CN1556147A

CN1556147A - Controllable biodegradable plastic mother materal

Info

Publication number: CN1556147A
Application number: CNA2004100210097A
Authority: CN
Inventors: 刘永丰
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-06
Filing date: 2004-01-06
Publication date: 2004-12-22
Anticipated expiration: 2024-01-06
Also published as: CN1256389C

Abstract

A controllable and biodegradable mother plastics is prepared from biodegrading agent (low-molecular hydrocarbon or epoxy soybean oil), thermal oxidizing-degrading promoter (benzene copolymer elastomer), catalyst and polyethylene. It can be biodegraded into H2O and CO2 within 15-38 days.

Description

Controlled-biodegradable plastic base material

The present invention relates to a kind of degradable plastics mother material, exactly is a kind of controllable biodegradable plastic matrix of non-starch.

I adopt the method for easy degradation material of natural biological and plastic blend, have studied the starch-based degradable plastics masterbatch, am to make with W-Gum and polyethylene blend.Starch content is 65% in this masterbatch, and masterbatch has been made the sample testing performance, and the result is tensile strength 7.6Mpa, elongation at break 27%, melt body index 2.4g/10min; This masterbatch is added in the polyethylene, and starch content is transferred to 31%, does not add expanding material in the prescription, and test material intensity, result is tensile strength 11.9Mpa, elongation at break 458%, melt body index 0.78g/10min explanation masterbatch is successful.But, find that starch biodegradation plastics disadvantage is a lot, the one, the loaded down with trivial details and cost height of technology.Starch is strong polar polymer, it and nonpolar polyethylene are inconsistent, if do not change on its macromolecular chain hydroxyl (OH), can not with the non-polar polymer blend, so-called treated starch is cooked this hydroxyl (article OH) (as esterification or carboxylation) exactly, but this article is very bad work, promptly use expensive auxiliary agent with its modification, it and poly consistency are still good inadequately, still need and add the fundamental strength that so-called expanding material just can be guaranteed material, and can play the material narrow range of this expanding material effect, the high thing of its valency is few domesticly not to be produced.The starch water content is up to 10～20%, in heat-processed, to dewater, it is again a kind of high crystalline polymkeric substance, to produce phase transformation in the heat-processed, therefore it is again a kind of thermal unstable polymer, if its is handled bad, under more higher temperature it will dewater, decomposition, flavescence, coking; If be used for blown film, also need starch is carried out thinning processing, thicker 100～200 orders of general commercially available starch granularity, need refine to more than 400 orders with special methods, the 2nd, starch-based degradable plastics, the biological degradation rate of weight loss of measuring, be to be dispersed in the weight that the starch granules in the plastics " is eaten up " by bacterium, be not plastics by biodegradable rate of weight loss, plastics can be by biological degradation or when can be by biological degradation, not reliable test data.The investigator thinks, microorganism digests the amylolysis in the plastics, destroyed the shape of plastics, reduced plastics performance, increased the contact area of plastics and environment, the photosensitizers that adds under light action plays a role, and has destroyed the plastics macromolecular chain, reduce molecular weight, until being digested and assimilated by microorganism.Think from mechanism, this viewpoint has necessity of further exploration, and it is that microorganism is discharged into enzyme in the surrounding medium that microorganism utilizes the mode one of macromolecular material, and the enzyme bacterium plays a role, and is same chemoattractant molecule with material breakdown; The 2nd, microorganism is in order to grow or to survive, microorganism must have the enzyme of a minimum quantity, this kind of enzyme closely contacts with material, enzyme is played a role, enzyme is the catalyzer that biology and surrounding environment are carried out exchange of substance, many microorganisms can be synthesized to aim at and decomposed the employed enzyme of certain compound, could assimilate then to decompose this compound and could eat this compound of metabolism.Be proved to be, diastatic microorganism is an amylase.Can amylase remove to assimilate the polyethylene that decomposes hydro carbons? it is can not have reliable digital proof.If can not the degradative plastics part, this degradative plastics be used for mulch film, and harm will bigger, because small shreds more is difficult to removing.The 3rd, starch-based degradable plastics, workability is all good inadequately, and majority can only be used for injection moulding, extrusion molding or hot compacting, and minority can be used for blown film, still needs with the forcing machine of being furnished with vented screw.I have declared patent of invention " biologically degradable non-starch plastics " (application number: 02109791.7) at 2002.6.4, through one section practice test, feel still to have the place of further raising, revise former patent and be subjected to a lot of restrictions, therefore, declare following patent of invention again.

