodegradable resin is polyterephthalene One or Several combinations. 6. A method for producing biodegradable foamed plastics by grafting modified starch with methyl acrylate according to claim 1, wherein in the step F, the weight percentage of grain two is 10--50wt% . 7. A kind of method of producing biodegradable foamed plastics with butyl acrylate graft modified starch according to claim 1, wherein in said step F, after grain one, grain two are added extruder Simultaneously, maleic anhydride and benzoyl peroxide are also added in proportion to the extruder. 8. a kind of method of producing biodegradable foamed plastics with methyl acrylate graft modified starch according to claim 7, wherein the percentage by weight of maleic anhydride is 1-3%, and benzoyl peroxide The percentage by weight is 0.1-0.5%. 9. A method for producing biodegradable foamed plastics with methyl acrylate graft modified starch according to claim 1, wherein in the step F, the physical blowing agent is butane or n-pentane. 10. A method for producing biodegradable foamed plastics by grafting modified starch with methyl acrylate according to claim 1, wherein in the step F, the physical blowing agent is nitrogen or carbon dioxide.