Investigate the situation of domestic and international biodegradable plastic, except that the composite structure biodegradable plastic in exploratory development, what have feasibility and practicality substantially all is the addition type biodegradable plastic of starch and plastic blend, gel starch additive as the exploitation of USDA research centre, " Eco-star " starch masterbatch of Canada Stlawrence starch company, " Mater-bi " starch degradation masterbatch of Italy Montedison company, the Degradable Starch Resin of China Beijing Institute of Technology development and China use the biodegradation agent in maximum light one biological biodegradable plastics, all are to use starch.The objective of the invention is for people provide a kind of biologically degradable non-starch plastics masterbatch, this kind plastic matrix does not contain the natural biological degradation material, has complete biodegradable, degradation condition is wide, degradation speed is fast, the characteristics of good degrading effect.Its manufacturing process is simple, and the intensity of material is unaffected substantially, can also improve the light transmission of vinyon after the interpolation, and material technology is good, can carry out various processing on general device of plastic processing, and cost is low, does not increase cost.The present invention embodies like this, and it is made up of following each parts by weight respectively: 8～12 parts of non-natural biodegradable material A30～50 parts, 40～60% parts of thermooxidative degradation accelerant B, catalyzer C1～2 parts, polyethylene.

The performance of each component of the present invention and act on as follows:

(1) non-natural biodegradable material A is meant low molecular weight hydrocarbons material or epoxy soybean oil.The low molecular weight hydrocarbons material is a kind of hydrocarbon polymer, is made up of the saturated composition of paraffinic hydrocarbon and naphthenic hydrocarbon, and its molecular weight is low, at C ₁₆～C ₃₈Molecular weight is greatly about 200～560 in the scope.In physical environment, be heated and oxidation that rayed can be slowly, having in the presence of the oxidation degradation of promoter B, it and polyethylene have consistency preferably, do not need that what processing he is done and just can add in the polyethylene, adding 20% when following, polyethylene intensity is not had to influence substantially.A also is the very cheap common material of a kind of price.Experiment showed, this kind hydrocarbons, because its molecular weight is low, end group is many, having catalyzer and oxygen to exist, is having under sunlight and the heat condition, can form a lot of carbonyls on its small molecules chain This group can absorb water in air part and form hydrophilic radical by the hydrogen bond that forms, at this moment solvable the and water of this kind hydrocarbons has also proved above-mentioned micro-variations.This variation not only can be invaded for the enzyme bacterium and be created conditions, and also is the active site that produces free radical under daylight, becomes and quickens important factor of photodegradation.According to the data introduction, when having paraffinic hydrocarbon to exist, the irradiation of sunlight can make between paraffinic hydrocarbon and the Polyethylene Chain and form key, and this kind key has very strong promoter action to polymer degradation.Quickening photodegradation and reduce the plastic molecules amount, created condition for plastics produce biological degradation again, can think, is exactly under this condition, makes non-natural degradable chemical hydro carbons produce biological degradation.According to the data introduction, paraffinic hydrocarbon is to be subject to microbial attack, and harmful bacterial classification is many.

Epoxy soybean oil often is used as the softening agent of PVC, and it is the product after soybean oil is used the peroxidation formic acid oxidation, we can say that also it is the modified fat acid glyceride, and molecular formula is: Contain epoxy group(ing)

And the carboxylic acid group, epoxy group(ing) also is oxidic polyethylene by person, and it and polyethylene have consistency preferably, therefore, are having in the presence of the B material, and it can directly add in the polyethylene, and according to the data introduction, modified soybean oil is that the thing degradation material easily takes place.Also be to the extremely sensitive softening agent of microorganism.The softening agent that particularly contains the part natural goods in the component, particularly responsive to microorganism

(2) B is a thermooxidizing promotor, and it is a kind of copolymer elastomer (segmented copolymer of SBS styrene butadiene styrene), and its molecular formula is:

It main chain and side chain on two strands is all arranged, in physical environment, easily produce photo-oxidative degradation, thermooxidative degradation and ozone oxidation degraded, oxidising process is thermopositive reaction and has autocatalytic action that this carries out compost treatment and produce biodegradation process having created condition with regard to giving this physical obsolescence thing.

The generation of biodegradation process, be under the certain temperature condition, that is to say that biological degradation needs certain heat, macerate excrement ground vapour rising in spring peasant a large amount of stalks and rubbish are carried out compost treatment, cause thermal source with imbedding one in the middle of the manure pit, a large amount of after a period of time stalks and rubbish just become powdered fertilizer, and Here it is in physical environment with thermooxidative degradation guide's biological degradation example.Do not have temperature condition, just can not produce degraded.

Because B is a kind of thermoplastic elastomer, can also play toughened and reinforced effect in plastic substrate, remedy because low molecular weight substance adds the intensity reduction that produces.

(3) catalyzer C is a kind of transition metal ionic organic substance that contains that photodegradation process and thermal oxidation process is had catalysis and booster action.The accelerated degradation process reduces the molecular weight of plastics effectively, is to make plastics produce biodegradable prerequisite.According to the data introduction, many enzymes also need its activity of metal ion species competence exertion, and therefore, selecting catalyzer C for use also is the needs of biodegradation process.

After the present invention realizes, compared with prior art have following advantage:

First, it is different with the biological damage plastics, has complete biodegradable, the biodegradation agent that this kind biodegradable plastic base material is contained, it is a kind of low molecular weight hydrocarbons material, it is identical with the polyethylene chemical structure, belong to the congeneric elements structure, just molecular weight varies in size, and can introduce the enzyme bacterium that this hydro carbons is decomposed in assimilation, to the polyethylene molecule after the photodegradation, also same voltinism should be arranged: this kind hydrocarbons is because molecular weight is low, and its end group is just many, is having in the presence of the catalyzer, it is easily oxidized, can form on the small molecules key and contain carbonyl Hydrophilic group, this kind hydrocarbons is had and can moltenly hydrolysis reaction can take place, can produce thermooxidative degradation reaction etc. after natural biodegradable material has identical hydrophilic radical and extinction group, oxygen uptake with water, the condition that possesses existence of enzyme bacterium and breeding, this not only can invade for the enzyme bacterium and create conditions, it also is the active site that produces free radical, become and quicken a photodegradative important factor, quicken photodegradation and reduce the plastic molecules amount, created condition for biological degradation again, the two complements each other, and finally reaches to make plastics finish biodegradable purpose.Test has confirmed the micro-variations of above-mentioned generation fully.Such just as the artificial culture edible mushrooms, also be to turn out a kind of enzyme bacterium, this kind of enzyme bacterium can assimilate the decomposition hydrocarbons.From the angle of the dialectics of nature, microorganism has the metabolic mechanism of degraded nature organic compound (as Mierocrystalline cellulose, starch, pectin), thereby reaches the balance of organic carbon on the earth.Synthetic compound is to the very strong resistance of degraded performance of microorganism, this be because these compounds to enter natural time ratio shorter, existing microorganism does not also have enough time to form the enzyme bacterium of these compounds of can degrading, but such just as all animals, expansion is also all constantly being opened in their food field, hydrocarbons is original just can be as the nutrition source of microorganism, just the characteristic of molecular structure makes existing enzyme bacterium can not corrode it, and the enzyme bacterium is also being evolved, and function is also improving.The condition of second degraded is wide, as long as in physical environment, just can do biodegradation test to the careless place of sample, and with the Biodegradable film of the technology of the present invention manufacturing, but the open-air physical environment biodegradation test of user's do-it-yourself; The 3rd degradation speed is fast, biodegradable plastic film with the technology of the present invention manufacturing, be placed in the physical environment, in the area, temperate zone in 28～38 days, the small shreds that does not have intensity substantially can be degraded to, in 15～25 days, the small shreds that does not have intensity substantially can be degraded in the torrid areas, the 4th good degrading effect, biodegradable plastic film with the technology of the present invention is made was degraded to the small shreds that does not have intensity substantially at 28 days, and small shreds can break up with hand, become grey powdery, reserved elongation at break is zero during detection, at wind-force, under the mutual percussion of soil, all can become powder, just do not have small shreds for mulch film and remain in the soil, plant is safe from harm; For being used for the life packing bag, discarded back 28 days, the torrid zone was degraded to pulverulence in 15 days, and environment has not been polluted, and white pollution has not existed; This kind film detects proof through provincial authoritative department, also to produce biological degradation behind the film powdered state, this is very with practical value to treatment of urban garbage, plastic packing article was pulverulence or is that carbonic acid gas and water go back to nature by microbiological degradation when composting garbage was handled, can effectively reduce the rubbish volume, prolong refuse tip work-ing life, effectively save the urban environmental protection expense.

Below in conjunction with embodiment the present invention is done further proof.

Embodiment one,

Polyethylene 10 A materials 40

B material 49 C catalyzer 1

By the prescription weighing, put into super mixer and mix the back discharging.Cause particle with the granulation unit again, be the non-starch controllable biodegradable of finished product plastic matrix.Masterbatch is transparent or semitransparent single-size.

Embodiment two,

Polyethylene 70 masterbatch 30

By the prescription weighing, be blow molded into the film of thick 15～50 μ m after mixing with general blown film equipment, do the degraded test with this film.

(1) provincial product detects degradation experiment result of department such as following table:

The biological degradation experimental result

Test event	Measured value	Remarks
Test event	Measured value	Remarks	1, film stretching intensity (Mpa) before the degraded	Laterally: 17.7 is vertical: 17.6	Materials processing is good, and film is even
2, elongation at break (%) before the degraded	Laterally: 260 is vertical: 260	Materials processing is good, and film is even	1, film stretching intensity (Mpa) before the degraded	Laterally: 17.7 is vertical: 17.6	Materials processing is good, and film is even
2, elongation at break (%) before the degraded	Laterally: 260 is vertical: 260	Materials processing is good, and film is even	3, degraded back extension at break retention rate (%)	0	The test of physical environment degraded in the open, in 28 days, film is the powder ash state of no intensity
4, degraded back mass change (%)	6.2	Maximum 6.8% in 10 samples	3, degraded back extension at break retention rate (%)	0

The test-results of degrading is above made by provincial monitoring department, and data are reliable.

(2) open-air physical environment degradation experiment result:

Upper membrane is placed on does open-air physical environment degraded test in the physical environment, experiment is in area, Haicheng City, middle part, the northern Liaoning Province of China, experimental period: began degraded in 15 days on May 29th, 2003, be degraded to remaining flour seldom in 28 days.

Degraded extension at break retention rate 0% illustrates that film has been the pulverulence that does not have intensity, because polyethylene is not a hard brittle material, elongation is 0%, shows that the flexible macromole of polyethylene has been degraded to the quite little small molecules of molecular weight.The extension at break retention rate is 0%, is very useful for being used for mulch film, shows it is not have small shreds to stay soil and suffered.Proved the practicality of this kind degradative plastics.

From the test result of embodiment, when containing A material 12%, the biological degradation rate of weight loss reaches 6.2%, and the biological degradation effect is significant, has illustrated that the low molecular weight hydrocarbons material exists, and under certain condition, polyethylene film can be degraded by microorganisms,

From the test result of embodiment and open-air experimental result, many than the good degrading effect of general light one biological degradative plastics on the effect of degraded illustrates that the polyethylene of maintenance blend intensity in blend has produced biological degradation.Because photodegradation is the molecule chain rupture, biological degradation is that molecule is rotten by the assimilation of enzyme bacterium, so degradation effect is significant.It can also be seen that from embodiment prescription is simple, technology is simple, and is simple.

Claims

The controllable biodegradable plastic matrix of the non-starch of the present invention is characterized in that:

1, utilize low molecular weight hydrocarbons material or epoxy soybean oil to do biodegradation agent, this low molecular weight hydrocarbons material is meant paraffinic hydrocarbon and the cyclic saturated hydrocarbon that contains straight chain saturation alkane, branched-chain saturated hydrocarbon, at C ₁₈～C ₃₈In the scope, about 200～560, the relative density d of molecular weight ₄ ¹⁵0.831 the compounding substances of～0.882. is nontoxic, tasteless, colourless.
2, it does not contain natural biodegradable material, and forms with following each weight fraction component: 8～12 parts of non-natural biodegradable material A30～50 parts, 40～60 parts of thermooxidative degradation accelerant B, catalyzer C1～2 parts, polyethylene.